Bleeding Control: Tourniquets & PASGs

I often lecture on the controversies in prehospital care and thought I’d share some controversies surrounding the equipment used and what might be used in the future.

For most of our careers, tourniquets have always been described as being a last resort bleeding control appliance. We were even discouraged from using them as they contribute to the death of the limb to which they are applied. Recently however, research published on the benefits of tourniquets is causing us to take another look at the ancient remedy.

Battlefield situations are always a fertile ground for producing data on treating casualties. Military medics use tourniquets as a first-line bleeding control implement when under fire. As they are often not in a position to provide direct pressure, medics in battlefield situation are using tourniquets to control bleeding until they can get the casualties to definitive care or at least to a place where direct pressure can be applied.

As I mentioned above, the concerns surrounding tourniquet use focused on possible complications. Nerve, or muscle damage due to loss of blood flow or compression caused by the device are complications that are measured against the benefit of bleeding control.

Tourniquets In Surgery

It’s important to note that tourniquets have been used safely for years in surgery allowing for bloodless operations. The preferred type are pneumatic devices, working like a blood pressure cuff, but cravat or strap types can be used effectively as well. The numbers from the military are encouraging, with reports of seven out of 10 deaths prevented.

Tourniquets should be placed just proximal or above the wound, and are traditionally not used below the elbow or knee. As expected, studies have shown that the pressure required to stop the bleeding increases with the size and width of the limb. It is important that tourniquets be sufficiently tight. If only venous blood flow is restricted, and not arterial, the bleeding can actually get worse.

It’s also important to remember that direct pressure is still the front line and most preferred bleeding control method. It is, by far, the best method and doesn’t have significant complications.

However, recent research is suggesting that elevation, a long-used method to assist bleeding control, doesn’t help. Pressure points can be some help, but direct pressure is the best method.

As for tourniquets, always follow protocols, but feel better about using them when there is no other option, and continue to look for more definitive protocols for tourniquet use based on the forthcoming military data.

A newer development in bleeding control is hemostatic dressings or applications. These are dressings or powders that can be applied to wounds that decrease or stop the bleeding. These also are being tested extensively in the military with generally good results. The only possible detractor is that at least one of the hemostatic applications causes an exothermic reaction that can cause burns if not used correctly.

Hemostatic Dressings

The results on hemostatic dressings from the battlefield are good, but it is important to note that the evidence to date does not suggest these are better than direct pressure. Remember, on the battlefield, we’re talking about live fire when direct pressure may not be possible. A battlefield is nothing like what we face when civilians are injured.

Over the years, I’ve talked a lot about pneumatic anti-shock garments (PASGs) and some of you may have seen my articles and lectures on the topics. PASGs, which were formerly called military anti-shock trousers (MAST), have applications in the field. I feel they are useful in situations where there are no other options for helping the patient.

PASGs were designed using the G-suit concept. G-suits were designed for pilots to counteract G forces experienced in fighter jets. G forces in those jets can be so strong that they prevent adequate blood flow to the brain causing unconsciousness.

The military has always looked for bleeding control options in an effort to prevent casualties bleeding to death before they can get to definitive care.

They applied the G-suit concept to trousers with air bladders that when filled would compress the injuries in bleeding soldiers. They tested it in dog labs and on the battlefield, and were pleased with the results.

Following the success on the battlefields, civilian variations became available just as emergency medical service systems organized in the United States and prehospital care training was available to providers.

MAST Suits

The “MAST” suit became a required piece of equipment on all U.S. ambulances. Originally used for bleeding within the limits of the areas covered by the suit, EMTs quickly adapted to suit to use from everything from fractures to full arrest victims.

After decades of use, studies show that in some cases use of the MAST suit might be harmful, which caused it to fall into disfavor. Some protocols still call for PASGs or MAST suits to be used for pelvic fracture management, but many emergency medical technicians may not know this protocol, or how to use one if they have it.

The PASG is the most studied piece of prehospital equipment in existence. The National Association of Emergency Medical Service Physicians drafted a position paper for its use after reviewing over 100 studies.

At the beginning of the position paper they made the following statement; “Ironically, widespread condemnation of the PASG took place in the absence of scientific validation that it was detrimental in all situations. Negative outcomes in a limited number of restricted applications have been extrapolated to the broad gamut clinical situations. EMS providers should still be taught that the PASG is an acceptable treatment modality, and the medical direction may or [may] not elect to use it.”

