A multivariate logistic regression analysis of risk factors for blunt cerebrovascular injury.

INTRODUCTION: The diagnosis of blunt cerebrovascular injuries (BCVI) has improved with widespread adaptation of screening protocols and more accurate multi-detector computed tomography (MDCT-A) angiography. The population at risk and for whom screening is indicated is still controversial. To help determine which blunt trauma patients would best benefit from screening we performed a comprehensive analysis of risk factors associated with BCVI. METHODS: All patients with BCVI from June 12, 2000 (the date at which our institution began screening for these injuries) to June 30, 2009 were identified by the primary author (JDB) and recorded in a prospective database. Associated injuries were identified retrospectively by International Classification of Diseases, Ninth Revision (ICD-9) code and compared with similar patients without BCVI. Demographic information was also compared from data obtained from the trauma registry. Univariate analyses exploring associations between individual risk factors and BCVI were performed using Fisher's exact test for dichotomous variables and Student's t test for continuous variables. Additionally, relative risk (RR) was calculated for dichotomous variables to describe the strength of the relationship between the categorical risk factors and BCVI. Multivariate logistic regression models for BCVI, BCAI (blunt internal carotid artery injury), and BVAI (blunt vertebral artery injury) were developed to explore the relative contributions of the various risk factors. RESULTS: One hundred two patients with BCVI were identified out of 9935 blunt trauma patients admitted during this time period (1.03% incidence). Fifty-nine patients (0.59% incidence) had a BVAI and 43 patients (0.43% incidence) had a BCAI. Univariate analysis found cervical spine fracture (CSI) (RR = 10.4), basilar skull fracture (RR = 3.60), and mandible fracture (RR = 2.51) to be most predictive of the presence of BCVI (P < .005). Independent predictors of BCVI on multivariate logistic regression were CSI (OR = 7.46), mandible fracture (OR = 2.59), basilar skull fracture (OR = 1.76), injury severity score (ISS) (OR = 1.05), and emergency department Glasgow Coma Scale (ED-GCS) (OR = 0.93): all P < .05. CONCLUSIONS: Blunt trauma patients with a high risk mechanism and a low GCS, high injury severity score, mandible fracture, basilar skull fracture, or cervical spine injury are at high risk for BCVI should be screened with MDCT-A.

Early venous thromboembolism prophylaxis with enoxaparin in patients with blunt traumatic brain injury.

OBJECTIVE: To determine the safety of early enoxaparin for venous thromboembolism (VTE) prophylaxis in patients with blunt traumatic brain injury (TBI). METHODS: Prospective observational study of patients with TBI who received enoxaparin within 48 hours after admission. Brain computed tomography (CT) scans were obtained at the time of admission, at 24 hours, and at variable intervals thereafter based on clinical course. Patients were excluded from the study for intracerebral contusions >/=2 cm, multiple contusions within one brain region, subdural or epidural hematomas >/=8 mm, increased size or number of lesions on follow-up CT, persistent intracranial pressure >20 mm Hg, or neurosurgeon or trauma surgeon reluctance to initiate early pharmacologic VTE prophylaxis. Bleeding complications were defined as CT progression of hemorrhage by Marshall CT Classification or radiologists' report, regardless of any neurologic deterioration. Main outcomes measured were intracranial bleeding complications, discharge Glasgow Outcome Score, and hospital mortality. RESULTS: Five hundred twenty-five patients were studied. Eighteen patients (3.4%) had progressive hemorrhagic CT changes after receiving enoxaparin, 12 of whom had no change in treatment, neurologic status, or outcome. Six patients (1.1%) had a change in treatment or potential outcome, including three who required subsequent craniotomy. Twenty-one patients (4.0%) died, and pharmacologic prophylaxis may have contributed to one death (0.2%). Discharge Glasgow Outcome Scores were 445 (84.8%) good recovery, 19 (3.6%) moderate disability, 36 (6.8%) severe disability, 4 (0.8%) persistent vegetative state, and 21 (4.0%) dead. CONCLUSION: Enoxaparin should be considered as an option for early VTE prophylaxis in selected patients with blunt TBI. Early enoxaparin should be strongly considered in those patients with TBI with additional high risk traumatic injuries.

