Anaesthesia for Gynaecological and Genitourinary Surgery

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Anaesthesia for Gynaecological and Genitourinary Surgery

There are many techniques and considerations which are common to both urological and gynaecological anaesthetic practice. As in other areas of surgery, increasing numbers of older, and often more frail, patients require surgery. In both specialities, the need for pelvic or perineal surgical access requires positioning of the patient which is associated with specific complications. In both specialities, there is widespread adoption of endoscopic surgical techniques and there is increased emphasis on the need for anaesthetic techniques which allow for day-case surgery, or surgery involving fast-track recovery programmes.

GENERAL CONSIDERATIONS

Perineal, per urethra and per vaginal surgery mostly require the patient to be supine with the hips flexed and abducted and the knees bent. Lloyd Davies and lithotomy are the two common positions in which this is achieved. The main difference between them is the greater degree of flexion of the hips and knees in the lithotomy position. Because of the risk of nerve damage as a result of either direct compression or excessive stretching, care should be taken to avoid extreme hip flexion (femoral nerve compression, sciatic or obturator nerve stretching) and to avoid any prolonged pressure against the femoral and tibial condyles (common peroneal or saphenous nerve compression). When the patient is first put into either position, care should also be taken to avoid trapping the hands in the operating table mechanism. Calf compression leading to compartment syndrome has been associated with both positions and if the position needs to be adopted for many hours it is advisable to lower the legs intermittently to allow reperfusion to occur.

Hypotension from blood loss or regional anaesthesia may be masked by the legs being raised and may become apparent only after they are lowered at the end of surgery.

The Trendelenburg (head-down) position is often required during pelvic surgery and is associated with decreased functional residual capacity (FRC), increased risk of passive regurgitation and raised intracranial and intraocular pressures. Transperitoneal laparoscopic surgery (for example, laparoscopic prostate surgery or hysterectomy) may require steep Trendelenburg positioning (30–45°) for prolonged periods of time and careful attention to preoperative conditions such as glaucoma is necessary. There have been concerns that prolonged steep Trendelenburg position combined with the hypercapnia which often occurs during laparoscopy might cause a raised intracranial pressure (as much as a 150% rise in animal models) and anecdotal evidence suggests that patients are at risk of developing acute confusional states on emergence from anaesthesia. In order to reduce this risk, some anaesthetists have advocated the routine use of parenteral dexamethasone or mannitol intraoperatively. Studies measuring the degree of intraoperative cerebral oxygenation in urological patients positioned in this way suggest that it is well preserved.

Tracheal intubation is required in most patients who require prolonged head-down positioning in order to maintain adequate ventilation, and in patients who are at high risk of passive regurgitation it should be considered even for short procedures. If passive regurgitation occurs in the head-down position, gastric acid can pool around the eyes leading to corneal burns unless it is washed out rapidly, and the patient should be positioned such that the anaesthetist is able to see the face in case this occurs.

Renal surgery most often requires the patient to be in a lateral position with the table ‘broken’ in the middle in order to extend the flank. Cardiorespiratory stability is maintained in most patients despite one lung being dependent, although temporary hypotension sometimes occurs as a result of decreased venous return. Padding of the legs and arms is required to avoid peroneal, saphenous and ulnar nerve damage and care should be taken to avoid lateral neck flexion which may result in brachial plexus injuries. Corneal abrasions are surprisingly common in the lateral position, mostly as a result of inadvertent contact with apparatus near the head (for example HME filters).

Prone positioning is required only for percutaneous nephrolithotomy. For this procedure, patients require general anaesthesia with tracheal intubation and mechanical ventilation. In this position, it is essential that the tracheal tube is well secured. Careful attention should be paid to the position of the head, eye-padding, avoidance of abdominal compression and pressure-point protection (nose, chin, genitals, knees).

Laparoscopic Procedures

As in other areas of surgery, there has been an increase in the number of urological and gynaecological procedures which are performed laparoscopically, including surgery for hysterectomy, oophorectomy, cystectomy, nephrectomy and prostatectomy. Laparoscopic surgery is associated with lower intraoperative blood loss, lower postoperative analgesia requirements and faster postoperative recovery times. There is also less potential for heat loss than during open surgery.

Most laparoscopic surgery involves a transperitoneal approach and requires a pneumoperitoneum. The exceptions to this include renal surgery, in which a retroperitoneal approach is also possible, and radical prostate surgery, in which anteroperitoneal gas insufflation may be used. It has been suggested that anteroperitoneal and retroperitoneal approaches allow for faster postoperative recovery.

