Article, Pediatrics

The association of preprocedural anxiety and the success of procedural sedation in children

Original Contribution

The association of preprocedural anxiety and the success of procedural sedation in childrenB,BB

Kevin M. Schreiber MD, Sandra J. Cunningham MD*, Sergey Kunkov MD, MS, Ellen F. Crain MD, PhD

Department of Pediatrics (Emergency Medicine), Jacobi Medical Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA

Received 10 June 2005; revised 6 October 2005; accepted 27 October 2005

Abstract

Purpose: To investigate the association between a child’s preprocedural state anxiety and the success of sedation.

Methods: A consecutive sample of children aged 2 through17 years requiring sedation for a procedure was enrolled. Pain, preprocedural anxiety (range, 0-9), and success of sedation (10 = most successful) were measured.

Results: Fifty-nine patients were enrolled. The median age was 7 years. The median Anxiety score was

1.0 (interquartile ratio, 0-3). Pain and anxiety were weakly correlated (r = .21, P N .10). The mean sedation score was 7.8 (F2.2). Preprocedural anxiety and successful sedation were inversely correlated (r = –0.31, P = .002). Sedation was successful in 81% of children with anxiety scores below the median and 52% with anxiety scores above the median ( P = .02). Children with low anxiety were 3.8 times more likely to be successfully sedated (95% confidence interval, 1.19-12.14).

Conclusion: Our data suggest that preprocedural state anxiety is associated with the success of sedation in children.

D 2006

Introduction

Procedural sedation is frequently required for the care of children in the emergency department (ED). The purpose of sedation is to maintain patient comfort while providing optimal compliance to facilitate a procedure. Successful

Presented in part at the Pediatric Academic Societies’ Annual Meeting, San Francisco, Calif, May 2004.

B Reprints not available from the author.

BB No financial support received for this study.

* Corresponding author. Tel.: +1 718 918 5250; fax: +1 718 918 7459.

E-mail address: [email protected] (S.J. Cunningham).

procedural sedation produces a state of calm and stillness with maintenance of cardioRespiratory function, protective reflexes, and airway control [1]. To ensure maintenance of these vital functions during sedation in the ED, the amount and type of medication must be limited [2]; occasionally, sedation is inadequate, and the child remains uncomfortable with excessive movement. Many of these children appear anxious during the procedure.

Previous studies in children have reported that inadequate sedation is associated with the age and weight of the child and the number of medications used [3]. No association has been found between inadequate sedation and sex, time of

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day, or diagnosis [4,5]. The relationship between preproce- dural anxiety and the success of sedation among children, for whom therapeutic and Diagnostic procedures may be especially frightening, has not been studied.

Increased anxiety has been shown to be associated with lower effective levels of c-aminobutyric acid (GABA) in the brain. Both an absolute reduction in GABA levels and decreased receptor affinity for GABA produce a similar effect. Medications used for sedation cause an increase in the efficacy of GABA [6]. Benzodiazepines and narcotics cause an increase in the concentration of GABA, and ketamine has been shown to enhance the affinity of GABA for its receptor, thereby increasing its functional concentration.

The objective of this study was to assess preprocedural anxiety using a newly developed anxiety scale and to investigate the association between preprocedural anxiety and the success of procedural sedation.

Methods

This was a prospective cohort study conducted in a pediatric emergency department in an urban public hospital. Children aged 2 through 17 years, who required sedation for a procedure, were enrolled. Children with moderate to severe developmental delay were excluded.

Scale development

A review of the medical and psychiatric literature revealed no anxiety scales for children younger than 5 years. In addition, most scales developed for older children measure trait rather than state anxiety [7]. The character- istics of certain anxiety conditions in young children, such as separation anxiety, have been well described [8]. Other

authors have described characteristics of anxiety in older children that are remarkably consistent [9,10]. Using this information, we developed a scale to measure state anxiety in children from ages 2 through 17 years. Three domains were identified: (1) motor, (2) verbal, and (3) affect. Behaviors were described in each domain, confirmed by a second set of expert judges, and were assigned a score of zero through 3. The scores in each of these domains were summed to provide a total anxiety score, with a range of zero through 9. The scale will be referred to as the Jacobi Anxiety Scale (Fig. 1). Before initiation of the study, ED nurses were trained in the use of the Jacobi Anxiety Scale to minimize variation in observer technique.