Internal carotid artery stenting for blunt carotid artery injuries with an associated pseudoaneurysm.

BACKGROUND: Blunt carotid artery injuries (BCI) are being recognized and treated with increasing frequency because of improved screening protocols. Recent advances in endovascular techniques using microcoils, angioplasty, and stenting offer a new treatment strategy for those patients with traumatic pseudoaneurysms (PA) (BCI and PA). Experience with these techniques is limited because of the rarity of these injuries. HYPOTHESIS: Early anticoagulation (AC) or antiplatelet (AP) therapy combined with carotid artery stenting is a safe alternative to AC alone for the treatment of grade III carotid artery injuries (BCI and PA). DESIGN: Prospective cohort study. SETTING: A rural, community Level I trauma center. PATIENTS AND METHODS: All patients with a nonocclusive BCI and PA during a 5.5 year period from June 23, 2000 to December 31, 2005 were included in the study. RESULTS: : Eleven patients with grade BCI and PA underwent endovascular repair. Nine patients (81%) had associated traumatic intracranial hemorrhage. AC (heparin drip) or AP therapy (clopidogrel or aspirin or both) was initiated in all patients within 48 hours of diagnosis of BCI. Time from admission to AC or AP was 21 +/- 9.5 hours (mean +/- SD). Mortality rate was 18% (2 of 11). One death was attributed to severe brain injury. The other was attributed to a stroke from the carotid injury. No patient had radiologic progression of traumatic intracranial hemorrhage on head computed tomography despite AP or AC. One patient sustained a mild embolic cerebrovascular ischemic event before stenting. No other survivors developed a stroke or any other evidence of cerebral ischemic symptoms. Two recurrent PAs developed during hospitalization and were successfully managed with an additional stent. All survivors were discharged with a good neurologic outcome. Seven patients had follow-up from 6 months to 4 years: one developed asymptomatic 50% stenosis at 6 months requiring successful angioplasty. All others showed complete healing without stenosis. CONCLUSIONS: Carotid artery stenting is safe and effective initial therapy for patients with nonocclusive BCI and PA. Initial intermediate-term follow-up also fails to demonstrate significant morbidity for up to 4 years.

Off-pump coronary artery bypass is an alternative to conventional cardiopulmonary bypass when repair of traumatic coronary artery injuries is indicated.

Coronary artery injuries after penetrating cardiac trauma are rare. The standard approach to these injuries has traditionally been coronary artery ligation. When cardiac perfusion is profoundly compromised, cardiopulmonary bypass has been used to facilitate revascularization, although with serious morbidity. We report a case of traumatic left anterior descending coronary artery transection repaired off-pump in a young stabbing victim. Penetrating traumatic cardiac injuries are highly lethal injuries. Cardiopulmonary bypass has been used for myocardial revascularization when cardiac perfusion is compromised, although with significant complications. Off-pump coronary artery bypass is a safe alternative in the traumatized patient.

Sixteen-slice multi-detector computed tomographic angiography improves the accuracy of screening for blunt cerebrovascular injury.

