Modified ultrafiltration (MUF) can be performed in infants with ventricular septal defects (VSDs) after cardiopulmonary bypass (CPB) to reduce haemodilution and its potential adverse effects. High-flow MUF might reduce ultrafiltration duration and hasten the necessary correction of haemodilution during CPB. However, its influence on brain oxygenation remains controversial.

This non-randomized, prospective, pilot study aimed to investigate the influence of high-flow MUF on brain oxygenation in infants with VSDs.

High-flow MUF (≥20 mL/kg/min) was performed in twenty infants. Brain oxygen saturation (rSO₂) and tissue haemoglobin index (tHI) were non-invasively and continuously measured intraoperatively using near-infrared spectroscopy (NIRS). Transcranial Doppler non-invasively detected the mean flow velocity of the middle cerebral artery (Vmean).

rSO₂ increased significantly during MUF, as did tHI, Vmean, mean arterial pressure and haematocrit (all p<0.05). No correlation was found between changes in rSO₂ and changes in other parameters (all p≥0.05).

In infants with ventricular septal defects managed with CPB during VSDs repair, high-flow MUF did not reduce brain oxygenation.