High-altitude Periodic Breathing Research Articles

1037 Central sleep apnea due to high altitude periodic breathing

Abstract Introduction Many popular tourist destinations are at high-altitude. Visitors commonly report poor sleep quality during the first few nights after arriving, but some do not resolve over time and daytime symptoms may develop that require medical attention. Report of case(s) A previously healthy 76-year-old American man presented with progressive fatigue and frequent nocturnal awakenings to a clinic in Bogota, Columbia (altitude 2640 meters), where he had been living for eighteen months during the COVID-19 pandemic lockdown due to limited ability to travel. An arterial blood gas on room air revealed hypocapnia with a partial pressure of CO2 of 25 mmHg. A polysomnography (PSG) performed in Bogota demonstrated an apnea-hypopnea index (AHI) of 98 events/hour consisting of predominately central as well as obstructive respiratory disturbances (Figure 1). After a titration study, he was placed on treatment with continuous positive airway pressure (CPAP) at 10 cmH2O along with oxygen 1 L/min, but he had difficulty acclimating to treatment. The patient presented to our institution two months after returning to the USA with significantly improved symptoms despite remaining off CPAP. Repeat PSG revealed a substantial reduction in the AHI at 15 events/hour consisting of only central respiratory disturbances in the supine position during transitional N1/N2 sleep (Figure 2). Positional therapy was recommended. A repeat home sleep study performed three months later to reassess disease severity during non-supine sleep showed resolution of respiratory disturbances (Figure 3). High-altitude periodic breathing is a common phenomenon, characterized by alternating periods of absent respiratory efforts with periods of hyperventilation without another etiology (1, 2). It occurs due to the interaction of hypocapnia and increased loop-gain (2). Central sleep apnea (CSA) is considered a disorder only when associated with symptoms, not simply due to an elevated central apnea index (3). The more rapid ascent and the higher the altitude, the greater risk of developing periodic breathing. Descending to a lower altitude will often resolve apnea after few days but the phenomenon can persist for up to months (2, 4) as our patient. Conclusion CSA develops commonly upon ascent to high altitude. When feasible, symptomatic patients should be encouraged to descend to a lower altitude. Support (if any)

0861 Sleepy in the Mountains

IntroductionCentral sleep apnea (CSA) is a rare disorder caused by a reduction of airflow and ventilatory effort during sleep. CSA is rarely idiopathic and associated with medical conditions including heart failure, opioid medications, treatment emergent and high-altitude periodic breathing. At higher altitudes, hypoxemia induces periodic breathing with periods of deep and rapid breathing alternating with central apnea. Patients with high-altitude periodic breathing experience fragmented sleep, poor sleep quality, excessive daytime sleepiness, morning headaches and witnessed apnea. We discuss a patient with obstructive sleep apnea (OSA) who developed new-onset central sleep apnea after relocating to a higher altitude location. Report of Cases: A 75-year-old male with a history of moderate obstructive sleep apnea well controlled on CPAP for eight years, with no known cardiovascular or pulmonary disease, presented with new-onset excessive daytime sleepiness. He had recently relocated to an area in the Colorado mountains (7000 ft elevation) from his previous home in Los Angeles (sea level). His residual apneahypopnea index (r-AHI) displayed on his CPAP machine increased to 7-14/hr from his normal of 1-2/hr after his relocation. Review of his compliance data revealed his central apnea index was elevated, contributing to his high r-AHI. A one-night nocturnal oximeter was mailed to the patient to use while on CPAP. Data revealed oxygen desaturation to less than 88% for about 2 hours of the night, worse during the early morning hours. The patient was advised to undergo a polysomnography and adaptive servo-ventilation titration if significant central sleep apnea was present. The patient declined due to concern about the COVID-19 pandemic. Supplemental nocturnal oxygen was initiated at 2L/min with normalization of the r-AHI.ConclusionPatients with OSA who experience worsening symptoms or increased r-AHI despite excellent compliance with PAP therapy should be considered for repeat polysomnography or titration study. While it is expected that high-altitude central sleep apnea will improve with acclimatization, nocturnal supplemental oxygen in addition to PAP therapy is indicated for patients with high-altitude central sleep apnea to diminish hypoxemia and improve residual AHI and sleep quality.Support (If Any)

