A review of therapies for the overlap syndrome of obstructive sleep apnea and chronic obstructive pulmonary disease

Abstract

Obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) are common chronic diseases. These two noncommunicable diseases (NCDs) are prevalent among approximately 10% of the general population. Approximately 1% of the population is affected by the co-existence of both conditions, known as the overlap syndrome (OS). OS patients suffer from greater degrees of nocturnal oxygen desaturation and cardiovascular consequences than those with either condition in isolation.Besides OS, patients with COPD may suffer from a spectrum of sleep-related breathing disorders, including hypoventilation and central sleep apnea. The article provides an overview of the pathogenesis, associated risk factors, prevalence, and management of sleep-related breathing disorders in COPD. It examines respiratory changes during sleep caused by COPD and OSA. It elaborates upon the factors that link the two conditions together to lead to OS. It also discusses the clinical evaluation and diagnosis of these patients. Subsequently, it reviews the pathophysiological basis and the current evidence for three potential therapies: positive airway pressure therapy [including continuous positive airway pressure (CPAP) and bilevel positive airway pressure], oxygen therapy, and pharmacological therapy. It also proposes a phenotypic approach towards the diagnosis and treatment of OS and the entire spectrum of sleep-related breathing disorders in COPD. It concludes with the current evidence gaps and future areas of research in the management of OS.

Dysregulation of the Nitric Oxide/Dimethylarginine Pathway in Hypoxic Pulmonary Vasoconstriction—Molecular Mechanisms and Clinical Significance

“…Pulmonary hypertension is also one pathological consequence of chronic intermittent hypoxia in obstructive sleep apnoea syndrome (OSAS); increased pulmonary arterial pressure may occur during sleep, but also during waking hours ( 29 ). Whilst clinically relevant pulmonary hypertension is rare in pure OSAS, it may occur much more frequently in the so-called overlap syndrome, i.e., the combined occurrence of OSAS and chronic obstructive pulmonary disease (COPD) ( 30 ). Although there still remain gaps in our understanding of the pathophysiology of this relationship ( 67 ), one relevant observation helping us to understand the association of OSAS with vascular disease in both, the pulmonary and systemic circulation, is the presence of endothelial dysfunction, i.e., the inability of the vascular endothelium to generate physiological amounts of NO as required to maintain vasodilator tone ( 68 ).…”

Elevated Monocytic Interleukin-8 Expression under Intermittent Hypoxia Condition and in Obstructive Sleep Apnea Patients

“…Accumulating studies reveal that OSA is an independent risk factor for hypertension and consequent cardiovascular morbidities, such as myocardial infarction, heart failure, nocturnal dysrhythmias and pulmonary hypertension [ 3 ]. Currently, OSA can be treated by means of positive airway pressure therapy, oxygen therapy and pharmacological therapy [ 4 ]. Surgical intervention should be considered in patients who are noncompliant with the above treatments or in whom they fail [ 5 ].…”

Alternative Sleep Apnea Treatment: Reply

“…Currently, the overlap syndrome receives special attention in the fields of pulmonology and sleep medicine because of its greater degrees of nocturnal oxygen desaturation and cardiovascular consequences than those with either condition in isolation. 5 Although this is not the original scope of our study, the overlap syndrome also needs to be paid more attention by anesthesiologists because of the possible development of severe sustained and episodic hypoxemia after surgery, leading to poor postoperative outcome. To date, we do not know whether continuous or bilevel positive airway pressure therapy is effective and what level of oxygen concentration is appropriate for postoperative respiratory management in patients with the overlap syndrome.…”