Incidence of recall, nightmares, and hallucinations during analgosedation in intensive care

Abstract

Objective: To define the incidence of recall and dreams during analgosedation in critically ill patients.

Design: Prospective clinical study.

Setting: Anaesthesiological intensive care unit (ICU) in a university hospital.

Patients and participants: Two hundred and eighty-nine critically ill patients, who either arrived intubated and sedated at the ICU or required intubation, mechanical ventilation, and sedation during their ICU stay.

Interventions: none.

Measurements and results: The patients were interviewed 48-72 h after discharge from the ICU. By a structured interview they were asked whether they recalled any event before they had regained consciousness at the ICU. Moreover they were asked for dreams. Descriptive statistics: 64.7% of all patients did not recall any event, before they regained consciousness. However, 17% ( n=49) of all patients indicated that they remembered the tracheal tube or being on the ventilator, before they woke up. Some patients (21.1%) reported dreams or dreamlike sensations. Some patients (9.3%) recalled nightmares, while 6.6% reported hallucinations.

Conclusions: Critically ill patients reported a high incidence of recall for unpleasant events, which they thought to have taken place before they regained consciousness. The patients, who stayed longer than 24 h at the ICU, indicated vivid memory for nightmares and hallucinations. Further studies are suggested to evaluate: 1) whether there is an impact of the present findings on outcome; and 2) whether clinical scores for sedation or neurophysiological monitoring help to define the exact time, when recall happens, in order to guide therapeutic intervention.