Experimental Determination of the Apparent Value for the First Dissociation Constant (<scp>pK</scp> 1 ′) of the Plasma Carbonic Acid – Bicarbonate Buffer System in 115 Trained Standardbreds
Introduction Calculating the total plasma concentration of carbon dioxide ( ctCO 2 ) from the results of blood gas and pH analysis assumes that the value for pK 1 ′ is constant and approximates 6.095. The objective of this study was to verify both assumptions in equine plasma. Methods Duplicate jugu...
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crwiley:10.1111/evj.12267_62 2023-12-03T10:21:02+01:00 Experimental Determination of the Apparent Value for the First Dissociation Constant (<scp>pK</scp> 1 ′) of the Plasma Carbonic Acid – Bicarbonate Buffer System in 115 Trained Standardbreds Constable, P Tinkler, S Demaree, A Couetil, L 2014 http://dx.doi.org/10.1111/evj.12267_62 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fevj.12267_62 http://onlinelibrary.wiley.com/wol1/doi/10.1111/evj.12267_62/fullpdf en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Equine Veterinary Journal volume 46, issue S46, page 21-21 ISSN 0425-1644 2042-3306 General Medicine journal-article 2014 crwiley https://doi.org/10.1111/evj.12267_62 2023-11-09T13:22:00Z Introduction Calculating the total plasma concentration of carbon dioxide ( ctCO 2 ) from the results of blood gas and pH analysis assumes that the value for pK 1 ′ is constant and approximates 6.095. The objective of this study was to verify both assumptions in equine plasma. Methods Duplicate jugular blood samples were collected pre‐race from 115 trained Standardbreds into 3 mL partially evacuated plastic tubes containing lithium heparin. Blood pH ( pHb ) and partial pressure of CO 2 ( pCO 2 ) were measured in one tube using a blood gas and pH analyser (Radiometer ABL ‐700). The second tube was anaerobically centrifuged and ctCO 2 was measured (Beckman EL ‐ ISE analyser). Plasma pK 1 ′ was calculated for each horse using the Henderson‐Hasselbalch equation, measured values for pHb , pCO 2 , and plasma ctCO 2 , and the value for the solubility of CO 2 in plasma at 37C ( S = 0.0307 {mmol/ L }/mmHg) whereby: pK 1 ′ = ( pHb + 0.01)–log10({ ctCO 2 ‐ S × pCO 2 }/{ S × pCO 2 }), with the term ( pHb + 0.01) representing the pH in plasma. The calculated value for pK 1 ′ was standardized to pHb = 7.40 using the Severinghaus equation such that d pK 1 ′/ dpH = −0.044. Non‐parametric statistical procedures were used to determine the median value and 95% confidence interval ( CI ) for pK 1 ′. Results The median value for pK 1 ′ at pHb = 7.40 was 6.097, and the 95% CI for pK 1 ′ was 6.063–6.123. Conclusions The 95% CI for pK 1 ′ in equine plasma from trained Standardbreds is narrow and includes the assumed fixed value of 6.095. Our findings support the use of blood gas and pH analysis to calculate plasma ctCO 2 in order to detect the pre‐race administration of alkalinizing agents in horses. Ethical Animal Research The study was approved by the Institutional Animal Care and Use Committee at Purdue University. Sources of funding: Supported, in part, by a grant from the Indiana Horse Racing Commission. Competing interests: none. Article in Journal/Newspaper Carbonic acid Wiley Online Library (via Crossref) Equine Veterinary Journal 46 21 21 |
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General Medicine Constable, P Tinkler, S Demaree, A Couetil, L Experimental Determination of the Apparent Value for the First Dissociation Constant (<scp>pK</scp> 1 ′) of the Plasma Carbonic Acid – Bicarbonate Buffer System in 115 Trained Standardbreds |
topic_facet |
General Medicine |
description |
