Estimating prehospital demand for pediatric antishock garments

Correspondence ESTIMATING PREHOSPITAL DEMAND FOR PEDIATRIC ANTISHOCK GARMENTS To the Editor:-Although emergency medical services systems have developed in most regions of the country, 1 many of the techniques and devices used in the pre-hospital arenat-' were implemented before their full effect had been demonstrated, The pneumatic antishock garment (PASG) is one ofthese devices.v" The PASG was initially developed to prevent peripheral blood pooling and blackouts in airplane pilots during rapid acceleration. In Vietnam, it was used to combat shock in injured soldiers." The PASG splints fractures and tamponades external and internal hemorrhage in the lower extremities and has been useful in the control of hemorrhage resulting from pelvic and femoral fractures.s-? The tamponade affect may also be helpful in controlling intra-abdominal hemorrhage from almost any cause.'? The reported hemodynamic effects include autotransfusion of venous stasis blood from the lower extremities and an increase in afterload thereby improving proximal perfusion to the heart and brain. The volume of blood that is autotransfused is much less than initially thought, and the principal cardiovascular effect is probably caused by the increase in afterload. 11-13 Critics argue that benefits in patient outcome from use of the PASG have not been documented.V The device itself and training for paramedics are expensive, and protocols must be developed, as well as medical control in some areas, for utilization. As possible regulatory changes were being considered in Massachusetts, these concerns arose during consideration of regulations requiring ambulance services to be equipped with the pediatric PASG. The Massachusetts Office of Emergency Medical Services (OEMS) is responsible for certifying all levels of prehospital personnel and, with the Division of Health Care Quality, shares responsibility for establishing equipment requirements for ambulances. The OEMS examined the potential utilization of the pediatric PASG by a retrospective analysis of pediatric trauma data. Our analysis was based on data collected through the Massachusetts Statewide Childhood Injury Prevention Program (SCIPP). The project was one of three funded through the federal office of Maternal and Child Health to determine potential roles for health agencies in preventing childhood injuries. IS The primary objectives of SCIPP were to study the epidemiology of childhood injuries and to implement methods and coordinate efforts to reduce childhood injuries.!' To meet the first objective, a population-based injury surveillance system for children ages 0 to 19 years was undertaken for a three-year period between September I, 1979, and August 31, 1982. The SCIPP established its injury surveillance system in 14 Massachusetts cities and towns representing 5% of the state's pediatric population.f and selected to provide representation of older urban centers, Boston suburbs, and small rural towns. Twenty-three hospitals, which accounted for 93% of the pediatric admissions from these communities, were included in the surveillance system. The SCIPP abstracted a 100% sample of the medical records of all cases of 572

pediatric injuries admitted directly to the hospital or through the emergency department. A 25% sample of injuries requiring only emergency department attention was also included in the data base. Cases were defined as injuries occurring over 36 consecutive months to children ages 0 to 19, living in one of the 14 communities. Injuries were coded according to the International Classification of Diseases, Clinical Modification (lCD-9-CM) codes. This data base was used to project estimates of demand for pediatric PASG. The manufacturer recommends that the device be used on injured patients 117 to 147 cm in height, weighing between 18 and 45 kg, with an age range of 7 to 12 years." We selected patients based on age, as the SCIPP data base included this information but not height and weight. In order to include cases that might meet the weight/ height requirements, we selected boys aged 4 through 12 years and girls aged 5 through 13 years. Our criteria for demand for PASG included cases resulting in death or admission to a hospital with the following injuries: open wounds, crushing injuries, vascular injuries, abdominal injuries, open or closed long-bone fractures of the upper and lower extremities, pelvic fractures, spinal cord injuries, chest trauma, penetrating injuries, traumatic amputations, and shock produced by trauma or anaphylaxis (Table I). The SCIPP data base also recorded the number of children who were transported by ambulance services and by other means, thereby enabling calculation of current demand for the PASG as well as the potential need for its usc. We analyzed how many injuries occurred that met the criteria for potential application of the PASG and how many children with such injuries are transported by ambulance and constitute a population whose needs would be met. There were 19,107 males and 18,827 females in the age groups selected for the analysis. In three years, the SCIPP communities reported 165 cases of injuries that met our criteria for inclusion. Only 39% of the children (n = 65) were transported by ambulance (Table 2). The remaining children were transported by car, other emergency vehicles, or the