The pneumoperitoneum required for laparoscopic surgery is accomplished by the insufflation of carbon dioxide to a pressure of 10–15 mmHg. This can be performed after the insertion of a laparoscopic port or a Veress insufflation needle. In both cases, there is the potential for inadvertent damage to major blood vessels, or for subcutaneous insufflation resulting in surgical emphysema. Very rarely, venous gas embolism occurs as a result of insufflation directly into a blood vessel.

The cardiovascular effects of peritoneal insufflation include increases in venous return and cardiac output, accompanied by an increase in systemic vascular resistance. If higher pressures are required, compression of the vena cava may occur, resulting in a decrease in venous filling. Occasionally, the peritoneal stimulation which occurs during gas insufflation can cause a vagal bradycardic response requiring rapid deflation and the administration of an anticholinergic.

Pneumoperitoneum also results in decreased functional residual capacity, and when combined with the Trendelenburg position, there is an increased risk of atelectasis and V/Q mismatch. Tracheal intubation and mechanical ventilation can help to minimize the effects, particularly if positive end-expiratory pressure is applied, but in patients with marked respiratory disease, a prolonged pneumoperitoneum may not be tolerated well. On rare occasions, a congenital diaphragmatic fistula or a surgical breach of the diaphragm may result in a pneumothorax or pneumomediastinum which can interfere with ventilation.

Carbon dioxide is absorbed through the peritoneum during laparoscopic surgery, resulting in a raised PaCO₂, tachycardia and increased myocardial contractility. Retroperitoneal insufflation often results in a greater degree of gas absorption which may persist after surgery. Anteroperitoneal radical prostate surgery is worth a special mention because it can result in severe surgical emphysema in the scrotal area and/or chest and face. The surgical emphysema is caused by carbon dioxide spreading throughout the subcutaneous tissues where it is readily absorbed, resulting sometimes in severe hypercapnia. Methods to decrease the degree of surgical emphysema and hypercapnia include ensuring adequate muscle relaxation (for example by using an infusion of muscle relaxant) and by increasing the minute volume achieved by mechanical ventilation both intraoperatively and sometimes for a short period after surgery has ended. The use of nitrous oxide is not recommended during anteroperitoneal surgery because it exacerbates the degree of surgical emphysema.

The frequency with which laparoscopic procedures are converted to open operation depends on the operation and the experience of the operator. It may be appropriate to ask the surgeon beforehand whether conversion to an open procedure is likely.

Other Endoscopic Surgery

Urethral or transcervical endoscopic approaches can be used to perform bladder, prostate, ureteric and intrauterine surgery. Flexible endoscopes may be used for some procedures, such as surveillance cystoscopy, in which case topical anaesthesia may be sufficient. If surgical resection is necessary, it is probable that a rigid endoscope will be required, facilitated by general or spinal anaesthesia. The rigid endoscope allows the use of rigid instruments, such as a resection diathermy loop, and fluid irrigation which allows visualization of the surgical field and washes away blood and resected tissue.

The choice of irrigation fluid is determined by the surgical technique. If monopolar diathermy equipment is used, a relatively non-conducting irrigating fluid is required so that current is not dissipated away from the point at which the diathermy equipment comes into contact with the body. In contrast, bipolar equipment works better with an irrigating fluid which conducts charge from the active part of the instrument to the nearby return electrode. Until recently, most diathermy equipment used by urologists was monopolar and the irrigation fluid of choice was glycine, which combined good optical properties with poor electrical conduction. Saline irrigation is used with the more recently developed bipolar resectoscopes.

Endoscopic resection with continuous irrigation requires the fluid to be under pressure, achieved usually by hanging the fluid reservoir from a drip-stand. Fluid can be forced under pressure into tissue planes as well as veins or sinuses opened by the diathermy process. In this manner, a large amount of fluid can be absorbed, which can result in fluid overload in susceptible patients. If the irrigating fluid is glycine, TUR (transurethral resection) syndrome may also develop (see below).

Lasers can also be used for transurethral resection and are used commonly for prostatic resection. There are various techniques available using different lasers, including holmium and Greenlight lasers. Smaller instrumentation of the urethra may be possible, including the use of flexible endoscopes, and there is minimal blood loss with faster postoperative recovery times.

TRANSURETHRAL RESECTION (TUR) SYNDROME

Despite the name, TUR syndrome is not exclusive to transurethral surgery. It is sometimes known as TURP (trans-urethral resection of the prostate) syndrome, and, as the name implies, it is most commonly associated with endoscopic prostatic surgery in which prostatic sinuses and veins are cut during resection, allowing irrigating fluid to be absorbed. Less commonly, TUR syndrome has been reported after other procedures, including bladder tumour resection, cystoscopy, various forms of lithotripsy and transcervical endometrial resection.

