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Musselwhite MN, Shen TY, Rose MJ, Iceman KE, Poliacek I, Pitts T, Bolser DC. THE INFLUENCE OF CO 2 ON SPATIOTEMPORAL FEATURES OF MECHANICALLY INDUCED COUGH IN ANESTHETIZED CATS. Respir Physiol Neurobiol 2022; 307:103964. [PMID: 36174962 DOI: 10.1016/j.resp.2022.103964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 08/10/2022] [Accepted: 09/19/2022] [Indexed: 11/27/2022]
Abstract
Effective cough requires a significant increase in lung volume used to produce the shear forces on the airway to clear aspirated material. This increase in tidal volume during cough, along with an increase in tidal frequency during bouts of paroxysmal cough produces profound hyperventilation and thus reduces arterial CO2. While there are several reports in the literature regarding the effects of hypercapnia, hyperoxia, and hypoxia on cough, there is little research quantifying the effects of hypocapnia on the cough reflex. We hypothesized that decreased CO2 would enhance coughing. In 12 spontaneously breathing adult male cats, we compared bouts of prolonged mechanically stimulated cough, in which cough induced hyperventilation (CHV) was allowed to occur, with isocapnic cough trials where we maintained eupneic end-tidal CO2 by adding CO2 to the inspired gas. Isocapnia slightly increased cough number and decreased esophageal pressures with no change in EMG magnitudes or phase durations. The cough-to-eupnea transition was also analyzed between CHV, isocapnia, and a third group of animals that were mechanically hyperventilated to apnea. The transition to eupnea was highly sensitive to added CO2, and CHV apneas were much shorter than those produced by mechanical hyperventilation. We suggest that the cough pattern generator is relatively insensitive to CHV. In the immediate post-cough period, the appearance of breathing while CO2 is very low suggests a transient reduction in apneic threshold following a paroxysmal cough bout.
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Affiliation(s)
- M Nicholas Musselwhite
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida. 1333 Center Dr, Gainesville, Florida, 32603, United States of America.
| | - Tabitha Y Shen
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida. 1333 Center Dr, Gainesville, Florida, 32603, United States of America
| | - Melanie J Rose
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida. 1333 Center Dr, Gainesville, Florida, 32603, United States of America
| | - Kimberly E Iceman
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, College of Medicine, University of Louisville. 511 S Floyd St, MDR 616, Louisville, Kentucky, 40202, United States of America
| | - Ivan Poliacek
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics. Malá hora 4A, 036 01 Martin-Záturčie, Slovakia
| | - Teresa Pitts
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, College of Medicine, University of Louisville. 511 S Floyd St, MDR 616, Louisville, Kentucky, 40202, United States of America.
| | - Donald C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida. 1333 Center Dr, Gainesville, Florida, 32603, United States of America
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Mt Everest Base Camp Medical Clinic “Everest ER”: Epidemiology of Medical Events During the First 10 Years of Operation. Wilderness Environ Med 2015; 26:4-10. [DOI: 10.1016/j.wem.2014.07.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 06/24/2014] [Accepted: 07/21/2014] [Indexed: 11/24/2022]
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Abstract
Mountains all over the world are attracting a steadily growing number of visitors due to the increasing number of cheap flights; the construction of new roads, railways, and cable cars; and commercial offers of trekking tours and expeditions to attempt even the world's highest peaks. However, one must not forget that mountains are typically inhospitable areas characterised by cold and hypoxic environments and rapidly changing weather and track conditions associated with a relatively high risk of accidents and emergencies. Beside the objective hazards, subjective hazards, for example physical fitness and health status, mountaineering skills, and equipment, contribute substantially to the risk. Whereas in some regions, for example the Alps, rescue operations and medical emergency interventions can be performed rapidly and effectively, this is absolutely not the case in most of the very remote areas and on very high mountains. Therefore, the understanding of the risk associated with the various modes of mountaineering as well as knowledge about how to optimise prevention is of the utmost importance. Ultimately, it is the informed mountaineer who has to decide whether the risks are acceptable or not. Continuing joint efforts of scientists, medical and alpine institutions, expedition organisers, and mountaineers will help to make high-altitude mountaineering safer.
