Anesthesia Techniques, Blood Loss/Fluid Replacement, Airway Management & Convalescence in the Treatment of Dentofacial Deformities

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Anesthesia Techniques, Blood Loss/Fluid Replacement, Airway Management & Convalescence in the Treatment of Dentofacial Deformities

Jeffrey C. Posnick, DMD, MD

Use of Deliberate Hypotensive Anesthesia to Limit Blood Loss

Historical Perspective

Deliberate hypotensive anesthesia (DHA) to provide a less bloody field and better operative conditions was first proposed by Harvey Cushing in 1917 for neurosurgical procedures.⁵⁸ Since then, a spectrum of pharmacologic agents (e.g., nitroglycerine, calcium-channel blocking agents, short-acting beta-adrenergic blockers, purine compounds) and techniques have been used in a variety of combinations in an attempt to accomplish the same objectives.*

In 1950, Enderby and colleagues demonstrated the value of DHA to reduce blood loss in a series of 35 patients.78–81 Eighteen of the 35 (51%) were judged to have an excellent reduction in blood loss during deliberate hypotension, and 8 of the 35 (23%) were judged to have a moderate reduction. The authors attributed this inconsistent effectiveness to individual vascular responses to the hypotensive drugs that were used. They surmised that bleeding at the surgical site could be further minimized if the wound itself was kept uppermost (rather than dependent) through the use of operating room table positioning (e.g., reverse Trendelenburg position for head and neck procedures). Through special positioning, arterial vessels in the operative field would have less pressure, veins would drain more easily, and thus bleeding at the surgical site should be less.

One of the earliest studies to quantify reductions in blood loss with DHA was performed by Eckenhoff and Rich, who completed research in patients who were undergoing a variety of operations, including rhinoplasty, portacaval shunt, and craniotomy for aneurysm.72,73 Half of the patients underwent DHA (n = 115), and the other half (n = 116) went without hypotension. For each of the procedures, blood loss decreased by 50% or more with hypotension techniques. This was the first DHA study to measure blood loss with the use of a control group. By doing so, it greatly added to the power of the research confirming the value of DHA.

Evidence supporting the use of DHA to reduce blood loss has most commonly been found in studies of orthopedic procedures. Thompson and colleagues studied hypotensive anesthesia to reduce blood loss during total hip arthroplasty.²⁵⁵ The mean arterial pressure (MAP) of the patients (n = 30) was reduced to 50 mm Hg. The techniques used to do this included sodium nitroprusside (n = 12) and high inspired concentrations of halothane (n = 9); a control group of patients (n = 9) was normotensive. Blood loss was 1200 mL for the normotensive control subjects but only 400 mL for both hypotensive groups. No anesthesia-specific complications were seen. In 1979, Eerola and colleagues completed a controlled study of 55 patients who were undergoing total hip arthroplasty.⁷⁶ They found that the 38 patients who were given pentolinium tartrate and halothane for DHA had less blood loss. That same year, Vazeery and colleagues studied patients who were undergoing total hip replacement (n = 25). The patients were given sodium nitroprusside to lower arterial blood pressure.²⁶² They had significantly less blood loss than the control group (n = 25), which was not undergoing deliberate hypotension. The value of DHA to reduce blood loss has also been confirmed for other procedures, including craniotomy, middle-ear surgery, radical cancer operations, and a variety of head and neck surgeries.

Didier and colleagues suggested that the depression of cardiac output correlated better with a dry field than did arterial blood pressure.⁶⁶ To determine whether a decrease in MAP or cardiac output was the primary cause of the decreased blood loss, Sivarajan and colleagues studied “healthy” (American Society of Anesthesiologist I) subjects (n = 20) who were undergoing bilateral sagittal split ramus osteotomies of the mandible.²³⁹ Cardiac output decreased 37% with the use of trimethaphan, but it decreased only 27% with sodium nitroprusside. Interestingly, blood loss was similar for both groups, although cardiac output was two times greater with nitroprusside. The authors concluded that blood pressure rather than cardiac output was the primary determinant of how much blood was lost.

Techniques to Induce Deliberate Hypotensive Anesthesia

Currently, the general consensus is that most patients will have less blood loss if the MAP is decreased to 50 mm Hg to 65 mm Hg in the surgical field. It is also believed that patient positioning and attention to ventilation will significantly influence venous return and therefore play important roles in minimizing blood loss. Clinical studies have focused on the use of a variety of specific drugs and combinations of drugs to keep the arterial blood pressure at the surgical site at the level believed to significantly decrease blood loss (i.e., 50 mm Hg to 65 mm Hg).

Body positioning (e.g., reverse Trendelenburg position for head and neck procedures), the hemodynamic effects of mechanical ventilation (e.g., maintaining normal or low carbon dioxide [CO₂] levels), and changes in the heart rate and the circulatory volume are factors that can be manipulated with drugs to lower blood pressure in the surgical field to the desired level. The effective use of these physiologic maneuvers helps to decrease the dose of potentially toxic drugs that are needed to produce the preferred level of hypotension.

The ideal agents for inducing hypotension should have the following characteristics: 1) ease of administration; 2) a predictable and dose-dependent effect; 3) rapid onset; 4) rapid recovery from effects; 5) quick elimination without the production of toxic metabolites; and 6) minimal effects on blood flow to the vital organs. Many anesthetic and vasoactive drugs have been used successfully in clinical practice to induce DHA for orthognathic procedures. These agents primarily include volatile anesthetics; direct-acting vasodilating drugs; beta-adrenergic receptor–blocking drugs; and combined alpha- and beta-adrenergic receptor–blocking drugs. Examples of such agents include sodium nitroprusside, nitroglycerin, esmolol, and labetalol.

Clearly, one can decrease MAP by increasing the amount of inhaled anesthetics such as sevoflurane, isoflurane, and desflurane. Certain drugs that permit moment-to-moment controlled blood pressure are the most popular. The differences in pharmacologic properties among these agents suggest that combinations of these drugs may provide a better pharmacologic profile than could be provided by any agent used alone.²³⁴

Effects of Deliberate Hypotensive Anesthesia on Organ Function

DHA decreases arterial blood pressure by decreasing cardiac output, by decreasing systemic vascular resistance, or by decreasing a combination of the two. Cardiac output must remain sufficiently high not only to provide adequate oxygen and energy substrates to vital organ systems but also to remove metabolic waste products before any accumulation can cause tissue damage. The effect of DHA on cardiac output depends on the balance of its effects on preload, afterload, myocardial contractility, and heart rate. Homeostatic mechanisms also come into play. Other important factors include the physical condition of the specific patient, the anesthesiologist’s administration of additional drugs, and the pattern of ventilation used intraoperatively. The constant assessment of the patient’s intravascular fluid volume throughout surgery is also required to ensure optimal vital organ function.

Inadequate oxygen supply to the brain and myocardium as a result of inadequate tissue blood flow or perfusion pressure is the principal hazard of DHA, particularly with regard to the effects on cerebral metabolic homeostasis.* Studies to date have shown that the responsible use of DHA does not produce permanent changes in cerebral hemodynamics. For example, the cognitive performance of elderly patients on psychological tests given several days after total hip arthroplasty that involved DHA did not differ from their performance before surgery. The current clinical rationale for studying a lower limit for MAP (e.g., 50 mm Hg to 55 mm Hg) in normotensive patients is based on the belief that this range represents the lowest MAP at which autoregulation of the cerebral blood flow is still intact. However, for chronically hypertensive patients or for patients who are older, the curve is thought to shift to the right. In other words, a higher MAP is required in these individuals to maintain autoregulation. The partial pressure of carbon dioxide in the blood (paCO₂) is also an important consideration during DHA. This is because cerebral blood flow changes linearly with paCO₂. Whether one drug is better than another for preserving cerebral blood flow is debated.

The preservation of cardiac function is essential, but it is known to be altered by DHA techniques.^† Interestingly, cardiac function is better preserved with isoflurane than with equal hypotensive doses of halothane. Studies have shown that isoflurane is suitable for healthy patients who are undergoing DHA. Clinical studies also show that the cardiovascular effects of general anesthetic doses of propofol are similar to those of isoflurane. During deliberate hypotension, the maintenance of an oxygen supply that is sufficient for the metabolic needs of the myocardium is of primary importance. As a general rule, patients with known or suspected ischemic heart disease should not undergo DHA.

Renal blood flow normally equals 20% to 25% of cardiac output. Renal circulation is greatly influenced by autoregulatory mechanisms.61,110,159 Clinical studies suggests that normovolemic patients typically experience the rapid recovery of urine production after the discontinuation of DHA.²⁵⁵ Thompson and colleagues could find no significant changes in serum creatinine, blood urea nitrogen, or serum or urinary electrolytes for patients (n = 30) who had undergone DHA.²⁵⁵

Monitoring During Induced Deliberate Hypotensive Anesthesia

Beat-to-beat measurement of arterial blood flow is mandatory for patients who are undergoing clinically significant deliberate decreases in blood pressure. The usual practice is to insert an arterial catheter for the continuous monitoring of blood pressure. Perhaps most importantly, the catheter allows for the intermittent sampling of arterial blood for acid–base status (i.e. metabolic acidosis). It also allows for the confirmation of adequacy of oxygenation and ventilation, and for serial hematocrit measurements. Electrocardiographic monitoring is also essential for detecting signs of inadequate myocardial perfusion or oxygen delivery, such as S-T segment or rhythm changes. The correlation between end tidal CO₂ and paCO₂ is considered somewhat unreliable during hypotension. Nevertheless, capnography still provides useful information during DHA. It may also help to avoid hyperventilation and its resultant hypocapnea, which could be harmful; the decrease in paCO₂ could further reduce cerebral blood flow during moderate hypotension. Pulse oximetry and temperature monitoring should also be routinely used, and the measurement of urine output is also essential. Serum electrolyte, blood gas, and hematocrit levels should also be measured at intervals.

