Anesthesia for Cystoscopy

CYSTOSCOPY

Preoperative Considerations

Cystoscopy is the most commonly performed uro-logical procedure, and indications for this investi-gative or therapeutic operation include hematuria, recurrent urinary infections, renal calculi, and urinary obstruction. Bladder biopsies, retrograde pyelograms, transurethral resection of bladder tumors, extraction or laser lithotripsy of renal stones, and placement or manipulation of ureteral catheters (stents) are also commonly performed through the cystoscope.

Anesthetic management varies with the age and gender of the patient and the purpose of the procedure. General anesthesia is usually necessary for children. Viscous lidocaine topical anesthesia with or without sedation is satisfactory for diag-nostic studies in most women because of the short urethra. Operative cystoscopies involving biopsies, cauterization, or manipulation of ureteral catheters require regional or general anesthesia. Many men prefer regional or general anesthesia even for diag-nostic cystoscopy.

Intraoperative Considerations

A. Lithotomy Position

Next to the supine position, the lithotomy position is the most commonly used positionfor patients undergoing urological and gynecologi-cal procedures. Failure to properly position and pad the patient can result in pressure sores, nerve inju-ries, or compartment syndromes. Two people are needed to safely move the patient’s legs simultane-ously up into, or down from, the lithotomy position. Straps around the ankles or special holders support the legs in lithotomy position ( Figure 31–1). The leg supports should be padded wherever there is leg or foot contact, and straps must not impede circula-tion. When the patient’s arms are tucked to the side, caution must be exercised to prevent the fingers from being caught between the mid and lower sec-tions of the operating room table when the lower section is lowered and raised—many clinicians com-pletely encase the patient’s hands and fingers with

protective padding to minimize this risk. Injury to the tibial (common peroneal) nerve, resulting in loss of dorsiflexion of the foot, may result if the lateral knee rests against the strap support. If the legs are allowed to rest on medially placed strap supports, compression of the saphenous nerve can result in numbness along the medial calf. Excessive flexion of the thigh against the groin can injure the obturator and, less commonly, the femoral nerves. Extreme flexion at the thigh can also stretch the sciatic nerve. The most common nerve injuries directly associated with the lithotomy position involve the lumbosacral plexus. Brachial plexus injuries can likewise occur if the upper extremities are inappropriately positioned (eg, hyperextension at the axilla). Compartment syndrome of the lower extremities with rhabdomy-olysis has been reported with prolonged time in the lithotomy position, after which lower extremity nerve damage is also more likely.

The lithotomy position is associated with major physiological alterations. Functionalresidual capacity decreases, predisposing patientsto atelectasis and hypoxia. This effect is amplified by steep Trendelenburg positioning (>30°), which is commonly utilized in combination with the lithot-omy position. Elevation of the legs drains blood into the central circulation acutely and may thereby exacerbate congestive heart failure (or treat a rela-tive hypovolemia). Mean blood pressure and cardiac output may increase. Conversely, rapid lowering of the legs from the lithotomy or Trendelenburg posi-tion acutely decreases venous return and can result in hypotension. Vasodilation from either general or regional anesthesia potentiates the hypotension in this situation, and for this reason, blood pressure measurement should be taken immediately after the legs are lowered.

B. Choice of Anesthesia

General anesthesia—Many patients are appre-hensive about the procedure and prefer to be asleep. However, any anesthetic technique suitable for out patients may be utilized. Because of the short duration (15–20 min) and outpatient settingof most cystoscopies, general anesthesia is often chosen, commonly employing a laryngeal mask air-way. Oxygen saturation should be closely monitored when obese or elderly patients, or those with mar-ginal pulmonary reserve, are placed in the lithotomy or Trendelenburg position.

2. Regional anesthesia—Both epidural andspinal blockade provide satisfactory anesthesia for cystoscopy. However, when regional anesthesia is chosen most anesthesiologists prefer spinal anesthesia because onset of satisfactory sen-sory blockade may require 15–20 min for epidural anesthesia compared with 5 min or less for spinal anesthesia. Some clinicians believe that the sen-sory level following injection of a hyperbaric spi-nal anesthetic solution should be well established (“fixed”) before the patient is moved into the lithot-omy position; however, studies fail to demonstrate that immediate elevation of the legs into lithotomy position following administration of hyperbaric spinal anesthesia either increases the dermatomal extent of anesthesia to a clinically significant de-gree or increases the likelihood of severe hypoten-sion. A sensory level to T10 provides excellent an-esthesia for essentially all cystoscopic procedures.