Rapid measurement of indocyanine green retention by pulse spectrophotometry: a validation study in 70 patients with Child-Pugh A cirrhosis before hepatectomy for hepatocellular carcinoma.
BACKGROUND
The indocyanine green (ICG) retention test is the most popular liver function test for selecting patients for major hepatectomy. Traditionally, it is done using spectrophotometry with serial blood sampling. The newly-developed pulse spectrophotometry is a faster alternative, but its accuracy on Child-Pugh A cirrhotic patients undergoing hepatectomy for hepatocellular carcinoma has not been well documented. This study aimed to assess the accuracy of the LiMON(®), one of the pulse spectrophotometry systems, in measuring preoperative ICG retention in these patients and to devise an easy formula for conversion of the results so that they can be compared with classical literature records where ICG retention was measured by the traditional method.


METHODS
We measured the liver function of 70 Child-Pugh A cirrhotic patients before hepatectomy for hepatocellular carcinoma from September 2008 to January 2009. ICG retention at 15 minutes measured by traditional spectrophotometry (ICGR15) was compared with ICG retention at 15 minutes measured by the LiMON (ICGR15(L)).


RESULTS
The median ICGR15 was 14.7% (5.6%-32%) and the median ICGR15(L) was 10.4% (1.2%-28%). The mean difference between them was -4.3606. There was a strong correlation between ICGR15 and ICGR15(L) (correlation coefficient, 0.844; 95% confidence interval, 0.762-0.899). The following formula was devised: ICGR15=1.16XICGR15(L)+2.73.


CONCLUSIONS
The LiMON provides a fast and repeatable way to measure ICG retention at 15 minutes, but with constant underestimation of the real value. Therefore, when comparing results obtained by traditional spectrophotometry and the LiMON, adjustment of results from the latter is necessary, and this can be done with a simple mathematical calculation using the above formula.
Department of Surgery, the University of Hong Kong, Hong Kong, China. tantocheung@hotmail.com
Tan To
TT
Cheung
See Ching
SC
Chan
Kenneth S H
KS
Chok
Albert C Y
AC
Chan
Wan Ching
WC
Yu
Ronnie T P
RT
Poon
Chung Mau
CM
Lo
Sheung Tat
ST
Fan
D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D016009:Chi-Square Distribution; D004396:Coloring Agents; D005260:Female; D006498:Hepatectomy; D006723:Hong Kong; D006801:Humans; D007208:Indocyanine Green; D008103:Liver Cirrhosis / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D008111:Liver Function Tests / Q000295:instrumentation; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013053:Spectrophotometry / Q000295:instrumentation; D013997:Time Factors
D004396:Coloring Agents; D007208:Indocyanine Green