Extended preoperative patient education using a multimedia DVD—impact on patients receiving a laparoscopic cholecystectomy: a randomised controlled trial

  • D. Wilhelm
  • S. Gillen
  • H. Wirnhier
  • M. Kranzfelder
  • A. Schneider
  • A. Schmidt
  • H. Friess
  • H. Feussner
Controlled Prospective Clinical Trials

Abstract

Purpose

The informed consent is a legal requirement prior to surgery and should be based on an extensive preoperative interview. Multimedia productions can therefore be utilised as supporting tool. In a prospective randomised trial, we evaluated the impact of an extended education on patients undergoing cholecystectomy.

Materials and methods

For extended patient information, a professionally built DVD was used. After randomisation to either the DVD or the control group, patients were informed with or without additional presentation of the DVD. The quality of education was evaluated using a purpose-built questionnaire.

Results

One hundred fourteen patients were included in the DVD and 98 in the control group. Patient characteristics did not differ significantly despite a higher educational level in the DVD group. The score of correctly answered questions was higher in the DVD group (19.88 vs. 17.58 points, p < 0.001). As subgroup analysis revealed, particular patient characteristics additionally impacted on results.

Conclusion

Patients should be informed the most extensively prior to any surgical procedure. Multimedia productions therefore offer a suitable instrument. In the presented study, we could prove the positive impact of an information DVD on patients knowledge. Nevertheless, multimedia tools cannot replace personal interaction and should only be used to support daily work.

Keywords

Informed consent Surgery Multimedia DVD Education 

Introduction

The informed consent of patients undergoing surgery is a legal requirement prior to any surgical intervention. It requires the patients’ free decision whether an intervention can be done or not. As the patient normally possesses only lay knowledge concerning specific procedures and does not have the ability to capture all potential consequences of a surgical procedure, the education dialogue is an essential issue and has to communicate all relevant information [1]. The extent of communicated information is still in discussion and depends on the type of surgery to be performed (elective plastic surgery vs. acute intervention for traumatic injury).

The missing informed consent or its inadequate form and extent are one of the main points of criticism in case of medico-legal affairs and comprehends about one third of all lawsuits against doctors in Germany [2] and most likely also in other countries.

Many factors seem to effect on the quality of the informed consent, such as the use of oral or written information or the implementation of illustrations [3, 4, 5]. Additionally, patient characteristics, such as age or intelligence quotient, impact on understanding medical educations [6, 7], but have to be taken as given and not influenceable.

Consequently, to raise the quality of the informed consent, one has to improve the way in which information is presented. A step-by-step education is seen to be superior and does impact significantly on the patients knowledge, but is demanding to be realised in daily practice [2, 8]. Accordingly, supporting methods for patient education, to be used as a supplement to conventional dialogue, are of highest interest.

As described elsewhere, the use of visual information brought by video and computer animations probably can correspond to these needs [9, 10, 11]. Several studies tried to evaluate its impact on patients knowledge but with inconsistent results [8, 12, 13, 14, 15]. Some of the studies investigated only small collectives, which might be a reason for unclear benefit of the extended education, but also quality and extend of the presented media might have had contributed on the results. Fortunately, computer science has made relevant steps ahead over the past years, allowing now realistic multimedia productions with high interactivity.

The goal of this study was to construct a digital versatile disc (DVD) at a highest pedagogical level using all recently available technologies and to evaluate its impact on the quality of the informed consent in a large group of patients. The evaluation was realised as a prospective randomised trial.

Materials and methods

Interactive DVD—cholecystectomy

The DVD was designed by the Institute of Media Informatics of the University of Munich and in close cooperation with the Department of Surgery of the Technische Universität of Munich as an educational tool to inform about laparoscopic surgery for cholecystolithiasis. As laparoscopic cholecystectomy is increasingly performed in short-stay surgery with tight time schedules, the potential benefit of an educational tool should become even more evident; furthermore, this disease affects all age groups and genders, allowing investigations on a large collective.

The DVD content is mainly based upon literature studies, clinical information leaflets and on direct discussions with surgeons. The DVD is sectioned into five chapters containing basic information about cholecystolithiasis and its pathophysiology (02:58 min), the potential course of the disease without treatment (complications due to cholecystolithiasis; 03:13 min), therapeutic principles, with focus on surgical treatment (laparoscopic or conventional cholecystectomy; 08:30 min), possible complications following surgery (07:45 min) and at the end, interviews with patients prior and after surgery (03:10 min).

