LAUSR

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.