Diane Morabito

Thromboembolism after trauma: an analysis of 1602 episodes from the American College of Surgeons National Trauma Data Bank

Objective:Venous thromboembolic events (VTE) are potentially preventable causes of morbidity and mortality after injury. We hypothesized that the current clinical incidence of VTE is relatively low and that VTE risk factors could be identified. Methods:We queried the ACS National Trauma Data Bank for episodes of deep venous thrombosis (DVT) and/or pulmonary embolism (PE). We examined demographic data, VTE risk factors, outcomes, and VTE prophylaxis measures in patients admitted to the 131 contributing trauma centers. Results:From a total of 450,375 patients, 1602 (0.36%) had a VTE (998 DVT, 522 PE, 82 both), for an incidence of 0.36%. Ninety percent of patients with VTE had 1 of the 9 risk factors commonly associated with VTE. Six risk factors found to be independently significant in multivariate logistic regression for VTE were age ≥40 years (odds ratio [OR] 2.01; 95% confidence interval [CI] 1.74 to 2.32), lower extremity fracture with AIS ≥3 (OR 1.92; 95% CI 1.64 to 2.26), head injury with AIS ≥3 (OR 1.24; 95% CI 1.05 to 1.46), ventilator days >3 (OR 8.08; 95% CI 6.86 to 9.52), venous injury (OR 3.56; 95% CI 2.22 to 5.72), and a major operative procedure (OR 1.53; 95% CI 1.30 to 1.80). Vena cava filters were placed in 3,883 patients, 86% as PE prophylaxis, including in 410 patients without an identifiable risk factor for VTE. Conclusions:Patients who need VTE prophylaxis after trauma can be identified based on risk factors. The use of prophylactic vena cava filters should be re-examined.

Use of Low Molecular Weight Heparin in Preventing Thromboembolism in Trauma Patients

OBJECTIVE To investigate the safety and effectiveness of low molecular weight heparin (LMWH) in preventing deep venous thrombosis (DVT) in high-risk trauma patients, compared with mechanical methods of prophylaxis. DESIGN A prospective randomized trial conducted over a 19-month period in an urban, academic trauma center. METHODS All trauma patients with the following risk factors for the development of DVT were considered for enrollment in this study: any injury with an Abbreviated Injury Scale score > or = 3; major head injury (Glasgow Coma Scale score < or = 8); spine, pelvic, or lower extremity fractures; acute venous injury; or age > 50 years. After a screening venous duplex examination, the patients were assigned to a Heparin versus No-Heparin group, depending upon the presence of injuries precluding the use of heparin. In the Heparin group, the patients were then randomized to receive either LMWH or optimal mechanical compression (defined as bilateral sequential gradient pneumatic compression (SCD) or, in the presence of lower extremity injuries precluding the use of the SCD, the arteriovenous impulse (AVI) compression system). All the patients in the No-Heparin group received optimal compression. Enrolled patients underwent sequential duplex examinations every 5 to 7 days until discharge. RESULTS Of the 487 consecutive patients initially enrolled in this study, 372 were available for at least the first two duplex examinations and comprise the study population. Only nine (2.4%) patients developed DVT, compared with the predicted 9.1% rate in high-risk trauma patients receiving no prophylaxis (p = 0.037). Of the 120 patients who were randomized to receive LMWH, only one (0.8%) developed DVT. In the SCD group, there were 5 of 199 patients (2.5%) with DVT, and 3 of 53 (5.7%) in the AVI group. One patient with DVT also had clinical symptoms of pulmonary embolism, but there were no deaths secondary to pulmonary embolism. There was one major bleeding complication potentially associated with the use of LMWH. CONCLUSIONS The administration of LMWH is a safe and extremely effective method of preventing DVT in high-risk trauma patients. When heparin is contraindicated, aggressive attempts at mechanical compression are warranted.