BACKGROUND: Blunt cerebrovascular injuries (BCVI) are rare but potentially devastating injuries, particularly if the diagnosis is delayed. Only four-vessel cerebral angiography (FVCA) has been shown to be adequately sensitive and specific as a screening tool for BCVI but is resource-intensive and invasive. Computed tomography (CT) angiography has emerged as a possible alternative, but its accuracy has been poor, particularly for low-grade injuries. Recent advances in CT technology, particularly the use of a multi-detector array for image acquisition should improve the accuracy of this technique. This study is the first reported experience of the role of the 16-slice multi- detector CT scanner in screening for BCVI. METHODS: From January 2, 2003 to October 31, 2004, all patients who met predefined screening criteria were screened for blunt injury to the carotid (BCI) and vertebral (BVI) arteries with a 16-slice multi-detector CT scanner with angiographic reconstruction (CTA). If CTA was positive or equivocal for BCVI, FVCA was performed as a confirmatory test. If CTA was negative, no further diagnostic studies were performed. RESULTS: There were 435 patients who met criteria and were screened with CTA. Of these, 25 injuries were identified in 24 patients for an incidence of BCVI of 1.2% (24/2023) among all blunt admissions (BTA) and 5.5% (24/435) among screened patients (SP). This was increased compared with the four-slice era (0.38% BTA, 2.4% SP, p<0.01). No patient with a negative CTA was subsequently identified as having, or developed neurologic symptoms attributable to a missed BCVI. CONCLUSION: Sixteen-slice multi-detector CT angiography is an excellent tool to screen for BCVI and detects all clinically significant injuries. The detected incidence of BCVI increased more than threefold with the 16-slice scanner when compared with the four-slice scanner. This demonstrates a clear technological improvement in our ability to screen for these injuries.

Extracorporeal support for organ donation after cardiac death effectively expands the donor pool.

BACKGROUND: We sought to evaluate the effect on short-term outcomes of normothermic, extracorporeal perfusion (ECMO) for donation of abdominal organs for transplantation after cardiac death (DCD). Study parameters included increase in number of donors and organs, types of organs procured, and viability of kidneys transplanted. METHODS: We retrospectively reviewed medical record data for all patients enrolled in our ECMO-supported DCD donor protocol between 10/1/2000 to 2/01/2004. We also reviewed the records for all patients undergoing organ donation after brain-death (DBD) during the study period at our institution. Recipient data were obtained and analyzed for all kidneys procured from both groups. RESULTS: Twenty patients were enrolled in our DCD protocol and underwent attempted organ donation. Fifteen patients completed the protocol; 3 maintained cardiac function throughout the prescribed 60 minutes after withdrawal of life support, and two patients' organs were deemed unsuitable for transplantation. Fourteen (70%) of the DCD donor patients originated on the trauma service and six (30%) were from other clinical services. The DCD program increased the potential donor pool by 33% (61 versus 81 patients) and the number of kidneys transplanted by 24% (100 versus 124). A total of 24 kidney, 5 liver, and 1 pancreas transplants were performed with these organs. Two of 24 (8.3%) DCD kidneys had delayed graft function. There were no perioperative rejection episodes or deaths. CONCLUSION: The implementation of a DCD protocol using extracorporeal perfusion increased the potential organ donor pool at our institution by 33%. This was accomplished without short term adverse effect on organ function compared with kidneys transplanted from DBD donors.

Bronchoalveolar lavage in diagnosis of ventilator-associated pneumonia in patients with burns.

Ventilator-associated pneumonia (VAP) remains a major cause of morbidity and mortality for patients with burns. In nonburn populations, bronchoalveolar lavage (BAL) excludes other pathology such as systemic inflammatory response syndrome. We hypothesized that BAL would decrease our false-positive VAP rate. All ventilated patients with burn injury who were admitted to our institution from July 2000 through June 2003 were included. After June 2001, BAL was used to make the diagnosis of VAP, with > or =10(4) organisms considered a positive result. Fifty patients met criteria for VAP, 21 in the pre-BAL period and 29 in the BAL period. Six patients (21%) in the BAL group had quantitative cultures <10(4) and were not treated. The outcomes for these patients were not different than those treated for VAP. There were no differences in age, TBSA size, antibiotic use, or ventilator days for the pre-BAL or BAL groups, although the pneumonia rate was lower for the BAL time period. The use of BAL eliminated the unnecessary antibiotic treatment of 21% of patients in the BAL time period and was associated with a lower rate of VAP.

Pelvic ring fractures: implications of vehicle design, crash type, and occupant characteristics.

