Martin A. Schreiber

New hemostatic agents in the combat setting

BACKGROUND: Hemorrhage is a leading cause of potentially preventable death in both civilian and military trauma patients. Animal data have shown that hemostatic bandages reduce hemorrhage and improve survival. This article reports recent clinical observations regarding the efficacy and evolution of use of two new hemostatic bandages employed in the global war on terrorism.

Management of patients with anterior abdominal stab wounds: a Western Trauma Association multicenter trial.

BACKGROUND The optimal management of hemodynamically stable, asymptomatic patients with anterior abdominal stab wounds (AASWs) remains controversial. The goal is to identify and treat injuries in a safe, cost-effective manner. Common evaluation strategies include local wound exploration (LWE)/diagnostic peritoneal lavage (DPL), serial clinical assessments (SCAs), and computed tomography (CT) imaging. The purpose of this multicenter study was to evaluate the clinical course of patients managed by the various strategies, to determine whether there are differences in associated nontherapeutic laparotomy (NONTHER LAP), emergency department (ED) discharge, or complication rates. METHODS A multicenter, Institutional Review Board-approved study enrolled patients with AASWs. Management was individualized according to surgeon/institutional protocols. Data on the presentation, evaluation, and clinical course were recorded prospectively. RESULTS Three hundred fifty-nine patients were studied. Eighty-one had indications for immediate LAP, of which 84% were therapeutic. ED D/C was facilitated by LWE, CT, and DPL in 23%, 21%, and 16% of patients, respectively. On the other hand, LAP based on abnormalities on LWE, CT, and DPL were NONTHER in 57%, 24%, and 31% of patients, respectively. Twelve percent of patients selected for SCA ultimately had LAP (33% were NONTHER); there was no apparent morbidity due to delay in intervention. CONCLUSIONS Shock, evisceration, and peritonitis warrant immediate LAP after AASW. Patients without these findings can be safely observed for signs or symptoms of bleeding or hollow viscus injury. To limit the number of hospital admissions, we propose a uniform strategy using LWE to ascertain the depth of penetration; the patient may be safely discharged in the absence of peritoneal violation. Peritoneal penetration, absent evidence of ongoing hemorrhage or hollow viscus injury, should not be considered an indication for LAP, but rather an indication for admission for SCAs. We suggest that a prospective multicenter trial be performed to document the safety and cost-effectiveness of such an approach.

Risk Factors for Respiratory Failure Following Operative Stabilization of Thoracic and Lumbar Spine Fractures

BACKGROUND Respiratory failure is a serious complication that can adversely affect the hospital course and survival of multiply injured patients. Some studies have suggested that delayed surgical stabilization of spine fractures may increase the incidence of respiratory complications. However, the authors of these studies analyzed small sets of patients and did not assess the independent effects of multiple risk factors. METHODS A retrospective cohort study was conducted at a regional level-I trauma center to identify risk factors for respiratory failure in patients with surgically treated thoracic and lumbar spine fractures. Demographic, diagnostic, and procedural variables were identified. The incidence of respiratory failure was determined in an adult respiratory distress syndrome registry maintained concurrently at the same institution. Univariate and multivariate analyses were used to determine independent risk factors for respiratory failure. An algorithm was formulated to predict respiratory failure. RESULTS Respiratory failure developed in 140 of the 1032 patients in the study cohort. Patients with respiratory failure were older; had a higher mean Injury Severity Score (ISS) and Charlson Comorbidity Index Score; had greater incidences of pneumothorax, pulmonary contusion, and thoracic level injury; had a lower mean Glasgow Coma Score (GCS); were more likely to have had a posterior surgical approach; and had a longer mean time from admission to surgical stabilization than the patients without respiratory failure (p < 0.05). Multivariate analysis identified five independent risk factors for respiratory failure: an age of more than thirty-five years, an ISS of > 25 points, a GCS of < or = 12 points, blunt chest injury, and surgical stabilization performed more than two days after admission. An algorithm was created to determine, on the basis of the number of preoperative predictors present, the relative risk of respiratory failure when surgery was delayed for more than two days. CONCLUSIONS Independent risk factors for respiratory failure were identified in an analysis of a large cohort of patients who had undergone operative stabilization of thoracic and lumbar spine fractures. Early operative stabilization of these fractures, the only risk factor that can be controlled by the physician, may decrease the risk of respiratory failure in multiply injured patients.

Early resuscitation intensity as a surrogate for bleeding severity and early mortality in the PROMMTT study.