TUR syndrome occurs if a large volume of hypotonic irrigating solution is absorbed rapidly, resulting in rapid changes in serum osmolality and electrolyte concentrations. Glycine solution is the most commonly used hypotonic irrigating fluid in the UK, and commercial solutions have an osmolality of approximately 200 mosmol L^− 1. In high concentrations, glycine can exhibit toxic effects on the cardiovascular and central nervous systems (including retinal neurotransmission) in addition to the effects of altered blood chemistry. The clinical findings associated with TUR syndrome are shown in Table 27.1.

TABLE 27.1

Clinical Features of TUR Syndrome

Symptoms in the Awake Patient	Clinical Signs and Investigation Results
Vertigo	Confusion or agitation
Nausea and/or vomiting	Decreased consciousness
Abdominal pain	Seizures
Visual disturbance/blurred vision Dyspnoea Chest tightness	Pupillary dilatation Papilloedema Bradypnoea/hypopnoea Pulmonary oedema Cyanosis Oliguria Hypotension (although there may be initial hypertension) Bradycardia or other dysrhythmias Widened QRS and/or ST changes on ECG Cardiac arrest Hyponatraemia Decreased serum osmolality Hyperammonaemia

TUR syndrome usually occurs only after more than 2 L of irrigating fluid have been absorbed into the circulation, but because this may occur as a result of fluid redistribution from perivesicular tissue planes into the vasculature, the onset of TUR syndrome may be delayed until some hours after surgery. In addition to the potential effects of fluid overload, the clinical features of TUR syndrome are those of decreased or altered consciousness and cardiovascular compromise. The most obvious biochemical abnormality is acute hyponatraemia. Acute haemolysis has also been associated with TUR syndrome, but is unlikely to occur with modern glycine solutions.

TUR syndrome is more likely to occur when higher irrigation pressures are used or if surgical resection is prolonged or extensive (e.g. if the prostate is very large or if perforation of the prostatic capsule occurs during surgery). Various attempts have been made to monitor the degree of fluid absorption, including adding ethanol to the irrigation fluid (in order to monitor exhaled ethanol concentrations), strict fluid input/output measurement, and semi-continuous weighing of the patient. None of these techniques has gained widespread acceptance because of the inherent difficulties associated with their use.

The risk of TUR syndrome can be minimized by limiting the duration of surgery, decreasing the irrigation pressure (by limiting the height of the reservoir above the patient to 60–80 cm above the operating field), ensuring that glycine irrigation is converted to saline as soon as surgery is complete and the judicious use of diuretics if surgery is prolonged. The use of bipolar resection with saline irrigation exposes the patient to the risk of fluid overload alone, rather than to the biochemical derangement of TUR syndrome.

The use of spinal anaesthesia is thought to make earlier identification of TUR syndrome possible because the initial signs are most commonly agitation and restlessness.

If TUR syndrome is suspected, the operation should be concluded as rapidly as possible. The treatment of TUR syndrome consists of supportive measures combined with diuretics such as furosemide or mannitol. Hypertonic saline (i.e. 3% solution) may be required in patients who develop extreme neurological or myocardial dysfunction. Sodium replacement must be performed in a controlled manner in order to avoid pontine demyelination; an increase in serum sodium concentration of 1–2 mmol L^− 1 h^− 1 is widely accepted to be within safe limits (to a maximum of 12 mmol L^− 1 within a 24-h period). Fortunately, the sodium changes which occur in TUR syndrome are so acute that this complication of treatment is unlikely to occur. A commonly quoted formula to guide sodium replacement is [body weight × 1.2] mL h^− 1 of 3% saline, which increases the serum sodium concentration by about 1 mmol L^− 1 h^− 1. High-dependency monitoring is required.

