title: Systemic reactions to tourniquet ischaemia.
abstract: In 15 patients, mean age 60 years, undergoing knee arthroplasty under lumbar epidural analgesia, changes in ECG, blood pressure, blood gases, serum potassium, acid-base status and serum creatine-phosphokinase were studied following release of a tourniquet applied for 70-135 min. During and after the ischaemia, the skin temperature of the leg operated on was monitored. Although dextran-70 was rapidly infused following tourniquet release, the blood pressure decreased significantly, due to a reduction in peripheral resistance. There were no signs of myocardial or pulmonary disturbances. Serum potassium in arterial blood increased significantly and reached a peak 3 min after tourniquet release. There was a tendency to metabolic acidosis, most pronounced after 3 min and caused by local lactate production. The skin temperature of the ischaemic leg fell progressively, which, combined with muscular relaxation, indicates a low metabolic rate. There was no evidence of local ischaemic muscular injury. It is concluded that the systemic changes after interruption of up to 2 h of tourniquet ischaemia are moderate and reversible, even in the elderly.
mesh_terms: D000136:Acid-Base Equilibrium; D000368:Aged; D000767:Anesthesia, Epidural; D001178:Arthroplasty; D001794:Blood Pressure; D002245:Carbon Dioxide / Q000097:blood; D002404:Catheterization; D003402:Creatine Kinase / Q000097:blood; D006801:Humans; D007511:Ischemia / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D007773:Lactates / Q000097:blood; D007866:Leg / Q000098:blood supply*; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D011188:Potassium / Q000097:blood; D012881:Skin Temperature; D014111:Tourniquets / Q000009:adverse effects*; D014655:Vascular Resistance
chemical_list: D007773:Lactates; D002245:Carbon Dioxide; D003402:Creatine Kinase; D011188:Potassium; D010100:Oxygen