Half-life of blood carboxyhemoglobin after short-term and long-term exposure to carbon monoxide

J Trauma. 2000 Jul;49(1):126-31. doi: 10.1097/00005373-200007000-00019.

Abstract

Background: In models of smoke inhalation injury and carbon monoxide poisoning blood carboxy-hemoglobin (COHb) levels decrease faster than predicted by the generally recognized half-life of COHb. We studied the effects of duration of exposure to carbon monoxide (CO) on the subsequent CO elimination.

Methods: Each of four sheep were insufflated with CO gas mixtures either for a few minutes (short-term exposure) or for several hours (long-term exposure), then ventilated with air for 3 hours. Serial COHb concentrations were analyzed by using a two-compartment, single central outlet mathematical model.

Results: Short-term exposures exhibited biphasic decreases of COHb concentration compatible with a two-compartment model; an initial rapid decrease (half-life 5.7 +/- 1.4 minutes) was followed by a slower phase (103 +/- 20.5 minutes). Long-term exposures exhibited almost monophasic decreases, which were nevertheless compatible with the model (half-life, 21.5 +/- 2.1 and 118 +/- 11.2 minutes).

Conclusion: This study demonstrated different patterns of CO elimination curve, which suggests distribution of CO to two compartments having different rates of equilibration.

MeSH terms

  • Administration, Inhalation
  • Animals
  • Carbon Monoxide / administration & dosage
  • Carbon Monoxide / pharmacokinetics*
  • Carboxyhemoglobin / metabolism*
  • Disease Models, Animal
  • Female
  • Half-Life
  • Hemodynamics
  • Respiratory Function Tests
  • Sheep
  • Smoke Inhalation Injury / physiopathology*
  • Time Factors

Substances

  • Carbon Monoxide
  • Carboxyhemoglobin