Computed tomographic imaging in the pediatric patient with a seatbelt sign: still not good enough.

PURPOSE: Considering the improvements in CT over the past decade, this study aimed to determine whether CT can diagnose HVI in pediatric trauma patients with seatbelt signs (SBS). METHODS: We retrospectively identified pediatric patients with SBS who had abdominopelvic CT performed on initial evaluation over 5 1/2years. Abnormal CT was defined by identification of any intra-abdominal abnormality possibly related to trauma. RESULTS: One hundred twenty patients met inclusion criteria. CT was abnormal in 38/120 (32%) patients: 34 scans had evidence of HVI and 6 showed solid organ injury (SOI). Of the 34 with suspicion for HVI, 15 (44%) had small amounts of isolated pelvic free fluid as the only abnormal CT finding; none required intervention. Ultimately, 16/120 (13%) patients suffered HVI and underwent celiotomy. Three patients initially had a normal CT but required celiotomy for clinical deterioration within 20h of presentation. False negative CT rate was 3.6%. The sensitivity, specificity and accuracy of CT to diagnose significant HVI in the presence of SBS were 81%, 80%, and 80%, respectively. CONCLUSIONS: Despite improvements in CT, pediatric patients with SBS may have HVI not evident on initial CT confirming the need to observation for delayed manifestation of HVI. LEVEL OF EVIDENCE: Level II Study of a Diagnostic Test.

Goal directed enoxaparin dosing provides superior chemoprophylaxis against deep vein thrombosis.

INTRODUCTION: Optimal enoxaparin dosing for deep venous thrombosis (DVT) prophylaxis remains elusive. Prior research demonstrated that trauma patients at increased risk for DVT based upon Greenfield's risk assessment profile (RAP) have DVT rates of 10.8% despite prophylaxis. The aim of this study was to determine if goal directed prophylactic enoxaparin dosing to achieve anti-Xa levels of 0.3-0.5IU/ml would decrease DVT rates without increased complications. MATERIALS AND METHODS: Retrospective review of trauma patients having received prophylactic enoxaparin and appropriately timed anti-Xa levels was performed. Dosage was adjusted to maintain an anti-Xa level of 0.3-0.5IU/ml. RAP was determined on each patient. A score of ≥5 was considered high risk for DVT. Sub-analysis was performed on patients who received duplex examinations subsequent to initiation of enoxaparin therapy to determine the incidence of DVT. RESULTS: 306 patients met inclusion criteria. Goal anti-Xa levels were met initially in only 46% of patients despite dosing of >40mg twice daily in 81% of patients; however, with titration, goal anti-Xa levels were achieved in an additional 109 patients (36%). An average enoxaparin dosage of 0.55mg/kg twice daily was required for adequacy. Bleeding complications were identified in five patients (1.6%) with three requiring intervention. There were no documented episodes of HIT. Subsequent duplex data was available in 197 patients with 90% having a RAP score >5. Overall, five DVTs (2.5%) were identified and all occurred in the high-risk group. All patients were asymptomatic at the time of diagnosis. CONCLUSION: An increased anti-Xa range of 0.3-0.5IU/ml was attainable but frequently required titration of enoxaparin dosage. This produced a lower rate of DVT than previously published without increased complications.

Results of a prospective randomized controlled trial of early ambulation for patients with lower extremity autografts.

It is common practice to keep those patients with lower extremity autografts immobile until post-operative day (POD) 5. There is however inherent risks associated with even short periods of immobility. As of now there are no randomized controlled trials looking at early ambulation of patients with lower extremity autografts in the burn community.The objective of this study was to show that patients who begin ambulation within 24 hours of lower extremity autografting will have no increased risk of graft failure than those patients who remain immobile until POD 5. Thirty-one subjects who received autografts to the lower extremity were randomized after surgery into either the early ambulation group (EAG;17 subjects) or the standard treatment group (STG;14 subjects). Those subjects randomized to the EAG began ambulating with physical therapy on POD 1. Subjects in the STG maintained bed rest until POD 5. There was no difference in the number of patients with graft loss in either the EAG or STG on POD 5, and during any of the follow-up visits. No subjects required regrafting. There was a significant difference in the mean minutes of ambulation, with the EAG ambulating longer than the STG (EAG 23.4 minutes [SD 12.03], STG 14.1 [SD 9.00], P=.0235) on POD 5. Burn patients with lower extremity autografts can safely ambulate on POD 1 without fear of graft failure compared with those patients that remain on bed rest for 5 days.

