Patients who are unconscious (Glasgow Coma Score <8; see Chapter 37) or who have a reduced level of consciousness may develop partial or complete upper airway obstruction due to prolapse of the base of the tongue into the oropharynx (Fig. 40-1A). Treatment involves the head-tilt, chin-lift maneuver, in which the neck is extended at the atlantooccipital joint and the mandible is thrust forward (Fig. 40-1B). An oropharyngeal airway may also be inserted (Fig. 40-1C). A correctly sized oropharyngeal airway should extend from the patient’s lips to the ear; a size 3 (green) or 4 (orange) is suitable for most adults. If the patient is partially conscious, an oropharyngeal airway may precipitate coughing, vomiting, and laryngospasm.

Figure 40.1 Basic airway management. A, Mechanism of airway obstruction. B, Technique of head-tilt, chin-lift to maintain a patent airway. C, Oropharyngeal airway in situ; D, Technique of bag-mask ventilation. See text for details.

Bag-Mask Ventilation

In patients who are apneic, bag-mask ventilation should be performed using a self-inflating manual resuscitator with an oxygen reservoir bag (see Fig. 28-1). To ensure that the reservoir bag remains filled, an oxygen flow of 15 l/min is typically required. Ventilation via mask requires a tight fit. The correct position of the operator’s hand is shown in Figure 40-1D. It may be possible to achieve a patent airway and a good mask seal with a single hand; if not, two hands should be used, and an assistant should perform the bag compressions. The bag should be inflated 12 to 16 times per minute, and the chest should be seen to rise and fall, while using the lowest effective pressure to minimize the risk of gas insufflation of the stomach.

ENDOTRACHEAL INTUBATION

Intubation of the trachea may be required to provide invasive ventilation, to facilitate tracheal toilet, or to protect the airway when consciousness is reduced. In the ICU, endotracheal intubation is commonly required urgently for treating respiratory distress or cardiac arrest.

The airway should be assessed to gauge the likelihood of difficulty with laryngoscopy and intubation (Fig. 40-2 and see Table 40-1).² Reports of previous intubations should be reviewed. If difficulty is anticipated, awake fiberoptic intubation should be considered (see subsequent material).

Figure 40.2 Samsoon and Young modification of the Mallampati classification. Class I, the fauces, soft palate, and the entire uvula are visible. Class II, the soft palate, fauces, and part of the uvula are visible. Class III, only the base of the uvula and the soft palate are visible. Class IV, only the hard palate is seen. Class III and IV are associated with increased difficulty of intubation.

(Redrawn from Samsoon GL, Young JR: Difficult tracheal intubation: a retrospective study. Anaesthesia 42:487-490, 1987.)

Table 40-1 Indicators of Difficult Intubation

Sign	Notes
Reduced mouth opening	Patient has an interincisor distance of <4 cm.
Reduced thyromental distance	Measured with the neck extended; less than 6.0 cm is abnormal; 6.0 to 6.5 cm is borderline.
Mallampati score 3 or 4	See Fig. 40-2.
Limited neck movement	Patient is unable to extend the neck at the atlantooccipital junction or flex the neck.
Reduced mandibular subluxation	The mandible is normally able to be protruded so that the lower incisors are in front of the upper incisors.
Large incisor teeth	Difficulty intubating an edentulous patient is very rare.
Large incisor teeth	Large upper incisor teeth are associated with difficulty.

Unlike patients who are to undergo general anesthesia for elective surgical procedures, patients requiring endotracheal intubation in the ICU can rarely fast for 6 hours beforehand. Also, ICU patients commonly experience delayed gastric emptying due to the effects of opioids, pain, anxiety, and shock, and they cannot be assumed to have empty stomachs, even if they have appropriately fasted. Therefore, for most intubations performed in the ICU, a rapid-sequence technique is indicated. If possible, a proton pump inhibitor (e.g., omeprazole 40 mg intravenously) may be given at least 30 minutes beforehand. The nasogastric tube (if present) should be suctioned before proceeding.

Necessary equipment and drugs are listed in Tables 40-2 and 40-3, respectively. An 8.5-mm (internal diameter) endotracheal tube is suitable for most adult males and a 7.5-mm tube is suitable for most adult females.

Table 40-2 Equipment for Endotracheal Intubation

Selection of face masks

Selection of oropharyngeal airways

Self-inflating manual resuscitator with oxygen reservoir

Two laryngoscopes with a variety of curved and straight blades

Selection of endotracheal tubes, one opened with its cuff checked

Oxygen source and tubing

High-pressure suction with Yankauer connector

Intubating bougie

Endotracheal tube stylet

Magill forceps

A syringe for cuff inflation

Tape or ties for securing the endotracheal tube

Head support

Equipment for managing difficult intubation, for example:

Laryngeal mask airway

Fiberoptic bronchoscope

Monitoring

Pulse oximeter

Capnography

Electrocardiogram

Blood pressure

Adequate venous access

Drugs for induction of general anesthesia (see Table 40-3)

Table 40-3 Drugs That Should Be Drawn Up Prior to Rapid-Sequence Endotracheal Intubation

Hypnotic

e.g., etomidate 0.1 to 0.2 mg/kg

e.g., ketamine 1 to 2 mg/kg

e.g., propofol 0.5 to 2 mg/kg

Opioid with rapid onset

e.g., fentanyl 0.5 to 5 μg/kg

Suxamethonium

1.5 mg/kg

Nondepolarizing neuromuscular blocking drug

e.g., pancuronium 0.1 mg/kg

e.g., vecuronium 0.1 mg/kg

Atropine

600 μg/dose

Vasopressor

e.g., phenylephrine 50 to 100 μg/dose

e.g., metaraminol 0.5 to 1 mg/dose

Saline flush

Patients should be monitored by pulse oximeter, ECG, blood pressure cuff, or intraarterial cannula as well as by capnography. A fast-flowing intravenous cannula, preferably into a central vein, should be used for administering drugs.

Three staff members are required for the procedure: (1) an operator who stands at the head of the bed and performs preoxygenation, laryngoscopy, and intubation; (2) an assistant on the operator’s left who performs cricoid pressure; (3) an assistant on the operator’s right who administers drugs, retracts the upper lip, and hands the endotracheal tube to the operator.

Rapid-Sequence Intubation

Rapid-sequence intubation involves the induction of general anesthesia and neuromuscular paralysis, followed promptly by endotracheal intubation. The risk of regurgitating and aspirating gastric contents is minimized by the application of cricoid pressure and avoiding bag-mask ventilation.³ The cricoid cartilage (Fig. 40-3) is the only complete cartilaginous ring. Firm pressure on the cricoid cartilage compresses the underlying esophagus and helps to prevent regurgitation of gastric contents.

Figure 40.3 External anatomy of the larynx and trachea. Note that the isthmus of the thyroid gland may overlie the first through third tracheal rings, the target level for percutaneous tracheotomy.

(Redrawn from Ellis H, Feldman SA, Harrop-Griffiths AW: Anatomy for Anesthetists, ed. 8. Oxford, U.K., Blackwell Publishing, 2004.)

The technique is performed as follows:

1. Preoxygenation. If possible, preoxygenation with 100% oxygen via a manual resuscitator and a tightfitting mask should be performed for at least 5 minutes. This is best performed when the patient is in a sitting or semirecumbent position.

2. Positioning. The patient should be placed in a flat supine position with the head in the “sniffing” position. The cervical spine is flexed by placing two pillows behind the head, and the atlantooccipital joint is extended.

3. Induction of anesthesia and paralysis. Predetermined doses of the opioid, the hypnotic, and suxamethonium should be given as rapid boluses, without waiting for effect.

4. Cricoid pressure. Pressure should be applied as soon as the patient is asleep.

5. Intubation. Once suxamethonium fasciculations have ceased, direct laryngoscopy and tracheal intubation are performed. The tracheal cuff is inflated until the pilot cuff is firm and there is no leak around the tube.

6. Confirmation of successful tracheal intubation. See subsequent material.

7. Release of cricoid pressure. Once the operator is satisfied that the airway is secure, he or she instructs the assistant to release cricoid pressure.

The endotracheal tube is secured with tape or a tie and the patient is connected to the ventilator. A nondepolarizing neuromuscular blocking drug is administered, and a chest radiograph is ordered.

