The role of polyneuropathy in motor convalescence after prolonged mechanical ventilation

Objective. - To test the hypothesis that prolonged motor recovery after longterm ventilation may be due to polyneuropathy and can be foreseen at an early stage by electromyography (EMG). Design. - Cohort study with an entry period of 18 months. Polyneuropathy was identified by EMG studies in the intensive care unit (ICU). During a 1-year follow up, amount of time was recorded to reach a rehabilitation end point. Setting. - The general ICU of a community hospital. Patients. - Fifty patients younger than 75 years who were receiving mechanical ventilation for more than 7 days. Main Outcome Measures. - A rehabilitation end point was defined as return of normal muscle strength and ability to walk 50 m independently. Results. - In 29 of 50 patients, an EMG diagnosis of polyneuropathy was made in the ICU. Patients with polyneuropathy had a higher mortality in the ICU (14 vs 4; P=.03), probably related to multiple organ failure (22 vs 11; P=.08) or aminoglycoside treatment of suspected gram-negative sepsis (17 vs 4; P=.05). Rehabilitation was more prolonged in 12 patients with polyneuropathy than in 12 without polyneuropathy (P=.001). Of nine patients with delays beyond 4 weeks, eight had polyneuropathy, five of whom had persistent motor handicap after 1 year. In particular, axonal polyneuropathy with conduction slowing on EMG indicated a poor prognosis. Conclusions. - Polyneuropathy in the critically ill is related to multiple organ failure and gram-negative sepsis, is associated with higher mortality, and causes important rehabilitation problems. EMG recordings in the ICU can identify patients at risk.