Matthew Bradley

Independent Predictors of Enteric Fistula and Abdominal Sepsis After Damage Control Laparotomy: Results From the Prospective AAST Open Abdomen Registry

IMPORTANCE Enterocutaneous fistula (ECF), enteroatmospheric fistula (EAF), and intra-abdominal sepsis/abscess (IAS) are major challenges for surgeons caring for patients undergoing damage control laparotomy after trauma. OBJECTIVE To determine independent predictors of ECF, EAF, or IAS in patients undergoing damage control laparotomy after trauma, using the AAST Open Abdomen Registry. DESIGN The AAST Open Abdomen registry of patients with an open abdomen following damage control laparotomy was used to identify patients who developed ECF, EAF, or IAS and to compare these patients with those without these complications. Univariate analyses were performed to compare these groups of patients. Variables from univariate analyses differing at P < .20 were entered into a stepwise logistic regression model to identify independent risk factors for ECF, EAF, or IAS. SETTING Fourteen level I trauma centers. PARTICIPANTS A total of 517 patients with an open abdomen following damage control laparotomy. MAIN OUTCOMES AND MEASURES Complication of ECF, EAF, or IAS. RESULTS More patients in the ECF/EAF/IAS group than in the group without these complications underwent bowel resection (63 of 111 patients [57%] vs 133 of 406 patients [33%]; P < .001). Within the first 48 hours after surgery, the ECF/EAF/IAS group received more colloids (P < .03) and total fluids (P < .03) than did the group without these complications. The ECF/EAF/IAS group underwent almost twice as many abdominal reexplorations as did the group without these complications (mean [SD] number, 4.1 [4.1] vs 2.2 [3.4]; P < .001). After multivariate analysis, the independent predictors of ECF/EAF/IAS were a large bowel resection (adjusted odds ratio [AOR], 3.56 [95% CI, 1.88-6.76]; P < .001), a total fluid intake at 48 hours of between 5 and 10 L (AOR, 2.11 [95% CI, 1.15-3.88]; P = .02) or more than 10 L (AOR, 1.93 [95% CI, 1.04-3.57]; P = .04), and an increasing number of reexplorations (AOR, 1.14 [95% CI, 1.06-1.21]; P < .001). CONCLUSIONS AND RELEVANCE Large bowel resection, large-volume fluid resuscitation, and an increasing number of abdominal reexplorations were statistically significant predictors of ECF, EAF, or IAS in patients with an open abdomen after damage control laparotomy.

Risk factors for post-traumatic pneumonia in patients with retained haemothorax: Results of a prospective, observational AAST study

INTRODUCTION Retained haemothorax (RH) is a problematic sequela of thoracic trauma, reported in up to 20% of patients following chest injury. RH is associated with a higher severity of thoracic trauma and may portend the onset of other serious post-traumatic complications, including pneumonia. The development of pneumonia has previously been reported to be as high as 19.5% in the setting of traumatic RH. The purpose of this study was to identify risk factors for the development of pneumonia as a complication in RH. METHODS We utilized the American Association for the Surgery of Trauma Post-Traumatic Retained Haemothorax database. Patients with post-traumatic RH were prospectively enrolled from 2009 to 2011. Inclusion criteria were placement of a thoracostomy tube within 24h of admission for the evacuation of pneumothorax or haemothorax and subsequent chest computed tomography scan chest showing RH. Patients treated with thoracotomy before placement of tube thoracostomy were excluded. For univariate analysis, the Chi-square test with Yates correction was used for comparison of categorical risk factors and the Students t-test or the Mann-Whitney test for comparison of continuous risk factors. To identify independent risk factors for the development of pneumonia, variables from the univariate analysis significant at p<0.2 were entered into a forward logistic regression model. Adjusted odds ratio and 95% confidence intervals (CI) were derived. RESULTS 328 patients with post-traumatic RH from 20 United States centres were enrolled. After stepwise regression analysis, ISS>25 (adjusted OR: 7.1; 95% CI: 3.1, 16.4; p<0.001), blunt mechanism of injury (adjusted OR: 3.5; 95% CI: 1.7, 7.2; p=0.001), and failure to administer peri-procedural antibiotics on the initial thoracostomy tube placement (adjusted OR: 2.6; 95% CI: 1.30, 5.4; p=0.01) were found to be independent predictors of the pneumonia in patients with post-traumatic RH. CONCLUSIONS To our knowledge, our current study is the largest attempt to identify the independent predictors for pneumonia in this population. Our data show that elevated ISS, blunt thoracic trauma, and failure to administer peri-procedural antibiotics on tube thoracostomy placement are the statistically significant independent risk factors.