TABLE 1. Pediatric Admissions in Massachusetts, Selected Causes for Boys Aged 4 to 12 Years and Girls Aged 5 to 13 Years, 1979-1982* Combined ICO-9-CM Categories Open and closed fractures, excluding hands and feet Penetrating and open wounds All internal injuries Traumatic amputation Injuries to the vascular system Hemothorax or pneumo-hemothorax Crushing injuries Traumatic shock Total for three years of data

Number

(%)

90

( 55)

49

2t

( 30) ( 14) ( 1)

1

(

1)

o

( (

0) 0)

23

o o

165

~ (100)

* There were no cases reported of toxic shock, anaphylactic shock, or anesthesia reaction. t Both cases of amputation were of fingers.

CORRESPONDENCE

TABLE 2. Means of Arrival at Hospital of Children with Specified Injuries, Massachusetts, 1979-1982 Means of Arrival

Three Years

Ambulance Other emergency vehicle Car or public transportation Unknown Total

65 4

78 18 165

Average per Year

21.67 1.33 26.00 6.00 55.00

method of transportation was unknown. This percentage translates to a rate of 14.5 admissions per year per 10,000 children and a rate of 5.7 ambulance transports for this pppulation. In a typical advanced life support area of 150,000 population, we would estimate a population of 19,830 children in the age group 4 to 13 years. Using the expected rates of admissions, we calculated that 28.8 ± 7.5 (estimate ± 2.5 SE) cases per year would meet the previously stated criteria for potentially shock-inducing injury. We also estimated that 11.3 ± 2.5 (estimate ± 2 SE) of the injured would arrive by ambulance in our present EMS system. The vast majority of children with injuries as defined previously would not require advanced treatment using the PASG. There are no well-founded estimates regarding the percentage of this population that might. Although it has not been shown to apply to children, the American College of Surgeons estimates" that 5% of injuries are life-threatening. Applying this figure to an area of 150,000 persons yields a predicted need of 1.44 ± 0.22 (estimate ± 2 SE) applications per year for all admissions. It is important to notice that, as shown in Table I, none of the children in this study were reported to have suffered from shock and that there were no deaths in any of the ICD-9-CM categories searched in this report. Only five deaths were reported for children in this age group in the entire SCIPP data base. The prevention and treatment of childhood injuries is a matter of grave concern, as such injuries have a substantial social and psychological effect on victims and their families. Such injuries might also result in disability and death. The pediatric antishock garment, however, should not be expected to reduce rates of morbidity and mortality greatly. We have presented data on injury incidence that predict a low need for the pediatric PASG. In addition, only 39.4% of the children hospitalized for the injuries included in this study were transported by ambulance, making the actual demand lower. This low incidence of demand is supported by mortality data collected from the Massachusetts Department of Public Health's Division of Health Statistics and Research, which were analyzed in a previous report from SCIPP.14 Their analysis revealed that although trauma was the leading cause of death in patients aged 0 to 19 years from 1969 through 1978, the vast majority of these deaths occurred in age groups or for conditions for which pediatric PASG would not have been of benefit. During the ten-year period, there were 4,852 deaths from injuries to children ages 0 to 19. Approximately 84% of these deaths resulted from injuries occurring to youths aged 0 to 4 years and 13 to 19 years. In general, these children would not fit the manufacturers' criteria for application of the pediatric PASG. Among children aged 6 to 12

