Which is good for pre-operative anxiety? Midazolam, video games or teaching with cartoons: A randomised trial : European Journal of Anaesthesiology | EJA

Secondary Logo

Journal Logo

Anaesthesia

Which is good for pre-operative anxiety? Midazolam, video games or teaching with cartoons

A randomised trial

Sakızcı Uyar, Bahar; Polat, Reyhan; Bolat, Merve; Donmez, Aslı

Author Information
European Journal of Anaesthesiology 38(7):p 744-750, July 2021. | DOI: 10.1097/EJA.0000000000001384
  • Free

Abstract

Introduction

High pre-operative anxiety levels may lead to difficulty in anaesthesia induction, increased need for intra-operative and postoperative analgesia, emergence delirium and postoperative behavioural changes.1–4 The frequency of pre-operative anxiety in children has been estimated to be as high as 50%.5

Many pharmacological and nonpharmacological interventions have been investigated to reduce the incidence, severity and effects of pre-operative anxiety in children.6 The most commonly used drug for premedication in children is midazolam and it is associated with a reduced incidence of pre-operative anxiety and postoperative behavioural changes. However, patient acceptance of midazolam is reduced because of its bitter taste, and it may increase the risk of sevoflurane-associated postoperative delirium.7

Age-appropriate audiovisual interventions such as cartoons and interactive games are effective in reducing pre-operative anxiety in children.8 Audiovisual interventions may be designed to inform patients about the procedure as well as serving as distraction methods.9 However, selection of audiovisual interventions according to the age of the child is crucial.8

To our knowledge, no study has compared premedication with midazolam, audiovisual teaching interventions and audiovisual active distraction techniques for alleviation of pre-operative anxiety in children. We investigated the effects on pre-operative anxiety of premedication with midazolam, active distraction by playing video games on a tablet until loss of consciousness and watching the informative cartoon, ‘Şüko’, about anaesthesia in the pre-operative holding area. The primary endpoints were the change in children's anxiety levels between the baseline and 20 min after the interventions in the pre-operative holding area, while entering the operating room and during anaesthesia induction. The secondary endpoint was induction compliance. As children more than 4 years of age are more susceptible to behavioural interventions and the chosen video games are suitable for children more than 4 years old, we included 5 to 8-year-old children in our study.10

Materials and methods

After approval by the Ethical Committee of Dışkapı Yıldırım Beyazıt Education and Research Hospital, Ankara, Turkey, on 06 November 2017 (42/05) and registration with ClinicalTrials.gov (NCT03530670), this prospective randomised study was performed between August 2018 and June 2019 at Dışkapı Yıldırım Beyazıt Education and Research Hospital. We included 138 consecutive children aged 5 to 8 years, with the American Society of Anesthesiologists physical status I-II, and who were scheduled for elective ambulatory adenoidectomy, adenotonsillectomy and/or myringotomy. The exclusion criteria were the following: chronic diseases, developmental delay, prematurity, neurological diseases, hearing/visual impairment, psychoactive medication use, history of previous surgery and refusal to participate in the study.

Written informed consent from the parents or guardians and verbal permission from the children were obtained. The children were taken to the pre-operative holding area with one of their family members. Baseline anxiety levels (T0) were measured using the modified Yale Pre-operative Anxiety Scale11 (mYPAS). Then, the children were allocated to one of the three groups using a sealed envelope technique: Group M (midazolam), Group S (Şüko) and Group T (tablet). Midazolam (Midolam; Pharmada, İstanbul, Turkey) 0.5 mg kg−1 was administrated orally to the children in Group M. Children in Group S watched the cartoon ‘Şüko Is Being Operated’ on the television in the pre-operative holding area. ‘Şüko Is Being Operated’ (Şüko Ameliyat Oluyor) is a Turkish cartoon about a girl named Şüko who underwent surgery/anaesthesia, and is accessible from https://www.youtube.com/watch?v=FUo0j_Jb-XA. A tablet with age-appropriate videogame applications was given to the children in Group T. The chosen applications were Angry Birds ( Rovio Entertainment Corporation), Subway Surfers ( Kiloo & Sybo 2012 to 2019) and Snail Bob ( Andrei Kovalishin). Children chose or changed the games as they wanted. Children stayed with one of their family members in the pre-operative holding area. After 20 min of the intervention (T1), children's anxiety levels were measured using mYPAS and they were transported to the operation room unaccompanied, as per the policy of our hospital. mYPAS was assessed again while entering the operating room (T2).

