Haemodynamic consequences of warm cardiac irrigation during cardiac surgery

Following cardiopulmonary bypass (CPB) and prior to closing the chest, some surgeons irrigate the heart and pericardium with warm saline. This prospective study, using each patient as his own control, evaluated the haemodynamic effects of warm (44 +/- 5 degrees C) irrigation on the heart and pericardium following CPB. Following discontinuation of CPB, a Mon-a-therm model 6500 thermocouple monitor measured the myocardial septum and the irrigating fluid temperatures. Immediately before, during and two minutes after irrigation of the heart and pericardium, we measured heart rate (HR), systemic blood pressure (BP), pulmonary artery pressure (PAP), central venous pressure (CVP), thermodilution cardiac output, and calculated systemic vascular resistance (SVR). During warm irrigation, HR increased from 93 +/- 15 to 101 +/- 13 min-1 and systolic BP increased from 111 +/- 17 to 131 +/- 27 mmHg. After irrigation, HR decreased to 96 +/- 12 min-1 with no change in systolic BP. The calculated SVR after irrigation increased to 1117 +/- 413 dynes.sec.cm-5 from the pre-irrigation value of 821 +/- 243 dynes.sec.cm-5, while cardiac index decreased to 2.4 L.min-1.m-2 from its pre-irrigation value of 2.99 L.min-1.m-2. Warm irrigation of the pericardial pouch causes tachycardic and hypertensive responses in patients undergoing cardiac surgery.