Michael Stein

Blast Injuries: Bus Versus Open-air Bombings--a Comparative Study of Injuries in Survivors of Open-air Versus Confined-space Explosions

OBJECTIVESnTo compare injury patterns resulting from explosions in the open air versus within confined spaces.nnnMETHODSnMedical charts of 297 victims of four bombing events were analyzed. Two explosions occurred in the open air and two inside buses. Similar explosive devices were applied in all four incidents. The incidence of primary blast injuries, significant penetrating trauma (Abbreviated Injury Scale score > or = 2), burns, Injury Severity Score, Revised Trauma Score, and mortality were compared between the two populations.nnnRESULTSnA total of 204 casualties were involved in open-air bombings, 15 of whom died (7.8%). Ninety-three victims were involved in bus bombings, 46 of whom died (49%). The difference in mortality rate was highly significant, p < 0.00001. Primary blast injuries were observed in 25 and 31 victims (34.2% and 77.5% of admitted victims), respectively (p = 0.00003). Median Injury Severity Score was 4 versus 18, respectively (p < 0.0001).nnnCONCLUSIONnExplosions in confined spaces are associated with a higher incidence of primary blast injuries, with more severe injuries and with a higher mortality rate in comparison with explosions in the open air.

Abdominal injuries without hemoperitoneum: a potential limitation of focused abdominal sonography for trauma (FAST)

BACKGROUNDnFocused abdominal sonography for trauma (FAST) relies on hemoperitoneum to identify patients with injury. Blunt trauma victims (BTVs) with abdominal injury, but without hemoperitoneum, on admission are at risk for missed injury.nnnMETHODSnClinical, radiologic, and FAST data were collected prospectively on BTVs over a 12-month period. All patients with FAST-negative for hemoperitoneum were further analyzed. Examination findings and associated injuries were evaluated for association with abdominal lesions.nnnRESULTSnOf 772 BTVs undergoing FAST, 52 (7%) had abdominal injury. Fifteen of 52 (29%) had no hemoperitoneum by admission computed tomographic scan, and all had FAST interpreted as negative. Four patients with splenic injury underwent laparotomy. Six other patients with splenic injury and five patients with hepatic injury were managed nonoperatively. Clinical risk factors significantly associated with abdominal injury in BTVs without hemoperitoneum include: abrasion, contusion, pain, or tenderness in the lower chest or upper abdomen; pulmonary contusion; lower rib fractures; hemo- or pneumothorax; hematuria; pelvic fracture; and thoracolumbar spine fracture.nnnCONCLUSIONSnUp to 29% of abdominal injuries may be missed if BTVs are evaluated with admission FAST as the sole diagnostic tool. Consideration of examination findings and associated injuries should reduce the risk of missed abdominal injury in BTVs with negative FAST results.

Gunshot and Explosion Injuries: Characteristics, Outcomes, and Implications for Care of Terror-Related Injuries in Israel

Context:An increase of terror-related activities may necessitate treatment of mass casualty incidents, requiring a broadening of existing skills and knowledge of various injury mechanisms. Objective:To characterize and compare injuries from gunshot and explosion caused by terrorist acts. Methods:A retrospective cohort study of patients recorded in the Israeli National Trauma Registry (ITR), all due to terror-related injuries, between October 1, 2000, to June 30, 2002. The ITR records all casualty admissions to hospitals, in-hospital deaths, and transfers at 9 of the 23 trauma centers in Israel. All 6 level I trauma centers and 3 of the largest regional trauma centers in the country are included. The registry includes the majority of severe terror-related injuries. Injury diagnoses, severity scores, hospital resource utilization parameters, length of stay (LOS), survival, and disposition. Results:A total of 1155 terror-related injuries: 54% by explosion, 36% gunshot wounds (GSW), and 10% by other means. This paper focused on the 2 larger patient subsets: 1033 patients injured by terror-related explosion or GSW. Seventy-one percent of the patients were male, 84% in the GSW group and 63% in the explosion group. More than half (53%) of the patients were 15 to 29 years old, 59% in the GSW group and 48% in the explosion group. GSW patients suffered higher proportions of open wounds (63% versus 53%) and fractures (42% versus 31%). Multiple body-regions injured in a single patient occurred in 62% of explosion victims versus 47% in GSW patients. GSW patients had double the proportion of moderate injuries than explosion victims. Explosion victims have a larger proportion of minor injuries on one hand and critical to fatal injuries on the other. LOS was longer than 2 weeks for 20% (22% in explosion, 18% in GSW). Fifty-one percent of the patients underwent a surgical procedure, 58% in the GSW group and 46% in explosion group. Inpatient death rate was 6.3% (65 patients), 7.8% in the GSW group compared with 5.3% in the explosion group. A larger proportion of gunshot victims died during the first day (97% versus 58%). Conclusions:GSW and injuries from explosions differ in the body region of injury, distribution of severity, LOS, intensive care unit (ICU) stay, and time of inpatient death. These findings have implications for treatment and for preparedness of hospital resources to treat patients after a terrorist attack in any region of the world. Tailored protocol for patient evaluation and initial treatment should differ between GSW and explosion victims. Hospital organization toward treating and admitting these patients should take into account the different arrival and injury patterns.

