[Effect of salmeterol in obstructive sleep apnea syndrome]

The effect of inhaled long-acting beta 2-agonists on obstructive sleep apnoea syndrome (OSAS) is unknown, though from the pharmacological point of view both therapeutic and adverse effects might be discussed. The purpose of this study was to obtain data on the efficacy and safety of Salmeterol in patients with OSAS. In a randomised, double-blind, placebo-controlled, crossover study effects of Salmeterol were investigated in 20 patients with OSAS: 4 female, 16 male; age 53.0 +/- 7.8 years, body mass index (BMI) 28.0 +/- 3.0 kg.m-2; apnoea hypopnoea index (AHI) 35.6 +/- 17.8 h-1. Patients with asthma, chronic obstructive pulmonary disease (COPD), and left heart failure were excluded. Placebo or verum (50 micrograms Salmeterol) were administered at 7 p.m. by metered dose inhaler and spacer device. All patients underwent full polysomnography during baseline, placebo, and verum night. Statistical analysis was performed by Student's t-test (p < 0.05). Between placebo and verum there were no differences in total sleep time, sleep stages, apnoea index (AI), AHI, and nadir SaO2. There was, however, a significant deterioration of mean SaO2 (placebo 93.1 +/- 2.0 vs Salmeterol 92.5 +/- 2.2%) and of relative time spent with SaO2 < or = 90% (placebo 13.1 +/- 14.5 vs Salmeterol 19.5 +/- 20.8%), as well as a significant increase in heart rate (placebo 63.1 +/- 9.2 vs Salmeterol 65.6 +/- 9.3 h-1). Thus, in patients with OSAS Salmeterol had no adverse effect on quality of sleep, AI or AHI. The slight increase in heart rate and the deterioration of oxygen saturation are clinically irrelevant. The latter might be due to ventilation-perfusion-mismatch. This study demonstrates that Salmeterol has no influence on obstructive sleep apnoea and hypopnoea, but on the other hand provides an acceptable safety profile in OSAS. This might be of special importance in patients suffering from both OSAS and obstructive airway disease.

Sleep-disordered breathing and neuropsychological deficits. A population-based study

The relationship of sleep-disordered breathing (SOB) to neuropsychological deficits was investigated with cross-sectional data from the Wisconsin Sleep Cohort Study, a population-based study of the natural history of SDB. A sample of 841 employed men and women ages 30 to 60 yr was studied by overnight polysomnography to assess the frequency of apneas and hypopneas per hour of sleep (apnea-hypopnea index, AHI). Prior to overnight polysomnography, the participants were given a battery of neuropsychological tests for functionally important capacities including motor skills, attention, concentration, information processing, and memory. Principal factor analysis of all the neuro-psychological test data revealed a psychomotor efficiency and a memory factor. Multiple regression analysis showed a significant negative association between logarithmically transformed AHI (LogAHI) and psychomotor efficiency score independent of age, gender, and educational status (p = 0.017). The relationship was not explained by self-reported sleepiness. No significant relationship was seen between LogAHI and memory score. In assessing the clinical significance of mild SDB, we estimate that an AHI of 15 is equivalent to the decrement in psychomotor efficiency associated with 5 additional yr of age, or to 50% of the decrement associated with hypnosedative use.

Adenosine A1 receptor agonist GR79236 suppresses apnea during all sleep stages in the rat

