R. Shayn Martin

Prospective Trial of Angiography and Embolization for All Grade III to V Blunt Splenic Injuries: Nonoperative Management Success Rate Is Significantly Improved

BACKGROUND Nonoperative management (NOM) of blunt splenic injury is well accepted. Substantial failure rates in higher injury grades remain common, with one large study reporting rates of 19.6%, 33.3%, and 75% for grades III, IV, and V, respectively. Retrospective data show angiography and embolization can increase salvage rates in these severe injuries. We developed a protocol requiring referral of all blunt splenic injuries, grades III to V, without indication for immediate operation for angiography and embolization. We hypothesized that angiography and embolization of high-grade blunt splenic injury would reduce NOM failure rates in this population. STUDY DESIGN This was a prospective study at our Level I trauma center as part of a performance-improvement project. Demographics, injury characteristics, and outcomes were compared with historic controls. The protocol required all stable patients with grade III to V splenic injuries be referred for angiography and embolization. In historic controls, referral was based on surgeon preference. RESULTS From January 1, 2010 to December 31, 2012, there were 168 patients with grades III to V spleen injuries admitted; NOM was undertaken in 113 (67%) patients. The protocol was followed in 97 patients, with a failure rate of 5%. Failure rate in the 16 protocol deviations was 25% (p = 0.02). Historic controls from January 1, 2007 to December 31, 2009 were compared with the protocol group. One hundred and fifty-three patients with grade III to V injuries were admitted during this period, 80 (52%) patients underwent attempted NOM. Failure rate was significantly higher than for the protocol group (15%, p = 0.04). CONCLUSIONS Use of a protocol requiring angiography and embolization for all high-grade spleen injuries slated for NOM leads to a significantly decreased failure rate. We recommend angiography and embolization as an adjunct to NOM for all grade III to V splenic injuries.

Emergency department length of stay is an independent predictor of hospital mortality in trauma activation patients

BACKGROUND The early resuscitation occurs in the emergency department (ED) where intensive care unit protocols do not always extend and monitoring capabilities vary. Our hypothesis is that increased ED length of stay (LOS) leads to increased hospital mortality in patients not undergoing immediate surgical intervention. METHODS We examined all trauma activation admissions from January 2002 to July 2009 admitted to the Trauma Service (n = 3,973). Exclusion criteria were as follows: patients taken to the operating room within the first 2 hours of ED arrival, nonsurvivable brain injury, and ED deaths. Patients spending >5 hours in the ED were not included in the analysis because of significantly lower acuity and mortality. RESULTS Patients spent a mean of 3.2 hours ± 1 hour in the ED during their initial evaluation. Hospital mortality increases for each additional hour a patient spends in the ED, with 8.3% of the patients staying in the ED between 4 hours and 5 hours ultimately dying (p = 0.028). ED LOS measured in minutes is an independent predictor of mortality (odds ratio, 1.003; 95% confidence interval, 1.010-1.006; p = 0.014) when accounting for Injury Severity Score, Revised Trauma Score, and age. Linear regression showed that a longer ED LOS was associated with anatomic injury pattern rather than physiologic derangement. CONCLUSION In this patient population, a longer ED LOS is associated with an increased hospital mortality even when controlling for physiologic, demographic, and anatomic factors. This highlights the importance of rapid progression of patients through the initial evaluation process to facilitate placement in a location that allows implementation of early goal directed trauma resuscitation.

Venovenous extracorporeal life support improves survival in adult trauma patients with acute hypoxemic respiratory failure: A multicenter retrospective cohort study