Complications Associated with Deliberate Hypotensive Anesthesia

The precise incidence of complications with the use of DHA is difficult to determine.19,75,41,152,179,248,253 Current data regarding non-fatal complications indicate that hypotension of 50 mm Hg to 65 mm Hg is not a risk factor for young healthy patients (American Society of Anesthesiologists [ASA] 1 and 2). Alternatively, for those individuals with underlying organ dysfunction, the use of DHA may put them at increased risk. Thus, all potential candidates should undergo a complete history and physical examination before surgery. The decision to use DHA should not be made without careful preoperative consideration of patient-specific risk factors.

Special Considerations for the Orthognathic Patient

Before beginning an orthognathic procedure, the logistics of patient positioning, the expected length of the surgery, and the confirmation of patient-specific risk factors for DHA should be discussed by the anesthesiologist and the surgeon.²⁶⁴ Better drugs, more accurate monitoring, a greater level of experience with the techniques, and the consistency of the surgical procedures themselves have permitted a higher percentage of patients to benefit from DHA.* Nevertheless, relative contraindications include a history of cerebrovascular or cardiovascular disease, renal dysfunction, liver dysfunction, peripheral vascular disease, and severe anemia. Fortunately, the orthognathic patient rarely suffers from these dysfunctions. Exceptions include older individuals who are undergoing orthognathic surgery for the treatment of obstructive sleep apnea.^228,261 Given current demographics, this is likely to represent an ever-increasing patient population (see Chapter 26).

Use of Hemorrhage Depressors to Limit Blood Loss

Tranexamic Acids

Tranexamic acid is a synthetic amino acid that inhibits fibrinolysis and that has been shown to reduce blood loss and the need for blood transfusion during specific surgical procedures, including total knee arthroplasty, spine surgery, cardiac surgery, and orthognathic surgery.* It has also been used for the treatment of postoperative bleeding in anticoagulated patients after oral surgery (e.g., the extraction of teeth).^32,212 Senghore and Harris showed that a single intravenous preoperative dose of tranexamic acid was effective for preventing excessive postoperative bleeding in healthy adult patients who were undergoing third molar extraction.²³²

Choi and colleagues completed a double-blind, randomized, controlled trial to study the effects of tranexamic acid on blood loss during orthognathic surgery.⁵¹ This trial included 73 consecutive patients who were undergoing bimaxillary orthognathic osteotomies. Each study patient received either a bolus of tranexamic acid (20 mg/kg) or a placebo (normal saline) intravenously just before surgery. All patients underwent DHA in accordance with standard hospital protocol. Intraoperative blood loss, operative time, the transfusion of blood products, and perioperative hemoglobin and hematocrit levels were recorded. The total blood loss and the blood loss during the maxillary (Le Fort I) procedure were reduced significantly in the group that received tranexamic acid as compared with the control group. The difference in blood loss during maxillary surgery was 428 mL versus 643 mL. The difference in total blood loss was 878 cc versus 1257 cc. The authors concluded that the use of a preoperative intravenous bolus of tranexamic acid (20 mg/kg) reduces blood loss as compared with a placebo during bimaxillary orthognathic osteotomies.

Desmopressin

Desmopressin acetate is an analog to the naturally occurring hormone vasopressin.4,114,115,138,147,222,225,245 It enhances the vascular endothelial cell release of a number of compounds, including high multimetric von Willebrand factor, factor 7c, factor 7ag, and tissue-type plasminogen activator. Desmopressin by itself has been suggested to be the factor that is responsible for the increased hemostatic activity seen in patients with liver dysfunction and uremia. Additional observations indicate that desmopressin may improve platelet function.

Both of these hemorrhage depressors—desmopressin and tranexamic acid—have been used in combination with DHA during orthognathic surgery at the University of Göteborg Hospital since 1999. Zellin and colleagues retrospectively evaluated and compared the total perioperative blood loss for a group of patients who were assigned to either DHA or a combination of DHA and the use of both of these hemorrhage depressors (i.e., desmopressin and tranexamic acid).²⁷⁶ Thirty orthognathic patients who were consecutively operated on via a standardized Le Fort I osteotomy were assigned to either the control group (n = 15) or the treatment group (n = 15). Both groups underwent DHA. The treatment group received additional hemorrhagic depressors (i.e., both tranexamic acid and desmopressin). The mean blood loss was 740 cc in the control group and 400 cc in the treatment group. This was a statistically significant reduction in blood loss in the treatment group (1 g tranexamic acid intravenously and 0.3 µg per kilogram of body weight of desmopressin subcutaneously).

Deliberate Hypotensive Anesthesia Used in Orthognathic Surgery: Review of the Literature

Schaberg and colleagues were the first to evaluate blood loss and the human physiologic response with the use of DHA in the form of sodium nitroprusside during orthognathic surgery.²²⁷ They studied a consecutive series of ASA I patients undergoing Le Fort I maxillary osteotomies. Each was placed in reverse Trendelenburg position (10 degrees), and sodium nitroprusside was used to induce hypotension to not less than 80 mm Hg systolic pressure or 60 mm Hg MAP. The mean estimated blood loss was 256 ± 35 mL. No control group was used for comparison.

Washburn described a retrospective series of 58 individuals who underwent maxillofacial procedures (n = 53 orthognathic patients) in which morphine was used to supplement halothane to induce hypotension.²⁶⁷ The goals were to limit blood loss and to improve the surgical field. There was one death (possibly from halothane-induced liver failure), and only one patient required blood replacement.

Golia and colleagues studied nine patients who underwent either maxillary or combined maxillary and mandibular osteotomies; the DHA techniques that were used included halothane, nitrous oxide, and supplemental doses of muscle relaxants and narcotics.¹⁰⁶ Nitroglycerin was added for the purpose of lowering the MAP during periods with a high potential for increased blood loss (e.g., Le Fort I down-fracture). Estimated blood loss averaged 439 mL and the hemoglobin/hematocrit level fell from 13.8 hemoglobin/41 hematocrit to 12 hemoglobin/36 hematocrit (4.9%). The authors concluded that nitroglycerin was a safe and efficacious agent to help control MAP and blood loss in the surgical field during maxillary and mandibular osteotomies. No control group was used.

McNulty and colleagues completed a study of 12 patients who underwent orthognathic procedures (i.e., Le Fort I osteotomy or sagittal split ramus osteotomy of the mandible) under DHA.¹⁶⁹ The anesthesia agents that were used included fentanyl, isoflurane, and bolus doses (i.e., 10 mg to 20 mg) of labetalol to control the blood pressure in an attempt to improve the surgical field and limit blood loss. The authors reported clinical satisfaction with the surgical field and no complications. No control group was used.

Blau and colleagues compared esmolol in 15 patients with sodium nitroprusside in 15 other patients as the primary drugs for DHA to limit blood loss during Le Fort I osteotomy.³¹ All study patients were physically rated as ASA I or II. The mean MAP averaged 58 mm Hg to 60 mm Hg, with a target range set at 55 mm Hg to 65 mm Hg. The mean heart rate was maintained at approximately 70 beats/min with esmolol and 100 beats/min with nitroprusside. The surgeons generally rated bleeding as mild to moderate and the surgical field as “drier” with esmolol. The total measured blood loss was less with esmolol (i.e., 436 mL with esmolol versus 895 mL with nitroprusside). The authors found the advantages of esmolol as compared with nitroprusside to include greater control of the blood pressure, the reduction of blood loss, and a drier surgical field.

Precious and colleagues studied 50 orthognathic surgery patients in a prospective, randomized, blocked, stratified, and single-blind fashion.²⁰⁶ All patients underwent either sagittal split ramus osteotomies of the mandible, Le Fort I osteotomy, or genioplasty. One group of patients (n = 25) received DHA, whereas the other group (n = 25) received anesthesia with no specific attempt to reduce blood pressure during the operation. The surgeon, who was unaware of which group the patient had been assigned to, rated the surgical field every 15 minutes. At the completion of surgery, three different methods were used to estimate or calculate blood loss. The duration of the procedure was recorded from the time of the first incision to the time of the last stitch placement. The estimated blood loss was significantly less when DHA was used. The surgical field was also rated better, but there was no significant difference in the duration of the procedure with or without the use of DHA. The authors concluded that DHA results in both reduced blood loss and improved visibility in the surgical field.

Enlund and colleagues studied 36 patients who were undergoing orthognathic surgery.⁸⁴ Each patient was randomly assigned to be either hypotensive (n = 18) or normotensive (n = 18) during surgery. Hypotension was achieved with the use of isoflurane to a MAP of 50 mm Hg to 64 mm Hg. The hypotensive group had significantly less blood loss per minute. Only two of the patients in each group underwent bimaxillary osteotomies. A majority of the patients in each group underwent only mandibular ramus osteotomies. None of the patients in either group required blood replacement.