Technique of Direct Laryngoscopy and Intubation

Direct laryngoscopy is usually performed using a curved (MacIntosh) size 3 or 4 laryngoscope. Alternatively, a straight (Miller) blade may be used. Once the patient has been anesthetized, the mouth is held open by the operator’s right hand. Dentures are removed. With the laryngoscope held in the operator’s left hand, the blade is passed down the right side of the tongue and into the oropharynx until the epiglottis comes into view. The correct positions of curved and straight laryngoscope blades are shown in Figure 40-4. The larynx is visualized by lifting (not pivoting) the laryngoscope blade anteriorly, thereby elevating the tongue and epiglottis. The potential views obtained at laryngoscopy are shown in Figure 40-5. The assistant on the operator’s right retracts the patient’s upper lip and passes the endotracheal tube to the operator’s right hand. The endotracheal tube is inserted through the larynx under direct vision. A distance of 21 to 23 cm from the lips for males and 20 to 22 cm from the lips for females is usually appropriate.

Figure 40.4 A, Correct position of the curved (MacIntosh) laryngoscope blade during direct laryngoscopy. B, Correct position of the straight (Miller) laryngoscope blade during direct laryngoscopy. Note that the MacIntosh blade is positioned anterior to the epiglottis in the vallecula, whereas the tip of the Miller blade is positioned posterior to the epiglottis in the laryngeal inlet.

Figure 40.5 The four grades of view of the larynx during direct laryngoscopy. Grade I, The entire glottis is seen. Grade II, Only the posterior glottis is seen. Grade III, Only the epiglottis is seen. Grade IV, The epiglottis is not seen.

(Redrawn from Cormack RS, Lehane J: Difficult tracheal intubation in obstetrics. Anaesthesia 39:1105-1111, 1984.)

If the larynx is difficult to visualize, the operator can try lifting (not pivoting) the laryngoscope blade farther, or the assistant can provide BURP (backwards, upward, rightward pressure) on the thyroid (not cricoid) cartilage. The patient’s head may be repositioned.

Intubation may be difficult when the view of the larynx is worse than grade I. Two useful maneuvers in this circumstance are (1) to stiffen the endotracheal tube with a stylet or (2) to intubate the trachea with a flexible bougie and then “railroad” a lubricated endotracheal tube over the bougie. If the latter technique is used, rotating the tube 90 degrees counterclockwise as it is advanced over the bougie at the laryngeal inlet helps to prevent the tip from catching on the arytenoid cartilages.

Confirmation of correct tube placement should include the following: (1) visualization of the tube passing through the vocal cords; (2) misting on the inside of the tube with ventilation; (3) visualization of chest movements bilaterally; (4) auscultation of the breath sounds bilaterally; (5) the presence of carbon dioxide in exhaled breath on the capnograph trace. On the chest radiograph, the tip of the endotracheal tube should be 2 to 4 cm above the carina.

Complications

Respiratory

Mild hypoxemia is reasonably common during urgent intubations performed in the ICU. If the patient’s oxygen saturation (S_Po₂) falls significantly (<90%) during attempted intubation, bag-mask ventilation should be commenced while maintaining cricoid pressure. Further attempts at intubation should be delayed until the S_Po₂ has recovered. Persistent unsuccessful attempts at intubation will lead to profound hypoxemia and even death. If intubation is not successful after three attempts (with bag-mask ventilation in between), the procedure should be abandoned, and the patient ventilated by bag-mask until the drugs have worn off, usually in about 10 minutes. If bag-mask ventilation is difficult, an oropharyngeal airway should be inserted. If problems persist, cricoid pressure should be relaxed. Failing this, emergency help should be sought from a senior clinician. Insertion of a laryngeal mask airway may be lifesaving.

Unrecognized esophageal intubation can also lead to profound hypoxemia and even death. It is essential to check that the endotracheal tube is correctly positioned, as described earlier. If a characteristic capnograph trace (see Fig. 8-13A) is not seen within two to three breaths, the tube should be removed and bag-mask ventilation commenced. Even with successful tube placement, the patient’s S_Po₂ may continue to fall for the first few breaths.

Aspiration of stomach contents may occur despite cricoid pressure. Teeth may become dislodged and the lips bruised or lacerated. Lifting, not pivoting, the laryngoscope minimizes pressure on the teeth and therefore reduces the risk of dental damage.

Cardiovascular

Hypotension is common with induction of general anesthesia because of vasodilation and loss of sympathetic tone. It should be treated with intravenous fluids and a vasopressor (e.g., phenylephrine 50 to 100 μg or metaraminol 0.5 to 1 mg). Conversely, hypertension and tachycardia may also occur. Additional opioid (e.g., fentanyl 2 to 4 μg/kg) is usually effective. An intravenous β blocker (e.g., metoprolol 2 to 4 mg) may be helpful.

INSERTION OF A DOUBLE-LUMEN ENDOTRACHEAL TUBE

A double-lumen endotracheal tube is occasionally required for differential lung ventilation following single lung transplantation or for lung isolation in cases of massive hemoptysis or bronchopleural fistula. Because of the short length of the right main bronchus (Fig. 40-6), right-sided tubes are more difficult to position and are prone to occluding the origin of the right upper lobe bronchus.⁴ Thus, a left-sided tube should be used in almost all circumstances, including selective ventilation of the right lung. For adult males, a 41F or 39F tube is usually appropriate; for adult females, a 39F or 37F tube is usually appropriate.

Figure 40.6 Position of a left-sided double-lumen endotracheal tube. A, The tube is correctly positioned. During bronchoscopy, the cuff of the bronchial lumen is just visible beyond the carina. B, The tube is inserted too far. During bronchoscopy, the bronchial cuff is not seen and the tracheal orifice appears close to the carina. C, The tube is not inserted far enough. During bronchoscopy, the bronchial cuff is seen within the trachea. RMB, right main bronchus; LMB, left main bronchus; RULB, right upper lobe bronchus.

Technique of Insertion

1. Direct laryngoscopy is performed as described earlier.

2. With the tube orientated so that the tip faces anteriorly, the tube is inserted through the laryngeal inlet.

3. The tube is rotated 90 degrees counterclockwise, and the stylet is removed, so that the tip points leftward. The tube is advanced down the trachea until it fits snugly. When correctly positioned, the tip of the endobronchial (left-sided) lumen should be in the left main bronchus, and the tip of the tracheal (right-sided) lumen should be 1 to 2 cm above the carina (Fig. 40-6A).

4. The tracheal cuff is inflated and both lungs are ventilated. The correct position of the tube is verified as described subsequently.

Assessment of Correct Tube Position

Following “blind” insertion, as described earlier, approximately 25% of double-lumen tubes are incorrectly positioned and cannot be used to ventilate the lungs selectively.⁵ Furthermore, when examined bronchoscopically, a significant proportion (15% in one study⁵) of “functioning” tubes are critically malpositioned. Thus, careful clinical and bronchoscopic assessment is indicated.

Clinical Assessment

With the tracheal and endobronchial cuffs inflated, each lung should be able to be ventilated selectively. This should be confirmed by visual inspection and auscultation. The following problems may be identified:

• Tube in too far (Fig. 40-6B). The tip of the endobronchial tube may be beyond the origin of the left upper lobe. When attempting to ventilate the left lung selectively, only the left lower lobe is ventilated. When attempting to ventilate the right lung selectively, obstruction to airflow may occur because the tracheal lumen is abutting the carina.

• Tube not in far enough (Fig. 40-6C). The bronchial cuff may herniate into the trachea. When attempting to ventilate the left lung selectively, ventilation of both lungs occurs. When attempting to ventilate the right lung selectively, obstruction to airflow may occur because of the presence of the endobronchial cuff in the distal trachea.

• Endobronchial lumen in the right side. The endobronchial lumen enters the right, rather than the left, main stem bronchus. When attempting to ventilate the left lung selectively, partial ventilation of the right lung occurs (due to obstruction of the origin of the right upper lobe bronchus). When attempting to ventilate the right lung selectively, ventilation of the left lung occurs.

Bronchoscopic Assessment

The fiberoptic bronchoscope is passed down the tracheal lumen. With correct positioning, the carina and right main bronchus should be clearly visualized. The origin of the left main bronchus is obscured by the endobronchial lumen, but the proximal margin of the (blue) endobronchial cuff should be just visible (see Fig. 40-6A). The bronchoscopic findings when the tube has been advanced too far or not far enough are shown in Figure 40-6B and C, respectively).

If the endobronchial lumen is identified as being in the right main stem bronchus, the tube should be withdrawn 5 to 7 cm until the endobronchial tip is in the trachea. The bronchoscope is then advanced through the bronchial lumen into the left main stem bronchus, and the endotracheal tube is railroaded over the bronchoscope into the left side.

Bronchial Blockers

As an alternative to a double-lumen endotracheal tube, a single-lumen tube and a bronchial blocker may be used for lung isolation. A brief description of one of these devices is provided in Chapter 26.

