The Sleep Disease: Obstructive Sleep Apnoea - Essay Example

? Obstructive Sleep Apnoea Executive summary The prime focus of the paper concentrates around the perimeter as well as the nucleus of the sleep disease known as obstructive sleep apnoea (OSA). Initially highlight is made on the identification and detailed elaboration of the evolution and the basic symptoms related with the disease. The focus is then shifted on the gender analysis of the disease, i.e, the degree of predominance on the male and female. The risk factors which encircle the disease are explained with perfect correlation. The management of the disease is complex and the elaboration of the step by step diagnosis process is described. The conventional and popular treatment like CPAP, VPAP, and APAP along with development of new therapies and their respective operating mechanisms are explained. Lastly the widening future perspective is mentioned with special emphasis on the prevalence of the disease on the infants. 1. Introduction Obstructive sleep apnea is a pathological disorder generally found with cyclic upper airway obstruction with the narrowing of the respiratory passages during sleep. A general trend that follows with this disorder is that the majority people affected are overweight with higher deposits of fatty tissues in their respiratory passages with hyper normal size of soft palates and tongues (Obstructive Sleep Apnea, n.d.). Adverse consequences of this disorder are related with excessive daytime sleepiness, cognitive dysfunction, retarded work performance, anxiety, difficulties in personal relations, increased risk of fatal and non fatal automobile accidents leading to the loss of human life and huge economical burden in the modern world. Thus the study of this disorder in its core is a necessity and synchronous analysis of this disorder is elucidated in the paper from problem identification to functional remedial measures. 1.1 Historical background Years after the World war, medical science saw new dimensions in the psychological treatments which included brain wave patterns and rapid eye movement (REM). During 1960s, several investigators participated in the explanatory and quantitative analysis of human and animal sleep with related changes in subsequent stages of development. Development revealed the phenomenal concept of duality of sleep which stated that sleep generally consisted of two distinct organismic states that is REM sleep and non-REM sleep. Fig.1 General Structure of sleep (Dement, 1998) Obstructive Sleep Apnoea (OSA) was first diagnosed in Europe in the year 1965 by two groups Gastant et al, Jung and Kuhlo. This disorder was named as the “Pickwickian syndrome” a decade earlier with the misattribution that the daytime somnolence is a cause hypercapnia (excess of carbon di oxide in the body) and it would have not unfurled transparently until Italian neurologist Elio Lugaresi became deeply engrossed in the study of the Obstructive Sleep Apnoea (OSA) and tracked down the problem with unparalleled zeal and set the platform for its further research (Dement, 1998). Throughout the 1970s the only effective treatment for acute OSA was chronic tracheostomy, which generated severe constraints and was regarded as a barrier to the expansion of the sleep medicine. The phase of 1980s ushered with the development of alternative method like Uvulopalatopharyngoplasty. In recent decade awareness has been greatly spread and facts reveal that OSA afflicts around 30 million people in USA and many millions around the globe. The disorder is found to vary among different age groups depending on the way of diagnosis of the disorder (Dement, 1998). 1.2 Epidemiology and Prevalence of apnea The fundamental features of OSA are generally featured by frequent instances of apnea and hypopnea while in slumber. In adults undiagnosed OSA is very common wide severity, cardiovascular and behavioral disorders. A need for better credit and management of severe and symptomatic OSA is highly necessary (Young et al, 2002). The prevalence of OSA has been estimated to vary in the range of 2 to 10 percent worldwide and the risk factors which are significantly dependant are namely advanced age, male sex, obesity, family history, craniofacial abnormalities, smoking and alcohol consumption. The frequent medical indications are heavy snoring. The overall estimation across different countries shows 3 to 7 per cent predominance among the adult men, 2 -5 per cent in the adult women in the general population with rate of prevalence is more in men than in women. Studies Study Population Age (in years) Prevalence ( %) Study 1 American men and women 30-60 Men: 4*-25# Women: 2*-19# Study 2 American men 20-100 17# Study 3 American men and Women 20-100 Men:3.9* Women:1.2* Study 4 Spanish men and women 30-70 Men:14*-26# Women: 7*-28# Study 5 Chinese men 30-60 4.1*-8.8# Study 6 Chinese women 30-60 2.1*-3.7# Study 7 Korean men and women 40-69 Men: 4.5*-2.7# Women: 3.2*-16# Study 8 Indian men 25-65 7.5*-19.5# Study 9 Indian men and women 30-60 Men: 4.9*-19.7# Women: 2.1*-7.4# Table 1. (Lam et al, 2009, p. 167) [* Obstructive sleep apnoea syndrome is defined as apnoea-hypopnoea index >=5 with excessive daytime sleepiness, # Obstructive sleep apnoea is defined as apnoea-hypopnoea index>=5. The studies were assessed with standard polysomnography] From the above table it can be inferred that OSA is more predominant in men who is approximately 2 to 3 times than that of women. The table also infers that OSA is quite rigorous in the developing countries. The exaggerated prevalence of OSA among the Americans, Indians was mainly signified with the increased obesity indices (Lam et al, 2009, p. 167). 