1. Age- and therapy-related effects on morphine requirements and plasma concentrations of morphine and its metabolites in postoperative infants 
N.J. Bouwmeester, J.N. van den Anker, W.C.J. Hop, K.J.S. Anand, D Tibboel 
British Journal of Anaesthesia 
Volume 90, Issue 5, Pages (May 2003)
DOI: /bja/aeg121
Copyright © 2003 British Journal of Anaesthesia Terms and Conditions

2. Fig 1
Percentages of patients in the four age groups (I 0–4 weeks, II ≥4–26 weeks, III ≥26–52 weeks, IV ≥1–3 yr) needing additional morphine during the first 24 h after surgery.
British Journal of Anaesthesia  , DOI: ( /bja/aeg121)
Copyright © 2003 British Journal of Anaesthesia Terms and Conditions

3. Fig 2
(a) Morphine, (b) morphine-3-glucuronide (M3G) and (c) morphine-6-glucuronide (M6G) plasma concentrations (median) in the four age groups (I 0–4 weeks, II ≥4–26 weeks, III ≥26–52 weeks, IV ≥1–3 yr) at 6, 12 and 24 h after surgery. CM=continuous morphine, IM=intermittent morphine.
British Journal of Anaesthesia  , DOI: ( /bja/aeg121)
Copyright © 2003 British Journal of Anaesthesia Terms and Conditions