The DVD is realised in standardised PAL format (720 × 576, 25 frames/s, true colour, country code 2) with a total length of 26 min. The DVD includes written text and pictured information, complex three-dimensional computer animations and video sequences. Construction of the content was realised by Macromedia Flash Pro® (Adobe Systems, USA), 3dsMax® (discreet, Autodesk, USA) and the Adobe video package (Adobe Photoshop®, Premiere Pro®, Encore®, Adobe Systems, USA). The DVD includes an audio commentary spoken by a professional commentator.

The central topic of the disc is an education dialogue between a surgeon and a pretended patient personated by a professional actor. The dialogue is supported by explaining computer animations and text fields giving additional information to the user.

It was emphasised to construct a medium which conforms to highest pedagogical principles by utilising all currently available technologies. The quality of the DVD and the correctness of the presented information were assessed by experienced computer scientists and media developers as well as by experienced surgeons.

Evaluation of the DVD

Evaluation of the DVD on patient education was based upon a multiple choice questionnaire consisting of 25 questions, which was handed out during postoperative consultation in our outpatient department 1 week after discharge from hospital.

Each patient undergoing laparoscopic cholecystectomy was informed about the upcoming surgery 1 week prior to admission to hospital. In the DVD group, patient education was realised by direct conversation with the surgeon and additional presentation of the education DVD “Interactive DVD Cholecystectomy”.

The control group was educated traditionally by sole conversation with the surgeon, without seeing the disc.

All patients were assigned randomly to either the DVD or the control group using a specifically built randomisation list and after having given informed consent concerning participating the study.

The questionnaire was mainly composed of 21 specific questions concerning the underlying disease, the operation performed and potential complications (the specific knowledge which should be gained during patient education dialogue before surgery). Four additional general questions were asked to evaluate the quality of the presented disc and to estimate patients’ satisfaction for extended education (additional use of a DVD compared to sole conversation).

The questionnaire was designed and developed by a team of surgeons unaware of the content of the DVD and unaware of presented information.

For further evaluation, demographic parameters (gender, age, etc.) of all patients were included in the database as well as the level of education (elementary vs. high school degree) and the command of language. Additionally, parameters concerning the performed operation and the educational process are recorded.

The point-score resulting from correctly answered questions was calculated for both groups. As some questions allowed for more than only one correct answer, the maximum score achievable was 30 for the specific part of the questionnaire (21 questions). Four supplementary questions were interpreted separately.

SPPS for Microsoft Windows, version 11.0 was used for statistical analysis using the Mann–Whitney test to test for significant differences between two or more groups and the linear regression model for multivariate analysis; a test value below 0.05 was regarded as significant. Data schedules were drawn with the help of Microsoft Excel, version 2007.

Results

Two hundred fifty-nine patients who underwent laparoscopic cholecystectomy between May 2005 and May 2007 were included in the study, wherefrom 212 (81.8%) patients did fill in and return the questionnaire in time. The number of patients in the DVD group (patient who had seen the DVD) was slightly higher compared to the control the group, with 114 persons in the DVD and 98 persons in the control group. Patient characteristics of both groups did not differ in regard to age, gender and nationality, but showed a significant difference concerning the educational level (Table 1). Duration of the information process was 25:26 min longer in the DVD group, as additional time was required for presentation of the DVD. However, during this, period no medical assistant was required.
Table 1

Demographic data of the collective

 

DVD group

Control group

Total

Test value

Total number of patients

  

259

 

Number of patients included

114

98

212

n.s.

Mean age

52,8

53,7

53,2

n.s.

Gender (m/f)

33/81

31/67

64/148

n.s.

Nationalitya (g/e)

89/25

80/18

169/43

n.s.

Educationb (+/−)

53/61

32/66

85/127

p = 0.046

ag native-born German or patients living in Germany for over 20 years, e foreign patients

b+ high school degree, − elementary school degree

Evaluation of the questionnaire showed the following results:

Supplementary questions

Only 84% (178/212) of all patients remembered the doctors’ name having informed about potentially complications of the intervention. Interestingly, most of those patients who did not remember the surgeons’ name marked the name of the leading surgeon of the ward, who did not take part in the education. Moreover, another 15 patients (7.1%) of the complete collective was unaware of having signed the informed consent. As shown in Table 2, both questions did not reveal a significant difference between both groups.
Table 2

Results for supplementary questions

 

DVD group

Control group

Total

Test value (p)

Remember educationing doc’

94/114

84/98

178/212

0.415

Remember having signed

107/114

90/98

197/212

0.328

Comprehensibility

4.58

4.49

4.54

0.951

Information content

4.64

4.6

4.62

0.834

Ninety-six per cent of all patients in the DVD group judged the quality of the information process easy to be understood, whereas 4% of patients could not understand the bigger part of provided information. In this context, the control group showed similar results without a statistical difference. In a value ranking from 0 to 5, with 5 being the highest value demonstrating high comprehensibility, mean value was 4.58 for the DVD and 4.49 for the control group (p = 0.951).

