Cerebral hemodynamics after exogenous surfactant administration for respiratory distress syndrome in piglet model

Objective: The rapid improvement of lung function after exogenous surfactan t treatment for respiratory distress syndrome (RDS) can affect the function s 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 mechani cal ventilation were administered either 120 mg/kg surfactant-TA (Surfacten (R)) or air placebo. Heart rate, blood pressure, dynamic lung compliance (C dyn), PaO2, PaCO2, and CBF were recorded before and every 15 min after surf actant treatment up to 120 min. Results: Cdyn was improved significantly at 45 min and later after treatmen t; 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 significan tly decreased by about 30% in the control group, and by about 50% in the tr eated group at 120 min, with a significant difference between groups. Almos t 70% of the changes in CBF were attributable to changes in PaCO2 by multiv ariate regression analysis. Conclusions: Treatment with exogenous surfactant improves lung compliance, and has little effect on CBF itself, re drop in levels of PaCO2 after treat ment, however, had a strong relationship with decreases in CBF.