FIBEROPTIC LARYNGOSCOPY AND BRONCHOSCOPY

Fiberoptic laryngoscopy is usually indicated to facilitate tracheal intubation in patients who are known to be difficult to intubate by direct laryngoscopy. The indications for bronchoscopy in the ICU are listed in Table 40-4. Relative contraindications to bronchoscopy include severe coagulopathy, pulmonary arterial hypertension, and bronchospasm. In general, diagnostic bronchoscopy should be avoided in patients with severely impaired gas exchange because it may cause further respiratory embarrassment. By contrast, therapeutic bronchoscopy—for instance, for treating lobar collapse due to mucus plugging—may significantly improve gas exchange.

Table 40-4 Indications for Fiberoptic Bronchoscopy in the ICU

Diagnostic

Diagnosis of pneumonia

Diagnosis of bronchopleural fistula

Identification of a bleeding site

Identification of injury following airway trauma

Therapeutic

Relief of mucus plugging

Removal of foreign body

Identification of the correct placement of double-lumen endotracheal tube

Lung isolation to treat massive hemoptysis or bronchopleural fistula

Placement of fibrin glue to treat bronchopleural fistula

ICU, intensive care unit.

All patients undergoing fiberoptic laryngoscopy or bronchoscopy should be monitored by pulse oximetry, blood pressure cuff or intraarterial cannula, ECG, and capnography. A clinician should be dedicated to ensuring that the patient’s vital signs remain adequate throughout the procedure.

Awake Fiberoptic Laryngoscopy and Intubation

Fiberoptic laryngoscopy may be performed via the oral or the nasal route; in most circumstances the choice of technique depends on the experience of the operator. Nasal intubation should be avoided in coagulopathic patients.

Patients should be prepared by being given mild intravenous sedation (see earlier material) and an antisialagogue (e.g., glycopyrrolate 200 μg intravenously). If nasal intubation is planned, vasoconstrictive spray or drops (e.g., 1% phenylephrine or 0.1% xylometazoline) should be applied to each nostril a few minutes beforehand. An endotracheal tube (0.5 to 1 size smaller than usual) should be placed in warm sterile water to soften it. Supplemental oxygen should be administered throughout the procedure.

Topical Anesthesia

Numerous techniques may be used for topical anesthesia of the airway. One approach for orotracheal intubation is described here. First, 5 ml of 4% lidocaine is administered via a nebulizer. Next, a 22-gauge intravenous cannula with an injection port is connected to oxygen tubing. Five ml of 4% lidocaine is injected into the injection port of the cannula while the oxygen supply is running at 2 to 4 l/min. This creates a fine jet of lidocaine, which is directed over the base of the patient’s tongue and deep into the oropharynx. Injection should be timed with inspiration and the patient instructed not to swallow. Following this, topical anesthesia should be sufficient to allow the posterior pharyngeal wall to be stimulated by a tongue depressor without eliciting a gag reflex. Finally, during fiberoptic laryngoscopy, a further 2 ml of 4% lidocaine is injected through the working port of the bronchoscope directly onto the vocal cords and into the trachea. Injection should be timed with inspiration.

Technique of Awake Orotracheal Fiberoptic Laryngoscopy and Intubation

The softened endotracheal tube is loaded onto the bronchoscope. The patient should be in a semirecumbent position. Oropharyngeal secretions should be suctioned. The operator may stand in front of or behind the patient (as described earlier). The operator should familiarize himself or herself with the movements of the bronchoscope; in particular, anteflexion and retroflexion are performed by moving the control lever, and leftward and rightward motions are performed by turning the shaft of the scope.

The patient is asked to open his or her mouth and protrude the tongue. An assistant grasps the tongue and pulls it gently outward, holding it with gauze. The operator holds the scope 12 to 15 cm from the tip (so as not to have to reposition the grip before the trachea is entered). The bronchoscope is inserted into the patient’s mouth in the midline. As the bronchoscope is anteflexed over the base of the tongue, first the uvula (Fig. 40-7A) and then the epiglottis (Fig. 40-7B) should be seen. If the epiglottis is in contact with the posterior pharyngeal wall, pulling on the tongue and elevating the mandible opens the airspace. The bronchoscope is advanced under the epiglottis until the larynx (Fig. 40-7C) comes into view. Anteflexion should be maintained as the larynx is approached, but to advance the bronchoscope through the vocal cords (Fig. 40-7D), retroflexion is required so the tip of the bronchoscope can be passed over the arytenoid cartilages. The bronchoscope is advanced into the trachea until the carina is seen. An assistant then railroads the endotracheal tube over the bronchoscope and into the trachea. The tip of the tube may catch on the arytenoid cartilages; twisting the tube as it is advanced usually solves this problem. The tube is positioned 2 to 4 cm above the carina under bronchoscopic guidance. The bronchoscope is withdrawn and, once a characteristic capnograph trace is seen, the patient is connected to the ventilator, and additional sedation is given as required.

Figure 40.7 Views obtained during orotracheal fiberoptic laryngoscopy with the operator standing behind the patient. See text for details.

It is very easy for the operator to become disorientated during fiberoptic laryngoscopy. Always keeping to the midline and making only small movements of the bronchoscope minimizes this problem. If the operator becomes disorientated, the scope should be withdrawn into the mouth and the procedure repeated. A special oropharyngeal airway (e.g., Ovassapian and Berman), through which the bronchoscope can be passed, may be used to aid laryngoscopy.

Fiberoptic Bronchoscopy

Fiberoptic bronchoscopy may be performed in intubated or extubated patients. In extubated patients, the techniques of sedation and airway anesthesia just described apply. An additional injection of 4% lidocaine through the working port of the bronchoscope may be needed to anesthetize the distal airways. In extubated patients with respiratory distress, fiberoptic bronchoscopy can lead to a precipitous decline in respiratory function necessitating immediate endotracheal intubation; appropriate equipment should be immediately available. For intubated patients, general anesthesia and neuromuscular paralysis are indicated.

Bronchoscopes vary in size but may have an external diameter up to 6 mm. To accommodate a 6-mm bronchoscope—and still allow effective ventilation—an 8-mm (or larger) internal diameter endotracheal tube should be used. If a large bronchoscope is used with a small endotracheal tube, ventilation may be inadequate and gas trapping, leading to dynamic lung hyperinflation (see Chapter 20), can occur. If significant hypoxemia (S_ao₂ <90%) or hypotension develops, the bronchoscope should be withdrawn until the patient has recovered.

A catheter mount with a diaphragm, through which the bronchoscope is passed, may be attached to the endotracheal tube to prevent excessive gas leakage. The patient should be ventilated with 100% oxygen for at least 5 minutes before starting. As with fiberoptic laryngoscopy, the operator may stand behind or in front of the patient.

Bronchoscopic examinations performed in the ICU are targeted studies, and complete examination of all of the subsegmental bronchi is not usually performed. However, the operator must be able to navigate to specific lobes of the lung, so it is important to be able to recognize standard bronchoscopic landmarks (Fig. 40-8). When obtaining microbiologic samples, the bronchoscope should be navigated into the bronchus of the target lobe and the tip wedged as distally as possible. To avoid contamination by the large airways, the suction port should not be used until samples have been obtained. If quantitative culture is planned, either broncho-alveolar lavage or protected specimen brush samples should be obtained (see Chapter 35). For a broncho-alveolar lavage, 50 to 150 ml of sterile saline should be instilled, with at least 50% of the volume aspirated into the specimen container.⁶ For nonquantitative culture, a bronchial washing, in which 10 ml of saline is instilled, is adequate.

Figure 40.8 Bronchoscopic anatomy. Part I, The major bronchoscopic landmarks. Part II, Bronchial anatomy is shown diagrammatically. The corresponding positions between I and II are labeled A to I.

PERCUTANEOUS TRACHEOTOMY

The indications for tracheotomy are outlined in Chapter 29. Percutaneous insertion is at least as safe as open surgical placement⁷ and has the advantage of being able to be performed rapidly at the bedside. A number of techniques have been described⁸; only the percutaneous dilational method is discussed here.

Patients who have undergone a previous tracheotomy, are known to be difficult to intubate, or have unfavorable anatomy (e.g., “bull” neck, goiter, or tracheal distortion) are unsuitable for a percutaneous approach and should undergo surgical tracheotomy. Coagulopathy should be corrected before proceeding. Because a tracheotomy is performed to facilitate ventilatory weaning, it is not appropriate in patients with severely impaired gas exchange.

