Challenging Traditional Paradigms in Posttraumatic Pulmonary Thromboembolism.

Importance: Pulmonary clots are seen frequently on chest computed tomography performed after trauma, but recent studies suggest that pulmonary thrombosis (PT) and pulmonary embolism (PE) after trauma are independent clinical events. Objective: To assess whether posttraumatic PT represents a distinct clinical entity associated with the nature of the injury, different from the traditional venous thromboembolic paradigm of deep venous thrombosis (DVT) and PE. Design, Setting, and Participants: This prospective, observational, multicenter cohort study was conducted by the Consortium of Leaders in the Study of Traumatic Thromboembolism (CLOTT) study group. The study was conducted at 17 US level I trauma centers during a 2-year period (January 1, 2018, to December 31, 2020). Consecutive patients 18 to 40 years of age admitted for a minimum of 48 hours with at least 1 previously defined trauma-associated venous thromboembolism (VTE) risk factor were followed up until discharge or 30 days. Exposures: Investigational imaging, prophylactic measures used, and treatment of clots. Main Outcomes and Measures: The main outcomes of interest were the presence, timing, location, and treatment of any pulmonary clots, as well as the associated injury-related risk factors. Secondary outcomes included DVT. We regarded pulmonary clots with DVT as PE and those without DVT as de novo PT. Results: A total of 7880 patients (mean [SD] age, 29.1 [6.4] years; 5859 [74.4%] male) were studied, 277 with DVT (3.5%), 40 with PE (0.5%), and 117 with PT (1.5%). Shock on admission was present in only 460 patients (6.2%) who had no DVT, PT, or PE but was documented in 11 (27.5%) of those with PE and 30 (25.6%) in those with PT. Risk factors independently associated with PT but not DVT or PE included shock on admission (systolic blood pressure <90 mm Hg) (odds ratio, 2.74; 95% CI, 1.72-4.39; P < .001) and major chest injury with Abbreviated Injury Score of 3 or higher (odds ratio, 1.72; 95% CI, 1.16-2.56; P = .007). Factors associated with the presence of PT on admission included major chest injury (14 patients [50.0%] with or without major chest injury with an Abbreviated Injury Score >3; P = .04) and major venous injury (23 [82.1%] without major venous injury and 5 [17.9%] with major venous injury; P = .02). No deaths were attributed to PT or PE. Conclusions and Relevance: To our knowledge, this CLOTT study is the largest prospective investigation in the world that focuses on posttraumatic PT. The study suggests that most pulmonary clots are not embolic but rather result from inflammation, endothelial injury, and the hypercoagulable state caused by the injury itself.

Delayed Intracranial Hemorrhage in Anticoagulated Geriatric Patients After Ground Level Falls.

BACKGROUND: The reported risk of delayed intracranial hemorrhage (ICH) in a trauma patient on warfarin is estimated to be between 0.6% and 6%. The risk of delayed ICH in trauma patients taking novel oral anticoagulants (NOACs) is not well-defined. OBJECTIVE: We hypothesized that there was a significant number of delayed presentations of ICH in patients on NOACs. METHODS: A retrospective review of our trauma registry was performed on geriatric patients (age older than 64 years) who were initially evaluated at our level I trauma center, had fall from standing height or less, and were anticoagulated (warfarin or NOACs), from April 2017 to March 2018. RESULTS: Seventy-seven patients met inclusion criteria. The mean age was 80 ± 7.7 years and 46% of patients were male. The admission head computed tomography scan was positive in 20.8% of patients. Positive scans were more common in patients on warfarin vs. NOACs (30% vs. 14%; p = 0.074) and had a significantly higher Injury Severity Score (median [interquartile range]: 9 [3-15] vs. 5 [1-9]; p = 0.030) and Abbreviated Injury Scale-Head score (median [interquartile range]: 1 [0-3] vs. 1 [0-2]; p = 0.035). The agreement between loss of consciousness (LOC) and ICH was 72% (κ = -0.064; p = 0.263). Fifty-one percent of patients had a repeat head CT. New ICH was diagnosed in 9.6% of patients. All of these patients were on NOACs. CONCLUSIONS: A fall from standing or less in anticoagulated geriatric patients is a significant mechanism of injury resulting in ICH. The absence of LOC does not eliminate the possibility of ICH. There is a significant risk of delayed ICH for patients on NOACs and repeat evaluations should be performed. A prospective multicenter evaluation of this finding is warranted.

