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Biomedical subjects

Allan B Wolfson

Publications and source records attributed to Allan B Wolfson.

11 recordsLinked to original sources
PubMed2006

Prevalence and prognosis of traumatic intraventricular hemorrhage in patients with blunt head trauma.

BACKGROUND: Most studies of traumatic intraventricular hemorrhage (tIVH) contain fewer than 25 subjects and are retrospective in design, providing minimal information about the entity and its clinical significance. METHODS: We prospectively enrolled trauma patients from 18 centers in North America in the National Emergency X-Radiography Utilization Study (NEXUS) II if they received an emergent head computed tomography (CT) scan, as determined by the managing physician. Clinical data were collected at the time of enrollment and CT reports were compiled at least 1 month later. We calculated prevalence and demographics of tIVH from the 18 sites, while outcome data were gathered from medical records of patients with tIVH who were seen at any of six sites that participated in the follow-up portion of the study. We considered patients who underwent a neurosurgical intervention or who had a "poor outcome" (Glasgow Outcome Scale score of 1 to 3, death, persistent vegetative state, or severe disability) to have suffered a "combined outcome." RESULTS: Prevalence of tIVH among all trauma patients who received a head CT was 118 in 8,374, or 1.41%. Among tIVH patients, 70% had a "poor outcome" and 76% had a "combined outcome." A poor outcome appeared to be associated with an abnormal presenting Glasgow Coma Scale score and involvement of the third or fourth ventricle, whereas age appeared to be unrelated. Patients with tIVH and no major associated injury on CT tended to do well; only one patient with isolated tIVH had a poor outcome. CONCLUSIONS: Traumatic IVH is rare and is associated with poor outcomes that seem to be the consequence of associated injuries. Isolated tIVH patients who are clinically well appear to have a functional outcome; we were unable to identify a case of isolated tIVH, combined with a normal neurologic examination, resulting in a poor or combined outcome.

Adolescent↗
PubMed2006

Intracranial pathology in elders with blunt head trauma.

OBJECTIVES: To examine presentations and prevalence of head injury among elder victims of blunt trauma and to estimate the prevalence of occult injuries associated with a normal level of consciousness, absence of neurologic deficit, and no evidence of significant skull fracture. METHODS: The study population consisted of all patients aged 65 years or older enrolled in the National Emergency X-Radiography Utilization Study (NEXUS) II head injury cohort. The authors assessed the prevalence and patterns of intracranial injuries among this cohort and compared the prevalence of specific presenting signs and symptoms among injured and uninjured patients. An occult injury subcohort was also constructed, and injury prevalence was examined among this group. RESULTS: A total of 1,934 elder patients were identified among the 13,326 subjects in NEXUS II (14.5%). Significant intracranial injury, defined as an injury that typically requires procedural intervention or is associated with persistent neurologic impairment or long-term disability, was found in 178 elder patients (9.2%; 95% confidence interval = 8.0% to 10.6%) as compared with 697 individuals among 11,392 younger patients (6.1%; 95% confidence interval = 5.7% to 6.6%). Focal neurologic deficits were present in 55.8% of elder patients with injury. Prevalence of specific injuries among elder and younger patients, respectively, included the following: subdural hematoma, 4.4% and 2.4%; contusion, 4.0% and 3.2%; epidural hematoma, 0.5% and 1.0%; and depressed skull fracture, 0.2% and 0.5%. Forty-two elder patients (2.2%) had an occult injury, compared with only 92 younger patients (0.8%). CONCLUSIONS: Elder patients with head trauma are at higher risk of developing a significant intracranial injury, including subdural and epidural hematoma. An occult presentation is also more common in elders.

Age Distribution↗
PubMed2005

Postpartum focal neurologic deficits: posterior leukoencephalopathy syndrome.

The postpartum patient who presents with focal neurologic deficits presents a wide range of diagnostic possibilities. We report the case of a previously healthy woman who presented 7 days postpartum with a focal deficit and who was ultimately diagnosed with eclampsia and posterior leukoencephalopathy syndrome (PLES). The hallmark of this entity is reversible parieto-occipital white matter edema as seen on magnetic resonance imaging (MRI). Advanced MRI techniques, such as echo-planar diffusion-weighted images and apparent diffusion coefficient maps, suggest cerebral artery dilatation as the underlying mechanism. Laboratory findings and computed tomography (CT) scans are typically unremarkable. PLES has a favorable prognosis if treated promptly and appropriately.

Adult↗
PubMed2005

Developing a decision instrument to guide computed tomographic imaging of blunt head injury patients.

BACKGROUND: Computed tomographic (CT) head scanning of blunt trauma patients is expensive, delays care, and necessitates radiation exposure, while detecting intracranial injuries in a minority of patients. Clinical characteristics may be able reliably identify patients who do not have intracranial injuries and consequently, do no require imaging. METHODS: Physicians assessed blunt trauma patients undergoing imaging for the presence or absence of specific criteria. Recursive partitioning was used to identify criteria that predict intracranial injuries with high sensitivity. RESULTS: Intracranial injuries were found in 917 of 13,728 enrolled patients (6.7%). Injuries were rare among patients under age 65 who had no evidence of skull fracture, scalp hematoma, neurologic deficit, abnormal alertness, abnormal behavior, coagulopathy, or persistent vomiting. These characteristics would have identified 901 injury cases (sensitivity 98.3% [CI: 97.2-99.0]), while classifying 1,752 patients (12.8%) as "low risk." CONCLUSIONS: Clinical characteristics can reliably identify patients who are unlikely to have intracranial injuries and who do not require CT imaging.

