We thank Drs Holmes, Jefferson and Ball for their interest in the AAGBI’s guidelines for the management of severe local anaesthetic toxicity . It is correctly pointed out that the recommendations have changed. In 2004, there had been no reported uses of lipid rescue in humans. When Dr Weinberg recommended beginning treatment with a bolus of 1 ml.kg−1 of 20% lipid emulsion, the figure was derived from animal experiments alone . The first human case reports appeared in 2006 [3, 4]. The AAGBI Working Party on the Management of Severe Local Anaesthetic Toxicity (which included Dr Weinberg) considered all the evidence available in 2007, and increased the recommended bolus to 1.5 ml.kg−1 because larger doses had worked in humans, restoring cardiac output, and seemed to cause no harm.
Dr Holmes et al. remind us that few volumetric infusion pumps are designed to cope with infusion rates > 1 l.h−1 and that the clinical situations created by local anaesthetic toxicity are often not those conducive to the rapid and accurate preparation and use of infusion pumps or syringe drivers. This is why we presented both the infusion rates in millilitre per kilogram and also an abbreviated and simplified protocol based on a 70-kg patient: the bulleted points in italic type in this excerpt from the laminated guideline below.
Treatment of cardiac arrest with lipid emulsion: (approximate doses are given in italics for a 70-kg patient)
• Give an intravenous bolus injection of Intralipid® 20% 1.5 ml.kg−1 over 1 min
• Give a bolus of 100 ml
• Continue CPR
• Start an intravenous infusion of Intralipid® 20% at 0.25 ml.kg−1.min−1
• Give at a rate of 400 ml over20 min
• Repeat the bolus injection twice at 5 min intervals if an adequate circulation has not been restored
• Give two further boluses of 100 ml at 5 min intervals
• After another 5 min, increase the rate to 0.5 ml.kg−1.min−1 if an adequate circulation has not been restored
• Give at a rate of 400 ml over10 min
• Continue infusion until a stable and adequate circulation has been restored
We hope to have the opportunity to review the guidelines this year. In doing so, the Working Party will consider comments from Drs Holmes, Jefferson and Ball and others.