The term "clinical trial" used in this survey was not categorized by study design or funding body and thus, the definition of "clinical trial" in this survey included all randomized controlled trials, non-randomized trials, pharmaceutical-sponsored trials, and investigator-initiated trials.
Sepsis and shock definitions of trials completed before 1992 [ 31, 32, 38, 41, 43, 46] were generally consistent with definitions of the American College of Chest Physicians and Society of Critical Care Medicine Consensus Conference on sepsis and organ failure, albeit the two trials published in 1971 [ 41] and 1963 [ 32] used 'life threatening infections' as a criteria (Table 2).
Having established the definition of pilot trials as 'full trials in miniature' we next need to define the common subtypes of pilot trial, namely the internal and external pilot.
The five phases of the framework of Campbell et al [ 15] include 1) a pre-clinical or theoretical phase, 2) Phase I, identification of the components of the intervention, 3) Phase II, definition of the trial and intervention design, 4) Phase III, methodological issues for the main trial, and 5) Phase IV, promoting effective implementation of the intervention.
A precise definition of a trial's study population is important to assess whether results can be applied to other patients with the same condition.
Box 1 Definition of a clinical trial Clinical trial: A clinical trial is any research study that prospectively assigns human participants or groups of humans to one or more health-related interventions to evaluate the effects on health outcomes.
For example, David Sampson, one of the other review authors, stated: "In general, our definition of randomized trials was probably more inclusive than yours.
They should contribute to a better definition of clinical trials aiming at restoring pain control, genito-urinary functions and ultimately locomotion in paraplegic patients.
Some of the limitations of our study include the relatively arbitrary definition of large trials [ 16, 17] and the fact that our analysis pertains to a specific group of clinical investigators with activities restricted to the field of HIV infection.
