Abstract
Clinical research remains a vital contributor to medical knowledge, and is an established and integral part of the practice of medicine worldwide. Respect for patient autonomy and ethical principles dictate that informed consent must be obtained from subjects before they can be enrolled into clinical research, yet these conditions may be difficult to apply in real practice in the intensive care unit (ICU). A number of factors serve to complexify the consent process in critically ill patients, notably decisional incapacity of the patient due to illness or sedation. Obtaining consent for research from a designated proxy or family member, commonly termed a "surrogate decision maker" (SDM) may be difficult, since SDMs dealing with the emotional, psychological and logistic impact of a sudden hospitalisation of their loved-one are not always receptive to the idea of research or emotionally equipped to reflect rationally on the opportunities being proposed to them. In addition, time constraints and workload pressures on the attending physician may render consent opportunities unfeasible, and the resulting loss of eligible patients could represent a bias in clinical trials, or limit the generalizability of their results. Alternative procedures such as deferred or waived consent have been used in the past and may be suitable alternatives in certain conditions, provided appropriate approval from institutional review boards (IRBs) can be obtained, in accordance with existing legislation. Some of the main questions inherent to the conduct of clinical research in critically ill patients are discussed in this review.