Magnusson L, Zemgulis V, Wicky S, Tydén H, Hedenstierna G
Department of Clinical Physiology, Uppsala University Hospital, Sweden.
Acta Anaesthesiol Scand. 1998 Nov;42(10):1133-8. doi: 10.1111/j.1399-6576.1998.tb05265.x.
Respiratory failure secondary to cardiopulmonary bypass (CPB) remains a major complication after cardiac surgery. We tested the hypothesis that post-CPB lung function impairment can be prevented by continuous positive airway pressure (CPAP) applied during the CPB.
In 6 pigs, CPAP with 5 cmH2O pressure was applied during CPB. Six other pigs served as control, i.e. the lungs were open to the atmosphere during CPB. After median sternotomy, the right atrial appendage as well as the ascending aorta were cannulated. The total CPB duration was 90 min with 45 min cardioplegic arrest. Ventilation-perfusion distribution was measured with the multiple inert gas elimination technique and atelectasis by CT-scanning.
Large atelectasis appeared after CPB, corresponding to 14.5% +/- 5.5 (percent of the total lung area) in the CPAP group and 18.7% +/- 5.2 in the controls (P = 0.20). Intrapulmonary shunt increased and PaO2 decreased after the CPB in both groups.
We conclude that in this pig model post-CPB atelectasis is not effectively prevented by CPAP applied during CPB.
体外循环（CPB）继发的呼吸衰竭仍然是心脏手术后的主要并发症。我们检验了这样一个假设，即在CPB期间应用持续气道正压通气（CPAP）可以预防CPB后肺功能损害。
对6头猪在CPB期间施加5 cmH₂O压力的CPAP。另外6头猪作为对照，即在CPB期间肺与大气相通。经正中胸骨切开术后，分别对右心耳和升主动脉进行插管。CPB总时长为90分钟，其中心脏停搏45分钟。采用多惰性气体排除技术测量通气-灌注分布，并通过CT扫描评估肺不张情况。
CPB后出现大面积肺不张，CPAP组为14.5%±5.5（占全肺面积的百分比），对照组为18.7%±5.2（P = 0.20）。两组在CPB后肺内分流均增加，动脉血氧分压（PaO₂）均降低。
我们得出结论，在此猪模型中，CPB期间应用CPAP不能有效预防CPB后肺不张。
