Historical Context of Sleep Apnea - Essay Example

? Obstructive Sleep Apnea 0 Background This essay seeks to discuss the disease, Obstructive sleep apnea. It covers the following; pathophysiology, epidemiology, historical context, the management and treatment of the disease, current developments of the disease and a conclusion. In a nut shell, obstructive sleep apnea gets characterized by breath cessation during sleep. It usually occurs when there is obstruction at the pharynx (Davidson’s 2007, p. 666). The disease causes stop of breathing for (10) ten seconds a condition caused by reduced motor tone of the tone and palatoglossus and genioglossus muscle. More so, the collapse of upper airway during sleep causes obstructive sleep apnea which results from negative oropharyngeal pressure and narrowing of the oropharyngeal lumen. The disease presents with the following symptoms: somnolence, fatigue, headaches, depression, and loud snoring during sleep (Davidson’s 2007, p. 666). 1.1 Historical context of sleep apnea Obstructive sleep apnea is chronic and associated with cardio metabolic sequelae; the disease has existed for the last three decades, and the current society has increased awareness of the disease. The disease contributes to atherosclerosis (Lorenzi 2007, p. 615), and a clinical manifestation of cardio metabolic risk factors such as hypertension, dyslipidaemia, insulin resistance and obesity (Givelber 2005, p. 219). In 1980s researches got conducted in different populations, they defined the disease and informed on the risk factors. Recently, a study called Sleep Heart Health got carried out to compare the effects of obesity on the disease (Tasali 2008, p. 216). The study concludes that the impact of obesity on the evolution of sleep apnea is not major because patients are obese at presentation. Further, research on sleep apnea and the complications on cardio metabolic complications in the last 8 years discovered that the disease has a long term standing illness and imposes economic burden to the society (Giles 2006, p. 2412). 1.2 Epidemiology/ prevalence. Obstructive sleep apnea is a breathing disorder that has existed since 1980s and is now available in many different countries (Takegami, 2008, p. 420). Researchers approximate that 1 per cent in every 5 of American adult develops mild obstruction sleep apnea. Estimations show that, in mid 1990s, 3 per cent to 4 per cent of women, and 6 per cent to 7 per cent of men developed obstructive sleep apnea. Thus, obstructive is more common in men than in women by approximately 2 to 3 times more than that of women (Punjabi 2008, p. 137). The prevalence of sleep apnea is the same in Caucasians and Asians, so the disease has spread in the whole world-developed and developing countries. The disease prevalence is higher among obese subgroup, elderly, and those with different ethnic groups-African –American ethnicity is a risk factor. Increased Obesity indices are the cause of increased prevalence among Americans, Indians and Hispanic adults (Buchanan 2005, p. 431). 1.3 Aetiology/ whole body context Obstructive sleep apnea results due to persistent obstruction of the pharynx at the level of the soft plate leading to cessation of respiratory for 10 seconds occuring for 5 to 30 times (Davidson’s 2007, p. 666). The disease results when the muscles responsible for dilating the tongue reduce tone. These muscles are palatoglossus and genioglossus. The reduction of muscle tone occurs due to; effects of some drugs, alcohol, or neurological problems (Rodriguez 2010, p 838). During sleep, muscle tone reduces leading to failure in dilating the upper airway open, which results to the falling of the pharyngeal patency (Magini 2010, p. 549). It is the persisted of this situation that leads to breathing difficulties during sleep. More so, obstruction of airway occurs due to, deviated nasal septum, nasal congestion, enlarged tonsils, hypertrophy of adenoids and facial trauma. They lead to impaired airway passage (David 2010, p. 720). Similarly, Obstruction sleep apnea results when oxygen level in the blood circulation reduces and the carbondioxide levels rise, signals get send to the brain which in return cause the body to gasp for air hence resulting to waking up from sleep (Powell 2011, p. 665). Anatomically narrowing of palatopharynx and reduced dilation of muscles during sleep causes low oxygen level in the blood thus leading to airway obstruction (Powell 2011, p. 665). More so, reduced level of oxygen in the blood results to hypoxia. Hypoxia has the effect of disrupting body organs from normal functioning by damaging vital body