Birdi I, Regragui I A, Izzat M B, Alonso C, Black A M, Bryan A J, Angelini G D
Bristol Heart Institute, United Kingdom.
Ann Thorac Surg. 1996 Jan;61(1):118-23. doi: 10.1016/0003-4975(95)00881-0.
Pulmonary dysfunction is one aspect of the postoperative morbidity associated with cardiopulmonary bypass. Normothermic systemic perfusion can result in shorter intubation times, which have been attributed to improved pulmonary gas exchange, but the influence of perfusion temperature on pulmonary gas exchange itself is not known.
Pulmonary gas exchange was assessed using alveolar-arterial oxygen pressure gradients in 45 patients undergoing routine coronary revascularization who were randomized to undergo cardiopulmonary bypass at 28 degrees C, 32 degrees C, or 37 degrees C. This was part of a more comprehensive study of the effects of temperature on bodily systems. The gradients were estimated preoperatively with the patients breathing air, again over a period between 2 and 4 hours postoperatively during mechanical ventilation with three different oxygen concentrations (30%, 40%, and 60%), and again 1 hour after extubation while breathing the same three oxygen concentrations.
Preoperative alveolar-arterial oxygen pressure gradients on air were 24.4 +/- 8.2 mm Hg (mean +/- standard deviation) (28 degrees C), 24.5 +/- 20.4 mm Hg (32 degrees C), and 20.5 +/- 9.5 mm Hg (37 degrees C). Postoperatively, during ventilation and after rewarming, the gradients increased with the increase in inspired oxygen fraction concentrations (30% to 60%) from 67.1 +/- 12.0 mm Hg to 193.1 +/- 30.5 mm Hg (28 degrees C), from 76.4 +/- 20.6 mm Hg to 246.7 +/- 47.7 mm Hg (32 degrees C), and from 79.0 +/- 18.0 mm Hg to 222.9 +/- 40.5 mm Hg (37 degrees C), respectively. A similar pattern was noted 1 hour after extubation, when the gradients increased from 72.4 +/- 12.5 mm Hg to 256.6 +/- 26.5 mm Hg (28 degrees C), from 75.7 +/- 13.9 mm Hg to 252.7 +/- 38.3 mm Hg (32 degrees C), and from 69.1 +/- 19.3 mm Hg to 253.1 +/- 33.0 mm Hg (37 degrees C). There were no significant differences in alveolar-arterial oxygen pressure gradient between the three groups during ventilation or after extubation.
Cardiopulmonary bypass perfusion temperature does not influence alveolar-arterial oxygen pressure gradients in the first 12 hours after routine coronary artery bypass grafting in patients with uncompromised pulmonary and left ventricular function.
肺功能障碍是与体外循环相关的术后发病的一个方面。常温全身灌注可使插管时间缩短，这归因于肺气体交换的改善，但灌注温度对肺气体交换本身的影响尚不清楚。
在45例行常规冠状动脉血运重建的患者中，使用肺泡-动脉氧分压梯度评估肺气体交换情况，这些患者被随机分配接受28℃、32℃或37℃的体外循环。这是一项关于温度对身体系统影响的更全面研究的一部分。术前在患者呼吸空气时估计梯度，术后在机械通气期间再次估计，持续2至4小时，使用三种不同的氧浓度（30%、40%和60%），拔管后1小时再次估计，此时呼吸相同的三种氧浓度。
术前呼吸空气时的肺泡-动脉氧分压梯度分别为（28℃）24.4±8.2mmHg（平均值±标准差）、（32℃）24.5±20.4mmHg和（37℃）20.5±9.5mmHg。术后，在通气和复温期间，随着吸入氧分数浓度从30%增加到60%，梯度增加，（28℃）从67.1±12.0mmHg增加到193.1±30.5mmHg，（32℃）从76.4±20.6mmHg增加到246.7±47.7mmHg，（37℃）从79.0±18.0mmHg增加到222.9±40.5mmHg。拔管后1小时观察到类似模式，此时梯度（28℃）从72.4±12.5mmHg增加到256.6±26.5mmHg，（32℃）从75.7±13.9mmHg增加到252.7±38.3mmHg，（37℃）从69.1±19.3mmHg增加到253.1±33.0mmHg。三组在通气期间或拔管后的肺泡-动脉氧分压梯度无显著差异。
对于肺和左心室功能正常的患者，在常规冠状动脉搭桥术后的前12小时内，体外循环灌注温度不影响肺泡-动脉氧分压梯度。