Study protocol

A triage nurse assessed the child’s pain using a standard number scale ranging from zero to 10 for children 9 years or older, or a 10-point Wong-Baker faces pain scale for children younger than 8 years [11]. Using the Jacobi Anxiety Scale (range, 0-9; 9 = most anxious), a nurse measured the child’s level of anxiety before the procedure or any other potentially painful interventions, including intravenous catheter placement or wound cleansing. The measurement was determined while the nurse was speaking with the child and performing nonpainful procedures such as placement of the oximetry probe and electrocardiogram leads. To assess the degree to which the anxiety scale was performed as it was intended, scores on the anxiety scale were compared with the clinical assessment of the child’s anxiety by the pediatric emergency medicine (PEM) physician administering the sedation and the physician performing the procedure. Each physician independently rated the child’s anxiety on a scale from 1 (calm) to 5 (very anxious). Both physicians were blinded to the anxiety score

Fig. 1 Jacobi Anxiety Scale.

recorded by the nursing staff. All children were sedated using standard weight-based protocols with finite medica- tion amounts and limited repeat dosing. The primary outcome measure was the success of sedation. Sedation success was measured immediately after the procedure by the PEM physician administering the sedation and the physician performing the procedure. Each physician independently rated the child’s apparent comfort and degree of movement during the procedure using a measurement scale with continuous numerical values. Comfort was rated on a scale from 1 (miserable) to 5 (very relaxed); movement was rated from 1 (excessive) to 5 (none). The scores were summed to provide a sedation score from 2 to 10, with 10 being the most successful sedation. Demographic information, the type of procedure performed, and drug and dosage administered were recorded. The pain scale, the Jacobi Anxiety Scale, and the sedation scores were independently recorded.

Data analysis

Data were analyzed using SPSS (version 12.0) (SPSS, Chicago, Ill). Means with SDs or medians with interquartile ranges (IQRs) were determined for age, the pain scale, the Jacobi Anxiety Scale score, and the sedation score. The j statistic was used to assess agreement between the ratings of the child’s preprocedural anxiety by the PEM physician sedating the child and the physician performing the procedure, as well as both physicians’ rating of sedation. spearman correlation and the v2 test were used to assess the association between the Jacobi Anxiety Scale score assigned by the nurse and the impressions of the child’s preproce- dural anxiety level, as measured by the 2 physicians, as well as the relationships between pain and anxiety, pain and success of sedation, and anxiety and success of sedation. Ninety-five percent confidence intervals around proportions were calculated.

The Committee on Clinical Investigations of the Albert Einstein College of Medicine and Jacobi Medical Center approved the study protocol and determined that written consent was not required.

Results

Fifty-nine patients were enrolled; no patient refused to participate. The median age was 7 years (IQR, 4-12), and 43 (73%) were boys. All children received parenteral sedation: ketamine (49%), fentanyl and midazolam (32%), morphine and midazolam (11%), and etomidate (6%). Ninety-eight percent of children were sedated for painful procedures, including fracture reduction (53%), laceration repair (24%), abscess drainage (10%), shoulder reduction (5%), para- phimosis reduction (3%), and foreign body removal (3%). The median pain score assessed by the triage nurse was 8 (IQR, 4-10). The distribution of Jacobi Anxiety Scale scores is noted in Fig. 2. The median anxiety score assessed

Fig. 2 Distribution of Jacobi Anxiety Scale scores.

