Opioid or propofol: what kind of drug for what kind of sedation? Manual dosing or target-controlled infusion?

Johan Raeder, MD, PhD Although propofol is usually considered to be a better sedative in terms of reliable effect and lower incidence of side effects compared with the opioids, the article by Lallo et al. in the present issue of Anesthesia & Analgesia challenges this opinion. They found better patient cooperation and fewer airway and ventilatory problems with spontaneous ventilation for remifentanil when compared with propofol during awake fiberoptic intubation. The pain scores were similar with the two drugs but less recall was reported after propofol. This raises some interesting questions as to the dedicated use of an anesthetic drug to provide sedation for a wide variety of procedures and indications: What do we mean by sedation? What aspects of sedation do we really aim for in different situations? Will target-controlled infusions (TCI) help us provide more precise balance between the sedative effect and unwanted side effects? Sedation is a term used to describe a drug-induced state of calm, restfulness or drowsiness. In more clinical terms we may attribute the sleepy and undisturbed appearance to effect components, such as: anxiolysis, hypnosis, analgesia, and amnesia. Sedation is provided to improve the perceived quality of a variety of diagnostic or therapeutic procedures for the patients. Usually, when we observe a patient to be sleepy and quiet during sedation, we assume that the patient is doing well. However, the history of droperidol premedication has taught us that this may be misleading. High sedative doses of droperidol were extensively used for premedication about 30–40 yr ago because the patients became sleepy and looked calm. However, many patients could describe feeling terrible and horrified. Thus, the first lesson to learn is to ask and anticipate what drug quality the patients will need for their well being during a specific procedure. The answer will have to do both with the patients themselves and the nature of the procedure they will be subjected to. Some patients will like to be asleep, as continuous sleep will take away conscious input and memory of anything frightening or unpleasant during the procedure. The sleep should be pleasant, without nightmares, bad dreams or unpleasant recovery. Other patients will prefer to be awake and have some control, while wanting the benefits provided by an anxiolytic drug. The attitude towards amnesic effect, being awake and even communicate with no recall, is mixed. Some patients will think this is frightening because they want to remember and control what they said and how they behaved, while some would actually like to know what is going on with the procedure, for instance, by looking at the monitor during a knee arthroscopy. Others will think amnesia is a good idea in order to ensure absence of bad memories afterwards. For the physician in charge, an amnesic effect may be useful if the patient experiences unpleasant inputs, but problematic if the surgeon likes to educate or inform the patient during the procedure or shortly thereafter. An additional aspect of sedation is introduced when the patient is subjected to significant nociceptive simulation or pain during the procedure. In this case, an anxiolytic or hypnotic effect may help to smooth the From the Medical Faculty, University of Oslo, and Department of Anesthesia, Ullevaal University Hospital, Oslo, Norway. Accepted for publication November 11, 2008. The author did not receive any financial support for writing this editorial and has no commercial relation with any drug companies involved with the topics of the editorial. Address correspondence and reprint requests to Johan Raeder, Department of Anesthesia, Ullevaal University Hospital, N-0407 Oslo, Norway. Address e-mail to johan.rader@medisin.uio. no. Copyright © 2009 International Anesthesia Research Society DOI: 10.1213/ane.0b013e3181954146