Airway, breathing, computed tomographic scanning: duplicate computed tomographic imaging after transfer to trauma center.

BACKGROUND: Trauma patients imaged at community hospitals often receive duplicate computed tomographic (CT) imaging after transfer to regional trauma centers (RTCs). CT scanning is expensive, is resource intensive, and has acknowledged radiation risk to the patient. The objective of this study was to review and evaluate the frequency, indications, impact on patient management, as well as associated radiation and charges for duplicate CT imaging of trauma patients transferred to our RTC from outside hospitals (OSH). METHODS: Patients transferred to our RTC between September 2009 and August 2010 were evaluated prospectively. The OSH patients' charts and provider interviews were used to determine the reasons for repeated scans. The primary outcome was frequency of duplicate CT scan, defined as a repeated CT image of the same body part within 24 hours. The reason for duplicate imaging and impact on patient management was categorized. Radiation exposure and charges for duplicate scans were also determined. RESULTS: Of the 185 patients transferred to our facility, 177 were eligible. CT examinations at the OSH were performed on 137 patients (77%). A duplicate CT examination occurred in 38 patients (28%). The most common reason for duplicate CT scanning was lack of thin-section multiplanar data, on images sent via CD-ROM (37%). There was a change in management in 16 patients (42%). The patients with duplicate scanning received a median of 10.2 mSv (interquartile range, 6.6-15.7 mSv) of additional radiation, with a median charge of $409 (interquartile range, $307-$734). CONCLUSION: More than one third of duplicated scans performed on transferred trauma patients were potentially avoidable, primary owing to inadequate transfer of data from the OSH CT scan. The capacity of a single CD-ROM is insufficient to contain full imaging data from a trauma scan, and establishing direct links to imaging data from OSHs would decrease the number of repeated CT scans performed on transferred trauma patients. LEVEL OF EVIDENCE: Care management study, level III.

Compliance with the Eastern Association for the Surgery of Trauma guidelines for prophylactic antibiotics after open extremity fracture.

CONTEXT: Prophylactic antibiotics, paired with wound care and surgical intervention, is considered the standard of care for patients with open fracture. Guidelines from the Eastern Association for the Surgery of Trauma (EAST) recommend specific prophylactic antimicrobial therapy based on the type of open fracture. AIMS: We quantified adherence to EAST guideline recommendations and documented the incidence of infection in patients with open fracture. SETTINGS AND DESIGN: A retrospective, observational study of all patients with open fracture admitted to our facility from January 2004 to December 2008 was conducted. MATERIALS AND METHODS: Patients were divided into compliant and noncompliant groups according to the EAST guideline recommendations. Compliance was defined as an appropriate spectrum of therapy for guideline suggested duration. We assessed for surgical and non-surgical site infections, and morbidity outcomes. STATISTICAL ANALYSIS: Nominal data were explored using summary measures. Continuous variables were compared using the Student t-test or the Mann-Whitney U-test. Dichotomous data were compared using χ(2) statistic or Fisher's exact test. RESULTS: The final analysis included 214 patients. Prophylactic antibiotics were guideline compliant in 28.5% of patients, and ranged from 10.0% in type 3b fractures to 52.7% in type 1 fractures. The most common reason for non-compliance was the use of guideline recommended coverage that exceeded the suggested duration (71.2%). Patients who received non-compliant therapy required prolonged hospital lengths of stay (6 vs. 3 days, P = 0.0001). The overall incidence of infection was similar regardless of guideline compliance (17.0% vs. 11.5%, P = 0.313). CONCLUSIONS: Prophylactic antibiotics for open fracture frequently exceeded guideline recommendations in duration and spectrum of coverage, especially in more severe fracture types. Non-compliance with EAST recommendations was associated with increased in-hospital morbidity.

Telemedicine to a moving ambulance improves outcome after trauma in simulated patients.

