Reactions 1351 - 14 May 2011

SBupivacaine/prilocaine

Methaemoglobinaemia: case reportA 19-year-old woman developed methaemoglobinaemia

after local anaesthesia with prilocaine and bupivacaine.The woman underwent outpatient surgery for a foot

deformity, and received 2% prilocaine 2 × 26mL and 0.5%bupivacaine 2 × 12mL [routes not stated]. Hypoxaemiaemerged toward the end of the 3-hour surgery, andpersisted despite administration of high-dose oxygen. Toxicmethaemoglobinaemia was suspected.

The woman received ascorbic acid andmethylthioninium chloride, and was transferred to ahospital. On admission, central cyanosis and light-gray skintone were evident, and she reported headache and malaise.Her HR and RR were mildly elevated, and her blood had adark red to brown hue. Laboratory investigations revealedthe following: WBC count 15.23 × 109/L, platelet count218 × 109/L, CK 1462 U/L and AST 45 U/L. Arterial blood gasanalysis showed a pH of 7.6, a pO2 of 280mm Hg, a pCO2

of 21.1mm Hg, a bicarbonate level of 26.1 mmol/L, a baseexcess of 1.9 mmol/L and a methaemoglobin level of 24%.She was transferred to an ICU and received oxygen via afacemask. Hourly blood gas analysis showed graduallyincreasing oxygenation, and improvement of her headacheand nausea within the first few hours. Four hours afteradmission, she had a pH of 7.43 and an oxygen saturationof 96% on 5 L/min of oxygen; her methaemoglobin levelhad decreased to 14.7%. She was transferred to a ward thefollowing morning. She subsequently developed mildhaemolysis (haemoglobin 11.7 g/dL, elevated indirectbilirubin) with normal G6PDH activity, which wasattributed to methylthioninium chloride. Hermethaemoglobin level had normalised 14 hours fromadmission, and she was in good overall condition ondischarge the next day.

Author comment: Toxic methaemoglobinaemia should beconsidered in cases of therapy-resistant hypoxaemia followingadministration of local anaesthesia.Bender P, et al. Toxic methemoglobinemia. Deutsche Medizinische Wochenschrift136: 762-764, No. 15, Jan 2011. Available from: URL: http://dx.doi.org/10.1055/s-0031-1275803 [German] - Germany 803054099

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Reactions 14 May 2011 No. 13510114-9954/10/1351-0001/$14.95 © 2010 Adis Data Information BV. All rights reserved