The role of polyneuropathy in motor convalescence after prolonged mechanical ventilation.

OBJECTIVE: To test the hypothesis that prolonged motor recovery after long-term 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.