Surfactant Administration and the Cerebral Circulation

Abstract

We have used two main techniques to investigate the effect of surfactant therapy on the cerebral circulation in 34 babies. Twenty-one babies were studied using near infrared spectroscopy and 13 had cerebral blood flow measured using a xenon clearance technique. Other measures recorded included amplitude integrated EEG, mean arterial blood pressure and central venous or oesophageal pressure. There was a marked depression in EEG activity lasting for 10–20 min after surfactant administration. Cerebral blood volume and cerebral blood flow were maintained in most infants in spite of a fall in mean arterial blood pressure. We conclude that factors other than cerebral ischaemia cause the transient disturbance in electrophysiologic activity.

Rapid Tracheal Infusion of Surfactant versus Bolus Instillation in Rabbits: Effects on Oxygenation, Blood Pressure and Surfactant Distribution

“…Hypotheses are: Hellstrom-Westas et al [8] and Skov et al [9,10] noticed a marked skin flush in children after instillation of sur factant and concluded that a general vasodila tion could be a reason for the blood pressure decrease. Considering the continuous level of 6 cmHiO PEEP and the rapid rise of the func tional residual capacity after CS instillation [32], an increase in the pulmonary vascular resistance causing a decrease in cardiac out put could be another explanation for the drop in blood pressure.…”

“…The standard method of tracheal bolus instillation was derived from animal studies showing that the direct instilla tion of surfactant into the trachea improves oxygenation better and longer than delivery as an aerosol [5,6], However, undesirable side effects of bolus instillation have been re-ported, such as a transient decrease in blood pressure [7][8][9][10], changing cerebral blood flow velocity and cerebral blood volume [8, 9,11,12], as well as arterial carbon dioxide tension (PaCOy) changes [5,10]. The link between surfactant substitution and these circulatory disturbances is unknown.…”

Update on Surf actant Therapy

“…The finding of EEG suppres sion in infants with increased blood pressure suggests a noncirculatory aetiology of this phe nomenon. Previous studies have confirmed that cerebral ischaemia is not the cause of the EEG suppression [8,9].…”

Circulatory Effects of Surfactant Therapy

“…In a scries of studies from Skov et al [4,5] and Hellstrom-Westas et al [6] instillation of 200 mg/kg of Curosurf® decreased mean ar terial blood pressure (MABP) by a mean of 8-9 mmHg within 1-2 min with recovery to baseline levels usually occurring within 5 min.…”

“…Using near infrared spectroscopy (NIRS) Skov et al [4,5] observed a decrease in cere bral oxygenated hemoglobin associated with Circulatory Effects of Surfactant Therapy an increase in cerebral blood volume, but no significant change in cerebral blood flow (CBF). Applying the xenon clearance tech nique for CBF measurement, Bell ct al.…”