ICU-Acquired Weakness Is Associated With Differences in Clinical Outcomes in Critically Ill Children

Abstract

Objective: ICU-acquired weakness, comprised critical illness myopathy and critical illness neuropathy, occurs in a significant proportion of critically ill adults and is associated with high morbidity and mortality. Little is known about ICU-acquired weakness among critically ill children. We investigated the incidence of ICU-acquired weakness among PICUs participating in the Virtual PICU Systems database. We also sought to identify associated risk factors for ICU-acquired weakness and evaluate the hypothesis that ICU-acquired weakness is associated with poor clinical outcomes.

Design: Retrospective cohort study.

Setting: PICU.

Measurements and main results: Virtual PICU System was queried for critical illness myopathy and critical illness neuropathy between January 2009 and November 2013. Demographic, admission, and clinical outcome variables including mechanical ventilation days, PICU length of stay, and discharge disposition were analyzed. The Pediatric Index of Mortality-2 was used to evaluate and control for illness severity and risk of mortality. Among 203,875 admissions, there were 55 cases of critical illness myopathy reported and no cases of critical illness neuropathy, resulting in an incidence of 0.02%. Mechanical ventilation days were higher among patients with ICU-acquired weakness versus those who did not develop ICU-acquired weakness (31.6 ± 28.9 vs 9.3 ± 20.6; p < 0.001). In our multivariable analysis, when controlling for Pediatric Index of Mortality-2, ICU-acquired weakness was more frequently reported in those with admission diagnoses of respiratory illness and infection and the need for mechanical ventilation, renal replacement therapy, extracorporeal life support, and tracheostomy. ICU-acquired weakness was associated with a longer PICU length of stay, episodes requiring mechanical ventilation, and discharge to an intermediate, chronic care, and rehabilitation care unit. ICU-acquired weakness was not independently associated with mortality.

Conclusions: ICU-acquired weakness is uncommonly diagnosed among PICU patients reported in Virtual PICU System. ICU-acquired weakness is associated with critical care therapies, invasive procedures, and resource utilization. Limitations of our retrospective study include underrecognition of ICU-acquired weakness and lack of standardized diagnostic criteria within Virtual PICU System. Prospective studies are needed to better understand the true incidence, risk factors, and clinical course for patients who develop ICU-acquired weakness.