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					POLYSOMNOGRAPHIC DIAGNOSES OF PATIENTS REFERRED TO THE SLEEP

              DISORDERS CENTER BY OTOLARYNGOLOGISTS




                       DR. AHMED BAHAMMAM, FRCP, FCCP

 Sleep Disorders Center, Respiratory Unit, Department of Medicine, College of
            Medicine, King Saud University, Riyadh, Saudi Arabia




CORRESPONDING AUTHOR:

DR. AHMED BAHAMMAM
ASSOCIATE PROFESSOR
DIRECTOR, SLEEP DISORDERS CENTER
COLLEGE OF MEDICINE, DEPARTMENT OF MEDICINE 38, KING SAUD UNIVERSITY
Box 2925, Riyadh 11461, Saudi Arabia
Tel: 966-1-467-1521
Fax: 966-1-467-2558
E-mail:      ashammam2@yahoo.com
             ashammam@awalnet.net.sa




                                                                                1
ABSTRACT:



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: Apnea, sleep, otolaryngologists, polysomnography.




                                                                                      2
INTRODUCTION:

       In the otolaryngology literature, the syndrome of “hypersomnia caused by
                                                                          (1)
upper airway obstruction” was introduced 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
                                                             (2)
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 apnea to hypopnea syndrome on the other side. Obstructive

sleep apnea (OSA), the most widely known disorder in the category, affects 2%

to 4% of middle-aged adults (2). 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

of their problem. 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



                                                                                      3
culminating in apnea, affects an estimated 5-86% of men and 2-57% of women in
                                                             (3)
with a mean prevalence of 32% in men and 21% in women          . At the present
                                                                           (4)
time, 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 service 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 how did this population of patients

compare with patients referred by pulmonologists for the same reason.




                                                                                     4
PATIENTS AND METHODS:

       We retrospectively reviewed the polysomnographic records of all patients

referred to the SDC by otolaryngologists in the period between April 2002 and

May 2004.

Study population:

       All patients referred to the sleep disorders centers 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 called the ENT group.

Polysomnography (PSG):

       Sleep studies consisted of an all-night PSG that included four EEG

placements (C1-A4, C2-A3, O1-A4, and O2-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 either 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




                                                                                    5
using Alice® 4 diagnostic equipment from Respironics, inc, 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 sleep time

(TST), time spent during sleep with O2 saturation (O2 sat) less 90%, nadir O2

sat (lowest recorded O2 sat during sleep), desaturation index (the number of

desaturation events/hour of sleep), percentage of snoring time (total snoring

time/TST) and arousal index (5, 6). An apnea was defined as a decrease in peak

inspiratory flow to below 10% of the surrounding baseline for at least 10 seconds.

A hypopnea 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 apnea (OSA) was defined as an

apnea/hypopnea index (AHI) 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 (7). Habitual snoring was defined, as

snoring that does not affect sleep architecture (8). The severity of OSA was

graded based on the AHI (in accordance with the American Academy of Sleep

Medicine) (9) into mild (AHI 5-15 events/hour, moderate (15<AHI<30), and severe

(AHI>30 events/hour).




                                                                                  6
      The ENT group was compared to all patients referred by pulmonologists

(who are 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.




                                                                                  7
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.




                                                                                   8
RESULTS:

      Fifty-eight patients were referred by 19 otolaryngologists from different

institutes for PSGs. That number represents 8% of the total performed PSGs

during the study period. The patients referred by the pulmonologists during the

study period represents 4.3% of the total performed PSGs.

      Table 1 demonstrates the clinical and polysomnographic 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 O2 sat

of 83.5% ± 1.2. Snoring was present in all 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 O2 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 O2 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. 12.5% of the ENT group were

diagnosed to have habitual snoring compared to none in the pulmonary group.

8.9% of ENT group were diagnosed to have RERAs compared to 3.3% in the

pulmonary group. Among the patients referred by the pulmonologists, three were




                                                                                   9
diagnosed to have sleep hypoventilation syndrome and one to have narcolepsy.

Nine (47%) of the otolaryngologists ordered only 1 study. Six (31%) of the 19

otolaryngologists ordered 24 (41%) of the sleep studies.




                                                                                10
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 study and be informed 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 (10). OSA patients with an apnea index (AI) of more than 20

have increased mortality (11). Moreover, otolayngologists should be prepared to

recommend and dispense medical and surgical treatments for this large group of

patients.

