Surgical patients often experience preoperative anxiety associated with fears related to anaesthesia and its implications. In surgical patients, anxiety can worsen perceptions of pain, delay recovery and decrease overall satisfaction with perioperative care.1,2 Anaesthetic information and preoperative educational interventions can decrease patient anxiety. Specifically, preoperative anaesthetic information videos have proven effective in the reduction of preoperative anxiety.3,4
The three dimensions of preoperative anxiety are fear of the unknown, fear of feeling ill and fear of death.5 Despite growing evidence that viewing preoperative anaesthetic information videos can reduce perioperative anxiety, previous studies have exhibited serious shortcomings.3,5 Firstly, few have used longitudinal data with more than two time points and few have examined predictors of perioperative anxiety such as age, sex, previous anaesthesia and psychological distress, over different time periods. Secondly, most studies have analysed populations in the United States or in other countries in the Organisation for Economic Cooperation and Development (OECD), which differ from those in geographical areas with relatively lower incomes or with different cultural backgrounds. Thirdly, when analysing longitudinal data, such studies rarely apply the appropriate statistical methodology to control for censoring and intercorrelations arising from repeated measures obtained from the same patient pool.
Therefore, the present study had two objectives. The first was to evaluate the effect of viewing an anaesthetic patient information video on anxiety levels in patients scheduled to undergo surgery. The second objective was to identify patient factors that were associated with a high risk for the development of preoperative anxiety.
Materials and methods
This study was approved by the Institutional Research Ethics Committee of Pingtung Christian Hospital, Taiwan on 11 January 2011 (document number PTCH-235A). Written informed consent was obtained from all patients who participated in the study. The individuals were invited to participate in the study on the day of their hospital visit for preoperative assessment and surgery. For this randomised controlled trial, trained research assistants in the preoperative clinic used random number tables to assign individuals to experimental and control groups and then collected baseline data. Inclusion criteria were age at least 18 years and the ability to read and understand Chinese. The only exclusion criterion was the postponement of the scheduled surgery.
The same three trained research assistants performed all data collection procedures in each group. The anaesthesiologists performed preoperative assessments, provided information about the risks and benefits of the required anaesthetic procedures and potential alternatives and answered questions from the patients. Before this preoperative assessment (ie T1), each individual completed a questionnaire regarding demographic characteristics (age, marital status and weight), previous surgical procedures (type of surgical procedure and type of anaesthesia) and the use of sleeping pills. The Chinese version of the Spielberger State Trait Anxiety Inventory (STAI), a self-reported psychological instrument used as the primary outcome measure in this study, was then given to the patients.6 This 40-item inventory has two parts: a state scale (STAI-S) and a trait scale (STAI-T). The Cronbach-α (estimated reliability) values are 0.89 for the STAI-S and 0.85 for the STAI-T. The responses to the 20 statements on the STAI-S form are used to determine the current anxiety level of the patient. The STAI-T form contains 20 statements related to the general disposition of the respondent to anxiety. The STAI-S and STAI-T forms require respondents to rate their agreement with each statement using a scale from 1 to 4 representing not at all, somewhat, moderately and very much, respectively. The STAI-T and STAI-S were completed by the patients at the preoperative clinic (T1). The STAI-S was repeated at the preoperative holding area before surgery (T2) and on the third day after surgery (T3). The total score on each scale ranges from 20 to 80 points wherein higher scores reflect higher anxiety. During their visit to the preoperative clinic and after the anaesthetic pre-assessment, the experimental group watched an 8 minute educational video, whereas the control group received an 8-min verbal briefing on anaesthesia. This verbal briefing is standard procedure at this institution. The standard anaesthetic verbal briefing included a description of the procedures for administering sedation, general or spinal anaesthesia in addition to information on fasting protocols. The purpose of the verbal briefing was to explain the anaesthetic process and related safety procedures. The 8-min educational anaesthetic video developed for this study included the following five topics: assessment at the preoperative clinic and preoperative care, including confirmation of patient identity and surgical site by staff; conduct of general anaesthesia; conduct of spinal anaesthesia; administration of sedation; and postoperative care, including the management of pain and postoperative nausea and vomiting (PONV). After either the verbal briefing or the video patients could ask further questions. Experts evaluated and approved of the content of the video before use in this study. The video used in this study was filmed and produced by the Anesthesiology Department at Pingtung Christian Hospital.
The type of surgery was categorised as upper abdominal surgery (including laparoscopic cholecystectomy and choledocholithotomy), lower abdominal surgery (including herniorrhaphy of inguinal, umbilical and ventral hernia) or other (including thyroidectomy, mastectomy and lower limb surgery). Data collection for each patient also included the duration of surgery, episodes of PONV and postoperative opioid use during hospital stay in either the postanaesthetic care unit or ward. Each patient with PONV was counted only once regardless of the frequency of emetic symptoms within the 24 h following surgery.