BACKGROUND: Rural trauma victims often require prolonged transport by s with limited scopes of practice. We evaluated the impact of telemedicine (TM) to a moving ambulance on outcomes in simulated trauma patients. METHODS: This is an institutional review board approved, prospective double-blind study. Three trauma scenarios (blunt torso trauma, epigastric stab wound, and closed head injury) were created for a human patient simulator. Intermediate emergency medical technicians (EMTs; n = 20) managed the human patient simulator, in a moving ambulance. In the TM group, physicians (n = 12) provided consultation. In the non-TM group, EMTs communicated with medical control by radio, as necessary. We tabulated the fraction of 13 key signs, 5 pathologic processes, and 12 key interventions that were performed. Vital signs and Sao2 (%) were recorded. Data were compared using the Wilcoxon rank-sum test. RESULTS: Lowest Sao2 (84 ± 0.7 vs. 78 ± 0), lowest systolic blood pressure (70 ± 1 vs. 53 ± 1), and highest heart rate (144 ± 0.9 vs. 159 ± 0.5) were significantly improved in the TM group (p < 0.001). Recognition rates for key signs (0.96 ± 0.01 vs. 0.79 ± 0.05), processes (0.98 ± 0.02 vs. 0.75 ± 0.05), and critical interventions (0.92 ± 0.02 vs. 0.49 ± 0.03) were higher in the TM group (p < 0.003). EMTs were successfully guided through needle decompression procedures in 22 of 24 cases (zero in the non-TM group). CONCLUSION: TM to a moving ambulance improved the care of simulated trauma patients. Furthermore, procedurally naïve EMTs were able to perform needle thoracostomy and pericardiocentesis with TM guidance.

Utility of ampicillin-sulbactam for empiric treatment of ventilator-associated pneumonia in a trauma population.

BACKGROUND: Ampicillin-sulbactam is guideline-recommended treatment for early-onset ventilator-associated pneumonia (VAP). However, intensive care unit clinicians are encountering increasing resistance to ampicillin-sulbactam. We sought to analyze the time period for early-onset VAP in our trauma population by using daily evaluation of resistance to ampicillin-sulbactam. METHODS: A retrospective cohort study was completed on all mechanically ventilated trauma patients admitted to a rural level-1 trauma center from January 2003 to December 2008 who were diagnosed with VAP. Daily bacterial resistance to ampicillin-sulbactam > 15% was defined as the threshold for early empiric antibiotic failure for the first episode of VAP. A univariate analysis of risk factors for multi-drug resistant pathogens (MDRPs) and comorbidities was completed to assess for predisposing factors for ampicillin-sulbactam resistance. RESULTS: One hundred sixty-three pathogens were identified in 121 trauma patients diagnosed with VAP. Of these isolates, 71% were gram-negative, 28% were gram-positive, and 1% was fungal. Methicillin-susceptible Staphylococcus aureus (23.9%), H aemophilus influenzae (20.9%), and Pseudomonas aeruginosa (11.7%) were the most common infecting organisms. Daily ampicillin-sulbactam resistance was 40%, 26%, 32%, 43%, 50%, and 60% on days 3 to 7 and ≥ 8 days, respectively. Only the presence of MDRP risk factors (89% vs. 65%, p < 0.01) and hospital LOS (36.8 [22.8-49.0] vs. 25.7 days [19.0-32.5], p < 0.01) was different between ampicillin- sulbactam resistant and ampicillin-sulbactam susceptible VAP groups. On univariate analysis, hospital length of stay >4 days and antibiotic use within 90 days were associated with ampicillin-sulbactam resistant VAP (p < 0.01). CONCLUSIONS: Ampicillin-sulbactam is not an effective empiric therapy for early-onset VAP in our rural trauma population. The utility of ampicillin-sulbactam should be reviewed at other institutions to assess for appropriate empiricism.

Management of the most severely injured spleen: a multicenter study of the Research Consortium of New England Centers for Trauma (ReCONECT).

