A study of participants in a clinical trial at a Swiss intensive care unit has thrown some doubt on whether current informed consent procedures really protect patients’ autonomy and rights in the emergency setting.

The study, published in the journal Critical Care, was conducted by Catherine Chenaud and colleagues from the University Hospital of Geneva. They followed up 44 ICU patients who had given their informed consent to take part in a clinical trial on inflammatory responses. A previous study by the same researchers had shown that 22% of ICU patients could not recall taking part in a clinical trial, despite having given their informed consent before admission to the unit, and 25% were unable to remember the purpose and risks of the trial.

While ICU patients may have limited capacity for comprehension, lighter sedation permits an increasing number of them to remain conscious, Chenaud et al note. These patients “seem to be able to understand the information presented and to decide freely if they would like to participate in the study," they add.

In the latest study, eligible patients admitted to the ICU after major surgery or trauma had to present with a Glasgow Coma Scale score of 15, to be fully oriented and free of mechanical ventilation, as well as judged competent by both the investigator and the attending physician.

The investigators obtained informed consent according to a protocolled procedure, following a 20-minute individual oral presentation that explained the trial with emphasis on two components: its purpose and the related risks (which were minimal). The patients were also given a one-page information leaflet and asked whether they had any questions about the trial before signing the informed consent form.

Little recollection of risks

Interviewed by the same investigator 10-12 days later, 35 of the 44 (80%) patients recognised they had taken part in the clinical trial but only 14 (32%) could remember the purpose and risks. More of these ‘complete recall’ patients had read the information leaflet or asked at least one question before signing the informed consent form (13 out of 14) than those with ‘incomplete recall’ (18 out of 30).

The low level of complete recall in the trial, compared with the 75% previously recorded in an “ideal situation” where consent was obtained prior to admission to the unit, revives the debate about obtaining consent in ICUs, the authors comment. In the past, deferred consent or waivers were considered acceptable for some research in emergency settings. In the last few years, though, legislation has sought to enhance protection for incompetent patients and barriers to inclusion of ICU patients in research studies have grown, they point out.

The study results reinforce the importance of treating informed consent as an ongoing process rather than a single procedure, and the need to revisit informed consent several times over the course of a trial, Chenaud et al say. Investigators should keep reiterating trial information to ICU patients even after their stay has ended and should reassess on a regular basis whether continued participation in the trial is what the patient wants, they suggest.By Peter Mansell