Reply

Abstract

letter I concerning patient recruitment for clinical research raises some interesting points concerning the time at which informed consent should be obtained and the implications of a "no exclusion" clause in a clinical research protocol.We assume that the protocol was approved by the institutional ethics committee, although this is not stated in the letter. Were the three ocular block techniques for cataract surgery all commonly used? If so, they were not experimental techniques. If these assumptions are correct, the consent given by patients should have been only for collection and analysis of aggregate data for publication. Consent, either verbal or written, to have surgery performed under ocular block would have been obtained at the same time, and we are told that patients were made aware of the study by the surgeon. The informed consent for research, obtained shortly before anaesthesia and surgery, therefore refers to data collection concerning efficacy of the block rather than its performance.We have never encountered a "no exclusion" clause in a study protocol and we are not sure what this could mean. The standard of care provided to patients must never be influenced by their decision to participate or not in a study protocol. Did all patients agree to participate and, if not, did they still have one of the three ocular blocks and their cataract surgery? The decision of the anaesthetist to proceed with the block in the patient described should have been based entirely on clinical criteria. We do not understand how postponement of surgery could have put the study at risk. The request of the patient, through his son, to proceed with the block and surgery was presumably because the patient wanted his vision restored and had nothing to do with the research protocol.If there is a language barrier, the investigator, aided by an interpreter, must be satisfied that the patient understands what is entailed. The essential points to be covered include the reasons for the study, research techniques including randomization, anticipated benefits and consequences, foreseeable risks, maintenance of confidentiality of subjects, anticipated time commitment, and the right to withdraw from the study at any time and without penalty. 2 If the investigator has any doubts about the patient's ability to comprehend, the patient must not be enrolled and this should have no consequences for the patient's medical care.