BACKGROUND The classic definition of massive transfusion, 10 or more units of red blood cells (RBCs) in 24 hours, has never been demonstrated as a valid surrogate for severe hemorrhage and can introduce survival bias. In addition, the definition fails to capture other products that the clinician may have immediately available, and may use, during the initial resuscitation. Assuming that units of resuscitative fluids reflect patient illness, our objective was to identify a rate of resuscitation intensity (RI) that could serve as an early surrogate of sickness for patients with substantial bleeding after injury. METHODS Adult patients surviving at least 30 minutes after admission and receiving one or more RBCs within 6 hours of admission from 10 US Level 1 trauma centers were enrolled in the PRospective Observational Multicenter Major Trauma Transfusion (PROMMTT) study. Total fluid units were calculated as the sum of the number of crystalloid units (1 L = 1 U), colloids (0.5 L = 1 U), and blood products (1 RBC = 1 U, 1 plasma = 1 U, 6 pack platelets = 1 U). Univariable and multivariable logistic regressions were used to evaluate associations between RI and 6-hour mortality, adjusting for age, center, penetrating injury, weighted Revised Trauma Score (RTS), and Injury Severity Score (ISS). RESULTS A total of 1,096 eligible patients received resuscitative fluids within 30 minutes, including 620 transfused with blood products. Despite varying products used, the total fluid RI was similar across all sites (3.2 ± 2.5 U). Patients who received four or more units of any resuscitative fluid had a 6-hour mortality rate of 14.4% versus 4.5% in patients who received less than 4 U. The adjusted odds ratio of 6-hour mortality for patients receiving 4 U or more within 30 minutes was 2.1 (95% confidence interval, 1.2–3.5). CONCLUSION Resuscitation with four or more units of any fluid was significantly associated with 6-hour mortality. This study suggests that early RI regardless of fluid type can be used as a surrogate for sickness and mortality in severely bleeding patients. LEVEL OF EVIDENCE Epidemiologic/prognostic study, level III.

State of the Art of Fluid Resuscitation 2010: Prehospital and Immediate Transition to the Hospital

Abstract : The Prehospital Fluid Conference was sponsored by the US Army Institute of Surgical Research and Combat Casualty Care Research, US Army Medical Research and Materiel Command. Some 65 conferees were invited in January 2010 to review the contemporary guidelines on the use of fluid resuscitation in treating combat casualties, discuss the state of the art of fluid resuscitation for combat casualties, and answer the following questions: - Are current Tactical Combat Casualty Care (TCCC) intravenous (IV) fluid resuscitation guidelines optimal for today? - Which IV fluid should be the top priority for future research? - What are the current indications for fluid resuscitation in the combat trauma patient? - What is the current practice in tactical fluid resuscitation? The objective of this conference was to identify the fluid to be used by the prehospital provider and not to address the needs once definitive hemorrhage control has been achieved. The fluids to be used are those that will be carried into the field on the back of the combat medic or in the vehicle used to transport the medic or the patient (echelon 1 care). There are several definitions of these echelons of care (North Atlantic Treaty Organization [NATO], European forces, etc.). The definitions used in this document are those of the Joint Theater Trauma System. The use of role and echelon can be interchangeable depending on the country of origin, but the terms can vary significantly. Echelon, as used in many/most of Joint Theater Trauma System presentations will be used throughout this document to indicate a level of care facility (see Table 1). Although discussions focused on military needs, it was understood and accepted by the consensus group that many, if not all, of the recommendations could and would be used for civilian prehospital providers with appropriate situational modifications.

Timing of Vaccination Does Not Affect Antibody Response or Survival after Pneumococcal Challenge in Splenectomized Rats

