Background: CBF measurement by near infrared spectroscopy (NIRS) using oxy (CBF-oxy) needs rapid changes in SaO2 which often cannot be achieved. An alternative, using ICG (CBF-icg) has been developed and values compared. Subjects: 6 ventilated infants (age 26-38 weeks, birth weight 0.885-3.730 kg). Interventions: For CBF-icg: ICG was injected via an umbilical venous catheter (0.1 mg.kg-1); blood [ICG] measured by an umbilical artery catheter; and brain [ICG] by NIRS. CBF-oxy was measured as before (Lancet 1988;2:770). CBF was measured using each method repeatedly before and after altering PaCO2. Results: PaCO2 ranged from 4.0-6.8 kPa. Mean CBF-icg = (1.13*meanCBF-oxy)-2.76 mL.100g-1.min-1 (r=0.93). The mean difference was -0.25 (limits of agreement 6.3 to -6.8) mL.100g-1.min-1. Conclusion: The methods are in good agreement. Intravenous ICG dye can be used as a tracer for CBF measurements in very sick infants.
Supported by the British Heart Foundation.
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Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences (1997)