Steven R. Shackford

Mercy Medical Center, Мейсон-Сити, Iowa, United States

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Publications (313)820 Total impact

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    ABSTRACT: Background: Current prophylaxis does not completely prevent deep vein thrombosis (DVT) in trauma patients. Recent data suggest that platelets may be a major contributor to hypercoagulability after trauma, indicating a potential role for antiplatelet medications in prophylaxis for DVT. We sought to determine if pre-injury aspirin use was associated with a reduced incidence of lower extremity DVT in trauma patients. Methods: Utilizing a retrospective case-control design, we matched 110 cases of post-trauma lower extremity DVT one-to-one with controls using seven covariates: age, admission date, probability of death, number of DVT risk factors, sex, mechanism of injury, and presence of head injury. Data collected included 26 risk factors for DVT, prehospital medications, and in-hospital prophylaxis. Logistic regression models were created to examine the relationship between pre-hospital aspirin use and post-trauma DVT. Results: Pre-injury aspirin was used by 7.3% of cases (patients diagnosed with in-hospital DVT) compared to 13.6% of controls (p = 0.1). Aspirin was associated with a significant protective effect in multivariate analysis, with an odds ratio of 0.17 (95% confidence interval, 0.04-0.68; p = 0.012) in the most complete model. When stratified by other antithrombotic use, aspirin showed a significant effect only when used in combination with heparinoid prophylaxis (odds ratio 0.35, 95% confidence interval 0.13-0.93, p = 0.036). Conclusion: Pre-injury aspirin use appears to significantly lower DVT rate following injury. This association is strongest when heparinoid prophylaxis is prescribed after patients on pre-injury aspirin therapy are admitted. Aspirin as added prophylaxis for DVT in trauma patients needs to be further evaluated. Level of evidence: Level III; Prognostic and Epidemiological Study.
    No preview · Article · Jan 2016 · Journal of Trauma and Acute Care Surgery
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    ABSTRACT: Background: Studies have shown improved survival after traumatic brain injury with the administration of sympatholytics, including beta-blockers and clonidine, which is thought to attenuate the cardiovascular stress response. However, the use of sympatholytics has not been studied in patients with isolated-severe TBI (ISTBI). We hypothesized that ISTBI patients receiving sympatholytics who demonstrated a reduction in cardiovascular stress would have improved outcomes compared to similarly-injured patients without these cardiovascular changes. Methods: We reviewed the medical records of 338 ISTBI patients (head AIS>3 and associated injury AIS<1) admitted to a Level I trauma center from 2010 through 2014. All patients were managed according to Brain Trauma Foundation guidelines. Demographic, clinical, and survival probability data were gathered. The primary outcome was inpatient mortality. Cardiovascular stress was assessed using the rate-pressure product (RPP=SBP x HR/100) calculated both before and after sympatholytic administration. Associations between independent variables and mortality were adjusted for total hospital length of stay. Results: Among ISTBI patients, observed mortality was 6% (n=20) while predicted mortality by TRISS was 11% (n=38). Administration of sympatholytics was associated with reduction in RPP in univariate analysis (p=0.035). After adjusting for length of stay, neither receipt of beta-blockers nor reduction in RPP was associated with survival. Mean reduction in RPP among survivors was not different from that among nonsurvivors (-4.0% vs. -11.9%, p=0.148). In addition, RPP reduction among patients who received sympatholytics occurred at the same rate in survivors as nonsurvivors (67% vs 68%, p=0.894). Severity of head injury, intraventricular hemorrhage, and any intracranial operative intervention were significantly associated with mortality. Conclusions: Although sympatholytic administration is associated with a significant decrease in RPP, the survival benefit seen in multiply injured patients with traumatic brain injury is not observed among ISTBI patients. Further research on the role of sympatholysis in the management of ISTBI is warranted. Level of evidence: Level III; Therapeutic study.
