Drug may aid sleep apnea symptoms at high altitude
By Genevra Pittman
NEW YORK | Tue Dec 11, 2012 4:05pm EST
(Reuters Health) - People with sleep apnea can safely travel to high altitudes with the help of a diuretic and a commonly used breathing device, a new study from Switzerland suggests.
Researchers found acetazolamide (sold as Diamox), which is already used to treat mountain sickness, improved overnight oxygen levels among people with the sleep disorder who spent time above 8,000 feet.
People who have sleep apnea stop breathing for short spurts when their airway collapses or gets blocked while they're asleep. The condition is most common among middle-aged, overweight adults and has been tied to a range of cardiovascular problems.
Because there is less oxygen in the air at high altitude, nighttime breathing symptoms may get worse far above sea level. However, there aren't any standard recommendations for mountain travelers with sleep apnea, according to Dr. Konrad Bloch, who worked on the new study.
"Physicians had no scientific evidence to counsel the patients," Bloch, from the University Hospital of Zurich, told Reuters Health.
To try to provide some guidance, his team sent 51 people with sleep apnea - all of whom lived at low altitude - to resorts in the Swiss Alps as high as 8,497 feet on two different trips.
Each time, the volunteers used a breathing device commonly prescribed to people with sleep apnea, called continuous positive airway pressure therapy, or CPAP, at night.
On one trip, participants also took three 250-milligram doses of acetazolamide each day. On the other, they were given drug-free placebo pills.
The dose of acetazolamide used here costs about $1.10 to $1.50 daily, the researchers noted. Along with being a diuretic, acetazolamide also triggers more frequent breathing.
Bloch and his colleagues found participants' average oxygen saturation overnight - a measure of sleep apnea severity - was better among the acetazolamide group, at 91 percent versus 89 percent in the placebo group at the highest altitude. (Normal oxygen saturation is between 97 and 99 percent.)
People taking acetazolamide also stopped breathing fewer times during the night than those taking the placebo pills, the research team reported Tuesday in the Journal of the American Medical Association.
With the type of CPAP used here, called autoCPAP, a computer controls air pressure flowing through the breathing mask. For standard CPAP - which is more common in the United States - pressure is calibrated in a sleep lab and doesn't change based on nightly variation.
Most of the study volunteers were moderately obese men. Any related conditions they had - such as diabetes or high blood pressure - were stable before the study.
WATCH FOR SIDE EFFECTS
Bloch said acetazolamide, which requires a prescription, "is not a harmless drug" because it alters water and salt content in the body. Some people in the study had side effects such as burning, numbness or tingling - and others complained about the drug's taste.
For patients with heart or kidney disease in addition to sleep apnea, acetazolamide could lead to more serious complications - by making them pee too much, said Dr. Seva Polotsky, a sleep apnea researcher from Johns Hopkins University School of Medicine in Baltimore.
"I think it's really beneficial. Having said that, you have to be careful with this drug," Polotsky, who wasn't involved in the new study, told Reuters Health.
"I would definitely check with a doctor and approach it very carefully."
The new research was partially funded by a grant from Philips Respironics, which markets sleep systems such as CPAP devices.
Bloch and Polotsky both recommended anyone traveling at altitude ascend slowly and take time to acclimatize along the way.
"This is a recommendation that is important for everyone, but especially those that have a breathing problem," Bloch said.
SOURCE: bit.ly/JjFzqx Journal of the American Medical Association, online December 11, 2012.
Effect of Acetazolamide and AutoCPAP Therapy on Breathing Disturbances Among Patients With Obstructive Sleep Apnea Syndrome Who Travel to Altitude
A Randomized Controlled Trial
Tsogyal D. Latshang, MD; Yvonne Nussbaumer-Ochsner, MD; Rahel M. Henn, BMS; Silvia Ulrich, MD; Christian M. Lo Cascio, MD; Bruno Ledergerber, PhD; Malcolm Kohler, MD; Konrad E. Bloch, MD
JAMA. 2012;308(22):2390-2398. doi:10.1001/jama.2012.94847.
Context Many patients with obstructive sleep apnea syndrome (OSA) living near sea level travel to altitude, but this may expose them to hypoxemia and exacerbation of sleep apnea. The treatment in this setting is not established.