Introduction Calculating the total plasma concentration of carbon dioxide ( ctCO 2 ) from the results of blood gas and pH analysis assumes that the value for pK 1 ′ is constant and approximates 6.095. The objective of this study was to verify both assumptions in equine plasma. Methods Duplicate jugular blood samples were collected pre‐race from 115 trained Standardbreds into 3 mL partially evacuated plastic tubes containing lithium heparin. Blood pH ( pHb ) and partial pressure of CO 2 ( pCO 2 ) were measured in one tube using a blood gas and pH analyser (Radiometer ABL ‐700). The second tube was anaerobically centrifuged and ctCO 2 was measured (Beckman EL ‐ ISE analyser). Plasma pK 1 ′ was calculated for each horse using the Henderson‐Hasselbalch equation, measured values for pHb , pCO 2 , and plasma ctCO 2 , and the value for the solubility of CO 2 in plasma at 37C ( S = 0.0307 {mmol/ L }/mmHg) whereby: pK 1 ′ = ( pHb + 0.01)–log10({ ctCO 2 ‐ S × pCO 2 }/{ S × pCO 2 }), with the term ( pHb + 0.01) representing the pH in plasma. The calculated value for pK 1 ′ was standardized to pHb = 7.40 using the Severinghaus equation such that d pK 1 ′/ dpH = −0.044. Non‐parametric statistical procedures were used to determine the median value and 95% confidence interval ( CI ) for pK 1 ′. Results The median value for pK 1 ′ at pHb = 7.40 was 6.097, and the 95% CI for pK 1 ′ was 6.063–6.123. Conclusions The 95% CI for pK 1 ′ in equine plasma from trained Standardbreds is narrow and includes the assumed fixed value of 6.095. Our findings support the use of blood gas and pH analysis to calculate plasma ctCO 2 in order to detect the pre‐race administration of alkalinizing agents in horses. Ethical Animal Research The study was approved by the Institutional Animal Care and Use Committee at Purdue University. Sources of funding: Supported, in part, by a grant from the Indiana Horse Racing Commission. Competing interests: none. |
format |
Article in Journal/Newspaper |
author |
Constable, P Tinkler, S Demaree, A Couetil, L |
author_facet |
Constable, P Tinkler, S Demaree, A Couetil, L |
author_sort |
Constable, P |
title |
Experimental Determination of the Apparent Value for the First Dissociation Constant (<scp>pK</scp> 1 ′) of the Plasma Carbonic Acid – Bicarbonate Buffer System in 115 Trained Standardbreds |
title_short |
Experimental Determination of the Apparent Value for the First Dissociation Constant (<scp>pK</scp> 1 ′) of the Plasma Carbonic Acid – Bicarbonate Buffer System in 115 Trained Standardbreds |
title_full |
Experimental Determination of the Apparent Value for the First Dissociation Constant (<scp>pK</scp> 1 ′) of the Plasma Carbonic Acid – Bicarbonate Buffer System in 115 Trained Standardbreds |
title_fullStr |
Experimental Determination of the Apparent Value for the First Dissociation Constant (<scp>pK</scp> 1 ′) of the Plasma Carbonic Acid – Bicarbonate Buffer System in 115 Trained Standardbreds |
title_full_unstemmed |
Experimental Determination of the Apparent Value for the First Dissociation Constant (<scp>pK</scp> 1 ′) of the Plasma Carbonic Acid – Bicarbonate Buffer System in 115 Trained Standardbreds |
title_sort |
experimental determination of the apparent value for the first dissociation constant (<scp>pk</scp> 1 ′) of the plasma carbonic acid – bicarbonate buffer system in 115 trained standardbreds |
publisher |
Wiley |
publishDate |
2014 |
url |
http://dx.doi.org/10.1111/evj.12267_62 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fevj.12267_62 http://onlinelibrary.wiley.com/wol1/doi/10.1111/evj.12267_62/fullpdf |
genre |
Carbonic acid |
genre_facet |
Carbonic acid |
op_source |
Equine Veterinary Journal volume 46, issue S46, page 21-21 ISSN 0425-1644 2042-3306 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/evj.12267_62 |
container_title |
Equine Veterinary Journal |
container_volume |
46 |
container_start_page |
21 |
op_container_end_page |
21 |
_version_ |
1784268595512999936 |