Intravenous rFVIIa Administered for Hemorrhage Control in Hypothermic Coagulopathic Swine with Grade V Liver Injuries

BACKGROUNDnIntravenous administration of recombinant activated human clotting factor VII (rFVIIa) has been used successfully to prevent bleeding in hemophilia patients undergoing elective surgery, but not in previously normal trauma patients. This study was conducted to determine whether rFVIIa was a useful adjunct to gauze packing for decreasing blood loss from grade V liver injuries in hypothermic and coagulopathic swine.nnnMETHODSnAll animals (n = 10, 35 +/- 2 kg) underwent a 60% isovolemic exchange transfusion with 6% hydroxyethyl starch and were cooled to 33 degrees C core temperature. The swine then received a grade V liver injury and 30 seconds later, either 180 microg/kg rFVIIa, or saline control. All animals were gauze packed 30 seconds after injury and resuscitated 5.5 minutes after injury with lactated Ringers solution to their preinjury mean arterial pressure. Posttreatment blood loss, mean arterial pressure, resuscitation volume, and clotting studies were monitored for 1 hour. Histology of lung, kidney, and small bowel were obtained to evaluate for the presence of microvascular thrombi.nnnRESULTSnAt the time of injury, core temperature was 33.3 degrees +/- 0.4 degrees C, hemoglobin was 6 +/- 0.7 g/dL, prothrombin time was 19.1 +/- 1.0 seconds, activated partial thromboplastin time was 29.0 +/- 4.8 seconds, fibrinogen was 91 +/- 20 mg/dL, and platelets were 221 +/- 57 x 105/mL, with no differences between groups (p > 0.05). Clotting factor levels confirmed a coagulopathy at the preinjury point. The posttreatment blood loss was less (p < 0.05) in group 1 (527 +/- 323 mL), than in group 2 (976 +/- 573 mL). The resuscitation volume was not different (p > 0.05). One-hour survival in both groups was 100%. Compared with the control group, rFVIIa increased the circulating levels of VIIa and, despite hypothermia, shortened the prothrombin time 5 minutes after injection (p < 0.05). Laboratory evaluation revealed no systemic activation of the clotting cascade. Postmortem evaluation revealed no evidence of large clots in the hepatic veins or inferior vena cava, or microscopic thrombi in lung, kidney, or small intestine.nnnCONCLUSIONnrFVIIa reduced blood loss and restored abnormal coagulation function when used in conjunction with liver packing in hypothermic and coagulopathic swine. No adverse effects were identified.

How does casualty load affect trauma care in urban bombing incidents? A quantitative analysis

BACKGROUNDnThe aim of this modeling study was to examine how casualty load affects the level of trauma care in multiple casualty incidents and to define the surge capacity of the hospital trauma assets.nnnMETHODSnThe disaster plan of a U.S. Level I trauma center was translated into a computer model and challenged with simulated casualties based on 223 patients from 22 bombing incidents treated at an Israeli hospital. The model assigns providers and facilities to casualties and computes the level of care for each critical casualty from six variables that reflect the composition of the trauma team and access to facilities.nnnRESULTSnThe model predicts a sigmoid-shaped relationship between casualty load and the level of care, with the upper flat portion of the curve corresponding to the surge capacity of the trauma assets of the hospital. This capacity is 4.6 critical patients per hour using immediately available assets. A fully deployed disaster plan shifts the curve to the right, increasing the surge capacity to 7.1. Overtriage rates of 50% and 75% shift the curve to the left, decreasing the surge capacity to 3.8 and 2.7, respectively.nnnCONCLUSIONnThis model defines the quantitative relationship between an increasing casualty load and gradual degradation of the level of trauma care in multiple casualty incidents, and defines the surge capacity of the hospital trauma assets as a rate of casualty arrival rather than a number of beds. The study demonstrates the value of dynamic computer modeling as an important tool in disaster planning.

Surgical resource utilization in urban terrorist bombing: a computer simulation.

BACKGROUNDnThe objective of this study was to analyze the utilization of surgical staff and facilities during an urban terrorist bombing incident.nnnMETHODSnA discrete-event computer model of the emergency room and related hospital facilities was constructed and implemented, based on cumulated data from 12 urban terrorist bombing incidents in Israel.nnnRESULTSnThe simulation predicts that the admitting capacity of the hospital depends primarily on the number of available surgeons and defines an optimal staff profile for surgeons, residents, and trauma nurses. The major bottlenecks in the flow of critical casualties are the shock rooms and the computed tomographic scanner but not the operating rooms. The simulation also defines the number of reinforcement staff needed to treat noncritical casualties and shows that radiology is the major obstacle to the flow of these patients.nnnCONCLUSIONnComputer simulation is an important new tool for the optimization of surgical service elements for a multiple-casualty situation.