In the operating room, standard noninvasive monitoring was applied to all children. After explaining the inhalation induction procedure to children, mYPAS was assessed during mask induction (T3) of general anaesthesia with 50% nitrous oxide in oxygen and 8% sevoflurane. Compliance at induction of anaesthesia was evaluated with the mask acceptance scale.12 Children in Group T were allowed to play the game until they became unconscious. An intravenous cannula was inserted and endotracheal intubation was performed. After the end of surgery, patients were awakened and transferred to the postanaesthesia care unit (PACU). One of the family members was allowed with the child in the PACU.

mYPAS is a 1-min observational checklist that can be used in both the pre-operative holding area and during anaesthesia induction for children more than 2 years old. The Turkish version of the mYPAS was not validated when we were conducting this study and we used the original scale validated by Kain et al.,11 similar to the previous studies conducted in our country.13,14 The validity and reliability of the Turkish version of the mYPAS was published after our study was completed and the sensitivity and specificity of the Turkish version was found to be high, and the predictive value was 92.86%.15 We calculated mYPAS as Kain et al.11 proposed: the total score can range from 23.3 to 100, and any score more than 30 is classified as anxiety, with higher scores indicating higher anxiety levels. mYPAS scores were evaluated by the same observer, trained as suggested by Sadhasivam et al.,16 and the observer was not responsible for the anaesthesia management of patients. Sadhasivam et al.16 suggest that the videotapes of children at induction of anesthesia be reviewed until 80% agreement is obtained with the scores given by a psychologist.

Compliance with anaesthesia induction was evaluated with the mask acceptance scale. We have been using this scale extensively in our institution and our colleagues are familiar with it. The anaesthetist who performed anaesthesia induction rated mask acceptance as follows: excellent = not scared and accepts mask easily, good = slightly scared of mask but could be calmed down easily, moderate = scared of mask and could not be calmed down easily, poor = crying and struggling.12

Statistical analysis

To calculate the sample size, the data from a previous study were used.17 The minimum sample size was estimated as 43 patients for each group with an effect size of 0.71, a power of 90%, and a type I error of 0.05 (R 3.6.1. Open source program, https://cran.r-project.org/bin/windows/base/old/3.6.1/).

Statistical analysis was performed using IBM SPSS Statistics for Windows, version 20.0 (IBM Corp., Armonk, N.Y., USA). Descriptive statistics were presented as numbers (percentage) for categorical variables and as mean ± SD (or 95% confidence interval, CI) for numerical variables. The assumption of normal distribution was examined using the Kolmogorov–Smirnov and Shapiro–Wilk tests for numerical data. If data were not normally distributed, then it was expressed as median [IQR] and analysed with the Kruskal–Wallis test. If a significant intergroup difference was found, a post hoc Mann–Whitney U test with Bonferroni correction was performed. Categorical variables were analysed using the Chi-square test or Fisher's exact test, as appropriate. P value less than 0.05 was considered as statistically significant.

Results

A total of 138 patients, 46 per group, were enrolled in the study to allow for the possibility of dropouts (Fig. 1). The operation of one patient in Group S and one in Group T was postponed. One child in Group T refused to play with the tablet. Another child in Group T was too anxious in the operating room and was sent back to the pre-operative holding area and given midazolam. Therefore, the study was completed with 134 patients. No intergroup differences were observed in terms of demographic data and surgical characteristics (Table 1).

F1
Fig. 1:
Flow diagram of participants
Table 1 - Demographic data and surgical characteristics
Group M (n = 46) Group S (n = 45) Group T (n = 43) P
Age (years) 6.5 ± 1.1 6.6 ± 1.0 6.7 ± 1.0 0.684
Sex 0.130
 Female 30 (65.2)% 26 (57.8)% 19 (44.2)%
 Male 16 (34.8)% 19 (42.2)% 24 (55.8)%
ASA (I/II) 38/8 36/9 40/3 0.195
Type of surgery, n (%) 0.061
 Adenoidectomy 10 (21.7)% 14 (31.1)% 13 (30.2)%
 Adenoidectomy+ myringotomy 7 (15.2)% 12 (26.7)% 10 (23.3)%
 Adenotonsillectomy 29 (63.1)% 15 (33.3)% 19 (44.2)%
 Adenotonsillectomy+ myringotomy 0 (0)% 4 (8.9)% 1 (2.3)%
Duration of Surgery (min) 33.7 ± 11.3 33.5 ± 15.5 34.6 ± 13.9 0.783
Duration of Anesthesia (min) 41.3 ± 12.2 39.6 ± 16.3 41.5 ± 14.3 0.570
Values are mean ± SD and number (%).ASA, American Society of Anesthesiologist; M, midazolam; S, Suko; T, tablet.

