Medical & Biological Engineering & Computing

, Volume 53, Issue 8, pp 699–712 | Cite as

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

  • A. GardeEmail author
  • B. F. Giraldo
  • R. Jané
  • T. D. Latshang
  • A. J. Turk
  • T. Hess
  • M. M. Bosch
  • D. Barthelmes
  • T. M. Merz
  • J. Pichler Hefti
  • O. D. Schoch
  • K. E. Bloch
Original Article


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


High-altitude periodic breathing Cardiorespiratory characterization Time-varying spectral analysis Acclimatization Hypoxia 



This work was supported by an international cooperation Grant of the Swiss National Science Foundation (SNSF), a mobility grant of the CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) and by the Ministerio de Economía y Competitividad from Spanish Government under Grant TEC2010-21703-C03-01, and by Grants from the Lung Ligue of Zurich, Switzerland.


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Copyright information

© International Federation for Medical and Biological Engineering 2015

Authors and Affiliations

  • A. Garde
    • 1
    Email author
  • B. F. Giraldo
    • 1
  • R. Jané
    • 1
  • T. D. Latshang
    • 2
  • A. J. Turk
    • 3
  • T. Hess
    • 4
  • M. M. Bosch
    • 5
  • D. Barthelmes
    • 5
  • T. M. Merz
    • 6
  • J. Pichler Hefti
    • 7
  • O. D. Schoch
    • 8
  • K. E. Bloch
    • 2
  1. 1.Biomedical Signal Processing and Interpretation (BIOSPIN) Group, Department of ESAII, Institut de Bioenginyeria de Catalunya (IBEC) and CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN)Universitat Politècnica de Catalunya (UPC)BarcelonaSpain
  2. 2.Pulmonary DivisionUniversity Hospital of ZurichZurichSwitzerland
  3. 3.High Altitude Clinic WaldWaldSwitzerland
  4. 4.Pulmonary DivisionCantonal Hospital WinterthurWinterthurSwitzerland
  5. 5.Department of OphthalmologyUniversity Hospital ZurichZurichSwitzerland
  6. 6.Intensive Care UnitUniversity Hospital of BerneBerneSwitzerland
  7. 7.Pulmonary DivisionUniversity Hospital of BerneBerneSwitzerland
  8. 8.Pulmonary DivisionCantonal Hospital St. GallenSt. GallenSwitzerland

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