Reminding someone to breathe might sound as a strange instruction. But do you know up to 50% of men and 25% of women in the middle-aged population suffer from a condition called obstructive sleep apnea (OSA) (1)?
OSA is a disorder whereby a person pauses breathing several times during sleep, causing oxygen supply to the brain and other tissues to cut and carbon dioxide to accumulate. Each episode can last up to 10 seconds, with the tongue falling backward to obstruct airflow. We do not consciously tell ourselves to breathe; the brain does that for us. Electrical impulses from the brain to the respiratory muscles control contraction and relaxation, ensuring continuous airflow in and out of our lungs. Therefore, a decrease in these electrical signals will result in decreased activity of the respiratory muscles
Other causes of OSA include congested nasal passages, enlarged tonsils, accumulation of fluid in the upper airway and most importantly, obesity (2). Loud snoring, waking up suddenly gasping for air, lack of energy during the day, insomnia, mood swings and even a decreased interest in sex are symptoms of OSA. However, snoring should not be used as a predictive value of OSA.
Obesity is the largest contributor to OSA. Accumulation of fat at the base of the tongue will cause narrowing of the airways, and obese people are also known to have reduced lung volume. Interestingly, the reverse is also true: OSA has shown to cause obesity. Patients have reported substantial weight gain after the onset of OSA symptoms (3). Insufficient or disturbed sleep results in quickened energy depletion during the day causing a person to crave for sugar-rich snacks. When this habit prolongs, weight gain becomes inevitable.
In children, the main cause of OSA is enlarged tonsils. The occurrence of OSA in children is a call for concern. The disorder causes learning problems, growth problems and more seriously, pulmonary hypertension, which left untreated could lead to death. Moreover, the risk of OSA in children with Down’s Syndrome is significantly higher, affecting up to 80% of them (4).
Enlarged tonsils, the leading cause of obstructive sleep apnea in children. Source: http://www.kidshealth.org.nz/sites/kidshealth/files/images/Enlarged_tonsils.jpg
During normal sleep, our blood pressure decreases by about 10-20% because the various systems in our body are functioning at a minimal rate. BP increases just before we wake up and it peaks shortly after waking. However, OSA patients experience increased BP during sleep and wakefulness, which explains the association between OSA and hypertension (5). Another symptom of OSA is the abnormal mixing of gases (oxygen and carbon dioxide) in the blood vessels caused by frequent gasping for air during sleep which brings sudden bursts of oxygen into the body.
The effects of OSA on one’s lifestyle can be pronounced. The arousals, or awakenings, required to break the breathing difficulties in OSA cause sleep fragmentation (frequent interruption of sleep) and reduced sleep quality. Sleep fragmentation is a known trigger of metabolic disorders, including insulin resistance, which may lead to type 2 diabetes (6). Daytime sleepiness and daytime impairment, including sleepiness while driving, are also characteristic of sleep fragmentation. Patients who received even 8-10 hours of total but interrupted sleep, experience severe daytime sleepiness (7).
The potential pathways and clinical presentations that could be caused by OSA. Adapted from Hoyos et. al, 2017.
OSA patients should declare their condition and be assessed prior to any major surgical procedures, because there is a considerable risk of morbidity and mortality. A recent study has reported that OSA patients undergoing general and orthopaedic surgeries have exhibited severe chest complications possibly due to obesity and upper airway abnormalities (8).
A large cohort study conducted in India found the incidence of OSA in stroke patients to be as high as 59%. This finding further reiterates the huge cardiological implications that OSA has. The authors also reported that post-stroke OSA patients had a longer recovery period and hence required longer hospital stay (9).
All these being said, it is not entirely doom and gloom. The good news is, OSA is treatable. In children, younger than 18 years, the first line of intervention is adenotonsillectomy, the removal of adenoids and the tonsils. Adenoids are lymph tissues situated at the roof of the mouth and frequently get enlarged in children during a throat infection, which might obstruct breathing. Adenotonsillectomy is a rather simple day surgery but performed under general anesthesia. However, obese children have shown to respond poorly to this intervention. Therefore, weight management must be advised prior to surgery (10).
