title: Lung management during cardiopulmonary bypass: is continuous positive airways pressure beneficial?
abstract: It is not clear if the use of continuous positive airway pressure (CPAP) during cardiopulmonary bypass (CPB) improves lung function after cardiac surgery. We have measured alveolar-arterial oxygen partial pressure difference (PAO2-PaO2) in 61 patients undergoing elective coronary artery bypass surgery. We studied three groups of patients: in group 1 the lungs were disconnected from the breathing system (no CPAP) during CPB; in group 2, 5 cm H2O CPAP with air was applied to the lungs; in group 3, 5 cm H2O of CPAP was applied with 100% oxygen. (PAO2-PaO2) was measured before CPB and then at 30 min, 4 h and 8 h after CPB. Compared with group 1 (no CPAP), (PAO2-PaO2) was significantly smaller in groups 2 and 3 at 30 min (P = 0.036), but not at 4 h and 8 h after CPB (P = 0.32, P = 0.96). The time to extubation (P = 0.42) and early extubation (P = 0.87) were not affected by the use of CPAP. The results of this study do not support the use of CPAP during CPB as a mechanism of improving lung function after cardiac surgery.
authors.affiliation: Department of Anaesthesia, Alfred Hospital, Prahran, Victoria, Australia.
authors.forename: C B
authors.initials: CB
authors.lastname: Berry
authors.forename: P J
authors.initials: PJ
authors.lastname: Butler
authors.forename: P S
authors.initials: PS
authors.lastname: Myles
mesh_terms: D000328:Adult; D000368:Aged; D002315:Cardiopulmonary Bypass; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007430:Intraoperative Care; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000032:analysis / Q000097:blood; D010313:Partial Pressure; D011175:Positive-Pressure Respiration; D011184:Postoperative Period; D011650:Pulmonary Alveoli / Q000737:chemistry; D011659:Pulmonary Gas Exchange
chemical_list: D010100:Oxygen