Being awake intermittently during propofol‐induced hypnosis: A study of BIS, explicit and implicit memory

Abstract

The BIS-index decreases with increasing sedation but because of the large individual variations, the real-time BIS-index for the individual subject cannot reliably discriminate wakefulness from unconsciousness during propofol infusion. Propofol causes such profound amnesia that lack of postoperative recall does not assure that episodes of awareness have not occurred during propofol-induced hypnosis.

A randomized controlled trial of light versus deep propofol sedation for elective outpatient colonoscopy: recall, procedural conditions, and recovery

“…4 Consequently, even 'light' sedation may result in procedural amnesia despite clinical sedation scores showing preserved responsiveness. 5 It is possible, therefore, that the incidence of recall may be equivalent between light and deep sedation protocols. 5,6 Nevertheless, studies are lacking that make a direct comparison between light and deep sedation (using the same drugs) for colonoscopy with an objective measure of sedation depth, a validated assessment of post-procedure cognitive impairment, and measurements of complications and patient satisfaction.…”

“…5 It is possible, therefore, that the incidence of recall may be equivalent between light and deep sedation protocols. 5,6 Nevertheless, studies are lacking that make a direct comparison between light and deep sedation (using the same drugs) for colonoscopy with an objective measure of sedation depth, a validated assessment of post-procedure cognitive impairment, and measurements of complications and patient satisfaction. A lack of direct comparisons such as this impair the ability to advise patients about the advantages and disadvantages of different sedation depths, including the likelihood of procedural recall.…”

Are β-blockers anesthestics?

“…36 Ce n'est pas uniformément applicable à tous les anesthésiques et à toutes les combinaisons médica-menteuses. [37][38][39][40][41] L'usage du BIS pour prédire la profondeur de l'anesthésie avec l'esmolol n'est donc pas nécessairement valide. Ensuite, il y a différents degrés d'anesthésie "inadéquate", allant de la mémoire implicite, en passant par la mémoire explicite, la réali-sation de commandes pendant l'anesthésie, sans souvenir, jusqu'à la conscience et au souvenir réels.…”

“…36 It is not uniformly applicable to all anesthetics and drug combinations. [37][38][39][40][41] The use of BIS to predict the depth of anesthesia in the presence of esmolol therefore is not necessarily valid. Secondly, there are different levels of "inadequate" anesthesia, ranging from implicit memory, explicit memory, obeying commands during anesthesia without recall, to actual awareness and recall.…”

Effect of propofol on local field potential in rat prefrontal cortex during working memory task

“…With the use of propofol there are some research reports about memory dysfunction caused by propofol anesthesia especially in elderly patients [1][2][3]. It remains unclear, however, whether these cognitive or memory changes are due to the effects of propofol.…”