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Table 1 Observational acid–base patterns

From: Determinants of blood pH in health and disease

Disorder

HCO3- (mmol/l)

pCO2 (mmHg)

SBE (mmol/I)

Metabolic acidosis

<22

= (1.5 × HCO3-) + 8

<-5

  

= 40 + SBE

 

Metabolic alkalosis

>26

= (0.7 × HCO3-) + 21

>+5

  

= 40 + (0.6 × SBE)

 

Acute respiratory acidosis

= [(pCO2 – 40)/10] + 24

>45

= 0

Chronic respiratory acidosis

= [(pCO2 – 40)/3] + 24

>45

= 0.4 × (pCO2 – 40)

Acute respiratory alkalosis

= [(40 – pCO2)/5] + 24

<35

= 0

Chronic respiratory alkalosis

= [(40 – pCO2)/2] + 24

<35

= 0.4 × (pCO2 – 40)

  1. Compiled from various sources. The changes in SBE were taken fromSchlichtig et al [7]. pCO2, partialcarbon dioxide tension; SBE, standard base excess.