Helmet noninvasive mechanical ventilation in patients with acute postoperative respiratory failure.

BACKGROUND: The physiological and clinical effects of noninvasive ventilation (NIV) on acute postoperative respiratory failure are relatively unknown. The aim of this study was to determine the prediction factors for failure in the use of NIV with a helmet in this context.

METHODS: This was a prospective observational study. The use of NIV was assessed for a period of 2 years in a postoperative ICU. Demographic data were collected, as well as acute respiratory failure (ARF) and arterial gas readings. Hemodynamic changes were assessed using pulse contour cardiac output technology, and the clinical development of subjects was recorded. All subjects who developed ARF were treated using NIV as their primary care, depending on whether the technique was successful or the subject required intubation. The risk factors that determined failure in the application of NIV were subsequently determined.

RESULTS: Of the 99 subjects presenting with postoperative ARF treated with NIV using a helmet, 74 did not require intubation (74.7%). Following a multivariate analysis using logistic regression, we determined that there are 3 independent risk factors for the failure of NIV. Three factors were associated with respiratory failure: ARDS, pneumonia, and lack of improvement with NIV in 1 hour (increase in the P(aO(2))/F(IO(2))).

CONCLUSIONS: NIV using a helmet could provide an effective alternative to conventional ventilation in selected patients with postoperative ARF.