What other complications can occur during a TURP?
Approximately 7% of all patients undergoing a TURP suffer a major complication. The 30-day mortality rate has been estimated to be 0.1–0.8%. This is a marked improve-ment over earlier studies that showed a mortality rate of approximately 2.5% during the 1960s. Patients undergoing a TURP are often advanced in age, and have coexisting cardiopulmonary disorders making them more likely to experience complications. Since many patients are on chronic diuretics, they are often dehydrated with electrolyte abnormalities preoperatively.
Other complications associated with this procedure are as follows:
Bladder perforation occurs in approximately 1% of all TURP procedures. It may be caused by overdistention of the bladder with irrigating fluid, or as a result of surgical instrumentation. An early sign of bladder perforation is a decrease in return of irrigating fluid from the bladder. The abdomen will become distended and often rigid. If the procedure is being performed under a regional anesthetic, the patient may complain of pain and/or experience nausea and vomiting. Hypotension followed by hypertension is common.
Most perforations are extraperitoneal and benign in nature. This type of perforation causes pain in the periumbilical region. However, pain in the upper abdomen or referred pain to the shoulder may be a sign of an intraperitoneal perforation, a potentially fatal compli-cation. Diagnosis should quickly be confirmed by cysto-urethrography and treated with a suprapubic cystostomy.
The prostate is a highly vascular organ. Since a large amount of irrigation is used, it is difficult to determine the actual blood loss. Intraoperative blood loss corresponds to the size of the gland as well as to the resection time. It has been estimated that the blood loss is approximately 2–5 ml/min of resection time and 20–50 ml/g of prostate tissue. Blood loss is linearly related to prostate size up to 35 grams, at which point blood loss tends to exceed the linear correlation. Patients with resection times of greater than 90 minutes or a prostate size of more than 60 grams have been found to have a significant increase in morbidity associated with bleeding.
Subclinical coagulopathy occurs in approximately 6% of patients undergoing a TURP, while clinical coagulopathy occurs approximately 1% of the time. This condition seems to correlate with the mass of the resected prostatic tissue. It is more likely to occur if the resected tissue is greater than 35 grams. Coagulopathy may be due to a dilution of coagulation factors and platelets.
Primary fibrinolysis has also been implicated as a cause of coagulopathy. Plasminogen activator, which is responsi-ble for converting plasminogen into plasmin, is released during these procedures. The treatment of choice for primary fibrinolysis is ε-aminocaproic acid.
Secondary fibrinolysis may occur as a result of dissemi-nated intravascular coagulopathy (DIC). DIC is caused by the systemic absorption of prostate tissue, which is rich in thromboplastin. Proof of this theory lies in the fact that these patients often have a low level of plasminogen activa-tor, platelets, and fibrinogen – common findings in DIC. If DIC is suspected, the treatment is symptomatic. Fluid and blood products are administered as needed. Heparin administration may be beneficial.
Transient Bacteremia and Septicemia
The prostate, rich in bacteria, may cause a postoperative bacteremia via the prostatic venous sinusoids. An indwelling urinary catheter will enhance the risk. Approximately 6–7% of patients will go on to develop sepsis. Treatment consists of antibiotics and supportive care.
Toxicity of Irrigating Fluids
The major toxicity of the irrigation fluids used today is secondary to massive absorption causing fluid overload, hyponatremia, and hypo-osmolality. The incidence of hypo-osmolality and its associated neurologic sequelae has decreased since the use of nonelectrolyte iso-osmotic irri-gating fluids. However, fluid overload and hyponatremia still remain a problem. As much as 8 liters of irrigating fluid may be absorbed during a TURP, causing an average weight gain of about 2 kg. Twenty to thirty percent of this fluid is absorbed directly into the vascular space. The remainder is absorbed into the periprostatic and the peri-toneal space (interstitial space). Several factors contribute to the rate of absorption of irrigating fluid by the patient. These include the prostate size, integrity of the prostatic capsule, and the height of the irrigating fluid container. Greater amounts of irrigating fluid are absorbed when the prostate is large because of its richer blood supply, and if the prostate capsule is violated.
There are maneuvers that may be carried out to limit the amount of irrigating fluid absorbed. The first is to restrict the height of the fluid container above the surgical field. This will decrease the hydrostatic pressure driving the fluid into the sinuses. When the height of the bag is greater than 60 cm, absorption is greatly enhanced. The sec-ond is to limit the length of the resection time to less than 150 minutes, as some investigators have found that 10–30 cc of irrigation fluid is absorbed per minute of resection time.
Sorbitol and mannitol, both sugar alcohols, have been associated with the development of lactic acidosis and hyper-glycemia. Specific effects of glycine will be discussed later.
Patients may develop hypothermia under either general or neuraxial anesthesia. This can be exacerbated by using irrigating fluids at room temperature. Using warmed irrigating fluid can decrease heat loss and shivering.
It is a theoretical concern that warming the irrigating fluids would cause vasodilation, thereby increasing blood loss. However, this has not been shown to be a clinical concern. In fact, since hypothermia may cause shivering, which increases venous pressure, there may be an increased blood loss if the irrigating fluids are not warmed.