Premium
A nomogram for calculating the maximum dose of local anaesthetic
Author(s) -
Williams D. J.,
Walker J. D.
Publication year - 2014
Publication title -
anaesthesia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.839
H-Index - 117
eISSN - 1365-2044
pISSN - 0003-2409
DOI - 10.1111/anae.12679
Subject(s) - nomogram , medicine , calculator , local anaesthetic , volume (thermodynamics) , correlation coefficient , limits of agreement , nuclear medicine , anesthesia , statistics , mathematics , computer science , physics , quantum mechanics , operating system
Summary Toxic dose limits (mg.kg −1 ) for local anaesthetics based on body weight are well‐established, but calculation of the maximum safe volume (ml) of a given agent and formulation is complex, and frequently results in errors. We therefore developed a nomogram to perform this calculation. We compared the performance of the nomogram with a spreadsheet and a general purpose calculator using simulated clinical data. Bland‐Altman analysis showed close agreement between the nomogram and spreadsheet, with bias of −0.07 ml and limits of agreement of −0.38 to +0.24 ml (correlation coefficient r 2 = 0.9980; p < 0.001). The nomogram produced fewer and smaller errors compared with the calculator. Our nomogram calculates the maximum safe volume (ml) of local anaesthetic to a clinically acceptable degree of accuracy. It facilitates rapid cross‐checking of dosage calculations performed by electronic or other means at negligible cost, and can potentially reduce the incidence of local anaesthetic toxicity.