There was no difference in the baseline (T0) mYPAS scores among the groups (P = 0.606). The mean mYPAS scores were significantly different among the groups at T1 and T2 (P < 0.001 and P = 0.035, respectively). Specifically, the mean mYPAS score was significantly lower in Group T than in Group S at both T1 and T2 (P < 0.001, P = 0.010, respectively). No intergroup difference was noted in mYPAS value at T3 (P = 0.244) (Table 2).

Table 2 - Modified Yale pre-operative anxiety scale and mask acceptance scores
Group M (n = 46) Group S (n = 45) Group T (n = 43) P
T0 mYPAS 40.7 42.6 40.7 0.606a
1.51 (-0.94 to 2.86, M-S) 1.83 (0.19 to 4.05, S-T) 0.74 (-1.09 to 1.19, T-M)
T1 mYPAS 32.6 34.7c 26.8 <0.001a
1.86 (-0.89 to 3.25, M-S) 7.57 (1.11 to 16.90, S-T) 5.94 (2.00 to 13.65, T-M)
10.86 (8.06 to 17.67, T0-T1) 7.89 (1.49–17.28, T0-T1) 13.86 (2.41 to 30.13, T0-T1)
T2 mYPAS 38.6 42.7d 35.0 0.035a
3.74 (-0.90 to 7.27, M-S) 7.69 (0.87 to 16.21, S-T) 3.03 (1.77 to 8.94, T-M)
2.11 (-0.13–4.09, T0-T2) 0.08 (-0.01 to 0.32, T0-T2) 5.67 (0.51 to 11.84, T0-T2)
T3 mYPAS 38.3 43.7 39.5 0.244a
5.04 (0.29–11.03, M-S) 4.52 (-0.1 to 8.26, S-T) 1.77 (0.39 to 2.77, T-M)
2.34 (0.11–4.79, T0-T3) 2.13 (1.12 to 3.38, T0-T3) 1.12 (-1.41 to 1.43, T0-T3)
Mask Acceptance n (%) excellent/good/moderate/poor 31 (67.4)/12 (26.1)/1 (2.2)/2 (4.3) 28 (62.2)/12 (26.7)/ 3 (6.7)/ 2 (4.4) 27 (62.8)/10 (23.3)/4 (9.3)/ 2 (4.6) 0.912b
Values are mean, mean difference (95% CI), and number of patients (%).M, midazolam; mYPAS, modified Yale pre-operative anxiety scale; S, Suko; T, tablet.T0, baseline; T1, after 20 min of intervention; T2, entering the operating room; T3, mask induction
aKruskal--Wallis test.
bChi-squared test.
cGroup S versus group T, P < 0.001 after Mann--Whitney U test adjusted by the Bonferroni correction.
dGroup S versus group T, P = 0.010 after Mann--Whitney U test adjusted by the Bonferroni correction.

When we classified the mYPAS score more than 30 as anxiety, the prevalence of anxiety did not differ among the groups at T0, T2 and T3 (Chi-squared, P = 0.064, P = 0.095 and P = 0.241, respectively); however, it was lower in Group T (25.6%) than in Group S (66.7%) at T1 (P < 0.001; Fig. 2).

F2
Fig. 2:
Prevalence of anxiety at time points in the groups

Figure 3 illustrates the changes in mYPAS scores over time for each group. There was a significant difference in the mYPAS scores at T1 compared with T0 (P = 0.002). Post-hoc Mann--Whitney U tests showed that there was a significant decrease in the mYPAS scores and this was greater in Group T than in the other two groups (P = 0.002). Compared with the baseline scores, there was a trend for mYPAS scores in the operating room (T2) to be lower in Groups M and T and higher in Group S. There was a significant difference between the groups in mYPAS scores over time from T0 to T2 (P = 0.04). A post-hoc Mann--Whitney U test identified a sigificant difference between groups T and S (P = 0.009). During mask induction, there was a trend for patients in Groups T and M to be less anxious than at baseline, while the ones in Group S exhibited increased anxiety level, but there was no statistically significant difference over time from T0 to T3 (P = 0.492).