BACKGROUND Venovenous extracorporeal life support (VV ECLS) has been reported in adult trauma patients with severe respiratory failure; however, ECLS is not available in many trauma centers, few trauma surgeons have experience initiating ECLS and managing ECLS patients, and there is currently little evidence supporting its use in severely injured patients. This study seeks to determine if VV ECLS improves survival in such patients. METHODS Data from two American College of Surgeons–verified Level 1 trauma centers, which maintain detailed records of patients with acute hypoxemic respiratory failure (AHRF), were evaluated retrospectively. The study population included trauma patients between 16 years and 55 years of age treated for AHRF between January 2001 and December 2009. These patients were divided into two cohorts as follows: patients who received VV ECLS after an incomplete or no response to other rescue therapies (ECLS) versus patients who were managed with mechanical ventilation (CONV). The primary outcome was survival to discharge, and secondary outcomes were intensive care unit and hospital length of stay (LOS), total ventilator days, and rate of complications requiring intervention. RESULTS Twenty-six ECLS patients and 76 CONV patients were compared. Adjusted survival was greater in the ECLS group (adjusted odds ratio, 0.193; 95% confidence interval, 0.042–0.884; p = 0.034). Ventilator days, intensive care unit LOS, and hospital LOS did not differ between the groups. ECLS patients received more blood transfusions and had more bleeding complications, while the CONV patients had more pulmonary complications. A cohort of 17 ECLS and 17 CONV patients matched for age and lung injury severity also demonstrated a significantly greater survival in the ECLS group (adjusted odds ratio, 0.038; 95% confidence interval, 0.004–0.407; p = 0.007). CONCLUSION VV ECLS is independently associated with survival in adult trauma patients with AHRF. ECLS should be considered in trauma patients with AHRF when conventional therapies prove ineffective; if ECLS is not readily available, transfer to an ECLS center should be pursued. LEVEL OF EVIDENCE Therapeutic study, level III.

Methamphetamine-induced alterations in dopamine transporter function.

Repeated methamphetamine (METH) administration has been shown to produce differing neurochemical as well as behavioral effects in rats. This study was designed to examine the effects of acute and chronic METH exposure on uptake and release of [3H]dopamine (DA) in cultured midbrain dopamine neurons to determine if persistent neuronal adaptations ensue. In addition, we have assessed DA D2 receptor function to determine if chronic METH alters this receptor. Fetal midbrain cultures were exposed to METH (1, 10 microM) for 5 days and dopaminergic function examined 1 or 7 days after drug removal. The ability of METH to release [3H]DA was compared to other releasing agents as well as several potent uptake inhibitors. Chronic exposure to a release-promoting concentration of METH resulted in either no change or a reduction in [3H]DA release upon subsequent METH challenge. Pretreatment with METH was also found to cause a decrease in the Bmax for [3H]raclopride binding, suggesting that persistently elevated DA levels cause a downregulation of DA D2 receptors. Examination of transporter kinetics utilizing initial velocity of uptake revealed that METH treatment caused a significant decrease in affinity (K(m)) for the substrate (DA), while not altering the maximal velocity of uptake (Vmax). Binding studies with [125I]RTI-55 revealed that there was no alteration in either the Bmax or Kd for this ligand, suggesting that the changes induced by METH treatment are due to alterations in K(m) and not in the number of DA transport sites. The results from these studies indicate that METH treatment produces a modification in transporter function which may be associated with both the altered uptake and release of [3H]DA. These changes have broad implications for the regulation of transporter activity not only because of the relevance to pre-synaptic mechanisms controlling neurotransmission, but also to the importance of the neuronal adaptation that occurs in response to chronic METH exposure.

Characterization of crash-induced thoracic loading resulting in pulmonary contusion

BACKGROUND Pulmonary contusion (PC) is commonly sustained in motor vehicle crash. This study utilizes the Crash Injury Research and Engineering Network (CIREN) database and vehicle crash tests to characterize the occupants and loading characteristics associated with PC. A technique to match CIREN cases to vehicle crash tests is applied to quantify the thoracic loading associated with this injury. METHODS The CIREN database and crash test data from the National Highway Traffic Safety Administration were used in this study. An analysis of CIREN data were conducted between three study cohorts: patients that sustained PC and any other chest injury (PC+ and chest+), patients with chest injury and an absence of PC (PC- and chest+), and a control group without chest injury and an absence of PC (PC- and chest-). Forty-one lateral impact crash tests were analyzed and thoracic loading data from onboard crash tests dummies were collected. RESULTS The incidence of PC in CIREN data were 21.7%. Crashes resulting in PC demonstrated significantly greater mortality (23.9%) and Injury Severity Score (33.1 +/- 15.7) than the control group. The portion of lateral impacts increased from 27% to 48% between the control group and PC+ and chest+ cohort, prompting the use of lateral impact crash tests for the case-matching portion of the study. Crash tests were analyzed in two configurations; vehicle-to-vehicle tests and vehicle-to-pole tests. The average maximum chest compression and deflection velocity from the dummy occupants were found to be 25.3% +/- 2.6% and 4.6 m/s +/- 0.42 m/s for the vehicle-to-pole tests and 23.0% +/- 4.8% and 3.9 m/s +/- 1.1 m/s for the vehicle-to-vehicle tests. Chest deflection versus time followed a roughly symmetric and sinusoidal profile. Sixteen CIREN cases were identified that matched the vehicle crash tests. Of the 16 matched cases, 12 (75%) sustained chest injuries, with half of these patients presenting with PC. CONCLUSIONS Quantified loading at the chest wall indicative of PC and chest injury in motor vehicle crash is valuable boundary condition data for bench-top studies or computer simulations focused on this injury. In addition, because PC often exhibits a delayed onset, knowing the population and crash modes highly associated with this injury may promote earlier detection and improved management of this injury.

