1
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Rojas-Córdova S, Torres-Fraga MG, Rodríguez-Reyes YG, Guerrero-Zúñiga S, Vázquez-García JC, Carrillo-Alduenda JL. Altitude and Breathing during Sleep in Healthy Persons and Sleep Disordered Patients: A Systematic Review. Sleep Sci 2023; 16:117-126. [PMID: 37151770 PMCID: PMC10157825 DOI: 10.1055/s-0043-1767745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 06/28/2022] [Indexed: 05/09/2023] Open
Abstract
Objetive The aim of this systematic review is to analyze the recent scientific evidence of the clinical effects of altitude on breathing during sleep in healthy persons and sleep disordered patients. Material and Methods A search was carried out in PubMed and Scopus looking for articles published between January 1, 2010 and December 31, 2021, in English and Spanish, with the following search terms: "sleep disorders breathing and altitude". Investigations in adults and carried out at an altitude of 2000 meters above mean sea level (MAMSL) or higher were included. The correlation between altitude, apnea hypopnea index (AHI) and mean SpO2 during sleep was calculated. Results 18 articles of the 112 identified were included. A good correlation was found between altitude and AHI (Rs = 0.66 P = 0.001), at the expense of an increase in the central apnea index. Altitude is inversely proportional to oxygenation during sleep (Rs = -0.93 P = 0.001), and an increase in the desaturation index was observed (3% and 4%). On the treatment of respiratory disorders of sleeping at altitude, oxygen is better than servoventilation to correct oxygenation during sleep in healthy subjects and acetazolamide controlled respiratory events and oxygenation during sleep in patients with obstructive sleep apnea under treatment with CPAP. Conclusions Altitude increases AHI and decreases oxygenation during sleep; oxygen and acetazolamide could be an effective treatment for sleep-disordered breathing at altitude above 2000 MAMSL.
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Affiliation(s)
| | | | | | - Selene Guerrero-Zúñiga
- National Institute of Respiratory Diseases, Sleep Medicine Unit, Mexico City, Mexico City, Mexico
| | | | - José Luis Carrillo-Alduenda
- National Institute of Respiratory Diseases, Sleep Medicine Unit, Mexico City, Mexico City, Mexico
- Address for correspondence José Luis Carrillo-Alduenda
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2
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Abstract
Despite extensive research, there is currently no approved drug for obstructive sleep apnea (OSA) treatment. OSA is a heterogeneous condition that involves multiple dominating pathophysiological traits. Drug development in this field needs to address both pathophysiological mechanisms and associated comorbid conditions in order to meet requirements for long-term therapy in OSA. Several drug candidates have been proposed and ongoing phase II trials that target various forms of sleep-disordered breathing have been initiated. The field is moving toward tailored therapeutic approaches in patients with OSA.
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3
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Drago S, Campodónico J, Sandoval M, Berendsen R, Buijze GA. Voluntary Increase of Minute Ventilation for Prevention of Acute Mountain Sickness. Int J Sports Med 2022; 43:971-977. [PMID: 35760082 DOI: 10.1055/a-1832-0279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
This study evaluated the feasibility and efficacy of voluntary sustained hyperventilation during rapid ascent to high altitude for the prevention of acute mountain sickness (AMS). Study subjects (n=32) were volunteer participants in a 2-day expedition to Mount Leoneras (4954 m), starting at 2800m (base camp at 4120 m). Subjects were randomized to either: 1) an intervention group using the voluntary hyperventilation (VH) technique targeting an end-tidal CO2 (ETCO2)<20 mmHg; or 2) a group using acetazolamide (AZ). During the expedition, respiratory rate (28±20 vs. 18±5 breaths/min, mean±SD, P<0.01) and SpO2 (95%±4% vs. 89%±5%, mean±SD, P<0.01) were higher, and ETCO2 (17±4 vs. 26±4 mmHg, mean±SD, P<0.01) was lower in the VH group compared to the AZ group - as repeatedly measured at equal fixed intervals during the ascent - showing the feasibility of the VH technique. Regarding efficacy, the incidence of 6 (40%) subjects registering an LLS score≥3 in the VH group was non-inferior to the 3 (18%) subjects in the acetazolamide group (P=0.16, power 28%). Voluntary increase in minute ventilation is a feasible technique, but - despite the underpowered non-inferiority in this small-scale proof-of-concept trial - it is not likely to be as effective as acetazolamide to prevent AMS.
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Affiliation(s)
- Sebastian Drago
- Orthopedic Surgery, Hospital del Trabajador, Santiago, Chile.,Faculty of Medicine, Universidad de Los Andes, Santiago, Chile
| | - Juan Campodónico
- Faculty of Medicine, Universidad de Los Andes, Santiago, Chile.,Grupo de rescate médico en montaña (GREMM), Santiago, Chile
| | - Mario Sandoval
- Sport Medicine Department; Clínica MEDS, Santiago, Chile
| | - Remco Berendsen
- Anesthesia, Leiden University Medical Center, Leiden, Netherlands
| | - Geert Alexander Buijze
- Orthopaedic Surgery and Sports Medicine, Clinique Générale, Annecy, France.,Orthopaedic Surgery, Lapeyronie Hospital, Montpellier University Medical Center, Montpellier, France.,Orthopaedic Surgery, Amsterdam University Medical Center, Amsterdam, Netherlands
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4
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Hedner J, Stenlöf K, Zou D, Hoff E, Hansen C, Kuhn K, Lennartz P, Grote L. A Randomized Controlled Trial Exploring Safety and Tolerability of Sulthiame in Sleep Apnea. Am J Respir Crit Care Med 2022; 205:1461-1469. [PMID: 35202553 DOI: 10.1164/rccm.202109-2043oc] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONAL Current therapies in obstructive sleep apnea (OSA) are limited by insufficient efficacy, compliance or tolerability. An effective pharmacological treatment in OSA is warranted. Carbonic anhydrase (CA) inhibition has been shown to ameliorate OSA. OBJECTIVE To explore safety and tolerability of the CA inhibitor sulthiame (STM) in OSA. METHODS A four week double-blind, randomized, placebo-controlled dose guiding trial in patients with moderate/severe OSA not tolerating positive airway pressure treatment. MEASUREMENTS AND RESULTS Intermittent paresthesia was reported by 79, 67 and 18% of patients receiving 400 mg STM (N=34), 200 mg STM (N=12) or placebo (N=22), respectively. Dyspnea was reported only after 400 mg STM (18%). Six patients in the higher dose group withdrew due to an adverse event. There were no serious adverse events. STM reduced the apnea-hypopnea index (AHI) from 55.3 to 33.1 events/h ( 41.0%) in the 400 mg group and from 61.2 to 40.7 events/h ( 32.1%) after 200 mg (p<0.001, respectively). Corresponding placebo values were 53.9 and 50.9 events/h ( 5.4 %). The AHI reduction threshold of ≥50% was reached in 40% after 400 mg, 25% after 200 mg and 5% following placebo. Mean overnight oxygen saturation improved by 1.1% after 400 mg and 200 mg (p<0.001 and p=0.034, respectively). Patient related outcomes were unchanged. CONCLUSIONS STM showed a satisfactory safety profile in moderate/severe OSA. STM reduced OSA by more than 20 events/h, one of the strongest reductions reported in a drug trial in OSA. Larger scale clinical studies of STM in OSA are justified. Clinical trial registration available at https://www.clinicaltrialsregister.eu/https://www.clinicaltrialsregister.eu/, ID: 2017-004767-13.
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Affiliation(s)
- Jan Hedner
- University of Gothenburg Sahlgrenska Academy, 70712, Internal Medicine, Center for Sleep and Wake Disorders, Goteborg, Sweden;
| | - Kaj Stenlöf
- University of Gothenburg Sahlgrenska Academy, 70712, Internal Medicine, Center for Sleep and Wake Disorders, Goteborg, Sweden
| | - Ding Zou
- University of Gothenburg Sahlgrenska Academy, 70712, Internal Medicine, Center for Sleep and Wake Disorders, Goteborg, Sweden
| | - Erik Hoff
- University of Gothenburg Sahlgrenska Academy, 70712, Internal Medicine, Center for Sleep and Wake Disorders, Goteborg, Sweden
| | | | - Katrin Kuhn
- Desitin Arzneimittel GmbH, 60840, Hamburg, Germany
| | | | - Ludger Grote
- University of Gothenburg Sahlgrenska Academy, 70712, Internal Medicine, Center for Sleep and Wake Disorders, Goteborg, Sweden.,Sahlgrenska University Hospital, 56749, Sleep Laboratory, Pulmonary Medicine, Goteborg, Sweden
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5
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Ni YN, Yang H, Thomas RJ. The role of acetazolamide in sleep apnea at sea level: a systematic review and meta-analysis. J Clin Sleep Med 2021; 17:1295-1304. [PMID: 33538687 DOI: 10.5664/jcsm.9116] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
STUDY OBJECTIVES The recognition of specific endotypes as drivers of sleep apnea suggests the need of therapies targeting individual mechanisms. Acetazolamide is known to stabilize respiration at high altitude but benefits at sea level are less well understood. METHODS All controlled studies of acetazolamide in obstructive sleep apnea and/or central sleep apnea (CSA) were evaluated. The primary outcome was the apnea-hypopnea index. RESULTS Fifteen trials with a total of 256 patients were pooled in our systematic review. Acetazolamide reduced the overall apnea-hypopnea index (mean difference [MD] -15.82, 95% CI: -21.91 to -9.74, P < .00001) in central sleep apnea (MD -22.60, 95% CI: -29.11 to -16.09, P < .00001), but not in obstructive sleep apnea (MD -10.29, 95% CI: -33.34 to 12.77, P = .38). Acetazolamide reduced the respiratory related arousal index (MD -0.82, 95% CI: -1.56 to -0.08, P = .03), improved partial arterial of oxygen (MD 11.62, 95% CI: 9.13-14.11, P < .00001), mean oxygen saturation (MD 1.78, 95% CI: 0.53-3.04, P = .005), total sleep time (MD 25.74, 95% CI: 4.10-47.38, P = .02), N2 sleep (MD 3.34, 95% CI: 0.12-6.56, P = .04) and sleep efficiency (MD 4.83, 95% CI: 0.53-9.13, P = .03). CONCLUSIONS Acetazolamide improves the apnea-hypopnea index and several sleep metrics in central sleep apnea. The drug may be of clinical benefit in patients with high loop gain apnea of various etiologies and patterns. The existence of high heterogeneity is an important limitation in applicability of our analysis. SYSTEMATIC REVIEW REGISTRATION Registry: PROSPERO; Name: The effect of acetazolamide in patients with sleep apnea at sea level: a systematic review and meta analysis; URL: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020163316; Identifier: CRD42020163316.
