Factors in Low Morbidity and Mortality

The excellence of care of the wounded in Vietnam was the result of a combination of factors: rapid evacuation of the casualty, ready availability of whole blood, well-established forward hospitals, advanced surgical techniques, and improved medical management.

From the standpoint of methods used to wound- mines, high-velocity missiles, and boobytraps- as well as the locale in which many were, injured- in paddy fields or along waterways where human and animal excreta were common-- Vietnam was quite a "dirty" war. Yet helicopters were able to evacuate most casualties to medical facilities before a serious wound could become worse, There were, practically no conditions under which the injured was denied timely evacuation; weather, terrain, time of day, enemy contact, all were surmounted by the, capabilities of the air ambulances and the skill of their crews.

The use of whole blood, occasionally even before the arrival of an air ambulance, contributed to the low mortality rate in Vietnam by better preparing the wounded for evacuation. Blood packaged in styrofoam containers which permitted storage for 48 to 72 hours, in the field could be placed in the forward area in anticipation of casualties. This was a marked increase in the utilization of whole blood, since virtually none was used at the division level in World War II. Stocks of blood, drawn from PACOM (Pacific Command) in the early years and later

*This chapter, involved with statistical analysis of World War II, Korea, and Vietnam as indices of the quality of care of the wounded, is subject to all the handicaps of comparison. Reporting procedures have changed over the last 25 years, and the most recent reports included more individuals through the increased scope and efficiency of the data collecting system; moreover, some information, gathered for Vietnam had no true counterpart in the previous conflicts. Yet another problem is semantics: "hospitals" is different from "all medical treatment facilities," which presents the danger of "comparing" what is actually two different populations. Concern with these problems is highly justified, and any reader must view comparisons merely as illustration of trends, not as absolute, fact. While the figures will change as more complete information becomes available, the basic fact which they illuminate will not- the care of the wounded in Vietnam has been superior to that given in combat anywhere at anytime.

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Largely from CONUS (continental United States), were always sufficient.

The relative stability of forward hospitals in Vietnam made possible the use of sophisticated equipment. Air conditioning to counter the extreme heat, dust, and, humidity allowed better control of the environment of the wounded before, during, and after surgery, and was necessary for the proper functioning of the highly sensitive equipment. Commenting on hospital apparatus, the USARV neurosurgical consultant, Lieutenant Colonel Robert C. Leaver, MC, stated, "The traditional equipment seen in neurosurgical centers throughout the United States is available, i.e., respirators, Stryker frames, and hypothermia units. Other than the physical deficiencies of a hospital in a combat area, there is little that would distinguish our neurosurgical wards from those in hospitals in America."

Surgical technique as practiced in Vietnam was certainly as advanced as the state of the art in general, and perhaps more so in the realm of trauma. Contrary to traditional procedure, surgeons in Vietnam rediscovered that wounds (except cranial and facial, and some hand injuries) responded better to a delayed closure which permitted necessary drainage. Management of severe liver injury was a real therapeutic challenge since massive transfusion, control of relatively inaccessible bleeding, and removal of large portions of liver substance were often required. Surgeons performed complex operations daily and routinely in all hospitals, not just selected ones in the rear. Vascular surgery, sporadic in Korea, was commonplace in Vietnam, and surgeons became so adept that not only thoracic but also general and orthopedic surgeons routinely performed repairs.

The high level of skill was maintained despite the turnover of medical officers. Since surgeons arriving in Vietnam were not adequately prepared by their background in civil trauma to treat combat casualties, they were attached to experienced teams for orientation and learned technique in the operating room.

Improved medical management of the casualty contributed to the quality care. Surgery itself had become a part of the continuing process of resuscitation and a weapon in the struggle against shock. The team approach, in which surgeons of a variety of specialties operated together, also proved highly effective; a "team" for head injuries, for example, included a, neurosurgeon, ophthalmologist, oral surgeon, otolaryngologist, and plastic surgeon. If the casualty had multiple injuries, more than one surgical team operated simultaneously.

