Hydrogen in the Detection of Minute Left-to-Right Shunts

Wennevold, A. Hydrogen in the Detection of Minute Left-to-Right Shunts. Scand. J. din. Lab. Invest. 19, 181-185, 1966. Experience with the hydrogen electrode technique in 124 patients is reported; 24 of the patients had a left-to-right shunt so small that it could not be detected by determination of oxygen saturation. The appearance time in the pulmonary artery was 41/2 seconds or more in all the cases without shunt and never exceeded 4 seconds in cases with a shunt. In borderline cases the difference between the appearance time in the superior caval vein and the time in the pulmonary artery may give additional information as to the presence or absence of a shunt.