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Affiliation(s)
- Yue-Nan Ni
- Division of Pulmonary, Critical Care and Sleep Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts.,Department of Respiratory and Critical Care Medicine, West China School of Medicine and West China Hospital, Sichuan University, China
| | - Huan Yang
- Department of Respiratory and Critical Care Medicine, West China School of Medicine and West China Hospital, Sichuan University, China
| | - Robert Joseph Thomas
- Division of Pulmonary, Critical Care and Sleep Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
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6
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Venkat D, Dhillon K, Rowley JA. Effects of High Altitude on Sleep and Respiratory System. CURRENT PULMONOLOGY REPORTS 2021. [DOI: 10.1007/s13665-021-00276-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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7
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Winkler D, Katz I, Warden A, Thornton A, Farjot G. Identifying medically relevant xenon protein targets by in silico screening of the structural proteome. Med Gas Res 2021; 13:33-38. [PMID: 35946221 PMCID: PMC9480358 DOI: 10.4103/2045-9912.333858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In a previous study, in silico screening of the binding of almost all proteins in the Protein Data Bank to each of the five noble gases xenon, krypton, argon, neon, and helium was reported. This massive and rich data set requires analysis to identify the gas-protein interactions that have the best binding strengths, those where the binding of the noble gas occurs at a site that can modulate the function of the protein, and where this modulation might generate clinically relevant effects. Here, we report a preliminary analysis of this data set using a rational, heuristic score based on binding strength and location. We report a partial prioritized list of xenon protein targets and describe how these data can be analyzed, using arginase and carbonic anhydrase as examples. Our aim is to make the scientific community aware of this massive, rich data set and how it can be analyzed to accelerate future discoveries of xenon-induced biological activity and, ultimately, the development of new “atomic” drugs.
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8
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Shlim DR. The use of acetazolamide for the prevention of high-altitude illness. J Travel Med 2020; 27:5693888. [PMID: 31897486 DOI: 10.1093/jtm/taz106] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 12/05/2019] [Accepted: 12/19/2019] [Indexed: 12/27/2022]
Abstract
BACKGROUND Modern travel means that many travellers can arrive abruptly to high-altitude destinations without doing any trekking or climbing. Airports in high-altitude cities mean that travellers can go from sea level to over 3350-3960 m (11 000-13 000 feet) in a matter of hours, putting themselves at risk for high-altitude illness (HAI). METHODS Acetazolamide has been shown to be an effective way to help prevent HAI on such itineraries. The risk of HAI on rapid arrival to altitudes over 3350 m (11 000 feet) has been shown to range from 35% to nearly 50%. The risk can be higher for high-altitude trekking. This risk is far higher than most travel medicine risks and is on a par with the risk of travellers' diarrhea in high risk destinations. RESULT The use of prophylactic acetazolamide in a dosage of 125 mg every 12 h is highly effective at diminishing the risk of HAI. CONCLUSION Travel medicine practitioners should become comfortable with assessing the risk of HAI and determining when it is appropriate to offer acetazolamide prophylaxis to prevent HAI.
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Affiliation(s)
- David R Shlim
- Jackson Hole Travel and Tropical Medicine, Jackson Hole, WY, USA
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9
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Mishra CB, Tiwari M, Supuran CT. Progress in the development of human carbonic anhydrase inhibitors and their pharmacological applications: Where are we today? Med Res Rev 2020; 40:2485-2565. [PMID: 32691504 DOI: 10.1002/med.21713] [Citation(s) in RCA: 134] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 06/14/2020] [Accepted: 07/03/2020] [Indexed: 12/21/2022]
Abstract
Carbonic anhydrases (CAs, EC 4.2.1.1) are widely distributed metalloenzymes in both prokaryotes and eukaryotes. They efficiently catalyze the reversible hydration of carbon dioxide to bicarbonate and H+ ions and play a crucial role in regulating many physiological processes. CAs are well-studied drug target for various disorders such as glaucoma, epilepsy, sleep apnea, and high altitude sickness. In the past decades, a large category of diverse families of CA inhibitors (CAIs) have been developed and many of them showed effective inhibition toward specific isoforms, and effectiveness in pathological conditions in preclinical and clinical settings. The discovery of isoform-selective CAIs in the last decade led to diminished side effects associated with off-target isoforms inhibition. The many new classes of such compounds will be discussed in the review, together with strategies for their development. Pharmacological advances of the newly emerged CAIs in diseases not usually associated with CA inhibition (neuropathic pain, arthritis, cerebral ischemia, and cancer) will also be discussed.
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Affiliation(s)
- Chandra B Mishra
- Department of Bioorganic Chemistry, Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India.,Department of Pharmaceutical Chemistry, College of Pharmacy, Sookmyung Women's University, Seoul, South Korea
| | - Manisha Tiwari
- Department of Bioorganic Chemistry, Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | - Claudiu T Supuran
- Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Florence, Italy
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10
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Hannah SS, McFadden S, McNeilly A, McClean C. "Take My Bone Away?" Hypoxia and bone: A narrative review. J Cell Physiol 2020; 236:721-740. [PMID: 32643217 DOI: 10.1002/jcp.29921] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 12/11/2022]
Abstract
To maintain normal cellular and physiological function, sufficient oxygen is required. Recently, evidence has suggested that hypoxia, either pathological or environmental, may influence bone health. It appears that bone cells are distinctly responsive to hypoxic stimuli; for better or worse, this is still yet to be elucidated. Hypoxia has been shown to offer potentially therapeutic effects for bone by inducing an osteogenic-angiogenic response, although, others have noted excessive osteoclastic bone resorption instead. Much evidence suggests that the hypoxic-inducible pathway is integral in mediating the changes in bone metabolism. Furthermore, many factors associated with hypoxia including changes in energy metabolism, acid-base balance and the increased generation of reactive oxygen species, are known to influence bone metabolism. This review aims to examine some of the putative mechanisms responsible for hypoxic-induced alterations of bone metabolism, with regard to osteoclasts and osteoblasts, both positive and negative.
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Affiliation(s)
- Scott S Hannah
- Sport and Exercise Sciences Research Institute, Ulster University, Newtownabbey, Antrim, UK
| | - Sonyia McFadden
- Institute of Nursing and Health Research, Ulster University, Newtownabbey, Antrim, UK
| | - Andrea McNeilly
- Sport and Exercise Sciences Research Institute, Ulster University, Newtownabbey, Antrim, UK
| | - Conor McClean
- Sport and Exercise Sciences Research Institute, Ulster University, Newtownabbey, Antrim, UK
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11
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Zollino M, Zweier C, Van Balkom ID, Sweetser DA, Alaimo J, Bijlsma EK, Cody J, Elsea SH, Giurgea I, Macchiaiolo M, Smigiel R, Thibert RL, Benoist I, Clayton-Smith J, De Winter CF, Deckers S, Gandhi A, Huisman S, Kempink D, Kruisinga F, Lamacchia V, Marangi G, Menke L, Mulder P, Nordgren A, Renieri A, Routledge S, Saunders CJ, Stembalska A, Van Balkom H, Whalen S, Hennekam RC. Diagnosis and management in Pitt-Hopkins syndrome: First international consensus statement. Clin Genet 2019; 95:462-478. [PMID: 30677142 DOI: 10.1111/cge.13506] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 12/20/2018] [Accepted: 01/09/2019] [Indexed: 02/06/2023]
Abstract
Pitt-Hopkins syndrome (PTHS) is a neurodevelopmental disorder characterized by intellectual disability, specific facial features, and marked autonomic nervous system dysfunction, especially with disturbances of regulating respiration and intestinal mobility. It is caused by variants in the transcription factor TCF4. Heterogeneity in the clinical and molecular diagnostic criteria and care practices has prompted a group of international experts to establish guidelines for diagnostics and care. For issues, for which there was limited information available in international literature, we collaborated with national support groups and the participants of a syndrome specific international conference to obtain further information. Here, we discuss the resultant consensus, including the clinical definition of PTHS and a molecular diagnostic pathway. Recommendations for managing particular health problems such as dysregulated respiration are provided. We emphasize the need for integration of care for physical and behavioral issues. The recommendations as presented here will need to be evaluated for improvements to allow for continued optimization of diagnostics and care.
