The effect of acetylcholine upon arterial saturation

Schlant, Robert C.; Tsagaris, Theofilos J.; Robertson, Robert J.; Winter, Thorne S.; Edwards, Freya

doi:10.1016/0002-8703(62)90037-6

Cited by 7 publications

(1 citation statement)

References 37 publications

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“…This discrepancy suggests that the problem cannot have a simple shunt explanation. The question has been raised by other writers (Keys and Snell, 1938;Schlant et al, 1962) that the red cells may have a defective ability for immediate oxygen uptake. However, when the hypoxic blood of our patients was exposed to ordinary atmospheric oxygen tension (105 mm.…”

Section: Discussionmentioning

confidence: 99%

Use of Krypton-85 in the Study of Hypoxia in Porto-pulmonary Bilharziasis (Schistosomiasis)

Zaky¹,

El-Heneidy²,

Khalil³

1964

BMJ

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BRITS 1021observations it was found that the immediate effect of the adrenergic drugs was similar.To obtain a measure of the duration of effect of the different inhalants, serial assessments were continued for three and a half hours after each inhalant therapy on two groups of asthmatic subjects containing 12 subjects in each group. From these serial studies it was found that the inhalants gave distinct time-response curves.The duration of isoprenaline was shortest; its action had been completely lost by 90 Porto-pulmonary bilharziasis often presents as hepatosplenomegaly and cor pulmonale (Zaky, 1952 ; Zaky et al., 1959). The haemodynamic changes in this disease have already been discussed Zaky et al., 1962). We found that in about 10% of these cases hypoxia of less than 94% was present. This hypoxia could not be corrected by 100% 02 inhalation.When the alveolar CO2 tension was matched simultaneously against the arterial CO2 tension either at rest or on moderate exercise, a significant gradient was found between the alveolar Pco2 and the arterial Pco2, the latter being raised from 2 to 7 mm. Hg. Studies of pulmonary function in these cases revealed almost normal findings (Ashba, 1959), particularly the minute alveolar ventilation and the helium-mixing time. These findings can only mean a veno-arterial admixture either inside the lung from pre-capillary pulmonary-artery/pulmonary-vein shunting or from the portal-vein blood to the pulmonary vein. In order to elucidate the above findings it was decided to carry out further investigations using the gas krypton-85. Materials and MethodsKrypton-85 is a very interesting gas in that it is cleared by the alveoli to the extent of 95-99% in one circulation. We followed the method described by Fritts et al. (1960) to investigate the problem of a pre-capillary pulmonary-artery/ pulmonary-vein shunting. By this method a gas solute is injected with a known quantity of a blue dye into the superior vena cava and both are recovered from the brachial artery within the period of one circulation. The concentration of dye is obtained from spectrophotometer readings, while the radioactivity is read on the scaler. The percentage of shunt is calculated from the formula: 85Kr counts in integrated radialxconc. of dye injected mg.11. x100 85Kr counts injected x conc. of dye in integrated radial mg./I.The pulmonary-artery concentrations after injection into the superior vena cava were calculated from the radiological size of the heart after the method of Hanson (1961), and the ratio of the right to the left cavities was considered to be 55-45%. This gave the cardiac volume in which the dilution of superiorvena-cava injection could have taken place.To investigate the problem of portal-vein/pulmonary-vein shunting, the same amount of krypton-85 was injected into the splenic pulp in bolus form; the bilharzial spleen lends itself admirably for the purpose as it is easily accessible and firm. We had no trouble while using this route in our case apart from a moderate degree of pain after the...

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Section: Discussionmentioning

confidence: 99%