In adults, continuous positive airway pressure (CPAP) is the first line of treatment. The CPAP device is a simple machine that supplies a constant pressure through a hose and a mask. However, despite its success, CPAP has poor adherence and compliance rate mainly because of the discomfort of wearing a mask to sleep (11). Patients complain of sleeplessness, dry mouth and a leaky mask if it is not of the right size.
CPAP machine. Source: http://www.topsnoringmouthpieces.com/wp-content/uploads/cpap-machine.jpg
For such patients, a surgery to shift the mandible (lower jaw) might be an alternative. But this surgery poses considerable risks on the patient. Another, less invasive option would be the tongue retaining device (TRD). This method employs a small suction cup to hold the tongue, preventing it from falling back and obstructing airflow (12).
Tongue retaining device. Source: https://i.ytimg.com/vi/cHj7EsjSvVk/sddefault.jpg
In conclusion, OSA is a serious condition, but very successful interventions do exist. As with any other condition, OSA requires early detection to prevent further detriment.
- Erna S. Arnardottir, Erla Bjornsdottir, Kristin A. Olafsdottir, Bryndis Benediktsdottir and Thorarinn Gislason. (2016). Obstructive sleep apnoea in the general population: highly prevalent but minimal symptoms. European Respiratory Journal, (47).
- Shahrokh Javaheri, Ferran Barbe, Francisco Campos-Rodriguez, Jerome A. Dempsey, Rami Khayat, Sogol Javaheri, Atul Malhotra, Miguel A. Martinez-Garcia, Reena Mehra, Allan I. Pack, Vsevolod Y. Polotsky, Susan Redline, Virend K. Somers. (2017). Sleep Apnea Types, Mechanisms, and Clinical Cardiovascular Consequences. Journal of the American College of Cardiology, 69(7).
- Simon A. Joosten, Garun S. Hamilton, Matthew T. Naughton. (2017). Impact of Weight Loss Management in OSA. Chest, 935.
- David G. Ingrama, Alvin V. Singh, Zarmina Ehsan, Brian F. Birnbaum. (2017). Obstructive Sleep Apnea and Pulmonary Hypertension in Children. Paediatric Respiratory Reviews (in press).
- S. Justin Thomas, David Calhou. (2017). Sleep, insomnia, and hypertension: current findings and future directions. Journal of the American Society of Hypertension (in press).
- Camilla M. Hoyos, Luciano F. Drager, Sanjay R. Patel. (2017). OSA and cardiometabolic risk: What’s the bottom line?. Respirology.
- Edward J. Stepanski. (2002). The Effect of Sleep Fragmentation on Daytime Function. Sleep, 25(3).
- Johan Verbraecken, Jan Hedner, Thomas Penzel. (2017). Pre-operative screening for obstructive sleep apnoea. European Respiratory Reviews, 26.
- D. Menon, S. Sukumaran, R. Varma, A. Radhakrishnan. (2017). Impact of obstructive sleep apnea on neurological recovery after ischemic stroke: A prospective study. Acta Neurologica Scandinavica doi:10.1111/ane.12740
- Kun-Tai Kang, Peter J. Koltai, Chia-Hsuan Lee, Ming-Tzer Lin, Wei-Chung Hsu. (2017) Lingual Tonsillectomy for Treatment of Pediatric Obstructive Sleep Apnea A Meta-analysis. JAMA Otolaryngol Head Neck Surgery doi:10.1001/jamaoto.2016.4274
- Ludovico Messineo, Roberto Magri, Luciano Corda, Laura Pini, Luigi Taranto-Montemurro, Claudio Tantucci. (2017) Phenotyping-based treatment improves obstructive sleep apnea symptoms and severity: a pilot study. Sleep & Breathing doi: 10.1007/s11325-017-1485-6
- Edward T. Chang, Camilo Fernandez-Salvador, Jeremy Giambo, Blaine Nesbitt, Stanley Yung-Chuan Liu, Robson Capasso, Clete A. Kushida, Macario Camacho. (2017). Tongue retaining devices for obstructive sleep apnea: A systematic review and meta-analysis. American Journal of Otolaryngology – Head and Neck Medicine and Surgery (in press)