REGIONAL ANAESTHESIA

Regional anaesthesia, either alone or in combination with general anaesthesia, is often the preferred technique for many gynaecological and genitourinary procedures. It provides excellent intraoperative and postoperative analgesia and is perceived as being associated with decreased risks of respiratory and airway dysfunction in patients with significant comorbidities. Epidural anaesthesia is often combined with general anaesthesia in procedures in which there is likely to be prolonged abdominal pain postoperatively, or if it is anticipated that there may be significant disturbance to bowel or other intraperitoneal organs; examples include open surgery for cystectomy, Wertheim’s hysterectomy or nephrectomy. Spinal anaesthesia may be combined with general anaesthesia for procedures in which postoperative pain is likely to be severe, but not as prolonged, e.g. operations involving Pfannenstiel or lower midline abdominal incisions, such as hysterectomy or open prostate surgery. The addition of an intrathecal opioid to spinal anaesthesia can extend the duration of spinal analgesia further into the postoperative period, but careful monitoring is required to avoid complications as there is an increased risk of delayed respiratory depression (particularly if a parenteral opioid is also prescribed) and increased incidences of nausea, vomiting and pruritus. If spinal anaesthesia is used in combination, it should be performed before induction of general anaesthesia in order to minimize the risk of inadvertent nerve or spinal cord damage. Sympathetic nerve blockade occurs in association with spinal or epidural anaesthesia, and profound hypotension can result when this is combined with the cardiovascular effects of general anaesthetic agents. This is particularly true of ‘one-shot’ techniques such as spinal anaesthesia performed immediately before induction of general anaesthesia.

Spinal anaesthesia without general anaesthesia is often the preferred anaesthetic technique for TURP and cystoscopic procedures. Not only is it perceived as being safer in patients with significant respiratory or airway comorbidities but it also offers the potential for early identification of TUR syndrome when monopolar resection techniques are used. For procedures which require bladder irrigation, anaesthesia with a sensory block of up to up to at least the T10–12 dermatomes is needed to prevent discomfort caused by distension of the bladder. Occasionally, spinal anaesthesia results in penile tumescence, which makes penile surgery and instrumentation of the urethra difficult. Intravenous ketamine has been used to treat this complication but its efficacy is probably limited and side-effects may occur. Intracorporeal administration of a low-dose α-adrenergic agonist (e.g. phenylephrine 100–200 μg) is likely to be more effective, with little risk of systemic side-effects.

More localized regional or infiltrative techniques may provide adjunctive analgesia for other gynaecological or genitourinary procedures. Local anaesthetic infiltration is often used during perineal surgery, and the addition of a vasoconstrictor may reduce local bleeding. Anaesthetists should be aware that a vasoconstrictor used by the surgeon has the potential to cause systemic effects as it is absorbed.

Other techniques include the use of caudal block to provide saddle analgesia, and transversus abdominis plane (TAP) blocks to provide analgesia of the abdominal wall. A penile ring block provides excellent analgesia for penile operations such as circumcision, but must be performed using a plain local anaesthetic solution to avoid vasoconstriction.

PERIOPERATIVE INFECTIONS

There is a high incidence of occult urinary tract infections in patients with urinary tract stones or an indwelling catheter. Antimicrobial prophylaxis can be used to help to prevent bacteraemia, particularly during surgery in which the urinary tract mucosa is likely to be breached (e.g. stone extraction, bladder tumour or prostate resection). Antimicrobial prophylaxis may also be required in surgery in which there is a risk of bowel perforation, e.g. cystectomy or radical prostate surgery.

OTHER CONSIDERATIONS

Postoperative nausea and vomiting occur more commonly after gynaecological surgery and the pre-emptive use of antiemetics is often advisable in these patients.

Venous thromboembolic events are strongly associated with pelvic and renal cancers and surgery. Appropriate prophylaxis should always be considered, but special attention should be paid to the possibility that venous thrombosis may already be present before surgery, necessitating preoperative anticoagulation and possibly the insertion of a filter in the inferior vena cava (IVC).

Blood conservation strategies should be considered before operations associated with major blood loss. This may include the routine use of anti-fibrinolytic medications such as tranexamic acid. Cell salvage technology may also be of benefit, but its use may be limited in cancer surgery because of the theoretical risk of haematogenous metastasis. Currently, many centres infuse cell-salvaged blood through white cell filters for cystectomy and radical prostate operations, but not for gynaecological malignancies. Cell salvage should be stopped immediately before planned bowel incision, for example at the time of ileal conduit formation.

A urinary catheter is often required in the postoperative period, particularly if ongoing bladder irrigation is required. Care should be taken when moving the patient to avoid undue tension and accidental displacement, particularly after a urethral anastomosis has been created. Bladder spasm is a common problem in the postoperative period, often occurring in previously catheter-naïve patients who may benefit from the addition of a muscarinic receptor antagonist such as hyoscine butylbromide.

Active warming measures are necessary during many gynaecological and urological surgical procedures, particularly during open procedures or those which require continuous fluid irrigation.