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Affiliation(s)
- Marcella Zollino
- Fondazione Policlinico Universitario A.Gemelli, IRCCS, UOC Genetica.,Università Cattolica Sacro Cuore, Istituto di Medicina Genomica, Roma, Italy
| | - Christiane Zweier
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Ingrid D Van Balkom
- Jonx Department of (Youth) Mental Health and Autism, Lentis Psychiatric Institute, Groningen, The Netherlands.,Rob Giel Research Centre, Department of Psychiatry, University Medical Center Groningen, Groningen, The Netherlands
| | - David A Sweetser
- Division of Medical Genetics and Metabolism, Massachusetts General Hospital for Children, Boston, Massachusetts
| | - Joseph Alaimo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Emilia K Bijlsma
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Jannine Cody
- Department of Pediatrics, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Sarah H Elsea
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Irina Giurgea
- Sorbonne Université, INSERM, UMR_S 933, Assistance Publique Hôpitaux de Paris, Département de Génétique Médicale, Hôpital Trousseau, Paris, France
| | - Marina Macchiaiolo
- Rare and Genetic Diseases Unit, Bambino Gesù Children's Hospital, Rome, Italy
| | - Robert Smigiel
- Department of Pediatrics, Division of Pediatrics and Rare Disorders, Wroclaw Medical University, Wroclaw, Poland
| | - Ronald L Thibert
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Ingrid Benoist
- Dutch Pitt-Hopkins Syndrome Foundation, Vlaggeschip, Oosterhout, The Netherlands
| | - Jill Clayton-Smith
- Manchester Centre for Genomic Medicine, St Mary's Hospital, and Division of Evolution and Genomic Sciences School of Biological Sciences, University of Manchester, Manchester, UK
| | - Channa F De Winter
- Organisation for Individuals with Intellectual Disabilities, Trajectum, Zwolle, The Netherlands
| | - Stijn Deckers
- Department of Pedagogical Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Anusha Gandhi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Sylvia Huisman
- Department of Pediatrics, Academic Medical Centre, Amsterdam UMC, Amsterdam, The Netherlands
| | - Dagmar Kempink
- Department of Orthopedic Surgery, Sophia Children's Hospital, UMCR, Rotterdam, The Netherlands
| | - Frea Kruisinga
- Department of Pediatrics, Academic Medical Centre, Amsterdam UMC, Amsterdam, The Netherlands
| | | | - Giuseppe Marangi
- Fondazione Policlinico Universitario A.Gemelli, IRCCS, UOC Genetica.,Università Cattolica Sacro Cuore, Istituto di Medicina Genomica, Roma, Italy
| | - Leonie Menke
- Department of Pediatrics, Academic Medical Centre, Amsterdam UMC, Amsterdam, The Netherlands
| | - Paul Mulder
- Jonx Department of (Youth) Mental Health and Autism, Lentis Psychiatric Institute, Groningen, The Netherlands.,Rob Giel Research Centre, Department of Psychiatry, University Medical Center Groningen, Groningen, The Netherlands
| | - Ann Nordgren
- Karolinska Center for Rare Diseases, Karolinska University Hospital, Stockholm, Sweden
| | | | | | - Carol J Saunders
- Center for Pediatric Genomic Medicine, Children's Mercy Hospital, Kansas City, Missouri
| | | | - Hans Van Balkom
- Behavioral Science Institute, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Sandra Whalen
- Sorbonne Université, INSERM, UMR_S 933, Assistance Publique Hôpitaux de Paris, Département de Génétique Médicale, Hôpital Trousseau, Paris, France
| | - Raoul C Hennekam
- Department of Pediatrics, Academic Medical Centre, Amsterdam UMC, Amsterdam, The Netherlands
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12
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Hung PH, Lin FC, Tsai HC, Chao HS, Chou CW, Chang SC. The usefulness of prophylactic use of acetazolamide in subjects with acute mountain sickness. J Chin Med Assoc 2019; 82:126-132. [PMID: 30839503 DOI: 10.1097/jcma.0000000000000014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND The mechanisms of acetazolamide (ACZ) in the prophylaxis of acute mountain sickness (AMS) remain unclear. This study evaluated the changes in physiological variables of sleep and heart rate variability (HRV) in subjects with earlier history of AMS who underwent prophylactic treatment of ACZ. METHODS Nonacclimatized healthy subjects were transported using a bus from 555 m to 3150 m within 3 hours. Polysomnography (PSG) was performed 3 days before ascent (T0), for two consecutive nights at 3150 m (T1 and T2), and 2 days after descent (T3). HRV was measured before sleep and after awakening from T0 to T3. AMS was diagnosed using a self-reported Lake Louise score questionnaire. Subjects found confirmed to have AMS were enrolled in this study. The physiological variables and HRV were compared in AMS subjects without (control group) and with prophylactic ACZ (prophylactic ACZ group). RESULTS Thirteen AMS subjects were enrolled. The PSG results were analyzed in eight and HRV were analyzed in nine of the 13 subjects. The prophylactic use of ACZ in the subjects with a history of AMS significantly improved sleep efficiency (p = 0.012) and awakening percentages (p = 0.017) at T1, significantly higher levels of arterial oxygen saturation (SaO2) and lower values of partial pressure end-tidal carbon dioxide tension (PETCO2) at four time points. Furthermore, they had a higher rapid eye movement sleep percentage (p = 0.05) at T2. Prophylactic ACZ treatment significantly increased the normalized unit of high frequency at T1 after awakening (p = 0.028). CONCLUSION Significantly higher quality of sleep, higher SaO2 during sleep, and lower PETCO2 at high altitude were found in the subjects with a history of AMS using prophylactic ACZ before rapid ascent. ACZ may accelerate the acclimatization process for rapid ascents to high altitudes by increasing parasympathetic tone based on HRV analyses.
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Affiliation(s)
- Pin-Hsi Hung
- Institute of Emergency and Critical Care Medicine, National Yang-Ming University, Taipei, Taiwan, ROC
- Department of Ear-Nose-Throat, Taipei City Hospital, Yangming Branch, Taipei, Taiwan, ROC
| | - Fang-Chi Lin
- Department of Chest Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Department of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Han-Chen Tsai
- Department of Nursing, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Heng-Sheng Chao
- Department of Chest Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Department of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Chung-Wei Chou
- Department of Chest Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Department of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Shi-Chuan Chang
- Institute of Emergency and Critical Care Medicine, National Yang-Ming University, Taipei, Taiwan, ROC
- Department of Chest Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
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13
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Joyce K, Lucas S, Imray C, Balanos G, Wright AD. Advances in the available non-biological pharmacotherapy prevention and treatment of acute mountain sickness and high altitude cerebral and pulmonary oedema. Expert Opin Pharmacother 2018; 19:1891-1902. [DOI: 10.1080/14656566.2018.1528228] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- K.E. Joyce
- School of Sport, Exercise, & Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - S.J.E. Lucas
- School of Sport, Exercise, & Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - C.H.E. Imray
- Department of Vascular Surgery, University Hospitals of Coventry and Warwickshire; Warwick Medical School, Coventry, UK
| | - G.M Balanos
- School of Sport, Exercise, & Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - A. D. Wright
- Department of Medicine, University of Birmingham, Edgbaston, UK
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14
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Moraga FA, Osorio J, Calderón-Jofré R, Pedreros A. Hemoconcentration During Maximum Exercise in Miners with Chronic Intermittent Exposure to Hypobaric Hypoxia (3800 m). High Alt Med Biol 2017; 19:15-20. [PMID: 29035586 DOI: 10.1089/ham.2017.0011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Moraga, Fernando A., Jorge Osorio, Rodrigo Calderón-Jofré, and Andrés Pedreros. Hemoconcentration during maximum exercise in miners with chronic intermittent exposure to hypobaric hypoxia (3800 m). High Alt Med Biol. 19:15-20, 2018. OBJECTIVE To evaluate the effect of maximum exercise on hemoconcentration in miners with chronic intermittent hypobaric hypoxia (CIHH) at 3800 m. MATERIALS AND METHODS Sixteen miners with CIHH at high altitude (3800 m) were subjected to maximum exercise levels on a cycle ergometer, increasing exercise load by 50 W every 3 minutes at sea level and high altitude (3800 m). During exercise, arterial oxygen saturation and heart rate were measured. Blood samples were taken at each step to measure hemoglobin concentration and hematocrit. Arterial blood oxygen content was also calculated. RESULTS At sea level, a decrease in arterial oxygen saturation to 92.1% ± 2.5% was observed at 150 W and the hematocrit, hemoglobin concentration and oxygen content were not altered. At high altitude, arterial oxygen saturation decreased, reaching 88.2% ± 4.9% at 50 W and remained constant during the entire exercise protocol. Hemoglobin concentration and hematocrit increased reaching 16.4 ± 0.9 g/dL and 48.8% ± 1.6%, respectively, at 100 W and were maintained until recovery. Arterial oxygen content was constant during exercise and increased in the recovery period. CONCLUSION An increase in hemoglobin concentration during exercise compensates for the decline in arterial oxygen saturation, meanwhile arterial oxygen content remains constant.
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Affiliation(s)
- Fernando A Moraga
- 1 Laboratorio de Fisiología, Hipoxia y Función Vascular, Departamento de Ciencias Biomédicas, Facultad de Medicina, Universidad Católica del Norte , Coquimbo, Chile
| | - Jorge Osorio
- 2 Instituto de Estudios de la Salud , Universidad Arturo Prat, Iquique, Chile
| | - Rodrigo Calderón-Jofré
- 1 Laboratorio de Fisiología, Hipoxia y Función Vascular, Departamento de Ciencias Biomédicas, Facultad de Medicina, Universidad Católica del Norte , Coquimbo, Chile
| | - Andrés Pedreros
- 1 Laboratorio de Fisiología, Hipoxia y Función Vascular, Departamento de Ciencias Biomédicas, Facultad de Medicina, Universidad Católica del Norte , Coquimbo, Chile
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Abstract
Purpose of Review Pitt Hopkins syndrome (PTHS) is a rare neurodevelopmental disorder that results from mutations of the clinically pleiotropic Transcription Factor 4 (TCF4) gene. Mutations in the genomic locus of TCF4 on chromosome 18 have been linked to multiple disorders including 18q syndrome, schizophrenia, Fuch's corneal dystrophy, and sclerosing cholangitis. For PTHS, TCF4 mutation or deletion leads to the production of a dominant negative TCF4 protein and/or haploinsufficiency that results in abnormal brain development. The biology of TCF4 has been studied for several years in regards to its role in immune cell differentiation, although its role in neurodevelopment and the mechanisms resulting in the severe symptoms of PTHS are not well studied. Recent Findings Here, we summarize the current understanding of PTHS and recent findings that have begun to describe the biological implications of TCF4 deficiency during brain development and into adulthood. In particular, we focus on recent work that has looked at the role of TCF4 biology within the context of PTHS and highlight the potential for identification of therapeutic targets for PTHS. Summary PTHS research continues to uncover mutations in TCF4 that underlie the genetic cause of this rare disease, and emerging evidence for molecular mechanisms that TCF4 regulates in brain development and neuronal function is contributing to a more complete picture of how pathology arises from this genetic basis, with important implications for the potential of future clinical care.
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Jullian-Desayes I, Revol B, Chareyre E, Camus P, Villier C, Borel JC, Pepin JL, Joyeux-Faure M. Impact of concomitant medications on obstructive sleep apnoea. Br J Clin Pharmacol 2016; 83:688-708. [PMID: 27735059 DOI: 10.1111/bcp.13153] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 10/07/2016] [Accepted: 10/10/2016] [Indexed: 01/11/2023] Open
Abstract
Obstructive sleep apnoea (OSA) is characterized by repeated episodes of apnoea and hypopnoea during sleep. Little is known about the potential impact of therapy drugs on the underlying respiratory disorder. Any influence should be taken into account and appropriate action taken, including drug withdrawal if necessary. Here, we review drugs in terms of their possible impact on OSA; drugs which (1) may worsen OSA; (2) are unlikely to have an impact on OSA; (3) those for which data are scarce or contradictory; and (4) drugs with a potentially improving effect. The level of evidence is ranked according to three grades: A - randomized controlled trials (RCTs) with high statistical power; B - RCTs with lower power, non-randomized comparative studies and observational studies; C - retrospective studies and case reports. Our review enabled us to propose clinical recommendations. Briefly, agents worsening OSA or inducing weight gain, that must be avoided, are clearly identified. Drugs such as 'Z drugs' and sodium oxybate should be used with caution as the literature contains conflicting results. Finally, larger trials are needed to clarify the potential positive impact of certain drugs on OSA. In the meantime, some, such as diuretics or other antihypertensive medications, are helpful in reducing OSA-associated cardiovascular morbidity.
