Optimal continuous positive airway pressure in patients with obstructive sleep apnoea: role of craniofacial structure.

Although nasal continuous positive airway pressure (CPAP) is effective in improving nocturnal obstructive apnoea, daytime sleepiness and well-being in patients with obstructive sleep apnoea syndrome (OSAS), not all patients tolerate this treatment. Since optimal CPAP titration is essential to maintain compliance, it is important to elucidate the factors that help to determine the optimal pressure. However, the determinants of the optimal CPAP level are controversial. The subjects comprised 27 Japanese male patients with OSAS who underwent standard polysomnography (PSG), pulmonary function tests, arterial blood gas analysis, cephalometry and CPAP titration. Twenty normal controls also underwent cephalometric analysis. The apnoea-hypopnoea index (AHI), mean oxygen saturation (mean SaO2) and the lowest SaO2 during sleep were found to be 54.7+/-22.6, 89.0+/-5.6%, and 69.7+/-9.0%, respectively by PSG. The mean optimal CPAP was 9.6+/-1.8 cmH2O. The cephalometric angles (SNA, SNB and NSBa) were similar to those found in the control subjects. but MP-H, and PNS-P were significantly longer than those in the control subjects as shown by cephalometry. The optimal CPAP was correlated with the mean SaO2 (P<0.0001), neck circumference (P<0.05) and three cephalometric variables (NSBa: P<0.01, MP-H: P<0.05, PNS-P: P<0.05). Multiple, step-wise, regression analysis showed that the mean SaO2 and NSBa were independent variables that best predicted the optimal CPAP. These variables accounted for 57.5% of the total variance (R2=0.575, P<0.001). Optimal CPAP was closely correlated with oxygen desaturation during sleep. However, the craniofacial structure had additional effects such as an independent factor in determining the optimal CPAP level.

Craniofacial abnormalities in Japanese patients with severe obstructive sleep apnoea syndrome.

OBJECTIVE: To clarify that factors besides obesity play an important role in the development of obstructive sleep apnoea syndrome (OSAS) in Japanese patients, we compared craniofacial structures in patients with severe OSAS with those of normal controls. METHODOLOGY: The craniofacial structures of 60 Japanese patients with severe OSAS and 30 normal controls were evaluated using standard cephalometric analysis. Patients were stratified according to body mass index (BMI): non-obese, BMI < 25; moderately obese, BMI = 25-30, severely obese, BMI > 30. RESULTS: The SNA (sella to nasion to subspinale angle) was significantly smaller in the patient groups than in the controls. The SNB (sella to nasion to supramentale angle) and NSBa (cranial base flexure) were significantly smaller in the non-obese and moderately obese patients than in controls. The MP-H (distance from the mandibular plane to the hyoid bone) and the PNS-P (distance from the posterior nasal spine to the tip of the soft palate) were significantly longer in the patient groups than in the controls. The PNS-P was significantly longer in the severely obese patients than in the non-obese patients. CONCLUSIONS: Japanese patients with severe OSAS have enlargement of the soft tissues and palate as well as craniofacial bony structural abnormalities. This is particularly apparent in non-obese patients.

[A case of intrathoracic extension of retroperitoneal fibrosis].

A 70-year-old man was diagnosed as having retroperitoneal fibrosis 12 years ago. The patient was admitted to our hospital with complaints of fever and left chest pain. On admission, chest radiography revealed left pleural effusion and left pleural thickening. Percutaneous pleural biopsy was performed, and the pleural tissue gave a chronic inflammatory reaction characterized by proliferation of collagen fibers and chronic inflammatory cellular infiltration. Since the retroperitoneal fibrosis had been diagnosed in similar tissue, it was considered that this condition had extended to the pleura. On administration of prednisolone, the intrathoracic lesions and clinical symptoms were improved, but the patient later died of pneumonia. Autopsy showed fibrous pleuritis and chronic fibrosing lung disease. This was an extremely rare case. Prednisolone appears to be useful in the treatment of intrathoracic extension of retroperitoneal fibrosis.

