机械通气患儿能量代谢特点和喂养状态研究

目的：通过间接测热法测定机械通气患儿静息能量消耗,研究其能量代谢特点和喂养状态,为改进营养支持策略提供依据。方法以2013年2月至2013年11月入住PICU,符合间接测热条件的37例机械通气患儿为研究对象,自符合测定条件起第1、4、7、10、14和21天测定静息能量消耗( measurement of resting energy expenditure,MREE),运用Schofield-HTWT公式计算预测静息能量消耗值( predicted resting energy expenditure,PREE),并统计每日热量摄入值。按MREE/PREE比值评定代谢状态：低代谢(<90％)、正常代谢(90％~110％)和高代谢(>110％)。按热量摄入值/MREE 比值评定喂养状态：喂养不足(<90％)、喂养适当(90％~110％)和喂养过度(>110％)。结果37例危重症儿童机械通气第1天,15例(40.5％)为低代谢,9例(24.3％)为正常代谢,13例(35.1％)为高代谢；机械通气第7天,呈高代谢状态患儿比例增加至46.7％,但较第1天无统计学差异(χ2＝0.516,P＝0.972)。营养支持应用率为81.1％；实施营养支持者,累计实施间接测热82次,每日热量摄入值为(33.4±22.2)kcal/(kg?d),显著低于MREE水平[(53.7±17.4)kcal/(kg?d)](t＝6.505,P<0.01)。在实施营养支持过程中,机械通气患儿有62 d(75.6％)喂养不足,8 d(9.8％)喂养适当,12 d(14.6％)喂养过度。结论 PICU滞留期间机械通气患儿能量代谢状态不断变化,且PICU滞留期间有近90％的时间里患儿喂养不达标。

Energy expenditure and nutritional practices in mechanically ventilated children

Objective To identify metabolism and feeding patterns by measurement of resting ener-gy expenditure(MREE) in mechanically ventilated children,and examine the metabolic response in relation to clinical characteristics. Methods Thirty-seven children who fulfilled the criteria for indirect calorimetry were enrolled in this prospective observational study. MREE were obtained on days 1,4,7,10,14,21,respec-tively. Patients were classified as hypometabolic,normal metabolic,and hypermetabolic when MREE were <90%,90% ~110%,and >110% of the predicted resting energy expenditure calculated by Schofield-HTWT equation,respectively. Actual energy intake was recorded, energy intake was classified as underfeeding ( <90% of MREE),adequate feeding(90% ~110%),or overfeeding( >110%). Results On the first day of mechanical ventilation,40. 5% of all children were hypometabolic,24. 3% normal metabolic,and 35. 1% hy-permetabolic. Only after 7 days, the hypermetabolic pattern dominated ( 46. 7%) . Eighty-two measurements were performed in 30 patients(81. 1%),who received nutrition support. The mean energy intake was(33. 4 ± 22. 2) kcal/(kg?d). This was significantly lower than mean MREE,which was(53. 7 ± 17. 4) kcal/(kg?d) (P<0. 01). Underfeeding,adequate feeding,and overfeeding occurred on 75. 6%,9. 8%,and 14. 6%,re-spectively. Conclusion The energy metabolism varies widely in mechanically ventilated children during hos-pitalization. Nearly 90% of the duration in PICU are underfeeding or overfeeding.