Venous thromboembolism after trauma: a never event?*.

OBJECTIVE: Rates of venous thromboembolism as high as 58% have been reported after trauma, but there is no widely accepted screening protocol. If Medicare adds venous thromboembolism to the list of "preventable complications," they will no longer reimburse for treatment, which could have devastating effects on many urban centers. We hypothesized that prescreening with a risk assessment profile followed by routine surveillance with venous duplex ultrasound that could identify asymptomatic venous thromboembolism in trauma patients. DESIGN: Prospective, observational trial with waiver of consent. SETTING: Level I trauma center intensive care unit. PATIENTS: At admission, 534 patients were prescreened with a risk assessment profile. INTERVENTIONS: Patients (n = 106) with risk assessment profile scores >10 were considered high risk and received routine screening venous duplex ultrasound within 24 hrs and weekly thereafter. RESULTS: In prescreened high-risk patients, 20 asymptomatic deep vein thrombosis were detected with venous duplex ultrasound (19%). An additional ten venous thromboembolisms occurred, including six symptomatic deep vein thrombosis and four pulmonary emboli, resulting in an overall venous thromboembolism rate of 28%. The most common risk factors discriminating venous thromboembolism vs. no venous thromboembolism were femoral central venous catheter (23% vs. 8%), operative intervention >2 hrs (77% vs. 46%), complex lower extremity fracture (53% vs. 32%), and pelvic fracture (70% vs. 47%), respectively (all p < .05). Risk assessment profile scores were higher in patients with venous thromboembolism (19 ± 6 vs. 14 ± 4, p = .001). Risk assessment profile score (odds ratio 1.14) and the combination of pelvic fracture requiring operative intervention >2 hrs (odds ratio 5.75) were independent predictors for development of venous thromboembolism. The rates of venous thromboembolism for no chemical prophylaxis (33%), unfractionated heparin (29%), dalteparin (40%), or inferior vena cava filters (20%) were not statistically different (p = .764). CONCLUSIONS: Medicare's inclusion of venous thromboembolism after trauma as a "never event" should be questioned. In trauma patients, high-risk assessment profile score and pelvic fracture with prolonged operative intervention are independent predictors for venous thromboembolism development, despite thromboprophylaxis. Although routine venous duplex ultrasound screening may not be cost-effective for all trauma patients, prescreening using risk assessment profile yielded a cohort of patients with a high prevalence of venous thromboembolism. In such high-risk patients, routine venous duplex ultrasound and/or more aggressive prophylactic regimens may be beneficial.

The Role of Thromboelastography in Identifying Coagulopathy Among Geriatric Traumatic Brain Injury Patients.

Background The geriatric population has the highest incidence of head injury, and those who are anticoagulated have an increased risk of traumatic intracranial hemorrhage (ICH). The availability of viscoelastic coagulation studies has coincided with the development of many anticoagulation reversal agents. In this study, our objective was to assess whether the thromboelastography (TEG) assay affected clinical decision-making regarding reversal agent administration among geriatric patients with ICH caused by blunt head trauma. Methodology We prospectively screened adults aged 65 and older with head trauma presenting to the emergency departments of two level-one trauma centers. International Classification of Diseases, Tenth Revision codes S00-09 were used to identify the diagnosis of head injury. Patients with CT head imaging positive for acute ICH were included. Each patient was assessed for home use of antiplatelet or anticoagulant medications, as well as in-hospital use of any reversal agents. Reversal agent administration and mortality were compared between patients who received TEG and those who did not. Results A total of 680 patients had acute ICH on head CT, and 324 (48%) patients received TEG. More patients screened with TEG were transfused platelets (30.2% vs. 10.7%, p < 0.001). This remained significant for patients taking anticoagulants, antiplatelets, or neither. There were no differences in the administration of other reversal agents (prothrombin complex concentrate or fresh frozen plasma) or mortality whether or not TEG was performed. Conclusions Patients who had TEG performed were more likely to receive platelet reversal agents, regardless of antiplatelet medication usage. Among elderly adults with ICH, TEG is a rapid screening test that may help identify patients with platelet function abnormalities requiring reversal.

Novel prehospital monitor with injury acuity alarm to identify trauma patients who require lifesaving intervention.