We tested the hypothesis that N-[(1S, trans)-2-hydroxycyclopentyl]adenosine (GR79236), a novel adenosine A1 receptor agonist, would suppress sleep-related apnea in the rat at doses not associated with hypotension or hypothermia. Nine adult Sprague-Dawley rats were instrumented for chronic recording of sleep by electroencephalographic and electromyographic monitoring. Respirations were measured by single chamber plethysmograph, and blood pressure and heart period were transduced by a telemetric implant. Each rat was polygraphically recorded for 6 hours on four occasions in random order, with recordings for an individual animal separated by at least 3 days. Fifteen minutes prior to each recording (0945 hours) each animal received a 1 ml/kg intraperitoneal bolus injection of one of four injectates: saline (control) or 0.03 mg/kg, 0.3 mg/kg, or 3 mg/kg of GR79236. The study was a repeated-measures balanced design such that each animal was recorded exactly once for each injectate. The rate of spontaneous apneas (pauses > 2.5 seconds) was significantly reduced during all sleep stages by all doses of GR79236. At the highest dose, apnea index was reduced by over 70% in both non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. In contrast, GR79236 had no effect on sleep stage volumes or blood pressure at any dose tested. Heart rate and core temperature were reduced only at the highest dose (3 mg/kg). We conclude that the adenosine A1 receptor agonist GR79236 significantly suppresses apnea expression in all sleep stages at doses not associated with significant changes in sleep architecture, blood pressure, heart rate, or core temperature.

Do systemic corticosteroids effectively treat obstructive sleep apnea secondary to adenotonsillar hypertrophy?

To determine if pediatric obstructive sleep apnea syndrome (OSAS) caused by adenotonsillar hypertrophy (ATH) could be treated by a short course of systemic corticosteroids, we conducted an open-label pilot study in which standardized assessments of symptomatology, OSAS severity, and adenotonsillar size were performed before and after a 5-day course of oral prednisone, 1.1+/-0.1 (+/-SE) mg/kg per day. Outcome measures included symptom severity, adenotonsillar size, and polysomnographic measures of OSAS. Selection criteria included age from 1 to 12 years, ATH, symptomatology suggesting OSAS, an apnea/hypopnea index (AHI) > or = 3/hour, and intent to perform adenotonsillectomy. Only one of nine children showed enough improvement to avoid adenotonsillectomy. Symptomatology did not improve after corticosteroid treatment but did after removal of tonsils and adenoids. Polysomnographic indices of OSAS severity did not improve after corticosteroid treatment. After corticosteroids, tonsillar size decreased in only two patients, adenoidal size was only marginally reduced, and the size of the nasopharyngeal airway was not significantly increased. These results suggest that a short course of prednisone is ineffective in treating pediatric OSAS caused by ATH.

Effect of angiotensin converting enzyme inhibition [Cilazapril] on blood pressure recording in hypertensive obstructive sleep apneic patients

We investigated the efficacy of an Angiotensin Converting Enzyme [ACE] inhibitor on daytime and night-time blood pressure in 55 male hypertensive patients with moderately severe to severe obstructive sleep apnea. We resolved to determine if treatment oriented towards the reduction of hypertension would be successful, despite persistent repetitive hypoxemia and sleep-disordered breathing. The study was a randomized, double-blind, single daily dose, placebo-controlled protocol, with 8 days drug intake (placebo or 2.5 mg Cilazapril) and monitoring on the final day of drug administration. Subjects underwent continuous 24-h arterial blood pressure monitoring during baseline and treatment conditions. Polysomnography was performed at night during the 24-h arterial monitoring period. Cilazapril (2.5 mg) lowered systolic, diastolic and mean blood pressure, despite persistence of repetitive obstructive apneas during sleep and the associated repetitive hypoxemia. The lowering of blood pressure occurred without a significant change in heart rate, and was noted during nocturnal sleep, performance testing and graded exercise.

Medroxyprogesterone acetate in the treatment of obstructive sleep apnea

The use of MPA in patients with OSA is limited. Instead, patients with OSA should be encouraged to abstain from alcohol and respiratory depressive agents, and avoid sleeping in the supine position. In general, patients with OSA are most effectively treated with CPAP and/or surgery. Patients need to be encouraged to maintain ideal body weight, since this has been associated with a marked reduction in symptoms. For patients who are not surgical candidates or refuse to use CPAP, drug therapy may be beneficial. Fluoxetine has been shown to be as effective as protriptyline, and is better tolerated. However, further study is needed to determine whether selective serotonin-reuptake inhibitors are beneficial in treating OSA. Therefore, MPA therapy should be reserved for hypercapnic patients who refuse other modalities of treatment. The potential long-term adverse effects of MPA must be addressed before initiating therapy in men with OSA.