Development of a Time Sensitivity Score for Frequently Occurring Motor Vehicle Crash Injuries

BACKGROUND Injury severity alone is a poor indicator of the time sensitivity of injuries. The purpose of the study was to quantify the urgency with which the most frequent motor vehicle crash injuries require treatment, according to expert physicians. STUDY DESIGN The time sensitivity was quantified for the top 95% most frequently occurring Abbreviated Injury Scale (AIS) 2+ injuries in the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) 2000-2011. A Time Sensitivity Score was developed using expert physician survey data in which physicians were asked to determine whether a particular injury should go to a Level I/II trauma center and the urgency with which that injury required treatment. RESULTS When stratifying by AIS severity, the mean Time Sensitivity Score increased with increasing AIS severity. The mean Time Sensitivity Scores by AIS severity were as follows: 0.50 (AIS 2); 0.78 (AIS 3); 0.92 (AIS 4); 0.97 (AIS 5); and 0.97 (AIS 6). When stratifying by anatomical region, the head, thorax, and abdomen were the most time sensitive. CONCLUSIONS Appropriate triage depends on multiple factors, including the severity of an injury, the urgency with which it requires treatment, and the propensity of a significant injury to be missed. The Time Sensitivity Score did not correlate highly with the widely used AIS severity scores, which highlights the inability of AIS scores to capture all aspects of injury severity. The Time Sensitivity Score can be useful in Advanced Automatic Crash Notification systems for identifying highly time sensitive injuries in motor vehicle crashes requiring prompt treatment at a trauma center.

Predicting patients that require care at a trauma center: Analysis of injuries and other factors

INTRODUCTION The detection of occult or unpredictable injuries in motor vehicle crashes (MVCs) is crucial in correctly triaging patients and thus reducing fatalities. The purpose of the study was to develop a metric that indicates the likelihood that an injury sustained in a MVC would require management at a Level I/II trauma centre (TC) versus a non-trauma centre (non-TC). METHODS Transfer Scores (TSs) were computed for 240 injuries that comprise the top 95% most frequently occurring injuries in the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) with an Abbreviated Injury Scale (AIS) severity of 2 or greater. A TS for each injury was computed using the proportions of patients involved in a MVC from the National Inpatient Sample (NIS) that were transferred to a TC or managed at a non-TC. Similarly, a TSMAIS that excludes patients with higher severity co-injuries was calculated using the proportion of patients with a maximum AIS (MAIS) equal to the AIS severity of a given injury. RESULTS The results indicated for injuries of a given AIS severity, body region, and injury type, there were large variations in the TSMAIS. Overall results demonstrated higher TSMAIS values when injuries were internal, haemorrhagic, intracranial or of moderate severity (AIS 3-5). Specifically, injuries to the head possessed a TSMAIS that ranged from 0.000 to 0.889, with head injuries of AIS 3-5 severities being the most likely to be transferred. DISCUSSION AND CONCLUSIONS The analysis indicated that the TSMAIS is not solely correlated with AIS severity and therefore it captures other important aspects of injury such as predictability and trauma system capabilities. The TS and TSMAIS can be useful in advanced automatic crash notification (AACN) research for the detection of highly unpredictable injuries in MVCs that require direct transport to a TC.