Survival Statistics

Between January 1965 and December. 1970, 133,447 wounded were admitted to medical treatment facilities in Vietnam; 97,659 of these were admitted to hospitals. The hospital mortality rate for this period was 2.6

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percent, compared to 4.5 percent in World War II and 2.5 percent in Korea. The very slight increase in hospital mortality in Vietnam over that in Korea was a result of rapid helicopter evacuation which brought into the hospital mortally wounded patients who, with earlier, slower means of evacuation, would have died en route and would have been recorded as KIA (killed in action). Assuming that most of those patients who died within the first 24 hours in hospitals belong in this class, the rate would be much closer to 1 percent. Actually, it is further testimony to the high quality of medical care provided in Vietnam where, even though mortally wounded casualties arrived at Army hospitals, the mortality rate was only marginally greater than in Korea.

Perhaps a better index of the effectiveness of medical treatment was the ratio of deaths to deaths plus surviving wounded (or "deaths as a percent of hits"). For World War II, it was 29.3 percent; Korea, 26.3 percent; and Vietnam, 19.01 percent. The ratio of KIA to WIA (wounded in action) was as follows: World War II, 1:3.1; Korea, 1:4.1; Vietnam, l:5.6.

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Patient Care Indices

Since the task of the combat physician is to salvage as, much limb or function as possible, and the goal of the Medical Department is the salvage, of lives, it is proper that the accomplishments of the Medical Department mission in Vietnam be measured in terms of lives recovered rather than numbers lost.

The bed occupancy rate in Vietnam ran approximately 60 percent, and that in offshore facilities about 50 percent, which allowed ample flexibility to respond to fluctuating casualty rates and remain capable of providing optimum medical care.

The average length of stay per case for patients in Vietnam was considerably below that of both earlier conflicts:

This reduction of approximately 20 percent reflected the advances in wound management and patient care.

Of the, 194,716 wounded in Vietnam, (January 1965-December 1970), 61,269 (31 percent) were, treated and returned to duty immediately. Of those admitted to treatment facilities, the distribution was as follows:

42.1 percent returned to duty in RVN
7.6 percent returned to duty in PACOM
33.4 percent returned to duty in CONUS
2.7 percent, still hospitalized, 31 December 1970
14.2 percent other dispositions (died; transferred to Veteran's Administration hospital; discharged; and so forth)

Two to three percent, of the hospitalized wounded in Vietnam had significant vascular injuries, and the amputation rate for those with major arterial injury was about 13 percent. This rate was approximately the same as that for Korea, and markedly less than the 49 percent rate for World War II. The, approach was for maximum conservation of stump length which, in conjunction with developments in prosthetic manufacture, decreased morbidity and length of hospitalization among orthopedic patients.

The lethality of modern, weapons directly affected the work of the medical personnel who attempted to undo the damage. While one must

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be wary of dubbing things "new," certainly the problems which medical personnel in Vietnam encountered were, more, complicated than before.

Mechanics of Wounding

High-velocity, lightweight rounds from M16/AK47-type weapons have greater kinetic energy, and leave larger temporary and permanent cavities and more severe tissue damage than do low-velocity projectiles, and their easy deflection by foliage resulted in tumbling and spinning and the generation of even larger entrance wounds. Moreover, blood vessels not in the direct path of the missile were affected. The bullet usually disintegrated and was rarely found whole even when all exit wound was absent. These rapid fire weapons increased the chances of multiple wounding, which complicated resuscitation and treatment.

The claymore mine received its first field trials by both sides in Vietnam. The intensity of peppering and velocity of the fragments often resulted in deep penetration in a number of sites. The extensive use of mines and boobytraps in Vietnam created a serious medical problem: the proximity of the blast caused severe local destruction, and tremendous amounts of dirt, debris, and secondary missiles were hurled into the wound. Massive contamination challenged the surgeon to choose between radical, excision of potentially salvageable tissue and a more conservative approach which might leave a source of infection,

Causative Agents

The data on the physical agents which caused wounds and deaths reflect the nature of the combat. Much higher proportions of the casualties were caused by small arms fire, and by boobytraps and mines, than in Korea or World War II, and much lower percentages were caused by artillery and other explosive projectile fragments. This relationship generally was more pronounced among the fatalities than among the wounded. (Table 6)

