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High altitude arterialised capillary earlobe blood gas measurement using the Abbott i-STAT
  1. Christopher T Lewis1,
  2. W L Malein2,
  3. I Chesner3 and
  4. S Clarke4
  5. on behalf of the Birmingham Medical Research Expeditionary Society (BMRES)
  1. 1 Academic Foundation Programme, NHS Highland, Inverness, UK
  2. 2 School of Anaesthesia, NHS Tayside, Dundee, UK
  3. 3 Medical School, University of Birmingham, Birmingham, UK
  4. 4 Department of Anaesthetics, Royal Blackburn Hospital, Blackburn, UK
  1. Correspondence to Dr Christopher T Lewis, Academic Foundation Programme, NHS Highland, Scotland IV2 3UJ, UK; christopher.lewis11{at}


Introduction Measurement of physiological parameters in extreme environments is essential to advancing knowledge, prophylaxis and treatment of altitude sickness. Point-of-care testing facilitates investigation in non-specialist and remote settings, as well as becoming increasingly popular at the bedside for real-time results in the clinical environment. Arterialised capillary earlobe blood gases are recommended as a valid alternative to arterial sampling in research. This study aimed to test the feasibility of obtaining and analysing daily earlobe samples at high altitude.

Methods From 17 to 24 January 2016, 24 participants on a research expedition to Ecuador underwent daily earlobe blood gas measurements including pH, partial pressure of oxygen and partial pressure of carbon dioxide to 5043 m. Samples were analysed using an Abbott i-STAT blood gas analyser and G3+ cartridges.

Results Daily measurements were successfully obtained and analysed at the point of care in 23/24 participants and were well tolerated with no adverse events. 12% (27/220) cartridges failed and required repeat sampling.

Conclusions Daily earlobe blood gas analysis using the Abbott i-STAT is feasible in a protected environment at high altitude. Participants and equipment should be kept warm before and during testing. Spare cartridges should be available. This methodology may be useful for both research and therapeutic measurements in remote, rural and wilderness medicine.

  • altitude medicine
  • respiratory physiology
  • physiology
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  • Contributors All authors contributed to the study design, data collection, manuscript preparation, revision and approval of the final manuscript and agreed to be accountable for the integrity of this work.

  • Funding This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.

  • Disclaimer The authors have no past or current commercial interest in Abbott Healthcare Pvt and received no commerical grant or donated equipment. All equipment used in this study was purchased by the BMRES using charitable funding from The Jabbs Foundation.

  • Competing interests None declared.

  • Patient consent Not required.

  • Ethics approval Ethical approval for this study was granted by the Chichester University Research Ethics Committee.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Collaborators Ashdown KM, Bradwell AR, Bradwell SB, Cadigan P, Campbell CA, Clarke A, Delamere J, Edsell ME, Imray CH, Johnson BG, Ladha C, Letchford A, Lock HE, Lucas SJ, MacLennan I, Myers SD, Newman C, Rue CA, Simmons J, Talks BJ, Thomas O, Wright AD

  • Correction notice Since this paper was published the author name I Chesner has been updated so just the first initial is listed and Figure 1 has been replaced to a version with higher resolution.

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