Thoracic epidural for post-thoracotomy and thoracomyoplasty pain: a comparative study of three concentrations of fentanyl with plain ropivacaine

ABSTRACT

Optimum pain relief after thoracotomy is essential to reduce atelectasis and postoperative pneumonias. The aim of this prospective, double blind, randomised controlled trial was to compare the analgesic and adverse effects of three concentrations of fentanyl with 0.2% ropivacaine in thoracic epidural in patients undergoing thoracotomy and thoracomyolpasty. After getting approval from Ethical Committee, this study was performed in 60 patients of either sex, aged 18-60 years, American Society of Anaesthesiology [ASA] grade I to III. Informed consent was taken from all of the patients, who were recruited and divided into three groups of 20 patients in each group. Patients scheduled for elective thoracotomy surgery were enrolled in the study. Patients with preexisting motor and sensory deficit, addicted to hypnosedative drugs, on chronic opioid or analgesic therapy, sensitive to local anaesthetic or study medication, or having contraindications to regional anesthesia were excluded from this study. In patients, with whom communication difficulties prevented reliable assessment, were also excluded. Patients received either 2.5micro g/ml [Group I], 5.0micro g/ml [Group II] or 7.5micro g/ml of fentanyl [Group III] respectively, with ropivacaine 0.2% via thoracic epidural. Postoperatively, pain at rest, on coughing and with ambulation was assessed using a visual analogue scale [VAS] and observer verbal ranking score [OVRS] at 2, 6, 12 and 24 hours. Sedation scores were also noted. Adverse effects were simultaneously assessed. There was no significant difference in the baseline characteristics between the three groups. The number of patients with episodes of unsatisfactory pain relief, i.e. a VAS scores >40 and OVRS >2, at each of the four assessments postoperatively, was higher in Group I than with Group II or Group III [p < 0.05]. In Group III, four [20%] patients had a sedation score >3 compared with one [5%] in Group II. No patient in Group I had a sedation score >3 [p < 0.05]. In addition, all patients experienced pruritus in Group I compared with 10% and 5% in Group II and Group I respectively. 30% of the patients had emetic symptoms in Group III, compared to 20% and 5% in Group II and Group I respectively [p < 05]. We conclude that a thoracic epidural bolus of 10 ml ropivacaine 0.2% with fentanyl 5.0 micro g/ml provides the optimal balance between pain relief and sedation