Prehospital blood transfusion in prolonged evacuation

BACKGROUNDnPrehospital blood transfusion for hemorrhaging trauma patients has been used infrequently and is controversial. Currently, there is no satisfactory nonsanguineous fluid therapy for use during prolonged transport, such as in military or rural trauma.nnnMETHODSnWe retrospectively reviewed prehospital data and hospital charts of all trauma patients in Israel who had received prehospital blood transfusion during a period of 30 months.nnnRESULTSnForty patients received 60 U of Rh-positive type O packed red blood cells. Mean time from injury to hospital admission was 120 minutes. Twenty-one of 31 patients admitted to the hospital alive (68%) received additional blood transfusions during the initial resuscitation phase, justifying the prehospital transfusion. Of nine documented admissions with hemoglobin of less than 7 g/dL, one patient died of exsanguination. There was one case of a minor adverse reaction that could be attributed to prehospital transfusion.nnnCONCLUSIONnPrehospital blood transfusion is justified in certain trauma patients, especially when long prehospital transport is required. Blood may be safely maintained and used by physicians with little experience in care of major trauma.

Triage and trauma workload in mass casualty: a computer model.

BACKGROUNDnThe aim of this study was to quantitatively analyze the impact of hospital triage on the workload of trauma teams in the Emergency Department during a mass casualty incident, using a computer model.nnnMETHODSnThe inflow and triage of casualties into an Emergency Department with 5 trauma teams was modeled using the Monte Carlo method. Triage was represented as a binary classification task performed in one or two sequential steps. The input variables were triage accuracy (specificity and sensitivity) and casualty load, and the key output variable was the time to saturation (TTS) of the trauma teams, which was computed from the available and needed team minutes.nnnRESULTSnThe relationship between an increasing casualty load and the TTS describes a sigmoid-shaped curve. Improving triage accuracy extends the TTS and shifts the curve to the right. Switching to sequential competent triage (80% accuracy) results in TTS that is similar to perfect single-step triage (100% accuracy) but at the cost of investing less team time in urgent casualties. The optimal ratio of trauma teams to urgent casualties in sequential mode is 1:8, indicating that the treatment of urgent casualties must be delegated to reinforcement staff.nnnCONCLUSIONSnThis study introduces innovative tools for quantitative analysis of hospital triage in mass casualty incidents and shows how triage accuracy and mode affect the ability of trauma teams to cope with heavy casualty loads. These tools can be used to optimize the hospital response to future threats.

Antithrombin III and trauma patients : factors that determine low levels

A prospective (cohort) study was conducted to determine the incidence of low antithrombin III (AT III) levels and the association with selected clinical variables in adult trauma patients. One hundred sixty AT III levels were obtained on 50 consecutive trauma admissions to a community-based level I trauma center. Antithrombin III levels were drawn as soon after admission as possible and every other day thereafter. Thirty-one patients (62%) had at least one low AT III level (< 80%), whereas 15 concurrently drawn control levels were all > or = 90%. Low AT III levels were more common in patients with one or more of the following: base deficit less than -4 (39% vs. 0, p = 0.002); Injury Severity Score > 15 (48% vs. 16%, p = 0.04); and blood transfusion (32% vs. 5%, p = 0.04). All other variables (shock, surgical intervention, subcutaneous heparin, and sequential compression devices) were not statistically significant, although all six patients with shock had low levels. In conclusion, over 60% of adult trauma patients had low AT III levels at some time during hospitalization and these patients were clearly more severely injured. Further studies are required to determine if these patients are more susceptible to thromboembolic phenomena.

Extracorporeal life support in patients with multiple injuries and severe respiratory failure: a single-center experience?

BACKGROUND The use of extracorporeal life support in trauma casualties is limited by concerns regarding hemorrhage, particularly in the presence of traumatic brain injury (TBI). We report the use of extracorporeal membrane oxygenation (ECMO)/interventional lung assist (iLA) as salvage therapy in trauma patients. High-flow technique without anticoagulation was used in patients with coagulopathy or TBI. METHODS Data were collected from all adult trauma patients referred to one center for ECMO/iLA treatment owing to severe hypoxemic respiratory failure. RESULTS Ten casualties had a mean (SD) Injury Severity Score (ISS) of 50.3 (10.5) (mean [SD] age, 29.8 [7.7] years; 60% male) and were supported 9.5 (4.5) days on ECMO (n = 5) and 7.6 (6.5) days on iLA (n = 5). All experienced blunt injury with severe chest injuries, including one cardiac perforation. Most were coagulopathic before initiation of ECMO/iLA support. Among the seven patients with TBI, four had active intracranial hemorrhage. Complications directly related to support therapy were not lethal; these included hemorrhage from a cannulation site (n = 1), accidental removal of a cannula (n = 1), and pressure sores (n = 3). Deaths occurred owing to septic (n = 2) and cardiogenic shock (n = 1). Survival rates were 60% and 80% on ECMO and iLA, respectively. Follow-up of survivors detected no neurologic deterioration. CONCLUSION ECMO/iLA therapy can be used as a rescue therapy in adult trauma patients with severe hypoxemic respiratory failure, even in the presence of coagulopathy and/or brain injury. The benefits of rewarming, acid-base correction, oxygenation, and circulatory support must be weighed individually against the risk of hemorrhage. Further research should determine whether ECMO therapy also confers survival benefit. LEVEL OF EVIDENCE Therapeutic study, level V.