[A case of tuberculous aneurysm of the aorta].

We reported a rare case of tuberculous aneurysm of the aorta managed successfully with urgent surgical therapy. A 35-year-old woman was admitted to our hospital complaining of fatigue and hemoptysis. Laboratory tests showed severe anemia, slight liver dysfunction, elevated level of C-reactive protein, and negative syphilis serologies. The chest roentgenogram revealed widening of right upper mediastinum, two nodular shadows in right middle lobe, and left-sided infiltration shadow with pleural effusion. The pleural effusion was bloody and its level of adenosine deaminase was normal. Culture of pleural effusion specimen remained negative. A computed tomography scans of the chest revealed an aortic aneurysm on the aortic hiatus. Rapid increase in pleural effusion was followed by hemothorax a few hours later. After operation, she received antituberculosis therapy. Histopathologically, the resected lung showed inflammatory process including granulation of giant cells and epithelioid cells. The specimens of the aortic aneurysm revealed rupture of whole layer of aortic wall and inflammatory cell infiltrations. These findings suggested that the case to be a tuberculous aneurysm of the aorta. Therefore, we diagnosed the case as the rupture of tuberculous aneurysm of the aorta.

[Snoring and upper airway resistance syndrome].

Snoring is an inspiratory noise caused by vibration of soft palate and posterior faucial pillars. Snoring corresponds to partial obstruction of upper airway, and complete obstruction is followed by an apnea. Heavy snoring is practically always present in obstructive sleep apnea syndrome. Upper airway resistance syndrome (UARS) was first used by Guilleminault and colleagues to describe a subgroup of patients with conditions that were formerly diagnosed as idiopathic hypersomnia or CNS hypersomnia. These terms used to describe excessive daytime sleepiness without a cause that was clearly defined by a nocturnal polysomnogram or the multiple sleep latency test. The clinical importance of snoring and UARS is reviewed in this article.

Long-term effects nasal continuous positive airway pressure on daytime sleepiness, mood and traffic accidents in patients with obstructive sleep apnoea.

To describe the long-term effects of nasal continuous positive airway pressure (CPAP) on the rate of traffic car accidents, excessive daytime sleepiness (EDS) and mood in patients with obstructive sleep apnoea syndrome (OSAS), we investigated the changes of these parameters before and after nasal CPAP treatment using a questionnaire. Seventy-five male patients who were diagnosed with severe OSAS by polysomnography were evaluated for driving competence, by looking at their driving history for 2 yr, for EDS by the Epwarth Sleepiness Scale (ESS) and for mood by the Self-related Depression Scale (SDS), and then underwent nasal CPAP treatment. After 2 yr of treatment, questionnaires inquiring about the patients' use of CPAP, their ESS, SDS and driving history during treatment were sent to the patients. A total of 47 patients (63%) responded to these questionnaires. Forty-six of the 47 responders had continued to use the nasal CPAP and completed the questionnaire. No traffic car accidents were observed among the 39 routine car users during treatment, while 13 of 39 patients (33%) had had car accidents before treatment. Although near-miss accidents had been reported by 32 of 39 patients (82%) before treatment, only four patients reported near-miss accidents during nasal CPAP treatment. The mean score of ESS was significantly (P<0.01) reduced in 46 patients after nasal CPAP. The mean score of SDS was also decreased (P<0.01) after nasal CPAP in 46 patients. Although 26 of 41 patients had been depressive on SDS before treatment, the mood was improved in 13 patients after nasal CPAP. These results suggest that long-term nasal CPAP treatment reduces the rate of traffic car accidents and improves the EDS and the mood in patients with OSAS.

Two nap sleep test: an easy objective sleepiness test.

The two nap sleep test (TNST) was developed and its usefulness for detecting sleepiness in long-distance drivers has been reported. This study's authors attempted to apply the TNST as a clinical test of sleepiness. A normal control group (n = 29), an obstructive sleep apnea syndrome (OSAS) group (n = 9), and another sleep disorder group (n = 6) participated. As a result of polysomnography, the sleep latency and sleep time did not differ among the groups. In contrast, the frequency of micro-arousal and movement arousal was significantly higher in the OSAS group than in the other groups. The TNST is thought to be useful for evaluating disturbance of sleep maintenance.

