|Year : 2004 | Volume
| Issue : 2 | Page : 74-78
Polysomnographic diagnosis of patients referred to the sleep disorders center by otolaryngologists
Sleep Disorders Center, Respiratory Unit, Department of Medicine, College of Medicine King Saud University, Riyadh, Saudi Arabia
|Date of Web Publication||12-Jul-2020|
FRCP, FCCP Ahmed Bahammam
Sleep Disorders Center, Respiratory Unit, Department of Medicine, College of Medicine King Saud University, Riyadh
Source of Support: None, Conflict of Interest: None
Objectives: To determine the polysomnographic diagnoses of patients referred by otolaryngologists for overnight sleep studies and the accuracy of their clinical diagnoses.
Methods: We retrospectively reviewed the polysomnographic records of all patients referred to the sleep disorders center (SDC) by otolaryngologists with the clinical suspicion of obstructive sleep apnea (OSA). The studied group was compared to all patients referred by pulmonologists with the clinical suspicion of OSA, for overnight sleep studies within the same period.
Results: Fifty-eighty patients were referred by otolaryngologists and 31 by pulmonologists. Otolaryngologist’s referrals represented 8% of the total referrals to the SDC during the study period. Patients referred by pulmonologists had more severe OSA compared to patients referred by otolaryngologists.
Conclusions: Relatively small number of patients with the clinical suspicion of OSA were referred by otolaryngologists to the SDC. Future studies are needed to assess the knowledge and attitudes of otolaryngologists toward OSA and the importance of performing PSG for patients with suspected OSA.
Keywords: Apnoea, sleep, otolaryngologists, polysomnography
|How to cite this article:|
Bahammam A. Polysomnographic diagnosis of patients referred to the sleep disorders center by otolaryngologists. Saudi J Otorhinolaryngol Head Neck Surg 2004;6:74-8
|How to cite this URL:|
Bahammam A. Polysomnographic diagnosis of patients referred to the sleep disorders center by otolaryngologists. Saudi J Otorhinolaryngol Head Neck Surg [serial online] 2004 [cited 2022 Nov 30];6:74-8. Available from: https://www.sjohns.org/text.asp?2004/6/2/74/289587
| Introduction|| |
The syndrome of “hypersomnia caused by upper airway obstruction” was introduced to the otolaryngology literature by Simmons and Hill in 1974 . Since then, the interest of the otolaryngologists in this field of medicine has increased and many surgical procedures have been introduced to try to reconstruct the upper airway or bypass it to provide cure. Obstructive sleep-disordered breathing (OSDB) is a relatively common medical problem . It consists of a spectrum ranging from habitual snoring on one side to the respiratory effort related arousals (RERAs) (called previously the upper airway resistance syndrome) and apnoea to hypopnoea syndrome on the other side. Obstructive sleep apnoea (OSA), the most widely known disorder in the category, affects 2% to 4% of middle-aged adults . OSDB diagnosis and treatment crosses many specialty lines. Typically, patients suffering from these disorders will be seen by pulmonologists, neurologists, oral surgeons, dentists, as well as otolaryngologists-head and neck surgeons in their search for diagnosis and cure. From the medical point of view, the management of OSDB can be looked at as a team approach involving more than one specialty.
Why is there so much attention given to these problems? One answer is because it is a newly discovered disease process and we are still trying to explore the causes, complications and effective treatment measures. The other reason is the high prevalence of these disorders in the general population. Snoring itself, which is a common presentation in the otolaryngologist’s practice and thought to be the initial presentation of the spectrum of the disease process culminating in apnoea, affects an estimated 5-86% of men and 2-57% of women in with a mean prevalence of 32% in men and 21% in women . At present, OSA is the most common disorder diagnosed in sleep laboratories .
Good proportion of patients referred to the sleep disorders center (SDC) for sleep studies are usually referred from the otolaryngology services to rule out OSA. To our knowledge, no previous published studies have explored the polysomnographic diagnoses of patients referred to the SDC by otolaryngologists.