       In the present study, otolaryngologists’ referrals represent 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 (4). 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 patient’s 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




                                                                                    11
                                                                                  (12)
distinguish OSA from non-OSA patients. In a study by Hoffstein and Szalai

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 (13). The consensus agreement is to use of nCPAP as
                                                        (14)
the first line treatment for patients with severe OSA      . If the surgical option is

adopted by the patient and the treating 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 post-operative 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 otolaryngologists (19 doctors only) who referred

patients to the SDC have adequate experience and knowledge on how to

clinically recognize patients with suspected OSA.




                                                                                         12
       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 whom major concern is apnea and choking (may indicate

more severe OSA) are likely to visit to the pulmonologists and those whom 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 otolaryngologists 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.




                                                                                       13
REFERENCES:

  1. Simmons FB, Hill MW. Hypersomnia caused by upper airway

     obstructions: a new syndrome in otolaryngology. Ann Otol Rhinol

     Laryngol. 1974; 83: 670-3.

  2. Young T, Palta M, Dempsey J, et al: The occurrence of sleep-disordered

     breathing among middle-aged adults. N Engl J Med 328: 1230-1235,

     1993.

  3. Hoffstein V: Clinical significance and management of snoring without

     obstructive sleep apnea syndrome. In: Breathing Disorders in Sleep

     (chapter 12). McNicholas WT, Phillipson EA (Eds). W.B Saunders,

     London, pp. 164-178, 2002.

  4. Punjabi NM, Welch D, Strohl K. Sleep disorders regional sleep centers: A

     national cooperative study. Sleep 2000; 23: 471-480.

  5. Rechtschaffen A and Kales A (Eds). A Manual of Standardized

     Terminology, Techniques and Scoring System for Sleep Stages of Human

     Subjects. Washington: NIH Publication number 204, US Government

     Printing Office, 1968.

  6. American Sleep Disorders Association, Atlas task Force. EEG arousals:

     Scoring rules and examples. Sleep 1992; 15: 174-184.

  7. Guilleminault C, Stoohs R, Shiomi T, et al. A cause of excessive daytime

     sleepiness: the upper airway resistance syndrome. Chest 1993; 104: 781-

     787.




                                                                             14
8. Epstein MD, Chicoine SA, Hanumara RC. Detection of upper airway

   resistance syndrome using a nasal cannula/pressure transducer. Chest

   2000; 117: 1073-1077.

9. American Academy of Sleep Medicine Task Force. Sleep related

   breathing disorders in adults: recommendation for syndrome definition and

   measurement techniques in clinical research. Sleep 1999; 22: 667-689.

10. Bahammam A, Kryger M. Decision making in obstructive sleep disordered

   breathing: Putting It All Together. Otolaryngol Clin 1999; 32: 333-348.

11. He J, Kryger MH, Zorick FJ, et al: Mortality and apnea index in obstructive

   sleep apnea: Experience in 385 male patients. Chest 94:9-14, 1988.

12. Hoffstein V, Szalai JP. Predictive value of clinical features in diagnosing

   obstructive sleep apnea. Sleep 1993; 16: 118-122.

13. Lévy P, Pépin JL. Management options in obstructive sleep apnea

   syndrome. In: Breathing Disorders in Sleep (chapter 7). McNicholas WT,

   Phillipson EA (Eds). W.B Saunders, London, pp. 105-115, 2002.

14. Loube DI, Gay PC, Strohl KP, Pack AI, White DP, Collop NA. Indications

   for positive airway pressure treatment of adult obstructive sleep apnea

   patients. A consensus Statement. Chest 1999; 115: 863-866.




                                                                                  15
      Table 1: Clinical and polysomnographic characteristics of both groups.



                                       ENT patients    Pulmonary patients
                                                                               p-value
                                         (n = 31)            (n = 58)

Age                                     44.5 ± 1.95         48.7 ± 2.5           NS

BMI (kg/m2)                             32.2 ± 0.96         37.9 ± 2.2          0.03

Neck circumference                      16.4 ± 0.19        16.5 ± 0.37           NS

Males                                   20 (64.5%)         49 (84.5%)            NS

AHI                                     33.9 ± 4.5          47.4 ± 7.1          0.04

Time with O2 sat < 90% (minutes)        13.04 ± 3.7        53.2 ± 10.9         <0.001

Desaturation index                      46.9 ± 16.2         49.6 ± 6.5          0.012

Nadir O2                                83.5 ± 1.2          73.5 ± 2.6         <0.001

Snoring time (% of TST)                 22.2 ± 2.5          19.7 ± 3.7           NS




                                                                               16
FIGURE LEGENDS:




               Figure1: Distribution of the PSG diagnoses across both groups




               50%
  Percentage




               40%

               30%

               20%

               10%

                0%
                     Mild OSA   Moderate   Severe OSA    Habitual    RERAs   Others
                                  OSA                    snoring


                                      ENT patients      Pulmonary patients




                                                                                      17