Theophylline for infants with abnormal pneumographic results. A randomized double blind, placebo-controlled trial

To evaluate the effectiveness of theophylline on density of central apnoeas and on incidence of periodic breathing; to compare the effect with age-related resolution of pneumogram abnormalities. Ninety-six infants (mean age 27.4 days; mean birth weight 2502 gm) with abnormal pneumographic results were randomly allocated to receive theophylline or placebo. The control group consisted of 94 healthy age- and weight-matched infants. After four weeks of treatment infants in the theophylline group had a significantly lower incidence (2.1% vs. 4.3%) and density of apnoeas > or = 15 sec (0.001 vs. 0.003). There were significantly less short apnoeas (> or = 6 sec.) in theophylline treated than in control infants (p < 0.01). The number of periodic breathing episodes showed a significant, presumably age-related reduction in both treatment groups. We conclude that theophylline is an effective agent in reducing the incidence and duration of apnoeas beyond what would be expected from age-related maturation of breathing.

Modafinil in obstructive sleep apnea-hypopnea syndrome: a pilot study in 6 patients

We studied the effects of modafinil, a vigilance-enhancing drug, on excessive daytime sleepiness, memory, night sleep and respiration in 6 patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) using a double-blind random cross-over design with 24-hour polysomnography, verbal memory test and a 5-week sleep-wake diary kept by the patients. There were two 2-week treatment periods in which either modafinil or placebo was used; they were separated by a 1-week wash-out period. Our results show that modafinil reduces daytime sleep duration, lengthens the duration of subjective daytime vigilance and improves long-term memory in patients with OSAHS without modifying night sleep and respiration events.

Pressure-heart rate responses to alpha-adrenergic stimulation and hormonal regulation in normotensive patients with obstructive sleep apnea

Seven normotensive untreated patients with obstructive sleep apnea (OSA) and five control subjects without OSA were compared. Patients with cardiac dilation, chronic airflow limitation, liver and kidney disease, or diabetes mellitus were excluded. Change in pressure-heart rate relation to alpha-adrenergic stimulation (P-HRR), extracellular volume (ECV), and plasma volume (Vp) were measured during daytime. Plasma atrial natriuretic peptide (ANP), plasma renin and aldosterone concentrations were obtained at 1 hour intervals during the night. A mean apnea/hypopnea index (AHI) of 52.2 +/- 23.9/h and a mean lowest arterial oxygen saturation (SaO2) of 61.2 +/- 19.3% (mean +/- SD) were determined from polysomnographic monitoring in the patient group. Release of ANP was significantly higher during sleep in OSA patients than in control subjects (P < .01), with a maximum concentration between 4 and 6 AM in the former. Daytime ECV was significantly higher (P < .05) and Vp significantly lower (P < .05) in OSA patients. Night maximum concentration of ANP (max ANP) was negatively related to AHI (P < .05). P-HRR was negatively related to AHI (P < .05) and positively related to max ANP (P < .05). In conclusion, OSA syndrome alters hormonal system control of body fluid compartment regulation. The decreased response in night max ANP secretion in the most severe OSA patients could be explained by the smaller Vp observed in these patients, decreasing atrial and ventricular pressure loading. Furthermore, alteration of P-HRR, correlated to AHI and max ANP, strengthens the hypothesis that patients who develop hypertension are those in whom the protective mechanism of ANP release failed.

Reversal of central sleep apnea with oxygen

OBJECTIVE

To examine the effect of oxygen on apneas and sleep quality in patients with frequent central apneas during sleep.

DESIGN/SUBJECTS

Prospective intervention study of 20 consecutive patients with predominant central apnea identified from 570 patients referred for suspected sleep apnea syndrome. Sixteen patients had congestive heart failure and seven of them had a previous stroke. Three of the remaining four patients without heart failure had experienced a previous stroke, and one was being treated with morphine.

SETTING

The Department of Pulmonary Medicine at Umeå (Sweden) University Hospital.

INTERVENTIONS

The patients were investigated for one night receiving nasal oxygen and one night without it.

