Medical therapy of obstructive sleep apnea

Drug therapy for obstructive sleep apnoea in adults

BACKGROUND

The treatment of choice for moderate to severe obstructive sleep apnoea (OSA) is continuous positive airways pressure (CPAP) applied via a mask during sleep. However, this is not tolerated by all individuals and its role in mild OSA is not proven. Drug therapy has been proposed as an alternative to CPAP in some patients with mild to moderate sleep apnoea and could be of value in patients intolerant of CPAP. A number of mechanisms have been proposed by which drugs could reduce the severity of OSA. These include an increase in tone in the upper airway dilator muscles, an increase in ventilatory drive, a reduction in the proportion of rapid eye movement (REM) sleep, an increase in cholinergic tone during sleep, an increase in arousal threshold, a reduction in airway resistance and a reduction in surface tension in the upper airway.

OBJECTIVES

To determine the efficacy of drug therapies in the specific treatment of sleep apnoea.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials. Searches were current as of July 2012.

SELECTION CRITERIA

Randomised, placebo controlled trials involving adult patients with confirmed OSA. We excluded trials if continuous positive airways pressure, mandibular devices or oxygen therapy were used. We excluded studies investigating treatment of associated conditions such as excessive sleepiness, hypertension, gastro-oesophageal reflux disease and obesity.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by The Cochrane Collaboration.

MAIN RESULTS

Thirty trials of 25 drugs, involving 516 participants, contributed data to the review. Drugs had several different proposed modes of action and the results were grouped accordingly in the review. Each of the studies stated that the participants had OSA but diagnostic criteria were not always explicit and it was possible that some patients with central apnoeas may have been recruited.Acetazolamide, eszopiclone, naltrexone, nasal lubricant (phosphocholinamine) and physiostigmine were administered for one to two nights only. Donepezil in patients with and without Alzheimer's disease, fluticasone in patients with allergic rhinitis, combinations of ondansetrone and fluoxetine and paroxetine were trials of one to three months duration, however most of the studies were small and had methodological limitations. The overall quality of the available evidence was low.The primary outcomes for the systematic review were the apnoea hypopnoea index (AHI) and the level of sleepiness associated with OSA, estimated by the Epworth Sleepiness Scale (ESS). AHI was reported in 25 studies and of these 10 showed statistically significant reductions in AHI.Fluticasone in patients with allergic rhinitis was well tolerated and reduced the severity of sleep apnoea compared with placebo (AHI 23.3 versus 30.3; P < 0.05) and improved subjective daytime alertness. Excessive sleepiness was reported to be altered in four studies, however the only clinically and statistically significant change in ESS of -2.9 (SD 2.9; P = 0.04) along with a small but statistically significant reduction in AHI of -9.4 (SD 17.2; P = 0.03) was seen in patients without Alzheimer's disease receiving donepezil for one month. In 23 patients with mild to moderate Alzheimer's disease donepezil led to a significant reduction in AHI (donepezil 20 (SD 15) to 9.9 (SD 11.5) versus placebo 23.2 (SD 26.4) to 22.9 (SD 28.8); P = 0.035) after three months of treatment but no reduction in sleepiness was reported. High dose combined treatment with ondansetron 24 mg and fluoxetine 10 mg showed a 40.5% decrease in AHI from the baseline at treatment day 28. Paroxetine was shown to reduce AHI compared to placebo (-6.10 events/hour; 95% CI -11.00 to -1.20) but failed to improve daytime symptoms.Promising results from the preliminary mirtazapine study failed to be reproduced in the two more recent multicentre trials and, moreover, the use of mirtazapine was associated with significant weight gain and sleepiness. Few data were presented on the long-term tolerability of any of the compounds used.

AUTHORS' CONCLUSIONS

There is insufficient evidence to recommend the use of drug therapy in the treatment of OSA. Small studies have reported positive effects of certain agents on short-term outcomes. Certain agents have been shown to reduce the AHI in largely unselected populations with OSA by between 24% and 45%. For donepezil and fluticasone, studies of longer duration with a larger population and better matching of groups are required to establish whether the change in AHI and impact on daytime symptoms are reproducible. Individual patients had more complete responses to particular drugs. It is possible that better matching of drugs to patients according to the dominant mechanism of their OSA will lead to better results and this also needs further study.

