ORTHOSTATIC HYPOTENSION DURING POSTOPERATIVE CONTINUOUS THORACIC EPIDURAL BUPIVACAINE MORPHINE IN PATIENTS UNDERGOING ABDOMINAL-SURGERY

Fifty patients undergoing colonic surgery received combined thoracic e pidural and general anesthesia followed by continuous epidural bupivac aine 0.25% and morphine 0.05 mg/mL, 4 mL/h, for 96 h postoperatively p lus oral tenoxicam 20 mg daily. Heart rate (HR) and arterial blood pre ssure (BP) were measured at supine rest, during orthostatic stress, an d after walking prior to and 24, 48, and 72 h after surgery. Systolic BP at rest was significantly lower 24 h and 48 h postoperatively compa red to preoperatively (P less than or equal to 0.008); 16 vs 6 patient s presented resting systolic BP values < 100 mm Hg (lower range, 70 mm Hg) post- versus preoperatively (P = 0.048). During orthostatic stres s the decrease in systolic BP and concomitant increase in HR was simil ar post-versus preoperatively (BP, P greater than or equal to 0.3; HR, P > 0.34) and 12 vs 8 patients (P = 0.45) experienced a systolic BP d ecrease > 20 mm Hg post- versus preoperatively. After walking systolic BP was significantly lower postoperatively compared with preoperative ly (P less than or equal to 0.01). Epidural infusion was discontinued in three patients due to either persisting resting or orthostatic hypo tension. There was no correlation between ASA classification, intraope rative bleeding, or postoperative dizziness and incidence of orthostat ic hypotension. The re suits suggest that patients undergoing abdomina l surgery and treated with continuous small-dose thoracic epidural bup ivacaine-morphine are subjected to a decrease of BP at rest and during mobilization, but not to an extent that seriously impairs ambulation in most patients.