ANAESTHETIC IMPLICATIONS OF SPECIFIC SURGICAL TECHNIQUES

Surgery for cystectomy, hysterectomy and oophorectomy is performed with the patient head-down and either supine or in the lithotomy/Lloyd Davies position. For open abdominal and laparoscopic approaches, tracheal intubation and mechanical ventilation are required. For open approaches, combined general and regional anaesthesia provide good intraoperative and postoperative analgesia. The choice of technique depends on the incision used, with Pfannenstiel incisions being more amenable to spinal anaesthesia. Alternatively, postoperative patient-controlled analgesia (PCA) regimens can be used, and there is increasing use of postoperative local anaesthetic wound infusion catheters. Laparoscopic approaches are likely to require less analgesia postoperatively, but this depends on any final incision required to remove the resected viscera.

Cystectomy and large gynaecological resections are often prolonged surgical procedures with the potential for marked physiological derangements to occur intraoperatively which are likely to necessitate the use of invasive arterial and/or central venous monitoring. Surgery for gynaecological pelvic cancers can sometimes be very extensive, requiring the excision of multiple structures at once, e.g. pelvic exenteration surgery. There is the potential for very large blood loss. In such cases, high-dependency monitoring is likely to be needed in the postoperative period.

Chronic blood loss relating to the disease process requiring cystectomy or hysterectomy may mean that the patient is anaemic before surgery. Other preoperative considerations include the potential for large pelvic cancers to affect renal function as a result of either chemotherapy or ureteric obstruction/compression. Preoperative chemotherapy, especially for ovarian cancer, can also result in systemic complications such as cardiac impairment. The physical effects of large pelvic tumours can include abdominal mass effects such as abdominal compartment syndrome, obstruction of the IVC and diaphragmatic splinting. The extent of any preoperative nerve compression should be documented before regional anaesthesia is performed.

Cystectomy requires the formation of an ileal conduit into which the ureters are diverted. Generally, this does not impact on renal function, and potentially nephrotoxic drugs such as NSAIDs can be used once there is minimal risk of postoperative hypotension. One of the commonest complications of ileal conduit formation is postoperative ileus, which can present many days after surgery. Epidural analgesia has been suggested as a means of promoting earlier recovery of gut function (probably by reducing postoperative use of opioids), as has the avoidance of insertion of a nasogastric tube during surgery.

Vaginal hysterectomy causes less surgical trauma than open abdominal surgery and is less painful postoperatively. Depending upon the patient, a general anaesthetic with a laryngeal mask airway, or spinal anaesthesia alone, may be sufficient. There is the potential for perioperative occult bleeding to occur because of the impaired surgical view.

Laparoscopic sterilization requires general anaesthesia but is normally relatively short and can often be performed using a laryngeal mask airway. The degree of postoperative pain as a result of placing clips around the fallopian tubes is often hard to predict, although most patients require only oral analgesics.

Emergency surgery for ectopic pregnancy may be either semi-urgent surgery as a result of early detection, or, if rupture and haemorrhage have occurred, a true emergency requiring immediate resuscitation and surgery. Patients are usually young and fit and the signs of haemorrhage are often masked, but if bleeding is suspected there should be minimal delays in proceeding to open surgery; if possible, two large-bore venous cannulae should be inserted and intravenous fluid resuscitation started as soon as possible. A rapid-sequence induction (RSI) technique should be employed because of the risk of a full stomach. If the patient is grossly hypovolaemic, hypotension may occur on induction and this may require fluids and/or vasopressors. Blood should be cross-matched and transfused as required, and any coagulopathy corrected aggressively.

If there is no evidence of haemorrhage, a laparoscopic technique may be used; tracheal intubation and artificial ventilation are required and RSI may be indicated. Both procedures are likely to be painful post-operatively requiring both simple analgesics and opiates, such as a patient-controlled opiate analgesia infusion.

Nephrectomy and Renal Surgery

The indications for nephrectomy include the presence of a renal tumour, intractable infection, trauma, calculous disease, renovascular hypertension or as a living donor. Renal tumours are associated with a high incidence of preoperative renal tract blood loss and the patient may be anaemic before surgery. Paraneoplastic syndromes are also common in patients with a renal tumour and may cause hypercalcaemia, hypertension, polyneuropathy and fever. As in other surgery for malignant disease, anaesthetic assessment should take into account the possibility of metastatic spread, particularly to the lungs. The extent of local spread is also important because tumours which impinge on the inferior vena cava may require it to be clamped during surgery.

If a tumour is very large or vascular, endovascular embolization under radiological guidance may be performed a day or so before surgery. Preoperative analgesia is required, and an epidural block is often inserted before the embolization.