Nasal continuous positive airway pressure changes blood pressure "non-dippers" to "dippers" in patients with obstructive sleep apnea.

To evaluate the circadian pattern of blood pressure (BP) and the effects of nasal continuous positive airway pressure (CPAP) on patients with obstructive sleep apnea (OSA), we examined 24-hour BP in 38 male OSA patients with and without nasal CPAP. We measured the BP at 30-min intervals during daytime (800 to 2200) and nighttime (2200 to 800) hours. A "dipper" was defined as a patient who showed an average reduction of at least 10 mm Hg systolic and 5 mm Hg diastolic between daytime and nighttime values. The subjects were predominantly "non-dipper" (22 of 38 patients, 58%). Daytime hypertension (>160/95 mm Hg) was present in 11 of 38 patients (4 "dippers" and 7 "non-dippers"). After nasal CPAP treatment for 3 days, the average BP decreased significantly during the day and night in all subjects (p<0.05). Fifteen of 22 subjects who were "non-dippers" before treatment reversed to become "dippers." And daytime hypertension was detected in only 5 of these patients during nasal CPAP treatment (4 "dippers" and 1 "non-dipper"). These results showed that the "non-dipper" status was common in patients with OSA, and that nasal CPAP restored the normal circadian "dipper" pattern. We suggest that nasal CPAP may contribute to an improved prognosis in patients with OSA because of a reduction in cardiovascular risk factors in "non-dipper" with severe OSA.

Multifocal peripheral bronchial carcinoid tumour.

Peripheral bronchial carcinoids sometimes arise as single solid or nodular lesions in the periphery of the lung. We encountered a 74-year-old Japanese male with bronchial carcinoids that were widely disseminated throughout the lung parenchyma. Pulmonary function tests revealed mild airflow obstruction. A metastatic process was ruled out from primary malignancy and a histological examination revealed findings consistent with a peripheral bronchial carcinoid. Based on these findings, we concluded that this patient had a primary multifocal peripheral bronchial carcinoid. An immunohistochemical examination revealed immunoreactivity for chromogranin A and bombesin. The present case appears to be an unusual case of diffuse multifocal peripheral bronchial carcinoid, confirmed by immunohistochemistry.

Effects of nasal continuous positive airway pressure on pulmonary haemodynamics and tissue oxygenation in patients with obstructive sleep apnoea.

We investigated the acute effects of nasal continuous positive airway pressure (CPAP) on pulmonary haemodynamics and tissue oxygenation in eight men with obstructive sleep apnoea (OSA) by means of right heart catheterization. They were tested at four dosage levels of nasal CPAP: 0, 5, 10, and 15 cmH2O. Nasal CPAP significantly reduced the cardiac index at the 10 and 15 cmH2O doses. The mean pulmonary artery pressure was significantly elevated with 10 and 15 cmH2O, and pulmonary capillary wedge pressure was significantly increased with 15 cmH2O of nasal CPAP. Pulmonary vascular resistance was significantly increased with 10 cmH2O of nasal CPAP. The 5 cmH2O dose of nasal CPAP did not affect significantly these parameters. Mixed venous oxygen tension was unchanged at any pressure. We conclude that tissue oxygenation was maintained in the OSA patients during administration of nasal CPAP, even though a high CPAP clearly affected pulmonary haemodynamics.

[Sleep apnea syndrome in Japan: analysis of pathophysiology and nasal continuous positive airway pressure effectiveness].

