Effect of altitude on spirometric parameters and the performance of peak flow meters.

Pollard, Andrew J.; Mason, Nicholas; Barry, Peter; Pollard, R.C.; Collier, David; Fraser, Robert S.; Miller, Martin; Milledge, J. S.

doi:10.1136/thx.51.2.175

Cited by 47 publications

(42 citation statements)

References 14 publications

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“…1). The changes in OPEF are in keeping with previous reports [9,10]. Linear modelling, used to take account of intersubject variation, demonstrated a rise in NPIF of 0.086¡0.03 L?s -1 per kilometre of 0 1 198 378 624 99 2 198 264 492 99 3 192 510 534 98 4 372 720 720 98 5 228 426 522 99 7 204 534 780 98 8 198 348 540 98 5000 1 252 336 732 84 2 228 552 672 86 3 240 600 618 87 4 426 690 870 84 5 270 612 642 85 7 252 612 840 84 8 318 564 690 82 8000 1 ND ND ND ND 2 240 414 690 80 3 198 780 726 70 4 378 882 882 67 5 252 684 714 69 7 258 636 912 57 8 252 504 744 66 NPIF: nasal peak inspiratory flow; OPIF: oral peak inspiratory flow; OPEF: oral peak expiratory flow; ND: not determined.…”

Section: Resultssupporting

confidence: 77%

Nasal peak inspiratory flow at altitude

Barry¹,

Mason²,

Richalet³

2002

Eur Respir J

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Nasal peak inspiratory flow at altitude. P.W. Barry, N.P. Mason, J-P. Richalet. #ERS Journals Ltd 2002. ABSTRACT: The present study investigated whether there are changes in nasal peak inspiratory flow (NPIF) during hypobaric hypoxia under controlled environmental conditions.During operation Everest III (COMEX 997), eight subjects ascended to a simulated altitude of 8,848 m in a hypobaric chamber. NPIF was recorded at simulated altitudes of 0 m, 5,000 m and 8,000 m. Oral peak inspiratory and expiratory flow (OPIF, OPEF) were also measured. Ambient air temperature and humidity were controlled.NPIF increased by a mean¡SD of 16¡12% from sea level to 8,000 m, whereas OPIF increased by 47 ¡ 14%. NPIF rose by 0.085 ¡ 0.03 L?s -1 per kilometre of ascent (pv0.05), significantly less than the rise in OPIF and OPEF of 0.35 ¡ 0.10 and 0.33 ¡ 0.04 L?s -1 per kilometre (pv0.0005). Nasal peak inspiratory flow rises with ascent to altitude. The rise in nasal peak inspiratory flow with altitude was far less than oral peak inspiratory flow and less than the predicted rise according to changes in air density. This suggests flow limitation at the nose, and occurs under controlled environmental conditions, refuting the hypothesis that nasal blockage at altitude is due to the inhalation of cold, dry air. Further work is needed to determine if nasal blockage limits activity at altitude.

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Section: Resultssupporting

confidence: 77%

Nasal peak inspiratory flow at altitude

Barry¹,

Mason²,

Richalet³

2002

Eur Respir J

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“…Sa,O 2 fell to a mean of 86% at 5,000 m and 68% at 8,000 m. At 8,000 m PEF increased by a mean of 27%, FVC fell by 6.8% and FEV1 was unchanged. These changes in spirometry are in keeping with previous reports [14]. Citric acid challenge did not produce a significant fall in FEV1 in comparison with prechallenge values.…”

Section: Citric Acid Cough Challengesupporting

confidence: 92%

Cough frequency and cough receptor sensitivity to citric acid challenge during a simulated ascent to extreme altitude

