Introduction Contrasting evidences exist regarding the possible effects of surfactant administration on cerebral perfusion. Aim of this study was to compare changes in cerebral hemodynamics and oxygenation following a 100 mg/kg and 50 mg/kg dose of bovine surfactant.

Methods 17 Infants of mean gestational age (GA) 29 ± 2.7 weeks (24-35), mean birth weight (BW) 1078 ± 358 g (600-1840), received a 100 mg/kg bolus dose of bovine surfactant (Alveofact); 8 infants of GA 29.2± 2.2 weeks (26-32), BW 1123 ± 406 g (660-1650) received 50 mg/kg of natural surfactant. Near infrared spectroscopy (NIRS-NIRO Hamamatsu Photonics KK) was used to assess relative changes in oxyhemoglobin(ΔHbO2), deoxyhemoglobin (ΔHb), oxidized cytochrome aa3 (ΔCytO2) and cerebral blood volume (ΔCBV), derived from total hemoglobin (HbT). Changes were calculated at 1, 5, 15, 30 and 60 minutes after surfactant administration.

Results: mean values are summarized in the following table. * p < 0.05 vs baseline.

Table 1
Full size table

Conclusion We observed a rapid and sustained increase in CBV after a 100 mg/kg dose of natural surfactant; an initial rise in HbO2, probably due to increased cerebral blood flow of well oxygenated blood, was followed by a rise in cerebral Hb and a decrease in CytO2. The same trend was seen after 50 mg/kg but the magnitude of CBV and Hb increase and CytO2 fall was less pronounced, even with no statistically significant difference between the two groups. These findings can be related to: 1) an impaired venous return, possibly depending on partially obstructed intrathoracic circulation due to increased trasmission of ventilatory pressure or to 2) an increased production of vasodilating substances (PAF, Nitric Oxide, etc).