Maldistribution of heterogeneous coronary blood flow during canine endotoxin shock

Study objective – The aim was to investigate whether heterogeneous coronary blood flow is mal-distributed during endotoxin shock. Design – Variables were studied before (t = 0) and at t = 90 and t = 120 min after bolus injection of saline (n = 6) or endotoxin (n = 6). Subjects – 12 anaesthetised mongrel dogs, weight 20-27 kg, were used. Measurements and main results – We studied myocardial blood flows in small tissue sections (of about 1 g in left and 2 g in right ventricle) with radioactive microspheres, together with haemody-namic variables and global myocardial metabolism. At t = 0 min in controls, regional flows per 100 g were heterogeneous and ranged from a factor 0.2 to 2.7 and 0.6 to 1.6 of mean flow per 100 g to the left and right ventricle respectively; heterogeneity was unchanged at t = 90 and t = 120 min. Between t = 0, t = 90, and t = 120 min regional flows correlated: r = 0.78(SD 0.14), n = 18, for left ventricle, and r = 0.70(0.17) for right ventricle. In the endotoxin group, cardiac output and mean arterial pressure decreased by 44(7) and 48(11)% respectively, and lactate increased by 3.2(0.6) mmol·litre−1 at t = 120 min. Global left ventricular blood flow and delivery and metabolism of 02 were unchanged; lactate extraction and external work fell. The ratio between global right ventricular 02 delivery and external work also rose. Regional blood flows ranged from a factor 0.2 to 2.7 and 0.1 to 1.8 of mean flow to left and right ventricles respectively; heterogeneity did not differ from controls and did not change with time. Flow correlations with time were reduced: 0.45(0.24) for left ventricle and 0.45(0.26) for right ventricle (both n = 18, p