The Mobile Army Surgical Hospital: Vietnam War – MUST vs. MASH

The Vietnam War was radically different from either the Korean War or World War II. Guerilla tactics employed by the Viet-cong required drastic changes in combat philosophy, with resulting changes in combat medical support. During this conflict, the “battlefront” was not readily evident. Therefore, some military planners did not regard mobile hospitals as essential. Thus, some U.S. military hospitals in Vietnam were established as semi-permanent, fully equipped facilities.

The Medical Unit Self-Contained Transportable (MUST) units were introduced in Vietnam. These were expandable, mobile shelters with inflatable ward sections. Expandable sections were also provided for the radiology, laboratory, pharmacy, dental and kitchen areas. Most notable among the MUST units was the 45th Surgical Hospital in Tay Ninh, Vietnam. In November 1966, following construction of a semipermanent facility, mortars struck the hospital. The hospital commander, Major Gary P. Wratten, was killed. The hospital then set up a new position in northeast Tay Ninh. It was subsequently again struck by mortar, without sustaining serious casualties. The 45th Surgical Hospital performed exceptionally well despite these incidents, and the MUST equipment was provided to several more surgical hospitals that deployed to Vietnam. MUST units remained semipermanent, relatively stationary facilities during the early years of the war. However, in 1968, the US. Pacific command surgeon ordered that all MUST units become mobile. Thus, the MUST units then assumed the role traditionally relegated to the MASH. For the remainder of the war, MUST units were ordered to maintain their equipment and training to ensure mobility.  Cialis Jelly

One of the few MASH units deployed to Vietnam was the 2nd MASH. The 2nd MASH was active in south Vietnam from October 1966 to July 1967. During this nine month period, 1,011 surgical cases were performed at this 60-bed unit. The experience of the 2nd MASH has been extensively chronicled. At the 2nd MASH, the management of high-velocity wounds, vascular trauma, colorectal injuries and burn injuries were vastly different from that of the Korean War era, reflecting innovations in the delivery of surgical care that had occurred during the preceding decade. Additionally, improvements in aeromedical evacuation contributed significantly to a decrease in mortality.

In Vietnam, surgeons in the MUST and MASH units contributed to several major innovations in combat casualty management, particularly in wound and burn care. Early debridement of high-velocity missile wounds and delayed primary closure were universally practiced among military surgeons in Vietnam. Further improvements in vascular surgery during the Vietnam War resulted in an average amputation rate of 8%. Once again, this reduction in amputations was due to improvements in surgical technique but more directly related to an average evacuation time of two hours. Exploratory laparotomies were performed more frequently, particularly in cases of blunt trauma or blast injuries, where internal abdominal injuries were less obvious. viagra jelly

There were novel improvements in the care of the burned patient. Military surgeons developed sulfamyalon and came to realize that fluid resuscitation was vitally important in the treatment of burns. This resulted in a 50% reduction in mortality for burn patients in the Vietnam War, compared to the Korean War. The importance of aggressive debridement of phosphorous burns was also emphasized, improving survival of patients exposed to this agent.

Equally important were improvements in anesthesia and critical care. Surgeons in the Vietnam conflict began to realize the importance of perioperative fluid resuscitation. Blood, plasma, low molecular weight dextran and crystalloid were all used for resuscitation. The benefit of resuscitation with balanced salt solutions as well as whole blood was demonstrated by studies conducted at the Naval Support Activity in Da Nang. These studies clearly showed that balanced salt solutions replete the extracellular compartment and are therefore an essential component to the resuscitation of patients in hemorrhagic shock. Plastic bags replaced glass bottles and became a more efficient means of transporting blood and crystalloid. Central venous catheters were placed in some casualties to guide fluid therapy. Central venous pressure was measured by a standard manometer, and arterial catheters were often placed to obtain serial arterial blood gases. Anesthesiologists began using halothane, which had fewer negative inotropic effects. Newer techniques in the management of ventilated patients led to earlier extubation in the rear hospitals.

“Da Nang Lung” or acute respiratory distress syndrome (ARDS) was seen in casualties with severe hemodynamic compromise who often required massive blood transfusions. ARDS was not seen in earlier conflicts, since soldiers who were severely compromised often did not survive transport to even forwardly mobile medical units. Surgeons initially used diuretics and fluid restriction to treat ARDS with little success. Clinical suspicion became the best diagnostic tool as ARDS is often advanced once detected on chest radiograph. The hypoxia seen in these patients was refractory to standard oxygen therapy. The work of Colonel Robert Hardaway and Dr. David G. Ashbaugh showed the value of continuous positive airway pressure in the maintenance of adequate arterial oxygenation in patients with ARDS. Viagra Super Active

The guerilla warfare in Vietnam led to additional improvements in aeromedical evacuation. Air ambulances were responsible for saving thousands of lives in the battlefield. The UH-1D (Huey) transported six-to-nine patients at one time. Most patients were evacuated within 30-35 minutes following injury, with few evacuations occurring after more than two hours. Flight medics were skilled and competent at transporting severely injured casualties. “Dust-off” was the call sign used to summon these courageous aviators. As a result of efficient and expeditious evacuation, overall hospital morality was 2.6% during the Vietnam War. Ironically, this was slightly higher than that seen during the Korean War (2.5%). This paradox can best be explained by the fact that improvements in aeromedical transport allowed evacuation of more very severely injured patients to nearby hospitals. Many of these patients would not have survived the longer evacuation time required during the Korean War.

During the early years of the Vietnam War, the Air Force used cargo planes to evacuate patients to hospitals in the rear. By 1968, casualty evacuation had increased to almost 6,000 patients per month. The Air Force then dedicated several C-118 airplanes for aeromedical evacuation. These aircraft were supplemented with special medical equipment and medical personnel.
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One of the hallmarks of the Vietnam War was the development of an organized military blood program. The distribution of blood was initially regulated at the 406th Medical Laboratory in Japan. Mobile teams were created to procure and distribute blood to hospitals in Vietnam. However, type-specific blood was distributed to hospitals in Japan, while universal donor O-negative blood was transported directly to Vietnam. Physicians recognized and treated coagulopathies resulting from massive hemorrhage and disseminated intravascular coagulation. Various strategies were adopted to treat coagulopathy, including the administration of fresh blood, fresh frozen plasma, cortisone, heparin and epsilon aminocaproic acid. Advancements—including the use of adenine to preserve cells, new methods of refrigeration and styrofoam blood containers—also occurred in the storage of blood. These advancements resulted in an average increase in shelf life of whole blood and blood products from 21-to-40 days.