Abstract

Objective: The rapid improvement of lung function after exogenous surfactant treatment for respiratory distress syndrome (RDS) can affect the functions of several other systems, which includes cerebral blood flow volume (CBF). To evaluate the change in CBF after treatment with exogenous surfactant, we measured CBF in a newborn piglet model with RDS.

Method: After the lung lavage with normal saline, ten animals under mechanical ventilation were administered either 120 mg/kg surfactant-TA (Surfacten^®) or air placebo. Heart rate, blood pressure, dynamic lung compliance (Cdyn), PaO₂, PaCO₂, and CBF were recorded before and every 15 min after surfactant treatment up to 120 min.

Results: Cdyn was improved significantly at 45 min and later after treatment; that of the control group remained unchanged. PaO₂ increased and PaCO₂ decreased significantly after surfactant treatment in both groups. However, the improvement was significantly less in the control group. CBF significantly decreased by about 30% in the control group, and by about 50% in the treated group at 120 min, with a significant difference between groups. Almost 70% of the changes in CBF were attributable to changes in PaCO₂ by multivariate regression analysis.

Conclusions: Treatment with exogenous surfactant improves lung compliance, and has little effect on CBF itself. The drop in levels of PaCO₂ after treatment, however, had a strong relationship with decreases in CBF.