Effect of acetazolamide on obstructive sleep apnoea in highlanders: protocol for a randomised, placebo-controlled, double-blinded crossover trial

IntroductionObstructive sleep apnoea (OSA) is a highly prevalent disease that causing systemic hypertension. Furthermore, altitude-dependent hypobaric hypoxic condition and Tibetan ethnicity have been associated with systemic hypertension independent of OSA,...

Effect of mild obstructive sleep apnea in mountaineers during the climb to Mount Aconcagua.

Objectiveto compare mountaineers with and without asymptomatic sleep apnea (OSA) before the ascent and to study high altitude-related sleep disorders, its interaction with metabolic, neuroendocrine and immunological components.Material and MethodsDuring an expedition to Mount Aconcagua, researchers assessed the respiratory polygraphy (RP), clinical condition and inflammatory parameters, and rhythm of cortisol secretion in mountaineers sleeping at different altitude camps.Results8 athletes (4 women), 36 years old (25-51) participated. Baseline and final BMI were; 23.6 (20.9-28.7) and 22.77 (20.9-27.7), respectively: p<0.01. 40 valid RP recordings were analyzed. At 746 m.a.s.l. (baseline), only 2 mountaineers presented mild asymptomatic OSA. The OSA group presented baseline apnea-hypopnea index (AHI) values between 5-15 events per hour, which evidence a mild respiratory sleep disorder with AHI increased by altitude depending of central apneas and hypopneas (p<0.05) as high altitude periodic breathing pattern but no increase in obstructive apneas (p<0.01). The circadian rhythm of cortisol was maintained in all cases in which they had not received treatment with dexamethasone and their values increased with the altitude reached. Increased systolic blood pressure was observed in the OSA group.ConclusionIn a context of hypobaric hypoxia, individuals with pre-existing asymptomatic OSA are prone to experiencing lower oxygen saturations and clinical deterioration.

Preparing for Mars: human sleep and performance during a 13 month stay in Antarctica

Manned spaceflights from Earth to Mars will likely become reality within the next decades. Humans will be exposed to prolonged isolation, confinement, and altered photoperiods under artificial atmospheric conditions, with potential adverse effects on sleep and performance. On Earth, polar environments serve as space analogs to study human adaptation; yet, few studies include polysomnography due to operational constraints. Polysomnography, self-reported sleepiness and fatigue, and psychomotor performance were measured every 6 weeks in 13 males ("Hivernauts") during a 13 month winter-over campaign at Concordia (Antarctica). Stability and robustness of interindividual differences were examined by means of intraclass correlations. Hivernauts present with high-altitude periodic breathing, increased sleep onset latencies, and reduced psychomotor speed. Except for obstructive apneas, all sleep, sleepiness, and psychomotor performance variables remain stable over time. Individual differences in respiratory variables show the highest degree of stability and robustness, followed by fatigue and situational sleepiness, sleep fragmentation, and psychomotor speed, suggesting moderate to substantial trait-like characteristics for these variables. Phase delays are suspected in Hivernauts, both in individuals with imposed and self-selected bedtimes. A significant decline in psychomotor speed over time is observed in the latter group. Space analog conditions such as isolated confinement, extreme photoperiods, and altered atmospheric conditions affect human sleep and performance. However, individual responses to these extreme environmental challenges show large differences and remain relatively stable under prolonged exposure. Ad hoc polysomnographic, including respiratory function monitoring is therefore recommended for selecting eligible candidates for extraterrestrial sojourns.

Adaptive Servoventilation as Treatment for Central Sleep Apnea Due to High-Altitude Periodic Breathing in Nonacclimatized Healthy Individuals.