Dolman and colleagues completed a prospective, randomized, blinded-to-the-surgeon clinical trial of DHA in a consecutive series of orthognathic patients.⁶⁹ The purpose of the study was to compare the quality of the surgical field, the blood loss, and the operative time with either hypotensive or normotensive anesthesia during Le Fort I osteotomy. The study patients (n = 23) were randomized into normotensive or hypotensive anesthesia treatment groups. No local anesthesia with a vasoconstrictor was used by the surgeon. In the experimental group, hypotensive anesthesia was maintained with propofol (3 mg/kg/hr), sufentanyl (0.5 mg/kg/hr), and isoflurane (0.5% in 100% oxygen). The quality of the surgical field in both groups was assessed intraoperatively by direct observation and again postoperatively with video imaging. The surgical time was measured on the videotape, and blood loss was measured by volumetric and gravimetric techniques. There was a statistically significant correlation between the surgeon’s perception of the quality of the surgical field and the blood pressure. There was a statistically significant reduction in blood loss when using hypotensive anesthesia. However, there was no significant reduction in operative time when using hypotensive anesthesia. The authors concluded that hypotensive anesthesia is a valuable technique for reducing blood loss and improving the quality of the surgical field during Le Fort I osteotomy.

Praveen and colleagues completed a prospective randomized clinical study to assess DHA and blood loss during orthognathic surgery.²⁰⁴ A total of 53 patients who were undergoing orthognathic surgery were included in the study. The patient ages ranged from 15 to 33 years. They were randomly allocated to have either normotensive anesthesia or to be given DHA. Median blood loss with DHA was 200 mL; under normotensive anesthesia, it was 350 mL. The authors concluded that there was a pronounced reduction in blood loss during orthognathic operations with the patient under DHA as compared with normotensive anesthesia.

Manola and colleagues completed a prospective randomized comparison of three types of pharmacologic agents to induce hypotension during functional endoscopic sinus surgery.¹⁶⁵ The patients were divided into three equal groups in accordance with the agents used: 1) sufentanyl/sevoflurane; 2) remifentanil/propofol; and 3) fentanyl/isoflurane. Evaluation included surgical field rating and measured blood loss. The authors found that the quantity of blood loss and the visibility of the surgical field were improved with the use of either remifentanil and sufentanyl as compared with fentanyl.

Choi and colleagues completed a comparative study to report about the use of three different pharmacologic drugs to induce DHA in patients who were undergoing orthognathic surgery (i.e., Le Fort I and sagittal split ramus osteotomies of the mandible).⁴⁹ The 50 adult patients were randomly allocated to receive either nitroglycerin (n = 25) or remifentanil (n = 25). The MAP and the heart rate were measured at intervals. The heart rates and blood pressures were significantly better controlled with the use of remifentanil as compared with nitroglycerin. Interestingly, there were no significant differences in the surgical field ratings or the measured blood loss between the two groups.

Farah and colleagues completed a comparative study to report on the use of two different pharmacologic protocols to induce DHA in patients submitted to orthognathic surgery.⁹⁰ Twenty ASA 1 patients between the ages of 17 and 44 years were randomly assigned into two groups: group 1 (clonidine and remifentanil) and group 2 (dexmedetomidine and isoflurane). Other drugs that were used as part of the anesthesia regimen were common to both groups. Specific patient parameters were assessed, including arterial blood pressure; heart rate; temperature during the intraoperative and postoperative periods; incidence of nausea and vomiting; postoperative pain; awakening time; extubation time; and postanesthesia recovery time. The results of the study showed that there were no significant differences between the two groups with respect to physiologic responses or surgical time. Both study protocols proved to be effective and safe. Each was suggested as a satisfactory option to achieve DHA during orthognathic procedures when there is an expectation of significant blood loss.

To review, the literature confirms that DHA is effective for decreasing blood loss and providing better visibility in the surgical field during orthognathic procedures. There are many available drugs and techniques that have been used successfully to lower arterial blood pressure to accomplish these goals. The mechanisms of action of available drugs differ and produce complex changes in reflexes and subsequently the blood flow to various organs. For the healthy young patient, complications are rare. The anesthesiologist and the surgeon must assess each patient carefully and consider the potential risks and complications as well as the benefits before using DHA techniques during orthognathic surgery.

The Need for Blood Replacement in Orthognathic Surgery

Background

For individuals who are undergoing complex orthognathic surgery (i.e., Le Fort I and sagittal split ramus osteotomies of the mandible)—often in combination with other simultaneous procedures (e.g., genioplasty, liposuction, septoplasty, inferior turbinate reduction, removal of wisdom teeth)—a preoperative doctor–patient discussion of the need for intraoperative blood replacement is not just an academic issue.92,103,107,149,163,201 Published studies indicate that individuals who are undergoing bimaxillary surgery require blood replacement in the range of 2.5% to 75%.^{15,64,138,142,148,156,200,218,223,226,235,259,274} Rummasak and colleagues retrospectively studied patients who underwent bimaxillary osteotomies (n = 208) during a 4-year timeframe from 2005 to 2009 at a single institution. The authors reviewed possible factors for intraoperative blood loss and looked for statistical significance. They documented that, with consistent anesthesia techniques, the two factors of greatest importance for blood loss were 1) the experience of the surgeon and 2) the overall operative time.²²³

Madsen and colleagues conducted a prospective study to evaluate the predictive value of the viscoelastic properties of whole blood samples collected preoperatively in relation to intraoperative blood loss in patients who were undergoing orthognathic surgery (n = 41). They concluded that, with other variables controlled for, the etiology of intraoperative bleeding can be predicted by means of preoperative thromboelastography. This is a global method that addresses the complex interplay among coagulation factors, blood platelets, and components of the fibrinolytic system. Blood platelet count, activated partial thromboplastin time, prothrombin time, plasma fibrinogen concentration, and D-dimer concentration were determined by routine methods. The authors conclude that thromboelastography results in individual patients can be used for the evaluation of bleeding risk. Further studies will be required to confirm the validity of their findings.¹⁶²

Methods to limit the need for blood replacement continue to evolve and include refinements in DHA techniques as well as in surgical management (i.e., patient selection, collaborative clinical efforts, and the efficiency of the operation and the postoperative care).¹⁰² Despite stringent donor screening criteria and the rigorous testing of every unit of blood, there remains a risk for the transmission of several pathogens.^{70,93,104,108,134,177} For viruses such as the human immunodeficiency virus (1 in 2,135,000), hepatitis B virus (1 in 205,000), and hepatitis C virus (1 in 2,000,000), this is due mainly to “window-period” donations.^34,247 The risks of newly emerging pathogens that can affect blood safety (e.g., Creutzfeldt-Jakob disease) remain unclear. There are other pathogens (e.g., cytomegalovirus, parvovirus B19) that are common in the general donor population and that may pose a risk in the immunosuppressed patient.²¹³ In addition, allogenic transfusion has been shown quantitatively to be an important contributor to postoperative infection.^94,260

The options of autogenous and donor-directed blood banking and their popularity for elective surgery are attributed to their perceived safety, to refinements in blood bank administration, and to public concern about the hazards of allogenic blood replacement.16,86,91,105,118,167,184,210,240 In at least one state (California) and one nation (Germany), the preoperative discussion of blood replacement options is mandated by law and must be documented in the medical record. Other alternatives to allogenic transfusion include acute normovolemic hemodilution, intraoperative blood salvage, and perioperative therapy with recombinant human erythropoietin (Procrit).^{35,101,136,170,173,180,230,231}

The absolute need for and actual use of blood transfusion in the practice of orthognathic surgery remains dependent on considerations that relate to total whole body oxygen delivery and its ability to meet the body’s metabolic needs.56,121,175,189 Many individual hospitals have instituted strict criteria for the transfusion of blood products.²¹⁵ Although mandated criteria may decrease the use of blood transfusions, it remains unclear if complications or delays in recovery have occurred as a result.²⁵⁰

Review of Study

Posnick and colleagues completed a retrospective study to review blood replacement practices in a consecutive series of a single surgeon’s experience with patients who all underwent, at a minimum, simultaneous Le Fort I maxillary osteotomy, bilateral sagittal split ramus osteotomies of the mandible, septoplasty, and inferior turbinate reduction procedures.²⁰² Many patients also underwent additional adjunctive procedures.

A chart review of a consecutive series of the surgeon’s patients (n = 34) who underwent elective bimaxillary orthognathic surgery (Le Fort I osteotomy and sagittal split osteotomies of the mandible) in combination with intranasal (septoplasty and inferior turbinate reduction) and often other simultaneous procedures during a 5-month time frame at a single institution was carried out (see Table 11-1). The chart review occurred at least 3 months after surgery for all patients.

TABLE 11-1

Blood Replacement for Complex Orthognathic Surgery

Asym, asymmetric; auto, autologous blood donation; def, deficiency; exc, excision; F, female; HFM, hemifacial microsomia; homo, homologous blood donation; ICBG, iliac crest bone graft; lipo, liposuction; M, male; mand, mandibular; max, maxillary; OR, Operating Room; RR, Recovery Room; seg(s), segment(s).

From Posnick JC, Rabinovich A, Richardson DT: Blood replacement for complex orthognathic surgery, J Oral Maxillofac Surg 68:54–59, 2010.

