title: Clonidine as an analgesic adjuvant to continuous paravertebral bupivacaine for post-thoracotomy pain.
abstract: We prospectively evaluated the effect of clonidine as an adjuvant to bupivacaine for continuous paravertebral intercostal nerve block, measuring pain and sedation scores and pulmonary function tests. Thirty patients scheduled to undergo thoracotomy were randomized to receive either a bolus of 0.125% bupivacaine 2 mg/kg (group BUP) or 0.125% bupivacaine 2 mg/kg with clonidine 2 microg/kg (group BUP+CLO), followed by an infusion of 0.125% bupivacaine at 0.5 mg/kg/h, or 0.125% bupivacaine at 0.5 mg/kg/h with clonidine at 2 microg/kg/h, in respective groups, through a paravertebral intercostal catheter. Haemodynamic parameters, pain and sedation scores and pulmonary function tests were recorded at 6, 12, 24 and 48 hours after arrival in postoperative care unit. There were significantly lower pain scores at rest and on coughing in group BUP+CLO compared with group BUP (P <0.01). Multiple comparisons revealed a significant reduction in pain score at each time point (P<0.01), except at 12h to 24h, in group BUP+CLO. Sedation scores were significantly higher in group BUP+CLO compared with group BUP at each time point (all P<0.01). There was a linear effect of time on sedation score in group BUP whereas in group BUP+CLO, the effect was quadratic. Patients in the clonidine group had a higher incidence of hypotension (P < 0.01). There was no significant difference in pulmonary function between the groups. We conclude that using clonidine as an adjunct to bupivacaine for continuous paravertebral intercostal nerve block improves pain relief after thoracotomy, but hypotension and sedation are adverse effects interfering with its clinical application.
authors.affiliation: Department of Anaesthesiology, Institute Rotary Cancer Hospital, All India Institute of Medical Sciences, New Delhi.
authors.forename: S
authors.initials: S
authors.lastname: Bhatnagar
authors.forename: S
authors.initials: S
authors.lastname: Mishra
authors.forename: S
authors.initials: S
authors.lastname: Madhurima
authors.forename: M
authors.initials: M
authors.lastname: Gurjar
authors.forename: A S
authors.initials: AS
authors.lastname: Mondal
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000009:adverse effects / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D002045:Bupivacaine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D003000:Clonidine / Q000009:adverse effects / Q000627:therapeutic use*; D003371:Cough / Q000150:complications; D004311:Double-Blind Method; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006993:Hypnotics and Sedatives; D007278:Injections, Spinal; D007367:Intercostal Nerves; D008297:Male; D008875:Middle Aged; D009407:Nerve Block; D010147:Pain Measurement; D010149:Postoperative Pain / Q000188:drug therapy* / Q000209:etiology; D011446:Prospective Studies; D012129:Respiratory Function Tests; D013908:Thoracotomy
chemical_list: D000316:Adrenergic alpha-Agonists; D000779:Anesthetics, Local; D006993:Hypnotics and Sedatives; D003000:Clonidine; D002045:Bupivacaine