• Adenosine;
  • coronary circulation;
  • hypotension;
  • controlled;
  • nitroprusside

The effects of adenosine and sodium-nitroprusside (SNP) on central and myocardial haemodynamies and metabolism were evaluated during fentanyl anaesthesia (100 μg kg-1) in six patients with peripheral vascular disease. The investigation was performed during stable anaeshtesia, before scheduled abdominal aortic graft surgery. Adenosine and SNP were infused intravenously in random order over 20 min, leaving a 30-min control period in between. The vasodilators were titrated in order to reduce mean arterial pressure by approximately 25%. Adenosine (90 20 μgkg-1 min-1) reduced mean arterial pressure from 10.9 0.3 to 8.4 0.4 kPa (82 3 to 63 3 mmHg), and SNP (0.7 0.1 μg kg-1 min-1) from 11.0 0.2 to 8.4 0.3 kPa (83 3 mmHg to 63 3 mmHg) during the hypotension period. Cardiac index remained unaffected during induced hypotension with both vasodilators, while heart rate increased during SNP infusion (8 3d̀) and remained unaffected with adenosine. Left ventricular stroke work index and myocardial oxygen consumption decreased during SNP infusion (33 3% and 17 5%, respectively), while these parameters were unchanged with adenosine. Adenosine hypotension increased coronary sinus flow 1–2 fold (128 26%), together with increased coronary sinus oxygen content (96 11%). In contrast, coronary sinus flow decreased during SNP hypotension (– 15 4%) with unaffected coronary sinus oxygen content. It is concluded that adenosine, in contrast to SNP, is associated with a hyperkinetic myocardial circulation.