Memory in pediatric patients undergoing conscious sedation for aversive medical procedures

A new view on old problems in paediatric anaesthesia: premedication, postoperative agitation and dosing

PURPOSE OF REVIEW

The aim of this review is to discuss recent developments in paediatric anaesthesia, which have evolved in an undulating fashion.

RECENT FINDINGS

The role and efficacy of pharmacological premedication is reevaluated. The anxiolytic and sedative properties of midazolam and α 2 -agonists have now been defined more precisely. Both classes of drugs have their unique profile, and there is no reason to condemn one or the other. Midazolam is an excellent anxiolytic, whereas dexmedetomidine is superior in the postoperative period and for sedation during diagnostic imaging.A total intravenous technique with propofol is often considered to be the standard for the prevention of emergence agitation; but alternatives do exist, such as a co-medication with dexmedetomidine or opioids. In clinical reality, a multimodal approach may often be advisable.The theoretical basis for propofol dosing has recently been adapted. In contrast to previous beliefs, the context-sensitive half-life of propofol seems to be quite short beyond the first year of life.

SUMMARY

Midazolam and dexmedetomidine are not interchangeable; each compound has its pros and cons. As an anxiolytic drug, midazolam indisputably deserves its place, whereas dexmedetomidine is a better sedative and particularly beneficial in the postoperative period. New data will allow more precise age-adapted dosing of propofol.

Amnesia after Midazolam and Ketamine Sedation in Children: A Secondary Analysis of a Randomized Controlled Trial

The incidence of peri-procedural amnesia following procedural sedation in children is unclear and difficult to determine. This study aimed to apply quantitative and qualitative approaches to better understand amnesia following dental sedation of children. After Institutional Review Board Approval, children scheduled for sedation for dental procedures with oral midazolam (OM), oral midazolam and ketamine (OMK), or intranasal midazolam and ketamine (IMK) were recruited for examination of peri-procedural amnesia. Amnesia during the dental session was assessed using a three-stage method, using identification of pictures and an animal toy. On the day following the sedation, primary caregivers answered two questions about their children’s memory. One week later, the children received a semi-structured interview. Behavior and level of sedation during the dental session were recorded. Quantitative data were analyzed using descriptive statistics and comparison tests. Qualitative data were analyzed using content analysis. Triangulation was used. Thirty-five children (age: 36 to 76 months) participated in the quantitative analysis. Most children showed amnesia for the dental procedure (82.9%, n = 29/35) and remembered receiving the sedation (82.1%, n = 23/28 for oral administration; 59.3%, n = 16/27 for intranasal administration). The occurrence of amnesia for the dental procedure was slightly higher in the oral midazolam group compared with the other groups (44.8%, n = 13/29 for OM, 13.8%, n = 4/29 for OMK, and 41.4%, n = 12/29 for IMK). Twenty-eight children participated in the qualitative approach. The major theme identified was that some children could remember their procedures in detail. We conclude that peri-procedural amnesia of the dental procedure was common following sedation.

What is the level of evidence for the amnestic effects of sedatives in pediatric patients? A systematic review and meta-analyses

Background

Studies have suggested that benzodiazepines are amnestic drug par excellence, but when taken together, what level of evidence do they generate? Are other sedatives as amnestic as benzodiazepines? The aim of this study was to assess the level of scientific evidence for the amnestic effect of sedatives in pediatric patients who undergo health procedures.

Methods

The literature was searched to identify randomized controlled trials that evaluated anterograde and retrograde amnesia in 1-19-year-olds who received sedative drugs during health procedures. Electronic databases, including PubMed, Scopus and Cochrane Library besides clinical trial registries and grey literature were searched. Two independent reviewers performed data extraction and risk of bias assessment using the Cochrane Collaboration's Tool. The meta-analyses were performed by calculating relative risk (RR) to 95% confidence intervals (CI). The quality of the evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation approach.

