Objective: To determine risk factors and clinical consequences of critical illness polyneuropathy (CIP) evaluated by the impact on duration of mechanical ventilation, length of stay and mortality.
Design: Inception cohort study.
Setting: Intensive care unit of a tertiary hospital.
Patients: Septic patients with multiple organ dysfunction syndrome requiring mechanical ventilation and without previous history of polyneuropathy.
Interventions: Patients underwent two scheduled electrophysiologic studies (EPS): on the 10th and 21st days after the onset of mechanical ventilation.
Results: Eighty-two patients were enrolled, although nine of them were not analyzed. Forty-six of the 73 patients presented CIP on the first EPS and 4 other subjects were diagnosed with CIP on the second evaluation. The APACHE II scores of patients with and without CIP were similar on admission and on the day of the first EPS. However, days of mechanical ventilation [32.3 (21.1) versus 18.5 (5.8); p=0.002], length of ICU and hospital stay in patients discharged alive from the ICU as well as in-hospital mortality were greater in patients with CIP (42/50, 84% versus 13/23, 56.5%; p=0.01). After multivariate analysis, independent risk factors were hyperosmolality [odds ratio (OR) 4.8; 95% confidence intervals (95% CI) 1.05-24.38; p=0.046], parenteral nutrition (OR 5.11; 95% CI 1.14-22.88; p=0.02), use of neuromuscular blocking agents (OR 16.32; 95% CI 1.34-199; p=0.0008) and neurologic failure (GCS below 10) (OR 24.02; 95% CI 3.68-156.7; p<0.001), while patients with renal replacement therapy had a lower risk for CIP development (OR 0.02; 95% CI 0.05-0.15; p<0.001). By multivariate analysis, CIP (OR 7.11; 95% CI 1.54-32.75; p<0.007), age over 60 years (OR 9.07; 95% CI 2.02-40.68; p<0.002) and the worst renal SOFA (OR 2.18; 95% CI 1.27-3.74; p<0.002) were independent predictors of in-hospital mortality.
Conclusions: CIP is associated with increased duration of mechanical ventilation and in-hospital mortality. Hyperosmolality, parenteral nutrition, non-depolarizing neuromuscular blockers and neurologic failure can favor CIP development.