Each patient was also evaluated for complications specific to the procedures that were carried out. Potential complications specific to the orthognathic procedures included infection that required the extended use of antibiotics or drainage procedures; dental injury; fibrous union; aseptic necrosis; bleeding that required secondary treatment; and oroantral, oronasal, and orocutaneous fistulas. Potential complications specific to the intranasal procedures included postoperative nasal bleeding that required packing or cauterization; the need for postoperative blood transfusion specific to nasal bleeding; the presence of septal perforation; and postoperative nasal obstruction that required additional procedures within 3 months after orthognathic surgery. Potential perioperative airway compromise was also reviewed, including the need for delayed extubation, reintubation, or tracheotomy. Potential complications specific to transfusions, including infections and autoimmune reactions, were also sought. The patient records that were reviewed included the office chart; the hospital records; and the data stored at the Red Cross (hospital) blood bank. Specific study data collected for each patient (n = 34) can be found in Table 11-1.

The study group included 15 male patients and 19 female patients. The mean age was 22 years and ranged from 13 to 65 years; the median age was 22 years. Thirteen of the 34 patients were less than 18 years old. All patients were treated with a combined orthodontic and surgical (orthognathic and intranasal) approach. The most frequent pattern of jaw deformity that was identified for the study group was asymmetric mandibular excess in 9 out of 34 patients (26%); this was followed by a cleft-craniofacial syndrome being found in 7 out of 34 patients (21%) and a long face growth pattern in 7 out of 34 patients (21%). Additional simultaneous facial procedures that were completed varied. Forty-four percent of the patients (15 out of 34) underwent the simultaneous removal of wisdom teeth. Twenty-one percent of the patients (7 out of 34) also underwent suction-assisted lipectomy of the neck. Eighty-eight percent of the patients (30 out of 34) underwent an osseous genioplasty. Eighteen percent of the patients (6 out of 34) underwent iliac (hip) bone grafting. Fifty-nine percent of the patients (20 out of 34) underwent maxillary (Le Fort I) segmentation. Six percent of the patient (2 out of 34) underwent otoplasty. For all patients, the intranasal procedures included both septoplasty (submucosal resection) and inferior turbinate reduction.

All patients were either extubated in the operating room or within the first hour after surgery while in the recovery room. No patients required overnight intubation, reintubation, or tracheotomy. With respect to complications, no patients required nasal packing or postdischarge blood transfusion. No patient required a return to the operating room for the control of bleeding or airway management.

Twenty-six of the 34 study patients (76%) elected to auto-donate (bank) blood in advance of their surgeries. Two of the 34 study patients auto-donated two units of blood, whereas 24 of the 34 auto-donated just one unit. Only one of the 26 patients that auto-donated received back her banked blood (1 out of 34 or 3% of study patients); she received just one unit of autogenous blood. One of the 34 study patients received a cross-matched anonymously donated (i.e. allogenic) unit (1 out of 34 or 3%). This patient did not elect to auto-donate blood in advance of surgery, and she received just the one unit of blood. Actual autogenous blood use within the group that banked blood was assessed to determine the proportion of discarded stored units. On the basis of the total units of blood that were pre-donated, 28 out of 29 (97%) of the stored units were not used and therefore discarded.

The records of each study patient (n = 34) were specifically reviewed for possible complications associated with the harvesting of autogenous blood and receiving a blood transfusion. Neither of the two patients who received packed red blood cells (one autogenous and the other homologous) experienced intraoperative or postoperative cardiovascular or respiratory compromise. There was no evidence of an adverse event such as an allergic reaction, a transfusion-related infection, hemolysis related to incompatible blood type, or an alteration of the immune system in either patient. According to a review of the blood bank records and discussions with the patients and their families, no complications were known to have occurred as a result of the blood-harvesting process.

Controversies in Blood Replacement for Orthognathic Surgery

Autogenous blood transfusion is the collection and then transfusion of a patient’s own blood. Allogenic blood is collected from someone other than the patient. During recent years, insights into the use of autogenous blood led to a complete revision of the National Heart, Lung and Blood Institute’s recommendations regarding the use of autogenous blood. Despite the reduction of the risk of transmitting viruses such as human immunodeficiency virus, hepatitis B virus, or hepatitis C virus, the transfusion of autogenous blood remains safer than that of allogenic blood, and it is considered appropriate for properly selected patients. However, there is still a risk of adverse reactions, bacterial contamination, and errors in the identification of the units. Directed donations (i.e., blood donations from a friend or family member) for a designated patient are not as safe as the patient’s own blood and must not be considered equivalent to an autogenous blood transfusion.

If transfusion is likely for a planned surgical procedure, there are several theoretical ways of obtaining autogenous blood, including 1) preoperative autogenous blood donation; 2) intraoperative blood salvage; and 3) acute normo-volemic hemodilution. In general, autogenous (intraoperative) blood collection techniques are considered undesirable for orthognathic surgery as a result of the associated saliva contamination. Acute normo-volemic hemodilution is the removal of blood and the simultaneous infusion of cell-free solutions to maintain intravascular volume before surgical blood loss. The removed blood is transfused during or after surgery, as needed, to maintain the desired hemoglobin levels. The use of this technique requires significant clinical expertise because of its associated physiologic consequences, and there is increased risk with DHA during orthognathic surgery.

The current recommendation of the National Heart, Lung and Blood Institute’s conference report is that autogenous blood donations are indicated for patients who are having surgical procedures for which blood is usually cross-matched.¹⁸⁵ The less likely the transfusion for a specific procedure, the more likely that donated blood will not be used. The recommendations are that patients should not be encouraged to donate blood for autogenous use during surgery unless there is a greater than 10% likelihood that they will need it. The historic literature indicates a wide range (i.e., 2.5% to 75%) with regard to the use of transfusion during bimaxillary orthognathic surgery. The review study performed by Posnick and colleagues indicated only a 6% need.²⁰² In current practice, the need for blood replacement during bimaxillary orthognathic surgery may be closer to 2%. The high-risk individual (e.g., an adult with obstructive sleep apnea and other comorbidities) can usually be recognized from the outset, and preparations can be made in advance (i.e., blood typing and cross-matching).

Unfortunately, it is not possible to give a quantitative answer to the question, “When should autogenous or allogenic blood be transfused?” Practical guidelines have been based on hemoglobin levels, but the inadequacy of this parameter is well known. In general, transfusions should be strongly considered when the patient’s hemoglobin level is at 7.0 g per liter (hematocrit = 21) or less. However, in the majority of cases, orthognathic surgery is carried out in young, healthy patients who are free of systemic disease. Thus, there is no absolute hemoglobin level that should automatically trigger a transfusion. A transfusion should be given only on the basis of sound clinical judgment.

Another common question is, “Should the indications for the use of autogenous blood transfusion differ from those for the use of allogenic blood transfusion?” If precise indications for a blood transfusion could be defined, autogenous blood would not be given more frequently than allogenic. Although the benefits of allogenic and autogenous blood transfusions are the same, the risks are not. Therefore, the risk-to-benefit ratio clearly supports the more liberal use of autogenous blood. It has been documented that patients who preoperatively donate blood are more likely to be transfused earlier and more frequently than patients who do not auto-donate. Studies have challenged the use of autologous blood donations for elective surgery, because there is the possibility of blood overcollection, the wasting of autologous units, and the costs of preparation and storage. Cohen developed an interesting mathematical model to analyze the use of preoperative autogenous blood donation.⁵³ The model clarifies how clinicians can customize autogenous blood collection for individual patients to minimize waste (i.e., the need to discard non-transfused blood).

A limited survey of hospitals in the United States determined that the fee generated by the blood bank for each unit of autologous blood that is harvested is estimated to be $255. This includes the storage and delivery of the blood to the operating room or for the disposal of the blood product (i.e., hazardous waste) if it is not used. This fee is typically paid in full by the patient’s medical insurance carrier. If the operative procedure for which the blood is donated is not covered by the patient’s medical insurance carrier, then the patient is expected to pay the fee.

A critical review of the literature and the evaluation of current clinical practice indicates that, with the effective use of DHA techniques, only a small percentage of individuals who are undergoing even complex orthognathic and intranasal surgery should require blood replacement. Close collaboration between the surgical and anesthesia teams and the recovery of patients in a safely monitored environment will continue to improve operating room and postoperative safety and to reduce blood loss and the need for transfusion in the orthognathic patient.

Perioperative Airway Management in the Patient with a Dentofacial Deformity

A basic airway decision for the surgeon and the anesthesiologist to make for the individual who is to undergo orthognathic surgery and who therefore requires general anesthesia is whether to use induced anesthesia and then directly intubate with or without the use of a Glide Scope (Bell Medical Inc., St. Louis, MO); to use awake fiber-optic intubation; or to use a percutaneous technique (e.g., cricothyroidotomy and tracheostomy). The patient with a dentofacial deformity who presents for general anesthesia should be considered to have a difficult airway until it is proven otherwise (Fig. 11-1).^{45,48,123,127,141,146,172,203,207,217}

Figure 11-1 Perioperative risk to the airway and its management should be considered during all phases of orthognathic surgery, including before nasotracheal intubation, during surgery, at the time of extubation, and soon after extubation. Individuals who are scheduled for orthognathic surgery who have been recognized to be at high risk for airway compromise should be discussed in advance with the anesthesia team to arrange for special needs. Three patient examples in which these issues came into play are shown: an adult with Noonan syndrome; a teenage girl with Treacher Collins syndrome; and a teenager with the Klippel–Feil anomaly. Each of these patients also has the potential for cervical spine anomalies with limited neck range of motion. The Risk of spinal cord injury should also be evaluated before orthognathic surgery.

