Effects of propranolol on human postoperative ileus

Background. The sympathetic nervous hyperactivity present in response to su rgical stress has been implicated as an important component of the postoper ative paralytic ileus. A randomized and prospective study was conducted, ev aluating the effects of the preoperative beta-adrenergic blockade with prop ranolol in schistosomotic patients during the period of postoperative ileus . Methods: The study compared schistosomotic patients submitted, or not, to beta-adrenergic blockade. Basal cardiac frequency was determined and propr anolol was used in a dose of 40 mg twice a day. The dose was adjusted weekl y until a minimum decrease of 20% in cardiac frequency was achieved. Three coupled bipolar electrodes were placed in the left colon in both groups, an d registration of myoelectric activity of the left colon was made twice a d ay during the period of postoperative ileus using a system of data collecti on (DATA Q Series 200). The electric signals were previously amplified, fil tered and separated into Electric Control Activity (ECA) and Electric Respo nse Activity (ERA). Results: The dose of propranolol varied from 80 to 160 mg/day. The proportional decrease in basal heart frequency varied from 20 t o 33%, with an average of 25.4 +/- 3.9% in the propranolol group, maintaini ng a mean of 24.3 +/- 3.6% decrease in the postoperative period. Difference s on clinical recovery of the postoperative ileus were not found. Significa nt differences on electromyographic patterns were not observed between the groups, except for the presence of a greater number of short-duration contr actions in the second postoperative day in the beta-blocked group. Conclusi on: The authors suggest that the preoperative beta-adrenergic blockade with propranolol does not determine myoelectric activity changes that could con tribute to an earlier resolution of postoperative ileus. Copyright (C) 2001 S. Karger AG, Basel.