years who died of injuries, many deaths involved etiologies for which PASG would not be an appropriate treatment. Of the 788 children aged 6 to 12 years who died during the tenyear period, 143 deaths resulted from drowning, 109 from fire, 47 from suffocation, and four from poisoning. The pediatric PASG would not be applicable in these 303 episodes. Therefore, the number of children who died of injuries for which the pediatric PASG might have been indicated was 485. Of the total group of children aged 0 to 19 years (n = 4,852) who died during the ten-year period, 10% might have benefited from the pediatric PASG. This low figure is more significant when one realizes that approximately 50% of pediatric trauma primarily involves head and neurological trauma. 19.20 The impact of the PASG on survival has only recently been studied. In two large series.t-" no improvement in survival was demonstrated in patients having been resuscitated with the PASG in the field. There are an estimated 100 advanced life support ambulances in the Commonwealth of Massachusetts. The pediatric PASG is purchased for approximately $500 per unit. In addition, the training and skill maintenance would add additional expense. This device would represent a modest additional cost to advanced life support vehicles that would not necessarily result in substantial improvements in public health. Two considerations must be noticed in interpreting these results. First, we were liberal in estimating the number of patients on whom. the pneumatic antishock garment might be applied. Our list of selected injuries included closed fractures to the leg, which accounted for 34.5% of all injured patients (57/165). In most cases, in the absence of other injuries or shock, the chief benefit of PASG would be as an air splint. This splinting capability may be achieved with less expensive devices; therefore, the inclusion of the fracture cases probably produces an overestimate. Secondly, the SeIPp data do not contain measures of severity. Using the ACS criteria," we estimated that the demand rate would be the same for adults and children: 5% of the injuries. This percentage may be much lower than the actual one, and perhaps more accurate estimates are necessary. We predict that use of the pediatric PASG on critically injured pediatric patients would be infrequent. As a result, we anticipate that paramedics would need to complete regular refresher training in its appropriate use. Distressingly, this study points out the failure to utilize ambulances to transport pediatric patients in this state. It is unclear whether this is unique to Massachusetts or perhaps is a more common problem than appreciated in other areas. Clearly public education is essential in this regard in our area and possibly in other EMS systems. CHARLES J. MCCABE, MD ROBERT T. CADIGAN, PhD CAROL E. BUGARIN, MA

Office of Emergency Medical Services CAREY V. AZZARA, MA

Division of Family Health Services Massachusetts Department of Public Health BOStOll, MA 02111

REFERENCES 1. National Academy of Sciences, Division of Medical Sciences, National Research Council. Accidental Death

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AMERICAN JOURNAL OF EMERGENCY MEDICINE. Volume 4, Number 6. November 1986

and Disability, the Neglected Disease of Modern Society. Washington, DC, 1966. 2. Copass MK, Oreskovich MR, Bladorgreen MR, et at Prehospital cardiopulmonary resuscitation of the critically injured patient. Am J Surg 1984;148:20-28. 3. Jacobs LM, Sinclair A, Beiser A. Prehospital advanced life support: benefits in trauma. J Trauma 1984;24:8-13. 4. Trunkey DD. Is ALS necessary for prehospital trauma care? J Trauma 1984;24:86-87. 5. Mackensie RC, Christensen JM, Lewis FR. The prehospital use of external counterpressure: Does MAST make a difference? J Trauma 1984;24:882-887. 6. Mattox KL, Pepe PE, Bickell W. A prospective randomized evaluation for the "MAST" garment in hemorrhagic shock. Abstract presented AAST Boston, September 12, 1985. 7. Cutler BS, Daggett W. Application of the G-suit to the control of hemorrhage in massive trauma. Arch Surg 1971 ;173:511-514. 8. Gaffney FA, Thai ER, Taylor WF. Hemodynamic effects of the medical antishock trousers. J Trauma 1981 ;21:931937. 9. Flint LM, Brown A, Richardson JD, et at Definitive control of bleeding from severe pelvic fractures. Ann Surg 1979; 189:709-716. 10. Pillegra R, Sandberg EC. Control of intractable abdominal bleeding by external counter pressure. JAM A 1979; 241 :708-712. 11. Abraham E, Cobo JC, Bland RD, et at Cardiorespiratory effects of pneumatic trousers in critically ill patients. Arch Surg 1984;119:912-915. 12. Bivins HG, Knapp R, Tiernan C, et at Blood volume displacement with inflation of antishock trousers. Ann Emerg Med 1982:409-412. 13. Niemann JT, Stapczynski JS, Rosborough JP, et at Hemodynamic effects of penumatic external counterpressure . in canine hemorrhagic shock. Ann Emerg Med 1983; 12:661-667. 14. Gallagher SS, Guyer B, Kotelchuck M, et at A strategy for the reduction of childhood injuries in Massachusetts: SCIPP. N Engl J Med 1982;307:1015-1018. 15. Anonymous. Accident prevention and injury control projects directed at children. Pub Health Rep 1980;95:499-500. 16. Gallagher SS, Finison K, Guyer B, et at The incidence of injuries among 87,000 Massachusetts children and adolescents: Results of the 1980-1981 statewide childhood injury prevention program surveillance system. Am J Pub Health 1984;74:1340-1347. 17. Gladiator antishock pants: Instructions for application, operation, and repair. Toledo, Ohio: Jobst Corporation, 1982. 18. Committee on Trauma, American College of Surgeons. Bull Am Call Surg 1983;68:11-18. 19. Holmes MJ, Reyes HM. A critical review of urban pediatric trauma. J Trauma 1984;24:253-255. 20. Mayer T, Walker ML, Johnson D, et at Causes of morbidity and mortality in severe pediatric trauma. JAMA 1981 ;245: 719-721.

