Study About Measurement Of Resting Energy Expenditure In Surgical Critically Ill Patients

Objective: To compare the differences between the measured resting energy expenditure(REE) calculated by the indirect calorimetry(IC) with the REE calculated by the Harris-Benedict formula(H-B formula) and weight formula(PREE) in the mechanically ventilated surgical critically ill patients. To compare the differences in the measured resting energy expenditure calculated by the indirect calorimetry(MREE) in the patients with different severity. Discussing the influencing factors of REE and the differences in REE in surgical critically ill patients. Methods: The research object are the patients with mechanically ventilated in SICU, XuanWu hospital, from April 2014 to April 2015, requiring the age ≥18 years old, mechanical ventilation time ≥3 days, nutritional support ≥ 5 days. We measured the MREE in the first day, the third day and the fifth day. Comparing the result with the PREE, and discussing the difference in REE calculated from different methods. According to the Acute Physiology and Chronic Health Evaluation(APACHE II) and the Sequential Organ Failure Assessment(SOFA) divided the patients with APACHE II ≤ 15 and APACHE II>15, SOFA≤ 5 and SOFA>5. Analyzing the difference between the two groups respectively. Analyzing the metabolism distribution range by each patients, MREE. Analyzing the relevance between the MREE with the factors such as age, weight, APACHE II score and SOFA score. Results: There are twenty-nine patients fit into our research,thirteen males and sixteen females, average age is 65.89±16.89 years old. The average age in male is 66.68±16.89 years old, in female is 65.31±17.57 years old. Measuring the MREE 188 times in total, 80 times in male and 108 times in female, recording the APACHE II score and the SOFA score. There is a significance difference between the MREE with PREE(H-B formula and weight formula) on the first day, the third day and the fifth day. There is a significant difference(P<0.05) between the result from the IC with the H-B formula on the first day, the third day and the fifth day. The result calculated from H-B formula is higher than the result calculated from IC. There is a significant difference(P<0.05) between the result from the IC with the weight formula on the first day, the third day and the fifth day. The result calculated from the weight formula is lower than the result calculated from IC. The research shows no significance difference(t=0.649,p=0.517) in MREE in APACHE II ≤ 15 group and APACHE II > 15 group, but it shows a significance difference(t=2.898,p=0.004) in MREE in SOFA≤ 5 group and SOFA>5 group. The result shows that 6.4% patients in high metabolic status, 31.4% patients in normal metabolic status, 66.2% patients in low metabolic status. The result also shows there is an obvious relativity between MREE with weight, age, and the SOFA score, but there is no obvious relativity between MREE with the APACHE II score. There is a negative correlation(P<0.05) between the MREE with the age and the SOFA score with its correlation index(r=-0.383,r=-0.171).There is a positive correlation(P<0.05) between the MREE with the weight with its correlation index(r=0.502).There is no significance relativity(P>0.05) between the MREE with the APACHE II score. Conclusion: The surgical critically ill patients, REE is quite different because of its condition, individual factors and some other factors. Different patients have different metabolism level, and the metabolism level is different in the patient who is in different disease progression. Since the weight formula and the H-B formula can not consider all the factors in, so the result is different between the PREE and the MREE in different times. Since IC is the most accurate method, clinical nutrition support should rely on its result. There is no relevant between the MREE with the APACHE II score, but a relevant between the MREE with the SOFA score performed the MREE is high in the low SOFA score patients. So the clinical nutrition support should consider each patient,s organ function, avoiding aggravating organ function damage by over nutrition support. The result reveals the surgical critically ill patients are not in high metabolic level as the major considered generally. With patients in stable condition, the use of sedative drugs and the use of respirator to reduce the work of respiratory muscle, the patient,s metabolic level can maintain in a low metabolic level. So the clinical nutrition support should forbid overfeeding. There is an obvious relativity between MREE with weight, age, and the SOFA score. There is a negative correlation between the MREE with the age and the SOFA score. There is a positive correlation between the MREE with the weight. The use of the indirect calorimetry have a great effect on accurate energy supply for surgical critically ill patients, if the situation allowed we should use it universally. It can improve surgical critically ill patients, malnutrition. And it has a great significance on disease outcome and patients, healthy.