Pulse dye densitometry using indigo carmine is useful for cardiac output measurement, but not for circulating blood volume measurement.
OBJECTIVE
We evaluated the validity of a newly developed pulse dye densitometer for indigo carmine for measuring cardiac output and circulating blood volume.


METHODS
Measurements of cardiac output and circulating blood volume were performed with the indigo carmine densitometer during normovolaemia, hypovolaemia and hypervolaemia in nine mongrel dogs under general anaesthesia. The validity was evaluated by comparison of the values of cardiac output and circulating blood volume obtained by the thermodilution technique and the 51Cr-labelled red blood cell method, respectively. We also examined indigo carmine removal by continuous veno-venous haemofiltration after indigo carmine injection.


RESULTS
There was good agreement between dye densitometer- and thermodilution-derived cardiac output (r = 0.885, P < 0.001). The bias and limits of agreement of these values were 0.09 and+/-1.07 L min(-1) (2 SD, n 22), respectively. The dye-densitometer-derived circulating blood volume was greater than that of the 51Cr-labelled red blood cell method, and both values showed weak agreement (r = 0.587, P < 0.027). The sieving coefficient of indigo carmine through continuous veno-venous haemofiltration was 0.34+/-0.06.


CONCLUSIONS
These data indicate that indigo carmine densitometry is a reliable method for cardiac output determination, but it overestimates circulating blood volume, probably due to the transition of indigo carmine into the extravascular space in the systemic circulation.
Fujita
Y
Y
Kawasaki Medical School, Departments of Anesthesiology and ICM, Japan. fujitay@med.kawasaki-m.ac.jp
Yamamoto
T
T
Fuse
M
M
Kobayashi
N
N
Takeda
S
S
Aoyagi
T
T
D000465:Algorithms; D000818:Animals; D001810:Blood Volume / Q000502:physiology*; D002302:Cardiac Output / Q000502:physiology*; D002860:Chromium Radioisotopes; D004396:Coloring Agents; D003720:Densitometry; D004285:Dogs; D004912:Erythrocytes / Q000378:metabolism; D006440:Hemofiltration; D020896:Hypovolemia / Q000175:diagnosis; D007203:Indigo Carmine; D015203:Reproducibility of Results; D013815:Thermodilution
D002860:Chromium Radioisotopes; D004396:Coloring Agents; D007203:Indigo Carmine