We carried out this study to determine the polysomnographic diagnoses of patients referred by otolaryngologists for overnight sleep studies, the accuracy of their clinical diagnoses, and determine the outcome of this population of patients as compared with patients referred by pulmonologists for the same reason.
| Patients and Methods|| |
We retrospectively reviewed the polysomnographic records of alt patients referred to the SDC by otolaryngologists in the period April 2002 to May 2004.
| Study Population:|| |
All patients referred to the sleep disorders center at King Khalid University Hospital (KKUH) and Specialized Medical Center Hospital (SMCH) by otolaryngologists for overnight sleep studies with the clinical suspicion of OSA were included in the analysis. The studied group consisted of 58 patients. This group will be called the ENT group.
| Polysomnography (PSG):|| |
Sleep studies consisted of an all-night PSG that included four EEG placements (C1-A4, C2-A3, 01-A4, and 02-A3); muscle tone and leg movements by chin and leg EMG; eye movements by EOG; heart rate by EKG; oxygen saturation by finger pulse oximeter; chest and abdominal wall movements by thoracic and abdominal belts; air flow by thermistor and nasal prong pressure (NPP); sleep position by position sensor; and snoring by microphone. The PSGs were complete cither as a baseline (monitored for the entire night) or as a split study. For a split study, a minimum of 2 hours of sleep was recorded. If OSA was documented during this time, nasal continuous positive airway pressure (nCPAP) was titrated during the remained time of the study. Twenty-eight (48%) of the 58 studies were performed as split studies. PSG recording was done using Alices 4 diagnostic equipment from Respironics, fnc, Murrysville, Pennsylvania, USA.
| Analysis and Scoring of PSG Data|| |
Page-by-page analysis and scoring of the electronic raw data was done manually by the author to determine total time in bed (TIB), total steep time (TST), time spent during sleep with 02 saturation (02 sat) less 90%, nadir 02 sat (lowest recorded 02 sat during sleep), desaturation index (the number of desaturation events/hour of sleep), percentage of snoring time (total snoring time/TST) and arousal index ,. An apnoea was defined as a decrease in peak inspiratory flow to below 10% of the surrounding baseline for at least 10 seconds. A hypopnoea was defined as any visually appreciable decrease in flow amplitude for two or more consecutive breaths followed by arousal or oxygen desaturation of at least 3%. Obstructive sleep apnoea (OSA) was defined as an apnoea/hypopnoea index (AH1) of (5/hour of sleep. However, for a split study, an AHi of 15 was required to initiate therapy with nCPAP. Respiratory effort related arousals (RERAs) were defined as AHI < 10, frequent EEG arousals in association with flow-limited respiration determined by NPP, excessive daytime sleepiness and no other sleep abnormality . Habitual snoring was defined, as snoring that does not affect sleep architecture . The severity of OSA was graded based on the AHI (in accordance with the American Academy of Sleep Medicine)  into mild (AHI 5-15 events/hour, moderate (15 < AHI < 30), and severe (AHI > 30 events/hour).
The ENT group was compared to all patients referred by pulmonologists (who were not specialized in sleep medicine) with the clinical suspicion of OSA, for overnight sleep studies during the same period. This group will be called the pulmonary group. The pulmonary group was used only for comparison with our studied group with regard to age, body mass index (BMI), PSG diagnosis, AHI, and nadir oxygen saturation. This group consisted of 31 patients.
| Statistical Analysis:|| |
Data are expressed in the text and tables as mean ± standard error of the means (SEM) values. For continuous variable, t-test was used if the distribution was normal. When normality test failed, Mann-Whitney rank sum test was used. The chi- square test was used for comparison of proportions. Results were considered statistically significant at the p = 0.05 level. Standard statistical software (Sigma Stat, version 3; SPSS Chicago, Illinois, USA) was used for the analyses.
| Results:|| |
Fifty-eight patients were referred by 19 otolaryngologists from different institutes for PSGs. This represents 8% of the total performed PSGs during the study period. The patients referred by the pulmonologists during the study period represented 4.3% of the total PSGs performed.
Table 1 demonstrates the clinical and polysomnography features of both ENT and pulmonary groups. Patients in the ENT group were middle aged (44.5 ± 1.95) and overweight (BMI, 32.2 ± 0.96). The 58 patients had quite significant OSA with AHI of 33.9 ± 4.5, desaturation index of 46.9 ± 16.2, and a nadir 02 sat of 83.5% ± 1.2, Snoring was present in al! referred patients. The mean age, gender distribution, neck circumference and snoring time were not statistically different from those of the patients referred by pulmonologists. However, patients referred by the pulmonologists were more obese (BMI; 37.9 ± 2.2 versus 32.2 ± 0.96, p=0.03), and had more severe OSA as indicated by the higher AHI (47.4 ± 7.1 versus 33.9 ± 4.5, p=0.04), longer time with 02 sat <90% (13.04 ± 3.7 minutes versus 53.2 ± 10.9 minutes, p<0.001), higher desaturation index of 49.6 ± 6.5 (p=0.012), and lower nadir 02 of (73.5 ± 2.6 versus 83.5% ± 1.2, p<0.001).
