Background: Obstructive sleep apnea (OSA) is a common disorder of breathing but is probably underappreciated as a perioperative risk factor.
Methods: This review is based on pertinent articles, published up to 15 August 2015, that were retrieved by a selective search in PubMed based on the terms "sleep apnea AND anesthesia" OR "sleep apnea AND pathophysiology." The guidelines of multiple specialty societies were considered as well.
Results: OSA is characterized by phases of upper airway obstruction accompanied by apnea/hypoventilation, with hypoxemia, hypercapnia, and recurrent overactivation of the sympathetic nervous system. It has been reported that 22% to 82% of all adults who are about to undergo surgery have OSA. The causes of OSA are multifactorial and include, among others, an anatomical predisposition and /or a reduced inspiratory activation of the bronchodilator muscles, particularly when the patient is sleeping or has taken a sedative drug, anesthetic agent, or muscle relaxant. OSA is associated with arterial hypertension, coronary heart disease, and congestive heart failure. It can be assessed before the planned intervention with polysomnography and structured questionnaires (STOP/STOP-BANG), with sensitivities of 62% and 88%. The utility of miniaturized screening devices is debated. Patients with OSA are at risk for perioperative problems including difficult or ineffective mask ventilation and/or intubation, postoperative airway obstruction, and complications arising from other comorbid conditions. They should be appropriately monitored postoperatively depending on the type of intervention they have undergone, and depending on individually varying, patient-related factors; postoperative management in an intensive care unit may be indicated, although no validated data on this topic are yet available.
Conclusion: OSA patients need care by specialists from multiple disciplines, including anesthesiologists with experience in recognizing OSA, securing the airway of OSA patients, and managing them postoperatively. No randomized trials have yet compared the modalities of general anesthesia for OSA patients with respect to postoperative complications or phases of apnea or hypopnea.