Background: Synergistic effects of adrenaline (epinephrine) and vasopressin may be beneficial during cardiopulmonary resuscitation. However, it is unknown whether either adrenaline alone or an alternating administration of adrenaline and vasopressin is better for restoring vital organ perfusion following basic life support (BLS) according to the revised algorithm with a compression-to-ventilation (c/v) ratio of 30:2. Material and methods: After 4 min of ventricular fibrillation, and 6 min of BLS with a c/v ratio of 30:2, 16 pigs were randomised to receive either 45 mu g/kg adrenaline, or alternating 45 mu g/kg adrenaline and 0.4 U/kg vasopressin, respectively. Results: Coronary perfusion pressure (mean +/- S.D.) 20 and 25 min after cardiac arrest was 7 +/- 4 and 5 +/- 3 mm Hg after adrenaline, and 25 +/- 2 and 14 +/- 3 mm Hg after adrenaline/vasopressin (p < 0.001 and <0.01 versus adrenaline), respectively. Cerebral perfusion pressure was 23 +/- 7 and 19 +/- 9 mm Hg after adrenaline, and 40 +/- 10 and 33 +/- 7 mm Hg after adrenaline/vasopressin (p < 0.001 and <0.01 versus adrenaline), and cerebral blood flow was 30 +/- 10 and 27 +/- 11 % of baseline after adrenaline, and 65 +/- 40 and 50 +/- 31% of baseline after adrenaline /vasopressin (p < 0.05 versus adrenaline), respectively. Return of spontaneous circulation (ROSC) did not differ significantly between the adrenaline group (0/8) and the adrenaline/vasopressin group (3/8). Conclusion: Adrenaline/vasopressin resulted in higher coronary and cerebral. perfusion pressures, and cerebral blood flow, while ROSC was comparable. (C) 2007 Elsevier Ireland Ltd. All rights reserved.