The relation of the post-ischemic reperfusion impairment to the severity of ischemia in the tibialis anterior muscle of the rat.
Hyperemic volume flow rates were followed during 15 minutes of post-ischemic reperfusion in tibialis anterior muscle of the rat after 1, 2 and 3 hours of tourniquet ischemia using the 133Xenon clearance technique. Results showed a no-reflow phenomenon after 2 and 3 hours of ischemia. There was a marked impairment in flow, seen immediately upon reperfusion as a reduction or abolishment of the initial peak of the normally brisk post-ischemic hyperemia. The impairment increased with increasing duration of ischemia. The range of maximal peak hyperemic flow rates was wide and median maximal peak flows were 43.1, 14.6 and 7.2 ml.min-1.100 g-1 after 1.2 and 3 hours, respectively. This reflow impairment was not caused by differences in arterial blood pressure at the start of perfusion or during the initial 2 minutes of perfusion. Venous hematocrit at the start of the reperfusion was not significantly different between the three groups. Total muscle water of 75.9% in control muscle increased to 79.7% after 3 hours of ischemia and 1 hour of reperfusion and reached a maximum of 85.7% after 5 hours of reperfusion, demonstrating that the no-reflow seen during the initial 15 minutes could not be caused by an increased tissue pressure due to rapidly developing reperfusion edema. Results indicate a microvascular hindrance in post-ischemic reperfusion.
Gidlöf
A
A
Clinical Research Center, Faculty of Health Sciences, University Hospital, Linköping, Sweden.
Lewis
D H
DH
D000818:Animals; D001794:Blood Pressure; D005260:Female; D007511:Ischemia / Q000503:physiopathology*; D008833:Microcirculation / Q000503:physiopathology; D009132:Muscles / Q000098:blood supply*; D051381:Rats; D011919:Rats, Inbred Strains; D012039:Regional Blood Flow; D015427:Reperfusion Injury / Q000503:physiopathology*; D014111:Tourniquets