MEASUREMENTS

Overnight polysomnography with transcutaneous PCO2 and arterial blood gases.

RESULTS

Central apneas occurred during Cheyne-Stokes respiration in 18 of 20 patients and two patients had idiopathic central apneas. Without oxygen, the median number of all central apneas and hypopneas was 33.5 (range, 8.0 to 52.0) per hour of sleep. These episodes decreased to 5.0 (range, 0.0 to 31.0)(p < 0.01) during oxygen therapy. In 17 of 20 patients, the frequency of central apneas was reduced by more than 50%. Central apneas were reduced by oxygen irrespective of the presence or absence of heart failure or Cheyne-Stokes respiration. The arousal frequency was reduced during oxygen treatment. Daytime sleepiness, difficulty falling asleep, snoring, and self-scored awakenings were reduced in seven patients who were given nocturnal oxygen at home. Obstructive and mixed apneas were unaffected by oxygen.

CONCLUSIONS

Oxygen effectively reduces central sleep apnea in eucapnic patients.

Central sleep apnea-hypopnea syndrome in heart failure: prevalence, impact, and treatment

Despite recent advances in its treatment, congestive heart failure associated with depressed left ventricular function continues to be associated with excess morbidity and mortality. Multiple factors may contribute to the progressively declining course of heart failure. Nocturnal arterial oxyhemoglobin desaturation caused by sleep-disordered breathing could be a contributing factor, particularly because it has been associated with excess mortality in patients with chronic obstructive pulmonary disease. Cheyne and Stokes were the first to observe periodic breathing in patients with heart failure (Cheyne-Stokes respiration). However, relatively large-scale systematic studies have been performed only recently. We studied 42 patients with stable, optimally treated heart failure, without other co-morbid disorders: 19 patients (45%) had an apnea-hypopnea index of more than 20/hour. These episodes were associated with an excess number of arousals and arterial oxyhemoglobin desaturation. Treatment options include nocturnal administration of oxygen, continuous positive airway pressure (CPAP), and medications such as theophylline. Large-scale studies are needed to evaluate the efficacy of these treatment options on quality of life, morbidity, and mortality of patients with heart failure.

Is sleep apnea a predisposing factor for tobacco use?

We present a plausible and powerful explanation for nicotine addiction that is consistent with recent findings. Sleep apnea, the periodic cessation of breathing during sleep, may be responsible for the addictive nature of nicotine. The main symptoms of sleep apnea are somnolence and obesity. Nicotine has been shown to decrease these two symptoms as well as reduce the frequency and duration of apneas. When an apneic youth uses tobacco, the nicotine may begin to treat the apnea and reduce the symptoms. The response of the human system is, naturally, to continue that which improves life, assuring addiction of the apnea to the nicotine. Many of the illnesses attributed to tobacco use and passive parental smoking may actually be confounded by the inherited influence of sleep apnea. Treating the apnea may be a necessary precondition for a successful tobacco cessation program. Understanding the apnea-tobacco relationship may be an important step in the development of a tobacco prevention program for youth.

Management of simple snoring, upper airway resistance syndrome, and moderate sleep apnea syndrome

The spectrum of respiratory sleep disorders has been extended in the last years to include conditions that are less well defined than severe obstructive sleep apnea (OSA). Moderate OSA, snoring, and upper airway resistance syndrome (UARS) represent three conditions in which there are still unresolved pathophysiological, epidemiological, and clinical questions. Therefore, the therapeutic approach remains unclear. We have tried to define these entities and to review the respective indications and efficacy of pharmacological treatment, weight loss, sleep posture, oral appliances, upper airway surgery, and finally, continuous positive airway pressure (CPAP). From these data, we also aim to define strategies of treatment for moderate OSA, snoring, and UARS. However, these conditions are likely to be particularly appropriate for randomized trials comparing different modalities of treatment that may be the only way to validate these treatment strategies.

Effect of theophylline on sleep-disordered breathing in heart failure

BACKGROUND

Theophylline has been used to treat central apnea associated with Cheyne-Stokes respiration (periodic breathing). We studied the effect of short-term oral theophylline therapy on periodic breathing associated with stable heart failure due to systolic dysfunction.

