Vinayak Ajeet G, Gehlbach Brian, Pohlman Anne S, Hall Jesse B, Kress John P
Section of Pulmonary and Critical Care Medicine, University of Chicago, Chicago, IL, USA.
Crit Care Med. 2006 Jun;34(6):1668-73. doi: 10.1097/01.CCM.0000218412.86977.40.
Permissive hypercapnia (PH) may result from mechanical ventilation (MV) strategies that intentionally reduce minute ventilation. Sedative doses required to tolerate PH have not been well characterized. With increased attention to lung-protective ventilation, characterization of sedative requirements with PH and determination of sedative dose changes with PH are needed.
Retrospective analysis.
Tertiary care university hospital.
We evaluated 124 patients randomized in a previous study to either propofol or midazolam. PH was employed in ten of 60 patients receiving propofol and 13 of 64 patients receiving midazolam.
We analyzed dosing of propofol and midazolam in patients undergoing PH through a retrospective analysis of an existing database on MV patients. Total sedative (propofol and midazolam) dose was recorded for the first three days of MV. Linear regression analysis (dependent variable: sedative dose) was used to analyze the following independent variables: PH, age, gender, daily sedative interruption, type of respiratory failure, presence of hepatic and/or renal failure, Acute Physiology and Chronic Health Evaluation II score, morphine dose, and Ramsay sedation score.
Propofol dose was higher in PH patients (42.5+/-16.2 vs. 27.0+/-15.3; p=.02); Midazolam dose did not differ between PH and non-PH patients (0.05 [0.04, 0.14] vs. 0.05 [0.03, 0.07]; p=.17). By univariate linear regression analysis, propofol dose was significantly dependent on PH, age, type of respiratory failure, morphine dose, and Ramsay score, with PH (regression coefficient, 11.7; 95% confidence interval, 1.2-22.7; p=.03) and age (regression coefficient, -0.3; 95% confidence interval -0.5 to -0.08; p=.005) remaining significant by multivariate linear regression. By univariate linear regression analysis, midazolam dose was dependent on age, morphine dose, and Ramsay score, but not PH; only morphine dose (regression coefficient, 0.44; 95% confidence interval, 0.22-0.67 for a 0.1-unit increase in morphine dose; p<.001) was significant by multivariate linear regression.
We conclude that higher doses of propofol but not midazolam are required to sedate patients managed with PH.
允许性高碳酸血症（PH）可能源于故意降低分钟通气量的机械通气（MV）策略。耐受PH所需的镇静剂量尚未得到充分描述。随着对肺保护性通气的关注度增加，需要明确PH时的镇静需求特征以及PH时镇静剂量的变化情况。
回顾性分析。
三级医疗大学医院。
我们评估了先前一项研究中随机接受丙泊酚或咪达唑仑治疗的124例患者。60例接受丙泊酚治疗的患者中有10例采用了PH，64例接受咪达唑仑治疗的患者中有13例采用了PH。
我们通过对现有的MV患者数据库进行回顾性分析，分析了接受PH治疗患者的丙泊酚和咪达唑仑给药情况。记录MV前三天的总镇静（丙泊酚和咪达唑仑）剂量。采用线性回归分析（因变量：镇静剂量）来分析以下自变量：PH、年龄、性别、每日镇静中断情况、呼吸衰竭类型、肝和/或肾功能衰竭的存在、急性生理与慢性健康状况评分II、吗啡剂量和 Ramsay镇静评分。
PH患者的丙泊酚剂量较高（42.5±16.2 vs. 27.0±15.3；p = 0.02）；PH患者与非PH患者的咪达唑仑剂量无差异（0.05 [0.04, 0.14] vs. 0.05 [0.03, 0.07]；p = 0.17）。通过单变量线性回归分析，丙泊酚剂量显著依赖于PH、年龄、呼吸衰竭类型、吗啡剂量和 Ramsay评分，多变量线性回归分析显示PH（回归系数，11.7；95%置信区间，1.2 - 22.7；p = 0.03）和年龄（回归系数，-0.3；95%置信区间 -0.5至 -0.08；p = 0.005）仍具有显著性。通过单变量线性回归分析，咪达唑仑剂量依赖于年龄、吗啡剂量和 Ramsay评分，但不依赖于PH；多变量线性回归分析显示只有吗啡剂量（回归系数，0.44；95%置信区间，吗啡剂量每增加0.1单位为0.22 - 0.67；p < 0.001）具有显著性。
我们得出结论，对于接受PH治疗的患者，需要更高剂量的丙泊酚而非咪达唑仑来进行镇静。