F3
Fig. 3:
Change in mYPAS score over time for each group

No intergroup differences were noted in the mask acceptance scores (P = 0.912) (Table 2).

Discussion

In the present study, we compared the effect of passive teaching (group S), active distraction (group T) and midazolam on pre-operative anxiety and found that playing video games is a more effective intervention to reduce anxiety in the pre-operative holding area than taking midazolam or watching the cartoon ‘Şüko Is Being Operated’. Both midazolam and playing video games reduced anxiety while entering the operating room compared with baseline. However, watching the informative cartoon did not reduce anxiety in children at this stage.

Reducing pre-operative anxiety in children should be a part of paediatric anaesthesia management7 and is most commonly achieved using premedication with midazolam.18 However, midazolam has too many disadvantages to be considered the gold standard7; hence, many nonpharmacological interventions, such as parental presence, music therapy, clowns/clown doctors, behavioural programmes and video games, have been studied.19 A systematic review8 of 18 studies concluded that active or passive audiovisual interventions are effective in reducing pre-operative anxiety in children. The review emphasised that peer-modelling pre-operative preparation videos teaching the procedure may be more effective in reducing pre-operative anxiety.8

In studies investigating pre-operative anxiety in children, anxiety evaluations were made at different time points of the pre-operative period. To our knowledge, none of the studies comparing midazolam with distraction techniques have compared baseline anxiety levels and anxiety levels after interventions in the pre-operative holding area. We found that the most effective intervention to reduce anxiety in the pre-operative holding area was playing video games. Patients who played games on a tablet had the lowest anxiety levels and exhibited the highest decrease in anxiety levels compared with baseline. When children play games or watch movies on smartphones or tablets, they continue to focus on it and become unaware of their environment and tend to disregard verbal and tactile stimuli.20,21 In our study, anxiety levels of Group S children were higher than those of Group T children, likely because the Group S children watched the cartoon on a television screen in a large premedication room and could not focus on it sufficiently.

Several studies have investigated anxiety levels while entering the operating room, reaching different conclusions. According to the policy of our hospital, paediatric patients were transported to the operation room unaccompanied. Therefore, we could not investigate the effect of parental presence. Kim et al.17 compared video distraction and parental presence and found that the anxiety levels were lowest in the video distraction group while entering the operating room, and only patients playing video games showed a reduction in anxiety levels from baseline. In studies comparing midazolam and video games, Sola et al.22 did not find any difference in anxiety levels between the groups, but Seiden et al.23 reported that children playing video games had less anxiety than children given midazolam. Cumino et al.24 found that children playing games on a smartphone exhibited no increase in anxiety levels while entering the operating room. In our study, we found that although children playing video games showed similar anxiety levels to children given midazolam, they showed lower anxiety levels than children watching the cartoon ‘Şüko Is Being Operated’ while entering the operating room. Furthermore, the anxiety levels increased only in children watching ‘Şüko Is Being Operated’ compared with baseline. This may be because Group S children were moved away from the television, whereas Group T children were still playing video games while being taken to the operating room. Being taken away from watching television may have refocussed their attention on their situation, raising their environmental awareness, thereby increasing their anxiety.

Previous studies have shown that the most traumatic procedure during the peri-operative period is inhalation induction by mask.25,26 Kim et al.17 found that patients playing video games had lower anxiety levels during mask induction. Patel et al.25 found that anxiety levels increased in patients who were premedicated with midazolam, but decreased in patients playing video games during mask induction. In our study, unlike Patel et al.,25 we demonstrated that anxiety levels during mask induction were lower in children given midazolam and in those playing videogames compared with baseline, and only children watching ‘Şüko Is Being Operated’ exhibited increased anxiety levels.

