MAST

[nypamedic43]

I received this article in an email from another site I belong to. I thought I would pass it along.

The EMS Contrarian

by Bryan E. Bledsoe

MAST Again: Medical, Not Military Anti-Shock Trousers

Read Bledsoe's March Column: The MAST Will Not Die

This will be my last tirade on MAST. In my last monthly column, I had a fairly detailed overview on the MAST. Like many things in EMS, discussions of MAST bring out an emotional response from many of us who used the device in the 1970s and 1980s. And for this reason, the issue is worth revisiting.

MAST discussions tend to bring the usual comments about the “Houston study” being flawed and a constant reminder of how many lives MAST saved in Vietnam. Everybody knows that MAST saved many a life in Vietnam, right? Guess what? MAST were not used in Vietnam (except for a small field study). Here, too, is another EMS urban legend that must give up the ghost.

MAST were designed by the National Aeronautics and Space Administration (NASA) in the 1970s. They were part of a congressional mandate to assure that civilians derive something of value from the billions of dollars spent annually on the space program. MAST were a derivative of the G-suit worn by fighter pilots. At NASA, they were primarily used for physiological tests on astronauts as they prepared for their trips to space. A press release from NASA stated, “The anti-shock trousers are an adaptation of the anti-gravity flight suits originally developed for pilots and astronauts. They were modified to combat internal bleeding in trauma victims in emergency situations.”1

As I answered several queries to last month’s article, I went back to all of the original research on MAST. I could find no evidence that MAST were used in Vietnam with the exception of a small field study. That study, conducted in 1969, did not involve MAST per se, but involved actual “G-suits” used by pilots of high-performance aircraft. The study had a cohort of eight patients (four Americans and four Vietnamese) ranging in age from 18-24 years. Of the eight patients, seven survived evacuation, but only four eventually survived.2

I looked and looked and even requested several books via interlibrary loan. I could not find one picture or one mention of MAST in Vietnam. Finally, I decided to call an expert. In fact, I called THE expert: Colonel Warner D. “Rocky” Farr. Rocky is a friend and the Command Surgeon for the United States Special Operations Command (USSOCOM). I co-chair the Certification and Evaluation Board (CEB) for all Special Forces medics through USSOCOM (thus, how I got through to the colonel). In addition, Rocky is a military historian and was a medic in Vietnam before he attended medical school.

He stated, “I never saw MAST pants in the People’s Republic of Vietnam. They came in during the late 1970s as a part of ATLS (Advanced Trauma Life Support). There was one study in JAMA and they were used occasionally in the post-Grenada invasion.”3 For those of you too young to remember, the Vietnam War ended April 30, 1975 (before MAST were made).

There. That’s it. Breathe in, breathe out, move on. MAST were NEVER Military Anti-Shock Trousers -- they were Medical Anti-Shock Trousers. They were developed by NASA and first manufactured by the now-defunct EMS manufacturer Dyna-Med. They had some sporadic use in the military — but not during wartime.

It is amazing to me how these stories develop and spread. We know why R. Adams Cowley made up the “Golden Hour.” He had to sell his multi-million dollar shock trauma center (and assorted helicopters) to the Maryland legislature and the people of that great state. Because Cowley was so well-respected, the concept was bought “lock, stock and barrel.” Even now that we know the “Golden Hour” is a myth, people are still reluctant to give it up. In the most recent edition of our five-volume paramedic textbook series, borrowing from PHTLS, we now use the term “Golden Period.”4 That is about as nebulous as you can get. Why people had to embellish the life and times of MAST in Vietnam is and will forever be a mystery. I guess it made for good night time station stories.

I promise I will leave MAST in the old cabinet in the back of the station where they have been for the last 15 years. But this has been an interesting study of how we EMS people embrace and refuse to give up something as boneheaded as the Medical Anti-Shock Trouser. When I get time, I will detail how I saw a chicken come back to life with only the music from an accordion as intervention. Maybe I need a debriefing…

--------------------------------------------------------------------------------

1Available at: http://www.sti.nasa.gov/tto/spinoff1996/28.html (Accessed April 14, 2008).

2Cutler BS, Daggett WM. Application of the “G-Suit” to the control of hemorrhage in massive trauma. Annals of Surgery. 1971;173:511-514.

3Personal communication. Colonel Warner B. “Rocky” Farr (April 14, 2008).

4Bledsoe BE, Porter RS, Cherry RA. Paramedic Care: Principles and Practices, Third Edition. Upper Saddle River, NJ: Brady/Pearson Education, 2009.

[Dustdevil]

The fact that he has to keep responding to this issue is just a really, really sad reflection of the state of our profession.

[mobey]

The fact that he has to keep responding to this issue is just a really, really sad reflection of the state of our profession.

Hey man, I don't care what they say, I have seen them save lives!!

*End quote from every 40 yr old EMT in Canada"

[Timmy]

MAST are those anti shock things yeah? Cant say I've ever seen them...

[JPINFV]

Hey man, I don't care what they say, I have seen them save lives!!

*End quote from every 40 yr old EMT in Canada"

They've saved as many lives as Chuck Norris' tears.

[tniuqs]

I have always wondered why MAST just about disappeared as I too have had the distinct pleasure of observing that they do work ... granted anicdotally, but then again maybe I'm just old fashioned or can't take accurate BPs ??? Hey sometimes the OLD ways are the best ways then again maybe not.

