Endogenous carbon monoxide production and blood loss at delivery.

Abstract

Rate of CO production in 14 healthy controls was compared with the rate in 33 pregnant women during the last month of pregnancy and during the 1st 24 hours after delivery. Neither hemoglobin (Hb) nor carboxyhemoglobin (CHb) changed appreciably up to 24 horus after delivery (10.5 immediately postpartum-11.1 gm/100 ml 24 hours postpartum for Hb and .4-.38% for CHb). Mean CO production seemed to be almost the same before and after delivery even when the calculations were based on the individual differences. Mean CO production was somewhat lower in the control nonpregnant group than in the pregnant group whereas the rate of CO production/gm of total Hb was approximately the same in both groups. Calculated from the individual differences the mean CO production/gm of total Hb before delivery and up to 24 horus after delivery showed rather small (.98-1.22 mal/h/gm) and statistically insignificant changes. The total amount of Hb in the 10 subjects in whom the external blood loss at delivery was measured was on the average 106 gm less 3-5 days after delivery than before delivery. At delivery and during the 1st 4 postpartum days the estimated average external blood loss was 64.6 gm Hb. The difference was 42.2+ or -14.6 gm Hb (P < .01). An investigation of the specificity of the methods for CO analysis revealed that the palladium-molybdenum test tube method for analysis of CO in gas was insensitive to nitrous oxide trichorethylene and chloroform. The hopcalite meter was sensitive to nitrous oxide chloroform and probably to trichlorethylene and the infra-red meter to nitrous oxide.