Blood O₂ content measurements using the oxygen electrode

Abstract

A method is described for determining the oxygen content in whole blood with the membrane-covered oxygen electrode that requires less time and skill than the Van Slyke-Neill technique. A blood sample (0.05 ml) is mixed with a large volume of dilute (0.2% w/v) potassium ferricyanide solution in equilibrium with ambient air and the oxygen tension of the mixture is measured at a known temperature. The whole-blood oxygen content is obtained by subtracting the calculated O2 content of the ferricyanide solution from that of the blood-ferricyanide mixture. The method is based on the assumption that the Bunsen O2 solubility coefficient of the ferricyanide solution, with or without the added blood sample, is equal to the solubility coefficient of water. Data have been presented to validate this assumption. Whole-blood O2 contents measured simultaneously with the oxygen electrode and the Van Slyke-Neill technique were found to be in close agreement. flood-gas determination Submitted on January 11, 1965

The Response of Patients With Respiratory Failure and Cardiopulmonary Disease to Different Levels of Constant Volume Ventilation

“…All patients were supine and horizontal; each had a cuffed tracheostomy tube with an airtight fit in place. Controlled (4). All measurements were required to agree to within i 0.2 vol per 100 ml for any particular sample.…”

“…Under these circumstances the physiologic shunt has been called the "true," "pure," or "anatomical" shunt, or the "direct" venous admixture component (12). 4 In the first measurement in Patient 3 and in the first four measurements in Patient 11 (Table III) more than 2% nitrogen was present in mixed expired gas (due to entrainment of air into the inspired 100% oxygen), and PAo2 was assumed to equal PEO2 + PFCo2-superior vena caval samples to estimate mixed venous blood oxygen content is a compromise dictated by the practicalities of clinical care. In resting normal man, superior vena caval oxygen levels are lower than those of mixed venous blood (15); in anesthetized man during intermittent positive pressure ventilation the average superior vena caval blood oxygen content is 0.25 vol per 100 ml higher than the average mixed venous blood oxygen content (16).…”

Simultaneous determination of hemoglobin derivatives, oxygen content, oxygen capacity, and oxygen saturation in 10 microliters of whole blood.

“…The total oxygen of a volume (V0) of borate buffer is given by equation 2. After addition of a volume (VB) of blood, 02't = apo2"Vo + [Hb02]V0 -apo2Vp (10) where apo2"Vo is the physically dissolved oxygen;…”

Oxygen therapy

“…61 Subsequent modifl.cations have described the technique in greater detail. 7,140,152,202 Laver and co-workers 140 in 1965 proposed that 0.05 ml. of blood could be drawn into a graduated capillary which was then evacuated into a known amount of dilute (0.2 per cent) potassinm ferricyanide solution in equilibrinm with air; the blood was thus lysed and the resultant oxygen tension was then measured.…”