organs and in extreme cases lead to cell necrosis (Akre 2011, p. 426). Further, lack of oxygen in saturation leads to metabolic aciclosis whereby, lactic acid gets produced and released to the body muscle causing continual tiredness (Akre 2011, p. 428). Brain gets injured too, for example, focal cerebral ischemic manifesting in a form of stroke occurring in a localized area. Complete oxygen deprivation results in cerebral infarction affecting multiple areas in the brain. Severe oxygen deprivation results in tachyarrhythmia which includes arterial fibrillation and ventricular tachycardia. The reduction of oxygen levels becomes a risk for diabetic development because it leads to insulin resistance (Magini 2010, p. 549). 2.0 Importance of relevant systems which get affected when sleep apnea is developing Development of obstructive sleep apnea involves some systems in the body. Some of these systems include the cardiovascular system and increased sympathetic nerve activity. More so, obstructive sleep apnea is a predisposing factor for hypertension and myocardial infarction. Obstructive sleep apnea leads to oxygen disaturation, carbondioxide in the blood increases. This raises sympathetic nerve activity to send a message to the brain, which in return sends a distress massage to the body organs causing vasoconstriction of blood vessels. When vasoconstriction occurs blood pressure rises and hypertension develops. Impaired coagulation and platelet function mechanism gets involved. Impaired coagulation leads to development of an occlusive thrombus in the coronary artery thus, blocking the blood flow to the heart hence resulting in ischemic heart disease (Davidson’s 2007, p. 1202). Similarly, severe obstructive sleep apnea results to with tachyarrthmia and atrial fibrillation complications. Central nervous system is also of importance in a patient with obstructive sleep apnea low oxygen saturation in the blood caused by obstructive sleep apnea leads to cerebral infarction through hypoxia related mechanism (Taylor 2008, p. 43). Hypoxia leads to insufficient supply of adenosine triphosphate (ATP), which contributes to membrane pump failure allowing water and sodium in flux into the cells; in return glutamate get released into the extracellular fluid (Miller 2005, p. 101). Glutamate leads to an influx of calcium in to the neurons; this activates intracellular enzymes that complete the destructive process of the cells. The microglia and astrocytes releases inflammatory mediators leading to cell death and cerebral infarction occur (Webber 2005, p. 204). Release of lactic acid into the cells as a result of hypoxia worsens cerebral infarction (Davidson’s 2007, p. 1202), endocrine system is another system of relevant importance in obstructive sleep apnea. Hypoxia leads to insulin resistance leading to onset of diabetes. 2.1 Pathophysiology/ pathology and mechanisms involved in causal of sleep apnea The most important mechanism in obstructive sleep apnea occurs in the structures of the pharynx and the inability of the upper airway dilator muscles to maintain open airway patency (Fletcher 200, p. 189). During sleep, a negative pharyngeal pressure reflex occurs on genioglossus muscle causing the activation of the genioglossus muscle in response to changes. The response is by a negative intrapharyngeal pressure (subatmospheric) (Leung 2009, p. 325). Normal functioning of the mechanism affected to result to obstructive sleep apnea involves the normal sleep cycle which gets classified into two categories, that is rapid eye movement sleep and non-rapid eye movement sleep (Becker 2000, p. 143). During rapid eye movement sleep, the mechanism involves the muscles of the neck, throat and skeletal muscle which allow the tongue and oropharynx to relax to allow airflow. During obstructive apnea airflow to the throat, neck and the tongue areas becomes compromised leading to slight snoring (Pinsky 2002, p. 1023). When airflow decreases, oxygen level in the blood falls to a variable degree which causes a neurological arousal which is a mechanism that stimulates a sudden interruption of sleep (Becker 2000, p. 143). Arousal from sleep occurs as a protective mechanism associated with dilatation of the upper airway dilator muscles. The process involves the activity of genioglossus and palatoglossus muscles in need of creating an equivalent level of sub atmospheric pharyngeal pressure and ventilator response during sleep. This mechanism tries to reverse the changes rapidly by restoring oxygen disaturation and hypercapnia, therefore, reducing apnea severity (Shepard 1990, p. 1253). The ventilator response