Results

Fifty-four studies were included (4,168 participants). A higher occurrence of anterograde amnesia was observed when benzodiazepines, the most well-studied sedatives (n = 47), were used than when placebo was used (n = 12) (RR = 3.10; 95% CI: 2.30–4.19, P<0.001; I² = 14%), with a moderate level of evidence. Higher doses of alpha2-adrenergic agonists (clonidine/dexmedetomidine) produced more anterograde amnesia than lower doses (n = 2) (RR = 1.83; 95% CI: 1.03–3.25; P = 0.038; I² = 0%), with a low level of evidence; benzodiazepines’ amnestic effects were not dose-dependent (n = 3) (RR = 1.54; 95% CI: 0.96–2.49; P = 0.07; I² = 12%) but the evidence was low. A qualitative analysis showed that retrograde amnesia did not occur in 8 out of 10 studies.

Conclusions

In children, moderate evidence support that benzodiazepines induce anterograde amnesia, whereas the evidence for other sedatives is weak and based on isolated and small studies. Further clinical trials focused on the amnesia associated with non-benzodiazepine sedatives are therefore needed.

Trial registration

PROSPERO CRD42015017559.

Memory effects of sedative drugs in children and adolescents--protocol for a systematic review

BACKGROUND

Some sedatives used in children and adolescents can affect memory function. Memory impairment of traumatic experience can minimize the chance of future psychological trauma. Knowledge about the potential of different sedatives to produce amnesia can help in the decision-making process of choosing a sedative regimen. The aim of this systematic review is to evaluate the effect of different sedatives on memory of perioperative events in children and adolescents.

METHODS/DESIGN

Electronic databases and other sources, such as trial registers, gray literature, and conference abstracts will be searched. Randomized controlled trials will be included that assess memory of perioperative events in children and adolescents 2-19 years old receiving sedative drugs as premedication or as agents for procedural sedation in a medical or dental settings. The outcomes will be loss of memory after and before sedative administration (anterograde and retrograde amnesia). Two independent reviewers will perform screening, study selection, and data extraction. Disagreement at all levels will be resolved by consensus or by involving a third reviewer. Assessment of the risk of bias of included studies will be performed according to "Cochrane Collaboration's Tool for Assessing Risk of Bias in Randomized Trials." Clinical and methodological heterogeneity across studies will be evaluated to determine if it is possible to combine or not combine study results in a meta-analysis.

DISCUSSION

To the best of our knowledge, there is no systematic review that specifically addresses this question. Findings from the review will be useful in the decision-making process about the best sedative for minimizing recall of the medical/dental event and possible psychological trauma.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015017559.

Children's play after anaesthesia and surgery: background factors and associations to behaviour during anaesthetic induction

Children can experience anaesthetic induction as fearful and frightening and this can lead to postoperative behaviour changes and symptoms of high anxiety. A fearful experience can also lead to avoidant reactions due to raised negative emotions in situations similar to that, which evoked the fear. To analyse children's reactions after anaesthesia to anaesthetic play equipment, 49 children (three-six years old) were video-filmed during play with anaesthetic equipment 14 days after anaesthesia and surgery. The risk that the child avoided playing with anaesthetic equipment was increased if the child took the premedication unwillingly and if the child was younger. The risk for not telling about the experience was increased if the child took the premedication unwillingly and if the child showed signs of shyness. The risk for telling mostly unspecific memories increased if the child was younger and if the child showed signs of shyness. Avoidant reactions could bee seen in 50 percent of the children. It is important to be aware of the characteristics of a vulnerable child (age, shyness) and to meet the child without raising negative emotions in any part of the anaesthetic process, in order to avoid negative reactions in future encounters.

Children with learning disabilities

Children with learning disabilities can present numerous challenges in the acute hospital setting. This review article examines the causes and presentations of learning disability, and considers some of the management strategies employed when these children present for surgery.

Effects of midazolam on explicit vs implicit memory in a pediatric surgery setting

RATIONALE

Placebo-controlled studies show that midazolam impairs explicit memory in children undergoing surgery (Buffett-Jerrott et al., Psychopharmacology 168:377-386, 2003; Kain et al., Anesthesiology 93:676-684, 2000). A recent within-subjects study showed that midazolam impaired explicit memory while leaving implicit memory intact in a sample of older children undergoing painful medical procedures (Pringle et al., Health Psychol 22:263-269, 2003).

OBJECTIVES

We attempted to replicate and extend these findings in a randomized, placebo-controlled design with younger children undergoing surgery.

