Toward tailored sedation with halogenated anesthetics in the intensive care unit?

SUBSTANTIAL efforts have been made over the past decade to focus more attention on sedation and analgesia management in critically ill patients. Although evidence is accumulating of painful and unpleasant experiences suffered during length of stay in the intensive care unit (ICU) that can affect quality of life, even after discharge, more is also known about the impact of excessive use of sedatives (hypnotic drugs) on patient outcome. Indeed, intravenous hypnotics have been linked to prolonged duration of mechanical ventilation, increased length of ICU stay, increased delirium and altered mental status, ventilator-associated pneumonia, self-extubation, and drug withdrawal syndrome. Thus, ICU physicians face an awkward dilemma in their search for maximal comfort for their patients: to relieve pain and agitation and facilitate mechanical ventilation with unrestricted use of analgesics and sedatives, or to limit sedation and its side effects. In this issue of ANESTHESIOLOGY, Sackey et al. illustrate this dilemma in a case scenario where a 24-h conventional protocol of deep sedation with midazolam, propofol, morphine, and atracurium after major tracheal surgery was followed over the next 24 h by the combined use of isoflurane and clonidine to permit rapid ventilator weaning and shorter wake-up time. The authors advocate that such a tailored sedation and analgesia plan based on each individual’s characteristics should represent the future gold standard in sedation management. They also promote the implementation of halogenated agents in the ICU based on favorable reports of the anesthesia-trained ICU physicians in Sweden as well as on the advantageous short-term elimination of these drugs. This case scenario gives us the opportunity to discuss two major issues: (1) How to optimize sedation and analgesia in the ICU, and (2) what is the place of halogenated agents in the arsenal of ICU sedative agents. Any approach to optimizing sedation and analgesia in the ICU should first consider defining the levels of sedation and analgesia at which the patient should be maintained. Certain patient populations require a deep state of sedation (e.g., those with increased intracranial pressure or with acute respiratory distress syndrome). The use of continuous infusions of sedatives and a neuromuscular blocking agent to keep the patient immobile for several hours after a surgical procedure, which compromises the airway patency, is understandable in the case report presented. The subsequent change in sedative drugs is actually not uncommon because most ICU patients require a change in drug dose or even in the sedation and analgesia strategy during their stay in ICU. However, regardless of the level of pain and sedation deemed as optimum, the paramount point is the ability to assess the pain and sedation in order to adjust drug requirements accordingly or even to justify drug replacement. Only then could a “tailored sedation and analgesia to individual needs” be achieved. Measurements of pain, sedation (vigilance), and delirium can be made with the use of numerous validated and reliable clinical instruments and, occasionally, with the bispectral index in paralyzed patients. Although sedation and pain assessment rates remain below 40% in mechanically ventilated patients, we recently demonstrated an association between pain assessment and reduced number of ventilator days and length of ICU stay; this effect was possibly related to concomitant higher rates of sedation assessment and a reduction in sedative drug dose when pain was assessed. An association was also found between the systematical evaluation of pain and agitation levels and shorter mechanical ventilation duration. Another point to consider in sedation and pain management is the integration of these measurements in standard protocols and sedation strategies. There is large evidence that the administration of sedatives and analgesics, according to these principles, can markedly reduce the duration of mechanical ventilation and the incidence of sedation-related side effects: protocoldirected sedation according to consciousness levels, sedationbased analgesia, daily interruption of sedation, combined