Drugs for amnesia in the ICU

Abstract

OBJECTIVE: This review focuses on how patients' recall of their stay in the ICU can be modified pharmacologically. DATA SOURCES: Computerized MEDLINE and PAPERCHASE searches of English- and foreign-language published research from 1966 to 1995, bibliographies, pharmaceutical and personal files, and conference abstract reports. STUDY SELECTION: All abstracts from uncontrolled and controlled clinical trials were reviewed. DATA EXTRACTION: Study design, population, results, and safety information were retained. Efficacy conclusions were drawn from controlled trials. DATA SYNTHESIS: Patients without cerebral injury may recall mental and physical discomfort during their stay in the ICU. All benzodiazepines produce amnestic effects, but the short duration of action, lack of long-acting metabolites, and potent amnestic effects make lorazepam and midazolam preferable in this setting. Infusions of propofol for conscious sedation produce concentrations below those required for consistent amnesia. Opioids generally do not produce amnesia; however, end-organ failure and use of high doses of opioids may increase plasma concentrations to levels that produce impairment of learning and various degrees of amnesia. High infusion rates of ketamine may be required for satisfactory amnesia and pain control (with coadministration of benzodiazepine). Barbiturates and haloperidol do not impair memory in patients who are not critically ill. Antihistamines and anticholinergics that do not penetrate the central nervous system do not produce amnesia. Flumazenil may induce recall. CONCLUSIONS: Patients may remember their stay in the ICU, depending on the type of injury and the drug therapy. Of the drugs presented, benzodiazepines most reliably provide anterograde amnesia, whereas ketamine and propofol exhibit dose-dependent effects on memory.

Stressful experiences in relation to depth of sedation in mechanically ventilated patients

“…During mechanical ventilation, sedation has become an important component of the treatment, and intubated patients are frequently treated with sedatives (Young et al, 2000;Hurford, 2002;Izurieta and Rabatin, 2002). However, knowledge about the impact of pharmacological sedation on severely ill patients' memory and perception of discomfort is sparse (Wagner et al, 1997;Jones et al, 2000a;Capuzzo et al, 2001;Clifford and Buchman, 2002;Rundshagen et al, 2002), and no studies have focused on the relationship between mechanically ventilated patients' stressful experiences and the use of sedatives, including the depth of sedation.…”

“…In critically ill patients, adequate sedation cannot be achieved without adequate analgesia (Walder and Tramer, 2004), and a strategy that strives on assuring adequate analgesia will often reduce the need for sedatives in many mechanically ventilated patients (Kress et al , 2002) as pain and anxiety are inextricably linked. Furthermore, commonly used analgesic agents such as opioids contribute to the sedative effect, and can, if administered in high doses, produce deep sedation or anaesthesia by their own (Wagner et al , 1997; Hurford, 2002; Walder and Tramer, 2004). Therefore, intensive care sedation is linked to the associated use of analgesia.…”

“…Therefore, assessment of sedation by means of depth of sedation is essential, and the use of a sedation score is the most common and still the best method available for evaluating the level of sedation in critically ill patients (Devlin et al , 2001; Jacobi et al , 2002; Watson and Kane‐Gill, 2004). Since sedative drugs commonly used in the ICU have amnesic, hypnotic and anxiolytic properties and by that affect patients’ level of wakefulness and consciousness (Wagner et al , 1997; Walder and Tramer, 2004), the effect on patients’ memory and perception of discomfort in the ICU might vary according to patients’ level of sedation. The depth of sedation is consequently an important concept and may have an impact on patients’ perception of stressful experiences in the ICU.…”

Memory in relation to depth of sedation in adult mechanically ventilated intensive care patients

“…Adapted to the individual needs and the current situation, adequate administration of SAAs increases comfort, reduces stress response and facilitates diagnostic and therapeutic procedures [13,14]. Although there are numerous reasons for disturbed memory and amnesia in critically ill patients [15,16,17], the amnestic properties of SAAs make the impact on memory evident [18]. A dose-dependent responsiveness has been suggested between commonly administered sedatives in the ICU and the formation and retention of memory [19,20].…”

Use of Sedative Medications in the Intensive Care Unit

“…[9][10][11][12] It also features anterograde amnestic qualities; unfortunately, at the lower doses commonly used in the ICU, the extent of achievable amnesia with propofol is not reliable or at the level of the benzodiazepines. 13 Similar to the benzodiazepines, propofol has no analgesic activity. Propofol has even been used with some success to manage alcohol withdrawal.…”