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Affiliation(s)
- Ingrid Jullian-Desayes
- HP2 Laboratory, Inserm U1042 Unit, University Grenoble Alps, Grenoble, France.,EFCR Laboratory, Thorax and Vessels, Grenoble Alps University Hospital, Grenoble, France
| | - Bruno Revol
- HP2 Laboratory, Inserm U1042 Unit, University Grenoble Alps, Grenoble, France.,EFCR Laboratory, Thorax and Vessels, Grenoble Alps University Hospital, Grenoble, France.,Pharmacovigilance Department, Grenoble Alps University Hospital, Grenoble, France
| | - Elisa Chareyre
- HP2 Laboratory, Inserm U1042 Unit, University Grenoble Alps, Grenoble, France.,EFCR Laboratory, Thorax and Vessels, Grenoble Alps University Hospital, Grenoble, France
| | - Philippe Camus
- Pneumology Department, Dijon Bourgogne University Hospital, Dijon, France
| | - Céline Villier
- Pharmacovigilance Department, Grenoble Alps University Hospital, Grenoble, France
| | - Jean-Christian Borel
- HP2 Laboratory, Inserm U1042 Unit, University Grenoble Alps, Grenoble, France.,EFCR Laboratory, Thorax and Vessels, Grenoble Alps University Hospital, Grenoble, France
| | - Jean-Louis Pepin
- HP2 Laboratory, Inserm U1042 Unit, University Grenoble Alps, Grenoble, France.,EFCR Laboratory, Thorax and Vessels, Grenoble Alps University Hospital, Grenoble, France
| | - Marie Joyeux-Faure
- HP2 Laboratory, Inserm U1042 Unit, University Grenoble Alps, Grenoble, France.,EFCR Laboratory, Thorax and Vessels, Grenoble Alps University Hospital, Grenoble, France
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Collier DJ, Wolff CB, Hedges A, Nathan J, Flower RJ, Milledge JS, Swenson ER. Benzolamide improves oxygenation and reduces acute mountain sickness during a high-altitude trek and has fewer side effects than acetazolamide at sea level. Pharmacol Res Perspect 2016; 4:e00203. [PMID: 27433337 PMCID: PMC4876137 DOI: 10.1002/prp2.203] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 10/22/2015] [Accepted: 11/06/2015] [Indexed: 01/05/2023] Open
Abstract
Acetazolamide is the standard carbonic anhydrase (CA) inhibitor used for acute mountain sickness (AMS), however some of its undesirable effects are related to intracellular penetrance into many tissues, including across the blood-brain barrier. Benzolamide is a much more hydrophilic inhibitor, which nonetheless retains a strong renal action to engender a metabolic acidosis and ventilatory stimulus that improves oxygenation at high altitude and reduces AMS. We tested the effectiveness of benzolamide versus placebo in a first field study of the drug as prophylaxis for AMS during an ascent to the Everest Base Camp (5340 m). In two other studies performed at sea level to test side effect differences between acetazolamide and benzolamide, we assessed physiological actions and psychomotor side effects of two doses of acetazolamide (250 and 1000 mg) in one group of healthy subjects and in another group compared acetazolamide (500 mg), benzolamide (200 mg) and lorazepam (2 mg) as an active comparator for central nervous system (CNS) effects. At high altitude, benzolamide-treated subjects maintained better arterial oxygenation at all altitudes (3-6% higher at all altitudes above 4200 m) than placebo-treated subjects and reduced AMS severity by roughly 50%. We found benzolamide had fewer side effects, some of which are symptoms of AMS, than any of the acetazolamide doses in Studies 1 and 2, but equal physiological effects on renal function. The psychomotor side effects of acetazolamide were dose dependent. We conclude that benzolamide is very effective for AMS prophylaxis. With its lesser CNS effects, benzolamide may be superior to acetazolamide, in part, because some of the side effects of acetazolamide may contribute to and be mistaken for AMS.
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Affiliation(s)
- David J. Collier
- Centres of Clinical Pharmacology and Biochemical PharmacologyWilliam Harvey Research InstituteBarts, Queen Mary University of LondonLondonEC1M 6BQUnited Kingdom
| | - Chris B. Wolff
- Centres of Clinical Pharmacology and Biochemical PharmacologyWilliam Harvey Research InstituteBarts, Queen Mary University of LondonLondonEC1M 6BQUnited Kingdom
| | - Anne‐Marie Hedges
- Centres of Clinical Pharmacology and Biochemical PharmacologyWilliam Harvey Research InstituteBarts, Queen Mary University of LondonLondonEC1M 6BQUnited Kingdom
| | - John Nathan
- The Health CentreSurreyRH8 OBQUnited Kingdom
| | - Rod J. Flower
- Centres of Clinical Pharmacology and Biochemical PharmacologyWilliam Harvey Research InstituteBarts, Queen Mary University of LondonLondonEC1M 6BQUnited Kingdom
| | - James S. Milledge
- Centre for Altitude Space and Extreme Environment Medicine UCLLondonN19 5LWUnited Kingdom
| | - Erik R. Swenson
- Medical ServiceVeterans Affairs Puget Sound Health Care SystemUniversity of WashingtonSeattleWashingtonUSA98108
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18
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Harrison MF, Anderson PJ, Johnson JB, Richert M, Miller AD, Johnson BD. Acute Mountain Sickness Symptom Severity at the South Pole: The Influence of Self-Selected Prophylaxis with Acetazolamide. PLoS One 2016; 11:e0148206. [PMID: 26848757 PMCID: PMC4744068 DOI: 10.1371/journal.pone.0148206] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 01/14/2016] [Indexed: 01/23/2023] Open
Abstract
Introduction Acetazolamide, a carbonic anhydrase inhibitor, remains the only FDA approved pharmaceutical prophylaxis for acute mountain sickness (AMS) though its effectiveness after rapid transport in real world conditions is less clear. Methods Over 2 years, 248 healthy adults traveled by airplane from sea level (SL) to the South Pole (ALT, ~3200m) and 226 participants provided Lake Louise Symptom Scores (LLSS) on a daily basis for 1 week; vital signs, blood samples, and urine samples were collected at SL and at ALT. Acetazolamide was available to any participant desiring prophylaxis. Comparisons were made between the acetazolamide with AMS (ACZ/AMS) (n = 42), acetazolamide without AMS (ACZ/No AMS)(n = 49), no acetazolamide with AMS (No ACZ/AMS) (n = 56), and the no acetazolamide without AMS (No ACZ/No AMS) (n = 79) groups. Statistical analysis included Chi-squared and one-way ANOVA with Bonferroni post-hoc tests. Significance was p≤0.05. Results No significant differences were found for between-group characteristics or incidence of AMS between ACZ and No ACZ groups. ACZ/AMS reported greater LLSS, BMI, and red cell distribution width. ACZ/No AMS had the highest oxygen saturation (O2Sat) at ALT. No significant differences were found in serum electrolyte concentrations or PFT results. Discussion Acetazolamide during rapid ascent provided no apparent protection from AMS based on LLSS. However, it is unclear if this lack of effect was directly associated with the drug or if perhaps there was some selection bias with individuals taking ACZ more likely to have symptoms or if there may have been more of perceptual phenomenon related to a constellation of side effects.
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Affiliation(s)
- Michael F. Harrison
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Emergency Medicine, Henry Ford Hospital, Detroit, Michigan, United States of America
| | - Paul J. Anderson
- Division of Preventive, Occupational, and Aerospace Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Jacob B. Johnson
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Maile Richert
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Andrew D. Miller
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Bruce D. Johnson
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
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19
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Central Sleep Apnea at High Altitude. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 903:275-83. [DOI: 10.1007/978-1-4899-7678-9_19] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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20
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Teppema LJ, Swenson ER. The noncarbonic anhydrase inhibiting acetazolamide analog N-methylacetazolamide reduces the hypercapnic, but not hypoxic, ventilatory response. Physiol Rep 2015; 3:3/8/e12484. [PMID: 26290531 PMCID: PMC4562570 DOI: 10.14814/phy2.12484] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Previous studies have shown that the carbonic anhydrase (CA) inhibitors acetazolamide (AZ) and methazolamide (MZ) have inhibiting actions on breathing. Classically these have been attributed to CA inhibition, but other effects unrelated to CA inhibition have been identified in other tissues. To explore this possibility in the control of ventilation by the central nervous system, we investigated whether an AZ-analog without CA inhibiting properties, by virtue of a single methylation on the sulfonamide moiety, N-methylacetazolamide (NMA), would still display similar actions to acetazolamide and methazolamide. NMA (20 mg kg−1) was given intravenously to anesthetized cats and we measured the responses to steady-state isocapnic hypoxia and stepwise changes in end-tidal pco2 before and after infusion of this AZ analog using the technique of end-tidal forcing. NMA caused a large decrease in the apneic threshold and CO2 sensitivity very similar to those previously observed with AZ and MZ, suggesting that these effects are mediated independently of CA inhibition. In contrast to acetazolamide, but similar to methazolamide, NMA did not affect the steady-state isocapnic hypoxic response. In conclusion, our data reveal complex effects of sulfonamides with very similar structure to AZ that reveal both CA-dependent and CA-independent effects, which need to be considered when using AZ as a probe for the role of CA in the control of ventilation.