2. Pathophysiology and pathology 2.1 Anatomic abnormalities The predominance of OSA is inclined more towards the persons with prior obesity prevalence. Some patients also face obstacles in the airway obstacle due to receding jaw resulting in inadequate space for the tongue. These anatomic abnormalities reduce the cross-sectional area of the upper airway and reduced airway muscle tone during sleeping and the pull of gravity also hinders the air flow during the respiration process. Snoring may occur due to initial incomplete obstruction. The airway may get permanently obstructed with rolling of the patients over on his or her back (Victor, 1999). 2.2 Frequent arousals In incomplete obstruction (hypopnea) or total (apnea), the patient is found to resist in breathing problem and is generally aroused from the sleep. The arousals are partial and are generally not detected by the patients despite the fact that it occurs around hundreds of time in the night. The occurrence of obstruction is frequently connected with the decrease in the oxyhemoglobin saturation (Victor, 1999). 2.3 Frequent arousals and sleeping disorder With each arousal events, the muscle tone of the tongue gets increased which in turn enhance the obstruction and ends the apneic occurrences leading to loud snoring. Severe apnea may have major concerns regarding upper airway obstruction with the rate of occurrence at hundred or more per hour. Multiple arousals in the night are also said to be the positive predictor of daytime sleepiness among the OSA patients. Unrestful sleep and feeling sleepier in the morning are generally among the frequent complains of the OSA patients (Victor, 1999). 2.4 Brain injury may cause obstructive sleep apnoea The patients of OSA are found to complain about tiredness, drowsiness or awakening without a feeling of refreshment. This can be the underlying mechanism of the severe brain damage or injury, a condition which is known as central sleep apnoea inculcated with the blockage of airways during sleep. The vulnerability of OSA increases post Traumatic Brain Injury (TBI) which leads to the development of obesity in turn. The patients with TBI are known to have reported exercising over eating practices and become prone to more sedentary adaptation with lower exercise tolerance and excessive tiredness. The treatment centers for the TBI patients have been diagnosed with higher obesity trends (Singman, n.d.). Thus brain injury and obesity are in a cause-effect relationship and results in a direct relation which is depicted in the diagram below: Fig 2. (Singman, n.d.). In the above diagram, the arrows also illustrate the reversible and counter reversible dynamics of the above stated mechanism. 2.5 Obese and old people are prone to the disease Obesity is a major risk factor for the development of OSA and it is believed to have a keen intersection in the alteration of the anatomic features with the predisposition of the upper airway obstruction during sleep with increasing adiposity around the area of pharynx and in other parts of the body. Central obesity is associated with the decrease in the lung volume resulting in the loss of ‘caudal traction’ on the upper airway thus increasing the ‘pharyngeal collapsibility’. In a community based group of middle-aged Caucasian subjects were found to develop four times increase in the sleep apnoea with change in 1-SD increase in the body mass index (BMI). The per cent of subjects from the community with OSA were moderately overweight but healthy. The patients with severe obesity with body mass index greater than 40 the prevalence markedly increased to around 40 to 90 percent. Fig. 3 (Lam et al, 2010, p.167) The above diagram represents that a small change in obesity leads to a greater change in the intensity of OSA. Age is also a principal variable affecting OSA. The prevalence enhances after 65 years of age. But when the prevalence is checked by the body mass index (BMI), the severity of the disorder appears to decrease with age. Increased pervasiveness of sleep apnoea in the elderly persons includes enhanced deposition of fat in the parapharyngeal area with broadening of the soft palate and alterations around the area of pharynx (Lam et al, 2010, p.167). 2.6 Decreased muscle tone along the air way is a cause ‘Decreased airway muscle tone’ at the time of slumber and the gravitation pull in the supine position decreases the airway sizes thereby obstructing the proper air flow during respiration. The individuals with apnea continuously stops their breathing during sleep and thus results in the lowering of the oxygen levels. In some serious cases, hyper blood pressure, cardiac arrhythmia and fatal heart attacks may take place (Systems Affected by Myotonic Dystrophy, n.d.). 