[Long-term theophylline therapy in sleep apnea--follow-up over a period of 12 months]

Among all the sleep-related respiratory disorders, sleep apnoea is clinically the most important one because of its high incidence and potential cardiovascular sequelae. Treatment depends upon the risk profile of the individual patient; in severe cases or in risk patients nasal continuous superpressure ventilation is employed, whereas in milder cases theophylline has been successfully used alongside general measures. 103 patients were followed up during treatment on an outpatient basis for 2 to maximum 12 months. Initially a significant reduction of the apnoea index by a 50% average was achieved. This therapeutical effect remained largely constant with a slight average deterioration at the end of the observation period, whereas the subjective feeling tone also improved in most patients. The treatment course was prematurely discontinued in 34 patients. Good to very good success was achieved in a total of 43 patients, whereas 26 patients were non-responders either initially or as the treatment proceeded. Even though theophylline treatment is now well-tried in mild forms of sleep apnoea, predictors for its use in certain groups of patients must be determined before treatment is initiated.

Beneficial effect of inhaled CO2 in a patient with non-obstructive sleep apnoea

A 63-year-old man with severe non-obstructive sleep apnoea (apnoea index 28; apnoea duration 45-60s; O2 saturation between 72% and 98%), who did not respond to common modes of treatment, was successfully treated with CO2. A tent was perfused with compressed air (6 1/min) and increasing amounts of CO2. A concentration of 3% CO2 (180 ml/min) was sufficient to raise the PaCO2 above apnoea threshold and to suppress apnoeas completely. As a result, O2 saturation remained normal throughout the whole night and the symptoms of sleep apnoea disappeared. We hypothesize that the PCO2 ventilatory drive was intact in our patient and that hypocapnia was the major factor causing the non-obstructive sleep apnoea syndrome. Administration of CO2 with a constant flow system could be a safe and easy alternative for patients with non-obstructive sleep apnoea syndrome who present with hypocapnia and an intact respiratory feedback control system.

Shifts and awakenings: valuable indicators of the quality of sleep: do these parameters react differently to hypnotics?

In order to test the assumption that the sleep stability increases as the number of shifts and awakenings decreases, all-night sleep recordings (registered at home) were reanalyzed. The registrations belong to 10 young good sleepers, 10 adult good sleepers, 10 insomnia patients without treatment, 10 treated with a benzodiazepine and 10 treated with a nonbenzodiazepine hypnotic, 10 patients with proven narcolepsy, and 10 with obstructive sleep apnea syndrome (OSAS). For each of the categories NREM-1-2, NREM 3-4, and REM sleep, indices were defined as the number of shifts and awakenings that occurred per hour. Our results show that the indices of awakenings for the good as well for the bad sleepers were similar, whereas the indices of awakenings were very group dependent. We interpreted these results as showing that awakenings are valuable indicators for studying the quality of sleep, whereas shifts are not.

Effects of zolpidem and triazolam on sleep and respiration in mild to moderate chronic obstructive pulmonary disease

Sleep problems and nocturnal arterial oxygen desaturation are common in patients with chronic obstructive pulmonary disease (COPD). Hence, the safety and efficacy of new hypnotic agents must be ascertained in this group of patients. We performed a double-blind, randomized, single-dose, placebo and active drug controlled, crossover study in 24 patients with insomnia (subjective sleep latency > 30 minutes and sleep duration 4-6 hours) and mild to moderate COPD (mean FEV1 61 +/- 12(SD)% predicted) in order to establish the effects of zolpidem 5 mg and 10 mg on sleep and respiration and to compare these effects with triazolam 0.25 mg. Arterial oxygen saturation for the entire night, by hour and stage, and the apnea-hypopnea index for the entire night were not significantly different with placebo and the various drug conditions. Total sleep time and sleep efficiency were increased over placebo by all three drug conditions. Triazolam was more effective than zolpidem 5 mg but not zolpidem 10 mg, and there was no significant difference between zolpidem 5 mg and zolpidem 10 mg. Zolpidem 10 mg and triazolam both reduced the number of awakenings (> 15 seconds duration) per hour of sleep. Although there was a trend for triazolam to be more efficacious than zolpidem 10 mg, no statistically significant difference was found for any objective or subjective sleep variable. Likewise, zolpidem 10 mg tended to be more efficacious than zolpidem 5 mg, but the difference was only significant in terms of perceived sleep quality and ease of falling asleep.(ABSTRACT TRUNCATED AT 250 WORDS)