Knowledge of the anatomy of the larynx and trachea is essential. In particular, the operator should be able to accurately identify the surface landmarks of the thyroid cartilage, the cricoid cartilage, and the tracheal rings (see Fig. 40-3). Table 40-5 lists the equipment that should be available in the patient’s bed space before proceeding. For adult males, a 9-mm internal diameter tracheotomy tube is usually appropriate; for adult females, an 8-mm tube is usually appropriate. In the first instance, a cuffed, nonfenestrated tube should be inserted (see Chapter 29). For obese patients (in whom percutaneous tracheotomy is commonly unsuitable), long tubes with adjustable flanges are available.

Table 40-5 Equipment for Percutaneous Tracheotomy

Equipment for endotracheal intubation (see Table 40-2)

Fiberoptic bronchoscope

Two high-pressure suctions: (1) oropharynx; (2) suction port of the bronchoscope

Percutaneous tracheotomy kit

Tracheotomy tubes (intended size + one size smaller)

Lidocaine with epinephrine 1:200,000

Syringes and needles for infiltration of local anesthesia

Sterile catheter mount

Sterile drapes

Sterile gloves and gowns (two sets)

Surgical masks

Capnography

Sterile dissection forceps, clamp, scalpel blade, and scissors

Adequate lighting

Surgical diathermy (optional)

The procedure is elective and should be performed within office hours. The patient should fast for 6 hours and should have received a proton pump inhibitor (e.g., omeprazole 40 mg intravenously) at least 30 minutes beforehand. Prior to starting, the nasogastric tube should be aspirated and the patient should be fully ventilated with 100% oxygen using the pressure control mode. Anesthesia should be induced with a hypnotic (e.g., a propofol bolus of 0.5 mg/kg followed by an infusion of 3 to 6 mg/kg/hr); an opioid (e.g., fentanyl 2 to 4 μg/kg), and a nondepolarizing neuromuscular blocker (e.g., vecuronium 0.1 mg/kg).

Technique

1. Positioning and local anesthesia. The patient should be positioned flat, with a roll behind the shoulders (not head) to extend the neck. The neck should be cleaned with 2% aqueous chlorhexidine solution and sterile drapes applied. Local anesthetic (e.g., 5 to 10 ml lidocaine 1% with epinephrine 1:200,000) should be infiltrated into the skin over the planned insertion site, taking care not to puncture the endotracheal tube cuff.

2. Incision and dissection. A transverse incision 1.5 to 2 cm long should be made in the midline, 1 cm above the suprasternal notch over the proximal trachea. Blunt dissection should be performed down to the pretracheal fascia using fine curved forceps.

3. Withdrawal of the endotracheal tube. Direct laryngoscopy is performed using a standard MacIntosh laryngoscope. The endotracheal tube cuff is deflated and the tube withdrawn until the cuff is just above the laryngeal inlet. The cuff is reinflated with 20 to 30 ml of air until the leak stops. The endotracheal tube is held in position to prevent it from herniating into the pharynx. The operator should manipulate the laryngoscope and endotracheal tube, and an assistant should inflate and deflate the cuff. Next, the fiberoptic bronchoscope is inserted into the endotracheal tube and advanced until the tip of the bronchoscope is just inside the endotracheal tube and a view of the first few tracheal rings is obtained.

4. Needle and wire placement. The needle (with cannula) is inserted through the incision into the trachea (Fig. 40-9A). Air should be freely aspirated through the syringe, and looking through the bronchoscope, the needle should be seen entering the trachea between the 11 and 1 o’clock positions. If the needle enters the trachea too laterally or above the level of the first tracheal cartilage (typically passing through the cricotracheal membrane), it should be withdrawn and reinserted correctly. The cannula is then advanced into the trachea and the needle is withdrawn. The guide wire is inserted through the hub of the cannula into the trachea, and the cannula is removed. First a dilator, then a stiffener is advanced over the guide wire (Fig. 40-9B).

5. Track dilation and insertion of tracheotomy. The track is dilated as shown in Figure 40-9C. The tracheotomy tube (and its introducer) is inserted over the guide wire plus stiffener (see Fig. 40-9D) and advanced into the trachea. This sometimes requires considerable pressure and is associated with a sudden “give” as the tracheotomy tube enters the trachea.

6. Checking the position of the tracheotomy tube. The introducer and stiffener are withdrawn, leaving the tracheotomy tube and guide wire in the trachea. The bronchoscope is removed from the endotracheal tube and inserted into the tracheotomy tube to confirm its correct placement in the trachea. The guide wire is removed and the tracheotomy tube is connected to the ventilator. The chest should be inspected and auscultated and the capnograph examined to confirm the adequacy of ventilation. The neck and chest wall should be palpated for surgical emphysema. The tracheotomy is sutured or taped in place and the endotracheal tube is removed. A chest radiograph should be obtained to ensure that the tube is correctly positioned and the lungs are fully inflated.

Figure 40.9 Percutaneous tracheotomy. The stages of percutaneous dilational tracheotomy using a Blue Rhino (Cook Critical Care, Bloomington, IL) percutaneous tracheotomy set with a single tracheal dilator. A, The needle has been inserted into the trachea between the first and second tracheal rings. B, The guide wire and introducer/stiffener have been advanced into the trachea. C, The dilator has been advanced over the guide wire and introducer so as to dilate the track. D, The tracheotomy tube has been inserted over the introducer and guide wire and into the trachea. See text for details.

Complications

Bleeding can occur during blunt dissection. It usually stops with pressure or the application of (1:10,000) epinephrine-soaked swabs. Occasionally, a bleeding vein must be tied off. Surgical diathermy, if available, may be very helpful. Perforation of the posterior tracheal wall can lead to a tracheoesophageal fistula, which may not be apparent immediately but may present later as pneumonia. Avoidance of this complication is the main indication for performing the technique under bronchoscopic guidance.

Displacement of the tracheotomy tube into the paratracheal tissues results in problems with ventilation and the development of subcutaneous emphysema in the neck. If this occurs during insertion, the tracheotomy tube should be removed and the orotracheal tube advanced into the distal trachea under bronchoscopic guidance. If displacement occurs later and the patient is ventilator dependent, the tracheotomy tube should be removed and immediate orotracheal intubation performed. If the patient is not ventilator dependent, it may be possible to intubate the trachea via the tracheotomy wound, using a bronchoscope and then railroading the tracheotomy tube back into the trachea. This is not usually possible within the first 24 hours because the track will not be well formed. A persistent air leak despite adequate inflation of the pilot balloon suggests partial displacement of the tracheotomy tube. A chest radiograph should be obtained and bronchoscopy performed to verify the position of the tube. It may be possible to railroad the tracheotomy tube back into the trachea over a bronchoscope.

Gas exchange is commonly impaired for several hours following tracheotomy. There may be atelectasis resulting from hypoventilation or lobar collapse resulting from blood clots and mucus plugging. The treatment is positive end-expiratory pressure and aggressive tracheal toilet.

PLEURAL DRAINAGE

Pleural drains are inserted to evacuate air or fluid from the pleural space.⁹ Small-bore tubes (10F to 14F) may be used for pleural effusions; medium-bore tubes (20F to 28F) for pneumothoraces; large-bore tubes (>28F) for hemothoraces. Fine- and medium-bore tubes, up to about 24F, can be inserted by using a Seldinger technique. Large tubes should be inserted via blunt dissection into the pleural space (tube thoracostomy). Life-threatening tension pneumothoraces should be treated by needle thoracocentesis followed by tube thoracostomy. Apart from emergency needle thoracocentesis, full sterile precautions should always be observed.

Needle Thoracocentesis

Needle thoracocentesis may be performed using a large-bore (14- or 16-gauge) intravenous cannula connected to a syringe. Anterior or lateral approaches may be used. In the anterior approach, the cannula is inserted into the second intercostal space in the mid clavicular line. The needle should be perpendicular to the skin and should enter the intercostal space immediately above the superior border of the third rib. Entry into the pleural space is identified by aspirating air into the syringe. If the pleural cavity is under tension, a hiss of escaping air is heard when the syringe is disconnected from the cannula.

Seldinger Technique

To perform the Seldinger technique, a kit containing all the necessary components, including 10F to 24F tubes, should be used. The skin and subcutaneous tissues are infiltrated with local anesthetic (5 to 10 ml lidocaine with epinephrine 1:200,000). The needle is inserted over the superior border of the rib (to avoid the neurovascular bundle) and into the pleural space, using the landmarks described subsequently. A guide wire is inserted into the hub of the needle and advanced into the pleural space. The needle is removed and the track enlarged by a dilator. The tube is advanced over the guide wire into the pleural space. The guide wire is removed and the tube is connected to an underwater seal. A chest radiograph should be obtained.

