Sacuto Yann, Sacuto Thierry
1 Department of Anesthesiology and Intensive Care, Rouen University Hospital, Rouen, France.
2 Department of Anesthesiology and Intensive Care, Marie Lannelongue Hospital, Le Plessis Robinson, France (location of the study).
Perfusion. 2017 Nov;32(8):631-638. doi: 10.1177/0267659117713592. Epub 2017 Jun 3.
Lung dysfunction following cardiac surgery is currently viewed as the consequence of atelectasis and lung injury. While the mechanism of atelectasis has been largely detailed, the pathogenesis of lung injury after cardiopulmonary bypass is still unclear. Based upon clinical and experimental studies, we hypothesized that lungs could be injured through a mechanical phenomenon.
We recorded pulmonary compliance at six key moments of a heart operation in 62 adult patients undergoing elective cardiac surgery. We focused on the period lasting from anesthetic induction to aorta unclamping. We calculated the variation of static and dynamic pulmonary compliance caused by thorax opening; ΔCstat1 and ΔCdyn1 and that caused by cardiopulmonary bypass, ΔCstat2 and ΔCdyn2. Blood gases were performed under standardized ventilation after anesthetic induction and after surgical closure. The PaO/FiO ratio was calculated. ∆PaO/FiO was the criterion for lung dysfunction. We compared ΔCstat1 and ΔCdyn1 with both ∆PaO/FiO and, respectively, ΔCstat2 and ΔCdyn2.
Static and dynamic compliance increased with the opening of the thorax and decreased with the start of cardiopulmonary bypass. The PaO/FiO ratio diminished after surgery. ΔCstat1 and ΔCdyn1 were negatively correlated with both ∆PaO/FiO (r=-0.42; p<0.001 and r=-0.44; p<0.001) and, respectively, with ΔCstat2 and ΔCdyn2 (r=-0.59; p<0.001 and r=-0.53; p<0.001).
Increased pulmonary compliance induced by the opening of the thorax is correlated with worsened intrapulmonary shunt after cardiopulmonary bypass. A mechanical phenomenon could be partly responsible for post-operative hypoxemia.
心脏手术后的肺功能障碍目前被视为肺不张和肺损伤的结果。虽然肺不张的机制已基本明确，但体外循环后肺损伤的发病机制仍不清楚。基于临床和实验研究，我们推测肺可能通过一种机械现象受到损伤。
我们记录了62例接受择期心脏手术的成年患者在心脏手术六个关键时间点的肺顺应性。我们重点关注从麻醉诱导到主动脉阻断期间。我们计算了开胸引起的静态和动态肺顺应性变化；ΔCstat1和ΔCdyn1，以及体外循环引起的变化，ΔCstat2和ΔCdyn2。在麻醉诱导后和手术结束后，在标准化通气下进行血气分析。计算PaO/FiO比值。∆PaO/FiO是肺功能障碍的标准。我们将ΔCstat1和ΔCdyn1分别与∆PaO/FiO以及ΔCstat2和ΔCdyn2进行比较。
静态和动态顺应性随着开胸而增加，随着体外循环的开始而降低。术后PaO/FiO比值降低。ΔCstat1和ΔCdyn1与∆PaO/FiO均呈负相关（r = -0.42；p < 0.001和r = -0.44；p < 0.001），分别与ΔCstat2和ΔCdyn2呈负相关（r = -0.59；p < 0.001和r = -0.53；p < 0.001）。
开胸引起的肺顺应性增加与体外循环后肺内分流恶化相关。一种机械现象可能部分导致术后低氧血症。
