Hb-O2 Dissociation Curve Research Articles

CORRELATION BETWEEN MATERNAL AND FOETAL Po2 AND Pco2 DURING CAESAREAN SECTION

SUMMARY Fifteen cases of elective Caesarean section at term were studied under general anaesthesia. Maternal carbon dioxide tensions were controlled by adjusting the minute ventilation volume; Paco2 ranged from 13 to 80 mm Hg. Maternal oxygen tensions were controlled by changing the inspired oxygen concentrations (20, 33.3, 50, or 100 per cent); Pao2 ranged from 78 to 500 mm Hg. Umbilical vein Po2 and Pco2 of the newborn varied according to the maternal level. Foetal Pco2 was always higher than maternal Paoo2; the mean maternal-foetal gradient was 11.3 mm Hg (SD 4.7). Foetal Po2 was positively correlated with maternal Pao2 within the range 78 to 200–300 mm Hg, but was not correlated with further elevation of maternal Pao2 from 200 to 500 mm Hg. This might be attributed to the shape of Hbo2 dissociation curve.

Negative Bohr effect in newt haemolysates and its regulation.

THE HbO2 dissociation curves of haemolysates of the newt (Triton cristatus) have been studied at different temperatures. Blood samples were collected from single animals in 0.6 per cent NaCl solution containing EDTA as anticoagulant and centrifuged to remove the serum. The packed washed red cells were then treated with distilled water containing a drop of CC14 and haemolysates were separated in a Sorvall refrigerated centrifuge at 15,000 r.p.m.

Pulmonary circulation and oxygen transport in lambs at high altitude

The oxygen transport and pulmonary hemodynamics of lambs native to low altitude were evaluated in Denver and on Mount Evans (12,700 ft.). Because the Hb-O2 dissociation curve is placed well to the right of most other mammals, markedly depressed arterial O2 saturations (59%) occurred at high altitude. However, the lambs adapted remarkably well and showed normally rapid growth. The mixed venous Po2 was relatively well maintained, primarily by a narrowing of the A-V Po2 gradient to 11 mm Hg. Despite the marked hypoxemia, elevation of the pulmonary artery pressure was not a consistent finding, and when it occurred it was neither marked nor sustained.