Oronasal mask versus helmet in acute hypercapnic respiratory failure.

The choice of the interface for noninvasive ventilation (NIV) is a key factor in NIV success. We hypothesised that a new helmet specifically design to improve performance in hypercapnic patients would be clinically equivalent to a standard oronasal mask. In a multicentre, short-term, physiological, randomised trial in chronic obstructive pulmonary disease patients facing an acute hypercapnic respiratory failure episode, we compared the changes in arterial blood gases (ABGs) and tolerance score obtained using the helmet or mask, and, as secondary end-points, dyspnoea, vital signs, early NIV discontinuation and rate of intubation. 80 patients were randomly assigned to receive NIV either with the helmet (n=39) or mask (n=41), using an intensive care unit ventilator. Compared with baseline, in the first 6 h, NIV improved ABGs, dyspnoea and respiratory rate (p<0.05) in both groups. Changes in ABGs and discomfort were similar with the two groups, while dyspnoea decreased more (p<0.005) using the mask. The rate of intubation and the need for interface change during the whole period of NIV were very low and not different between groups. The new helmet may be a valid alternative to a mask in improving ABGs and achieving a good tolerance during an episode of acute hypercapnic respiratory failure.