[Therapy control of theophylline evening dosage in patients with sleep-related respiratory disorders--follow-up study]

We conducted a prospective study to perform classification according to responder types and follow-up during theophyllin treatment (500 mg/d) in a group of (up to now) 65 patients suffering from sleep apnoea. Changes in the apnoea index (AI) and clinical symptoms were taken as response criteria. A significant AI reduction was seen during a follow-up period of 3 months. At the last control measurement after 6 months no significant change has been detected so far. 10 patients were classified as Type I responders (improvement in initial AI 60%, over the total period at least 25%). No patient had a responder type II profile. 13 patients were nonresponders (improvement in initial AI and over the whole period not more than 25%, no improvement in the pattern of clinical symptoms). 13 patients dropped out of the trial due to non-compliance. Side effects typical of theophyllin leading to discontinuation of the treatment course occurred in 5 patients. 22 patients have not yet completed the course at the time of writing. Standardised questioning of patients showed a definite improvement in feeling tone, especially with regard to the tendency to fall asleep during the day and refreshed feeling in the morning. Nocturnal complaints occurred in only a few isolated cases. Hence, administration of theophyllin retard preparations in evening doses of 500 mg/d remains a meaningful therapeutic approach to sleep apnoea.

[Treatment of obstructive sleep apnea syndromes]

The detection, correction or withdrawal of any cause or associated factor including obesity, drugs or alcohol is essential in the treatment of obstructive sleep apnea syndrome. Treatment is mainly mechanical or surgical, but not medical. Nasal continuous positive airway pressure (NCPAP) has now largely replaced tracheostomy and successful long-term domestic use of this method has been reported on many occasions. Oropharyngeal surgery can solve a large part of social snoring problems. However criteria for procedure selection and evaluation of results are still needed to clarify the indication of this operation in patients with full clinical expression of the syndrome. In this regard, a comprehensive preoperative evaluation and a logical approach to the reconstruction of the upper-airway has recently led to the association of palatopharyngoplasty and maxillo-mandibular surgery, with an excellent long-term success rate.

Hypnotics should never be used in patients with sleep apnea

Although benzodiazepine medication is generally considered to be inappropriate for patients with obstructive sleep apnea, further investigation is required to evaluate this. Non-benzodiazepine hypnotics may improve sleep quality without causing respiratory depression. In central sleep apnea, hypnotics not only improve sleep but also decrease apnea frequency probably by reducing arousals and elevating arterial PCO2. Consequently, I submit that the statement 'hypnotics should not be used in patients with sleep apnea' should be changed to 'hypnotics may sometimes be used in patients with sleep apnea'.

Obstructive sleep apnea in the Rubinstein-Taybi syndrome

The Rubinstein-Taybi syndrome is characterized by a pattern of malformations including broad thumbs and big toes, microcephaly, facial dysmorphism, small stature, and mental retardation. Obstructive sleep apnea (OSA), has been described in several facial or skeletal malformations, but never in the Rubinstein-Taybi syndrome. We studied a 9-year-old boy, previously diagnosed as having the Rubinstein-Taybi syndrome and affected by severe OSA, as documented by polysomnography. He manifested the habitual and heavy snoring with breathing difficulties at night, and excessive daytime sleepiness. Short neck and obesity were important factors for the severity of the syndrome. Continuous positive airway pressure was not tolerated and weight loss was the only possible treatment, as upper airway surgery was not indicated by cephalometric, otolaryngologic or clinical results.