EMERGENCY DEPARTMENT THORACOTOMY To tire Editor:- The article by Roberge et til on emergency department thoracotomy (AJEM 1986;4: 129-135) provides 574

some useful information, and is well presented. Two of the comments of the authors, however, require further discussion. The authors' recommendation that thoracotomy not be carried out on "unsalvageable" group IV (dead at the scene) patients may ultimately prove to be justified, as outcome has been relatively dismal in similar patients in a variety of series. Nevertheless, making such a drastic decision on the basis of the very few cases reported in the literature, not to mention the even smaller group of nine patients in the current series, is potentially dangerous. It would seem prudent to continue efforts to salvage all the victims of penetrating trauma (unless available personnel would by doing so have to choose against resuscitating some potentially more salvageable patients) until there is much greater combined experience that confirms this small initial set of data suggesting a dismal outcome in this group of patients. I find the authors' comments in their section entitled "Transportation Analysis" even more disconcerting. There is a great controversy over the question of "scoop and run" versus "field stabilization" for trauma victims, but definitive studies have not yet been performed. Although the small number of patients involved in this series would not allow firm conclusions regardless of the results (and could not be generalized to any patients other than those suffering penetrating trauma with cardiac arrest in the field), it is important to note that the authors have misstated the significance of their findings in an attempt to validate what seems to be their preconceived bias. They tell us that five of seven survivors in their series were brought to the hospital by private vehicle or police car, and thus represent a "scoop and run" situation, as opposed to only two survivors in the ambulance group. On this basis they suggest a superiority of the "scoop and run" approach. This is not so. Five survivors of 22 total patients in the private vehicle group (23%) is statistically extremely far from significant when compared with two survivors of 13 group VII/III patients (15%) in the ambulance group. In fact, since all the survivors in the series (except for one patient with a gunshot wound to the lung) sustained right ventricular injuries, the survival of two of three group VII/III patients with right ventricular injuries brought by ambulance is certainly equivalent to four survivors of eight group 1/lI/III patients with right ventricular injuries brought in with a "scoop and run" approach. No comparisons regarding one variable (such as mode of transportation) are valid unless the different groups are otherwise matched; speculation about survival based on method of transportation to hospital without any attempt to evaluate similarity of patients on the basis of other critical factors, such as weapon use, site of injury, and condition in the field (all of which the authors indicate elsewhere are important determinants of outcome), is invalid. It is unfortunate that the authors thus chose to make assertions about the importance of mode of transportation in the absence of attempts to match other critical variables, and even more so considering the fact that the proposed effect of mode of transportation is not significant statistically even when such (necessary) 'compensation for these other variables is not done. I believe this point is worth making for two reasons. First, it is important that conclusions based on research data be truly supported by those data; one of the most important reasons why many of the articles We all read do not allow us