Prevention and Intervention Strategies to Alleviate Preoperative Anxiety in Children

Preoperative anxiety (anxiety regarding impending surgical experience) in children is a common phenomenon that has been associated with a number of negative behaviors during the surgery experience (e.g., agitation, crying, spontaneous urination, and the need for physical restraint during anesthetic induction). Preoperative anxiety has also been associated with the display of a number of maladaptive behaviors postsurgery, including postoperative pain, sleeping disturbances, parent-child conflict, and separation anxiety. For these reasons, researchers have sought out interventions to treat or prevent childhood preoperative anxiety and possibly decrease the development of negative behaviors postsurgery. Such interventions include sedative premedication, parental presence during anesthetic induction, behavioral preparation programs, music therapy, and acupuncture. The present article reviews the existing research on the various modes of intervention for preoperative anxiety in children. Clinical implications and future directions are discussed.

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.

Effects of benzodiazepines on explicit memory in a paediatric surgery setting

RATIONALE

Many laboratory-based studies indicate that benzodiazepines impair explicit memory performance, increase sedation, and impair attention.

OBJECTIVES

The present study was designed to extend prior lab-based findings to an applied setting in which the amnestic effects of benzodiazepines may be beneficial for users. In addition, the study extended the previous adult-focused research by examining the cognitive effects of benzodiazepines in children.

METHODS

The present study examined the use of a specific benzodiazepine (midazolam) as a premedicant among 40 children aged 4-6 years old having ear tube (myringotomy) surgery, who were randomly assigned to receive midazolam or placebo.

RESULTS

Consistent with previous studies, the results indicated that midazolam causes significant amnesia on a cued recall task. In addition, free recall for post-drug events were also impaired by midazolam relative to placebo, indicating that benzodiazepine-induced amnesia occurs even for highly salient information.

CONCLUSIONS

Overall, it appears that benzodiazepines do impair memory in a pediatric population. This amnesia was not secondary to the inattention and sedation also caused by midazolam administration. The theoretical and clinical implications of these findings are discussed, as are potential future studies.

Cognitive and sedative effects of benzodiazepine use

This paper reviews the effects of benzodiazepines (BZs) on the performance of tasks measuring human cognitive abilities. The paper reviews the most common cognitive side effects of BZs: increased sedation, decreased attention, and anterograde amnesia. In particular, this paper focuses on recent findings regarding time course-related effects on BZ-induced deficits in explicit and implicit human memory performance. Specifically, we reviewed recent research indicating that both explicit memory and priming are impaired by BZs if the encoding task takes place near the time of the theoretical peak plasma concentrations of the drug. Although BZs also appear to increase objective and subjective sedation, as well as to impair attentional processing, these other cognitive impairments do not appear to fully account for the widespread memory deficits caused by BZ administration. The theoretical and clinical implications of benzodiazepine-induced memory impairments are discussed.

Heartbeat awareness and heart rate reactivity in anxiety sensitivity: a further investigation

We examined the effects of anxiety sensitivity (AS) and arousal induction on heartbeat awareness and heart rate reactivity in a nonclinical undergraduate sample. Students were randomly selected from a larger screening sample to fill two groups (high and low AS; n = 15 per group) based on Anxiety Sensitivity Index (ASI) [Peterson, R. A., & Reiss, S. (1992). Anxiety Sensitivity Index manual (2nd ed. revised). Worthington, OH: International Diagnostic Systems] scores. Participants completed a mental arithmetic/spelling task to induce arousal. At two phases (i.e., baseline vs. stress), participants estimated their heart rates during specified intervals using a mental tracking paradigm. Actual heart rates were simultaneously measured. Although heart rate did increase significantly from baseline to stress phases, high and low AS groups did not differ in terms of heart rate reactivity to the stressor. As hypothesized, high AS individuals were more accurate in estimating their actual heart rate as compared to low AS individuals. Contrary to hypothesis, the AS group differences in accuracy of heartbeat estimations did not vary across baseline vs. stress phases. Interestingly, only low AS individuals provided heart rate estimates which were significantly lower than their actual heart rate readings. Although high and low AS individuals did not differ in actual heart rate, high AS individuals provided significantly higher heart rate estimates than low AS individuals. These results are consistent with the interoceptive sensitivity hypothesis. Implications of the greater heartbeat awareness of high AS individuals are discussed.

An examination of differences in the time course of oxazepam's effects on implicit vs explicit memory

The present study was designed to examine the effects of oxazepam on implicit vs explicit memory processes, as a function of this drug's time course. The effects of oxazepam (30 mg) or placebo on directly comparable tests of implicit memory (word stem completion) and explicit memory (cued recall) were examined at three time points: 100 min post-drug administration (prior to the theoretical peak plasma concentration of oxazepam; i.e.'pre-peak' condition), 170 min post-drug (close to theoretical peak; i.e. 'peak' condition) or 240 min post-drug (following theoretical peak: i.e. 'post-peak' condition). Sixty healthy volunteers were randomly assigned to either the drug condition or the placebo condition in a double-blind design and were tested on both memory tests at one of the three time points. In the 'pre-peak' condition, oxazepam impaired cued recall performance relative to placebo but did not impair priming. In the 'peak' condition, oxazepam impaired performance on both memory tasks. In the 'post-peak' condition, cued recall performance in the oxazepam group remained significantly impaired relative to placebo. However, oxazepam-induced impairments in priming were only marginal, suggesting that oxazepam-induced impairments in implicit memory processes begin to wane following theoretical peak drug concentrations. The fact that oxazepam-induced priming impairments were significant only when the word stem completion task was administered close to peak plasma concentrations, supports the hypothesis that benzodiazepines exert time-dependent effects on implicit memory processes. The results also support the theoretical distinction between implicit and explicit memory processes, since the directly comparable implicit and explicit tasks showed different impairment curves over time.

A further examination of the time-dependent effects of oxazepam and lorazepam on implicit and explicit memory

Until recently, research indicated that all benzodiazepines impair explicit memory, while only lorazepam impairs priming. Stewart and associates provided preliminary data which indicated that both oxazepam and lorazepam may impair implicit memory, but in a time-dependent fashion. The present study was designed to replicate Stewart et al.'s findings after overcoming several limitations of the original study. Thirty subjects were administered an acute dose of lorazepam (2 mg), oxazepam (30 mg) or a placebo and were tested with an implicit (word-stem completion) test and an explicit (cued recall) test. However, subjects were only tested at 170 min post-drug (close to oxazepam's theoretical peak concentration) to rule out the possible "explicit memory contamination" explanation of the Stewart et al. implicit memory findings. Consistent with previous research, both drugs impaired explicit memory relative to placebo. Also, both lorazepam and oxazepam impaired priming performance, supporting the "time-dependence" interpretation of the Stewart et al. findings. The results also indicate that episodic memory is impaired by both benzodiazepines in a time-dependent fashion even when the research methodology used involves everyday memory demands.