Obstructive, mixed, and central apnea in the neonate: physiologic correlates

In an attempt to determine physiologic responses to neonatal apnea, we evaluated changes in heart rate and oxygen saturation as measured by pulse oximetry during 2082 episodes of apnea lasting 15 seconds or more in 47 infants less than 34 weeks of gestational age with idiopathic apnea of prematurity. Of these episodes, 832 (39.9%) were central, 1032 (49.6%) were mixed, and 218 (10.5%) were obstructive. Oxygen saturation decreased with increasing duration of apnea regardless of type or treatment, and the decrease in saturation was correlated with preapnea saturation. The baseline heart rate was similar for all apnea types. Infants receiving doxapram had a lower baseline heart rate (137.8 +/- 10.5 beats/min) than did infants receiving no therapy (142.8 +/- 16.6 beats/min) and infants receiving theophylline (149.7 +/- 15.0 beats/min) (p = < 0.001). A heart rate fall to less than 100 beats/min was seen more frequently with central apnea than with mixed or obstructive events, and in infants who were not receiving therapy. Falls in heart rate were significantly less in infants receiving doxapram (27.8% +/- 18.0%) than in infants receiving theophylline (44.5% +/- 19.0%) or no therapy (48.4% +/- 18.3%) (p = < 0.001). The most common heart rate pattern overall was a gradual decrease interrupted by accelerations, whereas an initial heart rate acceleration was the most common pattern in obstructive apnea. We conclude that heart rate response to neonatal apnea is a complex and is dependent on therapy and on type and duration of apnea.

[Improvement of respiratory function with weight reduction in obese elderly]

The patient was a 74-year-old woman who had been obese since age 18. Her obesity was refractory to dietary manipulation. She had been suffering from increasing dyspnea for several months and eventually could not even move. She was admitted to a hospital and diagnosed as having heart failure. Although her cardiac function recovered with medical treatment, her symptoms did not improve. The patient was then sent to our hospital. On admission, her height and weight were 149 cm and 81.9 kg, respectively, yielding a body mass index (BMI) of 36.6 kg/m2. Arterial blood gas analysis in room air revealed hypoxemia and an apnea index of 27 per hour. She was given a daily 500-1000 kcal diet. After four months of treatment, her weight decreased to 65 kg with a BMI of 29.3 kg/m2. Weight reduction together with the usage of progesterone-derivatives resulted in marked improvement of sleep apnea. The apnea index decreased to 3/h and arterial blood gas values normalized. This patient seemed to have suffered from both obesity hypoventilation syndrome and sleep apnea syndrome. Improvement of respiratory function was achieved through relief of airway obstruction and weight reduction, with activation of the respiratory center due to progesterone treatment.

Sleep apneas and high altitude newcomers

Sleep and respiration data from two French medical high altitude expeditions (Annapurna 4,800 m and Mt Sajama 6,542 m) are presented. Difficulties in maintaining sleep and a SWS decrease were found with periodic breathing (PB) during both non-REM and REM sleep. Extent of PB varied considerably among subjects and was not correlated to the number of arousals but to the intercurrent wakefulness duration. There was a positive correlation between the time spent in PB and the individual hypoxic ventilatory drive. The relation between PB, nocturnal desaturation, and mountain sickness intensity are discussed. Acclimatization decreased the latency toward PB and improved sleep. Hypnotic benzodiazepine intake (loprazolam 1 mg) did not worsen either SWS depression or apneas and allowed normal sleep reappearance after acclimatization.

Obstructive sleep apnea in Arnold-Chiari malformation treated with acetazolamide

We studied respiratory patterns and transcutaneous gas pressures in two infants with Arnold-Chiari type II malformation referred to us due to repeated episodes of stridor and cyanosis. During both active and quiet sleep, respiration was irregular and absent or inverse thoracic breathing movements and frequent decreases in oxygen saturation to below 80% were observed. When breathing air with 2% CO2 or when given acetazolamide 10 mg/kg, chest wall movements normalized and oxygenation increased to near normal levels. After three months of treatment with acetazolamide 20 mg/kg/24 h no further episodes of hypoventilation or hypoxemia were observed and further treatment could be discontinued. We conclude that stimulation of respiration by CO2 or by acetazolamide appears to recruit chest wall muscles and promote upper airway patency in Arnold-Chiari malformation. A treatment trial with acetazolamide seems justifiable in these infants when respiratory problems are present.