Open chest cardiac massage offers no benefit over closed chest compressions in patients with traumatic cardiac arrest.

BACKGROUND Open chest cardiac massage (OCCM) is a commonly performed procedure after traumatic cardiac arrest (TCA). OCCM has been reported to be superior to closed chest compressions (CCC) in animal models and in non-TCA. The purpose of this study is to prospectively compare OCCM versus CCC in TCA using end-tidal carbon dioxide (ETCO2), the criterion standard for determining the effectiveness of chest compressions and detection of return of spontaneous circulation (ROSC), as the surrogate for cardiac output and marker for adequacy of resuscitation. METHODS This prospective observational study enrolled patients over a 9-month period directly presenting to a level 1 trauma center after TCA. Continuous high-resolution ETCO2 measurements were collected every 6 seconds for periods of CCC and OCCM, respectively. Patients receiving CCC only were compared with patients receiving CCC followed by OCCM. Students t tests were used to compare ETCO2 within and between groups. RESULTS Thirty-three patients were enrolled (16 OCCM, 17 CCC-only). Mean time of CCC before OCCM was 66 seconds. Within the OCCM group, final, peak, mean, and median ETCO2 levels significantly increased when comparing the initial CCC period to the OCCM interval. Using a time-matched comparison, significant increases were observed in the final and peak but not mean and median values when comparing the first minute of CCC to the remaining time in the CCC-only group. However, when periods of OCCM were compared with equivalent periods of CCC-only, there were no differences in the initial, final, peak, mean, or median ETCO2 values. Correspondingly, no difference in rates of ROSC was observed between groups (OCCM 23.5% vs. CCC 38.9%; p = 0.53). CONCLUSION Although we could not control for confounders, we found no significant improvement in ETCO2 or ROSC with OCCM. With newer endovascular techniques for aortic occlusion, thoracotomy solely for performing OCCM provides no benefit over CCC. LEVEL OF EVIDENCE Therapeutic study, level III.

Cervical Spinal Clearance: A Prospective Western Trauma Association Multi-Institutional Trial.

BACKGROUND For blunt trauma patients who have failed the NEXUS (National Emergency X-Radiography Utilization Study) low-risk criteria, the adequacy of computed tomography (CT) as the definitive imaging modality for clearance remains controversial. The purpose of this study was to prospectively evaluate the accuracy of CT for the detection of clinically significant cervical spine (C-spine) injury. METHODS This was a prospective multicenter observational study (September 2013 to March 2015) at 18 North American trauma centers. All adult (≥18 years old) blunt trauma patients underwent a structured clinical examination. NEXUS failures underwent a CT of the C-spine with clinical follow-up to discharge. The primary outcome measure was sensitivity and specificity of CT for clinically significant injuries requiring surgical stabilization, halo, or cervical-thoracic orthotic placement using the criterion standard of final diagnosis at the time of discharge, incorporating all imaging and operative findings. RESULTS Ten thousand seven hundred sixty-five patients met inclusion criteria, 489 (4.5%) were excluded (previous spinal instrumentation or outside hospital transfer); 10,276 patients (4,660 [45.3%] unevaluable/distracting injuries, 5,040 [49.0%] midline C-spine tenderness, 576 [5.6%] neurologic symptoms) were prospectively enrolled: mean age, 48.1 years (range, 18–110 years); systolic blood pressure 138 (SD, 26) mm Hg; median, Glasgow Coma Scale score, 15 (IQR, 14–15); Injury Severity Score, 9 (IQR, 4–16). Overall, 198 (1.9%) had a clinically significant C-spine injury requiring surgery (153 [1.5%]) or halo (25 [0.2%]) or cervical-thoracic orthotic placement (20 [0.2%]). The sensitivity and specificity for clinically significant injury were 98.5% and 91.0% with a negative predictive value of 99.97%. There were three (0.03%) false-negative CT scans that missed a clinically significant injury, all had a focal neurologic abnormality on their index clinical examination consistent with central cord syndrome, and two of three scans showed severe degenerative disease. CONCLUSIONS For patients requiring acute imaging for their C-spine after blunt trauma, CT was effective for ruling out clinically significant injury with a sensitivity of 98.5%. For patients with an abnormal neurologic examination as the trigger for imaging, there is a small but clinically significant incidence of a missed injury, and further imaging with magnetic resonance imaging is warranted. LEVEL OF EVIDENCE Diagnostic tests, level II.

