Ronald F. Bellamy

A profile of combat injury.

Traumatic combat injuries differ from those encountered in the civilian setting in terms of epidemiology, mechanism of wounding, pathophysiologic trajectory after injury, and outcome. Except for a few notable exceptions, data sources for combat injuries have historically been inadequate. Although the pathophysiologic process of dying is the same (i.e., dominated by exsanguination and central nervous system injury) in both the civilian and military arenas, combat trauma has unique considerations with regard to acute resuscitation, including (1) the high energy and high lethality of wounding agents; (2) multiple causes of wounding; (3) preponderance of penetrating injury; (4) persistence of threat in tactical settings; (5) austere, resource-constrained environment; and (5) delayed access to definitive care. Recognition of these differences can help bring focus to resuscitation research for combat settings and can serve to foster greater civilian-military collaboration in both basic and transitional research.

Epidemiology of trauma: Military experience

Battle injuries sustained in conventional warfare are more likely to be lethal than are injuries sustained by civilians. Depending on the tactical situation, mortality may range from 20% to more than 80% of all casualties. The American experience indicates that about 90% of the total mortality occurs on the battlefield. Such casualties, those classified as killed in action, die before reaching medical care. More than 90% of all battle injuries (morbidity) are caused by penetrating missiles. Exsanguination from wounds of the heart/great vessels and penetrating/perforating wounds of the skull cause the majority of battlefield deaths. The frequency distribution of injury severity appears to be bimodal. A large peak occurs at low injury severity and indicates a population of casualties with relatively benign soft tissue wounds. A smaller peak at high injury severity represents those killed in action.

Primary cysts and tumors of the mediastinum

A retrospective analysis was performed on 230 patients with primary cysts and tumors of the mediastinum seen at our institution from January 1944 to April 1989. We divided these patients into two groups. Group 1 was seen before 1970 and group 2 was seen from January 1970 to April 1989. There was a significant increase in the prevalence of malignancy in group 2 (47.2% versus 17.1%; p less than 0.0001) due to an increase in the number of lymphomas (22.6% versus 3.5%; p less than 0.001) and malignant neurogenic tumors (6.8% versus 1.1%; p = 0.0528). There was a significant increase in the number of malignant tumors in the anterior (59.5% versus 30.9%; p = 0.0022) and paravertebral (28.5% versus 2.8%; p = 0.0027) compartments in group 2. More patients with these tumors were symptomatic in group 2 (63.6% versus 5%; p = 0.0422). There was an increase of ancillary diagnostic studies performed to evaluate these tumors (76.0% versus 34.5%; p = 0.0422). Logistic regression analysis identified date of presentation (p less than 0.005), symptoms (p less than 0.01), size (p less than 0.005), and the anterior mediastinal compartment (p less than 0.005) as preoperative predictors of malignancy. The surgical approach to these tumors included more median sternotomy (30.1% versus 10.7%; p = 0.0008), anterior mediastinotomy, and cervical mediastinoscopy in group 2 (1.1% versus 17.5%; p = 0.0002). Long-term results support surgical resection in benign lesions and an aggressive multimodality approach to malignant lesions.

Small-volume infusion of 7.5% NaCl in 6% dextran 70® for the treatment of severe hemorrhagic shock in swine

In the initial treatment of the hypovolemic trauma patient, commonly used crystalloids have little clinical benefit in the small volumes generally infused during transport. We evaluated the efficacy of a small-volume infusion of 7.5% NaCl in 6% Dextran 70 as a treatment modality for an otherwise lethal hemorrhage in swine. Sixty chronically instrumented swine were randomized into one of four treatment groups: 0.9% NaCl (NS, n = 15), 7.5% NaCl (HS, n = 15), 6% Dextran 70 (DEX, n = 16), and 7.5% NaCl in 6% Dextran 70 (HSD, n = 14). Each animal was bled 46 mL/kg in 15 minutes. Five minutes after the completion of hemorrhage, the animals were infused with their respective treatment in a volume (11.5 mL/kg) equal to 25% of the shed blood. Of those animals receiving HSD, 100% survived until euthanized at 96 hours. In comparison, animals infused with NS, HS, and DEX had 96-hour survival values of 13%, 53%, and 69%, respectively. The survival rate of the HSD group was significantly better than that of the NS group (P less than .001) and the HS group (P less than .01). The infusion of HSD increased mean arterial pressure, PCO2, and plasma bicarbonate to a significantly greater extent than NS alone (P less than .05). These results demonstrate that a small-volume infusion of the hypertonic sodium chloride/dextran solution is superior to equal volumes of a standard crystalloid in resuscitating animals from hemorrhagic shock.

The wound profile: illustration of the missile-tissue interaction.

The wound profile was developed at the Letterman Army Institute of Research in order to measure the amount, type, and location of tissue disruption produced by a given projectile, and to present the data in a standardized, easy to understand picture. The entire missile path is captured in one or more 25 X 25 X 50 cm blocks of 10% ordnance gelatin at 4 degrees C. The penetration depth, projectile deformation and fragmentation pattern, yaw, and temporary cavity of the missile in living anesthetized swine muscle are reproduced by this gelatin. Measurements are taken from cut sections of the blocks after mapping of the fragmentation pattern with biplanar X-rays. These data are then reproduced on a life-sized wound profile which includes a scale to facilitate measurement of tissue disruption dimensions, a drawing of the loaded cartridge case before firing, the bullet weight and morphology before and after firing (and calculated percent of fragmentation), and the striking velocity. This technique allows us to determine the wounding character of the projectile without the need for elaborate and expensive high-speed cine and X-ray equipment, or the need for shooting live animals. The method improves our understanding of the wounding process and should lay the groundwork to assure more rational and effective treatment.