OBJECTIVE: To determine the rate and predictors of failure of nonoperative management (NOM) in grade IV and V blunt splenic injuries (BSI). DESIGN: Retrospective case series. SETTING: Fourteen trauma centers in New England. PATIENTS: A total of 388 adult patients with a grade IV or V BSI who were admitted between January 1, 2001, and August 31, 2008. MAIN OUTCOME MEASURES: Failure of NOM (f-NOM). RESULTS: A total of 164 patients (42%) were operated on immediately. Of the remaining 224 who were offered a trial of NOM, the treatment failed in 85 patients (38%). At the end, 64% of patients required surgery. Multivariate analysis identified 2 independent predictors of f-NOM: grade V BSI and the presence of a brain injury. The likelihood of f-NOM was 32% if no predictor was present, 56% if 1 was present, and 100% if both were present. The mortality of patients for whom NOM failed was almost 7-fold higher than those with successful NOM (4.7% vs 0.7%; P = .07). CONCLUSIONS: Nearly two-thirds of patients with grade IV or V BSI require surgery. A grade V BSI and brain injury predict failure of NOM. This data must be taken into account when generalizations are made about the overall high success rates of NOM, which do not represent severe BSI.

Frequency of inappropriate continuation of acid suppressive therapy after discharge in patients who began therapy in the surgical intensive care unit.

STUDY OBJECTIVE: To determine the frequency with which patients who begin to receive stress ulcer prophylaxis in the surgical intensive care unit (SICU) are discharged receiving inappropriate acid suppressive therapy (AST). DESIGN: Prospective, observational evaluation. Setting. Level 1 trauma center and academic tertiary care hospital. PATIENTS: A total of 248 consecutive adult patients admitted to the SICU during a 6-month period who began to receive AST with a proton pump inhibitor or histamine(2)-receptor antagonist. MEASUREMENTS AND MAIN RESULTS: In most patients (237 [95.6%] of 248), initiation of AST was associated with one or more risk factors for gastrointestinal bleeding. Continuation of AST during hospitalization outside the SICU occurred in 215 patients (86.7%). Sixty patients (24.2%) were discharged from the hospital receiving AST: 52 patients (21.0%) went to skilled nursing facilities or rehabilitation centers, and eight (3.2%) were discharged home. Compared with those whose AST was discontinued in the hospital, patients who continued to receive AST after hospital discharge required extended mechanical ventilation (p=0.001), had twice as many risk factors for gastrointestinal bleeding (p<0.001), were frequently discharged with anticoagulant therapy (p<0.001), exhibited longer hospital and SICU stays (p<0.001), and more frequently demonstrated Glasgow Coma Scale scores of 8 or lower and/or had head injury (p<0.001), hepatic failure (p=0.004), and major trauma (p=0.049). Evaluation of continuation of AST during hospitalization revealed that only 7.4% (16/215) of patients at SICU transfer and 5.0% (3/60) of patients at hospital discharge had a compelling risk factor to continue AST as demonstrated by a coagulopathy at discharge; no patients required mechanical ventilation at hospital discharge. CONCLUSION: Most patients inappropriately continued to receive stress ulcer prophylaxis during post-SICU hospitalization. Presence of risk factors for stress ulcer-related gastrointestinal bleeding at SICU admission appears to influence continuation of AST after discharge from the hospital. A low percentage (3.2%) of patients was discharged home receiving inappropriate AST, yet overall, few study patients demonstrated a compelling risk factor for continuation of AST.

Evaluation of feeding intolerance in patients with pentobarbital-induced coma.

BACKGROUND: There is considerable debate regarding the appropriateness of feeding patients by the enteral route in conjunction with pentobarbital coma therapy. OBJECTIVE: To determine the incidence of feeding intolerance (FI) in patients receiving pentobarbital in conjunction with enteral nutrition (EN). METHODS: A retrospective, observational evaluation of patients (>14 y of age) who received a therapeutic pentobarbital coma in combination with EN was conducted. Patients were divided into groups, based on the occurrence of FI defined as aspiration of gastric residuals greater than 75 mL for 2 consecutive measurements. RESULTS: Forty-eight percent (29 of 61) of patients experienced FI based on our definition. The median pentobarbital infusion rate did not differ significantly between patients who experienced FI versus those who did not (median [intraquartile range, IQR] 1.8 mg/kg/h [1.4, 2.1] vs 1.7 mg/kg/h [1.4, 2.5]; p = 0.680). The total pentobarbital bolus dose during the first 24 hours of therapy was lower in patients who experienced FI (700 mg [225, 980] vs 1000 mg [600, 1475]; p = 0.029). Median duration of pentobarbital therapy was comparable between groups (141.0 h [93.3, 217.3] vs 116.3 h [64.0, 174.8]; p = 0.115). Other factors with the potential to influence FI, such as catecholamines, neuromuscular blockade, and hyperglycemia, were similar between groups. The higher narcotic doses and greater percentage of patients receiving benzodiazepines in the FI group warrants further study. CONCLUSIONS: Pentobarbital therapy did not preclude use of EN in the entire study population. In addition, FI did not occur at a greater frequency in patients who received a higher dosage, a longer duration, or an earlier initiation of pentobarbital therapy.

