Quality of Trials
Adequate allocation concealment was found in four RCTs (9,12,13,15). Inadequate allocation concealment was found in two RCTs (10,18). There were two double-blinded RCTs (9,15) and four single-blinded RCTs (6,8,14,17).
This outcome was measured in eight RCTs. Although the full-version Spielberger State and Trait Anxiety Inventory was used in four RCTs (11,13–15), before and after state anxiety (transient situation) levels were measured in three RCTs (11,13,15). Combining these 3 trials showed that state anxiety (transient situational) levels before anesthesia were decreased in subjects receiving the video and/or printed information compared with those receiving no intervention (WMD of 3; 95%CI, 1–5) (Fig. 1). When the analysis was limited to trials involving parents of children undergoing surgery (11,15), the reduction in state anxiety levels in the video group was significant compared with the control group (WMD of 2; 95%CI, 0–5).
There was no reduction in state anxiety levels when a pamphlet and video group was compared with a pamphlet-only group (WMD of 1.00; 95%CI, −0.53–2.53) (19). In one trial, when pre- and postintervention trait anxiety (stable, dispositional) levels were measured, there was no change between the groups (13). When an abbreviated version of the Spielberger’s State and Trait Anxiety Inventory was used, there was no significant difference between the video and control group in state and trait anxiety scores after adjusting for baseline measurements (9).
Because there were various methods of measuring anxiety in children, we did not attempt to pool the results. Margolis et al. (8) found no significant difference in children’s anxiety (as measured by Global Mood Score) between the groups in the preoperative holding area, operating room, and during anesthetic induction. Parents of children in the intervention group reported lower anxiety levels (visual analog scale 4.5 ± 3.7) than the control group (visual analog scale 5.8 ± 5.0) but this difference was not significant (8). Similarly, there was no significant difference in children’s anxiety (as measured by an observational visual analog scale and Yale Preoperative Anxiety Scale by a blinded assessor) between control and video groups after the intervention, in the preoperative holding area and during induction (15). In contrast, parents in the video group were significantly less anxious (Amsterdam Preoperative Anxiety Scale) than parents in the control group (P < 0.0001) (11).
Using a visual analog scale, patients in the pamphlet group were less anxious about pain management compared with a control group (P < 0.01) (17).
There was no standard method of measuring the level of patient knowledge. The Standard Anesthesia Learning Test was used in one RCT (11) to assess the factual knowledge of anesthesia procedures and risks. There was a significant increase in knowledge scores in the video group compared with the control group (P = 0.02) (11).
A metaanalysis of 2 RCTs (9,14) showed that patients in the video group were more likely to answer all knowledge questions correctly compared with patients with no intervention (RR of 6.64; 95%CI, 2.05–21.52). The video intervention was most effective in educating patients about risks of anesthesia (RR of 7.12; 95%CI, 3.70–10.07) than the process of anesthesia (RR of 1.27; 95%CI, 1.10–1.34) after adjusting for preintervention state and trait anxiety levels (9). After adjusting for previous anesthesia experience and preoperative state and trait anxiety scores, patients in the video group were more likely to identify misconceptions about anesthesia correctly than patients who did not have the video intervention (RR of 3.15; 95%CI, 1.94–4.29) (9).
The level of knowledge about pain management, as measured by the percentage of correct responses to a knowledge questionnaire, was higher in the video group compared with patients with no intervention (WMD of 17%; 95%CI, 9–25) (12,18). Parents of children who had previously been exposed to pain management had significantly less improvement in knowledge scores after viewing the video than those with no previous exposure (12). In another trial, the mean score for understanding the use of patient-controlled analgesia device and pain management was higher in the pamphlet group than in the control group who had received instructions from a physician (16). For example, control patients were 3 times more likely to believe that they could overdose themselves with patient-controlled analgesia than patients in the video group (RR of 2.80; 95%CI, 1.11–7.09) (16). Klafta and Klock (7) found that more patients in the video group were able to identify neuraxial analgesia as a potential method of postoperative pain relief (P = 0.02).
Courtney (10) found that an anesthetic booklet was valuable because patients had a better understanding of what a premedication would do and how long after an anesthetic to wait before driving. Although more patients in the booklet group knew what procedures to take if they were not feeling well before outpatient surgery than patients in the control group, neither group knew that an anesthesiologist was a specialist doctor or what they did during anesthesia (10). Zvara et al. (6) concluded that the video intervention was not effective, because there were no significant differences in the proportion of correct responses found between groups for questions about the process of anesthesia.
Patient satisfaction with the media was not well defined in any of the RCTs and was not measured using validated questionnaires. More patients in the video group believed that it helped them prepare for surgery than patients in the control group (92% versus 74%, P = 0.01) (20). In another RCT (6), 85% of patients who viewed a video found it to be helpful compared with 42% of control patients who thought it might be helpful (P < 0.01). The results were not pooled because there was statistical heterogeneity (Q statistic of 11.43, P < 0.01), probably because of the style of video presentation [general narration (6) versus personal narration (20)].
When patient satisfaction with media-based intervention was defined as the expected versus actual experience in the operating room, there was no difference between the intervention and nonintervention groups (RR of 1.06; 95%CI, 0.93–1.22) (8,14,20). More parents in the interactive book group than parents in the control group believed that they had received enough information (82% versus 65%, P = 0.05) (8). There was no difference in the proportion of patients who wanted more detailed information than what was given (69% video group versus 84% control group, P = 0.07) (20). Also, there was no difference in the level of patient satisfaction with knowledge of perioperative events or knowledge about anesthetic practice between booklet and control groups (10).
