The Henderson-Hasselbalch equation has always occupied a central place
in the description of the acid-base status of the blood. An equation
of similar importance is the equation for the CO, equilibration curve
of blood in vitro. It is proposed to name this the Van Slyke equation:
a - 24.4 = -(2.3 x b + 7.7) x (c - 7.40) + d/(1 - 0.023 x b), where a
= bicarbonate concentration in plasma/(mmol/l), b = hemoglobin concen
tration in blood/(mmol/l), c = pH of plasma at 37-degrees-C, d = base
excess concentration in blood/(mmol/l). These two equations provide an
arithmetic algorithm for calculation of the various acid-base variabl
es of the blood after measuring the pH, the pCO2, and the hemoglobin c
oncentration