Statistics compiled at different times in the Vietnam conflict mirrored the shift in combat from the defensive to the offensive. In 1965, U.S. forces were most concerned with establishing and defending their bases, and only in 1966 did they launch operations to check the enemy offensive. By 1968, troops were usually engaging the enemy in his defensive positions. Wounding from small arms fire decreased from 42.7 percent in June 1966 to 16 percent in June 1970, while the percentage from fragments (including mines and boobytraps) rose from 49.6 percent in 1966 to 80 percent in 1970.

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 ¹ January 1965-June 1970.
Source: Statistical Data on Army Troops Wounded in Vietnam, January 1965-June 1970, Medical Statistics Agency, Office of the Surgeon General, US Army.

Anatomical Location of Wounds

The rapid fire weapons of the enemy resulted in a significant increase over World War II and Korea in the percentages of multiple wounds among the distribution of wounds by site. (Table 7)

Small arms fire caused approximately two-thirds of the wounds of the head and neck, and three-fourths of the trunk wounds; fragments accounted for the remainder. Fragments and small arms contributed fairly equally to wounds of the extremities.

The distribution of fatal wounds by location differed from that for total wounds since some areas were much more likely to involve mortal

¹ For a 24-month period.
² Including multiple wounds.
Source: Statistical Data on Army Troops Wounded in Vietnam, January 1965-June 1970, Medical Statistics Agency, Office of the Surgeon General, US Army.

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injuries than others thus the 14 percent of the wounds located in the head and neck region accounted for 39 percent of the fatalities. This was followed by 19.3 percent fatal wounds in the thorax; 17.9 percent, abdomen; 16.1 percent, multiple sites; 6.8 percent, lower extremities; and 0.9 percent, upper extremities. Twenty to thirty percent of the penetrating head wounds brought in from the field in Vietnam were classed as "expectant" cases, and little could have been done for them; however, the mortality rate for the others was rather low because of early evacuation, extensive use of blood, and the presence of fully trained neurosurgeons in the combat zone. Most of the abdominal fatalities were from extensive liver destruction or multiple organ involvement.

Certainly the data on relative lethality of wounds and the distribution by causative agent showed the advantage of wearing properly designed body armor. Had helmets been worn, they would have proved very effective against fragments, although little could be done in the event of a direct hit by a small arms round. To quote Lieutenant Colonel, (later Colonel) William M. Hammon, MC: "If our combat troops . . . were to wear the helmet, we, believe that about 1/3 fewer significant combat casualties would need to be admitted to a neurosurgical center here in Vietnam." Flak vests did prove effective against three-fourths of the fragments which struck the thorax, thereby increasing the percentage of gunshot wounds to other areas of the body to 75 percent of chest wounds.

Troops, in static positions, or in air or ground vehicles, usually wore both helmets and flak vests, but soldiers on the move found the body armor too heavy and too hot. Some commanders (and some individuals regardless of the command decision) decided to forego the protection rather than accept the reduction in mission capability and the increase in heat casualties.

The continuous thrust of the U.S. Army Medical Department in combat surgery is on the development of better procedures and ancillary techniques for the care of the wounded. In Vietnam, concern centered on the areas of anesthesia, blood and plasma expanders, treatment of burns, wound healing, shock, and surgical routine.

Anesthesia

Most surgery in Vietnam hospitals was done under a general anesthetic, usually thiopental induction and maintenance with halothane, nitrous oxide, and oxygen. Most anesthesiologists favored halothane, with its rapid action, ease of administration, nonflammability and applicability

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to all cases; also, it did not produce nausea and did not mask critical drops in blood volume.

Local anesthetics were used only for very minor wounds and a, few delayed primary closures, Employment of spinal anesthesia was very limited. The emphasis continued on, development of safe, simplified methods of portable inhalation anesthesia.