BACKGROUND Pneumococcal vaccination after splenectomy for trauma decreases the incidence of overwhelming postsplenectomy infection. The optimal timing of vaccination has not been established. This study was conducted to determine whether timing of vaccination after splenectomy affects antibody response or survival after pneumococcal challenge. METHODS Sprague-Dawley rats were used for all experiments. Control rats (n=30) were divided into three equal groups and underwent splenectomy followed by sham vaccination 1, 7, or 42 days after splenectomy. Treated rats (n=66) were divided into three equal groups and underwent splenectomy followed by vaccination with polyvalent pneumococcal vaccine 1, 7, or 42 days after splenectomy. All rats then underwent intraperitoneal Streptococcus pneumoniae inoculation with the predetermined lethal dose for 50% of the population 10 days after vaccination. Rats were observed for a 72-hour period after inoculation, and mortality was recorded. Immunoglobulin G and immunoglobulin M antibody titers were determined before vaccination and before inoculation to determine antibody response. RESULTS Mortality was greater in the control group than in the treatment group (21 of 30 [70%] vs. 2 of 64 [3%]; p < 0.01). There were no differences in mortality within either the control group (1 day, 6 of 10; 7 days, 7 of 10; 42 days, 8 of 10; p=0.62) or the treatment group (1 day, 0 of 21; 7 days, 0 of 21; 42 days, 2 of 22; p=0.14). Immunoglobulin G and immunoglobulin M antibody responses were greater in vaccinated than in nonvaccinated rats. There was no effect of timing of vaccination on antibody response. CONCLUSION Pneumococcal vaccine reduces mortality from postsplenectomy infection. Timing of vaccination after splenectomy does not affect survival from a pneumococcal challenge or antibody response in rats. This study supports the practice of administering vaccine within 24 hours of splenectomy when vaccine cannot be administered before surgery.

U.S. army air ambulance operations in El Paso, Texas: A descriptive study and system review☆☆☆

Objectives. To analyze a high-volume military air ambulance unit and review the U.S. Army air medical transport system and Military Assistance to Safety and Traffic (MAST) program. Methods. The setting was a remote medical system with numerous ground emergency medical services. All patients transported between January 1, 1996, and February 28, 1998, were included. Patients who were dead on scene or for whom records were unavailable were excluded. A retrospective review of transport and available inpatient records was conducted. Results. Five hundred seventeen patients were transported during the study period; 461 patients met inclusion criteria (89%). Of these, 70% were classified as trauma; 30% possessed medical or other surgical diagnoses. Prehospital responses numbered 71.6%, while 28.4% were interhospital transfers. Missions averaged 23.4 minutes per flight, with no major aircraft mishaps. Prehospital utilization review showed appropriate use; 35% of interhospital trauma and 11% of interhospital nontrauma missions were staffed inadequately by these criteria. Time intervals, procedures, and program impact are discussed. Conclusion. This and similar units participating in the MAST program provide effective air transport in settings underserved by civilian programs. Quality and wartime readiness could be improved by centralized medical direction, treatment and transfer protocols, and enhanced training of medics. Further investigations of the clinical impact of advanced training and a two-medic aircrew model are warranted.

Laboratory measures of coagulation among trauma patients on NOAs: results of the AAST-MIT

Background Warfarin is associated with poor outcomes after trauma, an effect correlated with elevations in the international normalized ratio (INR). In contrast, the novel oral anticoagulants (NOAs) have no validated laboratory measure to quantify coagulopathy. We sought to determine if use of NOAs was associated with elevated activated partial thromboplastin time (aPTT) or INR levels among trauma patients or increased clotting times on thromboelastography (TEG). Methods This was a post-hoc analysis of a prospective observational study across 16 trauma centers. Patients on dabigatran, rivaroxaban, or apixaban were included. Laboratory data were collected at admission and after reversal. Admission labs were compared between medication groups. Traditional measures of coagulopathy were compared with TEG results using Spearman’s rank coefficient for correlation. Labs before and after reversal were also analyzed between medication groups. Results 182 patients were enrolled between June 2013 and July 2015: 50 on dabigatran, 123 on rivaroxaban, and 34 apixaban. INR values were mildly elevated among patients on dabigatran (median 1.3, IQR 1.1–1.4) and rivaroxaban (median 1.3, IQR 1.1–1.6) compared with apixaban (median 1.1, IQR 1.0–1.2). Patients on dabigatran had slightly higher than normal aPTT values (median 35, IQR 29.8–46.3), whereas those on rivaroxaban and apixaban did not. Fifty patients had TEG results. The median values for R, alpha, MA and lysis were normal for all groups. Prothrombin time (PT) and aPTT had a high correlation in all groups (dabigatran p=0.0005, rivaroxaban p<0.0001, and apixaban p<0.0001). aPTT correlated with the R value on TEG in patients on dabigatran (p=0.0094) and rivaroxaban (p=0.0028) but not apixaban (p=0.2532). Reversal occurred in 14%, 25%, and 18% of dabigatran, rivaroxaban, and apixaban patients, respectively. Both traditional measures of coagulopathy and TEG remained within normal limits after reversal. Discussion Neither traditional measures of coagulation nor TEG were able to detect coagulopathy in patients on NOAs. Level of evidence Level IV.