SHORT COMMUNICATION

OBSTRUCTIVE SLEEP APNEA SYNDROME

Bharat Jain, Director Sleep Laboratory, West Mooreland Country Hospital, Green Berg (P.A.), U.S.A.

Obstructive sleep apnea syndrome (OSAS) is a common disorder that effects, up to 2-4% of the adult population and in particular the older obese males (1). It is characterized by sleep associated- repetitive obstruction of the upper airway that may occur as often as once a minute and can last 1-200 seconds. These obstructive events are usually terminated by transient (5-10 seconds) arousals that are documented by an electroencephalogram. This disruption of sleep architecture results in excessive daytime somnolence (EDS) which is frequently the presenting complaint. Patients with OSAS have a higher mortality, not only from EDS-related accidents, but also from such cardiopulmonary complications as systemic and pulmonary hypertension, congestive heart failure and cerebrovascular accidents. Although the pathophysiology of this syndrome remains to be fully worked out, it is believed that these obstructive events of the upper airway are a result of an interaction between the sleep- associated reduction in upper airway motor tone and the subtle anatomic substrate of upper airway narrowing (2).

The patients with OSAS, in addition to often being unaware of their breathing problem, frequently overlook such symptoms as EDS, snoring, early morning headache, easy fatiguability and poor concentration. It is therefore important to obtain from the bed partner such crucial information as snoring, history of quitting breathing and episodes of restlessness while the patient is asleep. Approximately 80% of the patients diagnosed with OSAS are obese. The oropharyngeal exams of these patients usually reveals evidence for narrowed upper airway with a prominent uvula and soft palate. These patients may also have evidence for retrognathia or a thick, short neck. The predictive value of history and physical examination for OSAS is however low, and a nocturnal polysomnography should be performed to confirm the diagnosis whenever it is suspected. During an overnight polysomnography, the patients

are monitored for various physiological parameters that include electroencephalogram, electroculogram, oro-nasal air flow, chin electromyogram, electrocardiogram, chest wall and abdominal movement, oximetry and leg movements. These records are then scored using standard criteria and the frequency of abnormal breathing events (apneic and hypopneic events) are quantified, The patients are diagnosed with OSAS if the number of apneic and hypopneic events per hour (apnea/hypopnea index) are greater than 5.

Once diagnosed, it becomes imperative to treat OSAS. While treating OSAS patients with an apnea/hypopnea index greater than 20 has been demonstrated to decrease the mortality, one should consider treating OSAS patients with an apnea/hypopnea index between 5 and 20, if they either have underlying cardiopulmonary dysfunction or demonstrate oxygen desaturation less than 85% or have complaints of EDS. Continuous positive airway pressure (CPAP), administered via a nasal mask (3), is currently the treatment of choice for OSAS and has been shown to be effective as long as the patient continues to use it while sleeping. Although very effective in controlling OSAS, the use of the CPAP mask can be inconvenient and bothersome for some patients. By monitoring true compliance (measuring the time that pressure is at the effective level), we have learned that patients are considerably less compliant than they claim to be (4). Moreover 50% of patients stop using CPAP after 2 years.

Surgical measures (Table I) should be considered only after medical therapy has been attempted and failed or when a patient is likely to be non- complaint. Various surgical procedures have been developed to resolve OSAS with the primary goal being cure. Because there are usually multiple regions of anatomic obstruction, surgical intervention may take place at various levels. Nasal reconstruction should be considered for any

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Obstructive Sleep Apnea Syndrome--Bharat Jain

patient with nasal obstruction (e.g. deviated nasal septum, enlarged turbinated etc.) UvulopaJatopharyngoplasty (UPPP) is currently the most Do'2ular surgical procedure for OSAS, and involves removal of redundant tissues at the pharyngeal level. Most studies have however shown about a 50% response rate (5-7) and the survival has not been shown to be improved in patients who underwent UPPP, compared with those who were not treated (8). Much more invasive surgical procedures such as (1) a limited mandibular osteotomy with genioglossus advancement and hyoid suspension; (2) a bimaxillary surgical procedure for advancement of the upper maxilla and mandible and (3) base of tongue surgery, should be attempted only when nasal reconstructive surgery and UPPP have failed to cure OSAS, suggesting that the airway obstruction is occurring at the level of the hypopharynx. Tracheostomy, the first surgical method used to treat OSAS (9), is rarely indicated at this time and should be reserved for those patients who are either severely ill or are refractory to the other modes of therapy.

Drug therapy for OSAS has also been attempted although the results so far have been disappointing. Two approaches to treat OSAS have been tried one approach has been to use respiratory stimulants such as medroxyprogesterone (10,11), almitrine (12), acetazolamide (13) and theophylline (14,15). Although these agents have had little impact on the sleep-disordered breathing, there has been some suggestion that they cause respiratory stimulation in those patients with obesity hypoventilation syndrome who in addition, have a chronic state of hypercapnia (this represents the minority of patients with OSAS). The other approach has been to use drugs that suppress rapid eye movement (REM) sleep, since during this

