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 μg/mL; range, 0.24–1.64 μg/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.
IMPLICATIONS: Parasternal block combined with local anesthetic infiltration of the sternotomy wound and mediastinal tube sites after cardiac surgery can provide analgesia and reduce morphine requirements in the early postoperative period.
*Department of Anesthesiology, Virginia Mason Medical Center, Seattle, Washington; †Departments of Cardiothoracic Anesthesiology and Cardiothoracic Surgery, Washington University School of Medicine, St. Louis, Missouri; and ‡Department of Cardiac Surgery, Virginia Mason Medical Center, Seattle, Washington
Supported by a grant from Washington University School of Medicine, Department of Anesthesiology, Clinical Research Division (EJ).
Presented in part at the annual meeting of the American Society of Anesthesiologists, October 2003, San Francisco, CA.
Accepted for publication July 2, 2004.
Address correspondence to Susan B. McDonald, MD, Virginia Mason Medical Center, 1100 Ninth Ave., PO Box 900, Mailstop B2-AN, Seattle, WA 98111. Address e-mail to email@example.com. No reprints will be available.