[Intrapleural catheter analgesia in patients with multiple rib fractures]

Patients with multiple rib fractures often suffer from severe pain that impairs their respiratory performance. The effect of interpleural administration of bupivacaine (20 ml 0.25% every 4 h) for pain management was evaluated in ten patients. The initial interpleural injection resulted in significant pain relief and improvement of arterial oxygen tension. Two patients needed additional i.v. injections of opioids (piritramide 15-22.5 mg/24 h). In one patient a small asymptomatic pneumothorax was observed following placement of the catheter, which resolved spontaneously. No other complications were reported. In an intraindividual comparison, bupivacaine alone and bupivacaine plus epinephrine 1:200,000 were compared with regard to pharmacokinetics of bupivacaine, analgesic effect, side effects, and respiratory performance. The addition of epinephrine yielded only minor advantages from a pharmacokinetic point of view (median peak concentration of bupivacaine 1.8 micrograms/ml vs 2.0 micrograms/ml for bupivacaine alone). The quality and duration of analgesia and the effects on respiration were not influenced by epinephrine. The heart rate was significantly higher and the blood pressure significantly lower when epinephrine was added to the solution. Nevertheless, these differences were too small to be of clinical importance. Even though maximum total plasma concentrations of bupivacaine above 2 micrograms/ml were found in some patients, there were no signs of CNS toxicity, most probably because of the increased protein binding of bupivacaine following trauma. Accordingly, the maximum free plasma concentrations in all patients were below the threshold level of 0.24 micron/ml. We therefore conclude tht interpleural administration of bupivacaine could be a valuable means of pain relief in patients with multiple rib fractures, providing no severe pulmonary contusions or concomitant injuries are present.