Early tracheal extubation has become common after cardiac surgery.
Anesthetic techniques designed to achieve this goal can make immediate postoperative
analgesia challenging. We conducted this randomized, placebo-controlled, double-blind study to investigate the effect of a parasternal block on postoperative
analgesia, respiratory function, and extubation times. We enrolled 20 patients having cardiac surgery via
median sternotomy; 17 patients completed the study. A de-sflurane-based, small-dose
opioid anesthetic was used. Before sternal wire placement, the surgeons performed the parasternal block and
local anesthetic infiltration of
sternotomy and tube sites with either 54 mL of saline placebo or 54 mL of 0.25%
levobupivacaine with 1:400,000
epinephrine. Effects on
pain and respiratory function were studied over 24 h. Patients in the
levobupivacaine group used significantly less
morphine in the first 4 h after surgery (20.8 +/- 6.2 mg versus 33.2 +/- 10.9 mg in the placebo group; P=0.013); they also had better oxygenation at the time of extubation. Four of nine in the placebo group needed rescue
pain medication, versus none of eight in the
levobupivacaine group (P=0.08). Peak serum
levobupivacaine concentrations were below potentially toxic levels in all patients (0.64 +/- 0.43 microg/mL; range, 0.24-1.64 microg/mL). Parasternal block and
local anesthetic infiltration of the
sternotomy wound and mediastinal tube sites with
levobupivacaine can be a useful
analgesic adjunct for patients who are expected to undergo early tracheal extubation after cardiac surgery.