Critical illness polyneuropathy: risk factors and clinical consequences. Acohort study in septic patients

Objective: To determine risk factors and clinical consequences of critical illness polyneuropathy (CIP) evaluated by the impact on duration of mechani cal 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 requirin g mechanical ventilation and without previous history of polyneuropathy Interventions: Patients under-went 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 APACH E 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 pa tients 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 % Cl 1.34-199; p = 0.0008) and neurologic failure (GCS below 10) (OR 24.02; 95 % Cl 3.68-156.7; p < 0.001 ). while patients with renal replacement therapy had a lower risk for CIP d evelopment (OR 0.02; 95 % CI 0.05-0.15; p < 0.001). By multivariate analysi s, 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 ventil ation and in-hospital mortality. Hyperosmolality, parenteral nutrition. non -depolarizing neuromuscular blockers and neurologic failure can favor CIP d evelopment.