Oxygen saturation determined from deep muscle, not thenar tissue, is an early indicator of central hypovolemia in humans.

OBJECTIVE: To compare the responses of noninvasively measured tissue oxygen saturation (StO2) and calculated muscle oxygen tension (PmO2) to standard hemodynamic variables for early detection of imminent hemodynamic instability during progressive central hypovolemia in humans. DESIGN: Prospective study. SETTING: Research laboratory. SUBJECTS: Sixteen healthy human volunteers. INTERVENTIONS: Progressive lower body negative pressure (LBNP) to onset of cardiovascular collapse. MEASUREMENTS AND MAIN RESULTS: Noninvasive measurements of blood pressures, heart rate, and stroke volume were obtained during progressive LBNP with simultaneous assessments of StO2, PmO2, and muscle oxygen saturation (SmO2). Forearm SmO2 and PmO2 were determined with a novel near infrared spectroscopic measurement device (UMMS) and compared with thenar StO2 measured by a commercial device (HT). All values were normalized to the duration of LBNP exposure required for cardiovascular collapse in each subject (i.e., LBNP maximum). Stroke volume was significantly decreased at 25% of LBNP maximum, whereas blood pressure was a late indicator of imminent cardiovascular collapse. PmO2 (UMMS) was significantly decreased at 50% of maximum LBNP while SmO2 (UMMS) decreased at 75% of maximum LBNP. Thenar StO2 (HT) showed no statistical change throughout the entire LBNP protocol. CONCLUSIONS: Spectroscopic assessment of forearm muscle PO2 and SmO2 provides noninvasive and continuous measures that are early indicators of impending cardiovascular collapse resulting from progressive reductions in central blood volume.

Can near-infrared spectroscopy identify the severity of shock in trauma patients?

BACKGROUND: Our recent experimental study showed that peripheral muscle tissue oxygen saturation (StO2), determined noninvasively by near-infrared spectroscopy (NIRS), was more reliable than systemic hemodynamics or invasive oxygenation variables as an index of traumatic shock. The purpose of this study was to establish the normal range of thenar muscle StO2 in humans and the relationship between shock state and StO2 in trauma patients. METHODS: This was a prospective, nonrandomized, observational, descriptive study in normal human volunteers (n = 707) and patients admitted to the resuscitation area of our Level I trauma center (n = 150). To establish a normal StO2 range, an NIRS probe was applied to the thenar eminence of volunteers (normals). Subsequently, in a group of trauma patients, an NIRS probe was applied to the thenar eminence and data were collected and stored for offline analysis. StO2 monitoring was performed continuously and noninvasively, and values were recorded at 2-minute intervals. Five moribund trauma patients were excluded. Members of our trauma faculty, blinded to StO2 values, classified each patient into one of four groups (no shock, mild shock, moderate shock, and severe shock) using conventional physiologic parameters. RESULTS: Mean +/- SD thenar StO2 values for each group were as follows: normals, 87 +/- 6% (n = 707); no shock, 83 +/- 10% (n = 85); mild shock, 83 +/- 10% (n = 19); moderate shock, 80 +/- 12% (n = 14); and severe shock, 45 +/- 26% (n = 14). The thenar StO2 values clearly discriminated the normals or no shock patients and the patients with severe shock (p < 0.05). CONCLUSION: Decreased thenar muscle tissue oxygen saturation reflects the presence of severe hypoperfusion and near-infrared spectroscopy may be a novel method for rapidly and noninvasively assessing changes in tissue dysoxia.

Building a better fluid for emergency resuscitation of traumatic brain injury.