BACKGROUND: A miniature wireless vital signs monitor (MWVSM, www.athena.gtx.com) has been designed according to US Special Operations Command specifications for field monitoring of combat casualties. It incorporates an injury acuity algorithm termed the Murphy Factor (MF), which is calculated from whatever vital signs are available at the moment and changes in the last 30 seconds. We tested the hypothesis that MF can identify civilian trauma patients during prehospital transport who will require a lifesaving intervention (LSI) upon hospital admission. METHODS: From December 2011 to June 2013, a prospective trial was conducted in collaboration with prehospital providers. The MWVSM detects skin temperature, pulse oximetry (SpO2), heart rate (HR), pulse wave transit time, and MF. LSIs included: intubation, tube thoracostomy, central line insertion, blood product transfusion, and operative intervention. Prehospital MWVSM data were compared with simultaneous vital signs (SaO2, systolic blood pressure (SBP), and HR) from a conventional vital signs monitor. Sensitivity, specificity, negative predictive value, positive predictive value, and area under the receiving operating characteristic curves were calculated. RESULTS: Ninety-six trauma patients experienced predominantly blunt trauma (n = 80, 84%), were mostly male (n = 79, 82%), and had a mean ± SD age of 48 ± 19 years and an Injury Severity Score (ISS) of 10 (17). Those who received an LSI (n = 48) had similar demographics but higher ISS (18 vs. 5) and mortality (23% vs. 0%) (all p < 0.05). The most common LSIs were intubation (n = 24, 25%), blood product transfusion (n = 19, 20%), and emergency surgery (n = 19, 20%). Compared with HR > 100 beats/min, SBP < 90 mm Hg, SaO2 < 95% alone or in combination, MF > 3 during the entire transport time had the largest area under the receiving operating characteristic curves (0.620, p = 0.081). MF greater than 3 had a specificity of 81%, sensitivity of 39%, positive predictive value of 68%, and negative predictive value of 57% for the need for LSI. CONCLUSION: A single numeric value has the potential to summarize overall patient status and identify prehospital trauma patients who need an LSI. Prehospital monitoring combined with algorithms that include trends over time could improve prehospital care for both civilian and military trauma. LEVEL OF EVIDENCE: Prospective observational, level II.

Hypercoagulability and other risk factors in trauma intensive care unit patients with venous thromboembolism.

BACKGROUND: Thromboelastography (TEG) on hospital admission can identify hypercoagulable trauma patients at risk for venous thromboembolism (VTE), but the value of TEGs obtained after multiple interventions, including tranexamic acid (TXA), has not been defined. We test the following hypotheses. (1) TEG on intensive care unit (ICU) admission can help stratify patients screened with Greenfield's risk assessment profile (RAP) for VTE. (2) TXA is a VTE risk factor, and its effect on fibrinolysis can be identified with TEG. METHODS: Trauma patients who survived to the ICU with RAP ≥ 10 received serial venous duplex ultrasound examinations and blood samples for coagulation analysis at admission to the ICU and weekly thereafter. RESULTS: Six hundred seventy-eight patients were screened and 121 were enrolled; 76% blunt injury, Injury Severity Score (ISS) 27, 13% mortality. Thromboprophylaxis was administered to 90% of the patients and was started a median of 2 days after hospital admission. VTE was detected in 28% (n = 34) of the patients (27 deep vein thrombosis and 7 pulmonary emboli) and occurred a median 10 days after admission. Twenty-nine percent (n = 10) of VTE occurred within 2 days of admission. Most variables were similar between those with and without VTE, but the VTE group received more operations (3 (2) vs. 2 (2), p = 0.044), had increased ICU days (25 (34) days vs. 15 (18) days, p = 0.004), and was more likely to have abdominal injury with Abbreviated Injury Scale (AIS) score > 2 (59% vs. 39%, p = 0.050). Upon ICU admission, standard coagulation markers were within normal limits, while TEG demonstrated hypercoagulability, but neither was associated with VTE. Repeat TEG one week after admission (n = 58) remained hypercoagulable but transitioned to a different pattern with increased clot strength. TXA was associated with reduced fibrinolysis on initial TEG (p < 0.05) but was not associated with VTE. CONCLUSION: Trauma ICU patients with RAP ≥ 10 are hypercoagulable at admission to ICU and remain so during recovery. They have a ≥ 25% rate of VTE, despite thromboprophylaxis. TXA is associated with reduced fibrinolysis but does not increase VTE rates. Neither TEG nor standard coagulation markers (measured on ICU admission) stratify high-risk patients who develop VTE from those who do not. LEVEL OF EVIDENCE: Prognostic study, level III.