[Primary hypothyroidism with obstructive sleep apnea syndrome]

The relationship between severity of hypothyroidism and OSA syndrome before and after treatment was analyzed and discussed. All patients had typical clinical features of primary hypothyroidism and were diagnosed by thyroid hormonal investigations. They were treated with conventional desiccated thyroid. Polysomnography and blood oxygen saturation % (SaO2%) were performed during sleep before and after substitutive treatment. In this series of 21 patients taking respiratory functional tests, 11 were consistent with OSA (42.4%). The serum values of TT4, FT4I, TT3 and TSH after treatment were markedly different from the initial values in 9 cases who were followed up after treatment (P < 0.001, respectively). The respiratory parameters including maximum apnea time, mean apnea time, respiratory disturbances index and the lowest oxygen saturation % were also markedly different in patients before and after treatment (P < 0.001-0.02, respectively). The serum levels of TT4 and FT4I were significantly correlated with the values of maximum and mean apnea time and the highest oxygen saturation % after substitution (r = 0.64-0.98, P < 0.01-0.05, respectively). We conclude that OSA in hypothyroidism showed the most satisfactory response to non-surgical treatment, and OSA syndrome could be cured as soon as hypothyroidism was controlled by desiccated thyroid.

[A case of multiple sclerosis with intractable hiccups and sleep apnea syndrome]

A 48-year-old female with multiple sclerosis (MS) accompanied by intractable hiccups of over one month' duration and the sleep apnea syndrome was reported. This MS patient had been well controlled until September 16, 1991 when she experienced nausea, vomiting and hiccups. The patient was admitted to Kawasaki Medical School Hospital on October 9, 1991. A physical examination revealed intractable hiccups. T1-weighted MRI showed a low and T2-weighted image disclosed a high signal intensity area in the tegmentum of the medulla oblongata. The intractable hiccups and vomiting improved with intravenous high dose methylprednisolone injection therapy. The following day, she complained of insomnia and her family observed severe snoring and apnea during the night. These symptoms and the results of a breathing monitor were compatible with the sleep apnea syndrome. These symptoms disappeared following the administration of amitriptyline. There have been few reports of the combination of intractable hiccups and the sleep apnea syndrome in MS. The MRI findings suggest that the causative lesion of these symptoms is in the tegmentum of the medulla oblongata.

Effects of enhancing slow-wave sleep by gamma-hydroxybutyrate on obstructive sleep apnea

Sleep apneas are rarely observed during slow-wave sleep (SWS), which is poorly represented in patients with obstructive sleep apnea (OSA). Gamma-hydroxybutyrate (gamma OH), a natural metabolite of the brainstem, increases the percentage of total sleep time (TST) spent in SWS. We evaluated the effects of gamma OH on sleep and breathing disorders in eight patients with OSA (age, 45 +/- 2 yr; body mass index, 35.0 +/- 1.5 kg/m2; mean +/- SEM). Three conventional sleep studies were done within a week; the first and third were control studies, and the second was the gamma OH study (30 mg/kg at bedtime and 3 h later). Because the effects of the drug last only 3 h, we analyzed and compared the results of the first 6 h of sleep recording. The percentage of TST spent in SWS increased with gamma OH (30.7 +/- 3.9%) compared with that in the control studies (12.5 +/- 1.1 and 11.0 +/- 2.1%) at the expense of stages I and II. There was no difference between apnea index obtained during the control studies (26.3 +/- 5.3 and 25.4 +/- 6.2/h) and that obtained during the gamma OH study (29.6 +/- 4.9/h). Most apneic events occurred during Stages I and II, and REM, but this proportion was less during the gamma OH study (77.9 +/- 8.9%) than during the control studies (92.3 +/- 1.9 and 95.9 +/- 2.2%), apneas occurring even during SWS with gamma OH.(ABSTRACT TRUNCATED AT 250 WORDS)

Theophylline in obstructive sleep apnea. A double-blind evaluation

Twelve patients with documented obstructive sleep apnea were enrolled in a double-blind placebo controlled crossover trial of oral theophylline, (Uniphyllin) 800 mg, taken at night for four weeks. Overnight polysomnography, using standard techniques, was performed at the end of each treatment period. The total number of apneas (A) and hypopneas (H) decreased significantly while receiving theophylline compared to placebo, from 398 (69), mean (SEM), to 283 (72), p less than 0.01. Sleep quality was, however, significantly worse while receiving theophylline. Obstructive A and H were very much decreased with theophylline (p less than .001), and even when the data were adjusted for the more disturbed sleep with theophylline, this decrease remained significant; the obstructive A and H index fell from 49 (8.7) on placebo to 40 (9) while receiving theophylline, p = 0.02. There was no difference in the numbers of central or mixed A and H, and mean A and H duration was unchanged on the two study nights. Oxygen desaturations greater than 4 percent were less with theophylline treatment (p = 0.02), but mean overnight SaO2 was unchanged. We conclude that theophylline may be beneficial in patients with OSA, but part of the improvement is due to a deterioration in sleep quality.