METHODS

Fifteen men with compensated heart failure (left ventricular ejection fraction, 45 percent or less) participated in the study. Their base-line polysomnograms showed periodic breathing, with more than 10 episodes of apnea and hypopnea per hour. In a double-blind crossover study, the patients received theophylline or placebo orally twice daily for five days, with one week of washout between the two periods.

RESULTS

After five days of treatment, the mean (+/-SD) plasma theophylline concentration was 11 +/- 2 microgram per milliliter. Theophylline therapy resulted in significant decreases in the number of episodes of apnea and hypopnea per hour (18 +/- 17, vs. 37 +/- 23 with placebo and 47 +/- 21 at base line; P<0.001), the number of episodes of central apnea per hour (6 +/- 14, vs. 26 +/- 21 and 26 +/- 20, respectively; P<0.001), and the percentage of total sleep time during which the arterial oxyhemoglobin saturation was less than 90 percent (6 +/- 11 percent, vs., 23 +/- 37 and 14 +/- 14 percent, respectively; P<0.04). There were no significant differences in the characteristics of sleep, the frequency of ventricular arrhythmias, daytime arterial-blood gas values, or the left ventricular ejection fraction during the base-line, placebo, and theophylline phases of the study.

CONCLUSIONS

In patients with stable heart failure, oral theophylline therapy reduced the number of episodes of apnea and hypopnea and the duration of arterial oxyhemoglobin desaturation during sleep.

Hydralazine reduces elevated sleep apnea index in spontaneously hypertensive (SHR) rats to equivalence with normotensive Wistar-Kyoto rats

The effects of lowering blood pressure (BP) by hydralazine (HY) (2 mg/kg) on spontaneous (SA) and post-sigh (PSA) sleep apneas have been studied in spontaneously hypertensive (SHR) rats by monitoring their respiration and sleep by the EEG for 6 hours. Normotensive Wistar-Kyoto (WKY) rats, from which the SHR rat strain was derived, were used as an appropriate control. The SHR rats had more SA (p < 0.02) and PSA (p < 0.0001) apneas/hour than WKY rats during nonrapid eye movement sleep and their mean BP was higher by 40 mm Hg (p < 0.0001) than WKY rats. Administration of HY to SHR rats equalized their BP with the arterial pressure of WKY rats and reduced the SA and the PSA apneas/hour to equivalence with WKY normotensive rats. These results demonstrate that even in the context of lifelong hypertension, acute normalization of BP significantly reduces sleep apneas in rats. They further suggest that improved management of BP may be clinical benefit to patients with apnea who have long-standing hypertension.

A double-blind, randomized trial of sabeluzole--a putative glutamate antagonist--in obstructive sleep apnea

The effect of sabeluzole (SAB), an agent with anti-excitatory amino acid activity, on sleep, breathing and daytime symptoms was investigated in 13 patients with obstructive sleep apnea (OSA). There was marked interindividual variation in both the effect on sleep and breathing and the plasma concentration of SAB. However, individual plasma drug concentration was highly correlated (r = 0.82, p = 0.02) with a reduction of the oxygen desaturation index during sleep (ODI) after treatment with SAB. Further investigation of this and agents of this type are warranted in patients with OSA.

Kinetics of theophylline in apnea of prematurity in small for gestational age babies

OBJECTIVES

To study the pharmacokinetics of theophylline and its correlations to pharmacodynamic effects in apnea of prematurity in small for gestational age babies.

DESIGN

Prospective case control study.

SETTING

Level III Neonatal Intensive Care Unit.

SUBJECTS

Ten small for gestational age (SGA) babies and 10 gestation matched appropriate for gestational age (AGA) babies with recurrent apnea of prematurity.

METHODS

All babies were investigated to exclude secondary causes of apnea. 5 mg/kg of aminophylline loading dose followed by 2 mg/kg as maintenance dose every 8 hourly intravenously was used. The trough and peak levels of theophylline were assessed on different days of therapy. Clinical monitoring was done for the efficacy and toxicity of the drug. Analysis was done using unpaired Student's 't' test and the correlation between plasma theophylline levels of different days was performed by using ANOVA.