In a series of 93 patients watching animation films on a smartphone, inhalation induction was achieved successfully in all but one patient.20 Kim et al.17 used the induction compliance checklist to assess cooperation during mask induction and found that patients playing video games were more confident during mask induction. We preferred to use the mask acceptance scale because the scale is routinely used in our hospital and all staff are familiar with it. Unlike Kim et al.,17 we did not find any difference in mask acceptance scores between the groups. Only one child in the Group T had extreme anxiety, and she was sent back to the pre-operative holding area and given midazolam. The communication skills of the anesthesiologist may have been effective in achieving these results because we explained the induction procedure very well to the children and a friendly anesthesiologist who is experienced in paediatric patients performed the induction procedure. This could explain our high rate of mask acceptance and the similarity between the groups. It is also possible that all three interventions have a similar effect on the induction compliance. In our study, the sample size was not calculated to evaluate the induction compliance, and this could be a type II statistical error.

Chow et al. developed an interactive tablet-based application to prepare children for the peri-operative period and wanted them to use this application from 7 to 14 days before and up to the day of surgery. They emphasised that age-appropriate peer-modelling audiovisual interventions may be the best solution for reducing pre-operative anxiety. However, in our study, watching ‘Şüko Is Being Operated’ was not as effective as playing the videogames. We think that this is because the patients watched ‘Şüko Is Being Operated’ for the first time in the pre-operative holding area when their anxiety levels were already high, and thus, they could not concentrate sufficiently on it. If they had watched it in their homes with their families, as in the study by Chow et al.,6 they may have been better able to understand it and prepare themselves for the procedure.

The main limitation of the present study is that the researchers could not be blind to Groups T and S in the pre-operative holding area, and to Group T in the operating room. Another possible drawback was that different anaesthetist administered the anaesthetic and saw the children pre-operatively to explain the procedure. Furthermore, we did not include a control group without any intervention for reducing pre-operative anxiety because we believe that pre-operative anxiety should be prevented in children and every child has the right to enter surgery calmly.

State-Trait Anxiety Inventory for Children (STAIC) can be used to measure anxiety in children.9 Although it is thought to be the gold standard to assess baseline state and trait anxiety in children aged at least 5 years, it was not designed to be used at induction.11 As we aimed to compare the initial anxiety levels and the anxiety levels during induction, we preferred to use the mYPAS, which can also be used during induction. Furthermore, mYPAS was considered as the gold standard to measure child's level of anxiety in the pre-operative setting in a recent review.9

It has been shown that different cultures and social education levels affect pre-operative anxiety in children.27 This could also explain the different results in studies on pre-operative anxiety reduction methods from different countries. Cross-cultural studies should be conducted to investigate the effectiveness of passive teaching and active distraction techniques in greater detail.

To our knowledge, ours is the first study comparing active distraction, passive teaching, and oral midazolam premedication in children. Our results indicate that a passive teaching technique may not be as effective as an active distraction technique. However, we think that future studies in which patients watch the cartoon ‘Şüko Is Being Operated’ at home before coming to the hospital are required. In conclusion, distraction with video games is an effective method that can be used instead of midazolam to reduce pre-operative anxiety, especially in busy clinics, and it has no side effects.

Acknowledgements relating to this article

Assistance with the study: none.

Financial support and sponsorship: none.

Conflicts of interest: none.

Presentation: this study was presented as oral presentation at 53rd National Congress of Turkish Anesthesiology and Reanimation Society, 7 to 10 November 2019, Antalya, Turkey.

