H. Segerer et al., PULMONARY DISTRIBUTION AND EFFICACY OF EXOGENOUS SURFACTANT IN LUNG-LAVAGED RABBITS ARE INFLUENCED BY THE INSTILLATION TECHNIQUE, Pediatric research, 34(4), 1993, pp. 490-494
Surfactant bolus instillation has been reported to cause changes in ar
terial blood pressure (BP) and cerebral blood flow velocities which ma
y increase the risk of intraventricular haemorrhage. To avoid these ef
fects, slow tracheal infusion was evaluated as a possible alternative
method of surfactant administration. Saline lung lavages were performe
d in 13 anesthetized and artificially ventilated adult rabbits to prod
uce respiratory distress syndrome. Curosurf (CS, 200 mg/kg) labeled wi
th C-14-dipalmitoyl-phosphatidylcholine (-DPPC) and/or red microsphere
s (RMS) was instilled into the trachea either as a single bolus (n = 8
) or by infusion during 45 min via a side-channel within the wall of t
he tracheal tube (n = 5). An arterial cannula was placed for monitorin
g of blood gases and BP. To determine surfactant distribution, the lun
gs were cut into 60-70 pieces and radioactivity and/or the number of R
MS were measured in each piece. The distribution of RMS was closely re
lated to the distribution of C-14-DPPC (r = 0.96). Bolus instillation
of CS led to a prompt and sustained increase in PaO2 (from <10.5 to >4
0 kPa within 2 min), a transient decrease in BP, and a reasonably homo
geneous pulmonary surfactant distribution. Tracheal infusion of CS cha
nged neither BP nor PaO2 during the observation period of 60 min. The
pulmonary distribution of CS was extremely uneven after infusion. The
distribution of exogenous surfactant and its effects on gas exchange a
re influenced by the instillation method. An inadequate instillation t
echnique may add to the causes of ''poor response'' after surfactant r
eplacement.