Letters to the Editor

DANGEROUS HYPOXAEMIA DURING CONTINUOUS POSITIVE AIRWAY PRESSURE TREATMENT OF OBSTRUCTIVE SLEEP APNOEA

The optimal mode of positive airway pressure for patients with obesity hypoventilation syndrome (OHS) has been the topic of some debate since the 1980s. People with OHS constitute a significant proportion of patients enrolled in home ventilation programs using bilevel (BPAP) therapy, even though continuous positive airway pressure (CPAP) corrects sleep-disordered breathing and improves awake gas exchange in many of those with concomitant OSA. The modes of BPAP ventilation available to clinicians have grown in recent years, while evidence around who will benefit from them and under what circumstances remains limited. Studies evaluating PAP therapy have primarily focused on patients with stable disease, although at least a third will present with acutely decompensated disease. Treatment considerations regarding PAP need to encompass the timing of intervention, response to therapy, and the longer-term impact on patient outcomes. We need to gain a better understanding of the different OHS phenotypes beyond the presence or absence of OSA and how these traits influence the response to various PAP therapies.

Continuous positive airway pressure (CPAP) is applied in the established treatment of first choice for moderate to severe obstructive sleep apnea syndrome (OSAS). Studies have provided information on different aspects of usage and compliance of CPAP therapy. The chapter presents the data with emphasis on the practical use of CPAP therapy in clinical management of OSAS patients. Positive airway pressure (PAP) is the treatment of first choice for obstructive sleep apnea (OSA) of moderate or greater severity in adults. Applied through a facial interface it is a very effective and safe method of preventing the upper-airway obstructions characteristic of OSA. There remain issues of imperfect patient acceptance and compliance with continuous PAP, uncertainties regarding the role of CPAP in mild OSA, and the desired cardiovascular benefits of CPAP. Techniques of diagnosing OSA and initiating CPAP in a timely and economic manner continue to evolve.