The acid-base effects of free water removal from and addition to oxygenated and deoxygenated whole blood: An in vitro model of contraction alkalosis and dilutional acidosis

Katrina Hopper, Steve C. Haskins

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2 Scopus citations


This study was conducted to describe the acid-base effects of hydration and dehydration of oxygenated and deoxygenated whole blood. Whole blood samples from goats were equilibrated in a tonometer to a partial pressure of carbon dioxide of 40 mm Hg and oxygen (PO2) of 100 mm Hg or 30 mm Hg. Contraction alkalosis was achieved by evaporating blood samples to 80% of the original volume. Dilutional acidosis was achieved by increasing the blood sample volume by 20% by addition of sterile water. Acid-base, electrolyte, hemoglobin, lactate, albumin, and phosphorus concentrations were measured at baseline and after dehydration or hydration. A 20% dehydration of whole blood caused a 22% increase in sodium concentration and a significant increase in base excess of +3 mEq/L (P < 0.01); bicarbonate concentration increased only 7% to 9%. A concurrent increase was found in phosphorus, albumin, hemoglobin, and lactate concentrations. A 20% dilution of whole blood caused a 21% decrease in sodium concentration and a significant decrease in base excess of -5 mEq/L (P < 0.01) with an 11% to 15% decrease in bicarbonate concentration. A concurrent decrease was found in phosphorus, albumin, and hemoglobin concentrations. No significant difference was observed between the acid-base effects on oxygenated versus deoxygenated blood in any experiment. Dilutional acidosis and contraction alkalosis of whole blood are complex acid-base disorders resulting from direct changes in bicarbonate concentration in combination with changes in the concentration of weak plasma acids and buffering reactions. Therefore, bicarbonate concentration does not change to the same degree as the magnitude of contraction or dilution.

Original languageEnglish (US)
Pages (from-to)29-37
Number of pages9
JournalTranslational Research
Issue number1
StatePublished - Jan 2011



  • ABE
  • actual base excess
  • AG
  • anion gap
  • D100
  • D30
  • dehydration of deoxygenated whole blood trial
  • dehydration of oxygenated whole blood trial
  • hydration of deoxygenated whole blood trial
  • hydration of oxygenated whole blood trial
  • pH adjusted to a PCO of 40 mm Hg at the predetermined ABE
  • pHadj
  • SID
  • SIDapp
  • SIDeff
  • SIG
  • standardized bicarbonate for a PCO of 40mm Hg at the predetermined pH
  • stHCO
  • strong ion difference
  • strong ion difference apparent
  • strong ion difference effective
  • strong ion gap
  • W100
  • W30

ASJC Scopus subject areas

  • Medicine(all)
  • Biochemistry, medical
  • Public Health, Environmental and Occupational Health

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