The effect of age on functional outcome in mild traumatic brain injury: 6-month report of a prospective multicenter trial

OBJECTIVE Elderly patients (aged 60 years and older) have been demonstrated to have an increased mortality after isolated traumatic brain injury (TBI); however, the prognosis of those patients surviving their hospitalization is unknown. We hypothesized that surviving elderly patients would also have decreased functional outcome, and this study examined the functional outcome of patients with isolated TBI at discharge and at 6 months posthospitalization. METHODS This was a multicenter prospective study of all patients with isolated moderate to severe TBI defined as Head Abbreviated Injury Scale score of 3 with an Abbreviated Injury Scale score in any other body area of 1. Patients surviving to discharge gave their consent and were enrolled. Data collected included demographics, Glasgow Coma Scale (GCS) score at admission, and neurosurgical interventions. Outcome data included discharge disposition and Glasgow Outcome Scale score and modified Functional Independence Measure (FIM) score at discharge and at 6 months. RESULTS Two hundred thirty-five patients were enrolled, with 44 (19%) aged greater than or equal to 65 years. Mechanisms of injury were falls (34%), assaults (28%), motor vehicle collisions (14%), pedestrian (11%), and other (12%). Falls were more common in the older patients and assaults in the younger group. The mean admitting GCS score was 12.8 (95% confidence interval [CI], 12.4-13.3), with older patients having a higher mean GCS score, 14.1 (95% CI, 13.6-14.6) versus 12.5 (95% CI, 12.0-13.1; p = 0.03). There were no differences in the percentage of patients admitted to the intensive care unit or requiring neurosurgical intervention between younger and older patients. Because there were few elderly patients with low GCS scores who survived to discharge, outcome measures focused on those patients with GCS scores of 13 to 15. A greater percentage of elderly were discharged to rehabilitation (28% vs. 16%, p =0.08). The mean discharge FIM score was 10.4 (95% CI, 9.8-11.0) for the elderly versus 11.4 (95% CI, 11.1-11.7) for the young (p =0.001), with 68% elderly and 89% young discharged with total independent scores of 11 to 12. At 6 months, the difference narrowed, but the mean FIM score was still greater for the young group, 11.7 (95% CI, 11.6-11.9) versus 11.0 (95% CI, 10.6-11.4; p < 0.001). CONCLUSION Functional outcome after isolated mild TBI as measured by the Glasgow Outcome Scale and modified FIM is generally good to excellent for both elderly and younger patients. Older patients required more inpatient rehabilitation and lagged behind their younger counterparts but continued to recover and improve after discharge. Although there were statistically significant differences in the FIM score at both discharge and 6 months, the clinical importance of these small differences in the mean FIM score to the patients quality of life is less clear. Measurable improvement in functional status during the first 6 months after injury is observed in both groups. Aggressive management and care of older patients with TBI is warranted, and efforts should be made to decrease inpatient mortality. Continued follow-up is ongoing to determine whether these outcomes persist at 12 months.

the Development of Acute Lung Injury Is Associated with Worse Neurologic Outcome in Patients with Severe Traumatic Brain Injury

OBJECTIVE The purpose of this study was to determine the incidence of acute lung injury (ALI) in trauma patients with severe traumatic brain injury (TBI), to evaluate the impact of ALI on mortality and neurologic outcome after severe traumatic brain injury (TBI), and to identify whether the development of ALI correlates with the severity of TBI. METHODS Clinical data were collected prospectively over a 4-year period in a Level I trauma center. Patients included in the study met the following criteria: mechanical ventilation > 24 hours, head Abbreviated Injury Scale score >or= 3, no other body region Abbreviated Injury Scale score >or= 3, and age between 18 and 54 years. ALI was defined using international consensus criteria. Glasgow Outcome Scale scores were assessed at 3 and 12 months. Bivariate comparisons were made between ALI and non-ALI groups. Multivariate analysis with stepwise logistical regression was used to assess independent factors on mortality. The patients admission head computed tomographic (CT) scan was graded using the Marshall system, and the presence and size of specific intracranial abnormality was noted. Glasgow Coma Scale (GCS) score, Marshall CT scan score, and intracranial abnormality were correlated with the development of ALI. RESULTS One hundred thirty-seven patients with isolated head trauma were enrolled in the study over a 4-year period. Thirty-one percent of patients with severe TBI developed ALI. Head trauma patients with ALI had a significantly higher ISS, a greater number of days on the ventilator, and a worse neurologic outcome for those who survived their hospitalization. Mortality was 38% in the ALI group and 15% in the non-ALI group (p = 0.004). Only 3 of 16 (19%) of the deaths within the ALI group were directly related to ALI. By multivariate analysis, only the presence of ALI, older age, and lower initial GCS score were associated with higher mortality. There was no association between ISS, the presence of arterial hypotension (arterial systolic pressure < 90 mm Hg) at admission to the hospital, or the amount of blood transfused and mortality. No correlation was found between the severity of head injury (GCS score, Marshall score, or intracranial abnormality) and development of ALI. CONCLUSION The development of ALI is a critical independent factor affecting mortality in patients suffering traumatic brain injury and is associated with a worse long-term neurologic outcome in survivors. The risk of developing ALI is not associated with specific anatomic lesions diagnosed by cranial CT scanning.