    No preview · Article · Dec 2015
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    ABSTRACT: Research comparing enoxaparin with unfractionated heparin (UFH) given every 12 hours for venous thromboembolism (VTE) prophylaxis after trauma overlooks original recommendations that UFH be given every 8 hours. We conducted a prospective, randomized, noninferiority trial comparing UFH every 8 hours and standard enoxaparin every 12 hours. We hypothesized that the incidence of VTE in trauma patients receiving UFH every 8 hours would be no more than 10% higher than that in patients receiving enoxaparin every 12 hours. Trauma patients who met criteria for VTE prophylaxis at a Level I trauma center were randomly assigned to 5,000-U UFH every 8 hours or 30-mg enoxaparin every 12 hours between November 2012 and September 2014. Surveillance duplex ultrasound was performed twice weekly on intensive care unit patients and weekly on ward patients. Primary end points were deep vein thrombosis diagnosed by duplex ultrasound and pulmonary embolism diagnosed by computed tomography angiography. Of 495 randomized patients, 220 received UFH and 216 received enoxaparin for analysis. Overall, 105 in the UFH group and 103 in the enoxaparin group underwent VTE surveillance or diagnostic testing. In the analysis of randomized patients who received treatment, UFH was noninferior compared with enoxaparin (absolute VTE risk difference, 3.1%; 95% confidence interval, -1.6% to 7.7%; p = 0.196); however, in the screening ultrasound group, the noninferiority of UFH was inconclusive (absolute VTE risk difference, 6.5%; 95% confidence interval, -2.9% to 15.8%; p = 0.179). The two treatments did not differ with regard to adverse events. The pharmaceutical cost for the regimen of UFH ($2,809) was nearly 20-fold lower than that for enoxaparin ($54,138). A regimen of UFH every 8 hours may be noninferior to enoxaparin every 12 hours for the prevention of VTE following trauma. Given UFH's cost advantage, the use of UFH for VTE prophylaxis may offer greater value. Therapeutic/care management study, level II.
    No preview · Article · Aug 2015
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    ABSTRACT: Venous thromboembolism (VTE) risk assessment models exist to stratify patients at risk for VTE and guide surveillance and prophylaxis. We evaluated the only two models developed specifically for trauma patients: the Trauma Embolic Scoring System (TESS) and the Risk Assessment Profile (RAP). Clinical and demographic data on patients admitted from July 2006 to December 2011 who underwent surveillance lower extremity duplex ultrasound were recorded. Patients were excluded if they were missing one or more of the variables required to calculate either TESS or RAP. Patients received prophylaxis according to American College of Chest Physicians guidelines. TESS and RAP scores were calculated retrospectively and compared between patients with VTE and patients without VTE. High risk was defined by the models as TESS score of 7 or greater and RAP score of 5 or greater. A total of 2,868 patients received surveillance lower extremity duplex ultrasound. TESS score was calculated for 2,140 patients; 215 developed VTE, 110 (51%) of whom had TESS score less than 7. The sensitivity and specificity at a cutoff point of 7 were 49% and 72%, respectively. RAP score was calculated for 1,505 patients; 152 developed VTE, 26 (17%) of whom had RAP score of less than 5. The sensitivity and specificity at a cutoff point of 5 were 83% and 37%, respectively. The area under the receiver operating characteristic curve for each model was 0.66. A clinically significant number of patients who developed VTE were classified as low risk by both TESS and RAP. The indications for VTE surveillance and chemoprophylaxis should not be based exclusively on these scores. These results suggest that additional variables should be sought to improve risk assessment for VTE following trauma. Care management study, level III.
    No preview · Article · Aug 2015

