Estimating steady-state DlO2 with nonlinear dissociation curves and Va/Q̇ inequality

Steven C. Hempleman, Andrew T. Gray

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


A DlO2 estimate which accounts for the nonlinearity of the oxygen dissociation curve using the Kelman blood gas routines is presented here. The simultaneous differential equations that describe O2 and CO2 diffusion between alveolar gas and pulmonary capillary blood in lung compartments with different V̇a/Q̇ ratios were solved numerically with a Runge-Kutta algorithm. These integrated estimates were compared to DlO2 estimates the assume the oxygen dissociation curve is linear. In 140 gas exchange data sets from 18 healthy male subjects previously collected at rest and during exercise it was found that DlO2 estimates based on linear dissociation curves exceeded integrated DlO2 estimates by 14, 31, and 55 percent when the PiO2 was 80, 100, and 148 Torr, respectively. We conclude that the linear approximation is accurate when PiO2 is less than 100 Torr but that comparisons of DlO2 estimates at different levels of inspired oxygen must allow for the difference in curvature of the oxygen dissociation curve as a function of PiO2 .

Original languageEnglish (US)
Pages (from-to)279-288
Number of pages10
JournalRespiration Physiology
Issue number3
StatePublished - Sep 1988


  • Bohr integration
  • Hypoxia
  • Inert gases
  • Normoxia
  • Oxygen diffusing capacity

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine


Dive into the research topics of 'Estimating steady-state DlO2 with nonlinear dissociation curves and Va/Q̇ inequality'. Together they form a unique fingerprint.

Cite this