Technique of Thoracostomy Using Tubes 24F or Larger

1. Positioning and preparation. The patient is positioned with the hand on the operative side placed behind the head. This widens the intercostal spaces and gives the operator room to work. The head of the bed may be slightly elevated. In conscious patients, intravenous sedation and analgesia should be administered.

2. Landmarks and local anesthesia. The fourth or fifth intercostal space is identified within “the safe triangle” (Fig. 40-10). In conscious patients, local anesthetic (10 ml lidocaine 1% with epinephrine 1:200,000) is infiltrated into the skin and tissues down to the level of the rib. Intercostal nerve blocks (see Chapter 12) may be performed to provide additional analgesia.

3. Incision and dissection. The skin incision should be parallel to the rib and 1.5 to 2 cm long. Blunt dissection is performed down to the rib. Closed forceps are rolled over the superior edge of the rib to avoid damaging the neurovascular bundle (Fig. 40-11). Blunt dissection is continued until the pleura is penetrated. The track should be explored with a finger to ensure that there are no underlying organs or pleural adhesions. A mattress suture using 0 or 1 silk is placed for wound closure.

4. Insertion of the drain. The trocar is withdrawn 5 cm and the tube gently inserted through the track into the chest cavity. The trocar can be used to guide the tube apically (for air) or basally (for fluid). The tube is clamped and secured with a stay suture using 0 or 1 silk.

5. Underwater seal and suction. The tube is attached to an underwater seal and the clamp released. A sterile dressing is applied to the wound.

Figure 40.10 The “safe triangle” for insertion of an intercostal drain. The safe triangle is bounded anteriorly by the lateral border of the pectoralis major muscle, posteriorly by the anterior border of the latissimus dorsi muscle, and inferiorly by a horizontal line at the level of the nipple.

(Redrawn from Laws D, Neville E, Duffy, J, et al. BTS guidelines for the insertion of a chest drain. Thorax 58(suppl 2):ii53-ii59, 2003.)

Figure 40.11 Cross-section of the intercostal space. A curved forceps is seen passing just superiorly to a rib into the intercostal space. The parietal pleura has been penetrated and the lung has fallen away. The intercostal bundles (artery, vein, and nerve) are seen in cross-section inferior to the ribs.

A chest radiograph should be obtained to confirm the position of the thoracostomy tube and diagnose any residual pneumothorax. Occasionally, a thoracostomy tube lies within a pulmonary fissure, in which case it may be ineffective and have to be reinserted. Suction is not indicated following drainage of fluid collections and is not usually necessary for pneumothoraces. Low-pressure suction (10 to 20 cm H₂O, or 7.5 to 15 mmHg, or 1 to 2 kPa) may be applied following drainage of a pneumothorax if the chest radiograph shows that the lung has not fully reexpanded.

Complications of Tube Thoracostomy

Complications include pain, hemorrhage (from the intercostal vessels or lung), bronchopleural fistula, and infection. Ongoing pain may significantly inhibit the patient’s ability to take deep breaths and cough.

ARTERIAL CANNULATION

Arterial cannulation is performed for the purposes of continuous blood pressure monitoring and arterial blood sampling. The radial artery in the wrist is the preferred site of cannulation because it is superficial, remote from nerves, relatively immobile, and (as the result of collateral supply from the ulnar artery) its occlusion does not usually cause distal ischemia. The brachial and femoral arteries may be used if the radial arteries are not available.

Technique of Radial Arterial Cannulation

Radial arterial cannulation is performed as follows.¹⁰

The radial pulse is palpated between the distal radius and the flexor carpi radialis tendon. Prior to cannulation, the perfusion of the hand should be checked using a modified Allen test. The operator occludes the radial and ulnar arteries at the wrist while the patient clenches his or her fist. As the fist is unclenched, the operator releases pressure over the ulnar artery. Color should return to the hand within 5 seconds. Delayed or incomplete return of color suggests inadequate ulnar collateral flow, and an alternative site of arterial cannulation should be considered.

The wrist is positioned and stabilized in mild dorsiflexion using a wrist board or roll. Once positioned, the wrist is cleaned with 2% chlorhexidine and sterile drapes are applied. The operator should wear sterile gloves. In conscious patients, local anesthetic (1 to 2 ml lidocaine 1% without epinephrine) should be infiltrated over the insertion site using a fine (25-gauge) needle. A 20-gauge, 5-cm cannula is suitable for cannulation. A direct (cannula over needle), transfixion or Seldinger (cannula over wire) insertion technique may be used, as shown in Figs. 40-12, 40-13, and 40-14. The cannula should be connected to a continuous flushing system (which need not be heparinized) and the waveform transduced. The cannula is secured—preferably by a suture—and the insertion site covered by a clear dressing. The cannula should be clearly labeled “arterial” so as to avoid inadvertent drug injection. At the completion of the procedure, distal perfusion should be checked.

Figure 40.12 Direct technique of arterial cannulation. A, The stylet and catheter are passed through the skin and subcutaneous tissue. B, Once the stylet is within the artery lumen its advance is halted. C, The stylet is rotated through 180 degrees. D, That allows the cannula to be more easily advanced into the artery. E, The stylet is then withdrawn fully.

(Redrawn from Latto IP, Ng WS, Jones PL, et al. Percutaneous Central Venous and Arterial Catheterization, ed. 3. Philadelphia, WB Saunders, 2000.)

Figure 40.13 Transfixion technique of arterial cannulation. A, The stylet and catheter are passed through the skin and subcutaneous tissue. B, The stylet and catheter are advanced through the artery. C, The stylet is removed, and the catheter is withdrawn slowly until blood is aspirated. D, Saline is injected down the catheter into the artery. E, While the saline is being injected, the catheter is advanced into the artery.

(Redrawn from Latto IP, Ng WS, Jones PL, et al. Percutaneous Central Venous and Arterial Catheterization, ed. 3. Philadelphia, WB Saunders, 2000.)

Figure 40.14 The Seldinger technique of arterial cannulation. A, A needle is advanced through the skin and subcutaneous tissue. B, When the needle penetrates the artery, blood is aspirated and the needle is held steady. C, A guide wire is advanced into the hub of the needle and into the lumen of the artery. D, The needle is withdrawn, leaving the guide wire in place. E, A catheter is advanced over the guide wire into the artery. F, Finally, the guide wire is removed.

(Redrawn from Latto IP, Ng WS, Jones PL, et al: Percutaneous Central Venous and Arterial Catheterization, ed. 3. Philadelphia, WB Saunders, 2002.)

Complications in Arterial Cannulation

Complications in arterial cannulation include air embolization, hematoma, arterial insufficiency, and infection. Even very small volumes of air can, if injected intraarterially, cause distal ischemia. If there are signs of inadequate perfusion, the cannula should be removed. Infection of arterial cannulas is uncommon. In one study, the incidence of exit-site and blood stream infections were 1.17/1000 catheter-days and 0.59/1000 catheter-days, respectively, with the incidence of both types of infection being higher with femoral than with radial cannulation.¹¹

CENTRAL VENOUS CATHETERIZATION

Central venous catheterization is indicated for administering drugs—particularly vasoactive or irritant drugs—and for pressure monitoring, blood sampling, renal replacement therapy, and delivery of intravenous nutrition.

Choice of Vein

Sites of insertion include the internal jugular, subclavian, peripheral, and femoral veins. The right internal jugular is the most commonly used site in patients undergoing cardiac surgery. The internal jugular vein is relatively easy to cannulate, is well visualized with ultrasound imaging, is compressible in the event of bleeding, has a low incidence of acute complications, and is accessible during surgery. However, in conscious patients, central venous catheters (CVCs) at this site can cause discomfort during movement. Also, tensing of the sternomastoid muscle creates difficulties during insertion. The subclavian vein is the preferred site for long-stay ICU patients because it is more comfortable for the patient and is associated with a reduced incidence of infection compared with the internal jugular vein or femoral sites.¹² However, the subclavian site is associated with a higher rate of acute complications— particularly pneumothorax—than are other sites, and CVCs are more technically demanding to insert in this location. The femoral vein is a good choice for temporary dialysis catheters in sedated patients because it is associated with excellent flow characteristics and, like the internal jugular vein, is compressible in the event of bleeding. The disadvantages of the femoral site include unreliable central venous pressure recordings, a high rate of infection,¹² limited patient mobility, and the inability to obtain a superior vena cava oxygen saturation. Peripherally inserted central venous catheters (PICCs) are suitable for patients who require long-term antimicrobial therapy. They cause few acute life-threatening complications, have low infection rates, and require a simple insertion technique. However, PICCs are unable to be positioned centrally in 25% to 40% of cases¹³; in these cases, it may not be possible to aspirate blood from the lumens so the incidence of infectious and thrombotic complications rises (see subsequent material).

