ECMO-/ECLS

appropriateness of the control group in the trial; specifically, did the control group
receive routine care as it is practiced at your hospital? For example, if your ICU
routinely maintains blood glucose <150 and a RCT of glycemic control demonstrates
that an intervention group with blood glucose <90 did better than a “control group” with
blood glucose <200, should your ICU change your practice to maintain blood glucose
<90? If the control group in a RCT is not reflective of usual care in clinical practice, then
the results of the trial cannot be assumed to better than usual care [ 18 - 21 ]. Many
landmark RCT trials in critical care have utilized control groups not reflective of usual
care, thereby limiting the validity of their conclusions and generalizability [ 1 , 17 - 27 ].
Furthermore, the treatment effects in a RCT may not be reproducible outside of the trial
setting. This was demonstrated with APC in which phase IV post-marketing studies
showed higher rates of bleeding complications with smaller improvements in mortality
[ 15 , 17 , 28 ].
Further available types of clinical research include systematic reviews and expert
consensus guidelines. Systematic reviews are literature reviews about a particular
treatment that will use techniques of meta-analysis to understand the effectiveness of a
therapy across multiple studies. These reviews can provide measures of the
consistency of the treatment effects of a therapy across studies, insights into why
different trials had varying results, and when appropriate, combine the results of the
individual studies to provide an overall estimate of the treatment effect of a therapy [ 9 ,
10 , 27 ]. Expert consensus guidelines are becoming more common in critical care with
multiple guidelines being developed and sponsored by medical societies such as the
Society of Critical Care Medicine, American Thoracic Society, American College of