Reactions 1275 - 24 Oct 2009

SBupivacaine

Heart block in an elderly patient: case reportA 78-year-old woman with chronic liver disease

experienced a third-degree heart block during an infusionof bupivacaine following total knee arthroplasty.

Prior to surgery, the woman underwent femoral nerveblock with 30mL of 0.50% bupivacaine and the catheterwas left in place. A left total knee arthroplasty was carriedout under general anaesthesia without any complicationsand she was transferred to the postoperative care unit. Shethen received an infusion of 0.25% bupivacaine at a rate of8mL/h. Postoperative tests revealed a haematocrit level of34% and decreased levels of calcium and magnesium soshe received IV calcium gluconate and magnesium sulfate.About 6 hours after bupivacaine infusion initiation (9 hoursafter nerve block establishment), she had a HR of38 beats/min. She was alert and oriented, but drowsy.Laboratory tests revealed a haematocrit of 32.5%, an INR of1.6 and an albumin level of 2.8 g/dL. An ECG showed acomplete atrioventricular heart block (third degree). Shewas diagnosed with asymptomatic complete heart block.

The woman’s femoral nerve catheter was discontinuedand she was transferred to the coronary care unit. Her sinusrhythm normalised within 6 hours of bupivacaine cessationand she was transferred from the coronary care unit48 hours later. She did not experience any further episodesof conduction abnormality, arrhythmia or heart blockduring hospitalisation. On postoperative day 4, she wasdischarged without complications. She was followed up asan outpatient at a cardiology clinic, but her work up wasnegative so she was discharged.

Author comment: "[Bupivacaine] is . . . metabolized bythe p450 enzyme pathway in the liver, specifically CYP3A. . .[T]his enzyme pathway is impaired by 25% to 50% in patientswith advanced liver disease. While our patient did not haveadvanced liver disease (Child-Pugh class A), it is probable thatshe had some impairment of this metabolic pathway. Thelow serum albumin level and probable metabolic dysfunctionlikely led to a transient increase in the serum concentration offree bupivacaine."Hay DC, et al. Third-degree heart block associated with bupivacaine infusionfollowing total knee arthroplasty. A case report. Journal of Bone and Joint Surgery- American Volume 91: 2238-2240, No. 9, Sep 2009 - USA 801154182

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Reactions 24 Oct 2009 No. 12750114-9954/10/1275-0001/$14.95 © 2010 Adis Data Information BV. All rights reserved