 examination that facilitates screening of patients possibly affected by the disease or prediction of its severity.
The purpose of this study was to validate the clinical usefulness of easy-to-assess clinical signs such as the Friedman tongue position (FTP), uvula size, and certain complementary examinations whose importance has not been clearly established, and to explore their potential value as predictors of the AHI.
Patients who were naïve for sleep studies were referred to the sleep laboratory for diagnosis and treatment of OSAS. Clinical suspicion of OSAS was established on the basis of snoring and daytime sleepiness recorded during the clinical interview with the Spanish version of the Epworth Sleepiness Scale.8 Patients with snoring history and clinical suspicion of OSAS entered the study protocol.
For inclusion, an individual had to be an adult patient (>18 years) referred to our Institution to diagnose or rule out OSAS. Exclusion criteria included (1) having other respiratory diseases, (2) having undergone a tracheostomy, (3) having a clinical suspicion of other sleep disorders, (4) having other comorbidities (chronic renal, cardiac, or hepatic failure), (5) having active neoplasms, or (6) refusal to follow the study protocol of our sleep disorders unit.
We divided patients into 4 groups: group 1 comprised individuals without OSAS; group 2, patients with mild OSAS; group 3, patients with moderate OSAS; and group 4, patients with severe OSAS. We planned to have a minimum of 30 patients in the smallest FTP group. We considered that many of the patients referred to our sleep laboratory would present some degree of sleep apnea; only a minority were expected to be snorers without sleep disorder (<10%). We also estimated a loss to follow-up of 10%. In view of our past experience, we expected the frequency of sleep apnea to be 3 times higher in groups 2 and 3 than in groups 1 and 4; we therefore aimed to include a minimum of 268 patients.
This was a single-center, observational, cross-sectional study performed at the sleep disorders unit of a community hospital (Esperit Sant de Santa Coloma, Barcelona, Spain) with a reference area of 150 000 inhabitants. The study's primary aims were (1) to determine the relationship between AHI values and potential explanatory variables (sex, age, body mass index [BMI; calculated as weight in kilograms divided by height in meters squared], cervical perimeter, nasal flow [measured in decimeters cubed per second (dm3/s) at 150 Pa, hereinafter FL150], FTP, tonsil, and uvula scores); and (2) to investigate the role of these variables as predictors of the AHI. The secondary aim was to determine a predictive model to establish the diagnosis and severity of OSAS.
The following examinations were performed in all patients during the first visit: (1) BMI determination, (2) neck perimeter measurement, (3) oropharyngeal examination, (4) fiberendoscopy, (5) phinomanometry, and (6) a sleep study.
At entry, after external physical examination, the otorhinolaryngologist (X.B.) conducted the oropharyngeal examination and the rhinopharyngolaryngoscopy or nasal fibroscopy. The oropharyngeal examination was performed by the same physician in all cases using a frontal light to establish the FTP (Figure 1) and tonsil size (TS) score (Figure 2) using Friedman's criteria9 with the patient seated. We added a uvula score predesigned for this study according to the following criteria:
Rhinomanometry was then performed the day before the sleep study. The fiberendoscopy was performed with a Rhino-Laryngo fiberscope (model ENF-GP; Olympus Co, Tokyo, Japan) and the rhinomanometry with a Sibelmed Rhinospir pro (Sibel S.A., Barcelona, Spain) in accordance with international guidelines.10 The sleep study was performed using a previously validated portable respiratory recording device (PRRD)11 (Sibel home Plus; Sibel S.A.). The system records oronasal airflow by thermistor; nasal airflow via a nasal cannula, which acts as pressure transducer; chest and abdominal respiratory movements; tracheal sounds; heart rate; oxyg