Central sleep apnea (CSA) is common at high altitude, leading to desaturation and sleep disruption. We hypothesized that noninvasive ventilation using adaptive servoventilation (ASV) would be effective at stabilizing CSA at altitude. Supplemental oxygen was evaluated for comparison. Healthy subjects were brought from sea level to 3800 m and underwent polysomnography on three consecutive nights. Subjects underwent each condition-No treatment, ASV, and supplemental oxygen-in random order. The primary outcome was the effect of ASV on oxygen desaturation index (ODI). Secondary outcomes included oxygen saturation, arousals, symptoms, and comparison to supplemental oxygen. Eighteen subjects underwent at least two treatment conditions. There was a significant difference in ODI across the three treatments. There was no statistical difference in ODI between no treatment and ASV (17.1 ± 4.2 vs. 10.7 ± 2.9 events/hour; p > 0.17) and no difference in saturation or arousal index. Compared with no treatment, oxygen improved the ODI (16.5 ± 4.5 events/hour vs. 0.5 ± 0.2 events/hour; p < 0.003), in addition to saturation and arousal index. We found that ASV was not clearly efficacious at controlling CSA in persons traveling to 3800 m, whereas supplemental oxygen resolved CSA. Adjustment in the ASV algorithm may improve efficacy. ASV may have utility in acclimatized persons or at more modest altitudes.

Sleep respiratory disturbances during the ascent to Mount Aconcagua.

IntroductionMountaineers exposed to hypobaric hypoxia (HH) show high-altitude periodic breathing (PB).ObjectiveTo analyze high-altitude PB during the ascent of Mount Aconcagua (Argentina).Materials and MethodsDescriptive study in healthy volunteers using respiratory polygraphy (RP) at different altitudes.ResultsWe studied 8 andinist, mean age: 36 years old (25-51), body mass index (BMI) of 23.6 (20.9-28.7) and 22.77 (20.9-27.7) upon return, p<0.01. RP without PB showed a lower Oxygen Desaturation Index (ODI) and a lower Apnea-Hypopnea-Index (AHI); 5.43 (0 - 20) versus 45.95 (2-122) p<0.001 and 3.9 (0-15.5) versus 44.35 (4-115) p<0.001. AHI increased with altitude at the expense of central apneas and hypopneas: p<0.05.ConclusionHigh-altitude PB is frequent above 2,581m.a.s.l. And it is characterized by short cycles. None of the mountaineers showed PB at baseline; however, high-altitude PB occurred in all subjects above 4,900 m.a.s.l

Clinical Practice Guideline on Management of Sleep Disorders in the Elderly.

Clinical Practice Guideline on Management of Sleep Disorders in the Elderly.

Time-varying signal analysis to detect high-altitude periodic breathing in climbers ascending to extreme altitude.

This work investigates the performance of cardiorespiratory analysis detecting periodic breathing (PB) in chest wall recordings in mountaineers climbing to extreme altitude. The breathing patterns of 34 mountaineers were monitored unobtrusively by inductance plethysmography, ECG and pulse oximetry using a portable recorder during climbs at altitudes between 4497 and 7546 m on Mt. Muztagh Ata. The minute ventilation (VE) and heart rate (HR) signals were studied, to identify visually scored PB, applying time-varying spectral, coherence and entropy analysis. In 411 climbing periods, 30-120 min in duration, high values of mean power (MP(VE)) and slope (MSlope(VE)) of the modulation frequency band of VE, accurately identified PB, with an area under the ROC curve of 88 and 89%, respectively. Prolonged stay at altitude was associated with an increase in PB. During PB episodes, higher peak power of ventilatory (MP(VE)) and cardiac (MP(LF)(HR) ) oscillations and cardiorespiratory coherence (MP(LF)(Coher)), but reduced ventilation entropy (SampEn(VE)), was observed. Therefore, the characterization of cardiorespiratory dynamics by the analysis of VE and HR signals accurately identifies PB and effects of altitude acclimatization, providing promising tools for investigating physiologic effects of environmental exposures and diseases.

