CARE--Childhood Awareness and Recall Evaluation

Awareness, or the unwanted recall of intra-operative events occurring during general anesthesia, is a potentially avoidable anesthetic complication that poses the risk for psychological sequelae. While the reported incidence is 0.1-0.2% in adults, this translates to > 20,000 cases of awareness occurring in adults annually in the United States (Ekman, 2004; Myles, 2000; Sandin, 2000; Sebel, 2004; Myles, 2004). Patients who experience recall may subsequently exhibit post-traumatic stress and psychological symptoms (Sebel, 2004; Myles, 2004; Moerman, 1993; Lennmarken, 2002). Furthermore; studies have shown that up to 54% of adult patients worry about the possibility of awareness during surgery (Klafta, 1996). Subsequent to the recent studies on unintended intraoperative awareness and published data on the impact of Bispectral Index in preventing and detecting anesthesia awareness, the Joint Commission on Accreditation of Healthcare Organizations has classified intraoperative awareness as a sentinel event (2004).

Limited data are available regarding the incidence and consequences of awareness in children. Studies which are available have identified a significantly higher incidence of intraoperative recall in children than has been shown in adults. McKie reported an incidence of 5% factual recall in 202 patients aged 7-14 years in 1973 (1973). The incidence of dreaming was reported as 11%. Hobbs, in 1988, reported a 19% incidence of dreaming and no awareness in 120 pediatric patients who received the "Liverpool anesthetic technique" (N20, O2, relaxant). Ranta reported 0.4% awareness in 4800 patients aged 12 years or older, with the youngest patient demonstrating undisputed awareness at 20 years of age (1998). More recently, Lopez et. al., found an 8% incidence of awareness in children 6-16 years of age, with a significant relationship between multiple attempts to secure the airway and the likelihood of awareness (2004). Most recently, a study published in 2005 by Davidson, et. al., found an incidence of 0.8% in 864 children aged 5-12 years of age with general anesthesia as is practiced in Australia. Likely explanations for more frequent awareness in children include altered anesthetic pharmacology in children and differences in the practice of pediatric anesthesia.

Post-operative behavior changes including emergence delirium, general anxiety, nighttime crying, enuresis, separation anxiety and temper tantrums have been described to occur up in to 50% of children undergoing surgery (Kain, 1996). Studies have also shown a correlation between pre-operative anxiety levels of both the child and parents, and may result in a greater risk of emergence delirium and later maladaptive behaviors. These results have not demonstrated a cause-effect relationship (Kain, 2004). Evaluating for intra-operative awareness or unwanted recall of intra-operative events with or without depth of anesthesia monitoring, may add to the knowledge base for causal factors in postoperative maladaptive behavior changes in the pediatric population.

The JCAHO Sentinel Event Alert, Issue 32, dated October 6, 2004, describes recommendations for health care organizations which perform procedures under general anesthesia, for the prevention and detection of intra-operative awareness. Specific recommendations include: identification of patients who are at higher risk for intraoperative awareness, appropriate follow-up of all patients, including children, who have undergone general anesthesia, and identification, management and, if appropriate, referral of patients who have experienced awareness.

Since little data exists on the incidence and identification of intra-operative awareness in children, this multi-center, prospective, observational, cohort evaluation is being conducted to describe and evaluate the incidence of awareness during routine general anesthetic practice in children. Following IRB approved informed consent (and assent as appropriate), children will sequentially be enrolled to participate in the study. Participating institutions will share de-identified data of enrolled pediatric patients undergoing general anesthesia. Each center will collect and maintain patient data in compliance with all privacy and institutional guidelines.