Concerning the quantity of information provided by both methods of patient information, the majority of subjects was generally satisfied (DVD and control group). The mean score (ranking 0 to 5 as highest value) was 4.64 in the DVD and 4.60 in the control group. Again, there was no statistical difference between both groups (p = 0.834). The entire evaluation of supplementary questions is displayed in Table 2.

As already mentioned, the main part of the questionnaire focused on specific aspects of the past information process and tried to figure out which patient characteristics might have influenced the results.

As shown in Fig. 1, a significant difference in the mean score can be demonstrated for the DVD group, reaching 19.88 points after completing the extended education including the DVD. For the control group, mean score was 17.58 points, thus significantly lower (p = 0,001).
Fig. 1

Mean score values differed for both groups (1 DVD group, 2 control group), with the DVD group scoring significantly higher (p = 0.001)

In a subgroup analysis, the impact of different characteristics on the mean score, initially irrespective of the fact having received an extended education or not, was evaluated.

Displayed in Figs. 2, 3 and 4, a relevant influence on the mean score was observed concerning the age of patients, the aspect of using the native or a foreign language and the educational level. All differences reached a significant level.
Fig. 2

Influence of different age groups on the mean score for specific questions; the test value was calculated at p < 0.001, thus significant

Fig. 3

Different scores for well-educated patients and patients without higher education. The analysis reveals a positive influence of education, respectively, intelligence on understanding information. p < 0.001

Fig. 4

Influence of the lingual background (native born Germans and patients living in Germany for more than 20 years vs. foreign patients); understanding of German impacts relevantly on the outcome. p < 0.001

If particular questions were analysed in comparison of the two groups, one could identify identical results for basic textual questions (e.g. which organ was removed?) and for more complex questions (e.g. why a conversion to open surgery might become necessary?), but significantly better results in case of figurative questions concerning anatomical structures which had to be identified in a non-labelled illustration. In this context, the DVD group showed a better overall outcome (p < 0,001).

For further subgroup analysis and measurement of the influence of extended education, a significantly higher score was identified for young subjects in the DVD group (23.74 points highest score), whereas middle-aged and older patients did not reflect a positive effect of an extended information process (Fig. 5). Comparable results were recognised concerning the lingual background of the collective and its educational level, again in comparison between the both groups. Highest scores were achieved by well-educated patients having received an extended education and native-born patients of the same group.
Fig. 5

Influence of the patients age on both groups. The highest score resulted for young patients receiving an extended education, whereas middle-aged and older patients did not have a relevant benefit from watching the multimedia DVD

In multivariate analysis using the linear regression model, the mode of education, the command of language, the patients age group as well as the educational level proved to have a significant impact on the point score. All results were summarised in Tables 3 and 4.
Table 3

Influence of patients’ characteristics on mean scores for specific questions

 

DVD group

Control group

Test value (p)

Influence of age

<40 years

23.7

18.7

0.001

41–60 years

20.4

18.5

0.090

>60 years

16.2

15.9

0.566

Influence of nationality

Native speaker

21.8

18.4

<0.001

Foreign speaker

12.6

14.1

0.587

Influence of education

High school degree

22.8

21

0.003

Elementary school degree

17

16.1

0.165

Table 4

Predicting factors for effectiveness of preoperative patient education

Parameter

t valuea

p value

Group (DVD or test group)

0

0.028

Educational level

−3.2

0.001

Age group

−4.3

<0.001

Command of language

−5.9

<0.001

at values below −2 or above +2 indicate relevance of the parameter

Discussion

The education dialogue to obtain the informed consent prior to surgery is a vital point in the relationship between patient and surgeon. It is the basic prerequisite for the patients’ confidence in medical care and therefore has to be as empathetic and careful as even possible. On the other hand, the informed consent is absolutely essential as a legal requirement for all surgical procedures. To rule out most of postoperative legal disputes because of failures in treatment, the surgeon has to inform the patient of potential complications resulting from his medical action.

