### Abstract

A Dl_{O2 } 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 O_{2} and CO_{2} 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 Dl_{O2 } 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 Dl_{O2 } estimates based on linear dissociation curves exceeded integrated Dl_{O2 } estimates by 14, 31, and 55 percent when the Pi_{O2 } was 80, 100, and 148 Torr, respectively. We conclude that the linear approximation is accurate when Pi_{O2 } is less than 100 Torr but that comparisons of Dl_{O2 } estimates at different levels of inspired oxygen must allow for the difference in curvature of the oxygen dissociation curve as a function of Pi_{O2 }.

Original language | English (US) |
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Pages (from-to) | 279-288 |

Number of pages | 10 |

Journal | Respiration Physiology |

Volume | 73 |

Issue number | 3 |

DOIs | |

State | Published - Sep 1988 |

Externally published | Yes |

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### Keywords

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

### ASJC Scopus subject areas

- Physiology
- Pulmonary and Respiratory Medicine

### Cite this

_{O2 }with nonlinear dissociation curves and Va/Q̇ inequality.

*Respiration Physiology*,

*73*(3), 279-288. https://doi.org/10.1016/0034-5687(88)90050-3