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An overlooked aspect on metabolic acidosis at birth: blood gas analyzers calculate base deficit differently.

Mokarami, Parisa LU ; Wiberg, Nana LU and Olofsson, Per LU (2012) In Acta Obstetricia et Gynecologica Scandinavica 91(5). p.574-579
Abstract
Background: Metabolic acidosis (MA) at birth is commonly defined as umbilical cord arterial pH <7.0 plus base deficit (BD) ≥12.0 mmol/L. BD is not a measured entity but calculated from pH and pCO(2) values, with the hemoglobin (Hb) concentration included in the calculation algorithm as a fixed or actual value. Various blood gas analyzers use different algorithms, indicating variations in the MA diagnosis. Objective. To calculate the prevalence of MA in blood and extracellular fluid (ecf) with algorithms from three blood gas analyzer brands relative to the Clinical and Laboratory Standards Institute (CLSI) algorithm.



Design: Comparative study. Setting. University hospital. Sample. Arterial cord blood from 15354... (More)
Background: Metabolic acidosis (MA) at birth is commonly defined as umbilical cord arterial pH <7.0 plus base deficit (BD) ≥12.0 mmol/L. BD is not a measured entity but calculated from pH and pCO(2) values, with the hemoglobin (Hb) concentration included in the calculation algorithm as a fixed or actual value. Various blood gas analyzers use different algorithms, indicating variations in the MA diagnosis. Objective. To calculate the prevalence of MA in blood and extracellular fluid (ecf) with algorithms from three blood gas analyzer brands relative to the Clinical and Laboratory Standards Institute (CLSI) algorithm.



Design: Comparative study. Setting. University hospital. Sample. Arterial cord blood from 15354 newborns. Main outcome measure. Prevalence of MA. Methods. Blood was analyzed in a Radiometer ABL 735 analyzer. BD was calculated post hoc with algorithms from CLSI and Corning and Roche blood gas analyzers, and with actual and fixed (9.3 mmol/L) Hb values.



Results: The prevalence of BD ≥12.0 mmol/L in blood was with the CLSI algorithm 1.97%, Radiometer 5.18%, Corning 3.84%, and Roche 3.29% (CLSI vs other; McNemar test, P <0.000001). Similarly, MA prevalences were 0.58%, 0.66%, 0.64% and 0.64% (P≤0.02). BD ≥12.0 and MA rates were lower in ecf than in blood (P≤0.002). Algorithms with actual or fixed Hb concentration made no differences in MA rates (P≥0.1). Conclusion. The neonatal metabolic acidosis rate varied significantly with blood gas analyzer brand and fetal fluid compartment for calculation of BD. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Acta Obstetricia et Gynecologica Scandinavica
volume
91
issue
5
pages
574 - 579
publisher
Wiley-Blackwell
external identifiers
  • wos:000303001500009
  • pmid:22268583
  • scopus:84860243670
ISSN
1600-0412
DOI
10.1111/j.1600-0412.2012.01364.x
language
English
LU publication?
yes
id
3a7504bc-a6c4-463b-ba72-58232a0a1b09 (old id 2336068)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/22268583?dopt=Abstract
date added to LUP
2012-02-01 22:47:59
date last changed
2017-01-01 07:53:22
@article{3a7504bc-a6c4-463b-ba72-58232a0a1b09,
  abstract     = {Background: Metabolic acidosis (MA) at birth is commonly defined as umbilical cord arterial pH &lt;7.0 plus base deficit (BD) ≥12.0 mmol/L. BD is not a measured entity but calculated from pH and pCO(2) values, with the hemoglobin (Hb) concentration included in the calculation algorithm as a fixed or actual value. Various blood gas analyzers use different algorithms, indicating variations in the MA diagnosis. Objective. To calculate the prevalence of MA in blood and extracellular fluid (ecf) with algorithms from three blood gas analyzer brands relative to the Clinical and Laboratory Standards Institute (CLSI) algorithm. <br/><br>
<br/><br>
Design: Comparative study. Setting. University hospital. Sample. Arterial cord blood from 15354 newborns. Main outcome measure. Prevalence of MA. Methods. Blood was analyzed in a Radiometer ABL 735 analyzer. BD was calculated post hoc with algorithms from CLSI and Corning and Roche blood gas analyzers, and with actual and fixed (9.3 mmol/L) Hb values. <br/><br>
<br/><br>
Results: The prevalence of BD ≥12.0 mmol/L in blood was with the CLSI algorithm 1.97%, Radiometer 5.18%, Corning 3.84%, and Roche 3.29% (CLSI vs other; McNemar test, P &lt;0.000001). Similarly, MA prevalences were 0.58%, 0.66%, 0.64% and 0.64% (P≤0.02). BD ≥12.0 and MA rates were lower in ecf than in blood (P≤0.002). Algorithms with actual or fixed Hb concentration made no differences in MA rates (P≥0.1). Conclusion. The neonatal metabolic acidosis rate varied significantly with blood gas analyzer brand and fetal fluid compartment for calculation of BD.},
  author       = {Mokarami, Parisa and Wiberg, Nana and Olofsson, Per},
  issn         = {1600-0412},
  language     = {eng},
  number       = {5},
  pages        = {574--579},
  publisher    = {Wiley-Blackwell},
  series       = {Acta Obstetricia et Gynecologica Scandinavica},
  title        = {An overlooked aspect on metabolic acidosis at birth: blood gas analyzers calculate base deficit differently.},
  url          = {http://dx.doi.org/10.1111/j.1600-0412.2012.01364.x},
  volume       = {91},
  year         = {2012},
}