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280 Use of the Abdominal Aortic Tourniquet to Reduce or Eliminate Flow in the Common Femoral Artery in Human Subjects

      Study Objectives

      Penetrating injuries of proximal femoral and iliac vessels are a common cause of death on the battlefield. Previous studies have shown that by applying between 80 to 140 pounds of pressure externally over the distal abdominal aorta, flow can be ceased in the common femoral artery. It has also been demonstrated that in a porcine model an externally applied pneumatic abdominal aortic tourniquet can occlude the aorta and inferior vena cava for 60 minutes without bowel injury or elevations of potassium. The objectives of this study were to: (1) determine if abdominal aortic tourniquet use in humans results in flow cessation in the common femoral artery, (2) measure the pressure required to cease flow in the common femoral artery, and (3) measure the discomfort associated with application of the abdominal aortic tourniquet.

      Methods

      This was a prospective trial to evaluate the pressure required to reduce and cease the blood flow in the common femoral artery in normal volunteers. Using a Phillips HDI 4000 and a linear array transducer, pulsed-wave Doppler measurements were taken in supine volunteers at the right common femoral artery just proximal to the bifurcation of the artery. The abdominal aortic tourniquet consisted of a inelastic belt with an integrated wedge-shaped bladder which could be inflated using a hand pump. The abdominal aortic tourniquet was placed just above the iliac crests with the wedge-shaped bladder over the anterior abdomen at the umbilicus. An integrated manometer was used to measure the pressure within the bladder as the bladder was inflated. Measurements of the Doppler flow in the common femoral artery were taken at baseline and repeated every 30 mmHg increase in the bladder pressure. Discomfort was measured using a verbal 10 point pain scale.

      Results

      In all (9/9) subjects flow was reduced in the common femoral artery with increasing bladder pressure from the abdominal aortic tourniquet. The arterial wave as measured by pulsed-wave Doppler transitioned from tri-phasic to bi-phasic at a median bladder pressure of 120mmhg (60-180), and from bi-phasic to mono-phasic at a median bladder pressure of 150mmhg (150-200). Flow ceased in 7 of 9 subjects at a median pressure of 180mmhg (150-230). Median discomfort at cessation of flow was 7 (3-10) which returned to 0 after device removal.

      Conclusion

      The abdominal aortic tourniquet device was effective at reducing flow in the common femoral artery and ceased flow in the majority of subjects. Application of the device was associated with discomfort that varied from moderate to severe and resolved with device removal.