Mason¹,

Barry²,

Despiau³

et al. 1999

Eur Respir J

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Cough frequency and cough receptor sensitivity to citric acid challenge during a simulated ascent to extreme altitude. N.P. Mason, P.W. Barry, G. Despiau, B. Gardette, J-P. Richalet. #ERS Journals Ltd 1999. ABSTRACT: The aim of this study was to determine the frequency of cough and the citric acid cough threshold during hypobaric hypoxia under controlled environmental conditions.Subjects were studied during Operation Everest 3. Eight subjects ascended to a simulated altitude of 8,848 m over 31 days in a hypobaric chamber. Frequency of nocturnal cough was measured using voice-activated tape recorders, and cough threshold by inhalation of increasing concentrations of citric acid aerosol. Spirometry was performed before and after each test. Subjects recorded symptoms of acute mountain sickness and arterial oxygen saturation daily. Air temperature and humidity were controlled during the operation.Cough frequency increased with increasing altitude, from a median of 0 coughs (range 0±4) at sea level to 15 coughs (range 3±32) at a simulated altitude of 8,000 m. Cough threshold was unchanged on arrival at 5,000 m compared to sea level (geometric mean difference (GMD) 1.0, 95% confidence intervals (CI) 0.5±2.1, p=0.5), but fell on arrival at 8,000 m compared to sea level (GMD 3.3, 95% CI 1.1±10.3, p=0.043). There was no relationship between cough threshold and symptoms of acute mountain sickness, oxygen saturation or forced expiratory volume in one second. Temperature and humidity in the chamber were controlled between 18±248C and 30±60%, respectively.These results confirm an increase in cough frequency and cough receptor sensitivity associated with hypobaric hypoxia, and refute the hypothesis that high altitude cough is due to the inhalation of cold, dry air. The small sample size makes further conclusions difficult, and the cause of altitude-related cough remains unclear. Eur Respir J 1999; 13: 508±513. Numerous anecdotal reports exist of paroxysmal cough in climbers and travellers to high altitude [1±3] which may be severe enough to cause rib fractures [2,3]. The cause of this cough is not known, but has been attributed to the inspiration of cold, dry air, acute mountain sickness (AMS), high altitude pulmonary oedema (HAPO), bronchoconstriction or respiratory tract infection [4,5].In the first systematic study of cough at high altitude [6], an increase in cough frequency and cough receptor sensitivity was reported in a group of subjects ascending to Mount Everest Base Camp in Nepal at an altitude of 5,300 m. However, because of the nature of the study, subjects at Base Camp were unavoidably exposed to cold, dry air, which has been shown to cause cough [7]. The aim of this study was therefore to measure cough frequency and cough receptor sensitivity in a group of subjects making a simulated ascent of Mount Everest (8,848 m) in a hypobaric chamber in which the temperature and humidity were controlled within normal sea level limits, and also to study the effects of extreme hypobaric hypoxia on cough. Methods SubjectsEigh...

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“…Similarly, the reduction in FVC on day 1 at 5,300 m [11] was twice as high as that on day 3 [35]. Two studies that report predicted values [12], or data that permit calculation of predicted values [7], and also show a reduction in FVC of 8 and 7% report vital capacities of 87-96% pred.…”

Section: Lung Volumesmentioning

confidence: 95%

No evidence for interstitial lung oedema by extensive pulmonary function testing at 4,559 m

Dehnert¹,

Luks²,

Schendler

et al. 2009

European Respiratory Journal

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The aim of the present study was to better understand previously reported changes in lung function at high altitude.Comprehensive pulmonary function testing utilising body plethysmography and assessment of changes in closing volume were carried out at sea level and repeatedly over 2 days at high altitude (4,559 m) in 34 mountaineers.In subjects without high-altitude pulmonary oedema (HAPE), there was no significant difference in total lung capacity, forced vital capacity, closing volume and lung compliance between low and high altitude, whereas lung diffusing capacity for carbon monoxide increased at high altitude. Bronchoconstriction at high altitude could be excluded as the cause of changes in closing volume because there was no difference in airway resistance and bronchodilator responsiveness to salbutamol. There were no significant differences in these parameters between mountaineers with and without acute mountain sickness. Mild alveolar oedema on radiographs in HAPE was associated only with minor decreases in forced vital capacity, diffusing capacity and lung compliance and minor increases in closing volume.Comprehensive lung function testing provided no evidence of interstitial pulmonary oedema in mountaineers without HAPE during the first 2 days at 4,559 m. Data obtained in mountaineers with early mild HAPE suggest that these methods may not be sensitive enough for the detection of interstitial pulmonary fluid accumulation.

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Effect of altitude on spirometric parameters and the performance of peak flow meters.

Cited by 47 publications

References 14 publications

Nasal peak inspiratory flow at altitude

Nasal peak inspiratory flow at altitude

Cough frequency and cough receptor sensitivity to citric acid challenge during a simulated ascent to extreme altitude

No evidence for interstitial lung oedema by extensive pulmonary function testing at 4,559 m

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