Effect of epinephrine on cerebral and myocardial perfusion in an infant animal preparation of cardiopulmonary resuscitation.

Abstract

We assessed the efficacy of conventional cardiopulmonary resuscitation (CPR) in 2-week-old piglets. We determined intrathoracic vascular pressures, cerebral (CBF) and myocardial blood flows (MBF), and cerebral oxygen uptake during conventional CPR in this infant animal preparation and contrasted these results with those of previous work on adult animals. We further examined the effects of the infusion of epinephrine on these pressures and flows and on cerebral oxygen uptake, which has not been previously evaluated in adult preparations. Conventional CPR was performed on pentobarbital-anesthetized piglets with a 20% sternal displacement with the use of a pneumatic piston compressor. Chest recoil was incomplete, leading to an 18% to 27% reduction in anteroposterior diameter during the relaxation phase. Aortic and right atrial pressures in excess of 80 mm Hg were generated. These pressures are greater than those generally obtained in adult animals with similar percent pulsatile displacements. CBF and MBF were also initially greater than those reported in adult animals undergoing conventional CPR. However, when CPR was prolonged beyond 20 min, aortic pressure fell and CBF and MBF declined to the near-zero levels seen in adult preparations. At 5 min of CPR, CBF and MBF were 24 +/- 7 and 27 +/- 7 ml . min-1 x 100 g-1 (50% and 17% of the values during cardiac arrest), respectively. With the continuous infusion of epinephrine (4 micrograms/kg/min) in another group of animals, MBF was significantly greater at 20 min of CPR and CBF and cerebral O2 uptake were greater at 35 min of CPR as a result of higher perfusion pressures.(ABSTRACT TRUNCATED AT 250 WORDS)