BACKGROUND: Pelvic ring fractures (PRFs) are a major cause of morbidity and mortality in motor vehicle collisions (MVCs). Understanding the factors leading to PRFs may help improve vehicle design and safety. This study sought to determine the vehicular, crash, and occupant characteristics that contribute to PRFs. METHODS: From 1997 to 2003, 240 adult patients involved in lateral or frontal crashes were prospectively studied. Comprehensive crash reconstructions, vehicle analysis, and occupant data were compiled and analyzed as part of the national Crash Injury Research Engineering Network project. RESULTS: Of 240 study patients, 38 had PRFs. The incidence of PRFs was significantly associated with female gender, lateral impact crashes, vehicle incompatibility, and severity of crash. Seat belts and airbags were not protective against PRFs in either lateral or frontal crashes. CONCLUSIONS: All vehicles in the current study were less than 6 years old at the time of the MVC and thus reflect newer safety designs. Compared with studies of PRFs in MVCs before the widespread adoption of modern safety standards, our series suggests there has been a modest decrease in the incidence of PRFs in newer vehicles. Current safety standards do not adequately protect against PRFs, especially in lateral MVCs involving incompatibility and female occupants. New technology needs to be developed and implemented. Our data suggest that side impact airbags, alteration of vehicle geometry, and increased reinforcement of side panels and doors may result in fewer PRFs.

Blunt splenic injury: operation versus angiographic embolization.

BACKGROUND: Splenic injuries, like other blunt traumatic injuries, are increasingly treated with non-operative management. Angiographic embolization (AE) has emerged as an alternative modality for treatment of splenic injuries. We hypothesized that splenic embolization would lead to equivalent, if not improved, outcomes in terms of mortality, total costs, complications, and duration of stay. METHODS: A retrospective review of a prospective data set was performed for all adult splenic injuries admitted to our level I trauma center from 2000 through 2003. Demographics, number of red cell units, emergency department hemodynamics, costs, and outcomes were examined. The operative group included those who underwent computed tomography (CT) first then went to the operating room (OR) (CT+OR) or those who went directly to the OR. RESULTS: There were 25 CT+OR and 24 AE patients of 164 blunt splenic injuries. After univariate analysis, higher injury severity score (ISS), lower systolic blood pressure, lower pH, and higher packed red blood cell transfusions were associated with increased mortality and duration of stay. The splenic Abbreviated Injury Scale (AIS; mean +/- SD) was the same for AE compared to CT+OR patients (3.8 +/- 0.4 vs 3.5 +/- 0.9). Although the AE group was older (50 +/- 20 vs 36 +/- 13 years, P < .01), Glasgow Comma Score (13 +/- 4 vs 11 +/- 5), age, highest heart rate (109 +/- 24 vs 120 +/- 43), and splenic AIS were not predictive of the need for an operation. Abdominal complications were lower in the AE group compared to the CT+OR (13% vs 29%), but mortality was not different (8% vs 4%). Total costs were similar for both groups after adjustment for ISS, GCS, pH, pretreatment transfusions, and spleen AIS (AE, $49,300 +/- $40,460 vs CT+OR, $54,590 +/- $34,760). The non-operative failure rate in this study was 2%. CONCLUSIONS: AE of splenic injuries is safe and associated with fewer complications. The spleen AIS, heart rate, age, and GCS did not correlate with the need for an operation. Higher ISS, lower blood pressure, lower pH, and increased number of packed red blood cell transfusions were better indicators of the need for an operation versus embolization.

Extracorporeal life support for severe acute respiratory distress syndrome in adults.