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Affiliation(s)
- Günther Sumann
- Department of Anesthesiology and Critical Care Medicine, District hospital, Voecklabruck, Austria
- Austrian Society for High Altitude and Alpine Medicine, Innsbruck, Austria
| | - Thomas Hochholzer
- Austrian Society for High Altitude and Alpine Medicine, Innsbruck, Austria
- Department of Sport Science, Medical Section, University of Innsbruck, Innsbruck, Austria
- Privat Hospital Hochrum, Innsbruck, Austria
| | - Martin Faulhaber
- Austrian Society for High Altitude and Alpine Medicine, Innsbruck, Austria
- Department of Sport Science, Medical Section, University of Innsbruck, Innsbruck, Austria
| | - Martin Burtscher
- Austrian Society for High Altitude and Alpine Medicine, Innsbruck, Austria
- Department of Sport Science, Medical Section, University of Innsbruck, Innsbruck, Austria
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Bauer I. Australian senior adventure travellers to Peru: Maximising older tourists' travel health experience. Travel Med Infect Dis 2012; 10:59-68. [PMID: 22459635 DOI: 10.1016/j.tmaid.2012.03.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2011] [Revised: 02/29/2012] [Accepted: 03/05/2012] [Indexed: 11/16/2022]
Abstract
Financially comfortable, with ample spare time and much better health, older people travel more than ever and to more adventurous destinations. Taking Australian senior adventure travellers to Peru as an example, travel health preparations need to take into account the phenomenon 'senior traveller', the destination with its attractions and challenges, and age-related changes and restrictions. The need for routine travel health advice, vaccinations and prophylaxis remains unchanged. However, more emphasis should be placed on locality-specific issues so that age-appropriate advice and preparations maximize the chances for a safe and memorable travel experience.
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Affiliation(s)
- Irmgard Bauer
- School of Nursing, Midwifery and Nutrition, James Cook University, Townsville, QLD 4811, Australia.
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Lavorini F, Fontana GA, Chellini E, Magni C, Duranti R, Widdicombe J. Desensitization of the cough reflex by exercise and voluntary isocapnic hyperpnea. J Appl Physiol (1985) 2010; 108:1061-8. [DOI: 10.1152/japplphysiol.00423.2009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Little is known about the effects of exercise on the sensory and cognitive aspects of coughing evoked by inhalation of tussigenic agents. The threshold for the cough reflex induced by inhalation of increasing nebulizer outputs of ultrasonically nebulized distilled water (fog), an index of cough reflex sensitivity, was assessed in twelve healthy humans in control conditions, during exercise and during voluntary isocapnic hyperpnea (VIH) at the same ventilatory level as the exercise. The intensity of the urge to cough (UTC), a cognitive component of coughing, was recorded throughout the trials on a linear scale. The relationships between inhaled fog nebulizer outputs and the correspondingly evoked UTC values, an index of the perceptual magnitude of the UTC sensitivity, were also calculated. Cough appearance was always assessed audiovisually. At an exercise level of 80% of anaerobic threshold, the median cough threshold was increased from a control value of 0.73 to 2.22 ml/min ( P < 0.01), i.e., cough sensitivity was downregulated. With VIH, the threshold increased from 0.73 to 2.22 ml/min ( P < 0.01), a similar downregulation. With exercise and VIH compared with control, mean UTC values at cough threshold were unchanged, i.e., control, 3.83 cm; exercise, 3.12 cm; VIH, 4.08 cm. The relationship of the fog nebulizer output/UTC value was linear in control conditions and logarithmic during both exercise and VIH. The perception of the magnitude of the UTC seems to be influenced by signals or sensations arising from exercising limb and thoracic muscles and/or by higher nervous (cortical) mechanisms. The results indicate that the adjustments brought into action by exercise-induced or voluntary hyperpnea exert inhibitory influences on the sensory and cognitive components of fog-induced cough.