caused gets controlled by ventilator control stability which plays the role of sensing the disaturation of oxygen during the development of obstructive sleep apnea. Ventilatory control stability gets explained by the use of loop gain concept (Zwillich 1998, p54). Loop gain concept explains the respiratory system stability and how the system responds to perturbation in breathing, for example, arousal. Loop gain concept has two parts, first, chemoresponsiveness of the system which include hypoxic and hypercapnic ventilatory responses (Becker 2000, p. 142). Secondly, the efficiency of carbondioxide excretion refers to a given ventilator to excrete carbondioxide. Division of sensors and effectors makes the ventilatory feedback control system to be vulnerable to instability. Research shows that the disease is prevalent among people with high loop gain, hence the conclusion that, ventilator control instability contributes to the disease. Similarly, high loop gain increases ventilator response to arousal which leads to decreased activity of the genioglossus and palatoglossus muscle (Becker 2000, p. 142). Obstructive sleep apnea gets caused by complete or partial obstruction of airway during sleep. The obstruction occurs at the nasopharynx or oropharynx due to anatomical narrowing. During wakefulness, dilating muscles in the upper airway contract actively during each inspiration in order to preserve oxygen patency (Zwillich 1998, p. 55), while during sleep, tone relaxes, genioglossus and palatoglossus muscle dilating ability to maintain pharyngeal patency falls. Then tone increases resulting to uncompromised breathing during sleep (Davidson’s 2007, p. 667). During wakefulness, patients suffering from obstructive sleep apnea try to compensate anatomically compromised upper airway through protective reflexes that increase upper airway dilator muscle to maintain airway patency (Davidson’s 2007, p. 667). 2.2 Key respiratory related manifestation/clinical characteristics Obstructive sleep apnea manifests by the following; first, excessive somnolence which occurs due to repetitive arousal from sleep as a consequence of low oxygen saturation. Secondly, sleep apnea gets associated with increased inability day work concentration. Thirdly, by complains of fatigued which is as a result of metabolic aciclosis where by lactic acid get released to the skeletal muscles and the person feels extremely tired (Akre 2011, p. 428). Fourthly, the characteristic of snoring episodes during sleeping times, which occurs as a result of obstructed airways at the level of oropharynx or nasopharynx. Snoring occurs as the first alert in obstructive sleep apnea. Snoring occurs due to the weakness of the throat walls which make the throat close during sleep. The airway becomes obstructed when one sleeps supine causing the tongue to fall back thus developing snoring. More so, the use of alcohol and other drugs having the effect of relaxing the throat muscles leads to snoring during sleep. Snoring occurs also as an effect of tissues at the airway coming close to each other hence causing some vibrations which get reflected as snoring. Fifthly, the disease sleep apnea manifests by morning headaches, the reason is that low oxygen saturation in the blood leads to cerebral vasodilation, which leads to headache. Sixthly, by cognitive impairment results from hypoxemia, this impairs the biochemical and hemodynamic state of the central nervous system. The patient then develops difficulties in solving some problems and experiences a short term recall of verbal information. The person suffering from sleep apnea suffers from depression and change of personality (Akre 2011, p. 429). 2.3 Respiratory components associated with obstructive sleep apnea Lungs are a vital body organ involved in the respiratory process. Gaseous exchange takes place in the following parts of the lungs, bronchi, smaller air passages and alveoli (Hutchinson’s 2007, p. 391). The alveoli and the blood stream have a continuous gaseous exchange process between them. Therefore, oxygen gets supplied to the blood stream from the lungs. The obstruction of the airway leads to breathing in of oxygen with low oxygen saturation which results to a rise in pulmonary arterial pressure which at an advanced stage causes pulmonary hypertension (Hutchinson’s 2007, p. 392). The increase in pulmonary arterial pressure causes hypoxic vasoconstriction results to pulmonary vascular remodeling which contributes to the development of pulmonary hypertension. Therefore, the obstruction of the airway causes conditions which leads to lung diseases, while frequent upper airway obstruction and reduced oxygen saturation seen in sleep apnea leads to chronic pulmonary arterial pressure (Hutchinson’s 2007, p. 393). 