Abstract
Hemoglobin concentration ([Hb]) is a function of total hemoglobin mass (tHb-mass) and plasma volume. [Hb] may fall by dilution due to plasma volume expansion and changes in the perioperative period may therefore correlate poorly with blood loss. A simple, reliable, repeatable way to measure plasma volume and tHb-mass would have substantial clinical utility. The “optimized carbon monoxide re-breathing method” (oCOR) meets these criteria. However, it is recommended that a minimum of 12 h (when breathing room air) is left between repeat measurements. Twenty-four subjects underwent 3 days of testing. Two oCOR tests were performed (T1 and T2), 3 h apart, with a different CO clearance method employed between tests aiming to keep the carboxyhemoglobin level below 10%. The primary aim was to ascertain whether tHb-mass testing could be safely repeated within 3 h if carboxyhemoglobin levels were actively reduced by breathing supplemental oxygen (PROCA). Secondary aims were to compare two other clearance methods; moderate exercise (PROCB), or a combination of the two (PROCC). Finally, the reliability of the oCOR method was assessed. Mean (SD) tHb-mass was 807.9 ± (189.7 g) (for T1 on day 1). PROCA lowered the carboxyhemoglobin level from the end of T1 (mean 6.64%) to the start of T2 (mean 2.95%) by a mean absolute value of 3.69%. For PROCB and PROCC the mean absolute decreases in carboxyhemoglobin were 4.00% and 4.31%, respectively. The fall in carboxyhemoglobin between T1 and T2 was greatest in PROCC; this was statistically significantly lower than that of PROCA (P = 0.0039) and PROCB (P = 0.0289). The test-retest reliability for the measurement of total hemoglobin mass was good with a mean typical error (TE) of 2.0%. The oCOR method is safe and can be repeated within 3 h when carbon monoxide is suitably cleared between tests. Using oxygen therapy alone adequately achieves this.
| Original language | English |
|---|---|
| Article number | e13829 |
| Number of pages | 13 |
| Journal | Physiological Reports |
| Volume | 6 |
| Issue number | 17 |
| DOIs | |
| Publication status | Published - Sept 2018 |
| Externally published | Yes |
Keywords
- Blood volume
- optimized carbon monoxide re-breathing
- plasma volume
- red cell volume
- total hemoglobin mass (tHb-mass)
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In: Physiological Reports, Vol. 6, No. 17, e13829, 09.2018.
Research output: Contribution to journal › Article › Research › peer-review
TY - JOUR
T1 - Replicating measurements of total hemoglobin mass (tHb-mass) within a single day
T2 - precision of measurement; feasibility and safety of using oxygen to expedite carbon monoxide clearance
AU - Plumb, James O.M.
AU - Kumar, Shriya
AU - Otto, James
AU - Schmidt, Walter
AU - Richards, Toby
AU - Montgomery, Hugh E.
AU - Grocott, Mike P.W.
N1 - Funding Information: SK received a bursary form the Royal College of Surgeons of England to undertake this study as part of her Masters of Medical Sciences degree at the University of Southampton. JP received a grant from the Association of Anaesthetists of Great Britain and Northern Ireland (AAGBI) via the National Institute of Academic Anaesthesia (NIAA) for work on hemoglobin mass measurement in the clinical setting without which this study would not have been possible. JP and MG work within the University of Southampton NIHR Respiratory Biomedical Research Unit, which received a portion of funding from the UK Department of Health Research Biomedical Research Units funding scheme. All funding was unrestricted. HM is funded in part by the Funding Information: JP has received financial support from Siemens Healthcare Limited for consumables and hardware for research into the measurement of hemoglobin mass (2015-2018). JP was given consumables from Intersurgical UK Ltd (2015-2018); has received honoraria for speaking and/or travel expenses from Siemens and Vifor Pharma and has received unrestricted grant funding from Pharmacosmos. JP is unaware of any direct or indirect conflict of interest with the contents of this paper or its related fields. SK has no conflicts of interest. JO has no conflicts of interest. WS is a managing partner of the company “Blood tec GmbH,” but he is unaware of any direct or indirect conflict of interest with the contents of this paper. TR is director of the ironclinic.com. and has received research funding from a variety of sources, including; government, charity, and industry sources for research into anemia, blood transfusion, and iron therapy, including NIHR HTA, NHMRC, Health Foundation, Gideon Richter, Vifor Pharma Ltd, and Pharmaocosmos. He has also been an invited speaker at conferences and provided consultancy to government and industry on anemia, blood transfusion, and iron therapy in the last 5 year. Please see www.ucl.ac.uk for full list of disclosures. HM consults for Google Deepmind on health technology and is on the Council of the UK Intensive Care Society but is unaware of any direct or indirect conflict of interest with the contents of this paper or its related fields. MG is vice-president of CPX International. He also serves on the medical advisor board of Sphere Medical Ltd and the board of EBPOM Community Interest Company, Medinspire Ltd and Oxygen Control Systems Ltd. He has received honoraria for speaking for and/or travel expenses from BOC Medical (Linde Group), Edwards Lifesciences and Cortex GmBH and unrestricted research support from Sphere Medical Ltd and Pharmacosmos Ltd. He leads the Fit-4-Surgery research collaboration and the Xtreme Everest oxygen research consortium, which has received unrestricted research grant funding from BOC Medical (Linde Group), Deltex Medical and Smiths Medical. MPWG was funded in part from the British Oxygen Company Chair of the Royal College of Anaesthetists awarded by the National Institute of Academic Anaesthesia. All funding was unrestricted. The funders had no role in study design, data collection, and analysis, decision to publish or the preparation of the manuscript. This work was conducted at the Southampton NIHR Biomedical Research Centre with subjects studied within the Southampton NIHR Clinical Research Facility. Funding Information: Funding Information SK received a bursary form the Royal College of Surgeons of England to undertake this study as part of her Masters of Medical Sciences degree at the University of Southampton. JP received a grant from the Association of Anaesthetists of Great Britain and Northern Ireland (AAGBI) via the National Institute of Academic Anaesthesia (NIAA) for work on hemoglobin mass measurement in the clinical setting without which this study would not have been possible. JP and MG work within the University of Southampton NIHR Respiratory Biomedical Research Unit, which received a portion of funding from the UK Department of Health Research Biomedical Research Units funding scheme. All funding was unrestricted. HM is funded in part by the NIHR University College London Hospitals Biomedical Research Centre, to whom we express our thanks. We thank the NIHR/Wellcome Clinical Research Facility for allowing patients to be tested in this facility in Southampton. We also thank Intersurgical Ltd, Berkshire, UK for providing 3-L anesthetic bags for the study. We thank Siemens Healthcare Diagnostics Inc, USA for providing blood gas syringes for the experiments. Publisher Copyright: © 2018 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.
