Are there acid base changes during transurethral resection of the prostate (TURP)?

UNLABELLED: Acid base status during transurethral resection of the prostate (TURP) has been almost neglected. We therefore measured the acid base status and interpreted the observed changes according to the Stewart approach. The Stewart model focuses more on the influence of serum electrolyte concentrations on acid base changes than does the conventional Henderson-Hasselbalch approach. In 20 patients undergoing TURP, the following variables were determined: PaO(2), PaCO(2), pH(a), actual bicarbonate, standard base excess, serum concentration of sodium, potassium, chloride, lactate, and total protein. A study group (n = 11) and a control group (n = 9) were built, depending on the maximal amount of fluid absorption estimated with the aid of ethanol concentration monitoring in the expired gas. The study group developed a mild acidosis with a decrease in pH from 7.41 to 7.37 (P = 0.037), compared with a very discrete pH decrease from 7.44 to 7.42 in the control group. We found that moderate irrigant absorption during TURP leads to a specific metabolic acidosis. We speculate that larger amounts of irrigant absorption may cause a more severe metabolic acidosis. As the constellation of independently pH regulating variables appears to be typical for TURP, this acidosis could be named "TURP-acidosis." IMPLICATIONS: We measured acid base status in 20 patients undergoing transurethral resection of the prostate comparing a larger fluid absorption group with a minor or no fluid absorption group. We postulate the development of a typical metabolic transurethral resection of the prostate-acidosis caused by irrigant absorption.