OBJECTIVE: Severe acute respiratory distress syndrome (ARDS) is associated with a high level of mortality. Extracorporeal life support (ECLS) during severe ARDS maintains oxygen and carbon dioxide gas exchange while providing an optimal environment for recovery of pulmonary function. Since 1989, we have used a protocol-driven algorithm for treatment of severe ARDS, which includes the use of ECLS when standard therapy fails. The objective of this study was to evaluate our experience with ECLS in adult patients with severe ARDS with respect to mortality and morbidity. METHODS: We reviewed our complete experience with ELCS in adults from January 1, 1989, through December 31, 2003. Severe ARDS was defined as acute onset pulmonary failure, with bilateral infiltrates on chest x-ray, and PaO2/fraction of inspired oxygen (FiO2) ratio < or =100 or A-aDO2 >600 mm Hg despite maximal ventilator settings. The indication for ECLS was acute severe ARDS unresponsive to optimal conventional treatment. The technique of ECLS included veno-venous or veno-arterial vascular access, lung "rest" at low FiO2 and inspiratory pressure, minimal anticoagulation, and optimization of systemic oxygen delivery. RESULTS: During the study period, ECLS was used for 405 adult patients age 17 or older. Of these 405 patients, 255 were placed on ECLS for severe ARDS refractory to all other treatment. Sixty-seven percent were weaned off ECLS, and 52% survived to hospital discharge. Multivariate logistic regression analysis identified the following pre-ELCS variables as significant independent predictors of survival: (1) age (P = 0.01); (2) gender (P = 0.048); (3) pH < or =7.10 (P = 0.01); (4) PaO2/FiO2 ratio (P = 0.03); and (5) days of mechanical ventilation (P < 0.001). None of the patients who survived required permanent mechanical ventilation or supplemental oxygen therapy. CONCLUSION: Extracorporeal life support for severe ARDS in adults is a successful therapeutic option in those patients who do not respond to conventional mechanical ventilator strategies.

Gender differences in hip anatomy: possible implications for injury tolerance in frontal collisions.

Male occupants in frontal motor vehicle collisions have reduced tolerance for hip fractures than females in similar crashes. We studied 92 adult pelvic CT scans and found significant gender differences in bony pelvic geometry, including acetabular socket depth and femoral head width. Significant differences were also noted in the presentation angle of the acetabular socket to frontal loading. The observed differences provide biomechanical insight into why hip injury tolerance may differ with gender. These findings have implications for the future design of vehicle countermeasures as well as finite element models capable of more accurately predicting body tolerances to injury.

Delayed repair for blunt thoracic aortic injury: is it really equivalent to early repair?

BACKGROUND: Blunt thoracic aortic injury (BTAI) is a severe injury that traditionally has mandated immediate surgical repair. Delaying operative intervention for BTAI can allow other life-threatening injuries to be managed first, but potentially increases the risk of aortic rupture and death. The objective of this study was to evaluate the outcome of delayed repair (DR) compared with early repair (ER) for BTAI and to assess the effectiveness of a protocol for medical control of systolic blood pressure and heart rate in those patients whose repairs were delayed. METHODS: This study is a retrospective review of University of Michigan Health System (UMHS) data from January 1, 1992, through March 1, 2003. ER was defined as operative repair within 16 hours from the time of injury. A similar analysis was conducted for patients with BTAI selected from the National Trauma Data Bank. RESULTS: For the UMHS data, there were 45 patients in the DR group and 33 patients in the ER group. Mortality in the ER group versus the DR group was 9% versus 20%. Multivariate analysis adjusting for age, Injury Severity Score, abdominal Abbreviated Injury Scale score, Glasgow Coma Scale score, and intubation status demonstrated an odds ratio for death from ER compared with DR of 1.72 (p = 0.57). Patients undergoing DR had an absolute increase in hospital length of stay (33.1 vs. 20.9 days) and complication rate (2.1 vs. 1.5 incidents per patient). A similar result was obtained for multivariate analysis of the National Trauma Data Bank data, with an odds ratio of 1.40 (p = 0.51) for death from ER versus DR. UMHS patients whose repairs were delayed achieved target systolic blood pressure and heart rate for 76% and 74% of the hourly measurements recorded, respectively. CONCLUSION: Patients with BTAI can safely undergo delayed aortic repair if other injuries warrant a higher treatment priority without increasing their overall risk of mortality. Delayed repair is, however, associated with a higher complication rate.