3.0 Diagnoses of obstructive sleep apnea Diagnosis involves clinical assessment where the patient experiences excessive daytime sleepiness as the main symptom and snoring (Davidson’s 2007, p. 666). The patients complain of having been asleep all night but not refreshed, and multiple breathing pauses (apneas) with bed partners complaining of loud snoring. The diagnoses by investigation require that, once a person complains of daytime sleepiness not resulting from inadequate time in bed or excessive work then a specialist should investigate further for obstructive sleep apnea. The investigation involves quantitative assessment of daytime sleepiness by asking how likely one dozes or falls asleep while; sitting and reading, watching TV, in a theatre, sitting and talking to someone, sitting after lunch, as a passage in a car, and while in a car after stopping for few minutes in traffic (Davidson’s 2007, p. 666). Through overnight studies of breathing to diagnose oxygenation and sleep through overnight oxygen saturation trace. The test involves performing overnight oximetry in patients home to monitor oxygen concentration on the blood. The complexity of this diagnosis varies depending on the probability of diagnoses, resources and differential diagnoses (Davidson’s 2007, p. 667). The threshold for diagnosing apnea syndrome is 15 apneas per hour of sleep where an apnea is a 10-second longer breathing pause. Diagnostic test can be done by use of polysomnography used in a sleep study for recording physiological changes occurring during sleep. Similarly, Electroencephalography (EEG) gets used to monitor neurological changes arising due to the development of obstructive sleep apnea (Hutchinson’s 2007, p. 57). 3.1 Historical development of therapeutics/Medical treatment The historical of therapeutics and medical treatment developed with the development and discovery of the cardio metabolic risk factors. The treatment for obstructive sleep apnea varied depending patient’s medical history, the severity of the obstruction and the cause of the obstruction (Giles 2006, p. 2413). Once the cause of the obstruction got treated then the patient felt relieved. For example, the obstruction caused by lymphoid tissue causing enlargement of tonsils and adenoids in acute mononucleosis may be treated by administering anti-inflammatory steroids. More so, obstructive sleep apnea gets treated by change of life style, for example, refraining from alcohol and exercising regularly. Currently, positive airway pressure is the therapeutic intervention widely used where a controlled stream of air gets pumped by a breathing machine over a mask on the mouth and nose (Giles 2006, p. 2413). 3.2 Current management practices Therapeutic management includes advising the patient to avoid evening alcohol. In most cases, patients use continuous positive airway pressure (CPAP), administered a nasal mask every night (Davidson’s 2007, p. 667). CPAP keeps the throat opened by keeping the upper airway pressure above atmospheric pressure; this pressure gets set in the laboratory at the lowest amount that can prevent apneas. Similarly, patients wear mandible advancement devices within the mouth, which are effective in preventing airway obstruction (Hutchinson’s 2007, p. 393). More so, in mild cases of obstructive sleep apnea patients get advised not to lie on the supine position while sleeping to avoid the falling back of the tongue to the throat (Hutchinson’s 2007, p. 393). The other management is by surgery which gets used to correct oropharynx and nasal passage. Nasal airway passage gets improved by performing septoplasty and turbinate surgery while Uvulopalatopharyngoplasty and tonsillectomy surgery get used to correct pharyngeal obstruction (Williams 2004, p. 708). Other surgical option shrinks the excessive tissue on the throat. Tonsillectomy involves the removal of adenoid tissue to clear the post-nasal obstruction and discharge, (Pinsky 2002.p.1026). 