Long-term follow-up of patients operated with Uvulopalatopharyngoplasty from 1985 to 1991

OBJECTIVES

Short-term outcome and side effects after Uvulopalatopharyngoplasty (UPPP) are well recognized. However, there is a lack of knowledge of the long-term outcome and side effects after this surgery. This study was completed to investigate the outcome and side effects 20 years after UPPP for snoring and obstructive sleep apnoea.

METHODS

Medical records of patients who underwent UPPP surgery for sleep apnoea and snoring between 1985 and 1991 were investigated retrospectively. A specific questionnaire focusing on the present health profile, side effects of previous UPPP surgery and present sleeping patterns of patients was mailed out.

RESULTS

UPPP patients, 186 (including 11 females) were identified. Of these, 35 (19%) had passed away and 7 (4%) were not located. 129 patients (mean: age 68 years, range 43-83) of the possible 144 patients answered the questionnaire (response rate 90%). At follow-up, 41 patients (32%) used continuous positive airway pressure (CPAP). 66 of the patients (52%) were satisfied with the result of the operation, but 61 (47%) were not satisfied. 49 patients (38%) reported persistent side effects (problems with nasal regurgitation 18 (14%), swallowing 26 (20%), changed voice 15 (12%), and pain in the oral cavity 15 (12%).

CONCLUSION

Almost 50% of patients operated with UPPP were not satisfied with the result of the operation after about 20 years, and one third used CPAP at follow-up. A large proportion of patients still experienced side effects, which, after this time, are likely to be permanent.

Drug therapy for obstructive sleep apnoea in adults

BACKGROUND

The treatment of choice for moderate to severe obstructive sleep apnoea (OSA) is continuous positive airways pressure (CPAP) via a mask during sleep. However this is not tolerated by all patients and its role in mild OSA is not proven. Drug therapy has been proposed as an alternative to CPAP in some patients with mild to moderate sleep apnoea and could be of value in patients intolerant of CPAP. A number of mechanisms have been proposed by which drugs could reduce the severity of OSA. These include an increase in tone in the upper airway dilator muscles, an increase in ventilatory drive, a reduction in the proportion of REM sleep, an increase in cholinergic tone during sleep, a reduction in airway resistance and a reduction in surface tension in the upper airway.

OBJECTIVES

To determine the efficacy of drug therapies in the treatment of sleep apnoea.

SEARCH STRATEGY

We carried out searches on the Cochrane Airways Group Specialised Register of trials. Searches were current as of July 2005.

SELECTION CRITERIA

Randomised, placebo controlled trials involving adult patients with confirmed OSA . We excluded trials if continuous positive airways pressure, mandibular devices or oxygen therapy were used. No restriction was placed upon publication language or trial duration.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed studies for inclusion, undertook data extraction according to pre-specified entry criteria, and quality assessment of studies. No response for further information was forthcoming from study authors. Results were expressed as mean differences and 95% Confidence Intervals (CI).

MAIN RESULTS

Twenty-six trials of 21 drugs, involving 394 participants contributed data to the review. Most of the studies were small and many trials had methodological limitations. Each of the studies states that the subjects had OSA but diagnostic criteria were not always explicit and it is possible that some patients with central apnoeas may have been recruited. Six drugs had some impact on OSA severity and two altered daytime symptoms. One study reported that apnoea hypopnea index (AHI) was lower following treatment with intranasal fluticasone compared with placebo (23.3 versus 30.3) in 24 participants with sleep apnoea and rhinitis. Subjective alertness in the daytime also improved. Physostigmine gave an AHI of 41 compared to 54 on placebo (10 participants) and in a similar study Mirtazipine 15 mg produced an AHI of 13 compared to 23.7 for placebo (10 participants). Topical nasal lubricant given twice overnight resulted in an AHI of 14 compared to 24 with placebo (10 participants). These three latter studies were of single night crossover design and so there are no data on the acceptability of these treatments or their effect on symptoms. Paroxetine was shown to reduce AHI to 23.3 compared to 30.3 for placebo, most of the 20 participants tolerated the treatment but there was no improvement in daytime symptoms. Acetazolamide also reduced the AHI (one crossover trial of nine patients, mean difference 24 (95% CI 4 to 44). However there was no symptomatic benefit from the drug and it was poorly tolerated in the long term. Protriptyline led to a symptomatic improvement (improved versus not improved) in two out of three crossover trials (13 participants, Peto Odds Ratio 29.2 (95% CI 2.8 to 301.1) but there was no change in the apnoea frequency. In one trial naltrexone did reduce AHI, but total sleep time favoured placebo. No significant beneficial effects were found for medroxy progesterone, clonidine, mibefradil, cilazapril, buspirone, aminophylline, theophylline doxapram, ondansetron or sabeluzole.