RESULTS

The therapeutic drug levels were achieved within 24 hours in all babies. The SGA babies showed 25% higher drug levels as compared to AGA babies. The mean trough plasma theophylline levels ranged from 8.15 +/- 1.59 to 12.37 +/- 1.54 micrograms/ml in SGA babies while in AGA babies they ranged from 6.26 +/- 1.93 to 9.96 +/- 1.96 micrograms/ml in first 8 days of therapy. The mean peak levels in SGA babies ranged from 11.91 +/- 1.84 to 17.13 +/- 1.63 micrograms/ml and in AGA babies ranged from 8.17 +/- 1.84 to 13.02 +/- 1.48 micrograms/ml. Twenty per cent SGA and AGA babies each developed clinical toxicity though toxic drug levels were found in 50% SGA and 30% AGA babies.

CONCLUSION

There is a need to modify dosage schedule for these babies.

Improvement of epileptic seizure control with treatment of obstructive sleep apnoea

Sleep deprivation increases the risk of recurrent seizures in epileptic patients. We identified 10 patients with recurrent seizures and sleep disruption related to obstructive sleep apnoea. Two patients were treated with positional therapy and the remaining eight patients were treated with continuous positive airway pressure. Three of the patients became seizure free and a fourth patient had a greater than 95% reduction in seizure frequency following only the initiation of therapy for the sleep apnoea. Three of these four patients responding to therapy, had a state-dependent seizure pattern. Two of the four responders did not exhibit the typical body habitus for obstructive sleep apnoea. Three additional patients improved in seizure frequency with change in anticonvulsant medication and treatment of the obstructive sleep apnoea. The remaining three patients had less than 50% reduction in seizure frequency with treatment of the obstructive sleep apnoea. These results indicate sleep disruption caused by sleep apnoea may increase the seizure frequency in some epileptic patients. Regardless of body habitus, epilepsy patients should be questioned carefully for a history of sleep disturbance and state dependence to their seizures. Treatment of sleep disorders in this population may lower the frequency of recurrent seizures.

p-SPA, a peripheral adenosine A1 analogue, reduces sleep apneas in rats

The actions of N6-p-sulfophenyladenosine (p-SPA), a novel peripherally selective adenosine A1 agonist, were assessed on spontaneous and postsigh central sleep apneas in freely moving, unanesthetized rats by simultaneously monitoring sleep and respiration. Intraperitoneal administration of 0.1, 0.3, and 1.0 mg/kg of the drug significantly decreased postsigh and spontaneous sleep apnea index (AI). This effect persisted throughout the 6-h recording period. Doses of 0.1 and 0.3 mg/kg did not affect sleep efficiency, whereas 1.0 mg/kg of p-SPA reduced it to 60% of baseline value.

Chronic alveolar hypoventilation: a review for the clinician

Chronic alveolar hypoventilation may present in an insidious fashion with nonspecific manifestations. The clinician should be aware of the potential for developing this condition in patients with certain thoracic and systemic diseases. Once chronic alveolar hypoventilation is confirmed with arterial blood gas analysis, a systematic evaluation can often point to the underlying etiology. As sleep in affected individuals is often associated with marked worsening of gas exchange and may also contribute to worsening daytime cardiopulmonary dysfunction, polysomnography is often indicated to determine the severity of nocturnal aberrations and to look for coexistent obstructive sleep apnea. Therapy of chronic alveolar hypoventilation often focuses on elimination of the nocturnal deterioration in gas exchange, and recent applications of noninvasive positive pressure ventilation during sleep have proven useful in the management of individuals with obesity-hypoventilation syndrome, restrictive thoracic disorders, neuromuscular diseases and central causes for hypoventilation. It is unclear whether wide-spread application of nocturnal ventilatory support to patients with chronic ventilatory failure due to chronic obstructive pulmonary disease is of long-term benefit.