  • No preview · Article · Jun 2015 · Journal of Trauma and Acute Care Surgery
  • Ali Salim · Krista Kaups · Steven R. Shackford · Rosemary Kozar · David Spain · Laura N. Godat

    No preview · Article · Mar 2015 · Journal of Trauma and Acute Care Surgery
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    ABSTRACT: Resuscitation with blood products improves survival in patients with traumatic hemorrhage. However, the risk of venous thromboembolic (VTE) complications associated with fresh frozen plasma (FFP) resuscitation is unknown. We hypothesized that a higher ratio of FFP to packed red blood cells (PRBCs) given during acute resuscitation increases the risk of VTE independent of severity of injury and shock. The records of patients admitted from April 2007 to December 2011 who had surveillance lower extremity duplex ultrasounds were retrospectively reviewed. Patients who received at least 1 U of PRBCs within 24 hours of admission were included. Patients who died without VTE were excluded. The relationship between FFP and VTE was evaluated using logistic regression. A total of 381 patients met inclusion criteria, of whom 77 (20.2%) developed VTE. In patients who required less than 4 U of PRBCs, increasing units of FFP were associated with an increasing risk for VTE, with each unit of FFP having an adjusted odds ratio of 1.27 (95% confidence interval, 1.04-1.54, p = 0.015). Conversely, in patients who required four or greater units of PRBCs, FFP in equal or greater ratios than PRBCs was not associated with VTE. Each unit of FFP increased VTE risk by 25% in patients who required less than 4 U of PRBCs. In patients who required 4 U or greater PRBCs, FFP administration conferred no increased risk of VTE. This suggests that FFP should be used cautiously when early hemodynamic stability can be achieved with less than 4 U of PRBCs. Care management study, level III.
    No preview · Article · Jan 2015 · Journal of Trauma and Acute Care Surgery
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    ABSTRACT: Older patients with traumatic brain injury (TBI) may be at high risk of death after hospitalization. The purpose of this study was to characterize long-term mortality of older TBI patients who survived to discharge. We hypothesized that predictors of postdischarge mortality differed from those of inpatient mortality.
    No preview · Article · Sep 2014 · Journal of Trauma and Acute Care Surgery
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    ABSTRACT: BACKGROUND: The prevention of venous thromboembolic disease following trauma is a priority. In contrast to above-knee deep vein thrombosis (AKDVT), the management of below-knee deep vein thrombosis (BKDVT) is controversial because the risk of pulmonary embolism (PE) has not been firmly established. We hypothesized that BKDVT and AKDVT have an equivalent risk for PE in trauma patients. METHODS: We identified patients from July 2006 to December 2011 with BKDVT and/or AKDVT diagnosed by lower extremity duplex ultrasound (LEDU) and patients with PE diagnosed by computed tomography angiogram. Time of DVT onset, progression or regression, and time of PE were assessed. The BKDVT and AKDVT patient groups were defined by the location of DVT on initial LEDU. The use of therapeutic anticoagulation and inferior vena cava filter (IVCF) were compared between the BKDVT and AKDVT groups. RESULTS: Of 11,330 patients evaluated during the study period, 2,881 (25.4%) underwent surveillance LEDU, and 251 (8.7%) of these patients had DVT alone or associated with PE. BKDVT progressed to AKDVT and/or PE in 21 patients (12.9%). PE rates were 6.1% and 1.1% in the BKDVT and AKDVT groups, respectively (p = 0.1). There was a higher rate of therapeutic anticoagulation and/or IVCF in the AKDVT group than in the BKDVT group (86% vs. 24%, p < 0.0001). CONCLUSION: In our study population, BKDVT was associated with a higher rate of PE compared with AKDVT, which was likely secondary to the treatment of AKDVT. Because BKDVT progressed to AKDVT or PE in 1 of 8 patients, BKDVT should not be ignored in trauma patients. Aggressive chemical prophylaxis and perhaps therapeutic anticoagulation or IVCF should be considered in patients with BKDVT. Further investigation is warranted to confirm these conclusions. (Copyright (C) 2014 by Lippincott Williams & Wilkins)
    No preview · Article · Sep 2014 · Journal of Trauma and Acute Care Surgery
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    ABSTRACT: Traumatic brain injury (TBI) is considered an independent risk factor of venous thromboembolism (VTE). However, the role of TBI severity in VTE risk has not been determined. We hypothesized that increased severity of brain injury in patients with isolated TBI (iTBI) is associated with an increased incidence of VTE.
    No preview · Article · Aug 2014 · Journal of Trauma and Acute Care Surgery

  • No preview · Article · May 2014
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    ABSTRACT: Pulmonary embolus (PE) is thought to arise from a deep venous thrombosis (DVT). Recent data suggest that PE can present without DVT, inferring that PE can originate de novo (DNPE). We examined the relationship between DVT and PE in trauma patients screened for DVT with duplex sonography (DS). We sought to validate the incidence of PE without evidence of DVT and to examine the clinical significance of this entity. We reviewed the medical records of all trauma patients from July 2006 to December 2011 with PE who also had serial surveillance DS (groin to ankle). Demographics, severity of injury, interventions, signs and symptoms of PE, as well as chest computerized tomography findings were collected. Patients with no DS evidence of DVT either before or within 48 hours of PE diagnosis (DNPE) were compared with those with DVT (PE + DVT). Of 11,330 patients evaluated by the trauma service, 2,881 patients received at least one DS. PE occurred in 31 of these patients (1.08%): 19 (61%) were DNPE, and 12 (39%) were PE + DVT. Compared with patients with PE + DVT, patients with DNPE were significantly younger and had more rib fractures, pulmonary contusions, infections, pulmonary symptoms, and peripherally located PEs on computerized tomography. This is the first report of the clinical course of DNPE without embolic origin in a population with comprehensive duplex surveillance. In our series, DNPE seems to be more prevalent after trauma, to be clinically distinct from PE following DVT, and to likely represent a local response to injury or inflammation; however, further research is warranted to fully understand the pathophysiology of DNPE. Care management study, level III.
    No preview · Article · May 2014
  • Steven R. Shackford · Matthew J. Wall · Randall Friese · Carole Y. Villamaria

