Kiyokazu Hasegawa

Endoscopic examination of obstructive sleep apnea syndrome patients during drug-induced sleep.

Sixty patients diagnosed with obstructive sleep apnea syndrome (OSAS) underwent uvulopalatopharyngoplasty (UPPP). The effects of surgery were studied based on endoscopic findings during drug-induced sleep and determination of the apnea-hypopnea index (AHI) before and after the operation. Changes in the form of the airway during sleep in the recumbent position were observed, and the role of upper airway endoscopy in the diagnosis and surgical treatment of OSAS was determined. The site of airway obstruction during sleep induced by i.v. injection of 10 mg of diazepam was classified into five types, and changes in AHI and the site of airway obstruction were compared before and after surgery. Changes in airway morphology during sleep in the supine and recumbent positions were also compared before surgery. The postoperative improvement rate was 74.4% for the soft palatal type of obstruction, 76.2% for the tonsillar type, 53.3% for the circumferential palatal type and 34.0% for the mixed type. Treatment produced excellent or good effects for the soft palatal and tonsillar types of obstruction. However, many patients with the circumferential palatal and mixed types of obstruction showed only some improvement or no change. Good airway morphology was maintained in the recumbent position by patients with the soft palatal type of obstruction. With the circumferential palatal and mixed types of obstruction, improvement can be expected from operations which include surgical treatment of the posterior pharyngeal wall or lateral funiculus, or with midline laser glossectomy. A good operative outcome can be predicted in patients showing improvement of apnea in the recumbent position preoperatively.

Influence of sleep respiratory disturbance on nocturnal blood pressure.

We subjected 65 patients to overnight monitoring and continuous nocturnal blood pressure measurement in order to assess the influence of sleep apnea on the circulatory system. Thirty-one patients were compared before and after surgery. The severity of sleep apnea was classified by means of the apnea-hypopnea index (AHI), the duration of exposure to low-level oxygen [calculated as the desaturation time (DT)] and changes in blood pressure (BP). Before surgery, a significant correlation was noted between DT and changes in BP. Therefore, DT was considered useful for assessing the influence of sleep apnea on nocturnal BP. After surgery, an improvement in AHI of > 50% was noted in 19/31 patients (61.3%), a result comparable to that described in the literature. Improvements in DT and change in BP were > 50% in 21/31 (67.7%) and 14/ 31 (45.2%) patients, respectively. With regard to the severity of sleep apnea before surgery, AHI was > or = 50 and DT > or = 40% in 10 and 18 patients, respectively and 19 patients showed changes in BP of > or = 40 mmHg. After surgery, one, five and two patients, respectively, still showed these values. Thus, a beneficial effect of surgery was demonstrated.

Dynamic MRI diagnosis of sleep-disordered breathing.

According to the obstructive site, the different types of obstructive-type sleep-disordered breathing are classified as the soft palate type, palatine tonsil type, soft palate and depressed lingual root type, depressed lingual root type and epiglottis type. In this study, we conducted dynamic MRI examinations of the oral, pharyngeal and lingual root sites in patients with obstructive sleep-disordered breathing, and studied the usefulness of MRI as a diagnostic tool for the examination of such obstructive sites.