3.2.1 The benefits and limitations of the management methods First is the benefits and limitation of surgical management and treatment methods of sleep apnea. Adenoidectomy is one of the surgical methods used in reduction of obstructive sleep apnea it is beneficial in reduction of obstructive sleep apnea associated with post nasal obstruction it also reduces post nasal discharge which can contribute to the development of obstructive sleep apnea (Davidson’s 2007, p. 667). Adenoidectomy is also beneficial in reduction of obstructive sleep apnea caused by adenoid hypertrophy and rhinosinusitis. In most cases, surgery has proved ineffective complete cure of sleep apnea (Giles 2006, p. 2425). Secondly, are the benefits and limitations of therapeutics management and treatment methods of sleep apnea. Therapeutics managements produce dramatic effects in enhancing improvement of the symptoms of sleep apnea by; first, increasing daytime performance 0f duty because the patient gets enough sleep during sleep hours. Secondly, improves the quality of life and survival by ensuring sufficient flow of oxygen and protecting the obstruction of the airway when one changes life style by avoiding alcohol (Davidson’s 2007, p. 667). CPAP is safe and effective management of the disease because it enhances breathing, maxillomandibular advancement increases oxygen saturation in arterial blood. The limitations are that CPAP therapy is uncomfortable, and many patients decline to use it and that it does not give complete cure to obstructive sleep apnea (Davidson’s 2007, p. 667). 3.3 Development of new therapy Some patients with obstructive sleep apnea managed by continuous positive airway pressure sometimes they develop central sleep apnea, they might also develop complex sleep apnea syndrome (Tasali 2008, p. 218). The development of sleep apnea and the associated complication has led to the invention and development of new therapies. For example, the development of bilevel positive airway pressure, which allows separation between inspiratory and expiratory pressure that makes patient more comfortable (Tasali 2008, p. 219). This device is simple it gets worn in the nostrils, and it does not need electricity or tubing. The use of continuous airway pressure is an effective therapy in management of patients with complex sleep apnea syndrome. Continuous air pressure increases oxygen saturation hence reducing sleep disruption. Therefore, as the discovery of the disease continues with discoveries of related complications so has the management developed. 3.4 Future perspectives related to prediction, prevention and management of the disease. Prediction of obstructive sleep apnea can be done in a person who complains of excessive sleep during day time and their bed partner’s reports episode of snoring during the night (Lorenzi 2007, p. 617). Obstructive sleep apnea can be prevented by reduction of the risk factors. Obesity as one of the risk factor predisposing to obstructive sleep apnea should be prevented, and people should be advised to reduce their weight. People should be advised to sleep on one side since sleeping in the supine position leads to falling back of the tongue causing obstruction of the airway. Prediction gets carried out in respect to the prevalence and risk factor of the disease as it is common among the elderly and men than in the young people and women (Lorenzi 2007, p. 615). Further management in men requires that the causes of the disease be monitored and managed. Therefore, the following get monitored and managed, fat deposition around the parapharyngeal area, lengthening of the soft plate and changes in structures of the areas surrounding the pharynx (Givelber 2005, p. 220). More so, people should avoid alcohol and smoking 4-6 hours before going to bed, they should also avoid sedatives. People with mild obstructive apnea should avoid the predisposing factors. People with moderate to severe obstructive sleep apnea should be investigated further and managed with continuous positive airway pressure. 4.0 Summary and conclusion The above context shows that obstructive sleep apnea is a disorder caused by obstruction of the pharyngeal airway. To preserve pharyngeal airway patency neuromuscular systems increase the activity of genioglossus dilator muscle. The development of hypercapnia and hypoxemia raises respiratory effort leading to arousal from sleep. Obstructive sleep apnea results to complication of other systems such as; the cardiovascular system, central nervous system and endocrine system. Continuous positive pressure is one of the effective methods used in management of obstructive sleep apnea; surgery gets carried out in some cases. Therefore, the treatment of sleep apnea focuses on clearing the airway and ensuring a smooth airflow in the respiratory system. Bibliography: Davidson, S. (2007). Principles of Practice of Medicine 21th edn. New York Oxford, Philadelphia Drager , A Lorenzi et al, 2007. Early Signs of Atherosclerosis in Obstructive Sleep Apnea. Am J Respir Crit Care Med p. 613-8 Carlos L. Rodriguez et al, 2010. Sleep Medicine. 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