title: The accuracy of timed maximum local anaesthetic dose calculations with an electronic calculator, nomogram, and pen and paper.
abstract: Forty anaesthetists calculated maximum permissible doses of eight local anaesthetic formulations for simulated patients three times with three methods: an electronic calculator; nomogram; and pen and paper. Correct dose calculations with the nomogram (85/120) were more frequent than with the calculator (71/120) or pen and paper (57/120), Bayes Factor 4 and 287, p = 0.01 and p = 0.0003, respectively. The rates of calculations at least 120% the recommended dose with each method were different, Bayes Factor 7.9, p = 0.0007: 14/120 with the calculator; 5/120 with the nomogram; 13/120 with pen and paper. The median (IQR [range]) speed of calculation with pen and paper, 38.0 (25.0-56.3 [5-142]) s, was slower than with the calculator, 24.5 (17.8-37.5 [6-204]) s, p = 0.0001, or nomogram, 23.0 (18.0-29.0 [4-100]) s, p = 1 × 10-7. Local anaesthetic dose calculations with the nomogram were more accurate than with an electronic calculator or pen and paper and were faster than with pen and paper.
authors.affiliation: Betsi Cadwaladr University Health Board, Bangor, Wales.|Bangor University, Bangor, Wales.
authors.forename: J D
authors.initials: JD
authors.lastname: Walker
authors.affiliation: Department of Anaesthesia, University Hospital of Wales, Cardiff, Wales.
authors.forename: N
authors.initials: N
authors.lastname: Williams
authors.affiliation: Abertawe Bro Morgannwg University Health Board, Swansea, Wales.|Swansea University, Swansea, Wales.
authors.forename: D J
authors.initials: DJ
authors.lastname: Williams
mesh_terms: D000772:Anesthesia, Local / Q000706:statistics & numerical data*; D000072080:Anesthesiologists; D000779:Anesthetics, Local / Q000008:administration & dosage*; D001499:Bayes Theorem; D002045:Bupivacaine / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008012:Lidocaine / Q000008:administration & dosage; D049451:Nomograms; D015203:Reproducibility of Results; D012984:Software
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine; D002045:Bupivacaine
keywords: local anaesthetic concentration calculation; local anaesthetic systemic toxicity