Indirect signs of blunt duodenal injury on computed tomography: Is non-operative management safe?

INTRODUCTION Clear signs of duodenal injury (DI) such as pneumoperitoneum and/or oral contrast extravasation mandate laparotomy. Management when computed tomography (CT) reveals indirect evidence of DI namely duodenal hematoma or periduodenal fluid is unclear. We evaluated the utility of indirect signs to identify DI and the success of expected management, hypothesizing patients with indirect evidence of DI on CT can be safely managed non-operatively. METHODS We retrospectively reviewed patients with a computed tomography (CT) scan with periduodenal hematoma or periduodenal fluid treated between January 2003 and January 2013 at a level 1 Trauma Center. Demographics, injury characteristics, laboratory values, injury severity scores (ISS), and outcome measures were recorded. Patients having immediate laparotomy were compared to those initially managed nonoperatively. RESULTS We identified 74 patients with indirect signs of DI, with 35 patients (47%) undergoing immediate operative exploration and 39 (53%) initially managed non-operatively. Lactate (4.5 mg/dL, standard deviation (SD) 2.1 vs 3.1 mg/dL, SD 1.4, p<0.001), ISS (median (IQR) 34 (27-44) vs. 24 (17-34), p=0.002) and abdominal AIS (3 (3-4) vs 2 (2-3), p<0.001) were higher in those with immediate operation. The incidence of DI requiring operative repair was 11% (8 of 74). Six of 35 (17%) explored urgently had a DI requiring repair while 29 of 35 (83%) had no DI or minor injury not requiring surgical therapy. Of those managed non-operatively, 7 of 39 (18%) failed observation but only two (5%) required duodenal repair. There was no significant difference in intensive care unit (ICU) (10.2 days, standard error [SE] 2.1 vs 9.7 days, SE 4.8, p=0.93) or hospital (22.5 days, SE 3.8 vs 23.6 days, SE 8.5, p=0.91) length of stay between those operated on immediately and those that failed non-operative management when adjusted for age, sex, and ISS. There was no mortality in the non-operative group related to an intra-abdominal injury. CONCLUSION Observation of patients with indirect sign of DI fails in about 20% of patients, but failure rate due to DI is low at 5%. Conservative management in appropriately selected patients is reasonable with close observation.

Nonsteroidal anti-inflammatory drugs may affect cytokine response and benefit healing of combat-related extremity wounds

