Measurement And Significance Of Resting Energy Expenditure In Critically Ill Children

The interaction between nutritional status and major diseases is becoming more and more obvious,the impact of nutritional treatment strategies on clinical outcomes is a hot field of ongoing research,and nutritional support treatment of critically ill children has also attracted more and more attention.Severe children may already be malnourished when they are admitted to hospital,coupled with various obstacles caused by disease,unable to provide optimal nutrition,and an increased risk of secondary nutritional deterioration,resulting in worsening clinical outcomes.Studies have shown that malnutrition affects 50%of hospitalized children and 25%～70%of critically ill children,increasing the incidence of complications and mortality to some extent^[1].Resting energy expenditure（REE）refers to the energy consumption of the body after fasting for more than 2 hours and lying down for 30 minutes at an appropriate temperature,accounting for about 70%～80%of the total energy,reflecting the energy consumption needed to maintain the normal basic physiological function of the human body in a quiet state.There are great differences in energy requirements among different ages,different disease states and different individuals.Studies have shown that metabolic responses in critically ill children are characterized by resting energy consumption and increased metabolism.Compared with adults,children have lower muscle mass and fat percentage,poor tolerance to fasting,easy to consume protein,and significantly increased risk of malnutrition when suffering from serious illness^[2].The prevalence rate of malnutrition can reach more than 47%^[3].However,Larsen^[4]found that 53.3%of critically ill children in PICU were overfed.Therefore,accurate monitoring of resting energy consumption is a strong guarantee to achieve individual nutritional support for critically ill children,which can avoid underfeeding and overfeeding.In clinical practice,predictive equations are usually used to evaluate energy consumption,but most of the predictive formulas are based on healthy children,and the accuracy in critically ill children is uncertain^[5,6].Indirect calorimetry（IC）is considered to be a safe,non-invasive and relatively accurate method with high repeatability and can be used in both respiratory support and non-respiratory support patients with fewer complications.It is a method strongly recommended by the 2018 European Society for Parenteral and Enteral Nutrition（ESPEN）guidelines for monitoring resting energy consumption in critically ill patients^[7].It is helpful to guide the formulation of the best nutrition program^[8].However,as a new clinical tool for measuring energy metabolism,nutrition metabolism vehicle（indirect calorimeter）has not been widely used in pediatrics in China because of its high cost and strong professionalism.The purpose of this study was to determine the REE of critically ill children of different ages and different types of diseases by IC,to understand the characteristics of resting energy consumption of critically ill children and the changes of energy metabolism within one week after admission,in order to provide the best nutritional treatment and improve the clinical outcome.Objective1.To explore the characteristics of resting energy metabolism in critically ill children of different ages under different disease conditions.2.To explore the changes of energy metabolism in children with severe infection of different ages within one week after admission.Materials and methodsThe clinical data of 134 critically ill children hospitalized in PICU,the third affiliated Hospital of Zhengzhou University from October 2019 to October 2020 were collected.The patients were divided into three groups according to age:<3 years old group,3-9 years old group and 10-14 years old group;according to etiology,they were divided into infection group and non-infection group.The REE of all the children were measured by IC using the American MEDGRAPHIC metabolism car,postoperative children with congenital heart disease and intestinal colostomy were measured once within 24 hours after surgery,and the other children completed the first measurement within 24 hours after admission.REE was measured in 48 infected children on the 1,3,5 and 7 day of admission,respectively.At the same time,the predictive resting energy expenditure（PREE）of all children was calculated by Schofield-HTWT formula.Criteria for determining the state of energy metabolism:REE/PREE<90%is low metabolism;90%～110%is normal metabolism;>110%is high metabolism.SPSS 26.0 statistical software was used for data processing.Results1.The measured value of REE in<3 years group was significantly higher than that of PREE,while that in 3-9 years group and 10-14 years group were significantly lower than that of PREE（P<0.05）.2.There were significant differences in the distribution of metabolic state（REE/PREE）among different age groups（P<0.05）.With the increase of age,the metabolic state decreased gradually.3.REE and REE/PREE in<3 years old infection group were significantly higher than those in non-infection group（P<0.05）.REE in 3-9 years old infected group was significantly higher than that in non-infected group,but there was no significant difference in REE/PREE（P>0.05）.There was no significant difference in REE and REE/PREE between 10-14 years old infected group and non-infected group（P>0.05）.4.The changes of REE and REE/PREE in infected children<3 years old day 1,3,5,7 after admission were statistically significant（P<0.05）.There was no significant change in REE and REE/PREE in infected children 3-9 years and 10-14years on day 1,3,5,7 after admission（P>0.05）.ConclusionsThe characteristics of energy metabolism in critically ill children are related to age and disease.Infants and young children,especially those complicated with infection,mainly have high metabolism.It is suggested that IC should be used to monitor the REE of critically ill children to guide clinical nutritional support treatment.