Assaf Landschaft

An Introduction to Natural Language Processing: How You Can Get More From Those Electronic Notes You Are Generating.

Electronically stored clinical documents may contain both structured data and unstructured data. The use of structured clinical data varies by facility, but clinicians are familiar with coded data such as International Classification of Diseases, Ninth Revision, Systematized Nomenclature of Medicine-Clinical Terms codes, and commonly other data including patient chief complaints or laboratory results. Most electronic health records have much more clinical information stored as unstructured data, for example, clinical narrative such as history of present illness, procedure notes, and clinical decision making are stored as unstructured data. Despite the importance of this information, electronic capture or retrieval of unstructured clinical data has been challenging. The field of natural language processing (NLP) is undergoing rapid development, and existing tools can be successfully used for quality improvement, research, healthcare coding, and even billing compliance. In this brief review, we provide examples of successful uses of NLP using emergency medicine physician visit notes for various projects and the challenges of retrieving specific data and finally present practical methods that can run on a standard personal computer as well as high-end state-of-the-art funded processes run by leading NLP informatics researchers.

How Much Cerebrospinal Fluid Should We Remove Prior to Measuring a Closing Pressure

Objective: The objective of this study was to identify a relationship between cerebrospinal fluid (CSF) volume removal and change in CSF pressure in children with suspected idiopathic intracranial hypertension (IIH). Methods: We performed a cross-sectional study of children 22 years and younger who underwent a lumbar puncture (LP) and had a documented opening pressure, closing pressure, and volume removed. Relationship between volume removal and pressure change was determined using a fractional polynomial regression procedure. Results: In the 297 patients who met the inclusion criteria, CSF pressure decreased by 1 cm H2O for every 0.91 mL of CSF removed if the maximum change in pressure was less than 15 cm H2O (R2 = 0.38). Conclusion: A linear relationship exists between the volume of CSF removed and the amount of pressure relieved when the desired pressure change is less than 15 cm H2O.

Pediatric status epilepticus: How common is cerebrospinal fluid pleocytosis in the absence of infection?

PURPOSE To determine the rate of cerebrospinal fluid (CSF) pleocytosis among children presenting with status epilepticus (SE) without proven central nervous system infection. METHOD We performed a retrospective cross-sectional study of all patients aged one month to 21 years of age who were evaluated in a single pediatric emergency department (ED) for SE between 1995 and 2012. We limited our study to those children who had a CSF culture obtained and excluded those children with proven viral or bacterial infection. We defined SE in a patient who had a single seizure or a cluster of seizures without regaining consciousness which lasted 30 min or longer. We defined CSF pleocytosis as a CSF white blood cells (WBC)>10 cells/mm(3) and a peripheral leukocytosis as WBC ≥ 15,000 cells/mm(3). We compared the rate of CSF pleocytosis between children with and without peripheral leukocytosis using the Fishers exact test. RESULTS We identified 289 ED visits for SE, of which 178 (62%) met study inclusion criteria. Seven children (4%, 95% confidence interval 1.7-8.2%) had CSF pleocytosis. More children with peripheral leukocytosis had CSF pleocytosis: (8.6% with peripheral leukocytosis vs. 0.9% without leukocytosis, p=0.01). CONCLUSION CSF pleocytosis is relatively uncommon among children with prolonged seizures, even in the presence of peripheral leukocytosis. Therefore, all children with CSF pleocytosis after status epilepticus need comprehensive evaluation for central nervous system infection.

The Yield of Neuroimaging in Children Presenting to the Emergency Department With Acute Ataxia in the Post–Varicella Vaccine Era

To determine the yield of neuroimaging in children presenting to the emergency department with acute ataxia in the post–varicella vaccine era, we conducted a cross-sectional study between 1995 and 2013 at a single pediatric tertiary care center. We included children aged 1-18 years evaluated for acute ataxia of <7 days’ duration. The main outcome was clinically urgent intracranial pathology defined as a radiologic finding that changed initial management. We identified 364 children, among whom neuroimaging was obtained in 284 (78%). Forty-two children had clinically urgent intracranial pathology (13%, 95% confidence interval 9%-17%); tumors and acute disseminated encephalomyelitis were the leading findings. Age ≤3 years and symptoms ≤3 days of duration were predictors of low risk (0.7%, 95% confidence interval 0%-4.4%). In conclusion, neuroimaging may be indicated for most patients presenting with acute ataxia. Neuroimaging may be deferred in younger children with short duration of symptoms contingent on close follow-up.

The Frequency of Postreduction Interventions After Successful Enema Reduction of Intussusception.