3.1 Management of obstructive sleep apnoea The treatment for sleep apnoea largely depends on the severity of the problem. With the provided data on the long-term complications of sleep apnoea, it is generally necessary for the patients to treat the problem with serious emergency without wasting time. Emphasizing only on the treatment of snoring will not treat sleep apnoea. The disorder is associated with cardiac problems and strokes and for this reason sleep disorder specialists or doctors are the best to tackle the issue. The most efficient management techniques for sleep apnoea are the devices which deliver somewhat pressurized air to make the throat released at night. There are large numbers of such devices present for its treatment. Elaboration is made in the therapies section (Obstructive sleep apnea – Treatment, n.d.). The next segment will deal with the diagnosis of the disorder. 3.1 Diagnosis 3.1.1 History of patients The patients with significant sleep apnoea are commonly found to be ignorant about their disorders. The problems the patient face are generally reported to the doctors by the spouses or the partners. Rigorous subjective assessment of sleepiness of both the patient and partner is important as it is unlikely that the patients will accept the course of treatment unless they expect the positive gains with the reduction in the subjective sleepiness or in the improvement of the work performance (Management of Obstructive Sleep Apnoea/Hypopnoea Syndrome in Adults, 2003, p.6). 3.1.2 Symptoms The patients in the early phase may present with non precise indications such as irritability, personality change, work or family troubles or poor attentiveness. These indications may occur from the result of poor sleep quality and a high index of obstructive sleep apnoea (OSA) is required for allowing the diagnosis to be executed. The primal questions which will have to be kept in mind are : a) whether the patients are falling asleep in regular intervals against their will, b) whether the patient often encounter drowsiness while driving, c) whether the patient is experiencing constraints at work because of excessive sleepiness and so on (Management of Obstructive Sleep Apnoea/Hypopnoea Syndrome in Adults, 2003, p. 6). 3.1.3 Characterized by decrease in oxygen levels “The gold standard diagnostic test for OSA is recognized as the overnight in-laboratory polysomnography which involves multi- channel continuous polygraphic recording electroencephalography, electrooculography, electromyography, electrocardiography, nasal pressure transducer (supplemented by thermistor) for nasal airflow, thoracic and abdominal impedance belts for respiratory effort, pulse oximetry, tracheal microphone for snoring, and sensors for leg and sleep position” (Lam et al, 2009, p. 166). The stated recordings will identify the various types of apneas and hyponoeas during the sleeping time. Apnoea is defined to be the total termination of airflow for at least 10 seconds. Three types of apneas are generally encountered. They are obstructive, central and mixed. In obstructive sleep apnoea maintainence of respiratory efforts are established but ventilation diminishes because of the partial or complete occlusion in the upper airway. The Central sleep apnoea occurs when the there is reduction in respiratory efforts paving the way for reduced or absence in ventilation. Mixed apnoea is mostly characterized by starting of the central apneas and ends with the obstructive events. The severity of the sleep apnoea is generally determined with the apnoea-hypopnoea index (AHI) which is the number of the apnoeas and ‘hypopnoeas per hour of sleep’ and the value is generally fixed above 5. The severity increases with rise in the magnitude (Lam et al, 2009, p. 166) 3.2 Therapies The treatment for sleep apnoea largely depends on the severity of the problem and depends upon the types of patients involved including their anatomic, mental states. Three popular therapies are used for curing OSA. They are Continuous positive airway pressure (CPAP), Variable positive airway pressure (VPAP), Automatic positive airway pressure (APAP). 3.2.1 Continuous positive airway pressure (CPAP) The primary diagnosis tool as well as a treatment modality for patients with sleeps apnoea at the same time is the Continuous positive airway pressure. The proponents believe that the patients who suffer from OSA will continue to use CPAP if their symptoms improved. Patients with high probability of OSA it has been seen that standard polysomonography confers no advantage over the ambulatory approach in terms of diagnosis and CPAP titration. When there is inadequate access to polysomnography, the ambulatory approach can be used to advance the management of patients in the need of treatment (Lam et al, 2009, p. 166). 3.2.2 Variable positive airway pressure (VPAP) This system finds its useful applications for the patients with pre existing lung diseases and with excessive carbon dioxide levels. The VPAP devices possess sensing characteristics which determine and vary the appropriate pressure depending on the inhalation and exhalation of a person. Generally greater pressure is required during inhalation rather than on exhalation (Obstructive sleep apnea – Treatment, n.d.). 3.2.3 Automatic positive airway pressure (APAP) The devices modify involuntarily the air pressure for individual patient. For some patients, the APAP plans can be used to start with the treatment at home with no supervision. The patients with chronic lung disease, heart failure, obesity hypoventilation syndrome, who do not snore, are not generally considered for APAP. The general pressure is kept small until there is problem recognition. During this time, the pressure gets automatically increased randomly. The pressure is usually less when there is no harm but is slowly increased when they are identified. The pressure is subsequently increased and lowered in response to the problems or their absence (Obstructive sleep apnea – Treatment, n.d.). 