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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, METHODS, METHODS, METHODS, RESULTS. Meshes: Acetylcholine, Aged, Cardiopulmonary Bypass, Extracorporeal Circulation, Female, Hemodynamics, Humans, Male, Middle Aged, Myocardial Reperfusion Injury, Premedication, Protamines, Pulmonary Circulation, Vascular Resistance.
user
Is altered reactivity to acetylcholine in the pulmonary circulation after cardiopulmonary bypass part of reperfusion injury? Context: To investigate whether a time sequence of acetylcholine (ACH) reactivity indicative of endothelial reperfusion injury could be demonstrated in the pulmonary circulation in patients after cardiopulmonary bypass (CPB). Prospective study. Operating theater and intensive care unit of a university hospital. 10 ASA physical status III and IV patients with ischemic or valvular heart disease. Pulmonary vascular resistance index (PVRI) was measured before and during an infusion of ACH. This procedure was done after induction of anesthesia but before surgery, immediately after weaning from bypass, and at 1 to 1.5 and 4 hours after CPB. ACH caused a decrease in PVRI before (p < 0.01) and directly after CPB (p < 0.05) but not at 1 to 1.5 or 4 hours after bypass.
assistant
The maintained reactivity to ACH directly after CPB, followed by no reaction at 1 to 1.5 and 4 hours, was in agreement with experimental findings and indicates endothelial reperfusion injury caused by the period with no blood flow through the pulmonary artery during CPB and subsequent reperfusion. Final Decision: yes