General Comments on Technique

Preparation

All CVCs should be inserted using full sterile precautions. Skin should be cleaned with 2% aqueous chlorhexidine (as opposed to 70% alcohol or 10% povidone-iodine),¹⁴ and the operator should don a mask, sterile gloves, and a sterile gown. In conscious patients, local anesthetic (lidocaine 5 to 10 ml with epinephrine 1:200,000) should be infiltrated over the insertion site.

Localization of the Vein

The operator should have a thorough knowledge of the anatomy of the vein and its relationship to other structures. Traditionally, venipuncture has been guided by surface landmarks, but over the past decade there has been increasing use of real-time ultrasound imaging to guide needle placement. A metaanalysis of randomized trials demonstrated that ultrasound-guided internal jugular CVC placement resulted in a higher success rate, a shorter time to cannulation, and a reduced incidence of complications than did the landmark method.¹⁵ Thus, if available, ultrasound imaging should be used to guide catheterization at this site.

As the needle is advanced toward the vein, gentle negative pressure should be applied to the syringe. It is common for blood to be aspirated only during withdrawal of the needle.

Catheter Insertion

All CVCs should be inserted using a Seldinger (a catheter over a wire) technique.¹⁶ Once blood is freely aspirated, the guide wire is inserted into the hub of the needle (or through the hub of the syringe, depending on the kit) and advanced into the vein. If there is any concern that the guide wire is intraarterial, an 18-gauge single-lumen catheter—included in most CVC kits—can be inserted over the wire without dilating the track and then transduced to exclude the possibility of this complication.

Once the operator is satisfied the guide wire is correctly positioned, a small skin cut is made at the insertion site, and the track is enlarged using a dilator. Dilators are stiff and can cause vascular damage; thus, they should be inserted only 3 to 4 cm deep into the skin. Once the track has been dilated, the catheter is advanced over the guide wire into the vein. The operator should hold the guide wire throughout this maneuver to ensure that it is not lost intravascularly.

Position of the Catheter Tip

A chest radiograph should be obtained after placement of all CVCs (except femoral catheters) to assess the position of the catheter and to rule out a complication such as pneumothorax or hemothorax. The tip of a CVC should lie in the superior vena cava outside the pericardium. On the chest radiograph, the tip of the catheter should lie outside the angle between the right main bronchus and the trachea.¹⁷ CVCs that appear kinked or curved into the wall of a vein on the chest radiograph may cause perforation and should be repositioned.

Internal Jugular Vein Cannulation

The internal jugular vein usually, but not always, lies lateral to the carotid artery and deep to the body of sternomastoid muscle in the neck (Fig. 40-15). A middle approach to the internal jugular vein is described here.

Figure 40.15 Anatomy of the jugular vein. The internal jugular vein is seen lateral to the common carotid and deep to the sternomastoid muscle (which has been removed on the right for clarity).

(Redrawn from Willeford KL, Reitan JA: Neutral head position for placement of internal jugular vein catheters. Anaesthesiology 49:202-204, 1994.)

1. Positioning and landmarks. The patient is placed in a 15-degree head-down position with the arms by the sides and the head turned slightly away from the operative side. A small roll may be placed horizontally behind the shoulders. The carotid artery is palpated at the level of the cricoid cartilage, which is the approximate midpoint between the sternal notch and the mastoid process.

2. Ultrasound technique. The transducer is positioned just below level of the cricoid cartilage over the sternomastoid muscle. For right-sided cannulation, the operator should hold the transducer in the left hand and the needle in the right hand. The depth should be set to about 4 cm. The probe is moved medial to lateral to visualize first the carotid artery and then the jugular vein in cross section (Fig. 40-16). The artery is identified by the fact that it is smaller and more medial than the vein, is incompressible, and pulsates. The transducer is centered on the vein and the needle positioned proximally to the transducer. The needle can be “bounced” on the skin to confirm that it overlies the vein. The needle is inserted 45 degrees to the skin, cephalad to the ultrasound transducer.

3. Anatomical technique. The needle is inserted just lateral to the carotid artery. It should be angled at about 45 degrees to the skin and directed toward the patient’s ipsilateral nipple as if it were projected onto the back (Fig. 40-17). As the deep cervical fascia is penetrated, a “give” may be appreciated. The needle does not usually have to be advanced more than 3 cm deep to the skin. Failure to locate the vein after three passes is an indication to use ultrasound guidance or insertion at another site.

4. Catheter insertion. A right-sided catheter should be inserted 12 to 14 cm; a left-sided catheter should be inserted 14 to 16 cm.

Figure 40.16 Ultrasound image of the internal jugular vein (V) and the common carotid artery (A) at the level of the cricoid cartilage. A, The vein is uncompressed. B, The ultrasound transducer is compressing the vein.

Figure 40.17 Technique of internal jugular vein cannulation. See text for details.

(Redrawn from Latto IP, Ng WS, Jones PL, et al: Percutaneous Central Venous and Arterial Catheterization, ed. 3. Philadelphia, WB Saunders, 2000.)

Subclavian Vein Cannulation

The relevant anatomy of the subclavian vein is shown in Figure 40-18. An infraclavicular approach to the vein is described here.

Figure 40.18 Anatomy of the subclavian vein. The relationship of the right subclavian vein to the clavicle, first rib, scalenus muscle, and the subclavian artery is shown.

(Redrawn from Latto IP, Ng WS, Jones PL, et al: Percutaneous Central Venous and Arterial Catheterization, ed. 3. Philadelphia, WB Saunders, 2002.)

1. Positioning and landmarks. The patient is placed 15 degrees head-down, with the arms alongside the body and the head turned slightly away from the operative side. A small roll may be placed vertically between the scapulae. The midpoint of the clavicle and the suprasternal notch are identified.

2. Venipuncture. The needle is inserted 1 cm below the lower border of the clavicle, just lateral to the midclavicular point and directed toward the suprasternal notch (Fig. 40-19). The needle is initially angled at about 20 to 40 degrees to the horizontal so it passes just underneath the clavicle. If the angle is too steep, the needle may penetrate the pleura; if the angle is too shallow, the needle will not pass under the clavicle. Once under the clavicle, the angle is reduced to between 0 and 10 degrees so that the needle passes between the clavicle and the first rib. The needle should be advanced to a distance of about 4 cm and then slowly withdrawn. If the needle fails to enter the vein, it should be directed slightly more cephalad.

3. Catheter insertion. A right-sided catheter should be inserted 12 to 14 cm; a left-sided catheter should be inserted 14 to 16 cm.

Figure 40.19 Technique of subclavian vein cannulation. The needle is initially at 20° to 40° to the horizontal. Once it has passed under the clavicle, the needle is inclined 0° to 10°.

(Redrawn from Latto IP, Ng WS, Jones PL, et al: Percutaneous Central Venous and Arterial Catheterization, ed. 3. Philadelphia, WB Saunders, 2000.)

If the gap between the first rib and the clavicle is very narrow, it may be very difficult to pass the needle between them or the needle and guide wire may pass through but it may be impossible to advance the dilator or CVC. This problem is minimized by ensuring that the needle is not inserted too medially (i.e., that it is inserted just lateral to the midclavicular line).

Femoral Vein Cannulation

1. Positioning and landmarks. A roll is placed behind the patient’s buttocks and the leg is slightly abducted at the hip. The pulsations of the femoral artery should be palpated at the level of the inguinal ligament, which runs between the anterior superior iliac crest and the pubic tubercle (Fig. 40-20). The vein usually lies 1 to 1.5 cm medial to the artery.

2. Venipuncture. The needle should be inserted 2 to 3 cm below the inguinal ligament (see Fig. 40-20) and angled at 45 to 60 degrees to the skin so that the vein is entered just distal to the ligament. The needle should be advanced in a sagittal direction (i.e., vertically), not angled toward the umbilicus.

Figure 40.20 A, Anatomy of the femoral vein. B, Technique of femoral vein cannulation. See text for details.

(Redrawn from Latto IP, Ng WS, Jones PL, et al: Percutaneous Central Venous and Arterial Catheterization, ed. 3. Philadelphia, WB Saunders, 2000.)

Peripheral Vein Cannulation

PICCs are usually inserted into a vein in the antecubital fossa. Of the two subcutaneous veins in the antecubital fossa, the basilic vein (medial) is preferred because using the cephalic vein (lateral) may cause the catheter to catch at the shoulder where the vein pierces the clavipectoral fascia. The insertion technique depends on the kit used. A Seldinger technique utilizing a “peel-away” introducer cannula is described here.

