Case Report

Case Study: Use of Two Parallel Oxygenators in a 159 Kilogram Patient during Normothermic Cardiopulmonary Bypass

St. Michaels Hospital, Toronto, Ontario, Canada

^* Address correspondence to: Carole Hamilton, CCP, CPC, Maenherstr 16, 81375 Muenchen, Germany

Abstract

There have been few reports describing the perfusion of large patients with relevance to oxygen transfer and oxygen consumption (1,2). This report describes the technique of two oxygenators connected in parallel on a 33 year old male who presented to the operating room for repair of an acute dissecting type A ascending aortic aneurysm. The patient's weight was 159 kg, height 189 cm, and BSA 2.88 m². The calculated blood flow, using a cardiac index of 2.4 L/min/m² was 6.9 L/min. The theoretical oxygen consumption was calculated as 375 ml/min. The oxygen transfer of the oxygenator is rated at 350 ml/min at a flowrate of 6 L/min. To deal with the possibility of inadequate oxygenation in this large patient, due to insufficient oxygenator surface area, the decision was made to use a second oxygenator in parallel.

The pump was set-up in the usual fashion and the second oxygenator was connected into the existing circuit and de-aired. It was then clamped out of the circuit, ready for future use. Cardiopulmonary bypass was instituted via femoral arterial and right atrial cannulation. Standard normothermic bypass and warm cardioplegia techniques were used after initiation of cardiopulmonary bypass. Venous oxygen saturation indicated insufficient oxygenation within three minutes on pump. The second oxygenator was immediately brought into use resulting in normal physiologic levels within ninety seconds. The patient underwent a successful Cabral procedure, with a total cardiopulmonary bypass time of one hundred and ten minutes. There were no problems separating the patient from bypass.