The Magnitude and Time Course of Muscle Cross-section Decrease in Intensive Care Unit Patients

Objective Bedriddenness and immobilization of patients at an intensive care unit may result in muscle atrophy and devaluation in quality of life. The exact effect of immobilization on intensive care unit patients is not known. The aim of this study was to investigate the magnitude and time course of muscle cross-section decrease in acute critically ill patients admitted to the intensive care unit.

Design An observational pilot study was performed in intensive care unit patients. Data of bilateral ultrasound muscle cross-section measurements of the knee extensors and the elbow flexors were collected. Thirty-four intensive care unit patients were included in this study; data are presented from 14 patients who were measured at least three times.

Results Repeated measures analysis of variance shows a significant decrease in muscle cross-section over time (F-1,F-13 = 80.40, P 0.001).The decrease in muscle cross-section of the arms was significantly higher (F-1,F-13 = 5.38, P = 0.037) than the decrease of the legs. Four weeks after intensive care unit admission, the muscle cross-section decrease had not reached an asymptote yet.

Conclusions The muscle cross-section decrease in bedridden intensive care unit patients is significant for a time of 2 to 4 weeks. The decrease in muscle cross-section of the arms is greater than the decrease of the legs.