[Effects of intermittent feeding and continuous feeding on muscle atrophy and nutritional status in critically ill patients].

Objective: To compare the effects of intermittent feeding and continuous feeding on muscle atrophy, nutritional status and nutritional intolerance of critically ill patients, and to provide a reference for critically ill patients to select more suitable nutritional support in clinic.

Methods: An observational study was conducted. The clinical data of 59 critically ill patients who received enteral nutrition admitted to anesthesia intensive care unit (ICU) of the Second Affiliated Hospital of Air Force Military Medical University of the Chinese People's Liberation Army from January 2019 to December 2020 were analyzed. According to different feeding methods, the patients were divided into intermittent feeding group (n = 32, 200-250 mL nutrient solution was pumped each time, 4-5 times a day, 5-6 hours interval each time) and continuous feeding group (n = 27, nutrient solution was pumped continuously and evenly). The changes of related indexes before and 7 days after enteral nutrition in ICU were recorded, including rectus femoris thickness and cross-sectional area, nutritional status related indexes [hemoglobin (Hb), albumin (ALB), prealbumin (PA) and blood glucose], incidence of aspiration, diarrhea, constipation, vomiting, abnormal gastric residue volume (gastric residue volume > 250 mL), other nutritional intolerance and the length of ICU stay.

Results: After nutritional support for 7 days, the thickness and cross-sectional area of rectus femoris decreased in both groups, indicating muscle atrophy occurred in both groups, and there was no significant difference in change value of thickness or cross-sectional area of rectus femoris between intermittent feeding group and continuous feeding group [the change value of rectus femoris thickness (cm): -0.06±0.04 vs. -0.07±0.03, the change value of rectus femoris cross-sectional area (cm): -0.71±0.23 vs. -0.81±0.24, both P > 0.05]. There were no significant differences in nutritional status related indicators after nutritional support for 7 days between intermittent feeding group and continuous feeding group [Hb (g/L): 102.2±10.9 vs. 103.2±11.3, ALB (g/L): 34.1±3.6 vs. 32.9±4.0, PA (mg/L): 209.8±10.6 vs. 205.9±13.7, blood glucose (mmol/L): 6.34±1.91 vs. 6.93±3.54, all P > 0.05]. The patients in both groups had intestinal nutrition intolerance such as aspiration, diarrhea, constipation and vomiting. However, the incidence of abnormal gastric residual volume in intermittent feeding group was significantly lower than that in continuous feeding group [9.4% (3/32) vs. 33.3% (9/27), P < 0.05]. There was no significant difference in the length of ICU stay between intermittent feeding group and continuous feeding group (days: 21.03±11.51 vs. 21.41±9.74, P > 0.05).

Conclusions: Compared with continuous feeding, intermittent feeding does not improve the muscle atrophy and nutritional status of critically ill patients, but reduce the symptoms of enteral nutrition intolerance caused by abnormal increase of gastric residual volume. It is an easy-to-implement, safe and feasible feeding method.