Editorial [Hot Topic: Sedation and Analgesia in Post-Anesthesia Intensive Care Unit (Guest Editors: F. Cavaliere and R. Proietti)]

It has been with great pleasure that we have accepted the task of editing the hot topic "Sedation and analgesia in Post-Anesthesia Intensive Care Units" in the current issue of Current Drug Targets. In comparison with the more general subject of sedation and analgesia in generic intensive care units (ICUs), this topic has relevant peculiarities and has been characterized in the previous years by many important changes. Achieving a good postoperative analgesia is a key point to assure patient's well-being and to attenuate nervous and hormonal changes following surgery. On the other hand, analgesic drugs may cause complications that negatively affect patient's clinical course and worsen his/her judgment on hospital staying. Increased bleeding caused by NSAIDs, occurrence of PONV syndrome and delayed recovery of intestinal peristalsis caused by opioids are typical examples of collateral effects related to analgesic therapy. In the previous years, new drugs like anti COX-2 agents, have become available that may cause less complications than older ones; ketamine, an old drug nearly abandoned in clinical practice, has been rediscovered at subanesthetic dosages in order to decrease opioid requirement in the postoperative period; and finally, new routes of administration have been introduced to make safer and easier selfadministration of opioids by the patient. Short-term sedation is used in Post-Anesthesia Care Units (PACUs), when patients are transferred from the operation theatre under general anesthesia and in mechanical ventilation, in order to achieve a more smooth awakening after correction of circulatory, respiratory, and thermal derangements. Delayed awakening from anesthesia may be useful in case of prolonged or highly invasive surgery, but also in compromised patients affected by severe respiratory or circulatory diseases. In these cases, short-acting drugs are preferred in order to facilitate patient awakening and weaning from mechanical ventilation; often, infusions of the drugs employed during general anesthesia may be continued, provided that dosages are decreased consistently with the absence of surgical stimuli. Interactions with drugs administered during anesthesia should be considered; for instance, residual muscle paralysis may initially prevent the application of sedation scores and abrupt interruption of high-dosage remifentanil infusion may cause dangerous hypertensive crisis. Long-term sedation may be required in case of persistent circulatory instability, failure of weaning from mechanical ventilation, sepsis, or severe abdominal hypertension. Postoperative agitation and delirium are frequently observed in PACUs, particularly in elderly patients and following certain kinds of surgery, like hip surgery. Although the incidence of delirium may be even higher during long term sedation in general ICUs, postoperative delirium is particularly harmful because it may negatively affect morbility, mortality, and functional recovery of patients that undergo elective surgery. New approaches on this topic include environmental interventions, pharmacological treatment aimed at preserving the sleep-awake cycle, and the use of new atypical antipsychotics. We sincerely thank each author for the time and effort spent to prepare their contribution to the manuscript and hope that this CDT hot topic on "Sedation and Analgesia in PostAnesthesia Care Units" may be useful to the readers dealing with the problems of perioperative period.