Marik P E, Kaufman D
Department of Critical Care Medicine, St. Vincent Hospital, Worcester, Mass., USA.
Chest. 1996 Apr;109(4):1038-42. doi: 10.1378/chest.109.4.1038.
To evaluate the effect of neuromuscular paralysis on systemic and splanchnic oxygen utilization in patients in respiratory failure during controlled mechanical ventilation.
A university-affiliated teaching hospital.
Mechanically ventilated patients, who were undergoing hemodynamics monitoring and who had a gastric intramucosal pH (pHi) of less than 7.35, were studied. Prior to paralysis, the patients were sedated with lorazepam and morphine to standard end points, and the cardiac output and oxygenation were optimized. The patients were then paralyzed with doxacurium and the ventilator rate adjusted to keep the PaCO2 at baseline value. The hemodynamic and oxygenation profile and pHi were determined prior to paralysis and repeated 2 to 2.5 h later.
Eight patients were studied; their mean age was 63 +/- 8 years and acute physiology and chronic health evaluation II score was 22 +/- 4. The mean fraction of inspired oxygen, positive end-expiratory pressure, and venous admixture ratio prior to the study was 0.7 +/- 0.14, 11.8 +/- 2.4 cm H2O, and 26 +/- 9%, respectively. Prior to paralysis, the mean set assist controlled ventilation rate was 15 +/- 2 breaths/min and the patient rate was 23 +/- 5 breaths/min. With neuromuscular paralysis, the cardiac index fell from 4.6 +/- 2.2 to 4.3 +/- 2.4 L/min/m2 (p=0.1), the oxygen delivery fell from 537 +/- 129 to 471 +/- 95 mL/min/m2 (p=0.03), and the oxygen consumption and extraction ratio fell from 200 +/ 77 to 149 +/- 35 mL/min/m2 (p=0.03) and 36 +/- 5 to 31 +/- 10, respectively (p=0.2). The pHi increased from 7.21 +/- 0.16 to 7.29 +/- 0.1 (p=0.02).
In critically ill patients in respiratory failure, neuromuscular paralysis decreased whole body oxygen consumption and increased pHi. Presumably, by eliminating the work of breathing, there is a redistribution of blood flow from the respiratory muscles to the splanchnic and other nonvital vascular beds.
评估在控制机械通气期间，神经肌肉麻痹对呼吸衰竭患者全身及内脏氧利用的影响。
一所大学附属医院。
对正在接受血流动力学监测且胃黏膜内pH值（pHi）小于7.35的机械通气患者进行研究。在麻痹前，用劳拉西泮和吗啡将患者镇静至标准终点，并优化心输出量和氧合情况。然后用多沙库铵使患者麻痹，并调整呼吸机频率以维持动脉血二氧化碳分压（PaCO2）在基线值。在麻痹前测定血流动力学、氧合情况及pHi，并在2至2.5小时后重复测定。
研究了8例患者；他们的平均年龄为63±8岁，急性生理与慢性健康状况评分系统II（APACHE II）评分为22±4。研究前吸入氧分数、呼气末正压及静脉血掺杂率的平均值分别为0.7±0.14、11.8±2.4厘米水柱及26±9%。在麻痹前，设定的辅助控制通气频率平均值为15±2次/分钟，患者自主呼吸频率为23±5次/分钟。发生神经肌肉麻痹后，心脏指数从4.6±2.2降至4.3±2.4升/分钟/平方米（p = 0.1），氧输送量从537±129降至471±95毫升/分钟/平方米（p = 0.03），氧耗量及氧摄取率分别从200±77降至149±35毫升/分钟/平方米（p = 0.03）及从36±5降至31±10（p = 0.2）。pHi从7.21±0.16升至7.29±0.1（p = 0.02）。
在呼吸衰竭的重症患者中，神经肌肉麻痹可降低全身氧耗量并升高pHi。据推测，通过消除呼吸做功，血流从呼吸肌重新分布至内脏及其他非重要血管床。
