Plasma esterase activities in young and old patients undergoing open inguinal hernia repair

Previous research has shown substantial decrements in enzymes of drug metabolism (esterases) in older patients following fracture neck of femur and hip replacement surgery. The main aim of this study was to examine the effect of open inguinal hernia repair on the activities of four plasma esterases in old and young patients. Seventeen older patients (mean age+/-S.E.M. was 67.6+/-1.8) and 12 young patients (mean age+/-S.E.M. was 38+/-3.3) undergoing open hernia repair for clinical reasons were recruited. The activities of plasma benzoylcholinesterase, butyrylcholinesterase, acetylcholinesterase, and aspirin esterase were determined spectrophotometrically, before the operation, 1 day post operatively and 1 week later. There was no significant effect of hernia repair surgery on any of the four enzymes measured in young or old patients. Neither was there any significant difference in enzyme activity between young and old at any of the three time points. Hernia repair surgery is not associated with decrements in enzymes of drug metabolism in man. This contrasts with the previous findings in hip replacement surgery.