Objective To evaluate whether acetazolamide and autoadjusted continuous positive airway pressure (autoCPAP) control breathing disturbances in OSA patients at altitude.
Design, Setting, and Participants Randomized, placebo-controlled, double-blind, crossover trial involving 51 patients with OSA living below an altitude of 800 m and receiving CPAP therapy who underwent studies at a university hospital at 490 m and resorts in Swiss mountain villages at 1630 m and 2590 m in summer 2009.
Interventions Patients were studied during 2 sojourns of 3 days each in mountain villages, 2 days at 1630 m, 1 day at 2590 m, separated by a 2-week washout period at less than 800 m. At altitude, patients either took acetazolamide (750 mg/d) or placebo in addition to autoCPAP.
Main Outcome Measures Primary outcomes were nocturnal oxygen saturation and the apnea/hypopnea index; secondary outcomes were sleep structure, vigilance, symptoms, adverse effects, and exercise performance.
Results Acetazolamide and autoCPAP treatment was associated with higher nocturnal oxygen saturation at 1630 m and 2590 m than placebo and autoCPAP: medians, 94% (interquartile range [IQR], 93%-95%) and 91% (IQR, 90%-92%) vs 93% (IQR, 92%-94%) and 89% (IQR, 87%-91%), respectively. Median increases were 1.0% (95% CI, 0.3%-1.0%) and 2.0% (95% CI, 2.0%-2.0). Median night-time spent with oxygen saturation less than 90% at 2590 m was 13% (IQR, 2%-38%) vs 57% (IQR, 28%-82%; P < .001). Acetazolamide and autoCPAP resulted in better control of sleep apnea at 1630 m and 2590 m than placebo and autoCPAP: median apnea/hypopnea index was 5.8 events per hour (5.8/h) (IQR, 3.0/h-10.1/h) and 6.8/h (IQR, 3.5/h-10.1/h) vs 10.7/h (IQR, 5.1/h-17.7/h) and 19.3/h (IQR, 9.3/h-29.0/h), respectively; median reduction was 3.2/h (95% CI, 1.3/h-7.5/h) and 9.2 (95% CI, 5.1/h-14.6/h).
Conclusion Among patients with OSA spending 3 days at moderately elevated altitude, a combination of acetazolamide and autoCPAP therapy, compared with autoCPAP alone, resulted in improvement in nocturnal oxygen saturation and apnea/hypopnea index.
Traveling to High Altitude When You Have Sleep Apnea FREE
Tsogyal D. Latshang, MD; Konrad E. Bloch, MD; Cassio Lynm, MA; Edward H. Livingston, MD
JAMA. 2012;308(22):2418. doi:10.1001/jama.2012.4097.
What is the best way to manage sleep apnea when traveling to high altitude? A study published in the December 12, 2012, issue of JAMA reports treatments to minimize the risk of altitude-related illness for patients with sleep apnea. At altitude, the reduced oxygen content of the blood induces breathing instability, with periods of deep and rapid breathing alternating with central apnea. This breathing pattern is called high-altitude periodic breathing. It occurs even in healthy persons at altitudes above 6000 ft. It may lead to sleep disturbances with frequent awakenings and a feeling of lack of air.
High-altitude periodic breathing in healthy mountain travelers and in patients with preexisting obstructive sleep apnea can be prevented or treated with acetazolamide, a drug that is also used for acute mountain sickness.
Travelers to high altitude (>2500 m/>8000 ft above sea level) should ascend slowly and drink sufficient amounts of water. Sleeping altitude should be as low as possible. People with a history of severe altitude sickness should consult their doctor regarding the use of acetazolamide before traveling to a high altitude.
Patients with obstructive sleep apnea who travel to high altitude should continue to use their CPAP machine while traveling as they do at home. Such patients might benefit from preventive treatment with acetazolamide when staying at an altitude higher than 1600 m; they should consult their doctor about this possibility.
Patients with obstructive sleep apnea who do not use CPAP should consult with their doctor before traveling to high altitude about the potential use of CPAP and acetazolamide or a dental appliance.
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