Head and Neck Examination

The head and neck examination of a patient who is scheduled to undergo endotracheal intubation should include his or her mouth-opening ability; the ability to protrude the lower jaw; any limitations of neck extension; the measurement of the thyromental distance; and the Mallampati test.140,164,165 These parameters cover the standard reference points to determine whether or not to expect a difficult airway. These parameters represent components of the basic head and neck airway evaluation recommended in the guidelines of the American Society of Anesthesiologists.⁶

1. Mouth-opening ability. This is measured as the interincisor distance. A value of less than 4 cm has been proposed as an indicator of possible difficult intubation. Fibrous or bony temporomandibular joint ankylosis will absolutely diminish mouth opening. Muscle spasms or pain may also limit mouth opening, but these factors can be overcome with muscle relaxants and analgesics.

2. The inability of the individual to protrude the lower jaw forward. When the mandibular incisors cannot protrude in front of the maxillary incisors, this is considered to be an indicator of a difficult intubation. It is often an indirect test for mandibular retrognathia. In addition, it can be a deceiving indicator of normal jaw morphology in the individual with a normal mandible but with maxillary deficiency.

3. Limited neck extension. An angle of less than 20 degrees as measured between the occlusal surface of the maxillary teeth and the neck when it is in full extension is felt to be suggestive of a difficult direct laryngoscopy. A percentage of dentofacial deformity patients will have cervical spine anomalies that prevent adequate and safe neck extension.

4. The Mallampati test. The visibility of the pharyngeal structures when the mouth is wide open is considered to be of limited use as an individual assessment. However, when this is considered in combination with other physical findings, it is of some value. The dentofacial deformity patient with baseline obstructive sleep apnea is likely to have a Class IV Mallampati classification. The Mallampati classification is determined by having the awake patient in the sitting position open his or her mouth widely and then protrude the tongue completely forward. The clinician then documents which structures can be visualized.

Class I: The soft palate, the fauces, the entire uvula, and the pillars are visualized.

Class II: The soft palate, the fauces, and a portion of the uvula are visualized.

Class III: The soft palate and the base of the uvula are visualized.

Class IV: Only the hard palate is visualized.

5. The thyromental distance. This is often used as an indirect gauge of mandibular morphology. The ratio of a patient’s overall height to his or her thyromental distance may be used as an indirect assessment of mandibular deficiency.

All patients with dentofacial deformities should have documentation by the anesthesiologist of the airway examination, as stated previously. The preoperative evaluation maybe conducted in a clinic setting or immediately before surgery. It is also recommended that the evaluation document the following:

• The status of the teeth (e.g., mobility, missing teeth, removable and fixed appliances, general oral heath);

• The neck circumference (this is an indirect indicator of obstructive sleep apnea)

• The overall body habitus

• Any presenting dentofacial deformity (e.g., maxillo-mandibular deficiency)

• Any anatomic cause of nasal airway obstruction (e.g., septal deviation, posterior choanal atresia, enlarged turbinates)

Prevention of Complications during Tracheal Intubation

According to the American Society of Anesthesiologists, four principles are central to the prevention of complications during tracheal intubation:

1. The maintenance of oxygenation is essential. Preoxygenation is performed before the induction of anesthesia. Mask ventilation is also used in between attempts at tracheal intubation.

2. Trauma to the upper airway must be prevented. The first attempt at tracheal intubation should be performed under optimal conditions (i.e., patient positioning, preoxygenation, and equipment preparation).

3. The anesthesiologist should have a backup plan in place before initiation of the primary technique. He or she must have the skills and equipment needed to execute the backup plan for the patient with a difficult airway. The recent introduction of video-assisted laryngoscopy instruments have lessened the need for more invasive methods to secure the airway, such as the use of a fiber-optic bronchoscope and percutaneous techniques. The backup plan should include the eventuality that, if noninvasive techniques do not restore oxygenation, then cricothyroidotomy (which is generally the percutaneous airway method of choice) is ready to go. In an actual “cannot intubate—cannot ventilate” situation, immediate percutaneous access to the cricothyroid membrane is essential.

4. The anesthesiologist should seek the best help available as soon as difficulty with tracheal intubation is experienced. He or she should be aware of available backup personnel or colleagues who can be quickly called in to assist during an emergency.

NOTE: In the patient with a dentofacial deformity, serious airway morbidity (e.g., cardiopulmonary arrest, or unnecessary tracheostomy)—although infrequent—is a much worse outcome than performing an awake fiber-optic intubation that may not have been necessary.

Video 5

The presurgical airway evaluation by an experienced anesthesiologist provides a reasonable indication of potential intubation difficulty and should always be performed. The anesthesiologist must then make a judgment regarding whether anesthesia induction followed by direct laryngoscopy (as a first effort) followed by mask ventilation with percutaneous rescue (if direct laryngoscopy cannot be accomplished) is likely to be successful. The intrinsic limitations of the pre-anesthesia airway assessment mean that the preparation of an airway strategy for the management of unanticipated difficulties is the ultimate key to safe practice.

When the patient with a dentofacial deformity is felt to be at high risk for challenging airway management, advance planning ensures that necessary equipment and skilled personnel are available. The “difficult airway” is defined as the clinical situation in which a conventionally trained anesthesiologist experiences difficulty with face-mask ventilation of the upper airway, difficulty with tracheal intubation, or both. By definition, the difficult airway represents a combination of patient-specific factors, the specific clinical setting, and the skills of the individual practitioners.

Adequate face-mask ventilation may not be possible as a result of inadequate mask seal, excessive gas leak, or excessive resistance to the ingress or egress of gas. Difficulty with laryngoscopy is said to occur when it is not possible to visualize any portion of the vocal cords. Difficult tracheal intubation is defined as a tracheal intubation that has required multiple attempts in the presence or absence of true tracheal pathology. Failed intubation is defined as the inability to place an endotracheal tube after multiple intubation attempts.

The practical guidelines for the management of the difficult airway have been reported by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway.⁶ The guidelines recommend the following: 1) a detailed evaluation of the airway; 2) a general physical examination; 3) additional patient-specific evaluations, as needed; 4) basic preparation for difficult airway management; 5) a strategy for the intubation of the difficult airway; 6) a strategy for the extubation of the difficult airway; and 7) arranging for follow-up care.

The anesthesiologist should have a preformulated strategy for the intubation of the patient with a dentofacial deformity and a difficult airway. This strategy should include the following:

1. An assessment of the likelihood and anticipated clinical impact of four basic problems that may occur alone or in combination:

• Difficult ventilation

• Difficult intubation

• Difficulty with patient cooperation

• Difficult tracheostomy (cricothyroidotomy)

2. A consideration of the relative clinical merits and feasibility of the three basic airway management choices:

• Awake fiber-optic intubation versus intubation after the induction of general anesthesia

• The use of noninvasive techniques for the initial approach to intubation (e.g., direct conventional laryngoscopy, laryngeal mask airway–assisted airway attainment, video-assisted laryngoscopy) versus the use of invasive techniques (e.g., percutaneous cricothyroidotomy, tracheostomy)

• The preservation of spontaneous ventilation during intubation attempts versus the ablation of spontaneous ventilation during intubation attempts

3. The anesthesiologist must select a primary approach to the difficult airway:

• Awake fiber-optic intubation in the patient who cannot be adequately ventilated and who will be difficult to intubate

• The patient who can be adequately ventilated but who will be difficult to intubate

• The life-threatening situation in which the patient cannot be ventilated or intubated and who will require immediate cricothyroidotomy or tracheostomy

4. The anesthesiologist should formulate in advance an alternative plan in the event that the primary approach is ineffective.

Negative pressure pulmonary edema is an uncommon complication that occurs during the extubation of the trachea in approximately 0.1% of cases.²⁹ It is believed to be a result of laryngospasm. Upper airway obstruction from glottis closure leads to marked inspiratory efforts, which generates negative intrathoracic pressure. This may cause negative-pressure pulmonary edema and, rarely, hemoptysis. Immediately after extubation, the patient will be noted to have marked respiratory distress followed by edema fluid and decreased arterial oxygen saturation, with rising partial pressure of CO₂ levels. A chest radiograph will likely show bilateral pulmonary infiltrates. The most effective form of management is reintubation followed by positive end-expiratory pressure for 12 to 24 hours.

Before the Extubation of the Orthognathic Patient

• Any deliberate hypotensive techniques should be ceased with a return to preoperative hemodynamic stability.

• Any hypothermia should be addressed with rewarming techniques, including temperature-controlled intravenous fluids and warming blankets.

• The patient’s breathing pattern should be regular, with adequate tidal volume (i.e., 6 to 10 mL/kg) and rate of respiration (i.e., 10 to 20 breaths/min).