Acetazolamide effect on high altitude periodic breathing during sleep. The HIGHCARE Alps project

Purpose: Periodic breathing (PB) is frequently reported at night at high altitude. We have previously shown that this respiratory pattern is less frequent in female subjects. Little is known about gender differences on the acetazolamide effect on this phenomenon. Aim of our randomized, double blind study was to explore whether acetazolamide may influence PB during sleep in males and females subjects under acute exposure to high altitude hypoxia. Methods: All subjects (43 healthy subjects, 22 male) participating in the HIGH altitude Cardiovascular Research Alps project were randomized to acetazolamide (250 mg x2/die) (ACZ) or placebo (PL). During the expedition we performed nocturnal cardiorespiratory polysomnography during the second night at Capanna Margherita Hut 4554 m above SL). Results: During night at 4554 m apnea-hypopnea index (AHI) was 40.87+ 27.83 events/h in male PL, 3.77+ 3.8 events/h in male ACZ, 7.33+3.99 events/h in female PL and 2.92+ 3.52 events/h in female ACZ. The mean SaO2 during the night is significantly higher both in males than in females with ACZ as compared with PL groups (p<0.001). Additionally min SaO2 is significantly higher in females ACZ vs females and males PL; conversely min SaO2 is significantly higher in males ACZ vs females PL (p<0.05), but no statistically significant difference is observed between min SaO2 in males ACZ and males PL (see Table). View this table: Conclusions: We previously showed that at high altitude PB at night affects more frequently males than females. The present data confirm AHI differences between males and females. Moreover the present study suggests that ACZ significantly reduces AHI in males increasing also the mean SaO2 during the night, but not the min SaO2. In females subjects ACZ reduces AHI without statistically significance, but increases significantly both the mean and min SaO2.In conclusion, our data suggest that the determinants of periodic breathing at high altitude are complex and not only linked to hypoxia, but also to the CO2 level and in particular to the gender related central and peripheral chemosensitivity.

Therapy for Sleep Hypoventilation and Central Apnea Syndromes

• Primary Central Sleep Apnea (CSA): We would recommend a trial of Positive Airway Pressure (PAP), acetazolamide, or zolpidem based on thorough consideration of risks and benefits and incorporation of patient preferences.• Central Sleep Apnea Due to Cheyne-Stokes Breathing Pattern in Congestive Heart Failure (CSR-CHF): We would recommend PAP devices such as continuous positive airway pressure (CPAP) or adaptive servo-ventilation (ASV) to normalize sleep-disordered breathing after optimizing treatment of heart failure. Oxygen may also be an effective therapy. Acetazolamide and theophylline may be considered if PAP or oxygen is not effective.• Central Sleep Apnea due to High-Altitude Periodic Breathing: We would recommend descent from altitude or supplemental oxygen. Acetazolamide may be used when descent or oxygen are not feasible, or in preparation for ascent to high altitude. Slow ascent may be preventative.• Central Sleep Apnea due to Drug or Substance: If discontinuation or reduction of opiate dose is not feasible or effective, we would recommend a trial of CPAP, and if not successful, treatment with ASV. If ASV is ineffective or if nocturnal hypercapnia develops, bilevel positive airway pressure-spontaneous timed mode (BPAP-ST) is recommended.• Obesity hypoventilation syndrome: We would recommend an initial CPAP trial. If hypoxia or hypercapnia persists on CPAP, BPAP, BPAP-ST or average volume assured pressure support (AVAPS™) is recommended. Tracheostomy with nocturnal ventilation should be considered when the above measures are not effective. Weight loss may be curative.• Neuromuscular or chest wall disease: We would recommend early implementation of BPAP-ST based on thorough consideration of risks and benefits and patient preferences. AVAPS™ may also be considered. We recommend close follow up due to disease progression.