[A case of obstructive sleep apnea syndrome remarkably improved by gastric restriction surgery].

A 23-year-man with morbid obesity and obstructive sleep apnea syndrome (OSAS) was admitted. He was 170 cm in height and 170 kg in weight. He underwent dietary treatment several times, but his weight returned to its original level, or even higher, within a short period. A diagnosis of OSAS was made by nocturnal polysomnography. In this morbidly obese patient with OSAS a nocturnal sleep apnea study was performed before and after weight reduction surgery (gastric restriction). The postoperative findings revealed a dramatic body weight reduction. At the same time, the results of apnea and oxygen desaturation were remarkably improved too. These results indicate that weight reduction surgery is a definitely effective treatment for morbid obesity associated with OSAS.

Influence of nocturnal oxygen desaturation on circadian rhythm of testosterone secretion.

To investigate the influence of nocturnal oxygen desaturation on the circadian rhythm of testosterone secretion, polysomnography was performed on 2 consecutive nights in 24 male subjects who complained of loud snoring and/or obesity. During the first night, we collected blood samples every 4 h via a catheter and measured serum testosterone. We arbitrarily defined severe oxygen desaturation as that exceeding the baseline SaO2 by 4% during 80 min of total sleep time. The subjects were divided into 2 groups from the data of the second night; one was the severe desaturation group as mentioned above, and those who suffered less desaturation were classified as the free to mild oxygen desaturation group. We found that in the latter group peak testosterone levels appeared at 6 a.m. On the other hand, the severe desaturation group exhibited delayed peak testosterone levels, i.e. at 10 a.m. We calculated the ratio of the testosterone level at 10 a.m. to that at 6 a.m., and found a significant correlation between this ratio and total desaturation time (r = 0.446, p less than 0.05). These data suggest that severe oxygen desaturation may alter the circadian rhythm of testosterone secretion.

[Indications for home oxygen therapy in cases of sleep oxygen desaturation].

Home oxygen therapy is now considered indicated in cases of severe sleep oxygen desaturation. To explore whether we could choose cases with severe sleep desaturation by measurement of waking physiological parameters, we examined the relationship between arterial blood gases, lung functions and pulmonary artery pressure while awake and the degree of sleep oxygen desaturation in 21 patients with chronic obstructive pulmonary disease and 22 cases with a past history of pulmonary tuberculosis. There were significant correlations between waking PaO2, PaCO2 and pulmonary artery mean pressure and sleep lowest SaO2, respectively, whereas no significant relation was found between %VC or FEV1.0% and sleep lowest SaO2. However, we found wide ranges of PaO2 and PaCO2 in cases who had 10 min or more with SaO2 below 85% during sleep. This was also true in the patients who underwent 60 min or more with SaO2 below 85% while a sleep. These results suggest that it may be difficult to find out the indications for cases with severe sleep desaturation by evaluation of arterial blood gases while awake.

[Prediction of the degree of nocturnal oxygen desaturation in sleep apnea syndrome by estimating the testosterone level].

We studied the influence of hypoxia due to sleep apnea on testosterone (T) secretion. It was conducted on the basis of an idea that sustained hypoxia may depress T secretion. The subjects consisted of 15 male patients with no drug administration whose complaints were snoring and/or obesity. The subjects participated in a sleep study on two consecutive nights. During the first night we collected blood samples starting every 4 hours from 10 PM via a catheter and measured T. From the data of the second night, we calculated total desaturation time with more than 4% from the baseline SaO2. According to the amount of this desaturation time, the subjects were divided into 2 groups; desaturation time less than 80 min in group 1 and longer in group 2, respectively. The peak value was seen at 6 AM in group 1 and at 10 AM in group 2. We investigated the correlation between the ratio of T10/T6, which is the ratio of T level at 10 AM to that at 6 AM, and parameters of sleep disorders related to oxygen desaturation. Total 4% desaturation time in total sleep period and non REM period significantly correlated with this ratio. From the diagram illustrating the correlation between the ratio and total 4% desaturation time in total sleep period, we could assume that if the ratio is beyond 1, the subject may have had more than about 80 min of total 4% desaturation time.

Progesterone therapy for sleep apnea syndrome evaluated by occlusion pressure responses to exogenous loading.

We investigated the mechanisms of the beneficial effect derived from progesterone therapy for sleep apnea syndrome (SAS). Nine patients with SAS were treated for 7 days with chlormadinone acetate (CMA), a respiratory stimulant known to increase not only CO2 and hypoxic chemosensitivity but also respiratory drive response for ventilatory loading. They were examined as to sleep events and ventilatory control during wakefulness before and during CMA treatment. Apnea-hypopnea index was significantly reduced from 51.1 +/- 5.7 to 43.6 +/- 8.1 episodes/h (p less than 0.05). The ratio of desaturation time with more than 4% SaO2 fall to total sleep time was diminished in seven of nine patients, and its mean value decreased from 44.9 +/- 8.6 to 28.7 +/- 8.1% (p less than 0.05). Both hypercapnic ventilatory response (HCVR) and load response during wakefulness were significantly increased, although isocapnic hypoxic ventilatory response (HVR) was not significantly enhanced by CMA. The degree of augmentation in awake load response as well as in HCVR was positively correlated with that of improvement in sleep-disordered breathing. Moreover, patients who did not show amelioration in oxygen desaturation were found to be incapable of increasing load response despite increased HCVR. We conclude that CMA therapy for sleep apnea syndrome is effective in the patients whose load response as well as respiratory control activity are augmented during wakefulness.

[Depression of testosterone secretion in male patients with respiratory failure].

To investigate the changes of testosterone (T) secretion under sustained hypoxia, we determined basal levels of urine T, 17 ketosteroid, luteinizing hormone releasing hormone (LHRH), luteinizing hormone (LH), follicle stimulating hormone (FSH) and response to LHRH and HCG (human chorionic gonadotropin) in male patients with respiratory failure. After evaluating blood gas data, we also measured serum T, LH, FSH, plasma progesterone (P) and 17 hydroxyprogesterone (17OH-P). The subjects were divided into 3 groups according to PaO2; Group 1 with a PaO2 under 60 Torr, Group 2 with a PaO2 between 60 Torr and under 70 Torr, Group 3 was an age-matched control group. Urine T and serum T were significantly lower in Group 1 compared with those of Group 3. In the LHRH test, augmented relative responsiveness and delayed peak value in LH secretion were observed in Group 1, compared with those of Group 3. As for the HCG test, no differences were observed among the 3 groups. The ratio of 17OH-P to P, which indicates activity of 17-hydroxylase, was observed to be diminished with increasing degrees of hypoxia. These data suggest that in male patients with respiratory failure there was depression in T secretion as well as 17-hydroxylase activity due to hypothalamic-pituitary hypofunction.

Obese patients with sleep apnea syndrome treated by progesterone.

Two obese patients with sleep apnea syndrome were administered chlormadinone acetate (CMA), a synthetic progesterone, known as a potent respiratory stimulant to augment load compensation response as well as CO2 chemosensitivity. Before CMA administration, both cases showed normal chemosensitivity of hypoxic and hypercapnic ventilatory responses (HVR and HCVR) at daytime, although marked oxygen desaturation with sleep apnea was observed. During CMA administration for 7 days, HVR, HCVR and occlusion pressure response to flow-resistive loading were altogether augmented. In one case obstructive sleep apnea (OSA) was altered to obstructive hypopnea, and in the other case central apnea disappeared completely, resulting in remarkable improvement of oxygen desaturation at sleep and daytime somnolence in both cases. We conclude that CMA might be useful in the treatment of sleep apnea syndrome.