Objective: To determine whether gastric intramural pH (pHi), an indirect measure of gastric mucosal ischemia, can be used to predict the success of weaning from mechanical ventilation. Gastric muco...

Gastric Intramural pH as a Predictor of Success or Failure in Weaning Patients from Mechanical Ventilation

Throughout the last decade, multiple interventions have been shown to decrease myocardial ischemic injury and limit infarct size in animal models of acute myocardial infarction. Results of...

Efforts to Limit the Size of Myocardial Infarcts

Background Interleukin-8 (IL-8) secreted from endothelial cells is a powerful neutrophil chemoattractant and activator. We hypothesized that human endothelial cells deprived of oxygen would secrete...

Ischemia-Induced Interleukin-8 Release After Human Heart Transplantation: A Potential Role for Endothelial Cells

The effect of hyaluronidase on myocardial ischemic injury was examined in 13 patients with acute myocardial infarction, and the results were compared with 11 patients who did not receive h...

Effects of Hyaluronidase Administration on Myocardial Ischemic Injury in Acute Infarction

https://www.amjmed.com/article/0002-9343(83)91127-0/pdf

Role of beta-adrenergic blockade in the therapy of patients with myocardial infarction

The present study was performed to evaluate the usefulness of changes in intramural oxygen (PmO2) and carbon dioxide (PmCO2) tensions shortly after coronary artery occlusion as indices of the severity of myocardial ischemic injury. In 14 open-chest, anesthetized dogs, a 60-min coronary artery occlusion was performed, during which PmO2 and PMCO2 were measured continuously with a mass spectrometer. Regional myocardial blood flow (RMBF) adjacent to the mass spectrometer probes was measured by the xenon-127 washout technique both before and 30 min after coronary artery occlusion. At the end of 60 min of occlusion, the dogs were killed, and biopsies for histological examination of 1-micron-thick sections were obtained from the tissue surrounding each mass spectometer probe. The decline in PmO2 during the 60-min occlusion bore no relationship either to the severity of ischemic injury as assessed by histological examination, or to the reduction of RMBF. In contrast, the magnitude of rise in PmCO2 during the 60 min of occlusion corresponded closely to both the severity of injury assessed histologically and the reduction of RMBF.

Intramural PCO2: a reliable index of the severity of myocardial ischemic injury.

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.

https://dm5migu4zj3pb.cloudfront.net/manuscripts/109000/109284/JCI79109284.pdf

Assessment of the efficacy of interventions to limit ischemic injury by direct measurement of intramural carbon dioxide tension after coronary artery occlusion in the dog.

D. E. Tow

Papers

Intramural PCO2: a reliable index of the severity of myocardial ischemic injury.

Assessment of the efficacy of interventions to limit ischemic injury by direct measurement of intramural carbon dioxide tension after coronary artery occlusion in the dog.