The removal of a kidney does not necessarily impact on postoperative renal function, particularly if the kidney was functioning poorly beforehand, but indices of renal function should be reviewed by the anaesthetist. Potentially nephrotoxic drugs such as NSAIDs and aminoglycosides can often be used provided that renal function is adequate and perioperative hypotension avoided.

Clearly, in patients whose final functioning kidney is being removed, dialysis will be required postoperatively and care should be taken to avoid large doses of drugs which are likely to accumulate, such as morphine. Care should also be taken if possible to avoid placing venous cannulae in areas such as the forearm because these are likely to be needed for future fistula formation. A partial nephrectomy may be considered as a means of preserving some renal function, but these have a lower rate of tumour clearance and a higher incidence of intraoperative or postoperative haemorrhage.

The anaesthetic requirements for pyeloplasty are very similar to those for nephrectomy except that the patient may be positioned in the lithotomy position first, whilst a ureteric stent is inserted.

Renal surgery may be performed using open or laparoscopic surgery and the choice of surgical technique is often dependent on the size of the tumour or the complexity of the resection. In both eventualities, tracheal intubation and artificial ventilation are necessary to allow surgical access and to minimize complications. If open surgery is performed, epidural analgesia usually provides good postoperative pain relief, although patient-controlled analgesia regimens with morphine are also appropriate. Intercostal or intrapleural nerve blocks can be used but are relatively short-acting and risk the development of a pneumothorax. After laparoscopic procedures, a parenteral opioid should generally be sufficient to provide analgesia.

Occasionally, a pneumothorax develops if the pleura is breached during renal surgery. Pneumothoraces are generally self-limiting and resolve after laparoscopic insufflation is discontinued, or are maintained at a small size by the use of positive pressure ventilation during open surgery. It is rare to need to insert an intrapleural drain.

In patients whose cardiovascular system is unstable, or if major blood loss is expected, invasive arterial and/or central venous monitoring should be employed.

Prostate Surgery

Prostatic surgery may be required either for cancer or for benign prostatic hypertrophy. In both cases, the incidence of disease increases with age and patients may be frail or affected by comorbidities. In addition, many patients with benign prostatic hypertrophy present after an episode of acute urinary retention which has been triggered by another medical insult such as recent major surgery. The most prevalent group for acute urinary retention is men aged 75–84 years, in whom the one-year mortality after presentation is approximately 13% if the retention occurred spontaneously and 18% if the episode of retention was precipitated by an acute event. These figures are more than doubled if comorbidities are also present.

Preoperative assessment should aim to identify significant comorbidities, especially those affecting the cardiovascular or respiratory systems. In addition to the risks inherent in anaesthetizing patients with cardiovascular disease, the significant fluid shifts involved in transurethral resection of the prostate (TURP) may result in fluid overload in susceptible individuals. Any pre-existing metabolic derangement, such as hyponatraemia resulting from diuretic use or other causes, is likely to be exacerbated. Prostatic disease may also affect renal function and this should be assessed preoperatively.

Complications associated with TURP include blood loss, which can often be difficult to quantify because of the use of irrigation fluid. Other complications include hypothermia, sepsis and TUR syndrome. Although general anaesthesia using a laryngeal mask airway can be used, spinal anaesthesia is often the preferred anaesthetic technique for TURP because of the decreased risks of respiratory and airway dysfunction. Spinal anaesthesia may also provide the potential for early identification of TUR syndrome when monopolar techniques are used because confusion and agitation are amongst the earliest clinical signs (see Table 27.1).

If the prostate is very large, a retropubic prostatectomy (Millen’s procedure) may be required. This approach uses a Pfannenstiel-type incision, and because of the size of the prostate, there is an increased risk of major blood loss during the procedure.

Curative prostatic cancer surgery (radical prostatectomy) requires transperitoneal or anteroperitoneal resection which can be performed using open or laparoscopic techniques. Both require general anaesthesia and tracheal intubation, with or without spinal or epidural analgesia. During laparoscopic radical prostatectomy, the urethra is resected at the base of the bladder during the procedure and it must be borne in mind that a large diuresis during this time may obscure the surgical field. There is the potential for major haemorrhage using either approach.

Newer transrectal ultrasound treatments (high-intensity focussed ultrasound, HIFU) have been developed and are used in some centres. These procedures cause minimal physiological disturbance with much less postoperative pain. Anaesthesia for these simply requires the patient to lie still in the lateral position for 1–2 h.

