Abdominal aortic tourniquets have been around as an idea for a hundred years but still haven’t been accepted as mainstream trauma care. A small study on volunteers in military medicine tests one of these devices. They seem to work.
IEDs caused the majority of losses in the wars in Iraq and Afghanistan. While there have been advances in helmet and body armour design, the lower limbs, groin and pelvis remain relatively exposed.
Consequently injuries in the lower limbs and pelvis have become more common. Haemorrhage from junctional parts, the pelvis and the groin have emerged as leading killers.
This is why designs like the Abdominal Aortic Tourniquet has received attention from military docs and medics.
It is designed to compress the aorta at the level of the umbilicus thereby preventing infraumbilical blood flow and hopefully buying the time the victim needs to get to definite treatment.
In the image to the right the AAT is mounted on top of a standard pelvic binder demonstrating how they don’t interfere with each other. The AAT is basically a girdle with a windlass and then an inflatable balloon.
The study was conducted by the UK Royal Army Medical Corps. 16 healthy, young serving soldiers volunteered for the study. The AAT was applied and then inflated until femoral blood flow stopped according to doppler ultrasound or until a maximum pressure limit of 300 mmHg was reached.
Femoral blood flow ceased completely in 15 of the 16 volunteers. In one subject it didn’t work as intended. That volunteer had a height, weight, girth and BMI greater than average. He also reported a pain score that was higher than the average. The authors speculate that abdominal wall tension, due to the volunteer being uncomfortable, could have contributed to failure. The authors also speculate that this would be less of an issue in anesthesised, shocked or unconscious patients.
This is data suggesting the abdominal tourniquet principle is useful. For me, this is relevant in pelvic trauma, untourniquetable lower limb bleeds or in gyn/obs bleeds. Traditionally, external aortic compression is achieved by putting a knee or fist in the groin with all your body-weight on it. A made-for device could do this job better (especially in prehospital care or retrieval). I am surprised these devices haven´t entered the mainstream yet.