To accommodate this importance, the informed consent was the object of investigation of numerous studies, which attempted to improve its quality to a higher level. Referring to these studies, the information process and the resulting level of education of a patient is supposed to have a major impact on postoperative anxiety and pain [9, 12, 15, 16, 17, 18, 19, 20]. Beyond this Yeh et al.[13] identified an impact on patients’ autonomy and recovery after total hip replacement before and after discharge from hospital. Patients receiving additional information brought by a multimedia CD-Rom even could be discharged significantly earlier from the hospital than those in the control group. Identical findings with earlier discharge from hospital were also reported by Kulik and Mahler [21].

It could furthermore be demonstrated that the preoperative information dialogue is influenced by patients’ personal characteristics such as patients’ age, the intelligence quotient and the emotional status at time of the dialogue [6, 5, 2].

Regarding these studies, the improvement of the informed consent and the understanding concerning planned interventions should be an endeavour to each doctor.

As even the traditional education dialogue is rather time-consuming, tools assisting the doctor during this procedure would be of great value. The highest impact on the quality of informed consent actually is given by a step-by-step information with repetitive dialogues between doctor and patient [2, 5]. Unfortunately, this proceeding is even more time-consuming than traditional ways of patient education; thus, the practical relevancy of this recommendation is low. Also, the use of additional written information is regarded to have a positive effect in the informed consent [22]; however, Luck et al. [9] reported that it positively impacts only on a small proportion of the population, as it requires at least basic education and enough motivation to study the provided material.

Alternatively, the supportive use of multimedia tools offers an attractive and much more convenient way to improve the patient knowledge prior to surgery.

Most studies concerning multimedia information transfer were carried out in the field of anaesthesia [11, 12, 23], but also for surgery, the impact of an extended patient education using audiovisual assistance was realised [22, 23, 24]. Exemplarily, Stergipoulou [16, 17] compared patients’ knowledge and postoperative outcome concerning the effect of a preoperative informative session using a Multimedia Health Educational program. He could demonstrate the profit of patients receiving additional information prior to laparoscopic cholecystectomy, although the collective evaluated comprehended only 15 patients. Therefore, the evidence of this study is considerably limited.

Fortunately, interactive computer programs are highly accepted by the majority of patients [14, 8]. The use of animations and video sequences allows illustrating even abstract information. Furthermore, the percentage of information kept in mind is much higher if the information is mediated in a synchronous audiovisual manner, as compared to simple oral information [24].

Evidently, the exclusive use of oral or written information for patient education is certainly not recommendable and not corresponding to the technical facilities available.

However, the benefit of multimedia tools for patient education prior to surgery has not been proven in a representative collective until now. In addition, the quality of multimedia productions continuously increases; hence, already published studies were based on recently antiquated technologies and subsequent studies are potentially of importance.

For these reasons, we evaluated the impact of an up-to-date interactive DVD, which was developed with professional didactic knowledge. To obtain high evidence, the study was performed on a large patient collective as a prospective, randomised controlled trial.

For various reasons and as observed elsewhere [16], we focused on patients undergoing laparoscopic cholecystectomy. For this collective, it could be demonstrated that the informed consent is improved by the additional presentation of an elaborated multimedia DVD, which provides all information necessary for preoperative patient education. The impact reached statistical significance. Though all patients, irrespectively if they received the traditional or the alternative extended education, judged the information dialogue as very informative and comprehensive, the score of information recall at 1 week after surgery was markedly higher if the DVD was included. This somehow reflects a gap between the patients need for information and the objective level of knowledge. The results are only limited by the fact that the percentage of patients with high school degree was significantly higher in the DVD group; therefore, the better outcome in the DVD group could potentially be caused by the higher educational level and not by the additional DVD information process. But as detailed analysis revealed, scores were always higher if the DVD was used, the same for collective with high school degree as for the collective without. The same could be demonstrated by multivariate analysis showing that the additional use of the DVD is an independent predictive factor. Therefore, we believe the extended education to impact relevantly on the informed consent and the patient knowledge. Young and well-educated patients overall did show the highest scores in the questionnaire, but the maximum score could even be improved by additional DVD presentation. Similar results were basically identified by comparing native-born patients to foreign patients, with worse results for the latter. Foreign patients being informed by additional DVD presentation had even lower scores, which might result from informational overload, which might confuse a specific subgroup of patients; on the other hand, multimedia tools do not provide the ability to extensively address on persons with a need for adaptive education, such as foreigners or especially as older patients.

