Hemodynamic effects of interpleural analgesia in pigs

Six anesthetized pigs received bupivacaine 2 mg/kg with epinephrine 2 micrograms/kg interpleurally while six saline injected animals served as controls. The animals were monitored hemodynamically for 120 min after injection. There were no significant changes in hemodynamic variables in the control group. In the group receiving bupivacaine with epihephrine there was a pattern of increase in mean arterial blood pressure, systemic vascular resistance and mean pulmonary arterial blood pressure after 60 min of observation. There were no other significant changes in pulmonary or systemic hemodynamics or gas exchange as evaluated by blood gases or whole body oxygen consumption. It is speculated that the increased systemic vascular resistance was an effect of the epinephrine added to the anesthetic. Interpleural analgesia may be a safe pain-relieving method even in slightly hypovolemic individuals.