Risk factors for the development of polyneuropathy and myopathy in critically ill patients

Previously, mainly retrospective and a few important prospective studies postulated the role of sepsis or systemic inflammatory response syndrome (SIRS), multiple organ failure, and the use of medication as causative factors for the development of critical illness polyneuropathy and myopathy (CIPNM). This study aimed to identify the risk factors in the development of CIPNM.

Prospectively, we studied 98 patients who were on artificial respirators for the development of CIPNM. The Acute Physiology and Chronic Health Evaluation (APACHE) III score, presence of SIRS, and sepsis severity score at entry; the dosage of midazolam, vecuronium, and steroids at entry and day 7 of artificial respiration; and the use of aminoglycosides at entry were related with time to CIPNM or time of last follow-up. The Kaplan-Meier method and log-rank test were used.

Thirty-two patients (33%) developed CIPNM. After multivariate analysis, it was found that the APACHE III score and the presence of SIRS were significantly related with risk for the development of CIPNM. No significant relation was found for the use of midazolam, vecuronium, or steroids. Based on a risk index from a Cox regression model with APACHE III score and presence of SIRS as outcomes, three groups could be constructed with low-, medium-, and high-risk patients for the development of CIPNM.

The APACHE III score, a quantitative index of disease severity based on clinical and laboratory physiologic data, is a valuable predictor for the development of CIPNM in patients in the intensive care unit. Together with the presence of SIRS, it can be used to estimate the risk of developing CIPNM for patients on artificial respirators.