Forty eight Japanese sleep apnea syndrome (SAS) patients, whose apnea-hypopnea index (AHI) was more than 30 times/hr. from 5 university hospitals (46 males, 2 females) were enrolled in this study to analyze the characteristics of the disorder and the effectiveness of nasal continuous positive airway pressure (nCPAP) effectiveness. Although the severity of excessive daytime sleepiness (EDS), depressive state, and ventricular premature beats caused by SAS seemed milder in Japanese than reported Caucasian patients, the prevalences of hypertension and glucose intolerance were quite high: 50 and 30% respectively. Treatment with nCPAP for 3 months was completed in 41 of 48 enrollees, a compliance rate of 85.4%, which was substantially higher than studies from Western countries. nCPAP treatment normalized about 50% of hypertensive patients and more than half of glucose intolerant patients. Moreover, EDS, driving ability, the severity of arrhythmia, and so forth were all improved with nCPAP. We, therefore, conclude that 1) SAS could differ between Japanese Caucasians in terms of clinical features resulting from SAS and 2) treatment with nCPAP is effective and should be considered as first-line treatment for patients with moderate to severe SAS, as reported in Western countries.

Acute effects of nasal continuous positive airway pressure on 24-hour blood pressure and catecholamines in patients with obstructive sleep apnea.

To assess the acute effects of nasal continuous positive airway pressure (CPAP) on the 24-hour blood pressure and the secretion of catecholamines in urine and plasma, we investigated the changes in the 24-hour blood pressure and urinary and plasma concentrations of epinephrine (E) and norepinephrine (NE) in 26 men with obstructive sleep apnea (OSA) with and without nasal CPAP. Nasal CPAP resulted in significant decreases in the daytime diastolic pressure (from 86 +/-16 mmHg to 83+/-12 mmHg), the nighttime diastolic pressure (from 81+/-12 mmHg to 77+/-9 mmHg) and the nighttime systolic pressures (from 125+/-15 mmHg to 120+/-10 mmHg). There was no significant difference between patients with and without CPAP in the daytime or nighttime urinary E level, but patients who received CPAP showed a significant decrease in daytime urinary NE level (from 156+/-112 microg/14h to 119+/-101 microg/14h) and nighttime urinary NE level (from 143+/-91 microg/10h to 112+/-65 microg/10h). The morning plasma level of NE also decreased (from 371+/-181 pg/ml to 273 +/-148 pg/ml) in patients who received nasal CPAP (p<0.02), but the plasma level of E remained unchanged. There were no correlations between PSG parameters and the reductions in blood pressure and the catecholamine levels induced by nasal CPAP. These findings suggest that OSA contributes, at least in part, to the development of systemic hypertension by increasing sympathetic nervous activity.

[Long-term effects of nasal continuous positive airway pressure on pulmonary function and blood gas data in patients with obstructive sleep apnea syndrome].

To evaluate the long-term effects of nasal continuous positive airway pressure (NCPAP) on pulmonary function and blood gas levels in patients with obstructive sleep apnea syndrome (OSAS), we examined the pulmonary functions and blood gases in 25 male patients with OSAS before and after NCPAP treatment. After 22 months of treatment (titration: 13 cm H2O), no significant changes were observed in the patients' spirograms, pulmonary gas volumes, or diffusion capacity. However, PaO2 levels increased significantly (p < 0.01), from 73.8 mmHg to 79.5 mmHg; PaCO2 levels decreased significantly (p < 0.05), from 45.6 mmHg to 44.2 mmHg; and A-aDO2 levels also decreased significantly (p < 0.05), from 18.7 mmHg to 15.0 mmHg. The patients were divided into a hypoventilated group (PaCO2 > 45 mmHg; 11 cases) and normoventilated group (PaCO2 < or = 45 mmHg; 14 cases). After NCPAP treatment, increased PaO2 and decreased PaCO2 levels were observed in the hypoventilated group, and increased PaO2 and decreased A-aDO2 levels were observed in the normoventilated group. These results suggest that long-term NCPAP treatment improves gas exchange in OSAS patients without influencing the results of pulmonary function tests.

[Non-surgical treatment of obstructive sleep apnea].

