Jonathan D. Gates

Prospective Study of Blunt Aortic Injury: Multicenter Trial of the American Association for the Surgery of Trauma

BACKGROUND Blunt aortic injury is a major cause of death from blunt trauma. Evolution of diagnostic techniques and methods of operative repair have altered the management and posed new questions in recent years. METHODS This study was a prospectively conducted multi-center trial involving 50 trauma centers in North America under the direction of the Multi-institutional Trial Committee of the American Association for the Surgery of Trauma. RESULTS There were 274 blunt aortic injury cases studied over 2.5 years, of which 81% were caused by automobile crashes. Chest computed tomography and transesophageal echocardiography were applied in 88 and 30 cases, respectively, and were 75 and 80% diagnostic, respectively. Two hundred seven stable patients underwent planned thoracotomy and repair. Clamp and sew technique was used in 73 (35%) and bypass techniques in 134 (65%). Overall mortality was 31%, with 63% of deaths being attributable to aortic rupture; mortality was not affected by method of repair. Paraplegia occurred postoperatively in 8.7%. Logistic regression analysis demonstrated clamp and sew (p = 0.002) and aortic cross clamp time of > or = 30 minutes (p = 0.01) to be associated with development of postoperative paraplegia. CONCLUSIONS Rupture after hospital admission remains a major problem. Although newer diagnostic techniques are being applied, at this time aortography remains the diagnostic standard. Aortic cross clamp time beyond 30 minutes was associated with paraplegia; bypass techniques, which provide distal aortic perfusion, produced significantly lower paraplegia rates than the clamp and sew approach.

The effect of a rapid response team on major clinical outcome measures in a community hospital.

Objective:To determine the effect of a rapid response system composed primarily of a rapid response team led by physician assistants on the rates of in-hospital cardiac arrests, total and unplanned intensive care unit admissions, and hospital mortality. Design:Prospective, controlled, before and after trial. Setting:A 350-bed nonteaching community hospital. Patients:All adult patients admitted to the hospital from May 1, 2005, to October 1, 2006. Interventions:We introduced a hospital-wide rapid response system that included a rapid response team (RRT) led by physician assistants with specialized critical care training. Measurements and Main Results:We measured the incidence of cardiac arrests that occurred outside of the intensive care unit, total intensive care unit admissions, unplanned intensive care unit admissions, intensive care unit length of stay, and the total hospital mortality rate occurring over the study period. There were 344 RRT calls during the study period. In the 5 months before the rapid response system began, there were an average of 7.6 cardiac arrests per 1,000 discharges per month. In the subsequent 13 months, that figure decreased to 3.0 cardiac arrests per 1,000 discharges per month. Overall hospital mortality the year before the rapid response system was 2.82% and decreased to 2.35% by the end of the RRT year. The percentage of intensive care unit admissions that were unplanned decreased from 45% to 29%. Linear regression analysis of key outcome variables showed strong associations with the implementation of the rapid response system, as did analysis of variables over time. Physician assistants successfully managed emergency airway situations without assistance in the majority of cases. Conclusions:The deployment of an RRT led by physician assistants with specialized skills was associated with significant decreases in rates of in-hospital cardiac arrest and unplanned intensive care unit admissions.

Intracranial EEG versus flumazenil and glucose PET in children with extratemporal lobe epilepsy.

Objective: To compare abnormalities determined in 2-deoxy-2-[18F]fluoro-d-glucose (FDG) and [11C]flumazenil (FMZ) PET images with intracranial EEG data in patients with extratemporal lobe epilepsy. Background: Although PET studies with FDG and FMZ are being used clinically to localize epileptogenic regions in patients with refractory epilepsy, the electrophysiologic significance of the identified PET abnormalities remains poorly understood. Methods: We studied 10 patients, mostly children (4 boys, 6 girls, aged 2 to 19 years; mean age, 11 years), who underwent FDG and FMZ PET scans, intracranial EEG monitoring, and cortical resection for intractable epilepsy. EEG electrode positions relative to the brain surface were determined from MRI image volumes. Cortical areas of abnormal glucose metabolism or FMZ binding were determined objectively based on asymmetry measures derived from homotopic cortical areas at three asymmetry thresholds. PET data were then coregistered with the MRI and overlaid on the MRI surface. A receiver operating characteristics (ROC) analysis was performed to determine the specificity and sensitivity of PET-defined abnormalities against the gold standard of intracranial EEG data. Results: FMZ PET detected at least part of the seizure onset zone in all subjects, whereas FDG PET failed to detect the seizure onset region in two of 10 patients. The area under the ROC curves was higher for FMZ than FDG PET for both seizure onset (p = 0.01) and frequent interictal spiking (p = 0.04). Both FMZ and FDG PET showed poor performance for detection of rapid seizure spread (area under the ROC curve not significantly different from 0.5). Conclusions: [11C]flumazenil (FMZ) PET is significantly more sensitive than 2-deoxy-2-[18F]fluoro-d-glucose (FDG) PET for the detection of cortical regions of seizure onset and frequent spiking in patients with extratemporal lobe epilepsy, whereas both FDG and FMZ PET show low sensitivity in the detection of cortical areas of rapid seizure spread. The application of PET, in particular FMZ PET, in guiding subdural electrode placement in refractory extratemporal lobe epilepsy will enhance coverage of the epileptogenic zone.

