[A method to predict pulmonary blood flow by nitrous oxide washout curve].
The study was performed to obtain a relationship between the pulmonary blood flow and the tau b (time constant) calculated from multiple-breath nitrous oxide (N2O) washout curve. Elimination of N2O depends on pulmonary blood flow and alveolar ventilation. From the theoretical consideration, tau b can be calculated by the following formula; tau b = Vd[1/Qt-Qs) + 0.47/VA) Vd = N2O volume of distribution in the body Qt = cardiac output, Qs = shunt blood flow VA = alveolar ventilation. Relationship between observed Qt-Qs and observed tau b was admitted to the predicted formula. The method was compared with the thermodilution method in almost simultaneous measurement of the cardiac output. A good correlation was obtained between them (r = 0.87). Washout curve of nitrous oxide can be used for a reliable measurement of pulmonary perfusion.
Nomoto
Y
Y
Department of Anesthesiology, Tokyo National Chest Hospital.
Ikegami
T
T
Ohtsaka
Y
Y
Nagayama
N
N
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008722:Methods; D008875:Middle Aged; D009609:Nitrous Oxide; D011652:Pulmonary Circulation
D009609:Nitrous Oxide