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Affiliation(s)
- Luc J Teppema
- Department of Anesthesiology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Erik R Swenson
- Pulmonary and Critical Care Medicine, VA Puget Sound Health Care System, University of Washington, Seattle, Washington, USA
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21
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Hermand E, Lhuissier FJ, Larribaut J, Pichon A, Richalet JP. Ventilatory oscillations at exercise: effects of hyperoxia, hypercapnia, and acetazolamide. Physiol Rep 2015; 3:3/6/e12446. [PMID: 26109194 PMCID: PMC4510637 DOI: 10.14814/phy2.12446] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Periodic breathing has been found in patients with heart failure and sleep apneas, and in healthy subjects in hypoxia, during sleep and wakefulness, at rest and, recently, at exercise. To unravel the cardiorespiratory parameters liable to modulate the amplitude and period of ventilatory oscillations, 26 healthy subjects were tested under physiological (exercise) and environmental (hypoxia, hyperoxia, hyperoxic hypercapnia) stresses, and under acetazolamide (ACZ) treatment. A fast Fourier transform spectral analysis of breath-by-breath ventilation evidenced an increase in peak power under hypercapnia (vs. normoxia and hyperoxia, P < 0.001) and a decrease under ACZ (vs. placebo, P < 0.001), whereas it was not modified in hyperoxia. period was shortened by exercise in all conditions (vs. rest, P < 0.01) and by hypercapnia (vs. normoxia, P < 0.05) but remained unchanged under ACZ (vs. placebo). peak power was positively related to cardiac output () and in hyperoxia (P < 0.01), in hypercapnia (P < 0.001) and under ACZ (P < 0.001). period was negatively related to and in hyperoxia (P < 0.01 and P < 0.001, respectively), in hypercapnia (P < 0.05 and P < 0.01, respectively) and under ACZ (P < 0.05 and P < 0.01, respectively). Total respiratory cycle time was the main factor responsible for changes in period. In conclusion, exercise, hypoxia, and hypercapnia increase ventilatory oscillations by increasing and , whereas ACZ decreases ventilatory instability in part by a contrasting action on O2 and CO2 sensing. An intrinsic oscillator might modulate ventilation through a complex system where peripheral chemoreflex would play a key role.
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Affiliation(s)
- Eric Hermand
- Université Paris 13 Sorbonne Paris Cité Laboratoire "Hypoxie et poumon", Bobigny, France
| | - François J Lhuissier
- Université Paris 13 Sorbonne Paris Cité Laboratoire "Hypoxie et poumon", Bobigny, France Assistance Publique-Hôpitaux de Paris, Hôpital Avicenne Service de Physiologie explorations fonctionnelles et médecine du sport, Bobigny, France
| | - Julie Larribaut
- Université Paris 13 Sorbonne Paris Cité Laboratoire "Hypoxie et poumon", Bobigny, France
| | - Aurélien Pichon
- Université Paris 13 Sorbonne Paris Cité Laboratoire "Hypoxie et poumon", Bobigny, France
| | - Jean-Paul Richalet
- Université Paris 13 Sorbonne Paris Cité Laboratoire "Hypoxie et poumon", Bobigny, France Assistance Publique-Hôpitaux de Paris, Hôpital Avicenne Service de Physiologie explorations fonctionnelles et médecine du sport, Bobigny, France
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22
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Abstract
Carbonic anhydrase (CA) inhibitors, particularly acetazolamide, have been used at high altitude for decades to prevent or reduce acute mountain sickness (AMS), a syndrome of symptomatic intolerance to altitude characterized by headache, nausea, fatigue, anorexia and poor sleep. Principally CA inhibitors act to further augment ventilation over and above that stimulated by the hypoxia of high altitude by virtue of renal and endothelial cell CA inhibition which oppose the hypocapnic alkalosis resulting from the hypoxic ventilatory response (HVR), which acts to limit the full expression of the HVR. The result is even greater arterial oxygenation than that driven by hypoxia alone and greater altitude tolerance. The severity of several additional diseases of high attitude may also be reduced by acetazolamide, including high altitude cerebral edema (HACE), high altitude pulmonary edema (HAPE) and chronic mountain sickness (CMS), both by its CA-inhibiting action as described above, but also by more recently discovered non-CA inhibiting actions, that seem almost unique to this prototypical CA inhibitor and are of most relevance to HAPE. This chapter will relate the history of CA inhibitor use at high altitude, discuss what tissues and organs containing carbonic anhydrase play a role in adaptation and maladaptation to high altitude, explore the role of the enzyme and its inhibition at those sites for the prevention and/or treatment of the four major forms of illness at high altitude.
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Affiliation(s)
- Erik R Swenson
- VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, WA, USA,
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23
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Ainslie PN, Lucas SJ, Burgess KR. Breathing and sleep at high altitude. Respir Physiol Neurobiol 2013; 188:233-56. [DOI: 10.1016/j.resp.2013.05.020] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Revised: 05/04/2013] [Accepted: 05/16/2013] [Indexed: 10/26/2022]
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24
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Salvi P, Revera M, Faini A, Giuliano A, Gregorini F, Agostoni P, Becerra CGR, Bilo G, Lombardi C, O'Rourke MF, Mancia G, Parati G. Changes in subendocardial viability ratio with acute high-altitude exposure and protective role of acetazolamide. Hypertension 2013; 61:793-9. [PMID: 23438935 DOI: 10.1161/hypertensionaha.111.00707] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
High-altitude tourism is increasingly frequent, involving also subjects with manifest or subclinical coronary artery disease. Little is known, however, on the effects of altitude exposure on factors affecting coronary perfusion. The aim of our study was to assess myocardial oxygen supply/demand ratio in healthy subjects during acute exposure at high altitude and to evaluate the effect of acetazolamide on this parameter. Forty-four subjects (21 men, age range: 24-59 years) were randomized to double-blind acetazolamide 250 mg bid or placebo. Subendocardial viability ratio and oxygen supply/demand ratio were estimated on carotid artery by means of a validated PulsePen tonometer, at sea level, before and after treatment, and after acute and more prolonged exposure to high altitude (4559 m). On arrival at high altitude, subendocardial viability ratio was reduced in both placebo (from 1.63±0.15 to 1.18±0.17; P<0.001) and acetazolamide (from 1.68±0.25 to 1.35±0.18; P<0.001) groups. Subendocardial viability ratio returned to sea level values (1.65±0.24) after 3 days at high altitude under acetazolamide but remained lower than at sea level under placebo (1.42±0.22; P<0.005 versus baseline). At high altitude, oxygen supply/demand ratio fell both under placebo (from 29.6±4.0 to 17.3±3.0; P<0.001) and acetazolamide (from 32.1±7.0 to 22.3±4.6; P<0.001), its values remaining always higher (P<0.001) on acetazolamide. Administration of acetazolamide may, thus, antagonize the reduction in subendocardial oxygen supply triggered by exposure to hypobaric hypoxia. Further studies involving also subjects with known or subclinical coronary artery disease are needed to confirm a protective action of acetazolamide on myocardial viability under high-altitude exposure.
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Affiliation(s)
- Paolo Salvi
- Department of Cardiology, San Luca Hospital, IRCCS Istituto Auxologico Italiano, Milan, Italy
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25
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Nocturnal carbon dioxide monitoring in patients with idiopathic intracranial hypertension. Clin Neurol Neurosurg 2013; 115:1379-81. [PMID: 23369399 DOI: 10.1016/j.clineuro.2012.12.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 12/21/2012] [Accepted: 12/27/2012] [Indexed: 11/24/2022]
Abstract
BACKGROUND Idiopathic intracranial hypertension may be associated with sleep apnea. This study evaluated the incidence of sleep breathing disorders in patients with idiopathic intracranial hypertension. MATERIALS AND METHODS Overnight respiratory monitoring was performed in 22 untreated patients with idiopathic intracranial pressure diagnosed at a tertiary medical center over a two-year period and 12 sex- and age-matched control subjects. Breathing measures included heart rate, respiratory rate,oxygen saturation, and continuous end-tidal capnography. Sleep quality and daily fatigue were assessed by self-report questionnaires. RESULTS Mean age of the study group was 32.6±12.2 years and of the control group, 37.0±12.9 years. Neither group had significant findings of hypoxia or hypercarbia during sleep, and there were no between-group differences in mean carbon dioxide level (patients, 35.8±4.41 mmHg; controls, 37.6±4.38 mmHg; p>0.02) or minimal oxygen saturation (96.35±1.99% and 5.69±1.71%, respectively; p>0.02). The study group had significantly more events of apnea (CO2) per hour of sleep than the control group (1.21±1.38 and 0.92±0.56, respectively; p=0.02), although values were still within normal range (<5/hr). CONCLUSION Idiopathic intracranial hypertension is not associated with a clinically significant nocturnal breathing abnormality, and hypercarbia is apparently not involved in the pathogenesis. However, it is possible that a subtle increase in paroxysmal sleep apnea (CO2) events might be sufficient to cause vasodilatation of the cerebral blood vessels, thereby increasing intracranial pressure. Screening for sleep apnea may be appropriate in idiopathic intracranial hypertension patients, and further studies are needed to clarify this issue.
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26
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Teppema LJ, Berendsen RR. Acetazolamide and cerebrovascular function at high altitude. J Physiol 2012; 590:2945-6; author reply 2947. [PMID: 22707596 DOI: 10.1113/jphysiol.2012.233569] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Verhulst SL, De Dooy J, Ramet J, Bockaert N, Van Coster R, Ceulemans B, De Backer W. Acetazolamide for severe apnea in Pitt-Hopkins syndrome. Am J Med Genet A 2012; 158A:932-4. [PMID: 22407847 DOI: 10.1002/ajmg.a.35247] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 12/21/2011] [Indexed: 11/11/2022]
Affiliation(s)
- Stijn L Verhulst
- Department of Pediatrics, Antwerp University Hospital, Edegem, Belgium.
