“Do not go to sleep, so many people die there” – Mark Twain
Obstructive sleep apnea syndrome (OSAS) is by far the single most common disorder seen at sleep centers and is responsible for more mortality and morbidity than any other sleep disorder. OSA is the cessation of airflow for 10 seconds or more during the night due to partial or full collapse of airway. The reduced or absent airflow results in hypercapnea (high carbon dioxide) and hypoxia (low oxygenation).
The sufferer is forced to increase his breathing effort against the collapsed airway. This means that the sufferer arouses to a lighter stage of sleep, which leads to sleep fragmentation and the person wakes up unrefreshed.
Most people are unaware of the disorder and its impact on overall health. Common signs and symptoms include loud snoring and excessive day time sleepiness, morning headaches, loss of concentration and waking up choking.
It is a life-altering and life-threatening disorder. If left untreated, it increases the risk of heart attack, stroke, heart failure, Type II diabetes and hypertension. Not to mention other consequences like the risk of work-related accidents and traffic accidents.
Three decades of research has proved beyond doubt that snoring and OSA are linked to and directly and indirectly contributing to cardiovascular morbidity and mortality – hypertension, cardiac failure, cardiac rhythm disorders, strokes, dyslipidemias, atherosclerosis and increased platelet activation.
Although OSAS was identified more than three decades ago, a majority of physicians have had no formal training in recognizing or treating the condition. The prevalence of OSA in the world is 2-4 percent in middle-aged adults, which is similar in magnitude to the prevalence of major diseases such as asthma and diabetes.
Although the prevalence is stated as 2-4 percent, two independent studies have shown that 24 percent of asymptomatic men and 9 percent of asymptomatic women qualify for the basic criteria of suffering from OSA. Clearly there is large amount of disease under the surface.
Furthermore, new information concerning the diagnosis and treatment of obstructed breathing during sleep is emerging faster than older concepts can be disseminated. The result is that most patients with treatable sleep-related breathing disorders currently remain undiagnosed.
Some of the risk factors aggravating OSA include obesity, neck circumference greater than 1 inch or 40 cm, gender positive family history, craniofacial anatomy, alcohol ingestion, use of sedatives, sleep deprivation, supine sleeping position and smoking. To elaborate on some points: Males are three-nine times more likely to have OSA, while the risk for women increases with obesity and after menopause. This apart, the rick increases two-four fold if a first-degree relative suffers from OSA.
An observational study was recently conducted by this author at Sir Ganga Ram Hospital on the patients admitted to the Department of Cardiology for various cardiac problems. The patients were randomly selected for age, sex and body mass index (BMI). Their sleep study was performed to estimate the prevalence of obstructive sleep apnea in cardiac patients.
The figures showed that nearly 97 percent of the patients had significant sleep apnea and nearly 58 percent of these were of the severe category. Also, in this group, there was no correlation with BMI. Even patients with low BMI showed significant prevalence of the disease, which means even thinner patients were at risk.
But remedy is at hand. OSA can be easily diagnosed through a sleep study conducted by a trained professional. The physiological parameters of the person undergoing the study are monitored, recorded and analysed to detect the sleep disorder.
Like any diagnostic test, sleep study or polysomnography is used to diagnose, or rule out, a variety of sleep disorders including OSA. One can also ask one’s physician about screening questionnaire.
Continuous positive airway pressure (CPAP) is the gold standard for the treatment of OSA. CPAP treats OSA by applying positive airway pressure through a nasal mask. This positive pressure acts as a pneumatic splint to hold the upper airway open throughout the entire breathing cycle.
It is recommended that the level of positive airway pressure be determined for each patient during a sleep study. By providing a pneumatic splint, the positive pressure prohibits the airway from collapsing, ensuring that air flows freely to the lungs.
(Sanjay Manchanda is a senior somnologist and chairs the Department of Sleep Medicine at Sir Ganga Ram Hospital in New Delhi. He can be reached at Dr_sleep2000@yahoo.com).