To the Editor:—

Congratulations to the authors for this excellent study. Some comments: The equal analgesic effectiveness in both epidural analgesia (EDA) and intravenous patient-controlled analgesia (PCA) in this study 1is surprising. Our own and others experiences have demonstrated superior dynamic pain relief during EDA versus  intravenous PCA, 2,3also after abdominal aortic surgery. 4The authors have improved analgesic effectiveness of intravenous PCA by a background infusion, with an initial dosage of 80 μg/h fentanyl plus 40 μg on demand. Calculations result in a possible cumulative fentanyl consumption of approximately 2 mg/24 h. The intravenous infusion of fentanyl (75 μ g/h) induces ventilatory disturbances, and in some patients severe respiratory insufficiency or apnea. 5The additional use of a background infusion during intravenous PCA increases the risk of respiratory depression about five-fold. 3Therefore background infusion during intravenous PCA is not recommended for routine postoperative analgesia on the ward, especially in patients with higher risk. 6Increased dosages of opioids may induce sleep disturbances, fatigue, and disability 7, which all are undesired side effects after high-risk surgery. These doubts do not refer to special study conditions, but to routine analgesia on the ward.

Two questions: how high was the fentanyl consumption during intravenous PCA and EDA at days 1, 2, and 3? Did side effects from fentanyl occur?

Norris EJ, Beattie C, Perler BA, Martinez EA, Meinert CL, Anderson GF, Grass JA, Sakima NT, Gorman R, Achuff SC, Martin BK, Minken SL, Williams G, Traystman RJ: Double-masked randomized trial comparing alternate combinations of intraoperative anesthesia and postoperative analgesia in abdominal aortic surgery. A nesthesiology 2001; 95: 1054–67
Brodner G, Mertes N, Buerkle H, Marcus MAE, Van Aken H: Acute pain management: Analysis, implications and consequences after prospective experience with 6349 surgical patients. Eur J Anaesthesiol 2000; 17: 566–75
Schug SA, Torrie JJ: Safety assessment of postoperative pain management by an acute pain service. Pain 1993; 55: 387–91
Boylan JF, Katz J, Kavanagh BP, Klinck JR, Cheng DC, DeMajo WC, Walker PM, Johnston KW, Sandler AN: Epidural bupivacaine-morphine analgesia versus patient-controlled analgesia following abdominal aortic surgery. A nesthesiology 1998; 89: 585–93
Salomäki TE, Laitinen JO, Nuutinen LS: A randomized double-blind comparison of epidural versus intravenous fentanyl infusion for analgesia after thoracotomy. A nesthesiology 1991; 75: 790–5
Macintyre PE: Safety and efficacy of patient-controlled analgesia. Br J Anaesth 2001; 87: 36–46
Rosenberg-Adamsen S, Kehlet H, Dodds C, Rosenberg J: Postoperative sleep-disturbances-mechanisms and clinical implications. Br J Anaesth 1996; 76: 552–9