Capillary Refill Time versus Combination of Laser Doppler Flowmetry and White Light Spectrometry for Monitoring of Peripheral Microcirculation in Neonates and Infants following Palliation or Repair of Complex Congenital Heart Disease

Objectives: Compared with biventricular corrected children, children after univentricular palliation utilizing a systemic-to-pulmonary shunt are at higher risk for deficient organ perfusion caused by a reduced systemic blood flow due to the diastolic run-off of the shunt. It is common clinical practice to monitor postoperative microperfusion in children by measuring the capillary refill time (CRT). The method “oxygen to see” (O2C) uses a combination of laser Doppler flowmetry and white light spectrometry to measure the absolute oxygen saturation (StO2), the relative hemoglobin content (rHb) and the relative blood flow (Flow) in tissue. The aim of this study was to evaluate the correlation between the clinical examination of CRT and the O2C method, and to compare the peripheral microperfusion in children after cardiac surgery resulting in biventricular repair with children following neonatal palliation of functionally univentricular hearts.

Methods: We analyzed peripheral microperfusion of 83 neonates and infants with CHD following biventricular repair (n = 59; average age, 16 weeks; average weight, 5.17 kg) or neonatal palliation including a systemic-to-pulmonary shunt (n = 24; average age, 3.5 weeks; average weight, 4.2 kg). We compared the CRT with StO2, rHb, and flow measured by the O2C method in thumb and foot tissue. Each child was examined at two points of time first within 24 hours and the second 24 to 48 hours after surgery.

Result: The analysis showed a statistically significant correlation between the CRT and the three O2C parameters both on upper and lower extremity. There was no statistical difference in peripheral microperfusion between both groups determined by O2C and CRT.

Conclusion: Results by O2C correlated very well with CRT. O2C seems to be a feasible method to further investigate the microperfusion in peripheral tissue. It provides additional interesting information including regional tissue oxygen saturation, the relative hemoglobin content and blood flow, and may be used to obtain quantifiable parameters in future hemodynamic research. Despite a reduced windkessel function following neonatal palliation with a systemic-to-pulmonary shunt, hemodynamic stable children with functionally univentricular hearts seem to have no difference in the microperfusion of peripheral tissue, compared with children after biventricular repair.