The effect of intestinal preparation on fluid and electrolyte balance.

Abstract

Abstract It has been suggested that circulatory instability in elderly patients after the induction of anaesthesia is frequently accounted for by undiagnosed hypovolaemia, particularly in cases of intestinal cancer when preoperative mechanical bowel preparation has been used. In the present study measurements were made in 25 patients undergoing mechanical bowel preparation for large-bowel cancer surgery. Blood-volume measurements remained within normal limits after bowel preparation, and in 5 patients no change was found in total body exchangeable sodium, extracellular fluid volume, and plasma volume measured before and after bowel preparation. Fluid and electrolyte balance studies in 11 cases showed that renal conservation of sodium occurred in the 24 hours preceding surgery and this is probably accounted for by diminished dietary intake. Circulatory instability after the induction of anaesthesia was commonly encountered but in most cases this was not the result of preoperative dehydration.