In men undergoing prostate surgery, excessive fluid absorption can lead to dangerously low sodium levels. Adding a small amount of glucose to the irrigation fluid used during surgery can help anesthesiologists to prevent this rare but potentially serious complication, reports a study in the December issue of Anesthesia & Analgesia, official journal of the International Anesthesia Research Society (IARS).
The new technique provides a simple but effective solution to a challenging problem: how to monitor fluid status during transurethral resection of the prostate (TURP), the most common type of surgery for men with enlarged prostate (benign prostatic hyperplasia). The study was performed by Dr. Robert G. Hahn and colleagues of Karolinska Institutet, Stockholm.
'Sweet Solution' to a Complex Problem
During the TURP procedure, a constant flow of fluid is used to irrigate the bladder. In the past, irrigation was performed using a fluid that contained no sodium—this posed a risk of potentially fatal hyponatremia (low sodium level) if the body absorbed too much fluid. In recent years, surgeons have switched to an irrigation fluid containing normal saline, which can be absorbed in large amounts without dangerous effects on the blood sodium level.
"But, as often happens in medicine, new solutions present new problems," says Dr. Steven L. Shafer of Columbia University, Editor-in-Chief of Anesthesia & Analgesia. "Typically surgeons cannot tell that large amounts of fluid are being absorbed during prostate surgery. They rely on the anesthesiologist to monitor the patient's mental status and sodium level. The use of normal saline for irrigation invalidates these traditional measures of excessive fluid absorption."
To deal with this problem, Dr. Hahn and colleagues developed a new approach: adding a small amount of glucose (one percent) to the irrigation fluid. In the new study, they monitored changes in glucose and sodium levels in 250 patients who received the glucose solution for irrigation during TURP. The results showed that an increase in glucose level was just as good an indicator of the patient's fluid status as a decrease in sodium level.
An additional study was performed in ten healthy volunteers, who received about one and a half liters of a solution with a small amount of additional glucose added. Using sophisticated models of body fluid, Dr. Hahn and his team were able to show that the change in glucose levels was a reliable indicator of the amount of extra fluid in the patient's blood vessels.
"What this means for the patient is that, regardless of the fluid that the surgeon uses during prostate surgery, the anesthesiologist can simply measure the glucose level to monitor the amount of fluid absorbed," explains Dr. Shafer. "This 'sweet solution' to monitoring patients for fluid overload during prostate surgery provides useful guidance to the surgical and anesthesia teams, increasing the safety of this common surgical procedure."
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