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28
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Nussbaumer-Ochsner Y, Latshang TD, Ulrich S, Kohler M, Thurnheer R, Bloch KE. Patients with obstructive sleep apnea syndrome benefit from acetazolamide during an altitude sojourn: a randomized, placebo-controlled, double-blind trial. Chest 2011; 141:131-138. [PMID: 21659435 DOI: 10.1378/chest.11-0375] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Many patients with obstructive sleep apnea syndrome (OSA) are unable or unwilling to use continuous positive airway pressure (CPAP) therapy when traveling to the mountains for work or recreation even though they risk pronounced hypoxemia and exacerbation of sleep apnea. Because the treatment of OSA at altitude has not been established, we tested the hypothesis that acetazolamide improves hypoxemia, sleep, and breathing disturbances in otherwise untreated patients with OSA at altitude. METHODS Forty-five patients with OSA on long-term CPAP, median age 64 years, living at < 600 m underwent a placebo-controlled, double-blind, crossover trial randomized for the sequence of drug and altitude exposure (490 m, 1,860 m, and 2,590 m). Patients spent two 3-day periods at altitude and a 2-week wash-out period at < 600 m. At altitude, patients discontinued CPAP and received acetazolamide 2 × 250 mg daily or placebo. Polysomnography, vigilance, and symptoms were evaluated. RESULTS At 490 m, off CPAP, median nocturnal oxygen saturation was 93%, and the apnea/hypopnea index was 51.2/h. On placebo at 1,860 m and 2,590 m, the corresponding values were 89% and 85% and 63.6/h and 86.2/h, respectively (P < .01 vs 490 m, both instances). On acetazolamide at 1,860 m and 2,590 m, oxygen saturation was higher (91% and 88%) and apnea/hypopnea indices were lower (48.0/h and 61.4/h) than on placebo (P < .01 all instances). Acetazolamide reduced nocturnal transcutaneous Pco(2), improved sleep efficiency and subjective insomnia, and prevented excessive BP elevations at altitude. CONCLUSIONS In patients with OSA discontinuing CPAP during an altitude sojourn, acetazolamide improves oxygenation, breathing disturbances, and sleep quality by stimulating ventilation. Therefore, patients with OSA may benefit from acetazolamide at altitude if CPAP therapy is not feasible. TRIAL REGISTRY ClinicalTrials.gov; No.: NCT00714740; URL: www.clinicaltrials.gov.
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Affiliation(s)
- Yvonne Nussbaumer-Ochsner
- Sleep Disorders Center, Pulmonary Division, University Hospital of Zurich, Zurich; Center for Human Integrative Physiology, University of Zurich, Zurich
| | - Tsogyal D Latshang
- Sleep Disorders Center, Pulmonary Division, University Hospital of Zurich, Zurich; Center for Human Integrative Physiology, University of Zurich, Zurich
| | - Silvia Ulrich
- Sleep Disorders Center, Pulmonary Division, University Hospital of Zurich, Zurich; Center for Human Integrative Physiology, University of Zurich, Zurich
| | - Malcolm Kohler
- Center for Human Integrative Physiology, University of Zurich, Zurich
| | - Robert Thurnheer
- Pulmonary Division, Cantonal Hospital Munsterlingen, Munsterlingen, Switzerland
| | - Konrad E Bloch
- Sleep Disorders Center, Pulmonary Division, University Hospital of Zurich, Zurich; Center for Human Integrative Physiology, University of Zurich, Zurich.
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Teppema LJ, van Dorp ELA, Dahan A. Arterial [H+] and the ventilatory response to hypoxia in humans: influence of acetazolamide-induced metabolic acidosis. Am J Physiol Lung Cell Mol Physiol 2009; 298:L89-95. [PMID: 19880504 DOI: 10.1152/ajplung.00255.2009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this study, we investigated possible separate effects of H+ ions and CO2 on hypoxic sensitivity in humans. We also examined whether hypoxic sensitivity, conventionally defined as the ratio of (hypoxic - normoxic) ventilation over (hypoxic - normoxic) Hb oxygen saturation can also be estimated by taking the ratio (hypoxic - normoxic) ventilation over (logPa(O2) hypoxia - logPa(O2) normoxia), enabling one to measure the hypoxic response independently from potential confounding influences of changes in position of the Hb oxygen saturation curve. We used acetazolamide to induce a metabolic acidosis. To determine the acute hypoxic response (AHR), we performed step decreases in end-tidal Po2 to approximately 50 Torr lasting 5 min each at three different constant end-tidal Pco2 levels. Nine subjects ingested 250 mg of acetazolamide or placebo every 8 h for 3 days in a randomized double-blind crossover design. The metabolic acidosis was accompanied by a rise in ventilation, a substantial fall in Pa(CO2), and a parallel leftward shift of the ventilatory CO2 response curve. In placebo, CO2 induced equal relative increases in hypoxic sensitivity (O2-CO2 interaction) regardless of the way it was defined. Acetazolamide shifted the response line representing the relationship between hypoxic sensitivity and arterial [H+] ([H+](a)) to higher values of [H+](a) without altering its slope, indicating that it did not affect the O2-CO2 interaction. So, in contrast to an earlier belief, CO2 and H+ have separate effects on hypoxic sensitivity. This was also supported by the finding that infusion of bicarbonate caused a leftward shift of the hypoxic sensitivity-[H+](a) response lines in placebo and acetazolamide. A specific inhibitory effect of acetazolamide on hypoxic sensitivity was not demonstrated.
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Affiliation(s)
- Luc J Teppema
- Department of Anesthesiology, Leiden University Medical Center, PO Box 9600 2300 RC, Leiden, The Netherlands.
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Kiwull-Schöne HF, Li Y, Kiwull PJ, Teppema LJ. Methazolamide does not impair respiratory work performance in anesthetized rabbits. Am J Physiol Regul Integr Comp Physiol 2009; 297:R648-54. [DOI: 10.1152/ajpregu.00134.2009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In human medicine, the carbonic anhydrase (CA) inhibitor acetazolamide is used to treat irregular breathing disorders. Previously, we demonstrated in the rabbit that this substance stabilized closed-loop gain properties of the respiratory control system, but concomitantly weakened respiratory muscles. Among others, the highly diffusible CA-inhibitor methazolamide differs from acetazolamide in that it fails to activate Ca2+-dependent potassium channels in skeletal muscles. Therefore, we aimed to find out, whether or not methazolamide may exert attenuating adverse effects on respiratory muscle performance as acetazolamide. In anesthetized spontaneously breathing rabbits ( n = 7), we measured simultaneously the CO2 responses of tidal phrenic nerve activity, tidal transpulmonary pressure changes, and tidal volume before and after intravenous application of methazolamide at two mean (± SE) cumulative doses of 3.5 ± 0.1 and 20.8 ± 0.4 mg/kg. Similar to acetazolamide, low- and high-dose methazolamide enhanced baseline ventilation by 52 ± 10% and 166 ± 30%, respectively ( P < 0.01) and lowered the base excess in a dose-dependent manner by up to 8.3 ± 0.9 mmol/l ( P < 0.001). The transmission of a CO2-induced rise in phrenic nerve activity into volume and/or pressure and, hence, respiratory work performance was 0.27 ± 0.05 ml·kg−1·kPa·unit−1 under control conditions, but remained unchanged upon low- or high-dose methazolamide, at 0.30 ± 0.06 and 0.28 ± 0.07 ml·kg−1·kPa·unit−1, respectively. We conclude that methazolamide does not cause respiratory muscle weakening at elevated levels of ventilatory drive. This substance (so far not used for medication of respiratory diseases) may thus exert stabilizing influences on breathing control without adverse effects on respiratory muscle function.
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Küpper TEAH, Strohl KP, Hoefer M, Gieseler U, Netzer CM, Netzer NC. Low-dose theophylline reduces symptoms of acute mountain sickness. J Travel Med 2008; 15:307-14. [PMID: 19006503 DOI: 10.1111/j.1708-8305.2008.00228.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Headache, nausea, and sleeplessness at altitude [acute mountain sickness (AMS)] are major health problems for several million mountain recreationists who ascend to high altitudes each year. We aimed to test the efficacy of low-dose, slow-release theophylline for the prevention of AMS in a placebo-controlled, double-blind, randomized trial. METHODS Twenty healthy male volunteers (mean age 34.7 y) were randomized (random allocation) to receive either 300 mg theophylline daily or placebo 5 days prior, during ascent, and during a stay at 4,559 m altitude. AMS symptoms were collected using the Lake Louise Score on each day during ascent and at high altitude. A 12-channel sleep recorder recorded sleep and breathing parameters during the first night at 4,559 m. Theophylline serum levels were drawn prior to the sleep study. RESULTS Seventeen completed the entire study. Theophylline (n = 9) compared to placebo (n = 8) significantly reduced AMS symptoms at 4,559 m (Lake Louise Score: 1.5 +/- 0.5 vs placebo 2.3 +/- 2.37; p < 0.001), events of periodic breathing (34.3/h vs placebo 74.2/h; p < 0.05), and oxygen desaturations (62.3/h vs placebo 121.6/h; p < 0.01). No significant differences in sleep efficiency or sleep structure were present in the two groups. No adverse drug effects were reported. CONCLUSIONS Low-dose, slow-release theophylline reduces symptoms of AMS in association with alleviation of events of periodic breathing and oxygen desaturations.
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Affiliation(s)
- Thomas E A H Küpper
- Hermann Buhl Institute for Hypoxia Research and Sleep Medicine, Paracelsus Medical University Salzburg, Bad Aibling, Germany.
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Collier DJ, Nickol AH, Milledge JS, van Ruiten HJA, Collier CJ, Swenson ER, Datta A, Wolff CB. Alveolar Pco2 oscillations and ventilation at sea level and at high altitude. J Appl Physiol (1985) 2008; 104:404-15. [DOI: 10.1152/japplphysiol.00166.2007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study examines the potential for a ventilatory drive, independent of mean Pco2, but depending instead on changes in Pco2 that occur during the respiratory cycle. This responsiveness is referred to here as “dynamic ventilatory sensitivity.” The normal, spontaneous, respiratory oscillations in alveolar Pco2 have been modified with inspiratory pulses approximating alveolar Pco2 concentrations, both at sea level and at high altitude (5,000 m, 16,400 ft.). All tests were conducted with subjects exercising on a cycle ergometer at 60 W. The pulses last about half the inspiratory duration and are timed to arrive in the alveoli during early or late inspiration. Differences in ventilation, which then occur in the face of similar end-tidal Pco2 values, are taken to result from dynamic ventilatory sensitivity. Highly significant ventilatory responses (early pulse response greater than late) occurred in hypoxia and normoxia at sea level and after more than 4 days at 5,000 m. The response at high altitude was eliminated by normalizing Po2 and was reduced or eliminated with acetazolamide. No response was present soon after arrival (<4 days) at base camp, 5,000 m, on either of two high-altitude expeditions (BMEME, 1994, and Kanchenjunga, 1998). The largest responses at 5,000 m were obtained in subjects returning from very high altitude (7,100–8,848 m). The present study confirms and extends previous investigations that suggest that alveolar Pco2 oscillations provide a feedback signal for respiratory control, independent of changes in mean Pco2, suggesting that natural Pco2 oscillations drive breathing in exercise.