The passive remembrance of information gained by the education dialogue was 66% for patients having seen the DVD and 59% for those who did not. Therewith, the percentage of information recall is relevantly higher as described in older studies [2, 6]. Two possible explanations are conceivable: The quality of the basic education dialogue inherently is superior compared to those of the quoted publications, or the basic knowledge of included patients concerning the performed intervention was already higher before entering the hospital, as in other studies. As one of the quoted studies [2] was partly performed by our institution but the collective was completely different (traumatic surgery in an acute setting), we suggest that an increased knowledge provided by health educational programs and by public media might be a reason for this better outcome.

Two results of our investigation are remarkable. Only 84% of all patients remembered the informing doctors’ name and as much as 7% of all patients did not even remember having signed the informed consent leaflet. This demonstrates a separate group of patients, hard to be informed on a high level because of personal characteristics, but maybe the reluctance of receiving detailed information concerning the surgical therapy. Interestingly, this group showed a significantly lower degree of satisfaction concerning the amount of mediated information (3.7 vs. 4.8, with 5 as the maximum score showing high satisfaction) and the comprehensibility of the educational dialogue (3.3 vs. 4.8, maximum score 5).

Extended education using additional tools like the mentioned multimedia DVD has a significant impact on postoperative patient knowledge and improves the quality of the informed consent. This prospective, randomised controlled trial could prove this fact on a large collective. Though we did not investigate on patient outcome concerning anxiety and pain, a positive impact on these parameters can also be expected according to previous studies.

The personal contact and direct dialogue during preoperative patient education is an essential cornerstone in the relationship between surgeons and patients and therefore cannot be replaced by any computer program independent of its level of quality. However, multimedia DVDs can be used as an effective and valuable tool supporting daily medical workflow.

