Bupivacaine combined with morphine for patient-controlled epidural analgesia after thoracotomy: high volume and low concentration vs. low volume and high concentration

M. Tunç, O. Küçük, G. Ülger, M.Ö. Cirik, R. Baldemir, O. Kaybal, H. Sazak

Department of Anesthesiology and Reanimation, University of Health Sciences, Ankara Atatürk Sanatoryum Training and Research Hospital, Ankara, Turkey. drmehtaptunc@yahoo.com

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• Anesthesiology

OBJECTIVE: In this prospective randomized controlled study, we aimed to evaluate the effects of the administration of equal doses of bupivacaine and morphine (BM) at high volume and low concentration (HV-LC) or low volume and high concentration (LV-HC) on the number of drugs consumed, pain scores and side effects.

PATIENTS AND METHODS: We randomized 64 patients who underwent thoracotomy into two groups. Group 1 received a solution prepared with 0.12% bupivacaine and 0.05 mg/cc morphine, administered with a basal infusion rate of 4 cc/h, a 2-cc bolus dose, and a 30-minute lockout time. Group 2 received a solution prepared with 0.48% bupivacaine and 0.2 mg/cc morphine, administered with a basal infusion rate of 1 cc/h, a 0.5-cc bolus dose, and a 30-minute lockout time. We compared patient-controlled epidural analgesia (PCEA) usage doses, pain scores, sensory and motor block, hemodynamic effects, side effects, and patient satisfaction in the postoperative periods.

RESULTS: An increase in drug consumption with PCEA was found in the first 24 hours postoperatively in Group 2 (p<0.05). Resting visual analog scale (VAS) scores were statistically significantly higher at hours 2, 28, 32, 36, 44 and coughing VAS scores were also higher at hours 2 and 20 in Group 2. Heart rates in Group 2 were lower than in Group 1 at hours 16, 24, 44 and 48 (p<0.05). The cephalic spread of the sensory block in Group 1 was more extensive (p<0.05). The groups demonstrated no significant differences regarding side effects and patient satisfaction (p>0.05).

CONCLUSIONS: The HV-LC approach resulted in better analgesia, less drug consumption, and greater cephalic spread of sensory block than the LV-HC approach. Both applications were effective and safe in terms of analgesia and side effects.

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