AUTHORS' CONCLUSIONS

There is insufficient evidence to recommend the use of drug therapy in the treatment of OSA. Small studies have reported positive effects of certain agents on short-term outcome. Certain agents have been shown to reduce the AHI in largely unselected populations with OSA by between 24 and 45%. For fluticasone, mirtazipine, physostigmine and nasal lubricant, studies of longer duration are required to establish whether this has an impact on daytime symptoms. Individual patients had more complete responses to particular drugs. It is likely that better matching of drugs to patients according to the dominant mechanism of their OSA will lead to better results and this also needs further study.

Progesterone reverses the neuronal responses to hypoxia in rat nucleus tractus solitarius in vitro

The nucleus tractus solitarius (NTS) is a relay nucleus that integrates peripheral chemoreceptor input in response to hypoxia and hence influences the generation of respiratory rhythm. Several studies have shown that administration of progesterone stimulates ventilatory responses to hypoxia. There is some evidence that this steroid hormone can act at the level of the arterial peripheral chemoreceptors, whereas its action in the central nervous system remains unclear. To investigate a possible central involvement during hypoxia, we studied the effect of progesterone on neuronal activities recorded extra- and intracellularly in the NTS using brainstem slices. Central chemosensitivity was tested by comparing synaptic activity and intrinsic electro-responsiveness of 38 neurones during normoxia and hypoxia. In more than two-thirds of neurones recorded, hypoxia elicited a hyperpolarisation, a decrease in the input resistance and a decrease in spontaneous activity. In the remaining neurones (n = 12) hypoxia elicited a depolarisation and an increase in spontaneous activity. In all neurones tested, synaptic potentials evoked by stimulation of the tractus solitarius were decreased by hypoxia. While progesterone (1 microM) had no effect under normoxic conditions, it partially reversed all hypoxic neuronal responses. This effect developed over 2-3 min and reversed within 5 min suggesting a non-genomic mechanism of action. Taken together these results suggest that progesterone interacts with the hypoxia-induced cellular signalling. We conclude that in the NTS, transmission of afferent signals is reduced by hypoxia and restored by progesterone administration. Such a mechanism may contribute to the stimulation of breathing in response to hypoxia observed following progesterone administration in vivo.

Drug treatments for obstructive sleep apnoea

BACKGROUND

The treatment of choice for moderate to severe obstructive sleep apnoea (OSA) is continuous positive airway pressure (CPAP) via a mask during sleep. However this is not tolerated by all patients and its role in mild OSA is not proven. Drug therapy has been proposed as an alternative to CPAP in some patients with mild to moderate sleep apnoea. The mechanisms by which drugs might reduce OSA include; a reduction in the proportion of rapid eye movement (REM) sleep (during which apnoeas tend to be more frequent), an increase in ventilatory drive or an increase in upper airway muscle tone during sleep.

OBJECTIVES

To determine the efficacy of drug therapies in the treatment of sleep apnoea.

SEARCH STRATEGY

Searches were carried out on the Cochrane Airways Group RCT Register. Additional hand searching was performed as relevant.

SELECTION CRITERIA

Double blind, randomised placebo controlled trials were included, involving patients with confirmed obstructive sleep apnoea. Trials were excluded if continuous positive airways pressure, mandibular devices or oxygen therapy were used. No restriction was placed upon publication language or trial duration.

DATA COLLECTION AND ANALYSIS

A total of 51 references were identified by electronic searches. 42 studies were retrieved for selection and 9 trials were included in the review. The results for 91 patients were available. No response for further information was forthcoming from the study authors. Results were expressed as (WMD) and 95% Confidence Intervals (95% CI) MAIN RESULTS: Only acetazolamide reduced the Hypopnoea Index (1 crossover trial of 9 patients, Weighted Mean Difference -24; 95%Confidence Intervals (95% CI): -4, -44). However there was no symptomatic response and the drug was poorly tolerated. Protriptyline led to a symptomatic improvement (improved vs not improved) in two out of three crossover trials (13 patients, Peto Odds Ratio 29.2; 95%CI 2.8, 301.1) but there was no change in the apnoea frequency. No beneficial effects were found for medroxy progesterone, clonidine, buspirone, aminophylline, theophylline or sabeluzole.