I don't agree with Bledsoe that this an issue of emotion at all, moreover the curiousity of the human to shunt blood to core organs in shock, an alpha adrenergic response this just made sence to me, hey how about Levo ..... (ps I heard that whats is in Chuckies tears)

ARNIE ROCKS PERIOD !<edited after JPINFV boast> :twisted:

I think my confusion is partly is because the "G" suit continues to be in exsitance and continues improved to allow the human body to withstand up to 7 "G"'s, did human physiology suddenly change or are we more concerned in keeping pilots alive than the general population ? hmmm. :roll:

Dr. B. Bledsoe: This will be my last tirade on MAST. In my last monthly column, I had a fairly detailed overview on the MAST. Like many things in EMS, discussions of MAST bring out an emotional response from many of us who used the device in the 1970s and 1980s. And for this reason, the issue is worth revisiting. MAST discussions tend to bring the usual comments about the “Houston study” being flawed

I believe that with the abismal survival rates with the trauma patient we should revisit many other "ideas" as well but, primarily focusing on decreasing blood loss.

1- teach more hemostat application (s)

2- increase use of tourniquets, (obliterate the old myth that continuallys to being promoted as "last ditch attempts" by FA schools that have not looked at there curiculums for more than 30 years)

3- pack off penetrating injuries.

4- stop making kool-aid, get some volume expanders on the trucks: GO hypertonic and spans GO!

5- or cooking mashed potatoes .... wonder who will pick that one up ?

OR ....

Maybe just ask all trauma patients to grunt instead for that "golden hour" and they will ALL be good to go.

cheers

ps trandelenburg is a ems myth as well.

[AZCEP]

I think my confusion is partly is because the "G" suit continues to be in exsitance and continues improved to allow the human body to withstand up to 7 "G"'s, did human physiology suddenly change or are we more concerned in keeping pilots alive than the general population ?

This is part of the problem in how the PASG was implemented. It was borrowed technology from a device that keeps healthy, normovolemic individuals from blacking/redding out. The G suit was never intended to increase blood pressure or perfusion of vital organs.

The PASG is a tool, like many others we have available. If more people would understand when to properly use them we would not continue to run into these issues.

[aussiephil]

Fortunately our service has withdrawn them from use.

I never used a PASG in anger, but some of the guys I work with have & are adamant they save lives. They transported on to hospital & the patient died when they removed them.

Does this not tell us something?????????

Maybe the pt was suffering multi organ failure & would have died anyway & all we did was prolong their death???

Goodbye MAST, don't come back.

[tniuqs]

Fortunately our service has withdrawn them from use.

I never used a PASG in anger, but some of the guys I work with have & are adamant they save lives. They transported on to hospital & the patient died when they removed them.

Does this not tell us something?????????

Maybe the pt was suffering multi organ failure & would have died anyway & all we did was prolong their death???

Goodbye MAST, don't come back.

but then again maybe I'm just old fashioned or can't take accurate BPs ???

Phil: I think you missed this part, I may be OLD but I can still take a accurate BP ... some of those OLD BOYS arn't as drunk as you initially thought.

Will take you to task on this one my upside down fiend .... YES, this does tell us something like who took them off incorrectly ? ... let me guess a cut happy surgeon NO tell me it aint true ? Could this be the Surgical approach over the Medical ... hey mate, can't tell you how many times I watched (in ICU) bellys get freaking shiney .... and "no cut" I was told let it tamponade their "too big a risk for surgery" ... FM gently ....a couple even made it out of the unit btw.

AZCEP: This is part of the problem in how the PASG was implemented. It was borrowed technology from a device that keeps healthy, normovolemic individuals from blacking/redding out. The G suit was never intended to increase blood pressure or perfusion of vital organs.

The PASG is a tool, like many others we have available. If more people would understand when to properly use them we would not continue to run into these issues.

What's that is this the explanation ? Tell me again that suddenly changing from 200 lbs to 1500 lbs because your feet are full of blood is Normotension ? Does the mechanism of action define "Hypovolemic Shock" ... not where I come from it don't ... take for example Iatrogenic Dynamic Hyperventilation ..... this also is a relative Hypovolemia is it NOT impedance of blood flow to the left side of the heart through a low compliace system.... hmm?

So just when "do you" suggest implimenting this garment then, Let's jusr remember that the first parachutes were not so successful either, funny its now a sport. Thing is that maybe the we were using them too late... doing the 30, 50, or the crackle of velcro indicator, thing was the problem OR maybe ??? The bleeding as I refered to prior was not controlled and we were causing multisystem failure ?

Hey what about the OTHER options I suggested ? Is it getting too hot in AZ or OZ land to open the door or think ?

Phil/ Timmy: Don't you use still use the big "T" with snake bites, I would have no idea because all the snakes here wear suits when the go to the Legislature or Parliment.

cheers :twisted:

ps ummm ... pirates rock

[AZCEP]

Must be heavy into the Labatt's tonight eh? :roll:

Normal blood volume does not equate to normal arterial blood pressure. I'm not sure where you misread that.

My suggestion is to use the device for lower extremity fractures including pelvic/hip fracture/dislocations. Don't use it to solve a volume/bleeding issue. Use it as a splinting device. You don't have to use anywhere near as much air pressure to accomplish it.