We studied the clinical usefulness of nasal continuous positive airway pressure (CPAP) treatment of obstructive sleep apnea syndrome (OSAS). The subject were 56 men with OSAS. Their mean age, apnea index, and SaO2 were 51 +/- 8 years, 48 +/- 18, and SaO2 were 51 +/- 8 years, 48 +/- 18, and 81 +/- 7%, respectively. After titration of CPAP, they underwent nasal CPAP treatment at home every night. Symptoms, blood pressure, pulmonary function, compliance with the prescription and complications of treatment were evaluated every one or two months in an outpatient clinic. Blood pressure decreased significantly from 135 +/- 15 mmHg (systolic) and 88 +/- 14 mmHg (diastolic) to 126 +/- mmHg (systolic) and 78 +/- 6 mmHg (diastolic) in 51 cases after two weeks of treatment. No significant change in pulmonary function except for blood gases was observed after longterm treatment. Excessive daytime sleepiness disappeared and sleep quality improved after treatment in most cases. Thirty-six of 43 patients continued to use nasal CPAP for 34 +/- 16 months and 33% complied with the prescription. Although nasal mask discomfort and dryness of the nose and mouth occurred in several cases, there were no serious complications. These findings suggest that nasal CPAP is useful for treatment of patients with OSAS. However, the problem remains that the cost of nasal CPAP is not reimbursed by the public health insurance system in Japan.

Daytime hypertension and the effects of short-term nasal continuous positive airway pressure treatment in obstructive sleep apnea syndrome.

Daytime blood pressure (BP) in 31 male patients with obstructive sleep apnea syndrome (OSAS) was measured and the effects of nasal continuous positive airway pressure (CPAP) treatment on daytime BP were studied. Subjects were 48 +/- 10 (mean +/- SD) years old and weighed 80 +/- 13 kg. The mean systolic BP and diastolic BP were 135 +/- 15 mmHg and 88 +/- 14 mmHg, respectively and daytime hypertension was present in 12 (38%) subjects. Apnea index (AI) and the lowest oxygen saturation during sleep were significantly more severe in the hypertensive (HT) than in the non-hypertensive (NHT) patients (p < 0.05). AI was significantly correlated with diastolic BP (p < 0.05) and the mean and lowest oxygen saturation during sleep were significantly correlated with both systolic (p < 0.05) and diastolic BP (p < 0.01). After nasal CPAP treatment for two weeks, both systolic and diastolic BP were significantly reduced; the former from 135 +/- 15 mmHg to 126 +/- 10 mmHg (p < 0.005) and the latter from 88 +/- 14 mmHg to 78 +/- 6 mmHg (p < 0.001). These data form direct evidence that daytime hypertension is partially induced by OSAS and is reversible with nasal CPAP treatment.

[Organ failure due to hypoxemia, and effects of oxygen therapy--effects of hypoxemia on pulmonary hemodynamics, and improvement with oxygenation].

To investigate pulmonary hemodynamics in patients with chronic respiratory failure, we performed right heart catheterization and also examined the effects of oxygen inhalation. Thirty-three patients were studied. Their mean age was 65 +/- 10 years, and FEV1.0% and PaO2 on room air were 47 +/- 16% and 63 +/- 14 mmHg, respectively. mPAP was 27 +/- 10 mmHg, and 26 (78%) had pulmonary hypertension. Although PVR was abnormally high, CI and PCWP were within normal limits. PaO2 was significant Significantly correlated with mPAP and PVR. Although oxygen inhalation (28%) for 30 minutes significantly changed PaO2, PaCO2, and PvO2, it did not significantly affect mPAP, PVR, CI, or PCWP. These results suggest that short-term oxygen inhalation does not affect pulmonary hemodynamics in patients with chronic respiratory failure. Radionuclid ventriculography was also done to evaluate cardiac function in 16 patients before and after home oxygen therapy (HOT). Both right ventricular ejection fraction (RVEP) and left ventricular ejection fraction (LVEF) were significantly increased by HOT, and the significant correlation between RVEF and LVEF that had been observed before HOT disappeared. These results suggest cardiac function improved and that the interdependence between the right and left ventricle was eliminated by HOT.