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Biomedical subjects

D Z Frankel

Publications and source records attributed to D Z Frankel.

4 recordsLinked to original sources
PubMed1979

A new method for measuring PCO2 during anaesthesia.

We have evaluated a new method for measuring the oxygenated mixed venous PCO2 (PVCO2) in patients undergoing general anaesthesia. The lungs were inflated with a gas mixture containing 0% carbon dioxide and then 12% carbon dioxide and the expired gas was analysed both before and after a brief period of breath-holding. PVCO2 was estimated from the differences in carbon dioxide concentration before and after the apnoeic period. Simultaneous measurments of PaCO2 were made in blood obtained from radial artery puncture. The range of PaCO2 studied was 3.2--6.13 kPa. The relationship between mixed venous and arterial PCO2 was found to be PaCO2 = 0.87 PVCO2--0.44 (r = 0.91). We conclude that this method for measuring PVCO2 can be used during anaesthesia allowing PaCO2 to be estimated with considerable accuracy.

Adult↗
PubMed1978

The linear relation of cerebral blood flow to arterial oxygen saturation in hypoxic hypoxia induced with nitrous oxide or nitrogen.

This study has demonstrated a linear relationship between cerebral blood flow and arterial oxygen saturation (Sao2) in the cerebral blood flow response in the hypoxic range of Pao2 values, which we believe is documented for the first time. The cerebral blood flow increased 1.02 per cent for each percentage decrease in Sao2 in hypoxia induced with nitrogen. Hypoxia induced with nitrous oxide increased cerebral blood flow at the rate of 2.09 per cent for each one per cent decrease in Sao2 which was dramatically more than the increase associated with hypoxia induced with nitrogen. Increased survival rates at lower Sao2 levels suggested that nitrous oxide also exerts a protective effect on dog myocardium. The mechanism by which hypoxia increases cerebral blood flow is unclear but the prevalent theory is one of neurogenic control which causes cerebral blood flow to increase as the intracellular hydrogen ion ([H+]I) increases in the progressive lactacidosis of hypoxia. The demonstration of a linear relationship between cerebral blood flow and Sao2 will provide the statistician, the researcher and the clinician with a useful tool for the neurophysiological assessment of cerebral blood flow.

Animals↗
PubMed1978

A noninvasive method for measuring the PCO2 of mixed venous blood.

A breath-holding method for measuring the PCO2 of mixed venous blood has been developed. Two gas mixtures, 100 per cent O2 and 12 per cent CO2 in O2, were inspired, and the expired gas was analyzed after 5 and 15 sec of breathholding. The oxygenated mixed venous PCO2 was calculated using an exponential equation. The method was applied in healthy subjects, patients with lung disease, and unconscious mechanically ventilated patients. The mixed venous PCO2 correlated well with arterial PCO2 (r = 0.96), the PCO2 obtained by rebreathing (r = 0.97), and the PCO2 in blood drawn from the pulmonary artery (r = 0.97). The method is noninvasive, has a low coefficient of variance, and allows arterial PCO2 to be estimated by multiplying the breath-holding mixed venous PCO2 by 0.8.

Adult↗