Development of a robust mapping between AIS 2+ and ICD-9 injury codes

Motor vehicle crashes result in millions of injuries and thousands of deaths each year in the United States. While most crash research datasets use Abbreviated Injury Scale (AIS) codes to identify injuries, most hospital datasets use the International Classification of Diseases, version 9 (ICD-9) codes. The objective of this research was to establish a one-to-one mapping between AIS and ICD-9 codes for use with motor vehicle crash injury research. This paper presents results from investigating different mapping approaches using the most common AIS 2+ injuries from the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS). The mapping approaches were generated from the National Trauma Data Bank (NTDB) (428,637 code pairs), ICDMAP (2500 code pairs), and the Crash Injury Research and Engineering Network (CIREN) (4125 code pairs). Each approach may pair given AIS code with more than one ICD-9 code (mean number of pairs per AIS code: NTDB=211, ICDMAP=7, CIREN=5), and some of the potential pairs are unrelated. The mappings were evaluated using two comparative metrics coupled with qualitative inspection by an expert physician. Based on the number of false mappings and correct pairs, the best mapping was derived from CIREN. AIS and ICD-9 codes in CIREN are both manually coded, leading to more proper mappings between the two. Using the mapping presented herein, data from crash and hospital datasets can be used together to better understand and prevent motor vehicle crash injuries in the future.

Multidrug-Resistant Pathogens and Pneumonia: Comparing the Trauma and Surgical Intensive Care Units

BACKGROUND As acute care surgery evolves, more trauma surgeons are caring for critically ill general surgery as well as trauma patients. However, these two populations are unique, and infectious complications may need to be addressed differently, as the causative organisms may not be the same in the two groups. To study this, we evaluated ventilator-associated (VAP) and hospital-acquired (HAP) pneumonia in the trauma (TICU) and general surgical (SICU) intensive care units to investigate differences in the causative pathogens. Our hypothesis was that SICU patients would have a higher incidence of multi-drug-resistant (MDR) organisms causing VAP/HAP, possibly contributing to inadequate empiric antibiotic (IEA) coverage. METHODS Retrospective review of 116 patients admitted with VAP or HAP over a one-year period to the TICU (n = 72) or SICU (n = 44) at a tertiary medical center. Culture was followed by initiation of empiric antibiotics on the basis of an antibiotic algorithm derived from trauma patients. Demographics, illness, and pneumonia characteristics were assessed; MDR organisms were identified. RESULTS Multi-drug-resistant organisms caused 30.6% of first pneumonias in the TICU vs. 65.9% in the SICU (p = 0.0002). Subsequent pneumonias were seen in 31.8% of SICU patients and 16.7% of TICU patients (p = 0.0576). Inadequate empiric antibiotic coverage was documented in 38.6% of SICU pneumonias vs. 26.4% in the TICU (p = 0.12). CONCLUSIONS Multiply-resistant pathogens cause a significantly greater number of VAP/HAPs in the SICU than in the TICU. Associated with this, when using an antibiotic algorithm based on TICU bacterial pathogens, there is a trend toward a greater likelihood of subsequent pneumonias and toward more IEA coverage in the SICU population compared with TICU patients. Our results indicate that these distinct patient populations have different pathogens causing VAP/HAP and affirm the necessity for population-specific algorithms to tailor empiric coverage for presumed VAP/HAP.

Comparison of Organ Location, Morphology, and Rib Coverage of a Midsized Male in the Supine and Seated Positions

The location and morphology of abdominal organs due to postural changes have implications in the prediction of trauma via computational models. The purpose of this study is to use data from a multimodality image set to devise a method for examining changes in organ location, morphology, and rib coverage from the supine to seated postures. Medical images of a male volunteer (78.6 ± 0.77 kg, 175 cm) in three modalities (Computed Tomography, Magnetic Resonance Imaging (MRI), and Upright MRI) were used. Through image segmentation and registration, an analysis between organs in each posture was conducted. For the organs analyzed (liver, spleen, and kidneys), location was found to vary between postures. Increases in rib coverage from the supine to seated posture were observed for the liver, with a 9.6% increase in a lateral projection and a 4.6% increase in a frontal projection. Rib coverage area was found to increase 11.7% for the spleen. Morphological changes in the organs were also observed. The liver expanded 7.8% cranially and compressed 3.4% and 5.2% in the anterior-posterior and medial-lateral directions, respectively. Similar trends were observed in the spleen and kidneys. These findings indicate that the posture of the subject has implications in computational human body model development.