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Moraga FA, Flores A, Serra J, Esnaola C, Barriento C. Ginkgo biloba Decreases Acute Mountain Sickness in People Ascending to High Altitude at Ollagüe (3696m) in Northern Chile. Wilderness Environ Med 2007; 18:251-7. [DOI: 10.1580/06-weme-or-062r2.1] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Factors of lowered respiratory CO2 sensitivity by acetazolamide in anaesthetized rabbits. Open Med (Wars) 2006. [DOI: 10.2478/s11536-006-0034-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AbstractThe carbonic anhydrase (CA) inhibitor acetazolamide is a classic drug to treat patients with breathing disorders. Recent studies in rabbits showed that low-dose acetazolamide (not causing appreciable inhibition of red cell CA) significantly weakened respiratory muscle performance, accompanied by diminished ventilatory CO2-sensitivity, which implies stabilizing loop-gain properties. Now is aimed to explore the interaction of these factors under conditions of complete CA-inhibition by acetazolamide in a higher dose-range.In anesthetized rabbits (N=7), acetazolamide (up to 75 mg·kg−1) distinctly lowered the base excess (to-7.6 ± 0.9mM, mean ± SEM) without respiratory compensation of arterial pH. Ventilatory CO2-sensitivity was nearly abolished to 15.1 ± 5.2% of control, but the transmission of a CO2-mediated rise in tidal phrenic activity into respiratory work was only reduced by 51.6 ± 6.4%, P < 0.001, not very much more than (~38%) already observed at low-doses.Thus, the large reduction of ventilatory CO2-sensitivity in the high-dose range cannot be ascribed to respiratory muscle weakening, but rather may relate to complete inhibition of red cell CA. Conversely, CA-inhibition may not be the only cause for the weakening effect of acetazolamide on (respiratory) muscles. Adverse effects on respiratory muscles, impaired CO2-transport and acid-base imbalance may limit to make use of stabilizing effects on breathing control functions by high-dose acetazolamide.
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Leaf DE, Goldfarb DS. Mechanisms of action of acetazolamide in the prophylaxis and treatment of acute mountain sickness. J Appl Physiol (1985) 2006; 102:1313-22. [PMID: 17023566 DOI: 10.1152/japplphysiol.01572.2005] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Acetazolamide, a potent carbonic anhydrase (CA) inhibitor, is the most commonly used and best-studied agent for the amelioration of acute mountain sickness (AMS). The actual mechanisms by which acetazolamide reduces symptoms of AMS, however, remain unclear. Traditionally, acetazolamide's efficacy has been attributed to inhibition of CA in the kidneys, resulting in bicarbonaturia and metabolic acidosis. The result is offsetting hyperventilation-induced respiratory alkalosis and allowance of chemoreceptors to respond more fully to hypoxic stimuli at altitude. Studies performed on both animals and humans, however, have shown that this explanation is unsatisfactory and that the efficacy of acetazolamide in the context of AMS is likely due to a multitude of effects. This review summarizes the known systemic effects of acetazolamide and incorporates them into a model encompassing several factors that are likely to play a key role in the drug's efficacy. Such factors include not only metabolic acidosis resulting from renal CA inhibition but also improvements in ventilation from tissue respiratory acidosis, improvements in sleep quality from carotid body CA inhibition, and effects of diuresis.
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Kiwull-Schöne H, Teppema L, Wiemann M, Kiwull P. Loop gain of respiratory control upon reduced activity of carbonic anhydrase or Na+/H+ exchange. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2006; 580:239-44; discussion 351-9. [PMID: 16683726 DOI: 10.1007/0-387-31311-7_37] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
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Basnyat B, Gertsch JH, Holck PS, Johnson EW, Luks AM, Donham BP, Fleischman RJ, Gowder DW, Hawksworth JS, Jensen BT, Kleiman RJ, Loveridge AH, Lundeen EB, Newman SL, Noboa JA, Miegs DP, O'Beirne KA, Philpot KB, Schultz MN, Valente MC, Wiebers MR, Swenson ER. Acetazolamide 125 mg BD Is Not Significantly Different from 375 mg BD in the Prevention of Acute Mountain Sickness: The Prophylactic Acetazolamide Dosage Comparison for Efficacy (PACE) Trial. High Alt Med Biol 2006; 7:17-27. [PMID: 16544963 DOI: 10.1089/ham.2006.7.17] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
750 mg per day of acetazolamide in the prevention of acute mountain sickness (AMS), as recommended in the meta-analysis published in 2000 in the British Medical Journal, may be excessive and is controversial. To determine if the efficacy of low-dose acetazolamide 125 mg bd (250 mg), as currently used in the Himalayas, is significantly different from 375 mg bd (750 mg) of acetazolamide in the prevention of AMS, we designed a prospective, double-blind, randomized, placebo-controlled trial. The participants were sampled from a diverse population of (non-Nepali) trekkers at Namche Bazaar (3440 m) in Nepal on the Everest trekking route as they ascended to study midpoints (4280 m/4358 m) and the endpoint, Lobuje (4928 m), where data were collected. Participants were randomly assigned to receive 375 mg bd of acetazolamide (82 participants), 125 mg bd of acetazolamide (74 participants), or a placebo (66 participants), beginning at 3440 m for up to 6 days as they ascended to 4928 m. The results revealed that composite AMS incidence for 125 mg bd was similar to the incidence for 375 mg bd (24% vs. 21%, 95% confidence interval, -12.6%, 19.8%), in contrast to significantly greater AMS (51%) observed in the placebo group (95% confidence interval for differences: 8%, 46%; 12%, 49% for low and high comparisons, respectively). Both doses of acetazolamide improved oxygenation equally (82.9% for 250 mg daily and 82.8% for 750 mg daily), while placebo endpoint oxygen saturation was significantly less at 80.7% (95% confidence interval for differences: 0.5%, 3.9% and 0.4%, 3.7% for low and high comparisons, respectively). There was also more paresthesia in the 375-mg bd group (p < 0.02). We conclude that 125 mg bd of acetazolamide is not significantly different from 375 mg bd in the prevention of AMS; 125 mg bd should be considered the preferred dosage when indicated for persons ascending to altitudes above 2500 m.
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Affiliation(s)
- Buddha Basnyat
- Himalayan Rescue Association and Nepal International Clinic, Kathmandu, Nepal
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Abstract
New arrivals to altitude commonly experience poor-quality sleep. These complaints are associated with increased fragmentation of sleep by frequent brief arousals, which are in turn linked to periodic breathing. Changes in sleep architecture include a shift toward lighter sleep stages, with marked decrements in slow-wave sleep and with variable decreases in rapid eye movement (REM) sleep. Respiratory periodicity at altitude reflects alternating respiratory stimulation by hypoxia and subsequent inhibition by hyperventilation-induced hypocapnia. Increased hypoxic ventilatory responsiveness and loss of regularization of breathing during sleep contribute to the occurrence of periodicity. Interventions that improve sleep quality at high altitude include acetazolamide and benzodiazepines.
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Affiliation(s)
- John V Weil
- Cardiovascular Pulmonary Research Laboratory, University of Colorado Health Sciences Center, 4200 East NinthAvenue, Denver 80262, USA.
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Teppema LJ, Dahan A. Low-dose acetazolamide reduces the hypoxic ventilatory response in the anesthetized cat. Respir Physiol Neurobiol 2004; 140:43-51. [PMID: 15109927 DOI: 10.1016/j.resp.2004.01.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2004] [Indexed: 12/31/2022]
Abstract
Low intravenous dose acetazolamide causes a decrease in steady-state CO(2) sensitivity of both the peripheral and central chemoreflex loops. The effect, however, on the steady-state hypoxic response is unknown. In the present study, we measured the effect of 4 mg x kg(-1) acetazolamide (i.v.) on the isocapnic steady-state hypoxic response in anesthetized cats. Before and after acetazolamide administration, the eucapnic steady-state hypoxic response in these animals was measured by varying inspiratory P(O2) levels to achieve steady-state Pa(O2) levels between hyperoxia Pa(O2) approximately 55 kPa, approximately 412 mmHg) and hypoxia (Pa(O2) approximately 7 kPa, approximately 53 mmHg). The hypoxic ventilatory response was described by the exponential function V(I) = G exp (-DP(o2) + A with an overall hypoxic sensitivity G, a shape parameter D and ventilation during hyperoxia A. Acetazolamide significantly reduced G from 3.057 +/- 1.616 to 1.573 +/- 0.8361 min(-1) (mean +/- S D). Parameter A increased from 0.903 +/- 0.257 to 1.193 +/- 0.321 min(-1), while D remained unchanged. The decrease in overall hypoxic sensitivity by acetazolamide is probably mediated by an inhibitory effect on the carotid bodies and may have clinical significance in the treatment of sleep apneas, particularly those cases that are associated with an increased ventilatory sensitivity to oxygen and/or carbon dioxide.
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Affiliation(s)
- Luc J Teppema
- Department of Anesthesiology, Leiden University Medical Center, PO Box 9604, 2300 RC Leiden, The Netherlands.
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Sightings. High Alt Med Biol 2002. [DOI: 10.1089/15270290260131876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Abstract
Sleep at high altitude is characterized by poor subjective quality, increased awakenings, frequent brief arousals, marked nocturnal hypoxemia, and periodic breathing. A change in sleep architecture with an increase in light sleep and decreasing slow-wave and REM sleep have been demonstrated. Periodic breathing with central apnea is almost universally seen amongst sojourners to high altitude, although it is far less common in long-standing high altitude dwellers. Hypobaric hypoxia in concert with periodic breathing appears to be the principal cause of sleep disruption at altitude. Increased sleep fragmentation accounts for the poor sleep quality and may account for some of the worsened daytime performance at high altitude. Hypoxic sleep disruption contributes to the symptoms of acute mountain sickness. Hypoxemia at high altitude is most severe during sleep. Acetazolamide improves sleep, AMS symptoms, and hypoxemia at high altitude. Low doses of a short acting benzodiazepine (temazepam) may also be useful in improving sleep in high altitude.