If the patient was chemically paralyzed, this must be reversed with appropriate agents, (e.g. neostigmine and an anticholinergic agent such as glycopyrrolate). Reversal should be monitored with a twitch monitor, which consists of two electrodes placed at a motor nerve. The ulnar nerve is commonly stimulated to observe the contraction of the adductor pollicis muscle. The return of train-of-four twitches with a ratio of more than 0.9 and with sustained tetany is a method that is used to provide information about the depth of neuromuscular blockade throughout the case and through its reversal at the end. It also allows for the differentiation of depolarizing and nondepolarizing neuromuscular blockade.

• If bispectral index monitoring is used to assess the depth of anesthesia, a return to preoperative levels should be documented.

• Adequate analgesia is maintained with appropriate opioids, but titration with maintenance to a physiologic respiratory rate and tidal volume is required.

• The patient should be sufficiently awake and should have spontaneous eye opening with a conjugate gaze.

• The patient should be able to follow commands (e.g., sustained head lift and hand grip).

• A nasopharyngeal airway (i.e., a nasal trumpet) may be placed to assist with ventilation after extubation.

Checklist of Benchmark Airway Parameters Before Extubation

1. Spontaneously ventilating

2. Paralysis reversed adequately (i.e., sustained tetany without fade for >5 sec)

3. Vital signs stable

4. No longer in Stage II anesthesia

5. Negative inspiratory force of <−20 mm Hg (i.e., you can take off the bag, cover the hole with your hand, and have the patient suck in while you are watching the pressure gauge)

6. “Leak test” for the evaluation of pharyngeal and laryngeal edema

7. Benchmark respiratory parameters:

• Tidal volume >6 cc/kg

• Vital capacity >15 cc/kg

• Blood oxygen saturation >90%

• Respiratory rate <25 breaths/min

• paCO₂ <45 mmHg

In-Hospital Convalescence After Orthognathic Surgery

After extubation, initial management takes place in a recovery room setting. Transfer to a monitored bed either in an intensive care unit or a step-down or telemetry unit is generally preferred. Continuous awareness of the potential for impending respiratory compromise and the need for monitoring to confirm hemodynamic stability is essential early after extubation.²⁶³

Airway Needs

Respiratory issues are of immediate postoperative concern in the orthognathic surgery patient.* The individual must be able to maintain his or her airway as documented by the ability to adequately oxygenate and ventilate. Multiple factors may compromise the airway, including limitations in nasal breathing as a result of the following: 1) the Le Fort I down-fracture with tears in the nasal mucosa; 2) specific intranasal procedures that were carried out (i.e., septoplasty, inferior turbinate reduction); and 3) edema after nasotracheal tube removal. The oral airway will be partially obstructed by the following: 1) ongoing bleeding, secretions, and swelling; 2) the use of guiding elastics; and 3) the presence of an acrylic intra-oral occlusal splint secured to the maxillary dentition. A nasopharyngeal trumpet may be helpful to improve the nasal airway early after extubation. The guiding elastics should be removed, if needed, to improve the oral airway. Active and frequent bedside suctioning is carried out. Supplemental oxygen given via a face tent provides an additional reserve through the nose and mouth; it is titrated to maintain pulse oximetry (i.e., oxygen saturation) of more than 95%, as described later in this chapter.

Monitoring Equipment

Continuous pulse oximetry is essential. This allows for the beat-to-beat monitoring of hemoglobin saturation. It uses a pair of light-emitting diodes to measure the amount of hemoglobin in the oxyhemoglobin formation as a percentage. Normal oxygen saturation ranges from 97% to 100%. It is important to remember that pulse oximetry is not a measure of ventilation but rather of oxygenation. Factors that can result in errors of the “pulse ox” reading include hypoperfusion of the extremity being used for monitoring, high central venous pressures, and carboxyhemoglobin with carbon monoxide poisoning or methemoglobinemia. For these reasons, pulse oximetry does not replace arterial blood gas sampling for a precise measurement of arterial oxygenation. Neither technique is a substitute for a direct physical examination. Recently, technology advances have allowed for the monitoring of both pulse oximetry and capnography in one device. This is done with the use of microstream capnography via bedside nasal prongs along with pulse oximetry. These modalities together improve the ability to assess the adequacy of ventilation and oxygenation during the perioperative period.

Five-lead electrocardiography allows for the monitoring of the cardiac waveform. The most commonly used leads are II and V5 for diagnosing cardiac arrhythmias and cardiac ischemia.

Noninvasive blood pressure monitoring should be used even when an arterial line is also present postoperatively. The continuous invasive arterial blood pressure monitor may be maintained for 12 to 24 hours postoperatively. This will assist with the monitoring of the patient’s arterial blood pressure in a beat-to-beat manner. It may allow for the improved accuracy of diagnosis and better direct the treatment of hypovolemia and hypotension. The arterial line can also be used to draw blood for postoperative laboratory values instead of subjecting the patient to a fresh needlestick.

Whenever there is use of DHA as well as a risk of postoperative bleeding, the maintenance of the intraoperatively placed Foley catheter to monitor urine output soon after surgery is useful. A catheter may be helpful to assess the success of fluid resuscitation and for patient comfort. As a baseline, normal hourly urine output for an adult is 0.5 mL/kg/hr; for a child, it is 1 mL/kg/hr.

Measuring the patient’s temperature both intraoperatively and postoperatively is important. Temperature elevation is a late sign of malignant hyperthermia, which is very rare (i.e., 1 in 50,000 for adults). More commonly, through temperature monitoring, the patient is found to be hypothermic secondary to peripheral vasodilation caused by inhaled anesthetic gases and exposed extremities. Hypothermia can cause the patient to become coagulopathic and to develop arrhythmias and disorders of the metabolism. Core body temperature can be measured via a temperature-sensing Foley catheter. For this modality, the Foley catheter houses a thermistor at the tip that allows for continuous core-temperature monitoring in a safe and minimally invasive manner.

Sequential compression devices placed on the lower extremities are used intraoperatively and maintained during the postoperative period to limit the formation of deep venous thrombosis. These devices increase the velocity of venous blood return to the heart, thereby decreasing venous stasis. In addition, the mechanical compression results in increased fibrinolytic activity within the vascular system. Stockings should be maintained while the patient is immobilized. On postoperative day 1, the patient should be ambulated with assistance, at which point the compression stockings may be discontinued. Multiple studies have documented that early ambulation improves recovery and results in a decreased risk of deep venous thrombosis, the return of bowel function, and earlier hospital discharge.⁶

Wound Care

Intraoral hygiene with Peridex (chlorhexidine 0.12%) and toothbrushing are performed three to five times daily. This is to decrease the bacterial load and the levels of biofilm in the oral cavity. This is especially important, because there are orthodontic brackets, elastics, splints, and exposed sutures in place near and at the incisions. An active oral hygiene routine is initiated the night after surgery by a health care professional. The patient and his or her family are specifically instructed in the techniques by the day after surgery.

In general, there are no external bandages after orthognathic surgery. The patient is encouraged to shower and shampoo his or her hair and to wash his or her face the day after surgery and at least daily thereafter.

Diet

Initial hydration, electrolyte balance, and nutrition are maintained though intravenous fluids. The night of surgery, oral intake is initiated. The orthognathic patient must tolerate liquids for adequate nutrition and hydration before discharge. Inadequate liquid intake may occasionally result in dehydration and the need for readmission after discharge. Caloric requirements in the healthy, non-hospitalized, and non-stressed individual is 15 to 20 Kcal/kg/day. The caloric need will increase substantially in the postsurgical patient, who is, by definition, under stress. A general guideline of caloric need in the patient after orthognathic surgery is 25 Kcal/kg/day. In addition, protein requirements can be doubled from 1 gm/kg of ideal body weight per day to 2 gm/kg of ideal body weight per day.

Surgical trauma to the lips and cheeks initially results in the diminished ability to achieve full lip seal. Without sufficient lip seal, the ease with which one can swallow liquids or drink from a cup is limited (see Chapter 8). A feeding syringe with a soft wide bore tip is initially used. It is placed in the vestibule between the cheek and the posterior teeth to facilitate the direction and depth of entry of liquids. The fluid bolus is injected, and the patient then seals the lips and swallows. The clear liquid diet is rapidly advanced to full liquids to achieve the needed caloric and nutritional intake. The patient transitions from syringe feeding to the use of a “sippy cup” or a squeezable water bottle and then to drinking from a soft glass as soon as he or she is able.

Nausea and Vomiting Management

Postoperative nausea and vomiting are common anesthetic concerns for the patient. If these conditions are not managed, they may in rare cases result in aspiration.236,256 Steps taken to decrease their likelihood include gastric suctioning at the end of the procedure before extubation and the use of prophylactic medications. All orthognathic patients are given prophylactic antiemetic therapy. A medication regimen may include the following: glucocorticoids such as dexamethasone at the onset of surgery; ondansetron (Zofran) or granisetron (Kytril) 15 minutes before the conclusion of surgery; metoclopramide (Reglan); and the judicious intake of liquids immediately after extubation. Multimodal antiemetic therapy in the recovery room should be employed for refractory cases of nausea and vomiting; this may include promethazine, compazine, and repeat doses of ondansetron-like agents. Appropriate postoperative patient monitoring and bedside access to a mouth-suctioning device are essential. As long as the patient can maintain protective airway reflexes, episodes of vomiting (with only liquids on the stomach) should have minimal serious sequelae.