1. Positioning and landmarks. The patient should be supine in a semirecumbent position with the arm abducted to about 45 degrees. The lumens of the PICC should be flushed with saline and the approximate length between the insertion site and the right atrium measured (a disposable tape measure is included in many kits). A tourniquet is applied to the patient’s arm, and the basilic vein is identified.

2. Venipuncture and insertion of introducer. Venipuncture is performed using a needle and syringe. A guide wire is inserted 5 to 10 cm into the vein. The needle is withdrawn and the tourniquet is released. A small cut is made in the skin at the insertion site. A peel-away introducer sheath and dilator is advanced into the vein. The guide wire and dilator are removed. Back bleeding through the introducer is allowed for 1 to 2 seconds, and then the vein is occluded proximally.

3. Catheter insertion. The PICC is inserted into the introducer sheath and advanced an appropriate distance into the vein. If the catheter will not advance beyond the shoulder, it may be useful to abduct the patient’s arm to 90 degrees or to turn the head away from the operative side. The introducer sheath is withdrawn from the vein and peeled apart so it can be removed.

Complications

Complications ^12,^18,¹⁹ involved with CVCs may be mechanical, thrombotic, or infectious. Infectious complications are discussed in Chapter 35. The most common mechanical complications are arterial puncture, hematoma, hemothorax, and pneumothorax (Table 40-6). The likelihood of complications is determined by the insertion site, the operator’s experience, and patient factors, such obesity, coagulopathy, and anatomic abnormalities. The incidence of complications increases greatly when the number of needle passes exceeds three.²⁰

Table 40-6 Frequency of Mechanical Complications of Central Venous Catheterization According to Route of Insertion

Some complications, such as hematoma, arterial puncture, air embolism, guide wire or catheter embolization, thrombosis, and infection, can occur at all insertion sites. Arrhythmias and pericardial tamponade can occur when catheters are inserted at all sites except the femoral vein. Arrhythmias commonly result from atrial or ventricular irritation caused by the guide wire during catheter insertion. They are usually of nuisance value only. Tamponade that occurs shortly after insertion is likely to be due to trauma caused by the guide wire. Late tamponade occurs usually because of movements of the catheter tip with changes in the arm or head position. Ensuring that the tip of the catheter lies outside the pericardial reflection (see earlier material) and that it is well secured minimizes the problem.

To prevent air embolism during CVC insertion, subclavian and internal jugular catheters should be flushed while the patient is in the head-down position. If air embolism is suspected, the patient should be placed head-down in the left lateral position (to prevent air from entering the right ventricular outflow tract). Oxygen should be administered at 100%, and the catheter should be aspirated in an attempt to remove air from the right heart.

The following site-specific complications can occur.

Complications of Internal Jugular Cannulation

Carotid arterial puncture is common (see Table 40-6). Puncture of the subclavian, vertebral, or thyroid vessels can also occur. Usually the problem is easily managed by firm compression over the site. Rarely, a large hematoma forms, potentially causing airway obstruction. Stroke is also possible due to dislodgment of carotid atheroma or carotid compression resulting from a hematoma. Pneumothorax is uncommon with the technique described, but it can occur when a low approach is used. Damage to the cervical sympathetic chain and injury to the phrenic, vagus, and recurrent laryngeal nerves is also possible.²¹^–²³

Occasionally, the tip of the catheter is seen on the chest radiograph to lie in the subclavian vein rather than in the superior vena cava. If the catheter is to be used for only a few days, it does not have to be repositioned. However, pressure recordings may be unreliable and the incidence of thrombosis may be increased.

PULMONARY ARTERY CATHETERIZATION

The use of pulmonary artery catheters (PACs) is described in Chapter 8. Contraindications to pulmonary artery catheterization are listed in Table 40-7. Prior to floating a PAC, an introducer sheath must be inserted into a central vein. The internal jugular site is the preferred site because obstruction between the first rib and clavicle (see earlier material) can occur at the subclavian site. Pulmonary artery catheterization involves the following steps.

Table 40-7 Contraindications to Pulmonary Artery Catheterization

Absolute

Mechanical tricuspid valve

Relative

Ventricular septal defect

Atrial septal defect

Left bundle branch block

Significant ventricular arrhythmias

Bioprosthetic tricuspid valve

Pneumonectomy

Ventricular pacing wire dependence

Tricuspid valve endocarditis

1. Sterile field. Following insertion of the introducer sheath, the sterile field should be maintained or reestablished. It is prudent for the operator to change sterile gloves and cover the operative field with a large sterile drape.

2. Preparing the PAC. After the PAC is opened, the balloon should be tested and three-way taps connected to the lumens. The operator passes off the female end of sterile pressure tubing to an assistant, who connects it to a transducer and continuous flushing system. All the lumens of the PAC are flushed, and the pressure in the distal (pulmonary artery) lumen is displayed on the monitor. Other lumens are occluded with the three-way taps. The protective plastic cover is drawn over the PAC.

3. Floating the PAC. With the curve of the catheter directed medially, the PAC is inserted 15 cm into the introducer sheath, and the plastic cover is pulled over the PAC and attached to the sheath. A central venous pressure waveform should be seen. The balloon is inflated and the PAC is slowly advanced while the operator observes the waveform on the monitor. First a right ventricular waveform (usually at 20 to 30 cm), then a pulmonary arterial waveform (usually at 35 to 50 cm) should be seen (Fig. 40-21). If a right ventricular waveform is not seen by 40 cm, the balloon should be deflated, the catheter withdrawn to 15 cm, and the process repeated. From the right ventricle, if a pulmonary arterial waveform is not seen by 60 cm, the catheter should be withdrawn until it is just in the right ventricle, and the process repeated. If there are difficulties advancing the catheter to the next chamber, twisting it 90 degrees or 180 degrees may be helpful. Once in the pulmonary artery, the catheter should be advanced a further 5 to 10 cm until a pulmonary arterial wedge pressure trace is seen. Deflating the balloon should restore the pulmonary arterial trace.

Figure 40.21 Pressure tracing seen during flotation of a pulmonary artery catheter. See text for details.

The catheter should be advanced only with the balloon inflated and withdrawn only with the balloon deflated. Unless advancing the catheter or measuring a wedge pressure, the balloon should be deflated. The pulmonary arterial trace must be continuously displayed so inadvertent wedging of the catheter tip can be rapidly identified—persistent or overwedging of the catheter tip can cause pulmonary arterial rupture. On a chest radiograph, the tip of the catheter should be just proximal to the edge of the pulmonary hilum. A more distal position may increase the risk for pulmonary arterial rupture.

Complications

In addition to complications of central venous catheterization, complications of PACs include arrhythmias, knotting or entrapment of the catheter, damage to the tricuspid or pulmonary valves, and pulmonary arterial rupture. Arrhythmias usually occur during manipulation of the catheter, particularly as it is advanced or withdrawn through the right ventricle. Arrhythmias are usually benign but ventricular tachycardia or fibrillation can occur. There is a small risk of causing right bundle branch block with catheter manipulations, which in a patient with left bundle branch block will result in complete heart block. Pulmonary arterial rupture is rare, occurring in 0.02% to 0.03% of insertions.^24,²⁵ Management of this condition is described in Chapter 26.

INSERTION OF AN INTRAAORTIC BALLOON PUMP CATHETER

The use of intraaortic balloon pumps (IABPs) is described in Chapter 22. Insertion is usually via a femoral artery using either a sheath (described here) or a sheathless technique. The advantage of an introducer sheath is that repositioning of the catheter is relatively easy; the disadvantage is that a larger caliber arterial puncture is required. Balloon catheters are sized according to the patient’s height and on the basis of the manufacturer’s recommendations. Relevant anatomy is discussed in the earlier material under the heading Femoral Vein Cannulation. Insertion of an IABP catheter involves the following steps.

1. Preparation of the patient. The patient is positioned as for femoral vein cannulation. Skin should be cleaned with 2% aqueous chlorhexidine and the operator should don a mask, sterile gloves, and a sterile gown. Large sterile drapes, covering both the patient and the bed, should be used to prevent contamination of the guide wire and catheter. A second clinician should be scrubbed in to assist the operator. In conscious patients, local anesthetic (lidocaine 5 to 10 ml with epinephrine 1:200,000) should be infiltrated over the insertion site.