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Affiliation(s)
- Himanshu Wickramasinghe
- Pulmonary and Intensive Care Section, Department of Internal Medicine, Loma Linda University School of Medicine, Loma Linda, California
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Swenson ER. Respiratory and renal roles of carbonic anhydrase in gas exchange and acid-base regulation. EXS 2001:281-341. [PMID: 11268521 DOI: 10.1007/978-3-0348-8446-4_15] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- E R Swenson
- VA Puget Sound Health Care System, 1660 S Columbian Way, Seattle, WA 98108, USA
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Kiwull-Schöne HF, Teppema LJ, Kiwull PJ. Low-dose acetazolamide does affect respiratory muscle function in spontaneously breathing anesthetized rabbits. Am J Respir Crit Care Med 2001; 163:478-83. [PMID: 11179126 DOI: 10.1164/ajrccm.163.2.9911075] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Patients with chronic obstructive pulmonary diseases (COPD) and/or central sleep apnea are sometimes treated with the carbonic anhydrase inhibitor acteazolamide to improve blood gas values. Studies have shown that this agent may have a complicated effect on lung ventilation, because carbonic anhydrase has a widespread distribution within the body, particularly in tissues involved in the control of breathing. To investigate whether acetazolamide may have (neuro)muscular effects on respiration, we measured the responses of ventilation, phrenic nerve activity, and transpulmonary pressure to changes in arterial PCO2 before and after intravenous administration of a low-dose (4.6 +/- 0.2 mg x kg(-1), mean +/- SEM) of this inhibitor in anesthetized spontaneously breathing rabbits. The agent decreased the mean resting end-tidal PCO2 by 1 kPa and increased ventilation from 258 +/- 15 to 292 +/- 14 ml x min(-1) x kg(-1) (p < or = 0.05). The ventilatory and tidal volume responses to CO2 were reduced, and the response curves were shifted to lower PCO2 values. At the level of phrenic activity, however, the response was shifted leftward without altering CO2 sensitivity. With an unchanged lung compliance, the slopes of the relationships between tidal volume and phrenic activity and that between the tidal change in transpulmonary pressure and phrenic amplitude were both reduced by about 40%, indicating an action of acetazolamide on (neuro)muscular level. The results raise the suggestion that treatment of some hypercapnic COPD patients with acetazolamide may have undesired clinical implications, particularly in those with already weakened respiratory muscles.
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Affiliation(s)
- H F Kiwull-Schöne
- Department of Physiology, Faculty of Medicine, Ruhr-University, Bochum, Germany
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Teppema LJ, Dahan A. Acetazolamide and breathing. Does a clinical dose alter peripheral and central CO(2) sensitivity? Am J Respir Crit Care Med 1999; 160:1592-7. [PMID: 10556126 DOI: 10.1164/ajrccm.160.5.9903088] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Improvement of blood gases with the carbonic anhydrase inhibitor acetazolamide in some patients with chronic obstructive pulmonary disease (COPD) is believed to result from an effect on the ventilatory control system. Carbonic anhydrase is ubiquitously present within the body, particularly in tissues involved in the control of breathing. Because low inhibitor concentrations are sufficient to block the enzyme in many tissues, it is of interest to document the effect of clinical doses of acetazolamide on the CO(2) sensitivities of the peripheral and central chemoreflex loops. In this study we measured the effect of chronic acetazolamide (250 mg by way of mouth, every 8 h during 3 days) on the dynamic ventilatory response to step changes in end-tidal PCO(2) in nine healthy volunteers. Data were analyzed using a two-compartment model comprising a fast peripheral and slow central compartment, enabling us to separate drug effects on the peripheral and central chemoreflex loops, respectively. Compared with placebo, acetazolamide did not change the CO(2) sensitivities and time constants of both chemoreflex loops. However, mean (+/- SD) resting ventilation increased from 12.22 +/- 2.41 to 14.01 +/- 1.85 L. min(-1), resulting in a decrease in end-tidal PCO(2) from 40.0 +/- 4.7 to 33.3 +/- 3.5 mm Hg. Base excess decreased from -0.08 +/- 1.20 to -7.48 +/- 2.07 mmol. L(-1), indicating metabolic acidosis and explaining a leftward shift of the CO(2) response curve by 7.3 mm Hg. Possible clinical implications of these results are discussed.
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Affiliation(s)
- L J Teppema
- Department of Physiology, Leiden University Medical Center, Leiden, The Netherlands.
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Verbraecken J, Willemen M, De Cock W, Coen E, Van de Heyning P, De Backer W. Central sleep apnea after interrupting longterm acetazolamide therapy. RESPIRATION PHYSIOLOGY 1998; 112:59-70. [PMID: 9696283 DOI: 10.1016/s0034-5687(98)00010-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
One month administration of acetazolamide (ACET) (at sea level) improves periodic breathing and decreases the number of central apneas (CA) (De Backer et al., 1995 Am. J. Respir. Crit. Care Med. 151, 87-91) in nonhypercapnic central apnea syndrome. It remains unclear whether cessation of therapy would provoke recurrence of symptoms. In the present study we evaluated the number of CA after 1 and 6 months interruption of ACET therapy. Eight patients with central sleep apnea were included [central apnea index (CAI) > 5 or apnea and hypopnea index (AHI) > 10 and obstructive apnea index (OAI) < 5]. Polysomnography was repeated once after 1 month treatment (N2), after 1 month off treatment (N3) and after 6 months off treatment. CAI (25 +/- 10 at N1) decreased during N2 (4 +/- 2) and N3 (5 +/- 3) and remained low after N4 (3 +/- 1). However an increase in the number of obstructive apneas and central hypopneas could be observed together with a shift from central apnea to hypopnea after N4. Maybe ACET induces a long lasting resetting of the CO2 threshold which is still present after interruption of the therapy.
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Affiliation(s)
- J Verbraecken
- Department of Respiratory Medicine, University of Antwerp, Wilrijk-Antwerp, Belgium
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Abstract
BACKGROUND Reduced oxygen availability at high altitude is associated with increased neonatal and infant mortality. We hypothesized that native Tibetan infants, whose ancestors have inhabited the Himalayan Plateau for approximately 25,000 years, are better able to maintain adequate oxygenation at high altitude than Han infants, whose ancestors moved to Tibet from lowland areas of China after the Chinese military entered Tibet in 1951. METHODS We compared arterial oxygen saturation, signs of hypoxemia, and other indexes of neonatal wellbeing at birth and during the first four months of life in 15 Tibetan infants and 15 Han infants at 3658 m above sea level in Lhasa, Tibet. The Han mothers had migrated from lowland China about two years previously. A pulse oximeter was placed on each infant's foot to provide measurements of arterial oxygen saturation distal to the ductus arteriosus. RESULTS The two groups had similar gestational ages (about 38.9 weeks) and Apgar scores. The Han infants had lower birth weights (2773 +/- 92 g) than the Tibetan infants (3067 +/- 107 g), higher concentrations of cord-blood hemoglobin (18.6 +/- 0.8 g per deciliter, vs. 16.7 +/- 0.4 in the Tibetans), and higher hematocrit values (58.5 +/- 2.4 percent, vs. 51.4 +/- 1.2 percent in the Tibetans). In both groups, arterial oxygen saturation was highest in the first two days after birth and was lower when the infants were asleep than when they were awake. Oxygen saturation values were lower in the Han than in the Tibetan infants at all times and under all conditions during all activities. The values declined in the Han infants from 92 +/- 3 percent while they were awake and 90 +/- 5 percent during quiet sleep at birth to 85 +/- 4 percent while awake and 76 +/- 5 percent during quiet sleep at four months of age. In the Tibetan infants, oxygen saturation values averaged 94 +/- 2 percent while they were awake and 94 +/- 3 percent during quiet sleep at birth and 88 +/- 2 percent while awake and 86 +/- 5 percent during quiet sleep at four months. Han infants had clinical signs of hypoxemia--such as cyanosis during sleep and while feeding--more frequently than Tibetans. CONCLUSIONS In Lhasa, Tibet, we found that Tibetan newborns had higher arterial oxygen saturation at birth and during the first four months of life than Han newborns. Genetic adaptations may permit adequate oxygenation and confer resistance to the syndrome of pulmonary hypertension and right-heart failure (subacute infantile mountain sickness).
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Affiliation(s)
- S Niermeyer
- Department of Pediatrics, University of Colorado School of Medicine, Denver, USA
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Cordoba E, Gerhardt T, Rojas M, Duara S, Bancalari E. Comparison of the effects of acetazolamide and aminophylline on apnea incidence and on ventilatory response to CO2 in preterm infants. Pediatr Pulmonol 1994; 17:291-5. [PMID: 8058422 DOI: 10.1002/ppul.1950170505] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Acetazolamide (ACTZ) reduces sleep apnea in adults exposed to high altitude and augments the ventilatory response to CO2. In order to determine the effect of ACTZ on the ventilatory response to CO2 and the incidence of apnea in preterm infants, 7 infants (BW, 1070 +/- 191 g; postnatal age, 9 +/- 7 days) were randomized to receive ACTZ (5 mg/kg/dose Q6h for 36 hr) and 7 infants (BW, 1092 +/- 292 g; post-natal age, 5 +/- 2 days) received aminophylline (AMINO; 8 mg/kg bolus then 2.5 mg/kg Q12h for 36 hr). Minute ventilation (VE), end-tidal CO2 (PETCO2), ventilatory response to CO2, number of apneic episodes (> or = 15 sec duration), and arterial blood gases were measured before and 24-36 hr after starting therapy. In the AMINO group there was a significant decrease in apnea frequency from 6 +/- 1 to 2 +/- 2 episodes over an 8 hr epoch (P < 0.05), while no significant change was observed in the ACTZ group. The end-tidal CO2 decreased significantly from 44 +/- 7 to 38 +/- 6 mmHg in the AMINO group and from 47 +/- 5 to 36 +/- 5 mmHg in the ACTZ (P < 0.05), which lead to a shift to the left of the CO2-response curve in both groups. The slope of the CO2 response curve did not change significantly in the AMINO group and decreased in the ACTZ group. There was a significant decrease of pH from 7.43 to 7.26 in the ACTZ group, whereas in the AMINO group pH increased from 7.38 to 7.44.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- E Cordoba
- Department of Pediatrics, University of Miami School of Medicine, Florida
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