Intravenous Fluid Therapy

The preoperative number of hours of “nothing-by-mouth” status, the individual’s body weight, and the intraoperative fluids given and lost need to be quantified. This process allows for a precise representation of the patient’s fluid balance and ongoing fluid and electrolyte needs. The intravenous fluid needs must account for both sensible and insensible losses. Once maintenance fluids are calculated, a determination of estimated fluid deficit (EFD) should be made. Intraoperative third space loss and blood loss will also be taken into account. Fluid administration needs to be titrated to maintain hydration and desired urine output.

A starting point to estimate maintenance fluid needs after surgery can be given with the use of the following formula:

• 4 mL/kg/hr for the first 10 kg of body weight

• 2 mL/kg/hr for the next 10 kg of body weight

• 1 mL/kg/hr for every 1 kg of body weight above 20 kg

Pain Management

The postoperative orthognathic patient has pain requirements that are similar to those of any other surgical patient. Analgesia is required for the progression of the patient to recovery. Initial postoperative requirements are best maintained with intravenous medication, whether it is administered by the nursing staff or patient controlled. Multiple studies have confirmed that patient-controlled analgesia is safe, effective, and not likely to result in oversedation or respiratory compromise. Intravenous morphine sulfate is routinely used. By the morning after surgery, the patient is transitioned to a liquid form of opioid that taken at 4- to 6-hour intervals as needed for analgesia. It would be unusual for the patient to require or request opioid pain control by the second week after surgery. The transition from intravenous analgesics to an oral form is essential for the patient’s discharge and his or her comfortable transition to home care.

Antibiotics

Multiple studies have confirmed the benefit of prophylactic doses of antibiotics for clean-contaminated (Class II) surgery and specifically for orthognathic surgery to decrease wound infection rates. This is typically initiated as a prophylactic dose of the first-generation cephalosporin cefazolin (Ancef); 15 to 20 mg/kg and up to 1 g is given before surgical incision and then every 6 hours. The postoperative course of intravenous antibiotics continues while the patient is still in the hospital. Antibiotics are then given orally upon discharge for a total of no more than a 5-day course. Opinions vary with regard to the extent of use of antibiotics for orthognathic surgery. Bentley and colleagues performed a randomized controlled trial that compared a 1-day regimen with a 5-day regimen of antibiotics for patients who were undergoing orthognathic surgery.²⁴ A group of 30 patients who were undergoing combined maxillary and mandibular osteotomies was divided equally. Nine out of 15 patients in the 1-day antibiotic group developed postoperative infection, whereas only 1 out of 15 patients in the 5-day antibiotic group did. The authors concluded that a 5-day course of antibiotics is useful to decrease the risk of postoperative infection (see Chapter 16).

Nasal Medications

The use of specific nasal medications after surgery varies by surgeon preference. Many surgeons recommend that, after surgery, several days of an intranasal decongestant be given to open the nasal airway and improve patient comfort. These can include Neo-Synephrine nasal spray, oxymetazoline (Afrin) nasal spray, or a corticosteroid such as Rhinocort. In addition, saline nasal spray improves the humidification of the nasal passages and limits the drying of the nasal mucosa, which may decrease the risk of epistaxis and improve patient comfort. A pure nasal saline spray has the advantage of not having a rebound effect as compared with the pharmacologic agents. This is the requirement that I prefer.

Criteria for Discharge from Hospital

Discharge planning for the orthognathic patient should begin before surgery. There should be ample preoperative communication with the patient and the patient’s family or significant others to prepare for the anticipated postoperative care requirements, including medications, diet, oral and body hygiene needs, and activity level. Basic criteria for discharge from the hospital include the following:

• The ability to ingest sufficient liquids orally (i.e., hydration and nutrition)

• The absence of significant fever

• Stable vital signs, including the maintenance of pulse-oximetry documented oxygenation while sleeping

• The absence of continued nausea and vomiting

• Sufficient ambulation to carry out necessary activities of daily living in conjunction with a designated family member, friend, or caregiver

• Adequate pain control with oral analgesia while in the hospital

• The demonstrated ability to achieve required body and oral hygiene

At-Home Convalescence and Outpatient Care After Orthognathic Surgery

When feasible, our preferred outpatient regimen involves weekly office visits for 5 weeks after orthognathic surgery. Although the frequency and duration of routine postoperative office visits will vary from surgeon to surgeon, there is no substitute for a face-to-face discussion and a hands-on examination with the patient to clarify expected progress, to identify potential problems, and to institute timely treatment during the early phases of healing.

Important aspects to monitor early after orthognathic surgery include the following: 1) diet, hydration, and nutrition; 2) oral and body hygiene; 3) physical activity level; 4) emotional well-being; 5) medication use; 6) swelling and wound healing; 7) occlusion and jaw mobility; and 8) adequacy of the oral and nasal airways. The need for physical therapy related to A) lip seal and control exercises, B) sensory retraining exercises, and C) mouth-opening exercises is also assessed. Each of these parameters is addressed during each postoperative office visit. When weekly visits with the surgeon are not geographically convenient, an appropriate clinician closer to home (i.e., an orthodontist and surgeon) can generally be found. This is best supplemented with a phone call and the viewing of e-mailed facial photos sent to the primary surgeon.

Patient Education Materials

Patient Instructions for Orthognathic Surgery

The purpose of these basic instructions is to help you prepare and then recover from your operation with as little discomfort and inconvenience as possible.

Preoperative Instructions

1. During the 2 to 6 weeks before your planned operation, you will return to my office to have current dental and facial records taken; to undergo further head and neck examination; and to allow for the completion of analytic model planning.

2. During the 2 to 6 weeks before your surgery, make arrangements for a physical examination by your family physician that includes necessary laboratory tests to confirm your health. We will provide you with a form for your general physician to complete.

3. Do not take any aspirin, aspirin-like products, or any other medications that may increase bleeding for at least 3 weeks before surgery. Aspirin and aspirin-like products tend to increase bleeding during surgery and bruising postoperatively.

4. If you take or have taken a bisphosphonate medication (e.g., for osteoporosis or osteopenia therapy), you must let us know, because your risk for bone-healing difficulties may be increased.

5. Be sure that you do not smoke and that there are no nicotine products in your bloodstream for at least 3 weeks before and 2 weeks after surgery. Nicotine in the bloodstream jeopardizes wound healing. Smoke that is chronically ingested by the lungs may result in pulmonary complications that will hinder optimal healing.

6. Starting 2 days before surgery, we request that you shampoo your hair and shower at least once per day. The morning of surgery, you may also shower and shampoo your hair again.

7. Do not eat or drink anything after midnight the night before surgery, not even a sip of water. You may brush your teeth, but do not swallow the water.

Postoperative Instructions

1. In general, you will remain in the hospital for 1 or 2 nights during your initial recovery. When you are up and around, drinking enough fluids, and have recovered some of your strength, you will be able to return home to the care of your family.

2. Instructions for a high-protein blenderized (pureed) diet will be discussed with you. In general, the pureed (blenderized) diet will continue for 5 weeks, after which you will gradually return to the eating of regular foods.

3. Exercising your lips (e.g., squeezing them together for closure) during the first several days after surgery is helpful. By doing so, you will more rapidly regain lip control, reduce facial swelling, and find it easier to swallow fluids and control your saliva.

4. You will begin brushing your teeth with a soft toothbrush the day of the operation. We will prescribe a special antimicrobial mouth rinse to reduce the plaque (bacteria) buildup on your teeth.

5. In general, no facial bandages will be used after surgery. You should take a shower and wash your hair and face the day after surgery. Initially, you should have someone close by when you shower, because you may feel unsteady on your feet.

6. It is advisable to sleep with your head in an elevated position (e.g., on two pillows) for at least the first week after surgery. This helps with the natural drainage of fluids in the facial area, and it also helps to decrease swelling.

7. Nasal congestion (i.e., difficulty breathing through the nose) is to be expected immediately after surgery. The congestion generally takes 5 to 7 days to significantly clear. Until then, frequent steamy showers and the use of saline nasal sprays will be helpful. You should avoid blowing your nose after surgery, because doing so may increase the risk of bleeding. When you sneeze, let the air go through your mouth to limit the pressure in your nose.

8. When you get home, you should take the prescribed pain medication as needed. Tylenol may be substituted when your pain has diminished. Avoid taking aspirin or aspirin-like products for an additional 2 weeks after surgery.

9. Your sleep schedule will be irregular during the initial weeks after surgery. You may substitute Benadryl for the pain medication to assist with sleeping, but only after permission is received from your surgeon.

10. You will be given a prescription for an antibiotic. Take it as directed until the supply is exhausted. If you develop a skin rash, diarrhea, or a vaginal infection, stop the medication and contact your surgeon, because these problems may be related to your prescription.

11. Do not drink any beverages that contain alcohol, take any non-prescribed medications, or drive a motorized vehicle until you have been given permission to do so.

Additional Considerations

1. A cold pack placed over the cheek and neck region on each side of the face is useful during the initial 24 to 36 hours after surgery to limit swelling. Nevertheless, you will be swollen, and your skin will be discolored (i.e., black, blue, green, and yellow) for several weeks after surgery. The swelling and discoloration are never the same on the two sides of the face and neck, and they will be seen halfway down your chest. Remember that each side of the face heals somewhat independently. The initial soft-tissue swelling will not influence the final results. Although the swelling decreases significantly by 5 weeks after surgery, 6 to 12 months is required for all swelling to subside.