PY - 2018/9
Y1 - 2018/9
N2 - Hemoglobin concentration ([Hb]) is a function of total hemoglobin mass (tHb-mass) and plasma volume. [Hb] may fall by dilution due to plasma volume expansion and changes in the perioperative period may therefore correlate poorly with blood loss. A simple, reliable, repeatable way to measure plasma volume and tHb-mass would have substantial clinical utility. The “optimized carbon monoxide re-breathing method” (oCOR) meets these criteria. However, it is recommended that a minimum of 12 h (when breathing room air) is left between repeat measurements. Twenty-four subjects underwent 3 days of testing. Two oCOR tests were performed (T1 and T2), 3 h apart, with a different CO clearance method employed between tests aiming to keep the carboxyhemoglobin level below 10%. The primary aim was to ascertain whether tHb-mass testing could be safely repeated within 3 h if carboxyhemoglobin levels were actively reduced by breathing supplemental oxygen (PROCA). Secondary aims were to compare two other clearance methods; moderate exercise (PROCB), or a combination of the two (PROCC). Finally, the reliability of the oCOR method was assessed. Mean (SD) tHb-mass was 807.9 ± (189.7 g) (for T1 on day 1). PROCA lowered the carboxyhemoglobin level from the end of T1 (mean 6.64%) to the start of T2 (mean 2.95%) by a mean absolute value of 3.69%. For PROCB and PROCC the mean absolute decreases in carboxyhemoglobin were 4.00% and 4.31%, respectively. The fall in carboxyhemoglobin between T1 and T2 was greatest in PROCC; this was statistically significantly lower than that of PROCA (P = 0.0039) and PROCB (P = 0.0289). The test-retest reliability for the measurement of total hemoglobin mass was good with a mean typical error (TE) of 2.0%. The oCOR method is safe and can be repeated within 3 h when carbon monoxide is suitably cleared between tests. Using oxygen therapy alone adequately achieves this.
AB - Hemoglobin concentration ([Hb]) is a function of total hemoglobin mass (tHb-mass) and plasma volume. [Hb] may fall by dilution due to plasma volume expansion and changes in the perioperative period may therefore correlate poorly with blood loss. A simple, reliable, repeatable way to measure plasma volume and tHb-mass would have substantial clinical utility. The “optimized carbon monoxide re-breathing method” (oCOR) meets these criteria. However, it is recommended that a minimum of 12 h (when breathing room air) is left between repeat measurements. Twenty-four subjects underwent 3 days of testing. Two oCOR tests were performed (T1 and T2), 3 h apart, with a different CO clearance method employed between tests aiming to keep the carboxyhemoglobin level below 10%. The primary aim was to ascertain whether tHb-mass testing could be safely repeated within 3 h if carboxyhemoglobin levels were actively reduced by breathing supplemental oxygen (PROCA). Secondary aims were to compare two other clearance methods; moderate exercise (PROCB), or a combination of the two (PROCC). Finally, the reliability of the oCOR method was assessed. Mean (SD) tHb-mass was 807.9 ± (189.7 g) (for T1 on day 1). PROCA lowered the carboxyhemoglobin level from the end of T1 (mean 6.64%) to the start of T2 (mean 2.95%) by a mean absolute value of 3.69%. For PROCB and PROCC the mean absolute decreases in carboxyhemoglobin were 4.00% and 4.31%, respectively. The fall in carboxyhemoglobin between T1 and T2 was greatest in PROCC; this was statistically significantly lower than that of PROCA (P = 0.0039) and PROCB (P = 0.0289). The test-retest reliability for the measurement of total hemoglobin mass was good with a mean typical error (TE) of 2.0%. The oCOR method is safe and can be repeated within 3 h when carbon monoxide is suitably cleared between tests. Using oxygen therapy alone adequately achieves this.
KW - Blood volume
KW - optimized carbon monoxide re-breathing
KW - plasma volume
KW - red cell volume
KW - total hemoglobin mass (tHb-mass)
UR - http://www.scopus.com/inward/record.url?scp=85053340406&partnerID=8YFLogxK
U2 - 10.14814/phy2.13829
DO - 10.14814/phy2.13829
M3 - Article
C2 - 30203465
AN - SCOPUS:85053340406
SN - 2051-817X
VL - 6
JO - Physiological Reports
JF - Physiological Reports
IS - 17
M1 - e13829
ER -