REVIEWER'S CONCLUSIONS

The data available do not support the use of drugs as a therapy for OSA. Although the studies examined had limitations there was little to justify further trials of these particular drugs.

Relationship of ovarian hormones to hypoxemia in women residents of 4,300 m

Prevalence of excessive erythrocytosis, the main sign of chronic mountain sickness (CMS), is greater in postmenopausal Andean women than in premenopausal women. It is uncertain whether this greater prevalence is related to the decline in female hormones and ventilatory function after the occurrence of the menopause. To study this, we compared the physiological variables involved in the physiopathology of CMS [end-tidal CO(2) (PET(CO(2)), Torr) and end-tidal O(2) (PET(O(2)), Torr), arterial oxygen saturation (Sa(O(2)), %), and Hb concentration (g/dl)] and progesterone and estradiol levels between postmenopausal and premenopausal women, both in the luteal and follicular phases. Women residing in Cerro de Pasco (n = 33; 4,300 m) aged 26--62 yr were studied. Postmenopausal women compared with premenopausal women in the luteal phase had lower PET(O(2)) (48 +/- 4 vs. 53 +/- 2 Torr, P = 0.005) and Sa(O(2)) levels (82 +/- 12 vs. 88 +/- 12%, P < 0.005) and higher PET(CO(2)) (34 +/- 2 vs. 29 +/- 3 Torr, P = 0.005) and Hb concentration (19 +/- 1 vs. 14 +/- 2 g/dl, P < 0.005). In addition, plasma progesterone was negatively correlated with PET(CO(2)) and positively correlated with PET(O(2)) and Sa(O(2)). No clear relationship was found among the cycle phases between estradiol and the variables studied. In conclusion, our results reveal that, before menopause, there is better oxygenation and lower Hb levels in women long residing at altitude, and this is associated with higher levels of progesterone in the luteal phase of the cycle.

Effect of short-term hormone replacement in the treatment of obstructive sleep apnoea in postmenopausal women

BACKGROUND

Women appear to be increasingly susceptible to snoring and sleep disordered breathing after the menopause. This observation, coupled with the considerable sex difference in sleep apnoea, may be explained on the basis of a protective effect of female hormones. This study was carried out to determine whether hormone replacement therapy has a role in the management of obstructive sleep apnoea in postmenopausal women.

METHODS

The effect of short-term (mean (SE) 50 (3) days) hormone replacement therapy with either oestrogen alone or in combination with progesterone on sleep disordered breathing was investigated in 15 postmenopausal women with moderate obstructive sleep apnoea. The effect of treatment on the ventilatory response to hypoxia and hypercapnia was assessed in 10 patients.

RESULTS

There was no reduction in the clinical severity of obstructive sleep apnoea after hormone treatment despite an increase in the serum oestrogen level from 172 (23) to 322 (33) pmol/l. There was a small but clinically insignificant reduction in the apnoea/hypopnoea index during REM sleep from 58 (6) to 47 (7). There was no difference in response between the oestrogen only group and the oestrogen plus progesterone group. Hypercapnic ventilatory responsiveness did not change with hormone treatment, but an change with hormone treatment, but an increase in hypoxic ventilatory responsiveness was observed.

CONCLUSIONS

These data indicate that short-term hormone replacement is unlikely to have an effective role in the clinical management of postmenopausal women with obstructive sleep apnoea. The observed reduction in the apnoea/hypopnoea index during REM sleep, however, suggests that longer term treatment, or the use of higher doses, may have an effect.

