VASOPRESSOR HORMONE RESPONSE FOLLOWING MESENTERIC TRACTION DURING MAJOR ABDOMINAL-SURGERY

Background: We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI(2) ) release in patients undergoing abdominal surgery with a combined gen eral and epidural anesthesia. Methods: In a prospective, randomized, p lacebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combi ned with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and m easured 6-keto-PGF(1 alpha) (stabile metabolite of PGI(2)), TXB2 (stab ile metabolite of thromboxane A(2)) active renin, and arginine vasopre ssin (AVP) plasma concentrations by radioimmunoassay. Catecholamine le vels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results: Following MT, arterial hypotension occurred along with a substantial PGI, release. This was completely a bolished by ibuprofen administration. Although plasma levels of 6-keto -PGF(1 alpha) (1133 (708) vs. 60 (3) ng/L, median (median absolute dev iation), P=0.0001, placebo vs. ibuprofen) remained significantly eleva ted, blood pressure was restored within 30 min after MT in the placebo group. At the same Feint in time plasma concentrations of TXB2 (164 ( 87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41+/-(18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P=0.001) were significantly higher in placeb o-treated patients. Conclusion: Under combined general and epidural an esthesia arterial hypotension following MT due to endogenous PGI(2) re lease is associated with enhanced release of AVP, active renin, epinep hrine and thromboxane A(2), presumably contributing to hemodynamic sta bility within 30 min after MT.