Effect of clonidine in obstructive sleep apnea

The current treatment of choice for obstructive sleep apnea is continuous positive airway pressure. However, not all patients tolerate this form of therapy. We evaluated the effect of clonidine hydrochloride, an alpha 2-adrenergic agonist with REM-suppressant activity, in eight male patients with obstructive sleep apnea. In each patient, sleep-stage distribution and breathing pattern in two all-night sleep studies performed during a 10-day course of clonidine were compared with those of two control and two placebo nights. A dose of 0.2 mg of clonidine administered orally at bedtime totally suppressed REM sleep in two patients. In the other six patients, the same dose decreased percent time spent in REM sleep from a control of 13.4 +/- 1.0 to 8.6 +/- 1.4% (mean +/- SEM, p less than 0.05). The latency to REM sleep increased in the latter group from a control of 129 +/- 9 to 308 +/- 24 min (p less than 0.001). Clonidine had no effect on the frequency and duration of non-REM breathing abnormalities. Under clonidine, the level of nocturnal hypoxemia improved in six patients. This was due to a total suppression of REM and the consequent lack of REM apneas in two patients. In four patients, upper airway obstruction disappeared during period of unsuppressed REM sleep, and SaO2 remained above 90% throughout this sleep stage. Clonidine transformed the pattern of sleep-disordered breathing during unsuppressed REM in the other two patients from that of repetitive obstructive hypopneas associated with persistent hypoxemia to occlusive apneas and cyclical hypoxemia. These results were observed consistently in all patients during both clonidine-sleep studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Branched-chain amino acid in chronic renal failure patients: respiratory and sleep effects

Sleep disorders, including a high incidence of sleep apnea, have been recognized as a significant problem in chronic renal failure (CRF) patients. In a preliminary study, we examined CRF patients on maintenance hemodialysis for three nights; one control night, and thereafter randomized to infusion of saline (placebo) for one night and 4% branch-chain amino acid (BCAA) solution for one night. Polysomnographic and respiratory data [respiratory rate, oxygen saturation and end-tidal CO2 (ETCO2)] was recorded continuously throughout the nights and data from each hour compared with baseline (awake) values. The patients studied were characterized by reduced sleep quality and decreased amount of rapid eye movement (REM) sleep. The BCAA infusion was associated with a return of REM sleep to normal and a significant decrease in ETCO2 during both REM and non-REM sleep (P less than 0.05). Our findings demonstrate respiratory stimulation during sleep with infusion of BCAA; this stimulatory effect on respiration (in contrast to many respiratory stimulants) is associated with an increased amount of REM sleep.

Response of obstructive sleep apnea to fluoxetine and protriptyline

Protripyline is the pharmacologic agent most commonly used to treat obstructive sleep apnea (OSA); however, its anticholinergic side effects make it intolerable to many patients. Because serotonin may be a central respiratory stimulant and because the serotonin-uptake inhibitor, fluoxetine, is usually well tolerated, we wanted to try fluoxetine in the treatment of OSA. Therefore, we compared the effect of fluoxetine to that of protriptyline in 12 patients with OSA. Both drugs significantly decreased the proportion of REM sleep time and decreased the number of apneas or hypopneas in NREM sleep. The response to fluoxetine was equivalent to that of protriptyline; however, for the group as a whole, there was no significant improvement in the number of arterial oxygen desaturation events, the level of arterial oxygen desaturation, or the number of arousals with either agent. Although there was wide variability in the response to each medication, six of the 12 patients had good responses, including improvement in oxygenation, to either fluoxetine or protriptyline. Three patients could not complete the trial of protriptyline. We conclude that fluoxetine is beneficial to some, but not all, patients with OSA. Fluoxetine was better tolerated than protriptyline.