Intrauterine and Transurethral Bladder Surgery

Suction termination of pregnancy (STOP) requires dilatation of the cervix and instrumentation of the uterus under general anaesthesia. A volatile anaesthetic agent can be used to maintain anaesthesia but may result in uterine relaxation and is therefore avoided by many anaesthetists. The procedure is often very short and intermittent propofol can be used, accompanied by a short-acting opioid analgesic. Deep anaesthesia is necessary at the time of cervical dilatation because this can be very stimulating and may result in a profound vagal response or laryngospasm.

Evacuation of retained products of conception (ERPC) has similar anaesthetic requirements and both procedures are associated with the risk of haemorrhage and uterine perforation requiring further surgery.

Oxytocin is often administered at the end of these procedures to promote uterine contraction and decrease postoperative bleeding. The administration of oxytocin may result in transient hypotension and tachycardia. Simple oral analgesics are usually sufficient to control postoperative pain.

Donor egg retrieval (as part of fertility treatment) is performed using transvaginal aspiration under ultrasound guidance. It can be performed under sedation or using a general anaesthetic with a laryngeal mask airway. Complications during egg retrieval (e.g. haemorrhage or damage to intervening structures) are rare.

Cervical and transcervical surgery includes resection of tumours, endometrial ablation for menorrhagia (performed using thermal or electrocautery), hysteroscopy and cervical dilatation and uterine curettage. General and regional anaesthetic techniques are both suitable.

Brachytherapy may be used to insert radioactive sources directly into cancerous areas such as the prostate, uterus or cervix. Anaesthesia is usually required for gynaecological brachytherapy. Prolonged postoperative analgesia may be needed, for example if a vaginal pack is inserted, and spinal, epidural or caudal techniques can be used. Institutions undertaking brachytherapy have specific protocols designed to protect staff from ionizing radiation.

Patients with a bladder tumour are often elderly and may have a history of cigarette smoking (the same is also true for cervical and vulval cancer); cardiorespiratory comorbidities should be identified preoperatively.

Bladder tumours often require many years of regular surveillance and intermittent resection. Anaesthesia for cystoscopy has to facilitate bladder irrigation but not always bladder tumour resection; it is often difficult to predict the extent of surgery preoperatively. General anaesthesia with a laryngeal mask airway is generally sufficient as these procedures are often short.

Spinal anaesthesia is a good alternative for higher risk patients, although patients with respiratory disease may be more prone to coughing when lying supine with legs raised in the lithotomy position, and coughing can make surgery difficult and potentially hazardous. Resection of tumours from the lateral bladder wall may result in obturator nerve stimulation, which can also be hazardous as a result of sudden leg movements. In some patients, there may be a surgical request for administration of a neuromuscular blocking drug in order to avoid this complication.

Complications of transurethral resection of bladder tumours (TURBT) include TUR syndrome, haemorrhage and bladder perforation. Bladder perforation may not be immediately obvious in the postoperative period, especially while the continuing effects of spinal anaesthesia mask pain. Blood clots may cause postoperative obstruction of the bladder catheter and urinary retention, even if an irrigating catheter is used.

Postoperative pain associated with TURBT and transcervical surgery is often relatively easy to control with simple analgesics, accompanied by intermittent administration of an opioid if required.

Perineal, Penile and Testicular Surgery

Testicular surgery, e.g. repair of hydrocoele or investigation of a suspected testicular torsion, involves a scrotal incision, and general or spinal anaesthesia can be used. Supplemental infiltration of local anaesthetic may provide additional analgesia. Orchidectomy is often performed using an inguinal incision, and local infiltration or an ilioinguinal nerve block may be of benefit. If orchidectomy is performed for testicular cancer, the possibility of distant metastases should be considered. Para-aortic node dissection may also be required, which carries with it all the implications of major abdominal surgery.

General and spinal anaesthesia are both appropriate for most penile or perineal procedures. An additional penile ring block can provide good analgesia, and may be used as the sole anaesthetic for circumcision. Vulval operations may benefit from local anaesthetic infiltration. Antibiotic prophylaxis is not routinely required, but is indicated if a penile implant is inserted or for repair of penile fracture. Radical vulvectomy and penile amputation are both used for the resection of cancers and are likely to include lymph node dissection. Both have the potential for more severe blood loss.

Fournier’s gangrene (fasciitis of the perineum) requires extensive debridement of the scrotum and perineum. Postoperative pain may be quite severe and significant blood loss may occur. Patients with this condition are septic and postoperative HDU care is recommended. Broad-spectrum antimicrobial treatment should be started before surgery.

