Risk factors for unplanned extubation in critically ill patients

Introduction

Unplanned extubation (UE) is a frequent complication in ICU patients associated with increased morbidity, mortality, duration of mechanical ventilation, ICU stay and hospital stay. Although UE has been studied, still not much is known on the incidence, determinants and outcome. The aim of the study was to assess the incidence and determinants of UE in a tertiary-care ICU.

Methods

From 1 December 2005 to 1 June 2008 a prospective case–control study was undertaken. Cases were consecutive adult patients in a 29-bed medical, surgical, neurosurgical, and thoracic-surgical ICU who experienced an UE. The UE was defined as premature removal of the tube by the patient. For each case, four controls were randomly selected. Controls were mechanical ventilated patients who did not experience an UE at the time a case occurred. Demographics and clinical characteristics were obtained from the electronic medical records. Wilcoxon rank-sum and chi-squared tests were used as appropriate. To determine independent risk factors for UE, univariate logistic regression was used. Determinants significant in the univariate analysis were included in the multivariate logistic regression. This model was tested for the clinically relevant interaction between determinants.

Results

In the study period, 74 UEs occurred and 296 controls were collected. The incidence of UE is 2.1% for mechanically ventilated patients and 0.4% per ventilation day. Cases and controls did not differ significantly with respect to age, type of admittance or diagnosis category. Forty-seven percent of the cases had to be reintubated, 77% did not experience another complication. Cases had significantly lower median length of intubation (5 vs. 7 days, P = 0.069), ICU mortality (18 vs. 27%, P = 0.096) and hospital mortality (19 vs. 34%, P = 0.028). Significant predictors of UE in the multivariate analysis were admittance to the thoracic surgery unit (OR = 2.63, 95% CI = 1.06 to 6.53, P = 0.037) and a Ramsay sedation score of 1 (OR = 30.57, 95% CI = 3.18 to 294.2, P = 0.003), 2 (OR = 25.47, 95% CI = 3.00 to 217.0, P = 0.003), and 3 (OR = 7.02, 95% CI = 0.78 to 63.01, P = 0.082) compared with the most sedated score. Protective factors are female gender (OR = 0.55, 95% CI = 0.26 to 1.19, P = 0.131), and use of midazolam at the time of UE (OR = 0.44, 95% CI = 0.19 to 0.99, P = 0.048).

Conclusion

Although UE can be defined as a complication we could not find a correlation with morbidity and mortality.