抄録
It was well known that there was good correlation between the cardiac output (CO) calculated by impedance plethysmography (IMP) and CO measured by other methods such as Fick's method and dye dilution method, but CO calculated by the former method including pulmonary circulation has proved larger than that measured by the latter method.
This study is aimed at recording IMP more easily to save aluminized tape electrodes and to avoid overestimating CO by IMP.
After measuring CO by IMP utilizing 4 aluminized tapes surrounding the thorax, the 4 tapes were cut at bilateral axillary lines and CO contents were measured by 4 kinds of half-taped methods : both upper halves at the neck and abdomen (Up-Up), both lower halves at the neck and the abdomen (Down-Down), upper half at the neck and lower half at the abdomen (Up-Down) and lower half at the neck and upper half at the abdomen (Down-Up).
CO volumes calculated in 22 patients by Up-Down method were correlated best (r=0.89), among the 4 kinds of half-taped methods, with Kubicek's method and they had the best equality (y=-0.02+1.03x). In 14 patients without shunt and regurgitant heart diseases, CO volumes were measured simultaneously both by Up-Down half-taped method and by Fick's method. The results were correlated well (r=0.91) but CO by Up-Down half-taped method was smaller than by Fick's method (y=0.11+1.39x), as some of subjects (60±11 years old) had pulmonary emphy-seme and increased the transthoracic impedance Z0 (Z0=31+5Ω).
From this study, it has been concluded that IMP using an Up-Down half-taped method could be recorded more easily than the usual method as there was a harmless influence of female breasts and long cut hair and that CO by this convenient half-taped method was correlated well not only with CO by IMP according to Kubicek's method but also with CO obtained from Fick's method. These conclusions showed usefulness of this convenient half-taped method of IMP.