2. There will be numbness or decreased sensation in specific regions of your mouth and face. This takes some time to get used to, and it will improve considerably. The location of the diminished sensibility of the skin of the face and the mucous membranes of the mouth will be dependent on the specific procedures that are carried out. I will explain this to you in detail at your first consultation and again during office visits before your operation; this information will also be found on your informed consent document.

3. In general, at 5 weeks after surgery, basic healing is sufficient enough for you to gradually return to physical activities such as jogging, bicycling, and aerobics. At this stage, progression to a more regular (chewing) diet is also encouraged.

Physical Therapy after Orthognathic Surgery

1. Early after orthognathic surgery the loss of full lip control/seal results in drooling and difficulty swallowing a bolus of liquid. The lip-control difficulty results from a combination of factors, including A) surgical trauma to the soft tissues of the lips; B) the expected diminished sensation; C) the change in the position of the jaws and teeth; and D) the presence of an intra-oral occlusal splint, elastics and orthodontic lugs. Instituting active lip closure and control exercises beginning the day after surgery will help you to regain lip-seal control for ease of swallowing and managing your saliva.

2. Within the first few weeks after surgery, instructions will be given to help you to achieve the gradual return of normal mouth opening. If the adequate return of mouth opening, speech articulation, and lip control are slow in coming, then the institution of active range-of-motion mouth exercises and speech therapy will be arranged.

3. Some individuals have more difficulty than others adjusting to the expected loss of sensation after a Le Fort I maxillary osteotomy (involving the infra-orbital nerves) or sagittal split ramus osteotomies of the mandible (involving the inferior alveolar nerves). The institution of sensory retraining exercises may be helpful to desensitize you to the altered sensibility and the expected gradual recovery in specific facial and oral locations.

Jeffrey C. Posnick, DMD, MD

Director, Posnick Center for Facial Plastic Surgery

Physical Therapy after Orthognathic Surgery

• Lip Closure/Control Exercises

• Mouth-Opening Exercises

• Sensory Retraining Exercises

Lip Closure/Control Exercises

Patient Instructions (to begin the day after surgery)

Keep in mind that many patients with jaw deformities (e.g., long face growth pattern) have never been able to easily obtain full lip seal. Beginning the day of surgery, we encourage active lip closure/control exercises. Initially, the exercises are carried out by the patient under the direction of a health care professional. The patient should look at his or her lips with the use of a handheld mirror. Attempting to squeeze the lips together while viewing them in a mirror generally provides for a successful lip seal within 12 to 24 hours. Until lip seal can be achieved, it is difficult to effectively swallow liquids without drooling a portion of the liquid out of the mouth. After a consistent lip seal is achieved, the ability to swallow saliva and to drink sufficient quantities of liquids for the maintenance of hydration and adequate caloric intake is the norm. With diligent effort, the required level of lip control is generally achievable by 24 to 48 hours after surgery.

Mouth-Opening Exercises (Modified University of North Carolina Instructions)

Level I Patient Instructions (2 to 5 weeks after surgery)

Basic Mouth-Opening Exercises

Do these mouth-opening exercises at least three times a day for 2 to 3 minutes each time: once in the morning, once at midday, and again in the evening.

1. First, remove the elastics, and then practice opening your mouth and moving your jaw side to side by just using your jaw muscles.

2. Do not try to open or move beyond what causes only mild discomfort for a short period of time. Do not force the opening if it hurts.

3. Do not do the mouth-opening exercises with your elastics on. Avoid forcefully opening your mouth by straining against the rubber bands that hold your jaws together.

By the end of the third week, you may be able to open your mouth wide enough to get one finger between your front teeth when the elastics are off. By the end of the fifth week, you may be able to get two fingers between your teeth when your elastics are off.

Hold-and-Relax Exercises

If you cannot open your mouth wide enough to get one finger between your front teeth at the end of the third week, start these hold-and-relax exercises.

1. Open your mouth about half of the amount that is comfortable.

2. Fold your hand into a fist, and place your fist under your lower jaw.

3. Using gentle pressure, push up with your fist as if you are trying to close your mouth.

4. Use your jaw muscles to try and open your mouth against the pressure of your fist. Hold this pressure for about 5 seconds, and then remove your fist and close your mouth.

5. Next, spend 30 to 60 seconds moving your jaw side to side and gently stretching and opening your mouth just using your jaw muscles.

6. Repeat the hold-and-relax exercise followed by moving the jaw side to side about five times.

Level II Patient Instructions (5 to 9 weeks after surgery)

Hold-and-Relax Exercise

Do two or three repetitions of the hold-and-relax exercise three times a day: in the morning, at midday, and in the evening. (See the Level I instructions for this exercise.)

Finger-Stretch Exercise

1. Place your middle finger on your lower teeth in the bicuspid region, and place your thumb on your upper teeth in the bicuspid region.

2. Apply pressure with your fingers so that it creates the feeling that you are stretching the jaw muscles. There will be some feeling of tightness or mild discomfort. Hold this for 5 seconds, and then release your fingers and close your mouth.

3. Next, move your jaw side to side and open and close your mouth using your jaw muscles for 30 to 60 seconds.

4. Repeat the finger-stretch exercise but with your fingers on just one side of your mouth at a time. Follow this with the side-to-side exercise.

Do the finger-stretch exercise three times on each side. Each time, try to slightly increase the finger pressure to produce more opening. Producing a feeling of mild discomfort is okay, but do not push enough to create pain.

Sensory Retraining Exercises (Modified University of North Carolina Instructions)

Level I Patient Instructions (2 to 5 weeks after surgery)

Basic Touch Exercises

Do the touch exercises with a brush (i.e., a toothbrush, hairbrush, or makeup brush) at least three times a day for 2 to 3 minutes each time: in the morning, at midday, and in the evening.

1. Start by looking in the mirror, and watch what you are doing with the brush.

2. First, alternate touching and stroking your face with the brush.

3. When you start the exercise, make long strokes that extend from one side of the face to the other.

4. As you do the exercises, vary where you first touch your face before starting the stroke. Do this on different parts of your face (i.e., forehead, cheeks, chin, and upper and lower lip).

5. The brush should be moved at the same rate that you might use your fingertips to touch or examine a piece of cloth.

6. Be sure to move the brush around on both sides of your face. Do not spend all of your time on any one spot.

Additional “Touch” Exercises

Close your eyes, and either touch or stroke your face with the brush. Tell yourself whether you are going to touch or stroke your face with the brush before you do it. If you have someone at home to help you with the exercises, ask him or her to either touch or stroke your face with the brush.

For the first five or so tries, be sure that your partner tells you before the brush touches your face whether it will be a touch or a stroke.

Try keeping your eyes closed, and then let your partner either touch or stroke your face with the brush without telling you what to expect.

If you can easily tell a touch from a stroke, that’s great. Remember to decrease the length of the stroke about a quarter of an inch every other day; this will make the task more difficult.

The length of the stroke should result in it being challenging (but not impossible) for you to tell the difference between a touch and a stroke. Remember also to use both side-to-side strokes and up-and-down strokes. If you have difficulty even with long strokes, do not become frustrated. Most individuals sense little change from day to day. It is important that you be patient and persistent.

You can practice the touch exercises as many times during the day as you wish. Looking in the mirror while you practice is very important. If you do not have a brush with you, simply use a light finger touch.

Level II Patient Instructions (5 to 9 weeks after surgery)

Basic Touch Exercises

Do the touch exercises with the brush at least three times a day for 2 to 3 minutes each time: in the morning, at midday, and in the evening. When you begin, look in the mirror and watch the movement.

1. At first, alternate stroking your face side to side or up and down.

2. As you do the exercises, vary where you make the strokes on your face.

3. When you begin the exercises, start the side-to-side exercise on one side of the face, and stroke across the entire region to the other side of the face. For example, move from the bottom of your ear across your upper lip to the bottom of your other ear.

4. When you stroke up and down, start on your neck, and go all the way up and down your face. For example, move from your neck all the way up the side of your face to the forehead, or start just below your eye and stroke down to your neck.

5. While doing the exercise, tell yourself that whatever sensation you feel is normal and expected.

6. Seeing the orientation of the stroke and the area of the face that you are touching reflected in the mirror and telling yourself that all of the sensations you feel are normal and expected is important.

7. Be sure to move the brush around on both sides of your face. Do not spend all your time on any one spot.

Additional Touch Exercises

Close your eyes. Before you stroke your face with the brush, tell yourself whether you are going to stroke your face side to side or up and down with the brush. If you have someone at home to help you with the exercises, for the first five or so tries, be sure your partner tells you before the brush touches your face whether it will be a side-to-side or up-and-down stroke. Next, try keeping your eyes closed, and let your partner do the exercise again without telling you what to expect.

If you can easily tell an up-and-down stroke from a side-to-side stroke, that’s great! Remember to decrease the length of the stroke by about a quarter of an inch every other day; this will make the task more difficult. The length of the stroke should result in it being challenging (but not impossible) for you to tell the difference between an up-and-down stroke and a side-to-side stroke.

If you have difficulty even with long strokes, do not become frustrated. Most patients sense little change from day to day. It is important that you be patient and persistent.

Jeffrey C. Posnick, DMD, MD

Director, Posnick Center for Facial Plastic Surgery