• B S Rasmussen, J Sollid, S E Rees, S Kjaergaard, D Murley, and E Toft.
• Department of Anaesthesia, Centre for Cardiovascular Research, Aalborg Hospital, Aarhus University, Denmark. an.bsr@nja.dk
• Acta Anaesthesiol Scand. 2006 Jan 1; 50 (1): 64-71.

BackgroundLung function is often impaired after cardiac surgery performed under cardiopulmonary bypass (CPB). Normothermic CPB has become more common, but it remains unknown whether it reduces post-operative lung function compared with hypothermic CPB. The aim of this study was to investigate oxygenation within the first 120 h after systemic hypothermia and normothermia under CPB.MethodsThirty patients undergoing coronary artery bypass grafting (CABG) were randomized to either hypothermic (32 degrees C) or normothermic (36 degrees C) CPB. Oxygenation was studied by a simple method for the estimation of intrapulmonary shunt and ventilation-perfusion (V/Q) mismatch pre-operatively and 4, 48 and 120 h post-operatively by changing Fio2 in four to six steps. V/Q mismatch was described with DeltaPo2 (normal values, 0-2.38 kPa).ResultsShunt and V/Q mismatch (DeltaPo2) increased post-operatively in both groups (P<0.01), with no differences between the groups, and with the nadir values 48 h after surgery, i.e. shunt of 15% (5.8-25%) and DeltaPo2 of 3.0 kPa (0.8-14 kPa) [values given as median (range)].ConclusionsImpaired oxygenation is prevalent and prolonged following CABG, with equal intensity after hypothermic and normothermic CPB.

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