Cervical Spine Immobilization of Penetrating Neck Wounds in a Hostile Environment

Current guidelines concerning trauma suggest that cervical spine immobilization be performed on all patients with penetrating wounds of the neck. This study was undertaken to examine the risks and benefits likely to be found when such care is provided in a hazardous environment, such as the battlefield, or the scene of a terrorist attack or domestic criminal action. Data for casualties from the Vietnam conflict were reviewed to determine the potential benefit of cervical spine immobilization on the battlefield. In this population, penetrating cervical cord injury was always fatal and usually immediately so. Only 1.4% of all casualties who were candidates for immobilization might have benefitted from the care. However, the risk of performing immobilization in a hazardous environment is substantial since about 10% of casualties are incurred while helping other casualties. Mandatory immobilization of all casualties with penetrating neck wounds sustained in an environment hazardous to first aid providers has an unfavorable risk/benefit ratio.

Current shock models and clinical correlations

No useful purpose is served by developing therapeutic interventions that are applicable only in nonexistent patient populations. The history of laboratory hemorrhagic shock research may be a case in point because although many interventions have been proposed on the basis of animal experimentation, few if any have found a place in the treatment of human beings. For a laboratory shock model to have clinical relevance, it must replicate important aspects of shock as seen in human beings during or following massive blood loss. The difficulty in developing an animal model that incorporates these human aspects--hypothermia, hypoxia, hypotension, acidosis, coagulopathy, etc--must not be underestimated. Four methodological factors to consider are animal species, anesthesia, tissue trauma, and nociceptive effects. The development of an animal shock model will require several compromises and the results, whether dealing with mechanisms or therapeutic outcomes, must be considered suspect until confirmatory data are obtained from human studies.

True emergency coronary artery bypass surgery

Abstract Previous reports of emergency coronary artery bypass grafting often included cues that were not true surgical emergencies, thereby creating inappropriately favorable results. To accurately investigate this important subgroup of patients, we analyzed our recent experience with truly emergent coronary artery bypass grafting. From January 1984 to January 1989, 117 patients underwent true emergency bypass grafting for acute refractory coronary artery ischemia. Clinical deterioration was associated with failure of percutaneous angioplasty in 37 patients and instability during diagnostic catheterization in 13 patients. Refractory ischemia developed in the remaining patients while on the ward or in the intensive care unit. All operations were performed within four hours of surgical consultation, most within one hour. Overall in-hospital operative mortality was 14.5% ( 17 / 117 ), and 76.5% of deaths ( 13 / 17 ) were due to cardiac-related causes. Major morbidity occurred in 35.9% ( 42 / 117 ). Univariate analysis isolated ejection fraction, extent of coronary artery disease, previous myocardial infarction, hypertension, need for inotropic support, use of an intraaortic balloon pump, and cardiopulmonary resuscitation as risk factors for operative mortality. Stepwise multivariate analysis confirmed that previous myocardial infarction, hypertension, cardiopulmonary resuscitation, and reoperation were independently significant risk factors. Age, sex, diabetes, left main disease, and peripheral vascular disease had no significant impact on the prognosis. The 4% operative mortality ( 2 / 50 ) for patients taken directly to the operating room from the catheterization suite was significantly lower than the 22.4% mortaiity ( 15 / 67 ) associated with emergerncies arising on the ward or intensive care unit ( p

Hypertonic sodium chloride solutions for the prehospital management of traumatic hemorrhagic shock: A possible improvement in the standard of care?

Acute hemorrhage is a major cause of death in both civilian and military trauma. The suboptimal effect of the volume of standard crystalloids that can be infused during transport has resulted in a need for a more efficacious fluid for the prehospital management of both civilian and military trauma. Markedly hypertonic sodium chloride solutions have been shown to improve transiently the hemodynamic consequences of shock in animal models. The use of small volumes of 7.5% NaCl in 6% dextran 70 has resulted in a solution superior to equal volumes of standard crystalloids in the ability to resuscitate animals from hemorrhagic shock. The hypertonic sodium chloride/dextran solution has the potential advantages of improving survival, producing a beneficial hemodynamic effect with smaller fluid volumes, reducing total fluid requirements during resuscitation, and being stored easily. This solution may prove valuable in the early resuscitation of the hypovolemic trauma patient and merits further clinical trials.

Use of Artificial Intelligence for the Preoperative Diagnosis of Pulmonary Lesions

The relatively new field of artificial intelligence has spawned a variety of techniques associated with computer-assisted diagnosis. These techniques have been applied to the diagnosis of pulmonary lesions, but previous reports have focused on medical rather than surgical populations and the results have been evaluated using only retrospective patient surveys. We used a Bayesian algorithm to develop a diagnostic computer model for prospectively evaluating patients undergoing thoracotomy for suspected pulmonary malignancy. Patients who had a preoperative diagnosis were not included. Preoperative clinical and radiographic parameters for 100 consecutive patients were prospectively entered into the diagnostic model, which then categorized the lesion as benign or malignant. The computer predictions agreed with the final histological diagnosis in 95 of the 100 patients. The sensitivity was 96% and the specificity was 89% for this prospective series. These results indicate that the computer-assisted diagnosis of pulmonary lesions may have a role in this clinical setting.