The effects of incisional bupivacaine on postoperative narcotic requirements, oxygen saturation and length of stay in the post-anesthesia care unit.

Abstract

We compared postoperative pain and narcotic requirements, oxygen saturation (SaO2) and length of stay in the post-anesthesia care unit (PACU) in patients who received 30 ml of either 0.25% bupivacaine (B) or saline placebo (S) infiltrated into the operative incision. Twenty ASA I-III patients undergoing abdominal surgery were studied in a double-blinded randomized prospective trial. Study and control groups were not different in patient age, procedure, intra-operative narcotics administered or preoperative SaO2. In the PACU, patients receiving B had significantly lower analog pain scores (6.0 vs 8.3, P = 0.02). They had lower respiratory rates (15.6 b/min vs 19.1, P = to 0.02), required significantly less narcotic (4.5 mg morphine sulphate vs 11.0, P = to 0.03) and were discharged from the PACU almost an hour sooner than patients receiving S (P = 0.02). Patients receiving B had significantly higher minimum SaO2 than those receiving S (93.3% vs 89.9, P = 0.04). Discharge pain scores, SaO2 and respiratory rates were not significantly different between B and S groups. Finally, mean requirements for narcotics for the first 24 h were reduced by approximately 30% (from 406.9 mg meperidine to 255.5 mg, P = 0.006). This study demonstrates that infiltration of a long-acting local anesthetic lowers initial pain scores and requirements for narcotics in the PACU. The effect can be seen for at least the first 24 h. A lower requirement for postoperative narcotics is accompanished by faster wake-up, more alert patients, and, most importantly, higher SaO2 and shorter PACU stay. This may have a significant effect on pulmonary morbidity following abdominal operations.