The effect of N2O on the oxyhemoglobin dissociation curve is mediated by CO2.
In order to test whether the previously reported effect of N2O on the oxyhemoglobin dissociation curve (ODC) depends upon the presence of 2, 3 DPG or CO2, the blood of healthy subjects was balanced in microtonometers at 37 degrees C with gas mixtures containing N2O but CO2 depleted. Samples of the same blood were exposed to the above gases after incubation at 37 degrees C for 24 hours in order to deplete them of 2, 3 DPG. After a 10 minute tonometry, the hemoglobin saturation and the pH were measured. The pH was corrected into 7.4.P50 increased 5.7% in fresh blood and 5% in 2, 3 DPG depleted blood after samples exposure to N2O. No effect of N2O on P50 was found in samples exposed to gas without CO2. The authors conclude that the effect of N2O on the ODC is mediated by CO2.
Lanza
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V
Servizio di Anestesia, Casa di Cura Buccheri La Ferla Fatebenefratelli, Palermo.
Mercadante
S
S
Sanfilippo
A
A
D019794:2,3-Diphosphoglycerate; D002245:Carbon Dioxide / Q000378:metabolism*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004163:Diphosphoglyceric Acids / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009609:Nitrous Oxide / Q000494:pharmacology*; D010108:Oxyhemoglobins / Q000187:drug effects* / Q000378:metabolism
D004163:Diphosphoglyceric Acids; D010108:Oxyhemoglobins; D019794:2,3-Diphosphoglycerate; D002245:Carbon Dioxide; D009609:Nitrous Oxide