Rapid Estimation of Plasma Carbon Dioxide Tension from pH and Total Carbon Dioxide Content

Abstract

PLASMA carbon dioxide tension (pCO₂), the most useful index of the respiratory component of an acid–base disorder, is frequently unavailable to the clinician. Although it can be measured directly or calculated from blood pH and plasma total carbon dioxide content, the measurement is technically difficult, and the calculation requires the use of logarithms to solve a complex expression derived from the Henderson–Hasselbalch equation: where ∝ = 0.0301 milliequiv. per liter per millimeter of mercury, and pK = 6.10.In an effort to circumvent these difficulties, Singer and Hastings¹ introduced an acid–base nomogram that has been widely used in . . .