Hemodynamic Effects of Arterial Vs. Venous Legs Compression in Normal Volunteers

Introduction: Compression of the legs narrows the blood vessels and reduces their blood volume, provided the compression pressure is greater than the intravascular pressure.In this study we tested the hypothesis that compressing all the blood vessels of the legs, including the arteries enhances the hemodynamic parameters of normotensive volunteers better than venous compression only. Methods:The study was approved by the Eisenhower Medical Center IRB.After signing an informed consent, 35 Volunteers were screened by physical exam and legs Doppler ultrasound to rule out DVT.They were studied on two occasions, two weeks apart.On both tests, echocardiography cardiac output (CO) and stroke volume (SV), mean arterial blood pressure (MAP) and heart rate (HR) were measured before (baseline) and just after (T1), 5 minutes after (T5) and 10 minutes after (T10) application of either an arterial compression device applying 150 mm Hg on the limb (Auto-transfusion tourniquet, A-TT), or a venous compression device applying 30-70 mm Hg on the limb (ZOEX, LIFE Wrap).Results: All subjects were free of DVT and included in the study.Baseline values were the same between the first and the second test-day.Tests done with the ZOEX venous compression showed unchanged MAP and HR and slightly reduced CO and SV.MAP of subjects tested with A-TT increased from 78+11 mm Hg at Baseline to 90+11 mm Hg (p<0.001) at T1 and CO increased from 4.8+1.0l/min at Baseline to 6.3+0.95l/min at T1. HR slightly decreased with ZOEX application and slightly increased with A-TT use.All subjects rated the A-TT discomfort as higher than that of the ZOEX.Discussion: Vascular compression of the legs causes complete emptying of the blood vessels (arteries, veins, capillaries) if the subject's systolic blood pressure is below 150 mm Hg and blocks the blood return to the legs thereby increasing blood pressure and cardiac output.Conversely, venous compression of normotensive subjects lacks these effects. Conclusion:Arterial compression with auto-transfusion tourniquet enhances the hemodynamic status of normotensive subjects with systolic blood pressure less than 150 mm Hg.Additional studies in emergency care of hypotensive patients are indicated.