The patient satisfaction questionnaire was completed on the third day after surgery. This single-item self-reported inventory measured the overall satisfaction of the patients with their medical care. Total scale scores ranged from 20 to 100, with higher scores indicating higher satisfaction with the medical services received. The questionnaire had a Cronbach-α (estimated reliability) of 0.94.
Demographic and clinical characteristics were analysed by descriptive statistics. For continuous variables, the mean [standard deviations (SD)] was calculated. For categorical variables, the number and percentage distribution was calculated for each category. Two-sample t-tests and one-way analysis of variance were used to compare continuous measures in groups of two and in groups of three or more, respectively. Uncorrected Chi-square analyses were used to compare categorical measures between the groups. The distribution of the STAI-S scores at each time point was analysed in terms of median, range and interquartile range (IQR). To compare two time intervals, effect size was used to standardise the extent of change measured by the STAI-S. The effect size is the difference between the mean scores for two time intervals divided by the SD in the previous (or formal) time interval score. An effect size of 1.0 is equivalent to a change of 1 SD in the sample. Effect sizes of 0.2, 0.5 and 0.8 are generally interpreted as small, medium and large changes, respectively.7 Normality of distribution of the repeated measures was tested by Shapiro–Wilk Test. Nonnormal distributions and high within-individual correlations indicated that longitudinal relationships could not be analysed by ordinary regression methods, which assume independent observations. The generalised estimating equations approach was developed to correct for repeated outcomes within the same individual.8 To determine average score improvements, multiple time points of follow-up examinations were included in the generalised estimating equations model with the STAI-S score as the outcome variable. Univariate models were then used to assess effective predictors of change in the STAI-S scores at different time points when using the baseline STAI-S measures.
Five points on the STAI-S score may or may not be relevant or important. As STAI scores are subject to bias resulting from differences in medical procedures, bias is likely in studies that compare patients who undergo different procedures. The sample size in this study was sufficient to detect a five-point difference in all STAI-S scores over time, assuming α of 0.05, power of 80% and an intertemporal, between-score correlation of 0.6. In addition, on the basis of the literature, 40 patients per group were expected to provide sufficient power to demonstrate an effect size of 0.5 at the 5% significance level, which corresponded to a moderate but clinically significant change in anxiety status.9 SPSS 18.0 software for Windows and Stata Statistical Package (Stata Corp., College Station, Texas, USA) was used for all statistical analyses and a P value less than 0.05 was considered statistically significant.
Of the 105 eligible individuals who gave written consent to participate and who were enrolled in the study at baseline, five were excluded due to postponement of their surgery. Fifty patients were randomly assigned to the experimental group and 50 were assigned to the control group. All patients completed the questionnaires. Table 1 summarises the demographic data for the two groups. Other than baseline STAI-T scores, which were higher in the experimental group, the two groups were well matched in terms of baseline patient characteristics. The STAI-T scores also revealed no significant difference in patient anxiety between the two groups in the generalised estimating equations model.
CONSORT flow diagram (Fig. 1).
At T1, the two groups did not significantly differ in STAI-S scores. According to baseline STAI-S scores, more than 45 patients in each group were classified as having high anxiety (Fig. 2). Notably, at T2, the STAI-S scores revealed significantly lower anxiety in the experimental than in the control group (P < 0.001). The standard verbal briefing, however, had not significantly decreased anxiety in the control group. The experimental group revealed significantly lower STAI-S scores after surgery (T3) than at either T1 or T2. From T2 until after surgery, state anxiety scores were higher in the control group than in the experimental group (Table 3). Figure 2 shows box plots illustrating the similar STAI-S score distributions in the experimental and control groups at different time points.
The effect size refers to the method used to standardise the size of the change in STAI-S between different time points when comparing the experimental and control group (Table 2). A notable finding was that after the patients had viewed the anaesthesia video, STAI-S scores revealed a significant decrease in the intensity of anxiety (P < 0.001). The experimental group had a large effect size (ES) change at T2 and a medium ES change at T3 (−0.65 and −0.36, respectively).
Comparisons of postoperative recovery revealed that the use of opioid analgesics did not differ significantly between the experimental group and control group in either the postanaesthetic care unit (14 vs. 18%, respectively) or in the general ward (40 vs. 46%, respectively). Comparison of the incidence of PONV also revealed no significant difference between the experimental group (8%) and the control group (10%). The overall mean (SD) patient satisfaction score was significantly higher in the experimental than in the control group [90.2 (12.3) vs. 84.0 (17.4) respectively; P = 0.043]. Table 3 summarises the results of univariate models used to analyse demographic characteristics and postoperative recovery in terms of associations with STAI-S scores. The following patient characteristics and postoperative outcomes showed significant (P < 0.05) associations with STAI-S scores: age; previous anaesthesia; baseline STAI-S; and overall patient satisfaction.
