Introduction:
Guidelines recommend dosing Epinephrine (Epi) at regular intervals during pediatric cardiac arrest, including patients requiring extracorporeal membrane oxygenation (ECMO). The impact of Epi-induced vasoconstriction on systemic afterload and veno-arterial ECMO support is poorly understood.
Hypothesis:
Higher total dose of Epi and shorter interval between Epi dose and ECMO flow during cardiac arrest will increase systemic afterload and interfere with ECMO support.
Methods:
This is an ancillary study to a single-center, retrospective observational study of patients 0-18 years old who required ECMO cannulation during resuscitation over a six-year period. Patients were excluded if ECMO was initiated prior to arrest or if the resuscitation record was incomplete. The primary exposure was time from last dose of Epi to initiation of ECMO flows; secondary exposures included cumulative Epi dose delivered and indexed to arrest time. Mean arterial pressure (MAP) and systemic vasodilator therapy were used as surrogates for systemic afterload; ECMO pump speed and vasoactive-inotrope score (VIS) were used as measures of ECMO support.
Results:
A total 92 events in 87 patients analyzed. The patient cohort was 53% female with median (IQR) age of 122 (30-478) days, weight 4.4 (3.3 - 8.7) kg, and 43% single ventricle physiology. On average, Epi was given 7 (4 - 10) times during a 35 (27 - 44) min arrest, for a total dose of 65 (37 - 101) mcg/kg; the last dose was given 6 (2 -16) min prior to the initiation of ECMO flows. In the 6 hours following initiation of ECMO, MAP increased from 42 (36 - 56) mmHg to 57 (47 - 70) mmHg, (p<0.0001). Shorter interval between last Epi dose and ECMO initiation trended with higher MAP after 1 hour of support (estimate -0.43, p=0.06) and associated with increased of vasodilators within 6 hours of ECMO (vasodilators used (1 - 6) vs not used 9 (3 - 16) min, p=0.05). No other associations were found between Epi delivery, MAP, vasodilator use, pump speed or VIS.
Conclusion:
There is limited evidence to support that regular dosing of Epi throughout a cardiac arrest is associated with clinically significant increases in afterload after ECMO cannulation. Additional studies are needed to validate findings against ECMO flows and clinically relevant outcomes.
Total-dose and SEU characterization of 0.25 micron CMOS/SOI integrated circuit memory technologies
