Clearance of indocyanine green as an index of liver function during cyclopropane anaesthesia and induced hypotension.

The rate of decrease in the plasma concentration of indocyanine green (ICG) following a bolus i.v. injection has been studied in two groups of patients before and during anaesthesia. In eight patients anaesthetized with nitrous oxide and oxygen, and who received a neuromuscular blocking drug, induction of anaesthesia was not associated with a significant change in ICG half-life (from 4.59 to 3.85 min) but the subsequent administration of cyclopropane was associated with a statistically significant increase to 5.61 min. In a second group of anaesthetized patients, breathing spontaneously a mixture of oxygen, nitrous oxide and halothane, the induction of arterial hypotension with either lumbar extradural block or sodium nitroprusside was not associated with significant changes in ICG half-life.