Chapter 32: Anesthesia for Genitourinary Surgery

KEY CONCEPTS

• Next to the supine position, the lithotomy position is the most commonly used position for patients undergoing urological and gynecological procedures. Failure to properly position and pad the patient can result in pressure sores, nerve injuries, or compartment syndromes.

• The lithotomy position is associated with major physiological alterations. Functional residual capacity decreases, predisposing patients to atelectasis and hypoxia. Elevation of the legs drains blood into the central circulation acutely. Mean blood pressure often increases, but cardiac output does not change significantly. Conversely, rapid lowering of the legs from the lithotomy or Trendelenburg position acutely decreases venous return and can result in hypotension. Blood pressure measurement should be taken immediately after the legs are lowered.

• Because of the short duration (15–20 min) and outpatient setting of most cystoscopies, general anesthesia is often chosen, commonly employing a laryngeal mask airway.

• Both epidural and spinal blockade with a T10 sensory level provide excellent anesthesia for cystoscopy.

• Manifestations of TURP (transurethral resection of the prostate) syndrome are primarily those of circulatory fluid overload, water intoxication, and, occasionally, toxicity from the solute in the irrigating fluid.

• Absorption of TURP irrigation fluid is dependent on the duration of the resection and the pressure of the irrigation fluid.

• When compared with general anesthesia, regional anesthesia for TURP may reduce the incidence of postoperative venous thrombosis. It is also less likely to mask symptoms and signs of TURP syndrome or bladder perforation.

• Patients with a history of cardiac arrhythmias and those with a pacemaker or implantable cardioverter defibrillator (ICD) may be at risk for developing arrhythmias induced by shock waves during extracorporeal shock wave lithotripsy (ESWL). Shock waves can damage the internal components of pacemaker and ICD devices.

• Patients who are undergoing retroperitoneal lymph node dissection and who have received bleomycin preoperatively are at increased risk for developing postoperative pulmonary insufficiency. These patients may be particularly at risk for oxygen toxicity and fluid overload, and for developing acute respiratory distress syndrome postoperatively.

• For patients undergoing kidney transplantation, the preoperative serum potassium concentration should be below 5.5 mEq/L and existing coagulopathies should be corrected. Hyperkalemia has been reported after release of the vascular clamp following completion of the arterial anastomosis, particularly in pediatric and other small patients. Release of potassium contained in the preservative solution has been implicated as the cause of this phenomenon.