Target-controlled infusion devices: are we missing much?

Excerpt

Total intravenous anesthesia is probably less popular in North America than in other parts of the world, perhaps because of limited access in Canada and the United States to target-controlled infusion (TCI) devices to deliver intravenous drugs, such as propofol and remifentanil. The principle of operation of commercially available TCI devices, such as the Diprifusor^®, (Astra-Zeneca Pharmaceuticals, Macclesfield, UK) is rather simple. The operator selects a target plasma concentration of drug (e.g., propofol) that the patient requires for a specified procedure, and the TCI device automatically administers a small bolus loading dose followed by a kinetically driven infusion rate to rapidly attain and then maintain that drug concentration until a new drug concentration is selected.1,2 The TCI device informs the anesthesiologist in real time of the population-based theoretical drug plasma concentration attained and the quantity of drug delivered. It is also possible to set TCI devices to target effect-site concentrations. In this case, the infusion rate takes into account the time lag between the plasma and the site of action (e.g., the brain in the case of hypnotics and opioids). In the United States, the Food and Drug Administration did not deem TCI devices sufficiently advantageous in anesthesia to approve their commercial use,3 and the devices are also not currently available in Canada. Are we being deprived of a truly useful tool to improve delivery of intravenous anesthetics, or are these devices merely gadgets that are useful in the research arena but much less so in the clinical setting? …