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Updated: Aug 14, 2026

Expired CO2 Measurement in Intubated or Spontaneously Breathing Patients from the Emergency Department
Published on: January 30, 2011
Change of carbon monoxide in plasma and tissue during acute hypoxia
Xueqin Ding1, Guiming Liu, Junke Wang
1Department of Anesthesiology and ICU, the First Affiliated Hospital, China Medical University, Shenyang 110001. xueqinding@yahoo.com
Objective:
To investigate the role of endogenous carbon monoxide (CO) in hypoxia.
Methods:
After rats were inhaled with hypoxic gases and the heme oxygenase inhibitor ZnPPIX was administered, we measured the CO levels in plasma, liver, lung and kidney. Meanwhile plasma cGMP levels were observed. Furthermore, we recorded the change of hemodynamic and blood gases.
Results:
Acute mild hypoxia (10% O2) significantly increaed CO levels in plasma as well as liver, kidney and lung, while acute severe hypoxia (5% O2) significantly decreased CO levels in plasma as well as liver, kidney and lung. In addition, the former significantly elevated cGMP levels in plasma while the latter markedly reduced cGMP levels in plasma. The hemodynamic change occurred in accordance with the changes carbon monoxide.
Conclusion:
Our results indicate, for the first time, that the endogenous carbon monoxide plays an important role in regulating the vessel tone during hypoxia.
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