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 1
is surprising. Our own and others experiences have demonstrated superior dynamic pain relief during EDA versus
intravenous PCA, 2,3
also after abdominal aortic surgery. 4
The 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. 5
The additional use of a background infusion during intravenous PCA increases the risk of respiratory depression about five-fold. 3
Therefore background infusion during intravenous PCA is not recommended for routine postoperative analgesia on the ward, especially in patients with higher risk. 6
Increased 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?
Jürgen Jage, M.D. Ph.D.