Physicians’ Synopsis

The physicians then made recommendations for its use and here’s a brief synopsis of what they said based on the literature.

PASGs are useful: for pelvic injuries with hypotension; hypotension due to ruptured abdominal aortic aneurisms (AAA); severe traumatic hypotension; uncontrollable hemorrhage of the lower extremities; and anaphylactic shock in patients unresponsive to standard therapy.

They may also be useful in treating patients with penetrating abdominal trauma; a rapid heart rate caused by paroxysmal supraventricular tachycardia (PSVT); hypotension due to hypothermia; septic shock; urologic shock which cannot be controlled by other means; uncontrolled gynecological hemorrhage; and ruptured ectopic pregnancy.

I’m sure at least a couple of items on the list are curious to some readers. Let me explain what actually happens in the body when the suit is applied.

Once applied, the PASG increases peripheral vascular resistance. This limits blood return from the areas covered by the suit, which created pressure limiting the potential for blood getting into the bleeding area. It increases cardiac output. The pressure created peripherally increases pre-load to the heart, therefore increasing output.

Some of us were taught that PASG suits would auto transfuse up to two liters of blood. Auto transfusing does occur to a limited degree.

The PASGs increase central perfusion pressure. When it comes to head injuries, that point interests me. We are taught that use of PASGs on patients with head injuries might be a contraindication, but studies on comatose patients actually show that increasing blood pressure to the brain overcame intracranial pressure increases.

Moving on, let’s look at PSVT and why people with persistent tachycardia benefit from PASG.

Patients with symptomatic PSVT have decreased cardiac output due to the heart rate. If you are on a basic unit, without medications for this, or if the drugs don’t work, PASG increases cardiac output and some studies have shown that to be beneficial.

With conditions like anaphylaxis, septic and urologic shock, these patients have dilated vascular beds. Think of this as a pressurized system that suddenly gets bigger.

Relating it to fire fighting terms, think of it like you’re pumping water into 1.5-inch lines off a water thief appliance and someone opens a 2.5-inch line.

It’s the same thing with dilated vascular beds – the systems get bigger and the pressure drops. The PASG helps reverse that condition by compressing half the body, helping to compress the expanded circulatory system.

Of the items listed on the physicians’ association list, the two I was most excited to see were ectopic pregnancies and uncontrolled gynecological hemorrhage. If you have ever been on one of these calls, you know the patients can exsanguinate (bleed out) right before your eyes and there’s not much that can be done about it in the field. Studies show the PASG can help and give some hope in those situations.

The other item on the list I was pleased to see was the AAA studies. Patients with ruptured abdominal aortic aneurisms can also crash very quickly and anything that can be done to slow the bleeding until they get to surgery is a big plus. I personally had a case where we used a PASG on a rupture case and the patient stayed in the suit until surgery, which successfully repaired the damage and the man returned to a productive life.

It also should be pointed out that PASGs may not be appropriate for the following: penetrating chest trauma, diaphragmatic rupture, cardiogenic shock, cardiac tamponade, cardiac arrest, bleeding above the diaphragm, and as a splint to the lower extremities.

In these cases just remember what the suit does and what it cannot do. Don’t use it without considering its function and think about not only what good it will do, but what harm it can do to the patient. For example, in the case where the patient has blood or fluid in the chest, the suit is going to keep more blood in the upper part of the body and may cause the patient to bleed more. Considering the circulatory effects the suit has, you don’t want it to use it for a splint, nor do you want to use it for cardiac arrest patients as it just doesn’t seem to help them.

Topics For Future

While I may have started out with a whole list of ideas I wanted to talk about regarding bleeding control, I’ve only covered a few of them. In future columns, I’ll discuss more equipment and the science that tells us how to use them and why they work.

In the meantime, feel better about keeping that tourniquet in your bag and, when needed, use it in accordance with your protocols. While you’re at it, go look for that PASG, check it out, familiarize yourself with its applications and don’t be afraid to use it when appropriate.

Till next time, be safe.

Editor’s Note: Will Chapleau, who has 30 years of EMS experience, is chief of the Chicago Heights (Ill.) Fire Department. He has served as the chairperson for the Prehospital Trauma Life Support (PHTLS) program since 1996 and has been a member of its international faculty since 1984. He is a board member of the National Association of EMS Educators.

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