Table 4.

Multivariate analysis of factors associated with helmet CPAP failure

Factora	P value	Odds ratio [95% C.I.]
C-reactive protein, mg/L	0.001	1.006 [1.003–1.010]
Hospital admission to oxygen therapy failure, days	0.001	0.775 [0.661–0.908]
Age, years	0.002	1.054 [1.020–1.089]
PaO2/FiO2 ratio (helmet CPAP), mmHg	0.003	0.995 [0.991–0.998]
Comorbidities, n	0.005	1.582 [1.147–2.182]

CPAP: continuous positive airway pressure

^afactors entered in the backward regression model and removed due to lack of statistical significance (P > 0.05): sex, body temperature, PaO₂/FiO₂ ratio and PaCO₂ during standard oxygen treatment, PaCO₂ measured during CPAP. C-reactive protein, time to oxygen mask failure, age, PaO₂/FiO₂ ratio collected during helmet CPAP treatment and number of comorbidities were independently associated with helmet CPAP failure.