We read with much interest the article entitled Characteristics of prolonged non-invasive ventilation in hospital emergency departments and impact upon effectiveness. Analysis of the VNICat registry by Arranz et al.1. The first thing we wish to do is congratulate the authors for their interesting work. Also, there are some ideas we’d like to contribute to it as well.

Authors say that specific ventilators were used for non-invasive ventilation. Also, that the variables associated with the mode of ventilation were support pressure (SP), positive end-expiratory pressure (PEEP), continuous positive airway pressure (CPAP), and the value of pressure titration. We think if would have been desirable that all the different modes of ventilation used would have been collected (different hospital resources are listed in the limitations section). However, the variables collected suggest that the mode of ventilation used was SP on PEEP. However, in the result table the term EPAP appears close to the term CPAC. This could make us think that the mode of ventilation used was two pressure levels (BiPAP) and here programming is different. We know that the ventilation support the patient receives is the value of SP, but programming is different, which could lead to unsought misunderstandings when planning ventilation support.2

When results are shown on table 1, both the mean and the standard deviation of 2 different values (EPAP or CPAP) are shown. However, these have a different mechanical meaning. EPAP acts on a certain moment of the ventilation cycle to avoid physiological alveolar collapse and, therefore, recruit alveoli and improve oxygenation. On the other hand, CPAP acts constantly on the airway throughout the entire ventilation cycle of the patient. That is why we think these 2 values should have appeared separately on the table results.3

The definition of success as weaning from ventilation support (non-invasive ventilation) at the hospital emergency unit (HEU) should make us think. In some patients with acute pulmonary edema, weaning from ventilation support in the form of CPAP at the HEU could be considered a success. However, this is not eligible for patients with chronic obstructive pulmonary disease (COPD), especially if this is associated with respiratory acidosis which, in most cases, requires > 12 h of ventilation support. Here success is defined by continuity between the HEU and the patient’s next destination. Therefore, we believe that the percentage of patients admitted with ventilation support is a piece of information that should have been collected, never understood as failure but as a treatment continuity.4

Diabetes mellitus is quoted by the authors as a risk factor for prolonged non-invasive ventilation at the ER. It would have been interesting to collect variables objectively associated with prolonged ventilation support and technique failure like the oxygenation index (PaO2/FiO2 ratio), the HACOR index, the pH value, respiratory rate, poor secretion control or interphase rejection.5

We should mention here the authors’ contribution on the need for continuous medical education for healthcare professionals who work at HEUs, availability of resources, and the active participation of ER doctors in multidisciplinary projects like intermediate respiratory care units and «open» or extended intensive care units.6