by the staff nurse was 1 (IQR, 0-3). Pain and anxiety were weakly correlated (r = 0.21, P N .10). The mean global ratings of anxiety by the PEM physician sedating the child and the physician performing the procedure were 2.8 (F1.5) and 2.5 (F1.4), respectively. There was excellent agreement between the summary sedation scores calculated from both physicians’ ratings of the patients’ apparent comfort and degree of movement (j = 0.72). The mean sedation scores reported by the PEM physician sedating the patient and the physician performing the procedure were 7.8 (F2.2) and 7.8 (F2.3), respectively. For further analysis, we defined successful sedation as scores above the mean, reflecting a better-than-average score for both comfort and movement. Because both physicians’ ratings of the children’s global anxiety and sedation were essentially the same, we will report the ratings from the PEM physician sedating the child for the remaining comparisons. There was no difference in the success of sedation by age ( P = .16). The physician’s global rating of anxiety correlated moderately well with the Jacobi Anxiety Scale score, as rated by the nursing staff (r = 0.43, P b .001). Pain and the success of sedation were poorly correlated (r = –.07, P = .6). There was a moderate inverse correlation between the Jacobi Anxiety Scale score measured by the nursing staff and the sedation score measured by the physician. Children with lower preproce- dural anxiety had more successful sedation compared with children with greater anxiety (r = –0.31, P = .002). Sedation was successful in 29 (81%) of 36 children with anxiety scores below the median and in 9 (52%) of 23 children with anxiety scores above the mean ( P = .02). Children with low anxiety (score V1) were 3.8 times more likely to be successfully sedated (odds ratio, 3.8; 95% confidence interval, 1.19-12.14).

Discussion

Our study demonstrates that preprocedural state anxiety is associated with the success of procedural sedation. Using sedation protocols with restricted maximum and increment

dosing, children with higher levels of anxiety were more likely to be inadequately sedated, as compared with children with lower levels of preprocedural anxiety. Studies from the adult literature have demonstrated the impact of both trait and state anxiety on successful sedation and anesthesia. Bonta et al [12] demonstrated increased ease in the introduction of an echoendoscopic probe for the perfor- mance of endoscopic ultrasonography in adults who received midazolam, compared with placebo before their procedure. A study by Maranets and Kain [13] found that adults with high preoperative anxiety, assessed by the State- Trait Anxiety Inventory, had increased induction and intra- operative anesthetic requirements. These patients were undergoing general anesthesia in the operating room with cardiopulmonary support. Procedural sedation and anesthe- sia administered outside the operating room has tended to be more limited because patients must independently maintain cardiopulmonary function and protective reflexes. Because of these limitations, inadequate sedation may be an undesirable outcome in some procedures. The lack of movement may be the most important criterion of successful sedation to the physician performing the procedure, but to the parent, it might be comfort or lack of crying. Therefore, we measured success of sedation as a continuous variable based on these 2 factors, rather than as a categorical variable. Sedation scales, such as the Ramsay Scale, the Sedation-Agitation Scale, and the Harris Scale, are often used as an assessment of agitation in critically ill patients and are measured as continuous rather than categorical variables [14]. These scales are subjective measurements of the depth of sedation, whereas our sedation scale assesses the adequacy of sedation, as demonstrated by the child’s apparent Comfort level and degree of movement.

To rate a child’s preprocedural anxiety, we developed an instrument appropriate for use in an acute care setting, which also would address the various developmental stages in our age range of 2 through 17 years. A search of the literature revealed no suitable validated instruments. The anxiety scales previously developed are for use in older children and are very lengthy. One scale, the Revised Children’s Manifest Anxiety Scale [15] is recommended only for children older than 6 years. Moreover, the Revised Children’s Manifest Anxiety Scale is one of the briefest scales yet contains more than 35 items, making it impractical for use in an emergency department setting. In addition, most scales measure trait rather than state anxiety, including the Childhood Anxiety Sensitivity Index [16], the Hamilton Anxiety Rating Scale [17], and others [8].