Continence Surgery

Various procedures can be performed to promote continence. Pelvic floor repair and transvaginal tape (TVT, in which a tape is inserted transvaginally around the bladder neck with both ends coming out on to the abdominal skin) can both be performed under general or spinal anaesthesia, and supplemental local anaesthetic infiltration may be used. Postoperative analgesia requirements are generally low.

Abdominal procedures such as colposuspension can be performed using open or laparoscopic approaches and are associated with slightly more postoperative pain. Although spinal anaesthesia can be sufficient for open procedures using a Pfannenstiel incision, it is more usual to use general anaesthesia with tracheal intubation and mechanical ventilation. If surgery involves the insertion of a bladder-neck prosthesis, prophylactic antibiotics are required.

Surgical techniques to increase the bladder capacity include Helmstein’s procedure and Clam cystoplasty. Helmstein’s procedure is performed rarely and consists of forced bladder distension using fluid which can then be kept in place using a clamped catheter for 4–6 h. This results in prolonged discomfort and epidural anaesthesia is usually employed until the catheter is released. Clam cystoplasty requires the bladder to be incised and a ‘patch’ of small bowel to be sutured to the edges of the incision in order to increase bladder volume. The anaesthetic requirements are very similar to those for cystectomy.

Surgery for Renal Tract Stones

Stones within the bladder or ureter can often be removed using cystoscopy with or without ureteroscopy. Mechanical or laser instruments may be used for removal of the stones; if a laser is used during surgery, the general precautions for their use should be followed. Ureteric stents (JJ stents) may be inserted around the time of surgery, and on-table X-ray imaging is often needed. General or regional anaesthesia may be used; although urethral stimulation during the procedure occasionally necessitates supplemental analgesia if spinal anaesthesia is employed.

Occasionally, bladder stones are too large for this approach and a mini-Pfannenstiel incision is required. This has similar anaesthetic requirements to a retropubic prostatectomy.

Percutaneous nephrolithotomy/lithotripsy (PCNL) is performed when extracorporeal shockwave lithotripsy has failed. The procedure is performed in two stages, the first stage being cystoscopy and insertion of a ureteric balloon. During the second stage, the patient is placed in the prone position, a percutaneous tract is formed down to the renal pelvis under X-ray guidance and a nephroscope is inserted. Ultrasonic fragmentation or nephroscopic forceps are used to break up the stone. Irrigation with saline is used to flush out fragments of stone. Fluid can be forced into the retroperitoneal or peritoneal spaces, and this can occasionally be very severe, resulting in a ‘tense abdomen’ with diaphragmatic splinting. Haemorrhage from the kidney or nearby organs is also possible, and it is sometimes difficult to differentiate between irrigation fluid effects and retroperitoneal haematoma or haemoperitoneum. Pneumothoraces can also occur.

All surgery for renal tract stone removal carries the risk of postoperative bacteraemia and sepsis, and, as with other procedures which require irrigation, there is the potential for significant cooling to occur.

Tracheal intubation and mechanical ventilation are necessary for PCNL surgery because of the need for prone positioning.

FURTHER READING

Armitage, J.N., Sibanda, N., Cathcart, P.J., et al. Mortality in men admitted to hospital with acute urinary retention: database analysis. Br. Med. J. 2007;335:1199–1202.

Conacher, I.D., Soomro, N.A., Rix, D. Anaesthesia for laparoscopic urological surgery. Br. J. Anaesth. 2004;93:859–864.

Cousins, J., Howard, J., Borra, P. Principles of anaesthesia in urological surgery. Br. J. Urol. 2005;96:223–229.

Knight, D.J.W., Mahajan, R.P. Patient positioning in anaesthesia. Continuing Education in Anaesthesia, Critical Care and Pain. 2004;4:160–163.

Midgley, S., Tolley, D.A. Anaesthesia for laparoscopic surgery in urology. European Association of Urology Update Series. 2006;4:241–245.

Moore, J., McLeod, A. Anaesthesia for gynaecological oncology surgery. Current Anaesthesia & Critical Care. 2009;20:8–12.

O’Donnell, A.M., Foo, I.T.H. Anaesthesia for transurethral resection of the prostate. Continuing Education in Anaesthesia, Critical Care and Pain. 2009;9:92–96.

Park, E.Y., Koo, B.N., Min, K.T., Nam, S.H. The effect of pneumoperitoneum in the steep Trendelenburg position on cerebral oxygenation. Acta Anaesthesiol. Scand. 2009;53:895–899.

Vijayan, S. TURP syndrome. Trends in Anaesthesia and Critical Care. 2011;1:46–50.

Related

Smith and Aitkenheads Textbook of Anaesthesia 6E