3.3 Development of therapies There are many developments of therapies. However the scope of discussion is limited. The REM sleep suppressant therapy and use of chemicals like Fluoxetine and paroxetine are used in these therapies which entail significant REM sleep suppressant effects. Among other therapies are Ventilatory Stimulants like Methylxanthine derivatives, Opioid antagonists, Medroxyprogesterone and estrogen therapy, Supplemental Oxygen and so on (Veasey et al, 2006, pp. 1039-1041). 4. Future perspective 4.1 Funding of research on disease by scientists Awareness for curbing the disease has emerged with great heights with supporting endeavors from several agencies. Since the establishment of the American Academy of Sleep Medicine in 1998, the government has been providing more than $5.2 million in funding to support 73 projects in the domain of sleep medicine and sleep research. In 2012, ASMF has awarded five Physician Scientist Training Awards of $75,000 each, two Bridge to K Awards of $75,000 each, one ABSM Junior Faculty Research Award of $50,000; two Educational Projects Awards of $75,000 each, and one Humanitarian Projects Award of $10,000.The award will allow the assist young investigators at a grave stage in their career to opt for a different career track and contribute optimally for the social welfare (American Sleep Medicine Foundation, 2012). 4.2 Identification of disease on infants OSA is generally thought to affect the 1 to 3 percent of the children and is caused through the adenotonsillar hypertrophy and other causes like craniofacial abnormalities, obesity and neuromuscular disease. The children do not encounter hypersomnolence that occurs in adults but often faces excessive sweating or developmental delay. The diagnosis of OSA in children is done in a ‘pediatric sleep laboratory’ using ‘nocturnal oximetry and polysomnography’ which will help those children from tonsillectomy and adenoidectomy. Children experiencing partial relief from tonsillectomy and adenoidectomy may reap benefit from the nasal continuous positive airway pressure (CPAP), which has been found to be safe as well as effective measures in children (Thiedke, 2001). 5. Summary The paper dealt with the identification of the obstructive sleep apnoea starting from the fundamentals to detailed elaboration. Historical background has been proliferated in order to explore the mechanism of exploration of the disease. The prevalence of the disease has been mainly dominated in the male than the female. Obesity, brain injury, decrease in the muscle tone has been found to ignite the disease to a great height. After analyzing the symptoms and disorders management of the disease with diagnosis and three primal treatment therapies i.e, CPAP, VPAP, and APAP along with development of new therapies are elucidated. Lastly the identification and analysis of the disease among the infants is made along with the exploration of the future perspective. 6. Conclusion There has been a continuous interaction and enhancement in the development of the upper airway region through several complex process filtering including genetic as well as the environmental factors. The studies divulge to the fact that OSA is complex diseases with great complexities. From the focus on the identification, the historical background and the root causes of the disease reveal that that the obesity and age are significant variables in the vulnerability of the disease and results in the blockage of the upper air ways. Modern medical science has developed and is on the verge of designing new mechanisms for the improvement or the development of the upper airways and also stresses on the mass awareness. References 1. American Sleep Medicine Foundation, 2012, viewed 7 June 2012 2. Dement, W. C. 1998, ‘The study of human sleep: a historical perspective’, Thorax, vol.53, no.3, viewed 7 June 2012 3. Lam, S.K. Jamie, C.M. & B. Lam, 2010, Obstructive sleep apnoea: Definitions, epidemiology & natural history, viewed 7 June 2012 4. ‘Management of Obstructive Sleep Apnoea/Hypopnoea Syndrome in Adults’, 2003, viewed 7 June 2012 5. ‘Obstructive Sleep Apnea’, n.d., viewed 7 June 2012 6. Obstructive sleep apnea – Treatment, 2011, viewed 7 June 2012 7. Singman, E L, n.d. ‘The Ophthalmology of TBI-Associated Sleep Apnea’, viewed 7 June 2012 8. ‘Systems Affected by Myotonic Dystrophy’, n.d., viewed 7 June 2012 9. Thiedke, C. C. T, 2001, ‘Sleep Disorders and Sleep Problems in Childhood’, Am Fam Physician Vol. no. 15.63 , no. 2, viewed 7 June 2012 10. Victor, L. D 1999, ‘Obstructive Sleep Apnea’, viewed 7 June 2012 11. Veasey et al, 2006, ‘Medical Therapy for Obstructive Sleep Apnea: A Review by the Medical Therapy for Obstructive Sleep Apnea Task Force of the Standards of Practice Committee of the American Academy of Sleep Medicine’, viewed 7 June 2012 12. Young et al, 2002, ‘Epidemiology of Obstructive Sleep Apnea: A Population Health Perspective’, Am. J. Respir. Crit. Care Med. 2002, Vol. no. 165, no. 9, pp. 1217-1239, viewed 7 June 2012 Read More