The Jacobi Anxiety Scale has not been validated in other populations, and there are no validated instruments for comparison. However, we believe our measure has face and sampling validity because it includes constructs from the literature on child anxiety as well as developmentally appropriate behaviors from several domains. We found excellent correlation between the Jacobi Anxiety Scale scores recorded by the nursing staff and the physician’s

global rating of the child’s preprocedural anxiety. The high correlation between the Jacobi Anxiety Scale and the clinicians’ rating of anxiety suggests that both the Jacobi Scale developed for this study, as well as the clinicians, are measuring the same construct. Because older children have a broader behavioral repertoire, it may be difficult for a busy clinician to identify anxiety using simple global assessment. However, we found no association between age and anxiety or the success of sedation.

We did not investigate the association between the types of medication used for sedation and the success of sedation because the type of medication used must be tailored to the clinical circumstances, and there is no one drug that can be used in all situations. Furthermore, we did not report on the absolute dosage of the drug because all the medications we use for procedural sedation are administered using weight-based protocols with strict limitations of maximum dosage.

Because pain and anxiety are interrelated and almost all of our patients were being sedated for painful procedures, it was important to determine the degree to which our anxiety measure was correlated with pain. The weak correlation between pain and anxiety in our study suggests that the target constructs of our anxiety scale were not the same as pain.

Some limitations to our study included the use of the Jacobi Anxiety Scale as the only measure of anxiety. Because the Jacobi Anxiety Scale is not validated in other populations, there is a possibility that it is not measuring the construct it was intended to measure. However, there was high correlation between the scale and physician ratings of the child’s anxiety. We did not relate changes in vital signs to scores on the Jacobi Anxiety Scale because vital sign changes occur with pain as well as anxiety, making them less specific [10,11]. In addition, we did not assess the potential contribution of trait anxiety or familial and Environmental factors to the child’s preprocedural anxiety, and these factors may play an important role. The Jacobi Anxiety Scale was completed when the child was in the treatment room and before any potentially painful interventions, such as intravenous catheter place- ment. However, the child’s response to the placement of monitoring equipment, such as the pulse oximetry probe or electrocardiogram leads, was included in the anxiety scale score. Other elements of the environment were not constant, such as the number of people in the treatment room or the noise level elsewhere in the ED. The Jacobi Anxiety Scale was measured at one point in time and, although we attempted to keep this uniform, there may have been fluctuations in a child’s level of anxiety throughout the preprocedural period.

Another limitation of our study is that physicians administering the medications for procedural sedation were confined by the protocols that are in place in the ED. To insure the safety of patients, our sedation protocols have strict limits concerning the maximum amount of drug that

can be used per dose, as well as the maximum number of allowable incremental doses. Although the weight-based dosing of the medications used follows standard recom- mendations, the limitation of maximum and repeat dosing is self-imposed. While minimizing the rate of complications and adverse events, this may impact the rate of successful sedation. With increasing evidence-based data that certain drugs such a ketamine may be repeated safely to achieve the desired effect, some drug protocols may be liberalized [18]. However, other drugs, such as etomidate, which leads to a decrease in cortisol levels after 1 dose and has the potential for clinically significant Adrenal insufficiency after repeated doses [19], may be a poor choice in the child with high preprocedural anxiety.

Successful sedation is essential to the delivery of quality medical care. Prior studies have hypothesized several factors associated with the adequacy of sedation in children, yet none have investigated the possibility of anxiety as a major contributing factor. Anxiety has been shown to be involved in the same neural pathways as sedative medi- cations; therefore, there is likely a connection between anxiety and sedation.

We found that the level of a child’s preprocedural anxiety and the success of the sedation were strongly correlated. Because drug type and, in some cases, the amount, are limited in the ED setting, nonpharmacologic strategies to lower a child’s anxiety before a procedure may play a vital role in improving the effectiveness of sedation. In addition, assessment of a child’s preprocedural anxiety may aid the physician in determining the best route and type of medication to be used and to anticipate that the anxious child will likely have increased medication requirements.

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