Non-invasive characterization of hemodynamics in adult out-of-hospital cardiac arrest patients soon after return of spontaneous circulation.

BACKGROUND

Little is known about hemodynamics in adult, out-of-hospital (OHCA) patients following return of spontaneous circulation (ROSC). A 1994 study when "high-dose epinephrine" use was common showed consistently elevated systemic vascular resistance (SVR) lasting ≥6 h in 49 adult patients after return of spontaneous circulation (ROSC).

STUDY AIM

To characterize hemodynamic abnormalities in adult OHCA patients soon after ROSC. Our hypothesis was that, unlike the consistently high SVR values reported when "high-dose" epinephrine was in common use, there would be a more heterogenous distribution of SVR values using current adrenergic therapy.

METHODS

We included adult, OHCA patients transported by paramedics to the Emergency Department (ED) post-ROSC. Children, prisoners, pregnant women, and those with ongoing CPR or arrest due to traumatic injury were excluded. Hemodynamics were recorded non-invasively as soon as feasible after ED arrival but were not used to influence therapy, which was guided by clinical judgment of treating ED physicians.

RESULTS

Hemodynamics were recorded on 30 patients 20 [16,25] minutes after ED arrival: 50% had a normal SVR, 30% had a high SVR, and 20% had a low SVR. There was no difference in survival to admission among groups, although there was a difference among groups in survival to discharge. Comparing the low SVR group vs the combined normal and high group revealed a trend for fewer 0/6 (0%) low vs. 10/24 (42%) normal or high SVR patients surviving to hospital discharge (p = .053).

CONCLUSION

A heterogeneous range of hemodynamic states exist post-ROSC rather than consistent vasoconstriction. Adequately powered, randomized clinical trials will be needed to determine whether noninvasively-derived, hemodynamic-directed therapy can play a role in improving neurologically-intact survival following OHCA in adults.