The ability of computed tomography to diagnose placental abruption in the trauma patient.

BACKGROUND: Fetal demise following trauma remains a devastating complication largely owing to placental injury and abruption. Our objective was to determine if abdominopelvic computed tomographic (CT) imaging can assess for placental abruption (PA) when obtained to exclude associated maternal injuries. METHODS: Retrospective review of pregnant trauma patients of 20-week gestation or longer presenting to a trauma center during a 7-year period who underwent CT imaging as part of their initial evaluation. Radiographic images were reviewed by a radiologist for evidence of PA and classified based on percentage of visualized placental enhancement. Blinded to CT results, charts were reviewed by an obstetrician for clinical evidence of PA and classified as strongly positive, possibly positive, or no evidence. RESULTS: A total of 176 patients met inclusion criteria. CT imaging revealed evidence of PA in 61 patients (35%). As the percentage of placental enhancement decreased, patients were more likely to have strong clinical manifestations of PA, reaching statistical significance when enhancement was less than 50%. CT imaging evidence of PA was apparent in all patients who required delivery for nonassuring fetal heart tones. CONCLUSION: CT imaging evaluation of the placenta can accurately identify PA and therefore can help stratify patients at risk for fetal complications. The likelihood of requiring delivery increased as placental enhancement declined to less than 25%. LEVEL OF EVIDENCE: Diagnostic study, level III.

Incidence of blunt cerebrovascular injury in low-risk cervical spine fractures.

BACKGROUND: It has been suggested that specific cervical spine fractures (CSfx) (location at upper cervical spine [CS], subluxation, or involvement of the transverse foramen) are predictive of blunt cerebrovascular injury (BCVI). We sought to determine the incidence of BCVI with CSfx in the absence of high-risk injury patterns. METHODS: We performed a retrospective study in patients with CSfx who underwent evaluation for BCVI. The presence of recognized CS risk factors for BCVI and other risk factors (Glasgow coma score ≤ 8, skull-based fracture, complex facial fractures, soft-tissue neck injury) were reviewed. Patients were divided into 2 groups based on the presence/absence of risk factors. RESULTS: A total of 260 patients had CSfx. When screened for high-risk pattern of injury for BCVI, 168 patients were identified and 13 had a BCVI (8%). The remaining 92 patients had isolated low CSfx (C4-C7) without other risk factors for BCVI. In this group, 2 patients were diagnosed with BCVI (2%). Failure to screen all patients with CSfx would have missed 2 of 15 BCVIs (13%). CONCLUSIONS: We propose that all CS fracture patterns warrant screening for BCVI.

Use of computed tomography in the initial evaluation of anterior abdominal stab wounds.

BACKGROUND: The purpose of this study was to assess the ability of computed tomography (CT) to facilitate initial management decisions in patients with anterior abdominal stab wounds. METHODS: A retrospective review was conducted of patients with anterior abdominal stab wounds who underwent CT over 4.5 years. Any abnormality suspicious for intra-abdominal injury was considered a positive finding on CT. RESULTS: Ninety-eight patients met the study's inclusion criteria. Positive findings on CT were noted in 30 patients (31%), leading to operative intervention in 67%. Injuries were confirmed in 95% of cases, but only 70% were therapeutic. Ten patients had nonoperative management despite positive findings on CT, including 5 patients with solid organ injuries. One patient underwent operative intervention for clinical deterioration, with negative findings. No computed tomographic evidence of injury was noted in the remaining 68 patients (69%), but 1 patient was noted to have a splenic injury while undergoing operative evaluation of the diaphragm. All remaining patients were treated nonoperatively with success. CONCLUSIONS: In patients with anterior abdominal stab wounds, CT should be considered to facilitate initial management decisions, as it has the ability to delineate abnormalities suspicious for injury.

