Pathogenetic role of increased nasal resistance in obese patients with obstructive sleep apnea syndrome.

BACKGROUND: The role of increased nasal resistance in obstructive sleep apnea syndrome (OSAS) remains controversial. The aim of this study was to examine the pathogenetic role of nasal obstruction in obese patients with OSAS. METHODS: Patients with OSAS (n = 125) at a university hospital were divided into three groups according to body mass index (BMI): nonobese (BMI < 25 kg/m(2)), mildly obese (25 kg/m(2) < or = BMI < 30 kg/m(2)), and obese (BMI > or = 30 kg/m(2)). The subjects underwent nasopharyngoscopy, measurement of nasal resistance, and polysomnography. RESULTS: We studied 42 nonobese, 47 mildly obese, and 36 obese patients with OSAS. Among the obese, but not the nonobese and mildly obese patients, we found significant correlations between the oxygen desaturation index (ODI) and bilateral nasal resistance (BNR; r = 0.412; p = 0.013), between the ODI and unilateral higher nasal resistance (UHNR; r = 0.413; p = 0.012), and between the apnea index and UHNR (r = 0.334; p = 0.046). Multiple regression analysis incorporating all patients showed that BMI (p < 0.001) and BNR (p = 0.033) were independently related to the ODI. CONCLUSION: In obese patients with OSAS, increased nasal resistance could play an important pathogenetic role in hypoxemic apnea.

Pharyngeal morphology: a determinant of successful nasal surgery for sleep apnea.

OBJECTIVES/HYPOTHESIS: To estimate the effectiveness of nasal surgery on the occurrence of sleep apnea, and to analyze the pharyngeal morphology of apnea patients whose sleep-disordered breathing was ameliorated postoperatively. STUDY DESIGN: Prospective study. METHODS: Thirty-five consecutive patients with apnea and nasal obstruction underwent polysomnography and a morphological examination of the upper airway before and after nasal surgery, which included septoplasty, inferior turbinectomy, and/or functional endoscopic sinus surgery. RESULTS: Sleep apnea was significantly ameliorated in only eight patients. The postoperative reduction in the apnea-hypopnea index tended to be lower in those with a low-positioned soft palate, reflected in an elevated modified Mallampati score, and a narrow retroglossal space. Neither swollen tonsils nor narrow fauces affected the surgical outcome. Regression analysis showed that the modified Mallampati score (P < .05) and the retroglossal space (P < .05) were significant predictors of postoperative improvement in the apnea-hypopnea index. CONCLUSIONS: Among sleep apnea patients suffering from nasal obstruction, nasal surgery is effective in those with a high-positioned soft palate and/or a wide retroglossal space.

Morphological examination of upper airway in obstructive sleep apnea.

OBJECTIVES: An aim of this study was to assess the predictive power of an otorhinolaryngological examination of the upper airway to identify risk factors of obstructive sleep apnea syndrome (OSAS) in the patients. METHODS: We examined 141 consecutive patients with OSAS. The morphological features were assessed by the designated otorhinolaryngologist while the subjects were sitting relaxedly with tidal breathing. The bilateral nasal resistance was measured using the active anterior rhinomanometry during daytime wakefulness. RESULTS: The body mass index (BMI), fauces's narrowness, neck circumference, lowest oxygen saturation, tonsil size and modified Mallampati grade (MMP) showed the statistically significant correlations with the apnea-hypopnea index (AHI) of an index of apnoeseverity, however, the age, Epworth sleepiness scale (ESS), nasal resistance and retroglossal space were not significantly associated with the AHI. CONCLUSIONS: The upper airway morphology significantly associated with AHI are fauces's narrowness, tonsil size, and MMP, but not nasal resistance and retroglossal space.

Significance of a screening device (Apnomonitor 5) for sleep apnea syndrome.

OBJECTIVES: The objective was to evaluate the significance of a portable sleep-monitoring device (Apnomonitor 5, Chest Co., Tokyo, Japan) to diagnose sleep apnea syndrome (SAS). METHODS: The Apnomonitor 5 comprised an oronasal thermistor, a pulse oximeter, chest and abdominal belts to monitor the circumferences of the chest and abdomen, a microphone to monitor tracheal sound, a position detector, and an integrative unit. This screening device was commercially available and it had been used to diagnose SAS in our country. Twenty-two consecutive adults who attended Inazawa City Hospital who were suspected for SAS were prospectively enrolled and they undertook the standard polysomnography (PSG) and Apnomonitor 5 simultaneously. The designated polysomnographers analyzed the records of the PSG and Apnomonitor 5. These sleep and respiratory parameters of the devices were compared, the results of which were double-checked by the designated sleep specialist. RESULTS: The apnea-hypopnea index (AHI), apnea index, total number of apnea, and oxygen desaturation index obtained by the PSG and Apnomonitor 5 correlated significantly, whereas the averaged sleep time, total number of hypopnea, hypopnea index, and nadir oxygen saturation differed between the devices. The sensitivity of the Apnomonitor 5 versus PSG was 95% in the SAS patients with the AHI> or =15. CONCLUSIONS: The Apnomonitor 5 can be a sensitive and useful screening device for SAS especially in patients with the AHI> or =15.