Brain tissue oxygen tension is more indicative of oxygen diffusion than oxygen delivery and metabolism in patients with traumatic brain injury

Objectives:Despite the growing clinical use of brain tissue oxygen monitoring, the specific determinants of low brain tissue oxygen tension (Pbto2) following severe traumatic brain injury (TBI) remain poorly defined. The objective of this study was to evaluate whether Pbto2 more closely reflects variables related to cerebral oxygen diffusion or reflects cerebral oxygen delivery and metabolism. Design:Prospective observational study. Setting:Level I trauma center. Patients:Fourteen TBI patients with advanced neuromonitoring underwent an oxygen challenge (increase in Fio2 to 1.0) to assess tissue oxygen reactivity, pressure challenge (increase in mean arterial pressure) to assess autoregulation, and CO2 challenge (hyperventilation) to assess cerebral vasoreactivity. Interventions:None. Measurements and Main Results:Pbto2 was measured directly with a parenchymal probe in the least-injured hemisphere. Local cerebral blood flow (CBF) was measured with a parenchymal thermal diffusion probe. Cerebral venous blood gases were drawn from a jugular bulb venous catheter. We performed 119 measurements of Pao2, arterial oxygen content (Cao2), jugular bulb venous oxygen tension (P&OV0413;o2), venous oxygen content (C&OV0413;o2), arteriovenous oxygen content difference (AVDO2), and local cerebral metabolic rate of oxygen (locCMRO2). In multivariable analysis adjusting for various variables of cerebral oxygen delivery and metabolism, the only statistically significant relationship was that between Pbto2 and the product of CBF and cerebral arteriovenous oxygen tension difference (AVTO2), suggesting a strong association between brain tissue oxygen tension and diffusion of dissolved plasma oxygen across the blood-brain barrier. Conclusions:Measurements of Pbto2 represent the product of CBF and the cerebral AVTO2 rather than a direct measurement of total oxygen delivery or cerebral oxygen metabolism. This improved understanding of the cerebral physiology of Pbto2 should enhance the clinical utility of brain tissue oxygen monitoring in patients with TBI.

Serum levels of Hsp 72 measured early after trauma correlate with survival.

BACKGROUND Experimental studies have shown that hemorrhagic shock is associated with the expression of inducible heat proteins, especially heat shock protein (Hsp) 72, in liver, brain, heart, and kidney. Moreover, induction of Hsp 72 by various stressors before the onset of shock has been associated with the attenuation of organ injury caused by hemorrhage. However, it is not known whether Hsp 72 is expressed after severe trauma in humans. The purpose of this study was therefore to determine whether Hsp 72 could be detected in the serum of patients early after severe trauma and whether serum levels of Hsp 72 might correlate with survival of trauma patients or the severity of the postinjury inflammatory response. METHODS Clinical data were collected prospectively over a 3-year period for trauma patients mechanically ventilated for more than 2 days who met the following inclusion criteria: Injury Severity Score > or = 16, and age > 18 years. Physiologic data for quantitative assessment of organ dysfunction were collected for each patient. Hsp 72 and nitrate and nitrite levels were measured in the serum of trauma patients collected at or 12 to 48 hours after the admission to the emergency department. RESULTS Sixty-seven patients with severe trauma were enrolled in the study. Hsp 72 was detected in the serum of all trauma patients. All patients with high initial serum levels of Hsp 72 (serum levels > 15 ng/mL) survived, whereas 29% of the patients with low Hsp 72 serum levels died from their traumatic injuries (p = 0.01). The overall mortality was 21%, occurring within 5 to 7 days. Patients who died were older (mean age, 54 +/- 15 years) than those who survived (mean age, 36 +/- 15 years) (p < 0.0.05). The cause of death was attributable to head injury in 79%, although the severity of head injury (Abbreviated Injury Scale score) was not statistically different between survivors with high serum values of Hsp 72 and patients who died. There was no correlation between the initial serum Hsp 72 values and the severity of organ dysfunction or clinical indicators of the inflammatory response. CONCLUSION Hsp 72 can be detected in the serum of severely traumatized patients within 30 minutes after injury. Elevated initial serum levels of Hsp 72 (serum levels > 15 ng/mL) are associated with survival after severe trauma, but are not related to the incidence or severity of the postinjury inflammatory response or organ dysfunction.