References

  1. 1.
    Etchells E (1999) Informed consent in surgical trials. World J Surg 23(12):1215–1219. doi:10.1007/s002689900650 PubMedCrossRefGoogle Scholar
  2. 2.
    Kayser MC, von Harder Y, Friemert B, Scherer MA (2006) On informed patient consent. Chirurg 77(2):139–149. doi:10.1007/s00104-005-1101-3 PubMedCrossRefGoogle Scholar
  3. 3.
    Edwards MH (1990) Satisfying patients’ needs for surgical information. Br J Surg 77(4):463–465. doi:10.1002/bjs.1800770431 PubMedCrossRefGoogle Scholar
  4. 4.
    Askew G, Pearson KW, Cryer D (1990) Informed consent: can we educate patients? J R Coll Surg Edinb 35(5):308–310PubMedGoogle Scholar
  5. 5.
    Chan Y, Irish JC, Wood SJ et al (2002) Patient education and informed consent in head and neck surgery. Arch Otolaryngol Head Neck Surg 128(11):1269–1274PubMedGoogle Scholar
  6. 6.
    Lavelle-Jones C, Byrne DJ, Rice P, Cuschieri A (1993) Factors affecting quality of informed consent. BMJ 306(6882):885–890PubMedCrossRefGoogle Scholar
  7. 7.
    Hekkenberg RJ, Irish JC, Rotstein LE, Brown DH, Gullane PJ (1997) Informed consent in head and neck surgery: how much do patients actually remember? J Otolaryngol 26(3):155–159PubMedGoogle Scholar
  8. 8.
    Klima S, Hein W, Hube A, Hube R (2005) Multimedia preoperative patient information. Chirurg 76(4):398–403. doi:10.1007/s00104-004-0917-6 PubMedCrossRefGoogle Scholar
  9. 9.
    Luck A, Pearson S, Maddern G, Hewett P (1999) Effects of video information on precolonoscopy anxiety and knowledge: a randomised trial. Lancet 354(9195):2032–2035. doi:10.1016/S0140-6736(98)10495-6 PubMedCrossRefGoogle Scholar
  10. 10.
    Hermann M (2002) 3-dimensional computer animation—a new medium for supporting patient education before surgery. Acceptance and assessment of patients based on a prospective randomized study—picture versus text. Chirurg 73(5):500–507. doi:10.1007/s00104-001-0416-y PubMedCrossRefGoogle Scholar
  11. 11.
    Done ML, Lee A (1998) The use of a video to convey preanesthetic information to patients undergoing ambulatory surgery. Anesth Analg 87(3):531–536. doi:10.1097/00000539-199809000-00005 PubMedCrossRefGoogle Scholar
  12. 12.
    Chen HH, Yeh ML, Yang HJ (2005) Testing the impact of a multimedia video CD of patient-controlled analgesia on pain knowledge and pain relief in patients receiving surgery. Int J Med Inform 74(6):437–445. doi:10.1016/j.ijmedinf.2005.04.003 PubMedCrossRefGoogle Scholar
  13. 13.
    Yeh ML, Chen HH, Liu PH (2005) Effects of multimedia with printed nursing guide in education on self-efficacy and functional activity and hospitalization in patients with hip replacement. Patient Educ Couns 57(2):217–224. doi:10.1016/j.pec.2004.06.003 PubMedCrossRefGoogle Scholar
  14. 14.
    Kessler TM, Nachbur BH, Kessler W (2005) Patients’ perception of preoperative information by interactive computer program-exemplified by cholecystectomy. Patient Educ Couns 59(2):135–140. doi:10.1016/j.pec.2004.10.009 PubMedCrossRefGoogle Scholar
  15. 15.
    Danino AM, Chahraoui K, Frachebois L et al (2005) Effects of an informational CD-ROM on anxiety and knowledge before aesthetic surgery: a randomised trial. Br J Plast Surg 58(3):379–383. doi:10.1016/j.bjps.2004.10.020 PubMedCrossRefGoogle Scholar
  16. 16.
    Stergiopoulou A, Birbas K, Katostaras T, Diomidous M, Mantas J (2006) The effect of a multimedia health educational program on the postoperative recovery of patients undergoing laparoscopic cholecystectomy. Stud Health Technol Inform 124:920–925PubMedGoogle Scholar
  17. 17.
    Stergiopoulou A, Birbas K, Katostaras T, Mantas J (2007) The effect of interactive multimedia on preoperative knowledge and postoperative recovery of patients undergoing laparoscopic cholecystectomy. Methods Inf Med 46(4):406–409PubMedGoogle Scholar
  18. 18.
    Herrmann C, Brand-Driehorst S, Buss U, Ruger U (2000) Effects of anxiety and depression on 5-year mortality in 5,057 patients referred for exercise testing. J Psychosom Res 48(4–5):455–462. doi:10.1016/S0022-3999(99)00086-0 PubMedCrossRefGoogle Scholar
  19. 19.
    Williams OA (1993) Patient knowledge of operative care. J R Soc Med 86(6):328–331PubMedGoogle Scholar
  20. 20.
    Fell D, Derbyshire DR, Maile CJ et al (1985) Measurement of plasma catecholamine concentrations. An assessment of anxiety. Br J Anaesth 57(8):770–774. doi:10.1093/bja/57.8.770 PubMedCrossRefGoogle Scholar
  21. 21.
    Kulik JA, Mahler HI (1987) Effects of preoperative roommate assignment on preoperative anxiety and recovery from coronary-bypass surgery. Health Psychol 6(6):525–543. doi:10.1037/0278-6133.6.6.525 PubMedCrossRefGoogle Scholar
  22. 22.
    Ivarsson B, Larsson S, Luhrs C, Sjoberg T (2005) Extended written pre-operative information about possible complications at cardiac surgery—do the patients want to know? Eur J Cardiothorac Surg 28(3):407–414. doi:10.1016/j.ejcts.2005.05.006 PubMedCrossRefGoogle Scholar
  23. 23.
    McEwen A, Moorthy C, Quantock C, Rose H, Kavanagh R (2007) The effect of videotaped preoperative information on parental anxiety during anesthesia induction for elective pediatric procedures. Paediatr Anaesth 17(6):534–539. doi:10.1111/j.1460-9592.2006.02173.x PubMedCrossRefGoogle Scholar
  24. 24.
    Knobel A, Hassfeld S (2005) Preoperative information. Mund Kiefer Gesichtschir 9(2):109–115. doi:10.1007/s10006-005-0593-9 PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • D. Wilhelm
    • 1
    • 2
  • S. Gillen
    • 1
    • 2
  • H. Wirnhier
    • 2
  • M. Kranzfelder
    • 1
    • 2
  • A. Schneider
    • 2
  • A. Schmidt
    • 3
  • H. Friess
    • 1
  • H. Feussner
    • 1
    • 2
  1. 1.Department of Surgery, Klinikum r.d.IsarTechnische UniversitätMunichGermany
  2. 2.Workgroup for Minimal Invasive Therapy and Intervention (MITI), Klinikum r.d. IsarTechnische Universität MünchenMünchenGermany
  3. 3.Institute for media informaticsLudwig-Maximilian Universität MünchenMünchenGermany

Personalised recommendations