We thank Van Elstraete et al.  for their interesting remarks concerning our article. 1We agree that a continuous infusion of low-dose ketamine during patient controlled analgesia with morphine may be better than a patient-controlled approach alone. However, when applied to the clinical settings, problems arise. At best, an additional electronic pump would be required. This would, however, increase costs. Alternatively, a simple intravenous perfusor may be used. We find this approach less safe in the ward. Furthermore, the addition of another intravenous line and device is inconvenient and reduces patient’s mobility.

Thus, although from a pharmacologic point of view the observation by Van Elstraete et al.  is correct, in our opinion the pure patient-controlled anesthesia approach is more practical. Whether the continuous ketamine infusion is superior to the patient-controlled anesthesia delivery is yet to be demonstrated by a randomized controlled trial.

Sveticic G, Gentilini A, Eichenberger U, Luginbühl M, Curatolo M: Combinations of morphine with ketamine for patient-controlled analgesia: A new optimization method. A nesthesiology 2003; 98: 1195–205