Trauma assessment training with a patient simulator: a prospective, randomized study.

BACKGROUND Patient simulators are computer-controlled mannequins that may increase realism during trauma training by providing real-time changes in vital signs and physical findings during trauma scenarios. We hypothesized that trauma assessment training on a patient simulator would be as effective as training with a more traditional moulage patient/actor. METHODS This study was conducted during a surgery intern orientation at two academic trauma centers. Interns (n = 60) attended a basic trauma course, and were then randomized to trauma assessment practice sessions with either the patient simulator (n = 30) or a moulage patient (n = 30). After practice sessions, interns were randomized a second time to an individual trauma assessment test on either the simulator or the moulage patient. Two surgeon-judges rated each intern live and on video for completion of 50 predetermined assessment objectives (total score) divided into sections (primary and secondary survey, general performance, diagnostic studies/procedures, and plan) and the identification and management of an acute neurologic deterioration in the test patient (event score). Multiple linear regression with random student effects was used to estimate the independent effects of all study variables. RESULTS Within randomized groups, mean trauma assessment test scores for all simulator-trained interns were higher when compared with all moulage-trained interns (71 +/- 8 vs. 66 +/- 8, respectively; p = 0.02). Simulator training independently showed a small but statistically significant improvement in both the total score and the event score (+4.6 and +8.6, respectively; p < 0.05). CONCLUSION Use of a patient simulator to introduce trauma assessment training is feasible and compares favorably to training in a moulage setting. Continued research in this area of physician education is warranted.

Transforming Research and Clinical Knowledge in Traumatic Brain Injury Pilot: Multicenter Implementation of the Common Data Elements for Traumatic Brain Injury

Traumatic brain injury (TBI) is among the leading causes of death and disability worldwide, with enormous negative social and economic impacts. The heterogeneity of TBI combined with the lack of precise outcome measures have been central to the discouraging results from clinical trials. Current approaches to the characterization of disease severity and outcome have not changed in more than three decades. This prospective multicenter observational pilot study aimed to validate the feasibility of implementing the TBI Common Data Elements (TBI-CDEs). A total of 650 subjects who underwent computed tomography (CT) scans in the emergency department within 24 h of injury were enrolled at three level I trauma centers and one rehabilitation center. The TBI-CDE components collected included: 1) demographic, social and clinical data; 2) biospecimens from blood drawn for genetic and proteomic biomarker analyses; 3) neuroimaging studies at 2 weeks using 3T magnetic resonance imaging (MRI); and 4) outcome assessments at 3 and 6 months. We describe how the infrastructure was established for building data repositories for clinical data, plasma biomarkers, genetics, neuroimaging, and multidimensional outcome measures to create a high quality and accessible information commons for TBI research. Risk factors for poor follow-up, TBI-CDE limitations, and implementation strategies are described. Having demonstrated the feasibility of implementing the TBI-CDEs through successful recruitment and multidimensional data collection, we aim to expand to additional study sites. Furthermore, interested researchers will be provided early access to the Transforming Research and Clinical Knowledge in TBI (TRACK-TBI) data set for collaborative opportunities to more precisely characterize TBI and improve the design of future clinical treatment trials. (ClinicalTrials.gov Identifier NCT01565551.).