[Figure 1] represents the distribution of the PSG diagnoses across both groups. Fifty-nine percent of the patients referred by otolaryngologists were diagnosed to have moderate to severe OSA. Habitual snoring was diagnosed in 12.5% of the the ENT group as compared to none in the pulmonai7 group. Eight point nine percent of the ENT group were diagnosed to have RERAs compared to 3.3% in the pulmonary group. Among the patients referred by the pulmonologists, three were diagnosed to have sleep hypoventilation syndrome and one to have narcolepsy. Nine (47%), of the otolaryngologists ordered only I study. Six (31%), of the 19 otolaryngologists ordered 24 (41 %) of the sleep studies.
| Discussion|| |
Otolaryngologists have a special interest and expertise in certain conditions associated with OSDB, particularly snoring and mild OSA. As otolaryngologists increasingly serve as the entry point for patients with OSDB, they need to be aware of this condition when taking a history and conducting a physical examination. They need to be knowledgeable about the full spectrum of OSDB and its serious complications. OSDB is a very serious medical problem if left untreated. It is well documented that OSA is associated with and can aggravate many medical illnesses: It is associated with systemic hypertension, pulmonary hypertension, cardiac arrhythmia, ischemic heart disease and stroke . OSA patients with an apnoea index (AI) of more than 20 have increased mortality . Moreover, otolaryngologists should be prepared to recommend and dispense medical and surgical treatments for this large group of patients. In the present study, otolaryngologists’ referrals represented 8% only of the total referrals to the SDC. A national study in the United States revealed that otolaryngologists! referrals represent up to 14% of the total referrals , This finding has few possible explanations: (1) some of the otolaryngologists may not be aware of the importance of PSG to confirm the diagnosis of suspected OSA and assess its severity to tailor treatment to the patientis needs; (2) some may feel that their clinical assessment is enough to assess the severity of the illness, (3) or there is lack of communication between otolaryngologists and sleep specialists. Expert clinical assessment alone has inadequate power to distinguish OSA from non-OSA patients. In a study by Hoffstein and Sza!ai,1993,  evaluating patients’ population with high probability of OSA, an expert health care provider subjective impression, based on history and physical examination alone, correctly identified only approximately 50% of OSA patients. Assessing the severity of OSDB is very important before attempting any treatment modality. Moreover, the goal of treatment should be clear to both, the patient and his/her treating doctor (is the aim of surgery the elimination of snoring or treating OSA). Upper airway surgery (e.g. UPPP) can be considered for patients with habitual snoring or mild OSA. However, the data addressing the role of upper airway surgery in moderate and severe OSA and RERAs lack objective data supporting improvement post-surgery , The consensus agreement is to use nCPAP as the first line treatment for patients with severe OSA . If the surgical option is adopted, by the patient the surgeon in patients with OSA, pre-surgical PSG is important to assess the severity of the condition and the degree of desaturation to plan the short-term postoperative care. Therefore, performing PSG is essential before attempting surgery in patients with clinical suspicion of OSA.
In this study, about 59% of the patients referred by otolaryngologists were diagnosed to have moderate to severe OSA. This good percentage indicates that, this limited number of otolatyngologists (19 doctors only) who referred patients to the SDC have adequate experience and knowledge on how to clinically recognize patients with suspected OSA.
Patients who were referred by pulmonologists in general had more severe OSA compared to those referred by otolaryngologists. None of the patients referred by the pulmonologists were diagnosed to have habitual snoring. It seems that patients whose major concern is apnoea and choking (may indicate more severe OSA) are likely to visit to the pulmonologists and those whose major concern is snoring and throat symptoms visit the otolaryngologists.
In summary, the study shows that relatively small number of patients with the clinical suspicion of OSDB are referred by otolatyngologists to the SDC. The referring otolaryngologists did recognize patients with prominent symptoms of OSA. However, it seems that only small percentage of their patients panel were referred, which suggests that the condition is still underdiagnosed or the otolaryngologists do not value the importance of performing PSG. This seems particularly true as a small group of otolaryngologists ordered most of the studies. Future studies are needed to assess the knowledge and attitudes of otolaryngologists toward OSDB and their perception toward the importance of performing PSG for patients with suspected OSDB. As otolaryngologists play increasingly important roles in the evaluation and treatment of patients with OSDB, it is important that all practitioners systematically study the field of sleep medicine. Special focus should be directed to doctors in training.
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