Vasopressor use during emergency trauma surgery.

Most evidence suggests early vasopressor use is associated with death after trauma, but no previous study has focused on patients requiring emergency operative intervention (OR). We test the hypothesis that vasopressors are harmful in this population. Records from 746 patients requiring OR from July 2009 to March 2013 were retrospectively reviewed and stratified based on vasopressor use (epinephrine [EPI], phenylephrine, ephedrine, norepinephrine, dobutamine, vasopressin) or no vasopressor use. Vasopressors were administered to 225 patients (30%) during OR; 59 patients (8%) received multiple vasopressors. Patients who received vasopressors were older, more severely injured, had worse vital signs, and increased mortality rate (all P < 0.001). EPI was independently associated with mortality (odds ratio, 6.88; P = 0.001). If patients who received EPI were excluded, there was no difference in mortality between those who received vasopressors alone or in combination and those that did not (5 vs 6%, P = 0.523), although multiple markers of injury severity were worse. We conclude that vasopressor use is relatively common in the most severely injured patients requiring OR and is associated with mortality. EPI is most often used for cardiac arrest, whereas other vasopressors are used for their vasoconstrictive properties. This suggests that, except for EPI, vasopressors during OR are not independently associated with mortality.

Admission hematocrit and transfusion requirements after trauma.

BACKGROUND: The decision to transfuse packed RBCs (PRBC) during initial resuscitation of trauma patients is based on physiologic state, evidence for blood loss, and potential for ongoing hemorrhage. Initial hematocrit (Hct) is not considered an accurate marker of blood loss. This study tests the hypothesis that admission Hct is associated with transfusion requirements after trauma. METHODS: From June to December 2008, data from 1,492 consecutive admissions at a Level I trauma center were retrospectively reviewed to determine whether initial Hct was associated with PRBC transfusions. From October 2009 through October 2011, data from 463 consecutive transfused patients were retrospectively reviewed to determine whether Hct correlated with number of PRBC units received. RESULTS: Packed RBC transfusion was not correlated with heart rate and was more highly correlated with Hct (r = -0.45) than with systolic blood pressure or base deficit (r = -0.32 or r = -0.26). Hematocrit was a better overall predictor than systolic blood pressure (sensitivity 45% vs 29%, specificity 94% vs 98%, area under receiver operator characteristic curve 0.71 vs 0.64). Lower Hct was associated with hypotension, more advanced shock, higher blood loss, and increased transfusion of PRBC, plasma, platelets, or cryoprecipitate (all, p < 0.01). CONCLUSION: Admission Hct is more strongly associated with the PRBC transfusion than either tachycardia, hypotension, or acidosis. Admission Hct is also correlated with 24-hour blood product requirements in those receiving early transfusions. These findings challenge current thinking and suggest that fluid shifts are rapid after trauma and that Hct can be important in initial trauma assessment.

Hypercoagulability after burn injury.

BACKGROUND: Hypercoagulability is a homeostatic response to trauma, but relatively little information is available about coagulation changes after burn injury. Therefore, we tested the hypothesis that burn patients are hypercoagulable at admission and/or during recovery. METHODS: A prospective observational trial was conducted at an American Burn Association verified Burn Center. Thromboelastography (TEG) was performed on blood drawn from indwelling catheters upon admission and weekly for those who remained hospitalized. Routine and special coagulation tests were performed on stored samples. Data are expressed as median (interquartile range). RESULTS: Twenty-four patients (88% male) were enrolled, with a median age of 49 (20) years and a median total body surface area burn of 29% (23%); 21 experienced thermal burns (4 inhalational injuries), and 3 had electrical burns. There were no significant differences in TEG or coagulation assays between patients with thermal versus electrical burn injury, but there were significant differences between men versus women and between those with or without inhalational injury. Sixteen patients had repeat samples 1 week after intensive care unit admission. The repeat TEG was more hypercoagulable (all p < 0.05). Fibrinogen and natural anticoagulation proteins (protein C, protein S, and antithrombin III) were also increased (all p < 0.05). Two patients (8%) developed venous thromboembolism (VTE); TEG reaction time, fibrinogen, and partial thromboplastin time were decreased (all p < 0.05) at admission compared with those with no VTE. All changes occurred despite pharmacologic thromboprophylaxis. There was no significant correlation between TEG and total body surface area or between TEG and fluid balance. CONCLUSION: In general, burn patients have normal coagulation parameters at admission but become hypercoagulable during recovery. However, those who are hypercoagulable at admission may have an increased risk of VTE. Additional monitoring and/or thromboprophylaxis may be indicated. LEVEL OF EVIDENCE: Epidemiologic/prognostic study, level III.

