Thoracic para vertebral block in mastectomy: role of adjuvants

ABSTRACT

This study was designed to investigate whether the addition of ketamine or neostigmine to bupivacaine would enhance the quality of intra- and postoperative analgesia for thoracic paravertebral block in breast surgery. 45 patients, scheduled for mastectomy were randomly divided into three equal groups using sealed envelops technique to receive one of the three study drugs. Group B received 2mg.kg[-1] [max 150 mg] bupivacaine 0.5% with epinephrine [2.5 mcg-mI[-1]]. Group K, received bupivacaine as group B plus Ketamine 0.5mg.kg[-1] and Group N received bupivacaine as group B plus Neostigmine 2 mcg.kg[-1]. All patients received midazolam premedication 5-10 mg orally 45 min before surgery and 1 mg IV Granisetron [Kytril] as prophylactic anti-emetic. Thoracic Para-vertebral Block [TPVB] was applied at levels of 1st [1/3 of the dose] and 4[th] [2/3of the dose] thoracic vertebra. All patients received general anesthesia with LMA after induction with propofol 2-3 mg/kg, and patients were kept spontaneously breathing. All patients received 75mg Diclofenac IV infusion over 30 min and Ranitidine 50 mg IV. Intra-operative rescue analgesia was fentanyl 1-2 micro g.kg[-1] as required. In Post Anesthesia Care Unit [PACU], fentanyl 0.25-0.50 mcg.kg[-1] IV as a rescue medication, every 10 minutes as needed to control postoperative pain. Postoperative patient controlled fentanyl analgesia [PCA] was used. Heart rate [HR] and Mean Blood Pressure [MBP] were measured pre-operatively [baseline], 30 min after incision, on admission to Post Anesthesia Care Unit [PACU], and on discharge from PACU [2 hours postoperatively]. Postoperative Pain evaluated by Numerical Rating Scale [NRS] was assessed on admission to PACU, on discharge from PACU and every 2 hours postoperatively for 24 hours. Intraoperative fentanyl consumption and 24 hour postoperatively was recorded patient satisfaction was evaluated using a 5- points verbal score. Demographic and clinical characteristics were comparable in the study groups. There was significant decrease in MBP in group B compared to the base line, while there were insignificant changes in MBP in all groups during the rest of measured time interval. There were insignificant changes in HR in all groups during the study period. There was significant increase in the total amount of ephedrine in group B compared to groups K and N. A similar small number of TPVB patients in each group required intraoperative fentanyl suggesting inadequate or block failure. The mean 24 hour rescue fentanyl consumption was significantly decreased in Group K and Group N Versus Group B. Pain scores were significantly reduced in groups K and N compared to group B. There were no incidence of nausea or vomiting occurred during the study period. No patient in the study groups experienced hypotension, hypertension or bradycardia at any measured time interval postoperatively. Overall, patient satisfaction was significantly higher in groups K and N versus Group B. Addition of ketamine or neostigmine to bupivacaine in paravertebral block would enhance the quality of intra- and postoperative analgesia for mastectomy surgery with excellent patient satisfaction