References

1. Fortier MA, Del Rosario AM, Martin SR, Kain ZN. Perioperative anxiety in children. Paediatr Anaesth 2010; 20:318–322.
2. Kain ZN, Wang SM, Mayes LC, et al. Distress during the induction of anesthesia and postoperative behavioral outcomes. Anesth Analg 1999; 88:1042–1047.
3. Kain ZN, Mayes LC, Caldwell-Andrews AA, et al. Preoperative anxiety, postoperative pain, and behavioral recovery in young children undergoing surgery. Pediatrics 2006; 118:651–658.
4. Maranets I, Kain ZN. Preoperative anxiety and intraoperative anesthetic requirements. Anesth Analg 1999; 89:1346–1351.
5. Davidson AJ, Shrivastava PP, Jamsen K, et al. Risk factors for anxiety at induction of anesthesia in children: a prospective cohort study. Paediatr Anaesth 2006; 16:919–927.
6. Chow CHT, Van Lieshout RJ, Schmidt LA, Buckley N. Tablet-based intervention for reducing children's preoperative anxiety: a pilot study. J Dev Behav Pediatr 2017; 38:409–416.
7. Rosenbaum A, Kain ZN, Larsson P, et al. The place of premedication in pediatric practice. Paediatr Anaesth 2009; 19:817–828.
8. Chow CH, Van Lieshout RJ, Schmidt LA, et al. Systematic review: audiovisual interventions for reducing preoperative anxiety in children undergoing elective surgery. J Pediatr Psychol 2016; 41:182–203.
9. Kim J, Chiesa N, Raazi M, Wright KD. A systematic review of technology-based preoperative preparation interventions for child and parent anxiety. Can J Anaesth 2019; 66:966–986.
10. Varughese AM, Nick TG, Gunter J, et al. Factors predictive of poor behavioral compliance during inhaled induction in children. Anesth Analg 2008; 107:413–421.
11. Kain ZN, Mayes LC, Cicchetti DV, et al. The Yale Preoperative Anxiety Scale: how does it compare with a ‘gold standard’? Anesth Analg 1997; 85:783–788.
12. Sekerci C, Dönmez A, Ateş Y, Okten F. Oral ketamine premedication in children (placebo controlled double-blind study). Eur J Anaesthesiol 1996; 13:606–611.
13. Hatipoglu Z, Gulec E, Lafli D, Ozcengiz D. Effects of auditory and audiovisual presentations on anxiety and behavioral changes in children undergoing elective surgery. Niger J Clin Pract 2018; 21:788–794.
14. Batuman A, Gulec E, Turktan M, et al. Preoperative informational video reduces preoperative anxiety and postoperative negative behavioral changes in children. Minerva Anestesiol 2016; 82:534–542.
15. Hatipoglu Z, Kırdok O, Ozcengiz D. Validity and reliability of the Turkish version of the modified Yale Preoperative Anxiety Scale. Turk J Med Sci 2019; 49:730–737.
16. Sadhasivam S, Cohen LL, Hosu L, et al. Real-time assessment of perioperative behaviors in children and parents: development and validation of the perioperative adult child behavioral interaction scale. Anesth Analg 2010; 110:1109–1115.
17. Kim H, Jung SM, Yu H, Park SJ. Video distraction and parental presence for the management of preoperative anxiety and postoperative behavioral disturbance in children: a randomized controlled trial. Anesth Analg 2015; 121:778–784.
18. Kain ZN, Hofstadter MB, Mayes LC, et al. Midazolam: effects on amnesia and anxiety in children. Anesthesiology 2000; 93:676–684.
19. Manyande A, Cyna AM, Yip P, et al. Nonpharmacological interventions for assisting the induction of anaesthesia in children. Cochrane Database Syst Rev 2015; CD006447.
20. Low DK, Pittaway AP. The ’iPhone’ induction: a novel use for the Apple iPhone. Paediatr Anaesth 2008; 18:573–574.
21. Radesky JS, Schumacher J, Zuckerman B. Mobile and interactive media use by young children: the good, the bad, and the unknown. Pediatrics 2015; 135:1–3.
22. Sola C, Lefauconnier A, Bringuier S, et al. Childhood preoperative anxiolysis: is sedation and distraction better than either alone? A prospective randomized study. Paediatr Anaesth 2017; 27:827–834.
23. Seiden SC, McMullan S, Sequera-Ramos L, et al. Tablet-based Interactive Distraction (TBID) vs oral midazolam to minimize perioperative anxiety in pediatric patients: a noninferiority randomized trial. Paediatr Anaesth 2014; 24:1217–1223.
24. Cumino DO, Vieira JE, Lima LC, et al. Smartphone-based behavioural intervention alleviates children's anxiety during anaesthesia induction: a randomised controlled trial. Eur J Anaesthesiol 2017; 34:169–175.
25. Patel A, Schieble T, Davidson M, et al. Distraction with a hand-held video game reduces pediatric preoperative anxiety. Paediatr Anaesth 2006; 16:1019–1027.
26. Kain ZN, Caldwell-Andrews AA, Krivutza DM, et al. Inter-active music therapy as a treatment for preoperative anxiety in children: a randomized controlled trial. Anesth Analg 2004; 98:1260–1266.
27. Mamtora PH, Kain ZN, Stevenson RS, et al. An evaluation of preoperative anxiety in Spanish-speaking and Latino children in the United States. Paediatr Anaesth 2018; 28:719–725.
Copyright © 2020 European Society of Anaesthesiology and Intensive Care. Unauthorized reproduction of this article is prohibited.