Effects of abdominal hot compresses on indocyanine green elimination – a randomized cross over study in healthy subjects

BACKGROUND: Hot compresses on the right upper abdomen are used as support for patients with liver diseases in Germany. The study was designed to determine, whether they affect hepatic blood flow. METHODS: Single dose kinetics of indocyanine green (ICG) were studied in 13 healthy subjects with or without hot compresses on the right upper abdomen over 40 minutes. The time interval between the investigations was 8 days, the sequence was randomly assigned. RESULTS: Within non-linear kinetic analyses the area under the curves (AUC) were 23% (95% confidence interval [CI]: 5–37%) lower with hot compresses. In the initial phase, however, no differences were detected (p = 0.295). The differences occurred only in the late phase after 30–40 minutes, when the genuine ICG is eliminated from the plasma and only the degradation product remains. CONCLUSION: Hot compresses have no effect on ICG elimination in healthy subjects but seem to affect the elimination of ICG metabolites. TRIAL REGISTRATION: ClinicalTrials.gov NCT00484913