Reducing patient anxiety has been defined as one of the principles of conducting a preanesthetic consultation (1). This systematic review has shown that there was a significant reduction in state anxiety levels attributable to media-based patient education before anesthesia. However, this reduction was small—at most, a change in five points. An important clinical change in state-anxiety levels has been defined as 1 standard deviation (10 points) using the Spielberger’s state anxiety self-administered questionnaire (score 20–80) (21). Therefore, the clinical significance of this finding is debatable. Quantitative and qualitative analysis of pediatric trials suggest that media-based interventions can decrease anxiety for parents but not for the children who are patients.
Only one RCT in this systematic review measured the association between anxiety and recovery (17). Not surprisingly, there was no association because these outcomes are influenced by other factors, such as socioeconomic issues or individual surgical practices (17). The postoperative quality of recovery is probably a more useful outcome to use for assessing the effectiveness of an education intervention (38). In a recent trial, a significant correlation was found between increased anxiety and reduced quality of recovery (39). Patients with preoperative state anxiety are nearly 3 times more likely to have postoperative anxiety (odds ratio = 2.65; 95%CI, 1.70–4.14), which in turn is associated with moderate-to-intense postoperative pain (odd ratio = 2.62; 95%CI, 1.77–3.88) (40).
The optimal duration and timing of media to educate patients about anesthesia are unclear, because there were insufficient trials for a sensitivity analysis to be done. Half of the trials in this systematic review included interventions given on the day before or on the day of surgery. Arellano et al. (41) showed a small reduction in state anxiety scores when patients were seen by an anesthesiologist immediately before surgery compared with those seen at an outpatient clinic one week before surgery or at the time of admission to the hospital. The logistics of providing media-based interventions close to the time of anesthesia should be weighed against giving patients sufficient time to cope with and reflect on the information gained. Patients vary considerably in the amount of information they think appropriate and this varies within individuals over time (21). Providing detailed information about risks of complications of general anesthesia on the night before surgery did not increase patients’ levels of anxiety (22). Miller et al. (23) suggested that parents of pediatric surgery patients experience greater levels of anxiety and need for information than do adults who are undergoing surgery themselves.
The main benefit from video and written information was an increased level of patient knowledge about risks and the process of anesthesia and pain management. The benefits of explaining the risks of anesthesia include satisfying responsibility and understanding in parents of healthy pediatric patients (42). Identification of subgroups of patients who would benefit most from media-based interventions is a challenge. Greenberg et al. (12) found that parents of children with less educational experience and who had not been exposed to pain management gained the most benefit from a video intervention.
Factual knowledge of anesthesia can improve compliance with perioperative instructions and facilitate informed consent (11). None of the trials in this systematic review examined the impact of media-based intervention on patient compliance with perioperative instructions. Despite being given detailed oral and written instructions, patients were noncompliant with fasting instructions (2%), took medications contrary to advice (7%), and intended to drive home after ambulatory surgery (4%) (43). Patient noncompliance may result in cancellation of surgery or unanticipated perioperative complications. Therefore, the use of media, together with reinforcement by an anesthesiologist, may have an important role in increasing patient compliance with perioperative instructions.
Patient satisfaction is a complex psychological phenomenon and should be assessed by multiitem questionnaires that have been shown to be reliable and valid. A limitation in this systematic review was that the included trials relied on single-item rating for patient satisfaction without established validity and reliability properties. We found no significant difference between intervention groups in expected versus actual experience in the operating room. The question of how helpful a video is in preparing patients before anesthesia seems to depend on the style of video presentation (20). A video presentation from a patient’s perspective allows other patients to take a more active role in the perioperative situation because this process of identification induces a higher degree of anticipatory coping (20). Patients want both procedural and sensory information (44) which may partly explain the heterogeneity observed between the two trials assessing the usefulness of a video intervention (6,20).
The applicability of the results of this quantitative systematic review was limited to video and/or printed information interventions and there was no direct comparison between the two methods. Although the World Wide Web is becoming an important source of medical information, preliminary evidence suggests that the quality of information for patients is unreliable and poor (45). Other methods, such as CD-ROM programs, may be more comprehensive in content and satisfy a broader range of educational needs but are probably more expensive to develop than videos and printed information (46). A recent survey showed that patients most preferred to learn about anesthesia by individual instruction by staff, followed by video, written materials, and the Internet (30). However, the most cost-effective and practical method of delivering patient education remains to be addressed.
The quality of trials in this systematic review was fair. Only 4 of 15 trials in this review had adequate allocation concealment. Compared with trials with adequate allocation concealment, trials with unclear allocation concealment have been shown to exaggerate the treatment effect by 30%(25). Therefore, it is possible that the presence of publication bias and the quality of trials included in this review may be overestimating any beneficial effects of media-based interventions. We did not formally assess publication bias using the method of Egger et al. (47) because there were few trials with dichotomous outcomes for metaanalysis.
Effective patient education requires good communication skills, consideration to adult learning and teaching principles, and selecting the media to suit the individual patient’s needs (48). Written information is successful in a proportion of the population because it requires basic literacy skills as well as the motivation to read the material provided (49). In comparison, videos are useful in that patients learn by seeing a demonstration of perioperative processes. Overall, this systematic review supports the use of video and printed information about general process and risks of anesthesia for patient education before surgery. These interventions were associated with increased patient knowledge (an important component of an informed patient consent) and a small reduction in anxiety levels. However, there was no effect on patient satisfaction. Future trials are needed to address which medium is more effective and its impact on patient compliance with perioperative instructions.
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