UNLABELLED: Hextend (HEX) is a colloid solution that is FDA-approved for volume expansion during surgery. ATL-146e is a novel adenosine A2A receptor agonist that has anti-inflammatory, neuroprotective, and coronary vasodilator properties. Three series of experiments were designed to evaluate the therapeutic potential of HEX+/-ATL-146e for emergency resuscitation from traumatic brain injury (TBI) + hemorrhagic hypotension. METHODS: In the first two studies in vivo, anesthetized, ventilated pigs (30-45 kg) received a fluid percussion TBI, 45% arterial hemorrhage, and 30 minutes shock period. In Series 1, resuscitation consisted of unlimited crystalloid (n = 8) or HEX (n = 8) to correct systolic arterial pressure >100 mm Hg and heart rate <100 bpm for the first 60 minutes ("emergency phase"), and then maintain cerebral perfusion pressure (CPP) > 70 mm Hg for 60-240 minutes. In Series 2 (n = 31), resuscitation consisted of a 1 L bolus of HEX + ATL-146e (10 ng/kg/min, n = 10) or HEX +placebo (n = 10) followed by crystalloid to the same endpoints. In Series 3 in vivo, the hemodynamic response evoked by 0, 10, 50, or 100 ng/kg/min ATL-146e was measured before or 60 minutes after HEX resuscitation from 45% hemorrhage. RESULTS: Following TBI+hemorrhage, there were 4/22 deaths in series 1 and 11/31 deaths in series 2. In those alive at 30 minutes, mean arterial pressure, cardiac index, mixed venous O2 saturation, and cerebral venous O2 saturation were all reduced by 40-60%, while heart rate and lactate were increased 2-5 fold. With no resuscitation (n = 2), there was minimal hemodynamic compensation and progressive acidosis. Upon resuscitation, these values corrected but intracranial pressure progressively rose from <5 mm Hg to 15-20 mm Hg. Series 1: With HEX (n = 8) versus crystalloid (n = 8), CPP was less labile, acid/base was maintained, and the fluid requirement was reduced by 60% (all p < 0.05) Series 2: With ATL-146e (n = 10) versus placebo (n = 10), stroke volume and cardiac output were improved by 40-60%, and the fluid requirement was reduced by 30% (all p < 0.05). Series 3: ATL-146e caused a dose-related increase (p < 0.05) in stroke volume after, but not before, hemorrhage. The effects on pre-load, afterload, and heart rate were similar before and after hemorrhage. CONCLUSIONS: HEX alone is a safe and efficacious low volume alternative to initial crystalloid resuscitation after TBI. An adenosine A2A agonist combined with 1 L of HEX safely and effectively counteracted a decrease in cardiac performance noted after TBI+hemorrhage without causing hypotension or bradycardia.

Noninvasive muscle oxygenation to guide fluid resuscitation after traumatic shock.

BACKGROUND: Three different protocols tested the hypothesis that hind limb muscle tissue O(2) saturation (StO(2)), measured noninvasively with near-infrared spectroscopy (NIRS), is as reliable as invasive systemic oxygenation indices to guide fluid resuscitation. METHODS: In series 1, swine (n=30) were hemorrhaged, then received either no fluid, a fixed volume of colloid (15 mL/kg), or shed blood plus lactated Ringer's (LR) titrated to MAP >60 mm Hg. In series 2, swine (n=16) received a penetrating femur injury, a 47% to 55% hemorrhage to determine a median lethal dose (LD(50)) then shed blood plus LR titrated to MAP >60 mm Hg. In series 3, swine (n=5) received the femur injury plus LD(50) hemorrhage, and were resuscitated with LR titrated to StO(2) >50%. RESULTS: In series 1, StO(2) tracked mixed venous O(2) saturation (SvO(2)), but discriminated between 3 survivor groups better than SvO(2), arterial lactate, or arterial base excess. In series 2, StO(2) tracked SvO(2) but discriminated between 2 survivor groups better than SvO(2), arterial lactate, or arterial base excess. In series 3, animals survived to extubation when resuscitated to an StO(2) target. CONCLUSIONS: Noninvasive muscle StO(2) determined by NIRS was more reliable than invasive oxygenation variables as an index of shock. Because muscle StO(2) can be easily monitored in emergency situations, it may represent an improved method to gauge the severity of shock or the adequacy of fluid resuscitation after trauma.