间接能量消耗测定技术在腹部外科重症病人中的应用

Application of indirect calorimetry for energy expenditure measurement in surgical critically ill patients

目的比较外科重症病人间接测热法(indirect calorimetry,IC)与校正Harris-Benedict公式计算的能耗值之间的差异,并且评估接受机械通气的危重症病人能耗水平与疾病严重程度的相关性。方法 2015年2月至2016年10月间进入外科重症监护病房、符合本项研究入选标准的成年危重症病人共24例。24例病人在本研究开始时正在接受机械通气治疗。营养治疗期间收集入选病人急性生理与既往健康状况评分(APACHEⅡ评分)和器官功能不全评分(Marshall评分),以评价其疾病严重程度。营养治疗1周内,每日采用IC测定能耗;同时,由依据疾病严重程度而校正的HarrisBenedict公式计算能耗值,以便比较接受机械通气治疗的外科重症病人能耗测定值与计算值的差异。结果营养治疗1周内,24例病人平均能耗计算值为(8 670.88±1 828.53)k J/d[即(2 072.39±437.03)kcal/d],明显高于平均能耗测定值的(6 683.90±1 981.75)k J/d[即(1 597.49±473.65)kcal/d],两者间差异具有统计学意义(P<0.001);营养治疗当天、第1、2、4天的能耗计算值明显高于测定值,其差异具有统计学意义(P<0.05)。营养治疗1周内,入选病人的能耗计算值与测定值之间无相关性(r=0.048,P=0.565)。另外,营养治疗1周内的能耗测定值与APACHEⅡ评分之间也没有相关性(r=-0.032,P=0.602)。结论接受机械通气的外科重症病人的能耗与疾病严重程度无关;基于病情状态和严重程度而校正的Harris-Benedict公式明显高估了病人实际能耗水平;IC是评价危重症病人能耗水平的标准方法。

Objective To compare the indirect calorimetry （IC） measured energy expenditure （MEE） with adjusted Harris-Benedict formula calculating energy expenditure （CEE） in the mechani- cally ventilated surgical critically ill patients and to evaluate the relationship between the energy expenditure （EE） with the severity of illness. Methods Twenty-four adult patients receiving mechanical ventilation for critical illness in the general surgery intensive care unit between February 2015 and October 2016 were eligible for inclusion of the study. Data during the study period of nutrition support were collected for computation of the severity indices of critical illness, Acute Physiology and Chronic Health Evaluation Ⅱ （APACHE Ⅱ score） and Marshall score. EE was measured for those enrolled critically ill mechanically ventilated patients （n = 24） using IC within the first 7 days after nutrition therapy. Predicted EE was obtained at the same time for each patient using the Harris-Benedict equ tion calculated from the value adjusted with correction factors for illness to determine the discrepancy between MEE and CEE. Results In a group of 24 acutely ill surgical patients, the mean predicted metabolic requirements based on Harris-Benedict equation with the addition of stress factors （8670. 88 ± 1828. 53） kJ/day [-（2072. 39 ± 437. 03） kcal/day] were greater than the mean metabolic expendi- tures measured by IC （6683. 90 ± 1981.75） kJ/day [-（1597. 49 ± 473.65） kcal/day], P〈0. 001. Dur-ing the first week of nutritional support, the differences between MEE and CEE in these patients were statistically significant on admission and 1, 2, 4 days after nutrition therapy （P〈0. 05）. There was little correlation between MEE and CEE （r = 0. 048, P = 0. 565）. Moreover, no statistically significant correlation was observed between MEE and APACHEII scores （r= - 0. 032, P = 0. 602）. Conclusions In mechanically ventilated patients, the EE is not correlated with the severity of illness. The Harris- Benedict prediction modified with correction factors for severity of illness systematically overestimates the EE. IC is the criterion method of choice for determining EE for nutrition support in critically ill patients receiving mechanical ventilation.