일산화탄소가 태아혈액의 산소평형 곡선에 미치는 영향에 관한 연구 = Studies on the Effects of Carbon Monoxide in the Oxygen Equilibrium Curve of Fetal Blood

다국어 초록 (Multilingual Abstract)

Oxygen equilibrium curve of fetal blood is a major determinant of tissue oxygen tension and thus of oxygen supply to fetal tissue. Despite the great clinical importance of this area, oxygen binding properties of fetal blood currently are known only at one point on the curve, i. e. the affinity at half saturation, P_50 and also direct measurement of carbon monoxide's effect on oxygen binding are not known for fetal blood.
The goal of this study was to synthesize the results of these measurements into clinically useful practical equations describing oxygen transport in the presence and absence of carbon monoxide in normal fetal blood.
Oxygen equilibrium curves of fetal blood samples were measured by means of thin blood film dual wave length spectrophotometry and electrode oximetry using soret wave lengths of 430-453 ㎚ under standard condition.
All measurements was made on blood whose isohemoglobin profile has been established by isoelectric focussing.
Obtained results are summarized as follows.
1. Hb_F content of cord blood was 66.2±1.35% of total Hb.
2. The oxygen equilibrium curves of fetal blood were shifted to the left with increasing CO saturation of Hb. P_50 of normal fetal blood and of blood saturated by 11.7, 19.0, 31.8, and 45.7% carbon monoxide were 23.83±0.47, 20.16±0.28, 19.34±0.63, 15.88±0.73, and 12.11±0.28㎜Hg, respectively.
3. The relationship between log P_50 and〔COHb, %〕of the fetal blood was log P_50=1.382-0.006〔COHb, %〕.
The correlation coefficient(r=-0.95) was statistically significant. The P_50 of fetal blood in the presence or absence of carbon monoxide can be obtained by the following equation.
P_50(㎜Hg)=antilog〔1.382-0.006〔COHb, %〕〕
4. Hill's constant(n) and K values of normal fetal blood were 2.55 and 3.2×10 exp (-4).
An increase in the K values and a decrease in the Hill's constant (n) were associated with the increased saturation of carbon monoxide in the fetal blood. Hill's relationship (log (S/1-S) vs. log Po_2) in the presence〔COHb, %〕and absence of carbon monoxide exhibited linear and correlation coefficient (r>0.99). were statistically significant
5. The relationships between Hill's constant (n) or log K and log〔COHb, %〕can be expressed as following equation.
n=2.693-0.65 log〔COHb, %〕
log K=1.48 log〔COHb, %〕-1.48
Both of correlation coefficient, -0.99 and 0.99, were statistically significant.
6. Oxygen equilibrium curve of fetal blood saturated partially with carbon monoxide can be obtained from the following formulas.
PO_2=〔SO_2/K (1-SO_2)〕^1/n
n=2.693-0.65 log〔COHb, %〕
K=antilog〔1.48 log〔COHb, %〕-4.18〕