Myopathy following mechanical ventilation for acute severe asthma: the role of muscle relaxants and corticosteroids.
BACKGROUND
Acute myopathy following mechanical ventilation for near-fatal asthma (NFA) has been described recently, and some researchers have suggested that this complication is related to the use of neuromuscular blocking agents (NMBAs) and corticosteroids (CSs).


OBJECTIVE
To determine the incidence of acute myopathy in a group of patients and to examine the most important predictors of its development.


METHODS
A retrospective cohort study over a 10-year period (1985 to 1995) of all asthma patients who received mechanical ventilation at two centers in Vancouver (designated center 1 and center 2).


RESULTS
In center 1, there were 58 patients who had 64 episodes of NFA, and in center 2, there were 28 patients who had 30 episodes. NMBAs were used in 30 of 86 admissions for acute severe asthma (35%). The mean (+/- SD) duration of muscle paralysis was 3.1+/-2.3 days. A total of 9 patients (10.4%) developed significant myopathy. The incidence of myopathy was 9 of 30 (30%) among patients who received NMBAs. In a multiple logistic regression model, the development of myopathy was only significantly associated with the duration of muscle relaxation. The odds ratio for the development of myopathy increased by 2.1 (95% confidence interval, 1.4 to 3.2) with each additional day of muscle relaxation. The dose and the type of the CS were not significantly associated with the myopathy in the multiple logistic regression analysis.


CONCLUSIONS
Our study showed that there is a high incidence of acute myopathy when NMBAs are used for NFA. The incidence of myopathy increases with each additional day of muscle relaxation.
Behbehani
N A
NA
Department of Medicine, Vancouver Hospital and Health Sciences Centre, Canada. nasser_beh@hsc.kuniv.edu.kw
Al-Mane
F
F
D'yachkova
Y
Y
Paré
P
P
FitzGerald
J M
JM
D018806:APACHE; D000208:Acute Disease; D000328:Adult; D001249:Asthma / Q000628:therapy*; D004576:Electromyography; D005260:Female; D005500:Follow-Up Studies; D005938:Glucocorticoids / Q000009:adverse effects*; D006801:Humans; D006854:Hydrocortisone / Q000009:adverse effects; D015994:Incidence; D008297:Male; D008775:Methylprednisolone / Q000009:adverse effects; D008875:Middle Aged; D009466:Neuromuscular Blocking Agents / Q000009:adverse effects*; D009468:Neuromuscular Diseases / Q000139:chemically induced* / Q000175:diagnosis / Q000453:epidemiology; D016017:Odds Ratio; D010197:Pancuronium / Q000009:adverse effects; D012121:Respiration, Artificial / Q000379:methods*; D012189:Retrospective Studies
D005938:Glucocorticoids; D009466:Neuromuscular Blocking Agents; D010197:Pancuronium; D006854:Hydrocortisone; D008775:Methylprednisolone