Fig. 2. Comparison of (A ) the score on the visual analog pain scale (VAPS; mean ± SD) and (B ) the percentage of patients with pain relief in young (n = 875) and elderly (n = 175) patients. Pain relief is defined as a score on the VAPS of less than 30 mm. NS = not significant. The result of the initial five boluses and the result at the end of morphine titration (end) are shown, but the number of boluses was not limited.