Risk factors for blunt cerebrovascular injury in children: do they mimic those seen in adults?

BACKGROUND: Eastern Association for the Surgery of Trauma guideline for the evaluation of blunt cerebrovascular injury (BCVI) states that pediatric trauma patients should be evaluated using the same criteria as the adult population. The purpose of our study was to determine whether adult criteria translate to the pediatric population. METHODS: Retrospective evaluation was performed at a Level I trauma center of blunt pediatric trauma patients (age <15 years) presenting over a 5-year period. Data obtained included patient demographics, presence of adult risk factors for BCVI (Glasgow coma scale ≤8, skull base fracture, cervical spine fracture, complex facial fractures, and soft tissue injury to the neck), presence of signs/symptoms of BCVI, method of evaluation, treatment, and outcome. RESULTS: A total of 1,209 pediatric trauma patients were admitted during the study period. While 128 patients met criteria on retrospective review for evaluation based on Eastern Association for the Surgery of Trauma criteria, only 52 patients (42%) received subsequent radiographic evaluation. In all, 14 carotid artery or vertebral artery injuries were identified in 11 patients (all admissions, 0.9% incidence; all screened, 21% incidence). Adult risk factors were present in 91% of patients diagnosed with an injury. Major thoracic injury was found in 67% of patients with carotid artery injuries. Cervical spine fracture was found in 100% of patients with vertebral artery injuries. Stroke occurred in four patients (36%). Stroke rate after admission for untreated patients was 38% (3/8) versus 0.0% in those treated (0/2). Mortality was 27% because of concomitant severe traumatic brain injury. CONCLUSION: Risk factors for BCVI in the pediatric trauma patient appear to mimic those of the adult patient.

A remote in situ monitor based on continuous flow analysis for the quantitation of sub-micromolar levels of hexavalent chromium in natural waters.

We describe the design, optimization, and application of a small, lightweight, deployable monitoring instrument for accurately measuring parts-per-billion levels of hexavalent Cr in surface waters at hourly intervals. The monitor quantifies Cr(vi) using a standard molecular absorbance spectroscopic method, i.e. by formation of a complex with 1,5-diphenylcarbazide (DPC). The continuous flow analysis (CFA) design uses narrow conduits (0.90 mm) that are hot-forged onto poly(methyl methacrylate) ('Plexiglas') plates based on the method of Jannasch et al.(Anal. Chem., 1994, 66, 3352). The sample stream is drawn through the manifold at 25 microl min(-1) using a mini-peristaltic pump; osmotic pumps (10 microl h(-1)) are used to continuously inject reagent (2.0 mM DPC, 0.60 M HNO(3), 5.0% w/v acetone, and 0.10% w/v Brij-35) and to periodically introduce quality control standards and a cleaning solution (0.50 M HNO(3)). The 'Z-type' optical cell uses a liquid-core waveguide (10 mm) to collimate the light-emitting diode source beam (lambda(max) 574 nm) to a broadband photodiode detector. Figures of merit are: 7 min cycle time, response within 28 min and clear-down within 31 min, low waste generation (<40 ml d(-1)), detection limit (3sigma) of 48.4 microg l(-1) as Cr(vi) or 0.411 microM as chromic acid, 1.54% relative standard deviation at 100 microg l(-1), and selectivity for dissolved Cr(vi) in authentic surface water samples containing moderate levels (>0.21% w/v) of total particulate matter. Using a test chamber containing Milwaukee Harbor water that was periodically fortified with Cr(vi) standards, continuous testing over a 15 day period (354 h) yielded results that were in excellent agreement (<5% variation) with measurements made using an ICP-MS reference method. Drift in the calibration model over the test period was 1.23% and the variation in a 0.50 mg l(-1) Cr(vi) standard was 3.8%(n= 11). Known interferences to the DPC chemistry (Mo, V, and Hg at >5 mg l(-1)) were undetected in the harbor water by ICP-MS.