RETINYL PALMITATE INJECTIONS REDUCE SERUM LEVELS AND EFFECTS OF ENDOTOXIN ON SYSTEMIC HEMODYNAMICS AND OXYGEN-TRANSPORT IN THE PIG

Background: Retinyl palmitate [(RP) 230 IU.kg(-1)] modulates the circu latory and respiratory responses of a subsequent infusion of endotoxin in the pig. The aims of this study were: I. To determine if RP (2300 IU.kg(-1)) affects the serum endotoxin levels in this model. II. To ev aluate the effect of this dose of RP on circulatory and respiratory va riables in our porcine model. III. To investigate the levels of RP and neutrophil count in porcine endotoxaemia. Methods: Ten anaesthetized pigs were randomly given 2300 IU.kg(-1) of RP or the solvent i.m. prio r to the continuous i.v. infusion of E. coli endotoxin (10 mu g.kg(-1) .h(-1)). Another 4 sham animals were given either i.m. RP (n=2) or i.m . solvent (n=2) followed by an infusion of saline. Haemodynamics and o xygen extraction were monitored and samples taken for analysis of endo toxin, RP and blood cells. Results: I. Endotoxin levels in serum were lower (P<0.001) in the RP-pretreated pigs. II. These animals had highe r cardiac index (P<0.05), mean arterial pressure and left ventricular stroke work index (both P<0.001), and lower oxygen extraction (P<0.01) . III. RP-Pre=pretreatment caused a paradoxical decrease in serum reti nyl (P<0.001) and a more rapid restitution of neutrophil count (P<0.05 ). Conclusion: Pretreatment with RP (2300 IU.kg(-1)) counteracts the p rogressive increase in serum endotoxin levels in porcine endotoxaemia.