Glucose as a marker of fluid absorption in bipolar transurethral surgery.

BACKGROUND: Historically, a reduced serum sodium concentration has been used to diagnose absorption of electrolyte-free irrigating fluid during transurethral resection of the prostate (TURP). In bipolar TURP, the irrigating solution contains electrolytes, thus invalidating the serum sodium method. In this study, we investigated whether glucose can be used to diagnose the absorption of irrigating fluid during TURP procedures.

METHODS: The serum glucose and sodium concentrations were measured in 250 patients undergoing monopolar TURP using either 1.5% glycine or 5% glucose for urinary bladder irrigation. The glucose kinetics was analyzed in 10 volunteers receiving a 30-min infusion of 20 mL/kg of acetated Ringer's solution with 1% glucose. These data were then used in computer simulations of different absorption patterns that were summarized in a nomogram for the relationship between the glucose level and administered fluid volume.

RESULTS: There was a statistically significant inverse linear relationship between the decrease in serum sodium and the increase in glucose levels after absorption of 5% glucose during TURP (r(2) = 0.80). The glucose concentration increased, from 4.6 (sd 0.4) to 8.3 (0.9) mmol/L, during the experimental infusions. Regardless of the absorption pattern, all simulations indicated that the uptake of 1 L of fluid containing 1% glucose corresponded to an increase in the glucose level of 3.7 (sd 1.6) mmol/L at the end of surgery, whereas 2 L yielded an increase of 6.9 (1.7) mmol/L.

CONCLUSIONS: In bipolar TURP, the addition of glucose to a concentration of 1% in the electrolyte-containing irrigation fluid can be used as a tracer of absorption that is comparable with measuring serum sodium after monopolar TURP.