Inferior Vena Cava Filter Removal after 317-day Implantation

A Günther Tulip inferior vena cava (IVC) filter was placed prophylactically in a 22-year-old trauma victim with spinal injuries. Attempts to retrieve the filter at 21 and 25 days after placement were aborted as a result of clot trapped in the filter. Despite the possible risk of an IVC laceration, a third attempt was made 317 days after placement in view of the young age of the patient. The filter started collapsing into the retrieval sheath but could not easily be separated from the IVC. During attempted redeployment, the filter would not reopen. The filter was ultimately retrieved with use of additional force. A mild stenosis of the IVC was noted immediately after retrieval. However, the IVC returned to its preretrieval diameter as seen on a 3-month follow-up venogram.

Perivascular graft heparin delivery using biodegradable polymer wraps.

Heparin remains the gold-standard inhibitor of the processes involved in the vascular response to injury. Though this compound has profound and wide-reaching effects on vascular cells in culture and animal models, its clinical utility has been questionable at best. It is clear that the mode of heparin delivery is critical to its potential and it may well be that routine forms of administration are insufficient to observe benefit given the heparins short half-life and complex pharmacokinetics. When ingested orally, heparin is degraded to inactive oligomer fragments while systemic administration is complicated by the need for continuous infusion and the potential for uncontrolled hemorrhage. Thus alternative heparin delivery systems have been proposed to maximize regional effects while limiting systemic toxicity. Yet, as heparin is such a potent antithrombotic compound and since existing local delivery systems lack the ability to precisely regulate release kinetics, even site-specific therapy is prone to bleeding. We now describe the design and development of a novel biodegradable system for the perivascular delivery of heparin to the blood vessel wall with well-defined release kinetics. This system consists of heparin-encapsulated poly(DL lactide-co-glycolide) (pLGA) microspheres sequestered in an alginate gel. Controlled release of heparin from this heterogeneous system could be obtained over a period of 25 days in vitro. The experimental variables affecting heparin release from these matrices were investigated. Gel permeation chromatography (GPC) and scanning electron microscopy (SEM) were used to monitor the degradation process and found to correlate well with the release kinetics. Heparin-releasing gels inhibited growth of bovine vascular smooth muscle cells in tissue culture in a dose-dependent manner. Moreover, gel release controlled vascular injury in denuding and interposition vascular graft animal models of disease even when uncontrolled bleeding was evident with standard matrix-type release. This system may therefore provide an effective means of examining the effects of various compounds in the control of smooth muscle cell proliferation in accelerated arteriopathies and also shed light on the biologic nature of these processes.

Axillary artery injuries secondary to anterior dislocation of the shoulder

We describe a case report of an axillary artery injury after recurrent anterior dislocation of the shoulder. Review of 22 reported cases reveals that 27% are recurrent dislocations, 86% occurred in patients older than 50, 86% of the injuries are in the third part of the axillary artery, and 68% presented with an axillary mass.

The initial response to the Boston marathon bombing: lessons learned to prepare for the next disaster.

Objective:We discuss the strengths of the medical response to the Boston Marathon bombings that led to the excellent outcomes. Potential shortcomings were recognized, and lessons learned will provide a foundation for further improvements applicable to all institutions. Background:Multiple casualty incidents from natural or man-made incidents remain a constant global threat. Adequate preparation and the appropriate alignment of resources with immediate needs remain the key to optimal outcomes. Methods:A collaborative effort among Bostons trauma centers (2 level I adult, 3 combined level I adult/pediatric, 1 freestanding level I pediatric) examined the details and outcomes of the initial response. Each center entered its respective data into a central database (REDCap), and the data were analyzed to determine various prehospital and early in-hospital clinical and logistical parameters that collectively define the citywide medical response to the terrorist attack. Results:A total of 281 people were injured, and 127 patients received care at the participating trauma centers on that day. There were 3 (1%) immediate fatalities at the scene and no in-hospital mortality. A majority of the patients admitted (66.6%) suffered lower extremity soft tissue and bony injuries, and 31 had evidence for exsanguinating hemorrhage, with field tourniquets in place in 26 patients. Of the 75 patients admitted, 54 underwent urgent surgical intervention and 12 (22%) underwent amputation of a lower extremity. Conclusions:Adequate preparation, rapid logistical response, short transport times, immediate access to operating rooms, methodical multidisciplinary care delivery, and good fortune contributed to excellent outcomes.