Adult↗
PubMed2004

Combining clinical risk with D-dimer testing to rule out deep vein thrombosis.

We sought to determine whether the combination of low-intermediate clinical risk of acute lower extremity deep vein thrombosis (DVT) and negative ELISA D-dimer assay can eliminate the need for duplex ultrasonography. Three hundred thirty-six patients prospectively underwent clinical risk stratification (low, intermediate, and high), D-dimer testing, and duplex ultrasonography. Thirteen of 145 intermediate-risk patients had acute DVT; 11 (85%) had a positive D-dimer. Two of 118 low-risk patients had acute DVT; both had a positive D-dimer. Intermediate-high risk stratification alone had sensitivity of 93.9% (95% CI: 80.3-98.3%) and a NPV of 98.3% (95% CI: 94.0-99.5%) for acute DVT. For all patients, a positive D-dimer alone had a sensitivity of 93.9% (95% CI: 80.3-98.3%) and a NPV of 98.6% (95% CI: 95.1-99.6%). The combination of D-dimer and intermediate-high risk classification had a sensitivity of 100% (95% CI: 89.4-100%) and a NPV of 100% (95% CI: 98.9-100%). In suspected acute lower extremity DVT, the combination of intermediate-high clinical risk and positive D-dimer has a high sensitivity and NPV, possibly eliminating the need for duplex ultrasound in this group of patients.

Adult↗
PubMed2003

Spurious values of serum electrolytes due to admixture of intravenous infusion fluids.

Blood samples may be collected subsequent to the establishment of a working i.v. line. When collected incorrectly, such blood samples can yield spurious results of serum electrolyte and chemistry determinations. We present such a case and, further, show that serum chemistry values can be altered by contamination with i.v. fluids in the emergency patient and that such alterations can be of sufficient magnitude to affect treatment. Recommendations are given regarding aspiration of blood samples from working i.v. lines to minimize the risk of spurious measurements.

Acid-Base Equilibrium↗
PubMed2003

Interrater reliability of criteria used in assessing blunt head injury patients for intracranial injuries.

OBJECTIVE: To determine the interrater reliability of potential predictor variables that may be used to construct a clinical decision rule for emergency computed tomography of the head in blunt head injury victims. METHODS: As a substudy of the NEXUS II study of blunt head trauma, physicians from 21 different emergency departments performed paired evaluations of patients undergoing computed tomography of the head after blunt head injury. Each physician independently determined, for each subject, the presence or absence of each of 19 separate clinical characteristics. The physicians were either residents or attending physicians in the participating emergency departments. Paired responses on a sample of 3,951 patients were compared for raw level of agreement and for interrater concordance using the kappa statistic. If the lower margin of the 95% confidence interval for raw agreement was at least 85% and was equal to or greater than 0.50 for kappa, this was predetermined to represent substantial interrater agreement. RESULTS: There was substantial interobserver agreement by both measures for 17 of the 19 candidate variables in patients with blunt head trauma. Interobserver agreement was substantial for all candidate variables except presence of seizure (kappa = 0.57 [95% CI = 0.47 to 0.67]; raw agreement = 96.5%) and abnormal cerebellar function (kappa = 0.54 [95% CI = 0.41 to 0.67]; raw agreement = 96.5%). CONCLUSIONS: The clinicians in our study had a substantial level of agreement regarding most clinical criteria assessed in this large sample of patients with blunt head injury.

Analysis of Variance↗
PubMed2002

Developing a clinical decision instrument to rule out intracranial injuries in patients with minor head trauma: methodology of the NEXUS II investigation.

The fear of failing to identify brain injury has led to the liberal and potentially excessive use of computed tomographic (CT) scanning of patients with blunt head trauma who have even a remote possibility of intracranial injury. This practice exposes large numbers of patients to the expense and radiation exposure associated with CT imaging while detecting injuries in a small minority. Previous studies suggest that it might be possible to develop a decision instrument to identify patients with blunt head injury who have essentially no risk of significant intracranial injury and for whom CT scanning is therefore unnecessary. Development of such a decision instrument has been identified as a priority among practicing emergency physicians. The National Emergency X-Radiography Utilization Study II (NEXUS II) is a large, multicenter, prospective study designed to derive a decision rule for CT imaging of patients with blunt head injury. This study, conducted in 21 different emergency departments across the United States and Canada, will enroll more than 10 times as many patients with head trauma as any currently published study. NEXUS II should be able to definitively answer questions about the validity and reliability of clinical criteria as a preliminary screen for blunt head trauma.

Brain Injuries↗
PubMed2002

Spinal cord injury without radiographic abnormality: results of the National Emergency X-Radiography Utilization Study in blunt cervical trauma.

BACKGROUND: The purpose of this study was to better define the incidence and characteristics of patients with spinal cord injury without radiographic abnormality (SCIWORA), using the database of the National Emergency X-Radiography Utilization Study (NEXUS). METHODS: This was a prospective, observational study of blunt trauma patients in 21 U.S. medical centers undergoing plain cervical radiography. SCIWORA was defined as spinal cord injury demonstrated by magnetic resonance imaging, when a complete, technically adequate plain radiographic series revealed no injury. RESULTS: Of the 34,069 patients entered, there were 818 (2.4%) with cervical spine injury, including 27 (0.08%) patients with SCIWORA. Over 3,000 children were enrolled, including 30 with cervical spine injury, but none had SCIWORA. The most common magnetic resonance imaging findings among SCIWORA patients were central disc herniation, spinal stenosis, and cord edema or contusion. Central cord syndrome was described in 10 cases. CONCLUSION: In the large NEXUS cohort, SCIWORA was an uncommon disorder, and occurred only in adults.

Adult↗