    No preview · Article · Apr 2014 · Journal of Trauma and Acute Care Surgery
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    ABSTRACT: Anticoagulants and prescription antiplatelet (ACAP) agents widely used by older adults have the potential to adversely affect traumatic brain injury (TBI) outcomes. We hypothesized that TBI patients on preinjury ACAP agents would have worse outcomes than non-ACAP patients. This was a 5.5-year retrospective review of patients 55 years and older admitted to a Level I trauma center with blunt force TBI. Patients were categorized as ACAP (warfarin, clopidogrel, dipyridamole/aspirin, enoxaparin, subcutaneous heparin, or multiple agents) or non-ACAP. ACAP patients were further stratified by class of agent (anticoagulant or antiplatelet). Initial and subsequent head computerized tomographic results were examined for type and progression of TBI. Patient preadmission living status and discharge destination were identified. Primary outcome was in-hospital mortality. Secondary outcomes were progression of initial TBI, development of new intracranial hemorrhage (remote from initial), and the need for an increased level of care at discharge. A total of 353 patients met inclusion criteria: 273 non-ACAP (77%) and 80 ACAP (23%). Upon exclusion of three patients taking a combination of agents, 350 were available for advanced analyses. ACAP status was significantly related to in-hospital mortality. After adjustment for patient and injury characteristics, anticoagulant users were more likely than non-ACAP patients to show progression of initial hemorrhage and develop a new hemorrhagic focus. However, compared with non-ACAP users, antiplatelet users were more likely to die in the hospital. Among survivors to discharge, anticoagulant users were more likely to be discharged to a care facility, but this finding was not robust to adjustment. Older TBI patients on preinjury ACAP agents experience a comparatively higher rate of inpatient mortality and other adverse outcomes caused by the effects of antiplatelet agents. Our findings should inform decision making regarding prognosis and caution against grouping anticoagulant and antiplatelet users together in considering outcomes. Therapeutic study, level IV.
    Full-text · Article · Feb 2014
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    ABSTRACT: Gunshot wounds and blast injuries to the face (GSWBIFs) produce complex wounds requiring management by multiple surgical specialties. Previous work is limited to single institution reports with little information on processes of care or outcome. We sought to determine those factors associated with hospital complications and mortality. We performed an 11-year multicenter retrospective cohort analysis of patients sustaining GSWBIF. The face, defined as the area anterior to the external auditory meatuses from the top of the forehead to the chin, was categorized into three zones: I, the chin to the base of the nose; II, the base of the nose to the eyebrows; III, above the brows. We analyzed the effect of multiple factors on outcome. From January 1, 2000, to December 31, 2010, we treated 720 patients with GSWBIF (539 males, 75%), with a median age of 29 years. The wounding agent was handgun in 41%, explosive (shotgun and blast) in 20%, rifle in 6%, and unknown in 33%. Prehospital or resuscitative phase airway was required in 236 patients (33%). Definitive care was rendered by multiple specialties in 271 patients (38%). Overall, 185 patients died (26%), 146 (79%) within 48 hours. Of the 481 patients hospitalized greater than 48 hours, 184 had at least one complication (38%). Factors significantly associated with any of a total of 207 complications were total number of operations (p < 0.001), Revised Trauma Score (RTS, p < 0.001), and head Abbreviated Injury Scale (AIS) score (p < 0.05). Factors significantly associated with mortality were RTS (p < 0.001), head AIS score (p < 0.001), total number of operations (p < 0.001), and age (p < 0.05). An injury located in Zone III was independently associated with mortality (p < 0.001). GSWBIFs have high mortality and are associated with significant morbidity. The multispecialty involvement required for definitive care necessitates triage to a trauma center and underscores the need for an organized approach and the development of effective guidelines. Therapeutic/care management, level III.
    Full-text · Article · Jan 2014
  • Jesse Bandle · Steven R Shackford · Carol Beth Sise · M Margaret Knudson