Successful Nonoperative Management of the Most Severe Blunt Liver Injuries: A Multicenter Study of the Research Consortium of New England Centers for Trauma

HYPOTHESIS Grade 4 and grade 5 blunt liver injuries can be safely treated by nonoperative management (NOM). DESIGN Retrospective case series. SETTING Eleven level I and level II trauma centers in New England. PATIENTS Three hundred ninety-three adult patients with grade 4 or grade 5 blunt liver injury who were admitted between January 1, 2000, and January 31, 2010. MAIN OUTCOME MEASURE Failure of NOM (f-NOM), defined as the need for a delayed operation. RESULTS One hundred thirty-one patients (33.3%) were operated on immediately, typically because of hemodynamic instability. Among 262 patients (66.7%) who were offered a trial of NOM, treatment failed in 23 patients (8.8%) (attributed to the liver in 17, with recurrent liver bleeding in 7 patients and biliary peritonitis in 10 patients). Multivariate analysis identified the following 2 independent predictors of f-NOM: systolic blood pressure on admission of 100 mm Hg or less and the presence of other abdominal organ injury. Failure of NOM was observed in 23% of patients with both independent predictors and in 4% of those with neither of the 2 independent predictors. No patients in the f-NOM group experienced life-threatening events because of f-NOM, and mortality was similar between patients with successful NOM (5.4%) and patients with f-NOM (8.7%) (P = .52). Among patients with successful NOM, liver-specific complications developed in 10.0% and were managed definitively without major sequelae. CONCLUSIONS Nonoperative management was offered safely in two-thirds of grade 4 and grade 5 blunt liver injuries, with a 91.3% success rate. Only 6.5% of patients with NOM required a delayed operation because of liver-specific issues, and none experienced life-threatening complications because of the delay.

Thigh ischemia complicating femoral vessel cannulation for cardiopulmonary bypass

Compartment syndrome of the lower leg is an occasional complication of prolonged ischemia and reperfusion. Compartment syndrome of the thigh is a less well-recognized complication. We present 2 patients with compartment syndrome of the ipsilateral thigh after femoral arterial and venous cannulation for cardiopulmonary bypass. Early diagnosis and urgent decompressive fasciotomy may limit the extent of local tissue damage and subsequent myonephropathic syndrome.

Successful Nonoperative Management of the Most Severe Blunt Renal Injuries: A Multicenter Study of the Research Consortium of New England Centers for Trauma

IMPORTANCE Severe renal injuries after blunt trauma cause diagnostic and therapeutic challenges for the treating clinicians. The need for an operative vs a nonoperative approach is debated. OBJECTIVE To determine the rate, causes, predictors, and consequences of failure of nonoperative management (NOM) in grade IV and grade V blunt renal injuries (BRIs). DESIGN Retrospective case series. SETTING Twelve level I and II trauma centers in New England. PARTICIPANTS A total of 206 adult patients with a grade IV or V BRI who were admitted between January 1, 2000, and December 31, 2011. MAIN OUTCOMES AND MEASURES Failure of NOM, defined as the need for a delayed operation or death due to renal-related complications during NOM. RESULTS Of 206 patients, 52 (25.2%) were operated on immediately, and 154 (74.8%) were managed nonoperatively (with the assistance of angiographic embolization for 25 patients). Nonoperative management failed for 12 of the 154 patients (7.8%) and was related to kidney injury in 10 (6.5%). None of these 10 patients had complications because of the delay in BRI management. The mean (SD) time from admission to failure was 17.6 (27.4) hours (median time, 7.5 hours; range, 4.5-102 hours), and the cause was hemodynamic instability in 10 of the 12 patients (83.3%). Multivariate analysis identified 2 independent predictors of NOM failure: older than 55 years of age and a road traffic crash as the mechanism of injury. When both risk factors were present, NOM failure occurred for 27.3% of the patients; when both were absent, there were no NOM failures. Of the 142 patients successfully managed nonoperatively, 46 (32.4%) developed renal-related complications, including hematuria (24 patients), urinoma (15 patients), urinary tract infection (8 patients), renal failure (7 patients), and abscess (2 patients). These patients were managed successfully with no loss of renal units (ie, kidneys). The renal salvage rate was 76.2% for the entire population and 90.3% among patients selected for NOM. CONCLUSIONS AND RELEVANCE Hemodynamically stable patients with a grade IV or V BRI were safely managed nonoperatively. Nonoperative management failed for only 6.5% of patients owing to renal-related injuries, and three-fourths of the entire population retained their kidneys.