机械通气下外科危重症患者静息能量消耗评价

Evaluation of Resting Energy Expenditure in Critically Surgical Patients Undergoing Mechanical Ventilation

目的比较机械通气下外科危重症患者测定的静息能量消耗（MREE）与校正Harris-Benedict公式计算的静息能量消耗（CREE）之间的差异,并且评估各静息能量消耗与疾病严重程度的相关性。方法 2008年8月至2010年2月符合本研究入选标准的外科危重症患者21例,收集入选患者相关数据,计算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）。MREE采用美国MedGraphics CCM/D间接能耗测定法（IC法）测定;同时,CREE由校正Harris-Benedict公式计算得出。根据入院时APACHEⅡ评分,将患者分为2组,即≥20分组（n=8）和〈20分组（n=13）,对不同疾病严重程度患者的MREE与CREE进行比较。结果营养治疗1周内患者MREE总的变化趋势的差异无统计学意义（P=0.625）,而CREE总的变化趋势的差异有统计学意义（P〈0.001）。营养治疗1周内,患者的CREE〔（1 984.49±461.83）kcal/d〕明显高于MREE〔（1 563.88±496.93）kcal/d〕,P〈0.001,其中营养治疗后0、1、2和4 d的MREE均明显低于相应时间的CREE（P〈0.01）,而其余时间点两者的差异无统计学意义（P〉0.05）。在营养治疗1周内患者APACHEⅡ评分和MarshaⅡ评分均呈逐渐下降趋势,总的变化趋势的差异均有统计学意义（P〈0.001）。在营养治疗0-7 d,≥20分组患者的APACHEⅡ评分和MarshaⅡ评分分别高于〈20分组患者的APACHEⅡ评分和MarshaⅡ评分,差异均有统计学意义（P〈0.05或P〈0.01）;2组患者在营养治疗1周内,APACHEⅡ和MarshaⅡ评分均明显降低,其差异有统计学意义（P〈0.001）。营养治疗1周内,患者的CREE与APACHEⅡ评分（r=0.656,P〈0.001）和MarshaⅡ评分（r=0.608,P〈0.001）的变化之间呈正相关;而MREE与APACHEⅡ评分（r=-0.045,P=0.563）之间无相关性,但与MarshaⅡ评分（r=0.263,P=0.001）成正相关;MREE与CREE的变化趋势之间无相关性（r=0.064,P=0.408）。营养治疗1周内,APACHEⅡ评分≥20分组患者的MREE变化趋势的差异有统计学意义（P=0.034）,而APACHEⅡ评分〈20分组患者的MREE变化趋势差异无统计学意义（P=0.223）。营养治疗0-7 d,APACHEⅡ评分≥20分组患者的MREE与APACHEⅡ评分〈20分组患者的MREE之间比较差异无统计学意义（P〉0.05）;APACHEⅡ评分≥20分组患者总体CREE〔（1 999.55±372.73）kcal/d〕与APACHEⅡ评分〈20分组患者总体CREE〔（1918.39±375.27）kcal/d〕之间的差异亦无统计学意义（P=0.887）。APACHEⅡ评分≥20组患者除营养治疗3和5 d外,其余时间的CREE均明显高于MREE（P〈0.05）;而APACHEⅡ评分〈20组患者仅在营养治疗0-2 d的CREE显著高于MREE（P〈0.01或P〈0.05）。营养治疗0-7 d,APACHEⅡ评分≥20分组患者的MREE和CREE分别与APACHEⅡ评分〈20分组患者的MREE和CREE比较,差异均无统计学意义（P〉0.05）。结论基于病情校正的Harris-Benedict公式明显高估了外科危重症患者,特别是APACHEⅡ评分≥20分患者的静息能量消耗水平;IC法是评价静息能量消耗的标准方法。

Objective To compare the indirect calorimetry（IC） measured resting energy expenditure（MREE） with adjusted Harris-Benedict formula calculating resting energy expenditure（CREE） in the mechanically ventilated surgical critically ill patients and to evaluate the relationship between the resting energy expenditure（REE） with the severity of illness.Methods Twenty-one patients undergonging mechanical ventilation for critical illness in the intensive care unit of general surgery between August 2008 and February 2010 were included in this study.Data during the study period of nutrition support were collected for computation of the severity of critical illness by acute physiology and chronic health evaluation Ⅱ scores（APACHE Ⅱ scores） and organ dysfunction scores（Marshall scores）.MREE was measured by using IC of the MedGraphics CCM/D System within the first 7 d after nutrition therapy.CREE was calculated by using the HarrisBenedict formula adjusted with correction factors for illness at the same time.According to APACHE Ⅱ scores on admission,the enrolled patients were divided into two groups： APACHEⅡ score ≥20 scores group（n=8） and APACHE Ⅱ score 20 scores group（n=13）,and the differences between MREE and CREE of patients in two groups were determined.Results The reduction of variation tendency in CREE other than MREE in the enrolled patients within the first week of nutritional support was statistical significance（P0.001）.The CREE of patients（（1 984.49±461.83） kcal/d） was significantly higher than the MREE（（1 563.88±496.93） kcal/d） during the first week of nutritional support（P0.001）.The MREE on the 0,1,2,and 4 d after nutrition therapy were statistically significant lower than CREE at the same time interval in these patients（P0.01）,and the differences at the other time points were not significant（P0.05）.There was a trend towards a reduction in APACHE Ⅱ and Marshall scores within the first week of nutrition therapy that reached statistical significance（P0.001）.During the first week of nutrition therapy,APACHEⅡ and Marshall scores of patients in ≥20 scores group were significantly higher than those in 20 scores group,respectively（P0.05 or P0.01）,and the reductions of APACHE Ⅱ scores and Marshall scores were significant in patients of two groups（P0.001）.A significant positive correlation was found between CREE with APACHE Ⅱ scores（r=0.656,P0.001） and Marshall scores（r=0.608,P0.001） in patients within the first week after nutrition support.Although no statistically significant correlation was observed between MREE and APACHEⅡ scores（r=-0.045,P=0.563）,a significant positive correlation was observed between MREE and Marshall scores（r=0.263,P=0.001） within the first week after nutrition therapy.There was no correlation between MREE and CREE（r=0.064,P=0.408） in patients at the same time interval.The reduction of MREE of patients in ≥20 scores group other than in 20 scores group was statistically significant within the first week after nutrition therapy（P=0.034）.In addition,the MREE of patients in ≥20 scores group were not significantly different from those in 20 scores group（P0.05）,and the mean CREE was not different in two groups patients within the first week of nutritional therapy（（1 999.55±372.73） kcal/d vs.（1 918.39±375.27） kcal/d,P=0.887）.CREE was significantly higher than MREE of patients in ≥20 scores group within the first week except the 3 d and 5 d after nutrition therapy（P0.05）,while in 20 scores group CREE was significantly higher than MREE in patients only within the first 3 d after nutrition therapy（P0.05 or P0.01）.MREE and CREE of patients in ≥20 scores group were not different from those in 20 scores group,respectively（P0.05）.Conclusions The Harris-Benedict formula adjusted with correction factors for severity of illness systematically overestimates the REE,especially in patients with APACHEⅡ scores ≥20 scores on admission.Indirect calorimetry is the criterion method of choice for determining resting metabolic rate and caloric need for nutrition support in the mechanical ventilated critically ill patients.