Background. After adequate operative debridement and antimicrobial therapies, combat‐related extremity wounds that either heal or fail are both associated with a distinct inflammatory response. Short‐term use of nonsteroidal anti‐inflammatory drugs in postoperative pain management may affect this response and, by consequence, the healing potential of these wounds. We investigated whether patients treated with nonsteroidal anti‐inflammatory drugs had a distinct inflammatory response; different rates of critical colonization, defined as >105 colony forming units on quantitative bacteriology; and healing potential. Methods. We retrospectively reviewed the records of 73 patients with combat‐related extremity wounds. Patients were separated into 2 groups: those who received nonsteroidal anti‐inflammatory drugs during the debridement period (nonsteroidal anti‐inflammatory drugs group, N = 17) and those who did not (control group; N = 56). Serum and wound tissue samples collected during each operative debridement were measured for 32 known cytokines and tested for quantitative bacteriology, respectively. We compared cytokine concentrations between groups and then designed a logistic regression model to identify variables associated with successful wound healing, while controlling for known confounders. Results. Despite similar demographics and wound characteristics, the nonsteroidal anti‐inflammatory drugs group had significant lesser concentrations of inflammatory cytokines, interleukin‐2, interleukin‐6, interleukin‐8, and monocyte chemoattractant protein‐1. On multivariate analysis, nonsteroidal anti‐inflammatory drug treatment emerged as a predictor of successful wound healing after controlling for known confounders such as wound size, tobacco use, Acute Physiology and Chronic Health Evaluation II score, and critical colonization. Conclusion. Treatment with nonsteroidal anti‐inflammatory drugs for postoperative pain management after major combat‐related extremity trauma is associated with lesser concentrations of inflammatory cytokines and may contribute to a more favorable inflammatory response leading to successful wound healing.

Host responses to concurrent combined injuries in non-human primates

BackgroundMulti-organ failure (MOF) following trauma remains a significant cause of morbidity and mortality related to a poorly understood abnormal inflammatory response. We characterized the inflammatory response in a non-human primate soft tissue injury and closed abdomen hemorrhage and sepsis model developed to assess realistic injury patterns and induce MOF.MethodsAdult male Mauritan Cynomolgus Macaques underwent laparoscopy to create a cecal perforation and non-anatomic liver resection along with a full-thickness flank soft tissue injury. Treatment consisted of a pre-hospital phase followed by a hospital phase after 120 minutes. Blood counts, chemistries, and cytokines/chemokines were measured throughout the study. Lung tissue inflammation/apoptosis was confirmed by mRNA quantitative real-time PCR (qPCR), H&E, myeloperoxidase (MPO) and TUNEL staining was performed comparing age-matched uninjured controls to experimental animals.ResultsTwenty-one animals underwent the protocol. Mean percent hepatectomy was 64.4 ± 5.6; percent blood loss was 69.0 ± 12.1. Clinical evidence of end-organ damage was reflected by a significant elevation in creatinine (1.1 ± 0.03 vs. 1.9 ± 0.4, p=0.026). Significant increases in systemic levels of IL-10, IL-1ra, IL-6, G-CSF, and MCP-1 occurred (11-2986-fold) by 240 minutes. Excessive pulmonary inflammation was evidenced by alveolar edema, congestion, and wall thickening (H&E staining). Concordantly, amplified accumulation of MPO leukocytes and significant pulmonary inflammation and pneumocyte apoptosis (TUNEL) was confirmed using qRT-PCR.ConclusionWe created a clinically relevant large animal multi-trauma model using laparoscopy that resulted in a significant systemic inflammatory response and MOF. With this model, we anticipate studying systemic inflammation and testing innovative therapeutic options.

Evaluation of Military Use of Tranexamic Acid and Associated Thromboembolic Events

