Continuous Local Infusion of Bupivacaine with ON-Q Pump System for Pain Management after Median Sternotomy

Background: Postoperative pain remains as a challenging case despite improvement of analgesic techniques. It may also increase the rate of morbidity and even mortality. Local anesthesia may decrease the consumption of opioids and its potential side effects. This study was aimed to show the role of local anesthesia in post-sternotomy pain. Methods: This prospective randomized clinical trial includes 40 candidates for elective coronary artery bypass graft (CABG) surgery. Patients with diabetic mellitus and other major co-morbidities were excluded. In group A (20 patiens) Bupivacaine 0.25% was continuously infused into subcutaneous tissue using the ON-Q system (I-flow Corporation, Lake Firest CA, USA) (2ml/h for 72h). Group B patients did not receive local anesthetics. The intensity of pain in was measured using Visual Analogue Scale (0-10). Need for narcotics or other analgesics, hemodynamic and arterial blood gas profiles were also recorded. Results: Both groups were similar regarding age, sex, body mass index, smoking and drug addiction and operative characteristics. The mean visual analogue scale (VAS) was significantly lower in G.A than G.B (2.1+/-1.7 versus 4.3+/- 2.7) (P=0.005). Narcotics requirement in G.A had decreased 25% compared to G.B (P= 0.041) but the mean doses of opioids consumption had no significant difference in two groups. Most of the patients in G.A (85%) were fully satisfied from his pain control, while this rate was only 45% in G.B (P= 0.029). Regarding other post- operative complications, both groups were identical and no significant difference was observed. Days of stay in hospital was reduced 1.4 days in average which is not significant (P=0.06). Drug addicts required higher doses of narcotics. Conclusion: Continuous local infusion of Bupivacain with ON-Q pump system can be useful and safe for pain management after median sternotomies. Bupivacaine not only reduces the pain intensty, but also reduces the consumption of opioids and other analgesics when compared to the control group. It also seems that this method may reduce the length of hospitalization and hence the hospital charges.