Impact of written information on knowledge and preferences for cardiopulmonary resuscitation

Previous research has found that 50%-80% of patients claimed awareness of CPR, but their knowledge was very limited and derived mainly from television dramas. Most patients believed erroneously that CPR is generally successful,^5,6 and both patients and health professionals were found to overestimate its success by up to 300%.⁷

We aimed to investigate knowledge of and attitudes to CPR among hospital inpatients and health professionals and to determine whether written information about CPR alters knowledge and preference for CPR. We have previously reported the opinions of patients and health professionals on the process of decision-making about CPR.⁸

• sociodemographic characteristics;

• sources of information on CPR (respondents could nominate as many as applied from a list of 11);

• whether each of 10 procedures is part of CPR (possible answers: yes, no or don't know);

• how successful CPR is in eight clinical scenarios, using a five-point scale: rarely (< 5%), seldom (5%-30%), sometimes (31%-60%), mostly (61%-90%) or almost always (> 91%); and

• whether respondents would like CPR performed on themselves in 12 specific clinical scenarios (possible answers: yes or no).

On completing the questionnaire, respondents were given a one-page information sheet that explained various aspects of CPR, including its definition, procedures that may or may not be considered part of CPR, risks and benefits, success rates, and prognostic indicators (good prognosis: after acute myocardial infarction; poor prognosis: cancer, severe infection, organ failure). Respondents were then asked to repeat the questions on knowledge and choices.

Knowledge of CPR was scored by allocating a point for each correct response. We assessed the relationship between this score and sociodemographic characteristics by standard multiple linear regression, with knowledge score as the dependent variable. For this analysis, we converted the discrete sociodemographic variable (health professional background) into a set of dichotomous independent variables using dummy variable coding (ie, doctors versus all other health professionals, and nurses versus all other health professionals). Significance of change in knowledge scores after provision of information was examined by one-way repeated-measures analysis-of-variance (ANOVA). As answers to some of the knowledge questions may be contentious (whether CPR involves intravenous drugs, intubation and defibrillation), analyses were repeated using scores with these questions omitted.

Composite "choice scores" about CPR were calculated by allocating a point for each condition in which the subject would choose to have CPR. The relationship between choice score, sociodemographic characteristics and knowledge score after provision of information was assessed by standard multiple linear regression, with choice score as the dependent variable and knowledge score and sociodemographic factors as independent variables. Significance of change in choice scores after provision of information was examined by ANOVA.

Knowledge before provision of information is shown in Box 2. Patients' knowledge scores were low (mean, 6.4 out of 18; 95% confidence interval [CI], 6.0-6.9), mainly because of lack of awareness of success rates of CPR, with 90% overestimating success for the "all patients" category. Health professionals' knowledge scores were higher than patients' (mean, 11.9; 95% CI, 11.7-12.1), but health professionals also overestimated success of CPR, with 65% overestimating success for "all patients". ANOVA showed that knowledge scores improved significantly after provision of written information for both patients and health professionals (patients: mean, 10.4; 95% CI, 9.9-11.1; health professionals: mean, 13.9; 95% CI, 13.7-14.2).

The only sociodemographic characteristics that significantly predicted knowledge scores before provision of information were age (for patients) and professional background (for health professionals): younger patients achieved higher scores than older patients, while doctors and nurses achieved higher scores than allied health professionals. Repeat analysis of the data after omission of contentious questions did not affect the relationship between sociodemographic variables and knowledge scores or the change in knowledge scores after provision of information.

CPR was chosen for more scenarios by patients who were younger or had lower knowledge scores and by health professionals who were younger, male, tertiary educated or had better self-reported health status.

Other studies have also found that patients are unaware of the procedures involved in CPR and, along with their relatives, generally overestimate success rates.¹⁰ This is not surprising, as television, books and magazines are often their most common sources of information. In addition, community education tends to be positive about CPR, often failing to describe its real success rates.

Several previous studies have investigated the relationship between choices about CPR and estimated probability of survival.^5,11 They found, similarly to us, that many patients change their minds about wanting CPR when they learn the true probability of survival. Furthermore, formal processes of information disclosure, including discussion of the likely outcome of resuscitation in specific clinical situations, has been shown to modify preferences for CPR.¹² In our study, the change in preference followed provision of a one-page information sheet. It is possible that a more optimal form of education (eg, repeated explanations tailored to the individual, with time for reflection and questions) would have produced a greater change in preferences.

Perceived morbidity after CPR also strongly influences many people's choices. A survey of 200 medical inpatients found that choice of CPR or DNR status was strongly influenced by anticipated outcome; 90% of patients desired CPR if they were to be restored to their normal health, 30% if the likely outcome after recovery was dependence, 15% if it was perceived as "hopeless", and 6% if it was coma.¹³ Other studies from the United States¹⁴ and United Kingdom¹⁵ have found that senile dementia, more than any other condition, is associated with a preference for DNR status. We found similarly that patients and health professionals would be unlikely to opt for CPR in the presence of brain injury or severe dementia. Nevertheless, as found by others,^6,10 some patients continued to opt for CPR even if they were likely to have a serious disability, such as coma or terminal illness.

