机械通气患者静息能量消耗测定

目的探讨机械通气治疗患者能量消耗与疾病严重程度的相关性，比较间接能量消耗测定仪测定的能量消耗与Harris—Benedict公式推导的能量消耗差异。方法以24例采用机械通气治疗的普外科重症监护病房患者为研究对象，收集采用机械通气72h时的相关数据计算急性生理与既往健康状况评分Ⅱ（APACHEⅡ）和MarshaⅡ评分。机械通气72h时，采用MedGraphicsCCM／DSystem能量测定系统测定静息能耗值（MREE）；采用Harris—Benedict公式计算基础能耗值，再乘以相应应激系数得出预测静息能耗值（PREE）。结果机械通气72h时，所有患者的平均APACHEⅡ评分和MarshaⅡ评分分别为（14±5）和（6±3）分，MREE和PREE分别为（6793．64±1197．15）和（8041．02±1971．54）kJ／d。MREE与PREE间无相关性（r^2=0．28，P=0．07），差异有统计学意义（t=7．62，P=0．04）。MREE与APACHEⅡ评分（r^2=0．14，P=0．08）和MarshaⅡ评分（r^2=0．08，P=0．63）间、PREE与APACHEⅡ评分（r^2=0．05，P=0．65）和MarshaⅡ评分（r^2=0．03，P=0．87）间均无显著相关性。结论机械通气患者能量消耗与疾病严重程度无相关性。采用校正Harris—Benedict公式推导的PREE过高估计了机械通气患者的能耗水平。

Determination of energy expenditure in mechanically ventilated patients

Objective To investigate the energy expenditure of mechanically ventilated patients,compare the measured energy expenditure (MREE) with the energy expenditure expected from the Harris-Benedict equation adjusted with correction factors (PREE). Methods Twenty-four critically ill adult patients who were mechanically ventilated in the intensive care unit were enrolled in this study. Data during the 72 hours of mechanical ventilation were collected for computation of severity of illness. Resting energy expenditures were derived at 72hours after mechanical ventilation by indirect calorimetry. Predicted basal energy expenditure was obtained at the same time using the Harris-Benedict equation and predicted resting energy expenditure was calculated using the Harris-Benedict value adjusted with correction factors for illness. Results The Acute Physiology and Chronic Health Evaluation Ⅱ (APACHE Ⅱ)scores and Marshall scores were 14 ± 5 and 6 ± 3, respectively. MREE and PREE were (6 793.64 ± 1 197.15) and (8 041.02 ± 1 971.54) kJ/day, respectively. There was no correlation between MREE and PREE (r2 = 0. 28, P = 0. 07), and the difference between MREE and PREE was statistically significant (t = 7.62, P = 0.04). No statistically significant correlations were observed between both MREE or PREE and APACHE Ⅱ score or Marshall score (r2 = 0. 14, P = 0. 08; r2= 0. 08, P = 0. 63; r2 = 0. 05, P =0. 65; r2 = 0.03, P = 0. 87, respectively). Conclusions In mechanically ventilated patients, the energy expenditure is not correlated with the severity of illness. The Harris-Benedict prediction modified with correction factors for severity of illness systematically overestimates the total energy expenditure.