From the authors

We welcome the interest of P. Wijkstra in our paper 1. We agree that the choice of an effective interface for noninvasive ventilation (NIV) is integral to the success of this therapy and would welcome future research in the area. We acknowledge that our study was not without methodological weaknesses, a number of which we mention in the discussion of our paper 1. Whilst we would now consider a trial in naive patients, this was not the situation at the commencement of data collection for our study. At that time the safety and efficacy of the full face mask (FFM) for NIV during sleep was largely unknown. Our adverse experience with this interface led us to be cautious with regard to its efficacy during sleep, especially in subjects with neuromuscular disease. Indeed, this concern was borne out in the study with the observation of upper airway obstruction in one subject on FFM versus an absence of respiratory events on the nasal mask. We would still recommend careful attention to the degree of upper airway closure during sleep in subjects using a FFM.

It was with these considerations in mind that rather than choosing naïve subjects we chose a group of subjects who were receiving effective NIV therapy via a nasal mask (NM). In this sense we were well aware that the NM versus FFM comparison may be weighted toward the NM. Alternatively, the acute application of a more effective interface may be argued to have biased our study toward the FFM. The proposals of P. Wijkstra in regard to the mask acclimatisation are well thought out and in line with many of our own clinical observations. We concur with P. Wijkstra that our study did not directly address the question of the difference in pressure requirements on the FFM. Our aim would have been more appropriately worded: To determine if the pressures titrated during NM ventilation were effective during FFM ventilation. We believe our study does show that the pressure settings titrated whilst wearing the NM will be adequate if the patient is changed to a FFM.

We would hope that the results of our study will be interpreted in light of the subjects studied and the methodology used. We would direct readers to the broader conclusions of our study that full face masks appeared to be as effective as nasal masks for the delivery of noninvasive ventilation.