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Affiliation(s)
- Federico Lavorini
- Department of Internal Medicine, Respiratory Medicine and Cell Therapy, University of Florence, Florence, Italy
| | - Giovanni A. Fontana
- Department of Internal Medicine, Respiratory Medicine and Cell Therapy, University of Florence, Florence, Italy
| | - Elisa Chellini
- Department of Internal Medicine, Respiratory Medicine and Cell Therapy, University of Florence, Florence, Italy
| | - Chiara Magni
- Department of Internal Medicine, Respiratory Medicine and Cell Therapy, University of Florence, Florence, Italy
| | - Roberto Duranti
- Department of Internal Medicine, Respiratory Medicine and Cell Therapy, University of Florence, Florence, Italy
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Mason NP, Petersen M, Mélot C, Kim EV, Aldashev A, Sarybaev A, Mirrakhimov MM, Naeije R. Changes in Plasma Bradykinin Concentration and Citric Acid Cough Threshold at High Altitude. Wilderness Environ Med 2009; 20:353-8. [DOI: 10.1580/1080-6032-020.004.0353] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Thompson AR, Baillie JK, Bates MG, Schnopp MF, Simpson A, Partridge RW, Drummond GB, Mason NP. The citric acid cough threshold and the ventilatory response to carbon dioxide on ascent to high altitude. Respir Med 2009; 103:1182-8. [DOI: 10.1016/j.rmed.2009.02.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2008] [Revised: 02/10/2009] [Accepted: 02/12/2009] [Indexed: 11/24/2022]
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Cingi C, Erkan AN, Rettinger G. Ear, nose, and throat effects of high altitude. Eur Arch Otorhinolaryngol 2009; 267:467-71. [PMID: 19551397 DOI: 10.1007/s00405-009-1016-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Accepted: 05/26/2009] [Indexed: 01/22/2023]
Abstract
High altitude changes human physiology and can result in illnesses such as acute mountain sickness, high-altitude cerebral edema, and high-altitude pulmonary edema. The physiological impacts of high-altitude illnesses occur secondary to extravasation of fluid from the intravascular space into the extravascular space during a rapid ascent. Headache, hearing disturbances, vestibular disturbances, epistaxis, sleep apnea, coughing, respiratory tract infections, and nasal obstruction are main ear, nose, and throat complaints of individuals travelling to high altitude. These complaints can cause delays or cancelations in a person's climbing plans. In this article, we review the ear, nose, and throat effects of high altitude based on the relevant literature.
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Affiliation(s)
- Cemal Cingi
- Department of Otorhinolaryngology, Osmangazi University, Eskişehir, Turkey
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Widdicombe J, Fontana G, Gibson P. Workshop – Cough: Exercise, speech and music. Pulm Pharmacol Ther 2009; 22:143-7. [DOI: 10.1016/j.pupt.2008.12.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2008] [Accepted: 12/18/2008] [Indexed: 10/21/2022]
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Affiliation(s)
- K F Chung
- National Heart and Lung Institute, Imperial College, London, UK.
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Plant T, Aref-Adib G. Travelling to new heights: practical high altitude medicine. Br J Hosp Med (Lond) 2008; 69:348-52. [DOI: 10.12968/hmed.2008.69.6.29626] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Tracie Plant
- Birmingham University Medical School, Birmingham B15 2TT and
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Wu TY, Ding SQ, Liu JL, Yu MT, Jia JH, Chai ZC, Dai RC, Zhang SL, Li BY, Pan L, Liang BZ, Zhao JZ, Qi DT, Sun YF, Kayser B. Who should not go high: chronic disease and work at altitude during construction of the Qinghai-Tibet railroad. High Alt Med Biol 2007; 8:88-107. [PMID: 17584003 DOI: 10.1089/ham.2007.1015] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
From 2001 to 2005, a new railroad linking Beijing with Lhasa was built by more than 100,000 workers, of whom 80% traveled from their lowland habitat to altitudes up to 5000 m to work on the railroad. We report on the medical conditions of 14,050 of these altitude workers, specifically with regard to preexisting illness. All subjects were seen at low and high altitude. Average age was 29.5 +/- 7.4 (SD) yr, range 20 to 62 yr; 98.8% of the subjects were men and 1.2% were women. Overall incidence of AMS upon first-time exposure was 51%, that of HACE 0.28%, and that of HAPE 0.49%. About 1% of the subjects were hypertensive before altitude exposure. Those with blood pressure >or=160/95 were excluded from employment at altitude. Altitude exposure led to a greater increase of blood pressure in hypertensives compared to normotensives. On prealtitude screening prevalence of cardiac arrhythmias was 0.33%. Since the majority of these were rather benign and occurring in young and otherwise healthy subjects, we allowed altitude employment. Follow-up at altitude was uneventful. Subjects with coronary heart disease and diabetes were excluded from altitude employment. Obesity was a risk factor for acute mountain sickness and for reduced work performance at altitude. Overweight subjects lost more weight during their altitude stay than subjects with normal weight. Altitude exposure was a risk factor for upper gastrointestinal tract bleeding, especially in combination with alcohol, aspirin, and dexamethasone intake. Asthmatic subjects generally did better at altitude compared to low altitude, with the exception of one subject who experienced an asthma episode from pollen exposure. In conclusion, careful evaluation of preexisting chronic illness and risk factors allowed prevention of altitude deterioration of a preexisting health condition, all the while allowing subjects with some specific conditions to work and live at altitude without problems.
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Affiliation(s)
- Tian-Yi Wu
- Physiological Research Group of the Ministry of Railroad, P. R. China.
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