We also found, in common with others overseas, that health professionals vastly overestimate the success rates of CPR. These rates (3%-30% in general hospitals) have not changed significantly in the past 30 years.^1,16 However, they are well below the rates perceived by physicians and nurses, who are responsible for making decisions about resuscitation status and informing patients and their surrogates.^17,18

There are several limitations to our study. Subjects included hospitalised patients with acute illness, and the findings may not be generalisable to other patient populations. The study instrument was a self-report questionnaire using hypothetical clinical scenarios; answers may not accurately reflect what individuals would choose in reality. However, the study has strengths; it assessed both knowledge of and attitudes to CPR in variable clinical contexts and included a formal assessment of competence (the MMSE). The study also used trained interviewers rather than clinicians to distribute questionnaires and so was less likely to introduce bias and perhaps more likely to elicit patients' true preferences.

As factors such as likelihood of survival and functional status after resuscitation may contribute to patients' wishes for CPR, it is ethically and clinically desirable that patients be provided with this information. Furthermore, the High Court of Australia has reaffirmed that patients must be given adequate information when making decisions concerning their healthcare.^19,20 It is also essential that health professionals who advise patients are aware of the real success rates of CPR. Otherwise, they have failed to meet the standards required both for ethical medical care and by law.²¹

Respect for autonomy demands that the views of patients or their surrogates should be sought in decision-making about CPR. Our study implies that patients understand and use prognostic information in their decision-making. For truly autonomous judgements, patients and health professionals clearly need better education on risks and benefits of CPR.

1. Robinson GR, Hess D. Post-discharge survival and functional status following in-hospital cardiopulmonary resuscitation. Chest 1994; 105: 991-994.
2. Landry FJ, Parker JM, Phillips YY. Outcome of cardiopulmonary resuscitation in the intensive care setting. Arch Intern Med 1992; 152: 2305-2308.
3. Rabkin MT, Gillerman JD, Rice NR. Orders not to resuscitate. N Engl J Med 1976; 295: 364-366.
4. Decisions relating to cardiopulmonary resuscitation. A statement from the British Medical Association and the Royal College of Nursing in association with the Resuscitation Council (UK). London: BMA, 1993.
5. Miller DL, Jahnigen DW, Gorbien MJ, Simbarti L. Cardiopulmonary resuscitation: how useful? Attitudes and knowledge of an elderly population. Arch Intern Med 1992; 152: 578-582.
6. Schonwefter RS, Walker RM, Kramer DR, Robinson BE. Resuscitation decision-making in the elderly: the value of outcome data. J Gen Intern Med 1993; 8: 295-300.
7. Potter JM, Stewart D, Duncan G. Living wills: would sick people change their minds? Postgrad Med J 1994; 70: 818-820.
8. Kerridge IH, Pearson SA, Rolfe IE, Lowe M. Decision making in CPR: attitudes of hospital patients and health care professionals. Med J Aust 1998; 169: 128-131.
9. SPSS. Statistical package for the social sciences. Version 6.0 for Windows. Chicago, Ill: SPSS Inc, 1990.
10. Schmerling RH, Bedell SE, Lilienfeld A, Delbanco TL. Discussing cardiopulmonary resuscitation: a study of elderly outpatients. J Gen lntern Med 1988; 3: 317-321.
11. Murphy DJ, Burrows MD, Santilli S, et al. The influence of the probability of survival on patients' preferences regarding cardiopulmonary resuscitation. N Engl J Med 1994; 330: 545-549.
12. Schonwetter RS, Teasdale TA, Taffet G, et al. Educating the elderly: cardiopulmonary resuscitation decisions before and after intervention. J Am Geriatr Soc 1991; 39: 372-377.
13. Frankl D, Oye RK, Bellamy PE. Attitudes of hospitalised patients toward life support: a survey of 200 medical inpatients. Am J Med 1989; 6: 645-648.
14. Ebell MH, Doukas DJ, Smith MA. The do-not-resuscitate order: a comparison of physician and patient preferences and decision-making. Am J Med 1991; 91: 255-260.
15. Robertson GS. Resuscitation and senility: a study of patients' opinions. J Med Ethics 1993; 19: 104-107.
16. Bedell SE, Delbanco TL, Cook EF, Epstein FH. Survival after cardiopulmonary resuscitation. Crit Care Med 1983; 309: 569-576.
17. Miller DL, Gorbien MJ, Simbarti LA, Jahnigen DW. Factors influencing physicians in recommending in-hospital cardiopulmonary resuscitation. Arch Intern Med 1993; 153: 1999-2003.
18. Wagg A, Kinirons M, Stewart K. Cardiopulmonary resuscitation: doctors and nurses expect too much. J R Coll Physicians Lond 1995; 29: 20-24.
19. Rogers v Whitaker (1992) 175 CLR 479.
20. Chappel v Hart [1998] HCA 55.
21. Wyong Shire Council v Shirf (1980) 146 CLR 40.

Reprints will not be available from the authors.
Correspondence: Dr I H Kerridge, Clinical Unit in Ethics and Health Law, Locked Bag 1, Hunter Region Mail Centre, Newcastle, NSW 2310.
Email: ikerridgATmail.newcastle.edu.au