Medical Anti-Shock Trousers

Advisory No. 97-04

Date Approved: August 7, 1997

New York State Department of Health Bureau of Emergency Medical Services

Note: This advisory guideline announces important changes in the Statewide Basic Life Support Adult and Pediatric Treatment Protocols. Revised copies of each of the protocols affected by these changes are attached. Revised copies of each of the protocols affected by these changes are also being sent to all emergency medical services agencies statewide. Regional Emergency Medical Advisory Committees, and regional, system, and service medical directors are directed to facilitate use of the revised protocols at the local level, and are further advised to modify local protocols, policies, and procedures accordingly.

Current Statewide Basic Life Support Adult and Pediatric Treatment Protocols stipulate that Medical Anti-Shock Trousers (MAST), also known as the Pneumatic Anti-Shock Garment (PASG), should be inflated if the systolic blood pressure is below 90 mm Hg in adults or below 70 mm Hg in children and signs of inadequate perfusion are present, if MAST (PASG) are available. The State Emergency Medical Advisory Committee has reviewed these protocols, and concludes, on the basis of recent scientific evidence, that prehospital MAST (PASG) use in New York State should be considered only in adult major blunt trauma with severe hypotension (systolic blood pressure < 50 mm Hg) and hypotension (systolic blood pressure < 90 mm Hg) associated with unstable pelvic fracture.

In 1989, Mattox et al, in a prospective randomized study of 911 adult trauma patients, mostly with penetrating injuries, found that MAST (PASG) use was associated with longer scene times, and worsened the survival of adult patients with systolic hypotension (BP < 90 mm Hg) as well as those with primary thoracic injuries who presented in traumatic cardiac arrest. In 1992, Cooper et al, in a retrospective study of the efficacy of MAST (PASG) use in 436 pediatric trauma patients, mostly with blunt injuries, from the National Pediatric Trauma Registry who presented in hypotensive shock, found similar results. In 1993, Cayten et al reported the results of a retrospective study of MAST (PASG) use in 629 hypotensive adult trauma patients which concurred with Mattox's findings, although they were able to demonstrate a small but statistically significant survival advantage in severe hypotension (BP < 50 mm Hg). While there have been no prospective studies and no published trauma registry data in support of MAST (PASG) use for hypotension associated with unstable pelvic fractures, retrospective reviews and cases reports consistently support MAST (PASG) use in such circumstances.

In 1997, O'Connor et al performed a collective review of the scientific literature as an evaluation of MAST (PASG) in various clinical settings. On the basis of this review, Domeier et al developed a position paper on use of MAST (PASG) for the National Association of EMS Physicians, the Summary Recommendations from which, as they pertain to trauma, are summarized below.

MAST (PASG) are "usually indicated, useful, and effective" (Class I evidence) for:

  • None.

MAST (PASG) are "acceptable, of uncertain efficacy, [although the] weight of evidence favors usefulness and efficacy" (Class IIa evidence) for:

  • "Hypotension due to suspected pelvic fracture;
  • Severe traumatic hypotension (palpable pulse, blood pressure not obtainable). *"

MAST (PASG) are "acceptable, of uncertain efficacy, may be helpful, probably not harmful" (Class IIb evidence) for:

  • "Penetrating abdominal injury;
  • Lower extremity hemorrhage (otherwise uncontrolled); *
  • Pelvic fracture without hypotension; *
  • Spinal shock. *"

MAST (PASG) are "inappropriate, not indicated, may be harmful" (Class III evidence) for:

  • "Adjunct to CPR;
  • Diaphragmatic rupture;
  • Penetrating thoracic injury;
  • Pulmonary edema;
  • To splint fractures of the lower extremities;
  • Extremity trauma;
  • Abdominal evisceration;
  • Acute myocardial infarction;
  • Cardiac tamponade;
  • Cardiogenic shock;
  • Gravid uterus."

* Data from controlled trials not available. Recommendation based on other evidence.

The literature cited supports the conclusion that the role of MAST (PASG) in the prehospital emergency medical care of adult and pediatric patients is extremely limited. The State Emergency Medical Advisory committee agrees with the National Association of EMS Physicians that the weight of the evidence favors the usefulness and efficacy of MAST (PASG) only for adult major blunt trauma with severe hypotension (systolic blood pressure < 50 mm Hg) and hypotension (systolic blood pressure < 90 mm Hg) associated with unstable pelvic fracture, a position which is consistent with the 1997 Edition of the Advanced Trauma Life Support Course of the American College of Surgeons.

The State Emergency Medical Advisory Committee (SEMAC) therefore recommends their use under these circumstances, although Regional Emergency Medical Advisory Committees (REMAC) may prescribe their use under other circumstances to address specific local conditions. The Statewide Basic Life Support Adult and Pediatric Treatment Protocols are being modified to reflect this change, and Regional Emergency Medical Advisory Committees, and regional, system, and service medical directors are advised to modify local protocols, policies, and procedures accordingly.

Selected References

  1. Mattox KL, Bickell W, Pepe PE, et al: Prospective MAST study in 911 patients. J Trauma 1989;29:1104-1112.
  2. Cooper A, Barlow B, DiScala C, et al: Efficacy of MAST use in children who present in hypotensive shock. J Trauma 1992;33:151.
  3. Cayten CG, Berendt BM, Byrne DW, et al: A study of pneumatic antishock garments in severely hypotensive trauma patients. J Trauma 1993;34:728-735.
  4. Flint L, Babikian G, Anders M, et al: Definitive control of hemorrhage from severe pelvic fracture. Ann Surg 1990;221:703-707.
  5. O'Connor RE, Domeier RM: Collective review: An evaluation of the pneumatic anti-shock garment (PASG) in various clinical settings. Prehosp Emerg Care 1997;1:36-44.
  6. Domeier RM, O'Connor RE, Delbridge TR, et al: Position paper: National Association of EMS Physicians: Use of the pneumatic anti-shock garment (PASG). Prehosp Emerg Care 1997;1:32-35.

Issued by:
Mark C. Henry, M.D.
Chairman, State Emergency Medical Advisory Committee

Authorized by:
Barbara A. DeBuono, M.D.
Commissioner, Department of Health