胸腔手术时肺循环的右向左分流

目的探讨胸腔手术时肺循环的右向左分流 (right to lefttranspulmonaryshuntfraction ,Qs/Qt)。 方法直接测定肺泡气氧分压和动脉血氧分压 ,计算肺泡 动脉氧分压差 (alveolar arterialoxygentensiondifference ,A aDO2 )和Qs/Qt,观察 2 6例胸腔手术对Qs/Qt的影响。结果由平卧位到侧卧位A aDO2 和Qs/Qt无明显变化 ,开胸后A aDO2 和Qs/Qt增加 ,开胸 1hQs/Qt达 (12 .16± 5 .5 7) % ,动脉血气分析未发现缺氧情况。结论胸腔手术开胸后肺循环的右向左分流增加 ,并随手术时间延长有加重趋势

RIGHT-TO-LEFT TRANSPULMONARY SHUNT FLOW DURING THORACIC SURGERY

Objective　To explore the right-to-left transpulmonary shunt flow in thoracic surgery.Methods　The oxygen tensions of alveolar gas and arterial blood were measured with blood gas analysis settings in 26 patients scheduled for thoracic surgery during the procedure. The alveolar-arterial oxygen tension difference (A-aDO2) and right-to-left shunt fraction (Qs/Qt) was calculated before and 10 min after lateral decubitus positioning, 15 min and 60 min after thoracotomy.Results　There were no significant changes in A-aDO2 and Qs/Qt after the patients were positioned from supine to lateral decubitus. Both A-aDO2 and Qs/Qt increased after the chest was opened, which could be aggregated as the procedure prolonged. The Qs/Qt reached (12.16±5.57) % at 60 min of thoracotomy. However, no hypoxemia occurred during the operation.Conclusion　Shunt fraction of transpulmonary flow was significantly increased by thoracotomy and deteriorated as the open chest prolonged.