"Resuscitation time bias"-A unique challenge for observational cardiac arrest research

Resuscitation. 2018 Apr;125:79-82. doi: 10.1016/j.resuscitation.2018.02.006. Epub 2018 Feb 6.


Observational studies are prone to a number of biases. One of these is immortal time bias. In this manuscript, we discuss immortal time bias as it pertains to post-cardiac arrest research and describes a related bias which we term "resuscitation time bias". This bias can occur when studying exposures during cardiac arrest. In this unique situation, an exposure is more likely to occur the longer the cardiac arrest continues. Since length of resuscitation is strongly associated with worse outcome, this will bias the results toward a harmful effect of the exposure. We discuss this bias and present methods to account for it.

Keywords: Bias; Epidemiology; Immortal time bias; Resuscitation.

MeSH terms

  • Bias
  • Cardiopulmonary Resuscitation / methods*
  • Heart Arrest / mortality
  • Heart Arrest / therapy*
  • Humans
  • Observational Studies as Topic
  • Risk Assessment
  • Time Factors