Pulmonary function and sleep disordered breathing in patients with traumatic tetraplegia: a longitudinal study

The purpose of this study was to determine longitudinal changes in nocturnal blood gas tensions in individuals with stable traumatic tetraplegia. Ten individuals initially evaluated at least 6 months postinjury were reevaluated 5 years later. When initially evaluated, all the patients had normal daytime blood gases. Six (60%), however, had nocturnal oxyhemoglobin desaturations (dSATs) below 90%, 3 (30%) had mean nocturnal oxyhemoglobin saturation (SAT) below 90% for 10% or more of at least 1 hour, and 4 had maximum end-tidal carbon dioxide tensions (EtCO2) greater than 45mmHg. At 5-year follow-up evaluation, then a mean of 11.6 +/- 5.7 years postinjury, the vital capacities (VCs) of these individuals had improved significantly by a mean of 1242 +/- 545mL without treatment, and daytime blood gases were still normal for 9 out of 10 patients. Five of the individuals (50%), however, had an increased number of transient nocturnal dSATs and 8 of 9 (88%) re-studied by capnography were hypercapnic. We conclude that nocturnal dSAT and hypercapnia appear to be common in tetraplegia and may increase as the patient ages, despite significant increases in VC. Oximetry and capnography are useful in diagnosing nocturnal dSAT and in monitoring treatment.

Nasal intermittent positive pressure ventilation in the treatment of respiratory failure in obstructive sleep apnoea

Severe respiratory failure in a patient with obstructive sleep apnoea was treated successfully with nasal intermittent positive pressure ventilation.

The sleep apnea syndrome. Part II: Treatment

An increase in the number of obstructive sleep apnea patients has brought a paralleled demand for timely and effective treatment. Conservative measures to maintain airway patency during sleep include weight loss, lateral decubitus sleep posture, drug therapy, nasal continuous positive airway pressure, and the use of intraoral prostheses. Surgical measures are used to correct gross anatomic defects that cause or contribute to obstruction, remove redundant tissues (uvulopalatopharyngoplasty), or provide an airway below the suspected area of obstruction (tracheostomy). Part II of this article examines the rationale, benefits, disadvantages, and potential complications of each modality of treatment.

Obstructive sleep apnoea during pregnancy requiring tracheostomy

The case is presented as an unusual example of the benefit of tracheostomy during pregnancy in a patient with obstructive sleep apnoea syndrome.

Nasal continuous positive airway pressure in Pneumocystis carinii pneumonia

10 cm H2O of nasal continuous positive airway pressure (CPAP) was applied in nine subjects with Pneumocystis carinii pneumonia and the acquired immunodeficiency syndrome, all of whom had presented with bilateral pulmonary infiltrates and hypoxaemia. The procedure was tolerated well by eight patients and none of the nine had complications. 20 minutes of nasal CPAP without supplemental oxygen increased mean PaO2 from 55.9 to 68.4 mm Hg and decreased the calculated alveolar-arterial oxygen gradient from 48.3 to 34.3 mm Hg. In one patient who was breathing oxygen at 4 litres per minute, PaO2 increased by 35 mm Hg. Nasal CPAP could be a useful method for augmenting oxygenation in P carinii pneumonia.

Low dose aminophylline selectively increases upper airway motor activity in normals

Because certain pharmacologic agents differentially influence upper airway and diaphragm motor activity, we postulated that the adenosine antagonist theophylline might preferentially increase alae nasi activity in human subjects. Using a double-blinded, randomized, placebo controlled design, we studied the effect of low dose aminophylline (1-2 mg/kg) on alae nasi and diaphragm surface electromyographic (EMG) activity. Seven healthy volunteers served as subjects for two trials on separate days. Subjects breathed from a close circuit while end tidal PCO2 was held constant in the eucapnic range. During each trial we recorded EMG signals from the alae nasi and diaphragm before and after intravenous infusion of either aminophylline or placebo. After the administration of aminophylline, the mean alae nasi EMG signal increased 87 +/- 31 (SD)% (P less than 0.005) while the mean diaphragmatic EMG signal did not change. There was no significant change in either the alae nasi or diaphragmatic EMG signal after placebo. There was no change in minute ventilation, tidal volume, or respiratory frequency after either aminophylline or placebo. We speculate that low dose aminophylline produces a selective increase in upper airway muscle activity through stimulation of the reticular activating system.

Sleep apnea in olivopontocerebellar degeneration: treatment with trazodone

A 37-year-old man with a 19-year history of progressive autosomal-dominant olivopontocerebellar degeneration developed excessive daytime sleepiness and paroxysmal episodes that clinically resembled an ictal or postictal state. Polysomnography showed sleep apnea. Long-term therapy with trazodone resulted in resolution of the paroxysmal episodes, disappearance of daytime sleepiness, and gradual improvement of sleep architecture over several months.