MATERIALS AND METHODS

Children aged 3-6 years who were undergoing ear tube (myringotomy) surgery were randomly assigned to receive midazolam (n = 12) or placebo (n = 11). After surgery, they were tested on explicit (recognition) and implicit (priming) memory for pictures encoded before surgery.

RESULTS

Relative to placebo, the midazolam-treated children showed poorer recognition memory on the explicit task but equivalent priming on the implicit task.

CONCLUSIONS

Overall, it appears that midazolam induces a dissociation between explicit and implicit memory in young children in the pediatric surgery setting. Theoretical and clinical implications of the findings are discussed along with directions for future research.

Clonidine: an alternative to benzodiazepines for premedication in children

PURPOSE OF REVIEW

The aim of this review is to summarize the use of clonidine for paediatric premedication and to make a comparison with benzodiazepines. A routine clonidine premedication protocol is also presented.

RECENT FINDINGS

In the US 50% of young children undergoing surgery receive premedication and midazolam is the most frequently used drug. The number of trials that compare midazolam with active controls are few and this premedicant is not adequately validated. Clonidine is still used as premedication in a small number of centres but the literature on paediatric use of clonidine is steadily growing. A recent review article has concluded that the use of clonidine does enhance the quality of perioperative management in infants and children and more recent publications support the use of clonidine for premedication. Its effect on the circulation is mild but routine atropine administration is recommended. Contraindications to the use of clonidine are few. Apart from a general overview on the effects of clonidine this article will also summarise the published trials that have compared clonidine with benzodiazepines for premedication in children.

SUMMARY

Midazolam the most commonly used drug for paediatric premedication worldwide. Despite having a number of beneficial effects it is far from an ideal premedicant, especially concerning its effect on cognition/amnesia, confusion and long-term behavioural disturbances. Clonidine lacks the majority of the negative effects associated with midazolam and is associated with a number of beneficial perioperative effects. Our clinical experience of replacing midazolam with clonidine as premedicant in children, including also outpatients, has been favourable.

Clonidine in paediatric anaesthesia: review of the literature and comparison with benzodiazepines for premedication

BACKGROUND

Children undergoing anaesthesia and surgery can experience significant anxiety and distress during the peri-operative period, but whether routine premedication is necessary is currently debated. Benzodiazepines are the most frequently used drugs as premedication in paediatric anaesthesia. In the US, 50% of young children undergoing surgery receive premedication and midazolam is the most frequently used drug in this context (1). Nishina and coworkers (2) concluded in a review article in 1999 that clonidine, administered via an oral, rectal, or caudal route, is a promising adjunct to anaesthetics and analgesics to enhance quality of peri-operative management in infants and children. Later publications also support the use of clonidine for premedication (3-6). The aim of this communication is to review the use of clonidine in paediatric anaesthesia and to propose clonidine as a promising alternative to midazolam. Clonidine is associated with a number of beneficial effects in the context ofanaesthesia both in adults and children. Why clonidine is not routinely use in clinical practice despite the massive publication list is to a large extent due to the lack of marketing efforts from the pharmaceutical industry since multiplegeneric preparations are now readily available on most markets. Midazolam is also associated with a number of beneficial effects, but is far from an ideal premedicant in children, especially with regards to the amnesia, confusion and long term behavioural disturbances. Clonidine has contrary to midazolam no effect on respiration. We believe that clonidine is a good alternative to midazolam as premedication in infants and children.

Children's memory for pain: overview and implications for practice

Children's memories of painful experiences can have long-term consequences for their reaction to later painful events and their acceptance of later health care interventions. This review surveys research on children's memory for pain, emphasizing implications for clinical practice. Topics reviewed include consequences of children's memories of pain; the development of memory; differences between explicit (declarative, verbal, autobiographic) memory and implicit (nondeclarative, nonverbal) memory; and individual differences, situational, and methodologic factors affecting memories of pain. Methods to prevent the adverse consequences of remembered pain are addressed with reference to current research on editing or reframing memories.

PERSPECTIVE

This review covers topics of value to clinicians providing care to children undergoing painful procedures. Specific recommendations are offered regarding the importance of acknowledging and assessing children's previous memories of painful experiences, the type of information that benefits children before and after procedures, and the most appropriate questioning strategies. It might be possible to prevent or reduce the adverse effects of memories of pain.