CPAP holiday: are we there yet?

Population pharmacokinetics of rifampicin, pyrazinamide and isoniazid in children with tuberculosis: in silico evaluation of currently recommended doses. We appreciated the article by ROSSI et al. [1] entitled " Is continuous positive airway pressure necessarily an everyday therapy in patients with obstructive sleep apnoea? " , as well as the corresponding editorial [2], recently published in the European Respiratory Journal. Indeed, there are limited data on the evolution of obstructive sleep apnoea (OSA) during continuous positive airway pressure (CPAP) therapy and whether this treatment is required on a daily basis. Although as ROSSI et al. [1] freely admitted, their study was not without flaws, we feel that some issues should be further addressed and discussed. The use of pulse oximetry to diagnose sleep apnoea is not recommended [3], as it may underestimate the degree of the disease, which was exactly what was being studied in this case. In addition, it is possible that the increase in the Epworth Sleepiness Scale score observed in group 2 patients independently of OSA recurrence might be explained by respiratory events and sleep arousals not diagnosed by that examination. Thus, this stands as an important limitation. As from the 125 patients enrolled in the study, only nine (7%) patients did not have OSA recurrence after 2 weeks (in 89 patients, it recurred within 4 days and those patients were not further evaluated), we think that the overall conclusions are excessively optimistic. Additionally, we would like to inquire whether the patients who stopped CPAP treatment and did not have a return of OSA even after 2 weeks (n=9) had a greater reduction in weight since the beginning of treatment than other patients. No reference to this possible variation is made in the article and we feel this is highly relevant. Concerning the CPAP treatment, we wonder if the pressure used in those patients was significantly lower than in those in whom OSA returned. As there are no clear recommendations in clinical practice regarding for how long CPAP should be suspended before evaluating OSA persistence in order to stop the therapy, as for example, after a significant loss of weight, we feel that this study could be of guidance. It allows us to admit that it could be prudent only to perform the sleep evaluation 2 weeks after withdrawing CPAP, as 55% of patients that did not have OSA recurrence after 4 days had more than 10 …