Dr Randeep Singh
Obstructive sleep apnea is a sleep-related breathing disorder that results from the partial or complete collapse of the upper airway during sleep. Apneas refer to a temporary cessation of breathing that lasts for at least 10 seconds, resulting in low blood oxygen levels, negative intrathoracic pressure, fragmented sleep and arousal from sleep. Sleep fragmentation from apneas leads to excessive daytime sleepiness in such patients.Not everyone who snores has apnea. In obstructive sleep apnea, the snoring is accompanied by breathing pauses due to upper airway collapse, followed by choking or gasping at night.Patients with OSA present with complaints of excessive daytime sleepiness, unrefreshing sleep, loud snoring, choking or gasping observed by patient’s bed partner or family member, nighttime awakenings, morning headaches, decreased libido, fatigue or tiredness. Most patients with OSA have upper airway narrowing due to deposition of fat in the pharyngeal muscles and parapharyngeal folds or craniofacial abnormalities.
What causes
Risk factors predisposing to obstructive sleep apnea include obesity (BMI >30 kg/m2), large neck size (>17″ in males, >16″ in females), male gender, postmenopausal women, elderly patients, enlarged tonsils, genetic factors, untreated hypothyroidism, craniofacial abnormalities, smoking, alcohol and sedative use.
Who should be evaluated for OSA?
Obstructive sleep apnea should be suspected in all patients with symptoms of excessive daytime sleepiness, fatigue or unrefreshing sleep and high risk for OSA. Patients at high risk for OSA include obese patients (BMI >30 kg/m2), type 2 Diabetes Mellitus, treatment-refractory hypertension, arrhythmias, stroke and driving populations.
Diagnosis of OSA
Many patients of OSA are diagnosed after years of symptoms of OSA. OSA can be diagnosed using either sleep-lab based Polysomnography (PSG) test or home sleep apnea testing(HSAT). Polysomnography is the gold standard test for the diagnosis of OSA. Both sleep and respiratory parameters – apneas and hypopneas can be measured. OSA severity is categorized using the Apnea-hypopnea index (AHI), defined as the total number of apneas and hypopneas per hour of sleep. An AHI of < 5 events per hour is normal, 5 to 14.9 is mild OSA, 15to 29.9 is moderate OSA, and more than 30 is considered severe OSA. However, in most patients, diagnosis can be made using home sleep apnea testing. If there is a high suspicion for OSA and the home sleep apnea results are negative for OSA, sleep-lab based polysomnography is recommended.
Treatment options
There are medical, surgical and behavioral options available for the treatment of OSA. Continuous positive airway pressure (CPAP) is the mainstay of treatment for symptomatic or moderate to severe obstructive sleep apnea patients. CPAP devices continuously deliver positive pressure during both inspiration and expiration. These devices act as a splint and prevent airway collapse during sleep. Oral appliances (Mandibular repositioning devices) are custom made by dentists. These devices are recommended for patients with mild to moderate OSA or those who refuse CPAP or are unable to use CPAP.
Surgical procedures for OSA aim to modify upperairway soft tissues and relieve the sites of airway narrowing. These include uvulopalatopharyngoplasty or laser-assisted uvulopalatoplasty and radiofrequency-based procedures. Hypoglossal nerve stimulation is one of the newer modalities of treatment.OSA treatment strategies include lifestyle modifications and weight reductions for obese patients. Bariatric surgery in the morbidly obese can produce dramatic reductions in weight and substantial improvements in OSA. Other OSA treatment strategies include avoidance of alcohol or sedatives, avoidance of sleeping in the supine position.
Prognosis
OSA is associated with an increased incidence of hypertension, diabetes mellitus, heart failure, stroke and motor vehicle accidents. OSA can have a significant negative impact on patient’s overall quality of life. Effective treatment of OSA improves daytime sleepiness, quality of life, mood. It reduces health care costs, and overall improvement depends on adherence to treatment. As with other chronic diseases, OSA requires long term follow up and management.
(The author is a Chest Physician, Govt. Chest Disease Hospital, GMC Jammu.)
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