A Preliminary Study On The Comparison Of Indirectcalorimetry And Formula Prediction To Guide ICU Patient Nutrition Support

Objective:To investigate whether the repeated use of indirect calorimetric measurements of REE to guide critical patient nutritional support can improve their survival outcome compared to a single,weight-based ACCP prediction formula.Methods:This is a prospective,randomized,single-center clinical trial study conducted in a general adult intensive care unit(ICU).The trial collected 37 critically ill patients who were admitted to the Emergency Department of Critical Care Medicine(EICU)at the Second Affiliated Hospital of Kunming Medical University from July 2017 to February 2018.All of them weremechanically ventilated patients who stay in the ICU for more than 3 days.Subjects were randomly divided into two groups.One group(study group,n = 20)was given enteral nutrition according to the resting energy expenditure(REE)measured by repeated indirect calorimetry.The other group(control group,n = 17)was given enteral nutrition according to the ACCP equation method,which is a prediction of 25 kcal/kg/day.When enteral nutrition fails to reach the target amount,parenteral nutrition is used to meet energy requirements,and intravenous pump insulin is used to maintain blood glucose below 10 mmol/L.The patient's albumin is monitored daily,and if the index is low,human albumin supplementation is given.The basic information of the two groups of patients was recorded,nutritional risk assessment,room SOFA score,APACHE II score,energy prediction value,and actual intestinal enteral energy supply.Results:The main result of this pilot study is whether the REEs that are repeatedly measured by indirect calorimetry can guide critical patient nutritional support(EN+PN)to improve their outcome compared to a single,weight-based ACCP energy prediction formula.Comparing the results of the two groups,the duration of mechanical ventilation was not significantly different between the two groups(study group,8.9±7.9 days,control group,9.8±6.1 days,p=0.701);the ICU hospitalization time was also not statistically difference(12.0 ± 9.2 days for the study group and 13.9± 6.6 days for the control group,p =0.462).There was a statistically significant trend in total hospital days(21.0±9.7 days in the study group and 29.7±17.3 days in the control group,p = 0.062).The ICU mortality was not statistically significant(5/20(25%)in the study group and 5/17(29.4%)in the control group,p=0.763);In addition,the intragroup comparisons of the energy predicted by the indirect calorimetry method and the formula method in the experimental group(IC method 1669±114kcal,formula method 14301±184kcal,p=0.000)have obvious statistical differences.Conclusion:This prospective,randomized,single-center controlled trial showed a statistically significant difference between the indirect calorimetric prediction and the calculated ACCP formula(25 kcal/kg/day).However,compared with the ACCPprediction formula commonly used in clinical practice,the use of indirect calorimetry to repeatedly measure resting energy to achieve the target energy to guide and interfere with nutritional support(EN+PN)does not reduce the duration of mechanical ventilation,ICU stay and ICU mortality in critically ill patients.