2. Insertion of the introducer sheath. The needle should be inserted 2 to 3 cm below the inguinal ligament, directly over the femoral arterial pulsation, and angled at 45 to 60 degrees to the skin so that the artery is entered just distal to the inguinal ligament. Once the artery has been punctured, the guide wire is inserted through the needle for approximately 1 meter, and the needle is withdrawn. A small incision should be made at the insertion site. A fine dilator is advanced into the artery and withdrawn. The introducer sheath and dilator is then advanced into the artery. The dilator is removed and the guide wire is left in place. A unidirectional valve prevents back-bleeding through the sheath.

3. Preparation of the IABP catheter. An IABP catheter has two lumens: (1) a gas lumen for balloon inflation and deflation; and (2) a central lumen for pressure measurement. The catheter is measured against the patient to determine the approximate insertion distance; the distance from the insertion point to the suprasternal notch is a useful initial guide. The gas lumen should be aspirated to ensure that the balloon is fully deflated.

4. Insertion of the catheter. The catheter is loaded over the guide wire and advanced into the sheath. Once the catheter has been advanced an appropriate distance, the guide wire is removed, and the central lumen is allowed to back-bleed. This lumen is connected to a continuous flushing system and a pressure transducer, and the waveform is displayed on the IABP console. The gas lumen is connected to driveline tubing and then to the IABP console. Counterpulsation is commenced once an appropriate arterial waveform has been observed. If the waveform appears damped, the catheter should be withdrawn slightly and the central lumen flushed. Once a satisfactory position has been obtained, the protective plastic cover is drawn over the exposed catheter and attached to the introducer sheath. The catheter and sheath are sutured into position and a sterile dressing is applied.

The position of the guide wire and catheter within the aorta may be confirmed during insertion with either transesophageal echocardiography or fluoroscopy, aiming for a catheter tip position 2 cm distal to the origin of the left subclavian artery. A chest radiograph should be obtained at the completion of the procedure to confirm the correct position of the catheter tip, which is at the level of the inferior margin of the aortic arch. Distal pulses should be checked regularly.

Complications

The main complications of IABPs relate to arterial injury. Bleeding at the insertion site can cause localized or retroperitoneal hematoma and result in distal ischemia. A pseudoaneurysm or arteriovenous fistula can develop and require surgical correction. There is a potential for dislodgment of atheroma or dissection within the aorta and iliac arteries, which may compromise perfusion to the splanchnic organs and the lower limbs. The adequacy of lower limb perfusion should be checked and documented regularly. Rupture of the helium-filled balloon causes a gas embolism. If this occurs, the patient should be immediately placed in the head-down position to minimize the chance of cerebral embolization. Over several days, intraaortic balloon counterpulsation can lead to thrombocytopenia.

REMOVAL OF AN INTRAAORTIC BALLOON PUMP CATHETER

Prior to the removal of an IABP, the patient’s coagulation status and platelet count should be checked and significant abnormalities treated by blood component therapy (see Chapter 30). Eye protection, an apron, and sterile gloves should be worn to protect the operator against blood splashes. Securing sutures should be cut and the device placed in standby mode. The insertion site should be cleaned with 2% chlorhexidine. The balloon catheter should be disconnected from the driveline, but it is not necessary to evacuate the balloon manually with a syringe because the aortic pressure compresses it. The catheter is slowly withdrawn until the tail of the balloon engages the sheath, and firm pressure is applied over the artery distal to the insertion site. The catheter and sheath introducer are then slowly withdrawn together. Proximal bleeding from the insertion site should be allowed for 1 to 2 seconds to encourage extravascular loss of any thromboembolic material. Distal pressure is released and pressure is applied proximal to the insertion site to allow back-bleeding from the leg for 1 to 2 seconds. Then firm manual pressure over wadded sterile gauze should be applied to the wound just proximal to the skin insertion site (i.e., directly over the arterial puncture site) for at least 10 minutes. Further pressure is then applied for 20 to 30 minutes with either an inflated compression device (e.g., Femstop) or a 2.5- to 5-kg weighted sandbag. The patient should be kept flat for a further 2 hours. Regular checks of distal perfusion and the insertion site should be made during this time.

PERICARDIOCENTESIS

Pericardiocentesis is indicated for draining pericardial fluid collections that are causing hemodynamic compromise. It is not recommended for the draining of pericardial blood that has accumulated following cardiac surgery; surgical reexploration is indicated in that circumstance (see Chapter 20).

The standard approach to pericardiocentesis is the subxiphoid technique, which is described here. However, with the increased use of echocardiographic-guided drain placement, the apical approach has become popular. Whichever approach is used, echocardiographic guidance is recommended.

The patient should be supine with the head of the bed raised to 30 to 45 degrees. A full sterile technique should be employed as described earlier, including placing a sterile sheath over the echocardiography probe. Between 5 and 10 ml of lidocaine (1% with epinephrine 1:200,000) is infiltrated into the patient’s left subxiphoid region. The echocardiography transducer is placed in the apical position and a four-chamber view is obtained (see Fig. 7-4D). The needle should be inserted 0.5 cm to the left of the xiphoid process and 1 cm below the costal margin (Fig. 40-22). The needle should be angled at 45 degrees to the plane of the skin and directed toward the patient’s left shoulder. Once the tip of the needle has passed underneath the costal margin, the angle is reduced to 15 degrees. As the needle is advanced, continuous negative pressure should be applied to the syringe. The approximate distance from the skin to the pericardial sac varies with body habitus but is typically 6 to 8 cm. With echocardiography, the needle may be seen entering the pericardial sac. When fluid is aspirated, the syringe is removed and the guide wire inserted into the hub of the needle and advanced into the pericardium. The track is dilated and a pigtail catheter is advanced into the pericardium for a distance of 15 to 20 cm. The catheter should be sutured in place and connected to a fluid collection bag. A chest radiograph should then be obtained to confirm the position of the catheter and exclude a pneumothorax.

Figure 40.22 Technique of pericardiocentesis. See text for details.

Complications include ventricular perforation, arrhythmias, and pneumothorax. If ventricular perforation occurs, urgent surgical exploration is indicated.

DEFIBRILLATION AND CARDIOVERSION

The word “defibrillation” refers to the use of unsynchronized electric shocks; it is used to treat ventricular fibrillation and polymorphic ventricular tachycardia (see Chapter 20). The word “cardioversion” refers to the use of shocks timed to the R wave of the ECG; they are used to treat many organized arrhythmias (see Chapter 21). Delivery of an electric shock during ventricular repolarization (i.e., on the T wave of the ECG) can induce ventricular fibrillation. Thus, for organized rhythms, synchronized shocks must always be delivered.

Modern cardioverter/defibrillators deliver shocks that have biphasic waveforms, which increases the likelihood of success over older monophasic machines. Devices may be automatic or manual. Automatic devices analyze the patient’s rhythm and, if defibrillation is indicated, deliver an unsynchronized shock. They are suitable for use by the public, by paramedics, and in general hospital wards for treating ventricular fibrillation. They are unsuitable for use in intensive or coronary care units. Manual cardioverter/defibrillators can deliver both synchronized and unsynchronized shocks; the operator interprets the cardiac rhythm and determines the appropriate intervention. Appropriate energies for defibrillation and cardioversion are outlined in Chapters 20 and Chapter 21, respectively. The following steps are involved in delivering an electric shock:

1. Preparation. Conscious patients should be anesthetized prior to cardioversion. The cardioverter/defibrillator is turned on and, if available, self-adhesive pads are applied to the patient’s chest (Fig. 40-23).

2. Identification of the rhythm. The patient’s ECG is displayed on the cardioverter/defibrillator by one of three methods: (1) by the external pads (best in an emergency); (2) by slaving the ECG from the patient’s bedside monitor (best in an elective situation); (3) by connecting ECG leads from the cardioverter/defibrillator to the patient. If a synchronized shock is required, this mode should be activated. Synchronization is usually confirmed by the appearance of a dot on the R wave of the ECG. If dots appear above T waves, they are being incorrectly recognized as R waves, and the ECG leads should be adjusted until the R wave is correctly recognized.

3. Energy selection and charging. The energy level is selected. If self-adhesive pads have not already been applied, manual paddles are applied to the chest (over gel pads to improve conductance). The cardioverter/defibrillator is then charged. The operator should call out “charging,” and survey the bed space to ensure that no one is touching the patient.

4. Delivery of the shock. When the device has been charged, the operator should call out “stand clear,” followed by “shocking now,” just before delivering the shock. With synchronized cardioversion there may be a lag of 1 to 5 seconds before the shock is delivered. If paddles (as opposed to adhesive pads) are used, they should be kept firmly applied to the patient’s chest until the shock has been delivered.