PLASMA ENDOTHELIN FOLLOWING CARDIAC-ARREST - DIFFERENCES BETWEEN SURVIVORS AND NONSURVIVORS

Cardiac arrest is associated with major metabolic disturbances, includ ing severe hypoxia and large increases in circulating catecholamines, both of which are known to stimulate generation of the potent endothel ium-derived vasoconstrictor peptide endothelin-1. We have, therefore, examined plasma immunoreactive endothelin concentrations following car diac arrest. Blood was sampled at 10-min intervals from a central veno us catheter inserted at onset of resuscitation in 38 patients (13 fema le; mean age, 67 years) presenting with cardiac arrest to the Accident and Emergency Department at the Royal Infirmary of Edinburgh. Plasma immunoreactive endothelin concentrations (mean +/- S.D.) in patients f ollowing cardiac arrest (5.4 +/- 2.3 pg/ml) were no different from tho se in healthy subjects (5.1 +/- 1.2 pg/ml). There was no significant d ifference between endothelin concentrations at presentation in survivo rs and non-survivors of cardiac arrest. However, non-survivors had a s ignificant fall in endothelin concentrations with time from onset of r esuscitation from 5.4 +/- 2.2 pg/ml to 3.5 +/- 1.8 pg/ml (P = 0.002), while survivors had a nonsignificant increase in concentrations. On mu ltiple regression analysis there was a significant association between higher plasma endothelin concentration and survival (r = 0.37; P = 0. 009). The failure of plasma endothelin to increase after cardiac arres t is unexpected. Although the fall in plasma endothelin with time in n on-survivors may reflect the adverse physiological milieu that occurs during cardiac arrest, it is also possible that low endothelin concent rations contribute to the poor prognosis in this condition.