Relationship between intubation rate and continuous positive airway pressure therapy in the prehospital setting

Background: To determine whether the prehospital use of continuous positive airway pressure (CPAP) therapy is associated with a reduced rate of endotracheal intubation in patients with an acute respiratory disorder brought to the emergency department (ED).

Methods: We reviewed medical records of patients with acute respiratory distress who had been treated with CPAP in the Mobile Intensive Care Unit (MICU) from January 2010 to December 2011. These records were compared with those of patients who received standardized care without CPAP in the MICU from January 2004 to December 2004. Categorical variables were summarized as frequencies and compared between groups using Fisher's exact test or the Chi-square test. Continuous variables were summarized as medians (interquartile range), and comparison between the groups was made using Wilcoxon's rank-sum test. The relationship between CPAP and intubation rate was determined using multivariable logistic regression analysis of propensity scores. The results were presented as odds ratio (OR), 95% confidence interval (CI), and P value for test effect. The adequacy of the model was calibrated using Hosmer and Lemeshow's goodness-of-fit test. P<0.05 was considered statistically significant.

Results: The records of 785 patients were reviewed. Of the 215 patients treated with CPAP in the MICU, 13% were intubated after admission. In contrast, of the 570 patients who did not receive CPAP, 28% were intubated after ED admission. Unadjusted logistic regression analysis showed that patients who had been treated with CPAP were less likely to be intubated than those without CPAP treatment (OR=0.37, 95%CI, 0.24-0.57, P<0.0001). With propensity scores adjusted, multivariate logistic regression analysis showed that CPAP treatment was associated with a 62% reduction of intubation (OR=0.384, 95%CI, 0.25-0.60, P<0.0001).

Conclusions: In patients with acute respiratory disorder, there was a relationship between CPAP therapy and the decreased intubation rate. CPAP therapy was feasible in prehospital management of patients with respiratory distress.