Friday, November 18, 2022

Post-Cardiac Arrest Hypotension

Taming The SRU - November 18, 2022 - By Kletzel Max 
Ref: Bougouin W, Slimani K, Renaudier M, et al. Epinephrine versus norepinephrine in cardiac arrest patients with post-resuscitation shock. Intens Care Med 2022;48(3):300–10. 10.1007/s00134-021-06608-7
This was a large cohort study that found an increase in all-cause mortality, as well as cardiovascular-specific mortality and poorer neurological outcomes, amongst post-ROSC patients receiving an epinephrine infusion for post-resuscitation shock. Physiologically, this can likely be explained by the pro-arrhythmogenic properties of a beta-adrenergic medication acting on a stunned myocardium. Furthermore, the alpha-adrenergic properties of norepinephrine likely mitigate the sepsis-like vasoplegic state seen in the post-ROSC period, without irritating the already dysfunctional heart tissue. Nonetheless, it is difficult to generalize these results to US population where survival of OHCA to hospital discharge is approximately 7%, compared to 30% reported in this European study.(4) Furthermore, despite the propensity analysis, it is difficult to ignore the glaring characteristic differences between the epinephrine and norepinephrine groups and question the presence of underlying confounders. Overall, this study certainly makes one think twice before reflexively reaching for an epinephrine infusion in a patient who recently achieved ROSC and is now exhibiting signs of shock. Yet more definitive data, and especially a randomized control trial, is needed before this ongoing debate is settled. Until then, clinicians will likely continue to rely on the clinical data available to them, including vital signs, EKG, and bedside ultrasound, when choosing the ideal vasopressor for combating post-ROSC shock.