Importance Since publication of the CRASH-2 and MATTERs studies, the US military has included tranexamic acid (TXA) in clinical practice guidelines. While TXA was shown to decrease mortality in trauma patients requiring massive transfusion, improper administration and increased risk of venous thromboembolism remain a concern. Objective To determine the appropriateness of TXA administration by US military medical personnel based on current Joint Trauma System clinical practice guidelines and to determine if TXA administration is associated with venous thromboembolism. Design, Setting, and Participants This cohort study of US military casualties in US military combat support hospitals in Afghanistan and a single US-based tertiary military treatment facility within the continental United States was conducted from 2011 to 2015, with follow-up through initial hospitalization and readmissions. Exposures Data collected for all patients included demographic information as well as Injury Severity Score; receipt of blood products, TXA, and/or a massive transfusion; and admission hemodynamics. Main Outcomes and Measures Variance from guidelines in TXA administration and venous thromboembolism. Tranexamic acid overuse was defined as a hemodynamically stable patient receiving TXA but not a massive transfusion, underuse was defined as a patient receiving a massive transfusion but not TXA, and TXA administration was considered delayed when given more than 3 hours after injury. Results Of the 455 identified patients, 443 (97.4%) were male, and the mean (SD) age was 25.3 (4.8) years. A total of 173 patients (38.0%) received a massive transfusion, and 139 (30.5%) received TXA in theater. Overuse occurred in 18 of 282 patients (6.4%) and underuse in 46 of 173 (26.6%) receiving massive transfusions, and delayed administration was found in 6 of 145 patients (4.3%) receiving TXA. Overuse increased at 3.3% per quarter (95% CI, 4.0-9.9; P < .001; R2 = 0.340) and underuse decreased at −4.4% per quarter (95% CI, −4.5 to −3.6; P < .001; R2 = 0.410). Tranexamic acid administration was an independent risk factor for venous thromboembolism (odds ratio, 2.58; 95% CI, 1.20-5.56; P = .02). Conclusions and Relevance Military medical personnel decreased missed opportunities to appropriately use TXA but also increased overuse. In addition, TXA administration was an independent risk factor for venous thromboembolism. A reevaluation of the use of TXA in combat casualties should be undertaken.

Noninvasive Multimodal Imaging to Predict Recovery of Locomotion after Extended Limb Ischemia.

Acute limb ischemia is a common cause of morbidity and mortality following trauma both in civilian centers and in combat related injuries. Rapid determination of tissue viability and surgical restoration of blood flow are desirable, but not always possible. We sought to characterize the response to increasing periods of hind limb ischemia in a porcine model such that we could define a period of critical ischemia (the point after which irreversible neuromuscular injury occurs), evaluate non-invasive methods for characterizing that ischemia, and establish a model by which we could predict whether or not the animal’s locomotion would return to baselines levels post-operatively. Ischemia was induced by either application of a pneumatic tourniquet or vessel occlusion (performed by clamping the proximal iliac artery and vein at the level of the inguinal ligament). The limb was monitored for the duration of the procedure with both 3-charge coupled device (3CCD) and infrared (IR) imaging for tissue oxygenation and perfusion, respectively. The experimental arms of this model are effective at inducing histologically evident muscle injury with some evidence of expected secondary organ damage, particularly in animals with longer ischemia times. Noninvasive imaging data shows excellent correlation with post-operative functional outcomes, validating its use as a non-invasive means of viability assessment, and directly monitors post-occlusive reactive hyperemia. A classification model, based on partial-least squares discriminant analysis (PLSDA) of imaging variables only, successfully classified animals as “returned to normal locomotion” or “did not return to normal locomotion” with 87.5% sensitivity and 66.7% specificity after cross-validation. PLSDA models generated from non-imaging data were not as accurate (AUC of 0.53) compared the PLSDA model generated from only imaging data (AUC of 0.76). With some modification, this limb ischemia model could also serve as a means on which to test therapies designed to prolong the time before critical ischemia.

Resuscitative Endovascular Balloon Occlusion of the Aorta: A Bridge to Flight Survival

&NA; Trauma endures as the leading cause of death worldwide, and most deaths occur in the first 24 hours after initial injury as a result of hemorrhage. Historically, about 90% of battlefield deaths occur before the injured person arrives at a theater hospital, and most are due to noncompressible hemorrhage of the torso. Resuscitative endovascular balloon occlusion of the aorta is an evolving technique to quickly place a balloon into the thoracic or abdominal aorta to efficiently block blood flow to distal circulation. Maneuvers, such as resuscitative endovascular balloon occlusion of the aorta, to control endovascular hemorrhage offer a potential intervention to control noncompressible hemorrhage. This technique can be performed percutaneously or open in prehospital environments to restore hemodynamic functions and serve as a survival bridge until the patient is delivered to a treatment facility for definitive surgical hemostasis. This article describes the indications, complications, and application of resuscitative endovascular balloon occlusion of the aorta to military and civilian aeromedical transport. (Critical Care Nurse. 2018;38[2]:69‐75)