Objective: To investigate the effect of a thermal injury an pulmonary surfa
ctant phosphatidylcholine kinetics,
Design:
Random, controlled study, Setting: University research laboratory.
Subjects: Yorkshire swine (n = 8) with and without a 40% total body surface
area burn.
Interventions: A new isotope tracer methodology was used to quantify surfac
tant phosphatidylcholine kinetics. Four days after burn, [1,2-C-13(2)]aceta
te and [U-C-13(16)]palmitate were infused continuously for 8 hrs to quantif
y surfactant phosphatidylcholine synthesis, secretion, recycling, and irrev
ersible loss.
Measurements and Main Results:The total surfactant phosphatidylcholine pool
size was reduced from the control value of 2.65 +/- 0.05 to 1.61 +/- 0.08
mu mol/g wet lung in burned animals (p < .05), as was the proportional cont
ribution of palmitate to lung surfactant phosphatidylcholine composition. T
his reduction was associated with a significant decrease in lung dynamic co
mpliance from the control Value of 66 +/- 6 to 55 +/- 6 mL/cm H2O for burne
d pigs (p < .05). The most prominent response of lung phosphatidylcholine k
inetics was a decrease in the total lung phosphatidylcholine synthesis from
a central value of 12.7 +/- 1.2 to 5.5 +/- 0.3 nmol phosphatidylcholine-bo
und palmitate.hr(-1).g of wet lung(-1) in burned animals (p < .05).
Conclusions: Pulmonary phosphatidylcholine content and palmitate compositio
n decrease after burn injury because of a decrease in the rate of phosphati
dylcholine synthesis. These responses likely contribute to impaired lung co
mpliance.