Carbon dioxide reactivity and pressure autoregulation of brain tissue oxygen.

OBJECTIVETo describe the normal relationships between brain tissue oxygen tension (PbrO2) and physiological parameters of systemic blood pressure and CO2 concentrations. METHODSLicox Clark-type oxygen probes (GMS mbH, Kiel, Germany) were inserted in the frontal white matter of 12 swine maintained under general anesthesia with a 1.0 fraction of inspired oxygen (FiO2). In seven swine, alterations in end-tidal carbon dioxide (ET-CO2) concentration (range, 13–72 mm Hg) were induced via hyperventilation or instillation of CO2 into the ventilation circuit. In nine swine, mean arterial pressure (MAP) (range, 33–200 mm Hg) was altered; phenylephrine was used to induce hypertension, and a nitroprusside-esmolol combination or systemic hemorrhage was used for hypotension. Quantitative cerebral blood flow (CBF) was measured in two animals by using a thermal diffusion probe. RESULTSMean baseline PbrO2 was 41.9 ± 11.3 mm Hg. PbrO2 varied linearly with changes in ET-CO2, ranging from 20 to 60 mm Hg (r2 = 0.70). The minimum PbrO2 with hypocarbia was 5.9 mm Hg, and the maximum PbrO2 with hypercarbia was 132.4 mm Hg. PbrO2 varied with MAP in a sigmoid fashion suggestive of pressure autoregulation between 60 and 150 mm Hg (r2 = 0.72). The minimum PbrO2 with hypotension was 1.4 mm Hg, and the maximum PbrO2 with hypertension was 97.2 mm Hg. In addition, CBF correlated linearly with PbrO2 during CO2 reactivity testing (r2 = 0.84). CONCLUSIONIn the uninjured brain, PbrO2 exhibits CO2 reactivity and pressure autoregulation. The relationship of PbrO2 with ET-CO2 and MAP appears to be similar to those historically established for CBF with ET-CO2 and MAP. This suggests that, under normal conditions, PbrO2 is strongly influenced by factors that regulate CBF.

Diffusion Tensor Imaging for Outcome Prediction in Mild Traumatic Brain Injury: A TRACK-TBI Study

We evaluated 3T diffusion tensor imaging (DTI) for white matter injury in 76 adult mild traumatic brain injury (mTBI) patients at the semiacute stage (11.2±3.3 days), employing both whole-brain voxel-wise and region-of-interest (ROI) approaches. The subgroup of 32 patients with any traumatic intracranial lesion on either day-of-injury computed tomography (CT) or semiacute magnetic resonance imaging (MRI) demonstrated reduced fractional anisotropy (FA) in numerous white matter tracts, compared to 50 control subjects. In contrast, 44 CT/MRI-negative mTBI patients demonstrated no significant difference in any DTI parameter, compared to controls. To determine the clinical relevance of DTI, we evaluated correlations between 3- and 6-month outcome and imaging, demographic/socioeconomic, and clinical predictors. Statistically significant univariable predictors of 3-month Glasgow Outcome Scale-Extended (GOS-E) included MRI evidence for contusion (odds ratio [OR] 4.9 per unit decrease in GOS-E; p=0.01), ≥1 ROI with severely reduced FA (OR, 3.9; p=0.005), neuropsychiatric history (OR, 3.3; p=0.02), age (OR, 1.07/year; p=0.002), and years of education (OR, 0.79/year; p=0.01). Significant predictors of 6-month GOS-E included ≥1 ROI with severely reduced FA (OR, 2.7; p=0.048), neuropsychiatric history (OR, 3.7; p=0.01), and years of education (OR, 0.82/year; p=0.03). For the subset of 37 patients lacking neuropsychiatric and substance abuse history, MRI surpassed all other predictors for both 3- and 6-month outcome prediction. This is the first study to compare DTI in individual mTBI patients to conventional imaging, clinical, and demographic/socioeconomic characteristics for outcome prediction. DTI demonstrated utility in an inclusive group of patients with heterogeneous backgrounds, as well as in a subset of patients without neuropsychiatric or substance abuse history.