New concepts for assisting the breathing of the critically injured were also developed to meet Vietnam requirements. Prolonged mechanical support was necessary in some cases to minimize oxygen deficiency, and while respirators were ordinarily used, the possibility existed that harmful bacteria might be introduced since proper sterilization was not always feasible under combat conditions. New respiratory assistance devices, eliminating or reducing that potentiality, were tested.

Blood and Plasma Expanders

Frequently transfusions of whole blood were initiated long before the casualty reached a facility with the capacity for cross-matching blood, and in these cases, type O low titer blood was used. As a rule, any, patient who had received four or more units of type O low titer was continued on this type, while those with less than four were matched at the hospital.

Massive transfusions (one surviving patient had received 92 units), although lifesaving, presented problems of their own. A tendency toward bleeding appeared after multiple transfusions, but it was found that fresh frozen plasma or, if possible, freshly drawn blood could control the condition. Also, the patient whose body temperature dropped as a result of extensive transfusion became a serious problem. Two evacuation hospitals, utilized microwave ovens to warm, the whole unit of blood, in seconds to counter this condition.

Burns

The most unfortunate, aspect of the burn injuries incurred in Vietnam was that more than half were accidental and therefore preventable. Burns associated with enemy fire, while fewer in number, accounted for almost, 70 percent of the fatalities because of their severity and associated wounds. A factor in the high mortality was that most combat bums occurred in an enclosed space, such as an armored personnel carrier or a bunker, and were, therefore, complicated by inhalation injuries.

Burn cases were stabilized in-country and then evacuated to the 106th General Hospital in Japan, where, a special burn unit had been established. Of the burns treated by the 106th, 27 percent returned to duty, 66 percent were evacuated to the burn unit at Brooke Army Medical Center, Fort Sam Houston, Tex., and 7 percent died.

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Sulfamylon ointment was employed to prevent infection. If evacuation to Japan was delayed more than 48 hours, treatment was initiated in Vietnam. Since the standard treatment of phosphorus burns with copper sulfate solution was found to be toxic in itself, their management became even more difficult and debridement of the wound grew more important.

Wound Healing

The Surgical Research Team, WRAIR (Walter Reed Army Institute of Research), tested in Vietnam several experimental items, developed to aid wound healing. An antibiotic preparation, packaged as an aerosol, was distributed to aidmen in various tactical units. Immediate use on an open wound acted to retard bacteria growth, and resulted in decreased morbidity, Tissue adhesives which had low toxicity, degraded relatively rapidly, and spread well proved valuable in surgery on the lung, kidneys, and liver. The Surgical Research Team utilized them with excellent results as early as 1968.

Shock

Shock was a killer which was checked somewhat by the rapid evacuation, system and the whole blood available to the wounded in Vietnam. Yet even so, mortality rates were increased by a postoperative pulmonary complication known as shock lung or wet lung where the lung or thorax had been traumatized. By the time the condition could be detected by X-ray, it was usually too advanced to respond to treatment. However, after extensive investigation, Colonel James P. Geiger, MC, surgical consultant from, June 1969 to June 1970, identified the mechanics of the problem and demonstrated that the complication could be forestalled by the use of diuretics in those likely to be so afflicted. This treatment significantly reduced the morbidity and mortality in the syndrome.

Surgical Routine

An outstanding feature of medical service in Vietnam was the quality and extent of care given in the battle area. Any type of medical or surgical specialist was available in the combat zone. For example, by the spring of 1968, there were 10 neurosurgeons at five Army hospitals, supervised by a board-certified neurosurgeon.

Sophisticated operations were handled as a matter of routine. Laparotomies were done "on suspicion" (which proved positive in about 25 percent of the cases) in a zone where heretofore there was a degree of reluctance to operate even when abdominal penetration was certain. Primary repairs were performed on veins which had simply been ligated in earlier conflicts, and fasciotomy, cutting the tissue sheathing the

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muscles and reducing pressure on the muscles, was not uncommon. In a few instances, limb salvage was possible by constructing an extra anatomic bypass, tunneling a graft through a new route around the area, until the wound healed and a permanent vascular graft could be inserted. The expert surgeon, supported by a skilled medical team and well-equipped facilities, provided a quality of care superior to that in any previous conflict.