This prospective study demonstrated that the patients who viewed an educational video on anaesthesia during their preoperative visit had lower anxiety levels and higher overall satisfaction with their medical care than controls who received a standard verbal anaesthetic briefing. Unlike the control group, the experimental group showed a large and medium effect size in anxiety reduction in the preoperative holding area and the third day after surgery, respectively. Previous studies have confirmed the effectiveness of patient education interventions in reducing preoperative anxiety.3,10 In addition, in terms of STAI-S scores in the preoperative holding area, similar methods of reducing patient anxiety reported in earlier studies did not achieve comparable efficacy. The reduction in anxiety can be attributable to the audiovisual presentation indicating that it might be easier to understand a video presentation than a purely verbal briefing. Hence, a preoperative video seems to be more effective at familiarising patients with anaesthetic procedures and postoperative care.
Many patients experience substantial anxiety prior to surgery. Studies in this area indicate that patient anxiety may result from lack of information in the preoperative period.11 The ‘fear of feeling ill’ component of anxiety was assessed by measurements of PONV and postoperative pain. The preoperative video addressed these two dimensions and described the experience that patients should expect during the perioperative period. Previous studies of surgical patients indicate that preoperative anxiety is reduced by having had positive experiences in previous surgery, feeling a sense of security and caring, being well informed and having positive expectations.12
Use of the STAI to quantify the effects of preoperative assessment by an anaesthesiologist has shown that such assessments reduce patient anxiety.13,14 The combination of an anaesthetic pre-assessment and the preoperative anaesthetic video effectively reduced anxiety in the experimental group by providing positive expectations and emotional support. Unlike other studies, however, the control group in this study had high anxiety levels in the postoperative period. Two earlier studies of postoperative patients showed that intense anxiety can result from insufficient information, negative preoperative mood symptoms and diminished self-respect, quality of life and social function.15,16 In patients with a high number of negative mood symptoms before surgery, the number of symptoms tends to remain high after surgery. One interesting issue that merits further study is cultural differences in the need for supportive care. For example, a Hong Kong study concluded that the main concern of Hong Kong Chinese women is receiving adequate information about their disease and treatment, whereas the main concern of German white women is receiving adequate physical and psychological support.15
The experimental group had significantly higher overall satisfaction scores than the control group. The results correlated with the STAI-S scores of the experimental group at T2 and T3.
The second objective of the study was to identify patients at high risk of preoperative anxiety. The STAI-S scores at follow-up were negatively associated with age and positively associated with previous experience of anaesthesia. Domar et al.17 concluded that anxiety in surgery patients did not correlate with age or with previous surgery or anaesthesia. However, other studies have reported that preoperative anxiety tends to be increased in young patients and is associated with previous negative experiences while undergoing anaesthesia.5,18 Younger patients apparently had a strong interest in information about surgery and anaesthesia in the preoperative period. In younger patients, anxiety may result from inadequate information. In addition, patients who had previous negative experiences, such as PONV, shivering and postanaesthetic pain, did not have higher than average preoperative anxiety or more positive expectations about anaesthesia. Therefore, patient education about the practice of anaesthesia and the roles of anaesthesiologists must be improved to overcome this lack of understanding. Baseline STAI-S scores were positively associated with changes in STAI-S scores at follow-up. Patients with high baseline anxiety tended to have high perioperative anxiety at follow-up.
Satisfaction ratings are intended to be subjective; their purpose is to capture personal evaluations of care that cannot be determined by direct observation of patients. In agreement with previous studies, high preoperative anxiety negatively affected patient satisfaction with general outcomes.19
The following limitations of this study are acknowledged. First, baseline STAI-T scores and categories of surgery were controlled by the generalised estimating equations model. Patient anxiety did not significantly differ by baseline STAI-T score or by surgery type; however, as the study was designed to detect this difference, this negative finding is likely to have resulted from the small sizes of these subgroups. Therefore, further studies in a larger population are needed. Second, although the preoperative video reduced patient anxiety in the experimental group, this study did not measure the potentially important effects of knowledge retention in terms of anxiety reduction. Third, this study did not explore other potential predictors of patient anxiety, such as income level, cultural structure, surgical techniques, disease stage, self-respect or quality of life.
In conclusion, in a geographically homogenous population, preoperative anxiety was lower and perioperative satisfaction higher in patients who watched an educational video on anaesthesia than in patients who received standard anaesthetic information delivered verbally.
Acknowledgements relating to this article
Assistance with the study: none.
Financial support and sponsorship: none.
Conflicts of interest: none.
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