Felypressin-induced reduction in coronary blood flow and myocardial tissueoxygen tension during anesthesia in dogs

Purpose: To determine whether felypressin reduced myocardial tissue oxygen tension (PmO2). Methods: Seven open-chest dogs were studied under nitrous oxide and isoflur ane anesthesia. Hemodynamic variables including heart rate (HR), blood pres sure (BP), mean pulmonary arterial pressure (MPAP), PmO2 and coronary blood flow (CBF) were continuously recorded. After baseline measurements felypre ssin was infused at 0.15, 0.3, 0.6 and 1.0 IU.hr(-1) in a successive manner . Hemodynamic variables were evaluated at 3, 6, 9 min after the start of ea ch infusion. Results: Felypressin caused reductions in CBF and inner layer PmO2 (int-PmO 2). Decreases in CBF (-23%, P < 0.05) and int-PmO2 (-8%, P < 0.05) observed at low dose (0.151U.hr(-1)) were not accompanied by changes in BP and HR. Negative correlations between cumulative doses of Felypressin (mlU.k(-1)) a nd CBF (% change from base line) (r = -0.69, P < 0.05) or int-PmO2 (% chang e from base line) (r = -0.48, P < 0.05) were observed. Conclusion: Felypressin reduced PmO2 along with minimal changes in HR and B P.