Determinants of immediate failure of noninvasive mechanical ventilation outside the intensive care unit

This study aimed to characterize which are the early determinants of immediate failure of the use of noninvasive mechanical ventilation (NIMV) outside the ICU.

This prospective study included patients who were admitted to the Military Hospital in Guayaquil, Ecuador. Each variable was analyzed independently by using a multiple logistic regression model toward establishing an association with the event.

A total of 249 cases of NIMV over a 10 year period of its application outside the ICU was included in the study. Fifty-five (22.10%) patients were transferred to the ICU, A multivariate analysis showed that the determinants of immediate NIMV failure outside the ICU were the following: age (OR: 1.12; P = 0.03); SBP (OR: 1.04; P = 0.001); HR (OR: 1.66; P < 0.0001); pCO₂ (OR: 1.16; P = 0.007); pO2 (OR: 1.35; P = 0.003); levels of IPAP (OR: 1.35; P < 0.0001); and the number of quadrants affected, as shown in a chest X-ray (OR: 1.40; P < 0.0001).

The number of affected quadrants in a chest X-ray, tachyarrhythmia and hypoxemia may be useful in the initial decision in the use of NIMV outside the ICU. High values of IPAP, the persistence of elevated pCO₂, arterial hypotension, and age could be useful as a second screening associated with immediate NIMV failure outside the ICU.