Repeat head computed tomography after minimal brain injury identifies the need for craniotomy in the absence of neurologic change.

BACKGROUND: In this era of cost containment, the value of routine repeat head computed tomography (CT) in patients with mild TBI (mTBI) and no interval neurologic change has been challenged. The purpose of this study was to test the hypothesis that routine repeat head CT provides critical information after mTBI even with no neurologic change. METHODS: From January 1996 to May 2010, records from all patients admitted to our Level I trauma center with an arrival Glasgow Coma Scale (GCS) score of 13 to 15 and at least one head CT were retrospectively reviewed. RESULTS: In 360 patients with mTBI and positive initial head CT finding, the most common abnormalities were subarachnoid hemorrhage (64%), intraparenchymal hemorrhage (57%), and subdural hemorrhage (40%). Scans were repeated in 8 ± 6 hours; 11% were recalled, 59% remained stable, but 30% showed injury progression. Those patients with worsening repeat head CT finding had higher Injury Severity Score (ISS), were more likely to be intubated and require craniotomy, had longer stay, and had higher mortality (all p < 0.001). On multiple logistic regression, altered GCS score (odds ratio, 3.1-4.0), ISS (odds ratio, 1.1), and presence of mass effect (odds ratio, 2.0) were independently associated with worsening repeat head CT finding. In patients receiving a neurosurgical operative intervention, 32% to 59% had no clinical decline before the worsening repeat CT finding. CONCLUSION: After mTBI, worsening of repeat head CT finding is seen in a third of patients and is associated with worse outcomes. A substantial fraction of patients who require operative intervention will have no clinical changes in the first 8 hours, supporting the value of repeat head CT within this time frame. LEVEL OF EVIDENCE: Care management study, level III.

Vasopressin for cerebral perfusion pressure management in patients with severe traumatic brain injury: preliminary results of a randomized controlled trial.

BACKGROUND: After traumatic brain injury (TBI), catecholamines (CAs) may be needed to maintain adequate cerebral perfusion pressure (CPP), but there are no recommended alternative vasopressor therapies. This is an interim report of the first study to test the hypothesis that arginine vasopressin (AVP) is a safe and effective alternative to CAs for the management of CPP in patients with severe TBI. METHODS: Since 2008, all TBI patients requiring intracranial pressure monitoring at this Level 1 trauma center have been eligible for a randomized trial to receive either CA or AVP if vasopressors were required to maintain CPP greater than 60 mm Hg. RESULTS: To date, 96 patients have been consented and randomized. Demographics, vital signs, and laboratory values were similar. As treated, 60 required no vasopressors and were the least severely injured group with the best outcomes. Twenty-three patients received CA (70% levophed, 22% dopamine, 9% phenylephrine) and 12 patients received AVP. The two vasopressor groups had similar demographics, but Injury Severity Score (ISS) and fluid requirements on intensive care unit Day 1 were worse in the AVP versus the CA groups (all p < 0.05) before treatment. These differences indicate more severe injury with accompanying hemodynamic instability. Nevertheless, adverse events were not increased with AVP versus CA. Trends favored AVP versus CA, but no apparent differences were statistically significant at this interim point. There was no difference in mortality rates between CA and AVP. CONCLUSION: These preliminary results suggest that AVP is a safe and effective alternative to CA for the management of CPP after TBI and support the continued investigation and use of AVP when vasopressors are required for CPP management in TBI patients. LEVEL OF EVIDENCE: Therapeutic study, level II.