The development of respiratory intermediate care units (RICUs) has allowed for better care of patients with acute respiratory failure (ARF) of diverse etiology.1 RICUs are beneficial for patients requiring noninvasive ventilation (NIV). In the case of severe asthma exacerbations (SAE), the use of NIV remains controversial.2

We read with interest the original study by Núñez et al.3 analyzing the progress of patients with SAE at an RICU. This important contribution highlights the importance of these units. However, in our opinion, there are some aspects of this study that need to be clarified.

A. In the selection of patients, the date of diagnosis, reversibility of bronchial obstruction, family history, and other features supporting diagnosis are unknown. Among SAE patients admitted to RICU, 37% were active smokers or former smokers. Furthermore, of the ten patients receiving NIV, five were obese and three had kyphoscoliosis.

This gives rise to the following questions: How many patients had asthma? How many had COPD and not asthma? NIV can be effective, even in patients with COPD and pneumonia (the most frequent finding in RICU patients). This leads us to wonder whether the patients with kyphoscoliosis and obesity had chronic hypoventilation and whether they could have benefited from NIV.

B. Regarding the definition of SAE, according to the GINA guidelines, patients with severe asthma flare-up can have a peak flow of <60% of the known or theoretical maximum value, or else <100l/min and/or PaO2<60mmHg.4 The average peak flow in RICU patients is substantially greater, so airflow limitation might not be the most influential factor in the blood-gas deterioration. The physical examination parameters suggested by the GINA guidelines – alertness, use of accessory muscles, respiratory and heart rate, etc. – have not been reported.

A description of the authors’ recommendations on the criteria for RICU admission would be interesting. Might SAE patients benefit from RICU monitoring, whether they receive NIV or not? We believe that if the previous recommendations are met, the answer is yes, and in this way prompt attention can be guaranteed, if necessary.5

In any case, this study does not allow conclusions to be drawn on the effect of NIV in patients with SAE, although we accept that this is not its purpose. Studies of NIV in SAE have been carried out in emergency departments. The use of NIV has been associated with an improvement in lung function and respiratory mechanics, but no changes have been observed in hospitalization or intubation rates. These objectives should be included in future studies, and appropriate selection criteria and methodology – mode and ventilation parameters, interface type, hours of ventilation, aerosol methodology, etc. – should be employed.2

With regard to economic aspects, we agree that RICUs are cost-effective, but, again, the methodology of this study limits conclusions.