    No preview · Article · Jan 2014
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    ABSTRACT: Recent innovations in care have improved survival following injury. Coincidentally, the population of elderly injured patients with preexisting comorbidities has increased. We hypothesized that this increase in elderly injured patients may have combined with recent care innovations to alter the causes of death after trauma. We reviewed demographics, injury characteristics, and cause of death of in-hospital deaths of patients admitted to our Level I trauma service from 2000 through 2011. Cause of death was classified as acute hemorrhagic shock; severe traumatic brain injury or high spinal cord injury; complications of preexisting medical condition only (PM); survivable trauma combined with complications of preexisting medical condition (TCoM); multiple-organ failure, sepsis, or adult respiratory distress syndrome (MOF/S/ARDS), or trauma not otherwise categorized (e.g., asphyxiation). Major trauma care advances implemented on our service during the period were identified, and trends in the causes of death were analyzed. Of the 27,276 admissions, 819 (3%) eligible nonsurvivors were identified for the cause-of-death analyses. Causes of death were severe traumatic brain injury or high spinal cord injury at 44%, acute hemorrhagic shock at 28%, PM at 11%, TCoM at 10%, MOF/S/ARDS at 2%, and trauma not otherwise categorized at 5%. Mean age at death increased across the study interval (range, 47-57 years), while mean Injury Severity Score (ISS) decreased (range, 28-35). There was a significant increase in deaths because of TCoM (3.3-20.9%) and PM (6.7-16.4%), while deaths caused by MOF/S/ARDS decreased from 5% to 0% by 2007. Compared with year 2000, the annual adjusted mortality rate decreased consistently starting in 2009, after the 2002 to 2007 adoption of four major trauma practice guidelines. Mortality caused by preexisting medical conditions has increased, while markedly fewer deaths resulted from the complications of injury. Future improvements in outcomes will require improvement in the management of elderly trauma patients with comorbid conditions. Epidemiologic, level III.
    Full-text · Article · Jul 2013

  • No preview · Article · Jun 2013

  • No preview · Article · May 2013 · Journal of Trauma and Acute Care Surgery
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    ABSTRACT: BACKGROUND: Major peripheral vascular trauma is managed by several surgical specialties. The impact of surgical specialty training and certification on outcome has not been evaluated. We hypothesized that general surgeons without specialty training in vascular surgery would have outcomes equivalent to surgeons with vascular training in the management of extremity arterial injuries requiring interposition grafting. METHODS: We performed a multicenter, retrospective study of patients undergoing interposition grafting for peripheral vascular injury between 1995 and 2010. Specialty was defined by training and certification. Outcomes were recorded at the time of discharge from the index hospitalization. Factors affecting limb salvage were determined using logistic regression. RESULTS: From the 11 participating centers, 615 patients were identified. General surgeons performed 69.9%, cardiac/vascular surgeons performed 27.3%, and surgeons of other specialties performed 2.8% of the grafts. There were 32 amputations (5.2%). Outcomes did not differ by institution. Factors associated with amputation were blunt mechanism, older age, female sex, hospital length of stay, and Injury Severity Score (ISS). There was no significant difference in limb salvage among specialty groups (general surgeons, 94%; cardiac/vascular, 95%; other, 100%). CONCLUSION: Limb salvage following major peripheral vascular injury is independent of surgeon specialty training. The majority of complex repairs are performed by general surgeons. LEVEL OF EVIDENCE: Therapeutic/care management, level III.
    Full-text · Article · Mar 2013

Publication Stats

12k Citations
820.00 Total Impact Points


  • 2011-2013
    • Mercy Medical Center
      Мейсон-Сити, Iowa, United States
  • 1994-2010
    • University of Vermont
      • Department of Surgery
      Burlington, Vermont, United States
  • 1981-2010
    • University of California, San Diego
      • • Department of Surgery
      • • Division of Cardiothoracic Surgery
      San Diego, California, United States
  • 1992-2009
    • University of Vermont Medical Center
      Burlington, Vermont, United States
    • Vanderbilt University
      • Department of Surgery
      Nashville, MI, United States
  • 2002-2008
    • Fletcher Allen Health Care
      Burlington, Vermont, United States
  • 1998
    • University of North Carolina at Chapel Hill
      North Carolina, United States
  • 1995
    • University of California, San Francisco
      • Department of Surgery
      San Francisco, CA, United States
  • 1981-1994
    • Naval Medical Center San Diego
      • • Vascular Surgery Clinic
      • • Department of Emergency Medicine
      • • Department of Clinical Investigations
      San Diego, California, United States
  • 1984-1988
    • Vibra Hospital of San Diego
      San Diego, California, United States
  • 1987
    • University of South Alabama
      • USA Pediatric Surgery
      Mobile, Alabama, United States
  • 1977
    • California College San Diego
      San Diego, California, United States