Informed consent in cardiac surgery: is it truly informed?

OBJECTIVE

To develop a validated questionnaire to measure how informed patients are when giving consent for elective coronary artery bypass grafting.

METHODS

We developed a questionnaire covering the domains described in the consent guidelines published by the General Medical Council. The questionnaire was developed for use in face-to-face interviews as opposed to a self-administered questionnaire. Interviews were conducted after the patients had given consent for surgery. A total of 41 patients were interviewed. To validate the questionnaire we tested the interobserver reliability by using four different interviewers and the construct validity by comparing it with area deprivation index and with predicted intelligence quotient scores obtained from the National Adult Reading Test.

RESULTS

The correlation of the ranking of the questions between the interviewers was satisfactory (Spearman's rank correlation coefficient, rs = 0.84-0.89). The total questionnaire scores correlated well with predicted intelligence quotient scores (rs = 0.48) but not with area deprivation index (rs = 0.01). Questions with the worst scores were those related to mortality, morbidity, alternative treatment options and their relative success rates and risks.

CONCLUSIONS

We have developed a validated questionnaire which tests patient's level of knowledge with respect to surgical myocardial revascularisation. Our study identified areas of informed consent where the minimal level of knowledge is below the recommended level. The questionnaire could be used in audits and clinical trials in patients undergoing coronary artery bypass grafting. It could be used as a tool to measure the effectiveness of patient education programmes. With appropriate changes, this instrument could also be applied in other fields of medical intervention, which require patients to give informed consent.