Daytime polysomnography for early diagnosis and treatment of patients with suspected sleep-disordered breathing.

Excessive daytime sleepiness (EDS) is a common complaint among patients with sleep-disordered breathing (SDB). Population-based studies on traffic and industrial accidents suggest a relationship between EDS and life-threatening events, and adults with EDS have cognitive and memory problems. Nocturnal polysomnography (nPSG) is essential for diagnosing SDB but it is time and energy consuming. We examined the usefulness of daytime polysomnography (dPSG) for the early diagnosis and treatment of patients with suspected SDB. We studied 108 consecutive patients aged 51.9 +/- 13.5 years (mean+/-SD). All patients underwent dPSG and nPSG. The number of apnea/hypopnea episodes per hour (apnea/hypopnea index: AHI) and the number of 3% desaturation episodes per hour (desaturation index: DSI) were calculated. All patients were classified into two groups. The REM group consisted of subjects who had an AHI < or = 25/h, AHI(REM)/AHI(NREM) > 2, and AHI(NREM) < 15/h. Those who did not satisfy these criteria were placed in the NREM group. Continuous positive airway pressure (CPAP) titration was performed for patients whose AHI was > or =20/h on dPSG. Using the international classification of sleep disorders, 96 patients were diagnosed as obstructive sleep apnea [including five upper airway resistance syndrome (UARS) patients], six patients were snoring, four had idiopathic hypersomnia due to a medical condition, and two had circadian rhythm sleep disorders. The sensitivity of dPSG for AHI was 81.0%, specificity was 100%, and accuracy was 83.5%. The sensitivity and accuracy of dPSG for AHI in the REM group were considerably lower than in the NREM group. There was no significant difference for optimal CPAP between dPSG and nPSG. In the five patients with UARS, their AHI, DSI, and arousal index on dPSG were 0.92 +/- 1.2/h, 2.9 +/- 3.4/h, and 29.3 +/- 3.5/h, respectively, and their AHI and DSI on nPSG were 3.2 +/- 2.5/h and 2.8 +/- 2.4/h, respectively. However, their respiratory effort-related arousals were 37.9 +/- 7.4/h, and their arousal index was 33.2 +/- 6.3/h. The five patients with UARS were also treated with CPAP, and their daytime sleepiness was improved. Although dPSG has limitations, these results indicate that dPSG recording is clinically useful for the diagnosis of and determination of types of treatment in patients with suspected SDB.

Obstructive sleep apnoea associated with congenital choanal atresia.

We report here a very rare case of bilateral congenital choanal atresia untreated for the 27 years after birth. A 27-year-old Japanese man complaining of long-term nasal obstruction, snoring and daytime sleepiness visited our hospital. He exhibited the characteristic appearances of long face and bilateral hypoplastic cheeks. Examination by flexible fiberscopy and computed tomography led us to diagnose him with bilateral choanal atresia. Subsequent polysomnography revealed the number of apnoea or hypopnoea episodes per hour (apnoea-hypopnoea index, or AHI) to be over 10. On the basis of these observations, we modified the diagnosis to obstructive sleep apnoea syndrome (OSAS) secondary to congenital choanal atresia.

Nasal resistance for determinant factor of nasal surgery in CPAP failure patients with obstructive sleep apnea syndrome.

OBJECTIVES: Given that criteria for nasal surgery in individuals with obstructive sleep apnea syndrome (OSAS) have not been proposed, we investigated the effectiveness of nasal surgery for CPAP failure in patients with both severe OSAS and nasal obstruction. PATIENTS AND METHODS: Conventional nasal surgery was performed in 12 patients who were refractory to treatment by CPAP. The subject group consisted of 12 males (mean age, 54.2 +/- 9.2 years; range 39-66 years). The effect of nasal surgery was evaluated with data from preoperative and postoperative polysomunography. The nasal resistance value was first deduced to determine which OSAS patients with CPAP failure should undergo nasal surgery, compared to control values. RESULTS: Nasal surgery resulted in a significant decrease in nasal resistance, as measured by rhinomanometry, from 0.57 +/- 0.31 Pa/cm3 /sec to 0.16 +/- 0.03 Pa/cm3/sec and rendered all patients tolerant to CPAP. In addition, the lowest nocturnal oxygen saturation significantly increased from 68.3 +/- 12.1% to 75.3 +/- 7.1% after surgery. Subjectively, Epworth sleepiness scale (ESS) significantly decreased from 11.7 +/- 4.1 to 3.3 +/- 1.3 after surgery, but the number of apnea and hypopnea episodes per hour did not change significantly. In five patients, for whom it was possible to perform a CPAP titration before nasal surgery, the value decreased significantly from 16.8 +/- 1.1 to 12.0 +/- 1.9 cmH2O. The bilateral nasal resistance of the 410SAS patients with CPAP therapy (control group) was 0.24 +/- 0.11 Pa/cm3/sec. The cut off value for differentiation between CPAP failure patients and control group was determined as 0.38 Pa/cm3 /sec. CONCLUSION: Increased nasal resistance is a determinant of CPAP failure, and the surgical correction of severe nasal obstruction should thus be considered to facilitate treatment of OSAS patients with CPAP.