stage of sleep, the most severe abnormal breathing events tend to occur. Although protryptine, a tricyclic antidepressant that suppresses REM sleep, produces some benefit in the symptomatic treatment of the hypersomnolence of this disease, it has not been conclusively shown to reduce the obstructive events (16,17). There is animal data however, that suggests that this drug has a selective stimulant effect on the upper airway musculature which would be predicted to benefit a patient with OSAS. In any case, most male patients are unable to tolerate the doses of protriptyline that are suggested for optimal effect on the apneas due to its considerable anticholinergic and antihistaminic side effects (16). These studies illustrate that no universally effective agent has yet been identified that will resolve the apneas, hypoxemia and symptoms without significant adverse effects. Drug therapy should however be considered in patients in whom CPAP therapy or surgical correction is contra-indicated. Whatever modality of treatment is undertaken the treatment of OSAS should also include correction of associated medical conditions such as obesity, hypothyroidism and tonsillar hypertrophy. In addition, these patients should be asked to avoid CNS depressants that includes alcohol consumption, since these medications are likely to worsen OSAS. In conclusion, OSAS is a common, yet frequently underdiagnosed syndrome that is associated not only with increased morbidity and mortality but also with socioeconomic consequences from decreased productivity and accidents. An attempt should therefore be made to increase the awareness not only amongst the public but also amongst the physicians. In addition, the management of OSAS is complex and a multidisciplinary approach that includes the fields of medicine and surgery is frequently required.

R e f e r e n c e s

1. Young, T., Palta M., Dempsey J. et al. (1993) : The occurrence of sleep disordered breathing among middle-aged adults. N Eng J Med; 328 : 1230-1235.

2. Sullivan, (3. E. and Issa, F. G. (1985) : Obstructive Sleep Apnea. (31in Chest Med, : 6 : 633-650. 3. Sullivan, C. E., Issa, F.G., Berthon-Jones, M. et al. (1981) : Reversal of obstructive sleep apnea

by continuous positive airway pressure applied through the nares. Lancet 1 : 8 6 2 - 8 6 5 . 4. Kribbs, N. B., Pack A. I., Kline L. R. et al. (1993) : Objective measurement of patterns of nasal

CPAP use by patients with obstructive sleep apnea. Am Rev Resp Dis, 147 : 887-895. 5. Fujita, S., Conway, W., Zorick, F. et al. (1981) : Uvulopalatopharyngoplasty. Otolaryngol Head

Neck Surg, 89 : 923-934.

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Obstructive Sleep Apnea Syndrome--Bharat Jain

6. Fujita, S., Conway, W. et al. (1985) : Evaluation of the effectiveness of uvulopalatopharyngoplasty. Laryngoscope, 95 : 70-74.

7. Simmons, F. B., Guilleminault, C., Miles, L. E. (1984) : The palatopharyngoplasty operation for snoring and sleep apnea. An interim report. Otolaryngol Head Neck Surg, 92 : 375-380.

8. He, J., Kryger, M. H., Zorick, F. J., et al. (1988) : Mortality and apnea index in obstructive sleep apnea : Experience in 385 male patients. Chest, 94 : 9-14.

9. Coccagnia, G., Mantovani, M., Brignani, R. et al. (1972) : Tracheostomy in hypersomnia with periodic breathing. Bull Eur Physiopathol Respir, 8 : 1217-1227.

10. Dolly, F. R. and Block, A. J. (1983) : Medroxyprogesterone acetate and COPD : effect on breathing and oxygenation in sleeping and awake patients. Chest; 84 : 294-398.

11. Sutton, F. D., Zwillich C.W., Creagh C. E. et al. (1975) : Progesterone for outpatient treatment of Pickwickian syndrome. Ann Internal Med, 83 : 476-479.

12. Kreiger, J., Mangin P., Kurtz, F. (1982) : Effects of a ventilatory stimulant, almitrene bismesylate in the sleep apnea syndrome. Curr Ther Res, 32 : 697-705.

13. Shore, E .T. and Millman, R. P. (1983) : Central sleep and acetazolamide therapy. Arch Intern Med 143 : 1278.

14. Mayer, J., Fuchs, E., Hugens, M. et al. (1984) : Long term theophylline therapy of sleep apnea syndrome. Am Rev Resp Dis (Suppl), 129 : A52. (abstract)

15. Guilleminault, C. and Hayes, B. (1983) : Naloxone, theophylline, bromocriptine in obstructive sleep apnea, negative results. Bull Eur Physipathol Respir 19 : 632-634.

16. Clark, R.W., Schmidt, H. S., Schaal, S. F. et al. (1979) : Sleep apnea treatment with protriptyline. Neurology 29 : 1287-1292.

17. Brownell, L. G., West, P., Sweatman, P. et al. (1982) : Protriptyline in obstructive sleep apnea : a double blind trial. N. Engl. J Med, 307 : 1037-1042.

IV East Zonal Conference The 4th East Zonal Conference of the Association of Otolaryngologists of India comprising of members from Bihar, Orissa and West Bengal was held on 30th Nov and 1st December at Dhanbad (Bihar). Dr. J. P. Mukherjee was the Organising Secretary. The guest speakers were Dr. A. Mahadevaiah of Bangalore and Dr. A. N Sinha of Patna. The Conference was attended by a very large number of delegates. The scientific fare dished out was very educative for all participants. In addition to there were 2 panel discussions on otosclerosis and vertigo. There were a large number of free papers and a quiz competition. The award for the best free papers was obtained by Dr. Anirban Biswas of Calcutta. The trophy for the quiz competition was awarded to Drs. D. P. Parekh and Sumanta Dutta from Calcutta.

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