The combination of propranolol, hyaluronidase, and nitroglycerin significantly reduced the rise in intramural carbon dioxide tension during coronary occlusion to 22.0 mm Hg compared to 53.1 mm Hg in controls (P<0.01).
Do interventions like propranolol, hyaluronidase, and nitroglycerin reduce ischemic injury as measured by intramural carbon dioxide tension in a dog model of coronary occlusion?
Direct measurement of intramural carbon dioxide tension demonstrates that propranolol, hyaluronidase, and nitroglycerin individually and additively reduce ischemic injury during coronary occlusion in a canine model.
Absolute Event Rate: 22% vs 53.1%
p-value: p=<0.01
Although numerous interventions have been shown to exert a salutary effect on the ischemic myocardium, the severity of ischemia generally has been measured by indirect techniques. In the present investigation the effect of ischemia on intramural carbon dioxide tension (PmCO(2)) was measured directly in the open-chest, anesthetized dog with a mass spectrometer during repetitive 10-min coronary artery occlusions separated by 45-min periods of reflow; simultaneously, regional myocardial blood flow in the ischemic area was measured by (127)Xenon washout. In all dogs the increase in PmCO(2) from before to 10 min after the first occlusion (DeltaPmCO(2)) exceeded that during subsequent occlusions. In those dogs not receiving an intervention (controls), DeltaPmCO(2) during the third occlusion was similar to that during the second occlusion. When propranolol, hyaluronidase, and nitroglycerin were administered to different groups of dogs before the third occlusion, each caused significantly smaller elevations in DeltaPmCO(2) than those occurring during the control second occlusion, and the combination of all three interventions induced the smallest increase in DeltaPmCO(2). Regional myocardial blood flow rose with hyaluronidase and was unchanged with propranolol, nitroglycerin, and the three drugs in combination. In contrast to these beneficial interventions, isoproterenol infused with the third occlusion caused a higher DeltaPmCO(2) than during the control second occlusion. It is concluded, first, that interventions that modify the severity of ischemia can be evaluated by measuring intramural carbon dioxide tension; second, that propranolol, hyaluronidase, and nitroglycerin reduce ischemic injury, whereas isoproterenol increases it; and third, that the combination of propranolol, hyaluronidase, and nitroglycerin exerts an additive beneficial effect on ischemia.
Hillis et al. (Mon,) conducted a other in Myocardial ischemia (n=52). Propranolol, hyaluronidase, nitroglycerin, and their combination vs. No intervention (control) was evaluated on Increase in intramural carbon dioxide tension (ΔPmCO2) during the third coronary artery occlusion (in mm Hg) (p=<0.01). The combination of propranolol, hyaluronidase, and nitroglycerin significantly reduced the rise in intramural carbon dioxide tension during coronary occlusion to 22.0 mm Hg compared to 53.1 mm Hg in controls (P<0.01).
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: