An epidemiologist's review of the case for pulsatile flow during cardiopulmonary bypass.

Not all science is created equally. New evidence is created daily, albeit of varying quality. Quality may be assessed on a number of fronts, although I approach my assessment of quality broadly. My earlier claim is not solely based on study design but on methodology and analytic approach. The foundational knowledge supporting pulsatile flow during cardiopulmonary bypass is not immune to this data quality. There are a number of articles supporting vs. discounting the use of pulsatile flow in this setting. However, there are inherent flaws in many of these. In this manuscript, I shall focus my attention on statistical power and sample size as it relates to the evidence base for pulsatile flow during cardiopulmonary bypass.