OBJECTIVES The objective was to determine the frequency of postreduction, hospital-level interventions among children with successful reduction of ileocolic intussusception and identify factors that predict the need for such interventions. METHODS This was a retrospective cross-sectional study of children who underwent successful enema reduction for ileocolic intussusception at a single emergency department. Hospital-level interventions were included if they occurred within 24 hours of reduction and were further classified as either major (recurrence or possible perforation) or minor (imaging for suspected recurrence or administration of parenteral narcotics or antiemetics). Binary logistic regression was used to identify predictors for hospital-level interventions. RESULTS A total of 464 children underwent enema reduction. The median age was 1.7 years (interquartile range [IQR] = 0.8 to 2.5 years), and 66% were male. A total of 435 (94%) were hospitalized with a median hospital stay of 25 hours (IQR = 19 to 34 hours). Nineteen percent (95% confidence interval [CI] = 15% to 22%) needed postreduction interventions, including 6% (95% CI = 4% to 9%) who required major interventions. The median time to any hospital intervention was 9.9 hours (IQR = 6.3 to 16.4 hours). We identified two independent predictors for hospital-level interventions: duration of symptoms > 24 hours (adjusted odds ratio [OR] = 2.1, 95% CI = 1.3 to 3.4) and location of the intussusception tip at (or proximal to) the hepatic flexure (adjusted OR = 1.9, 95% CI = 1.1 to 3.3); the latter factor was also a predictor of a major intervention. None of the children (95% CI = 0 to 1.0%) had an acute decompensation after an initially successful enema reduction. CONCLUSIONS Clinical decompensation is rare and recurrence is relatively low after an uncomplicated reduction of ileocolic intussusception. However, one in five children required hospital-level interventions after reduction. Children with the intussusception tip at (or proximal to) the hepatic flexure, and those with symptoms for longer than 24 hours, are more likely to require subsequent interventions. Although outpatient management appears safe after a period of observation, caregivers should be counseled about the risk of ongoing symptoms and recurrence.

Pediatric Emergency Department Visits for Homelessness After Shelter Eligibility Policy Change

Visits to a pediatric ED for homelessness (frequently without a medical complaint) increased after a change in emergency shelter eligibility regulation, with considerable associated costs. BACKGROUND AND OBJECTIVES: In 2012, Massachusetts changed its emergency shelter eligibility policy for homeless families. One new criterion to document homelessness was staying in a location “not meant for human habitation,” and the emergency department (ED) fulfilled this requirement. Our aim for this study is to analyze the frequency and costs of pediatric ED visits for homelessness before and after this policy. METHODS: This is a retrospective study of ED visits for homelessness at a children’s hospital from March 2010 to February 2016. A natural language processing tool was used to identify cases, which were manually reviewed for inclusion. We compared demographic and homelessness circumstance characteristics and conducted an interrupted time series analysis to compare ED visits by homeless children before and after the policy. We compared the change in ED visits for homelessness to the number of homeless children in Massachusetts. We analyzed payment data for each visit. RESULTS: There were 312 ED visits for homelessness; 95% (n = 297) of visits were after the policy. These visits increased 4.5 times after the policy (95% confidence interval: 1.33 to 15.23). Children seen after the policy were more likely to have no medical complaint (rate ratio: 3.27; 95% confidence interval: 1.18 to 9.01). Although the number of homeless children in Massachusetts increased 1.4 times over the study period, ED visits for homelessness increased 13-fold. Payments (average:

Predictors of Primary Intracranial Hypertension in children, using a newly suggested opening pressure cutoff of 280 mm H2O

557 per visit) were >4 times what a night in a shelter would cost; 89% of payments were made through state-based insurance plans. CONCLUSIONS: A policy change to Massachusetts’ shelter eligibility was associated with increased pediatric ED visits for homelessness along with substantial health care costs.

A method to identify pediatric high-risk diagnoses missed in the emergency department

OBJECTIVES We assessed the clinical characteristics of primary intracranial hypertension (PIH) in children using a newly recommended threshold for cerebrospinal fluid opening pressure (280 mm H2O). METHOD Cross-sectional study of patients age ≤21 years who had a lumbar puncture done for evaluation of PIH. Patients were excluded if lumbar puncture was done for a suspected infection, seizure, mental status changes, multiple sclerosis, or Guillain-Barre syndrome. Cases were identified using a text-search module followed by manual review. We performed χ2 analysis for categorical data and Mann-Whitney U test for continuous data, followed by a binary logistic regression. RESULTS We identified 374 patients of whom 67% were female, median age was 13 years interquartile range (11 to 16 years), and admission rate was 24%. Using an opening pressure cutoff of 250 mm H2O, 127 patients (34%) were identified as having PIH, whereas using the new cutoff 105 patients (28%) met PIH criteria. Predictors for PIH included optic disc edema or sixth nerve palsy using both old, odds ratio (OR) 7.6 (4.3, 13.5), and new cutoffs, OR 9.7 (95% confidence interval 5.1, 18.5). Headache duration ≤61 days is predictive of PIH using the new cutoff OR 4.1 (95% confidence interval 1.3, 12.8). A model is presented which stratifies patients into groups with low (7%), medium (18%), and high (greater than 42%) risk of PIH. CONCLUSIONS A higher cerebrospinal fluid opening pressure threshold in the criteria of PIH is associated with PIH patients with a different symptom profile. Children with optic disc edema, bulging fontanel or sixth nerve palsy, are at increased risk for PIH.

Positive guaiac and bloody stool are poor predictors of intussusception

Abstract Background: Diagnostic error can lead to increased morbidity, mortality, healthcare utilization and cost. The 2015 National Academy of Medicine report “Improving Diagnosis in Healthcare” called for improving diagnostic accuracy by developing innovative electronic approaches to reduce medical errors, including missed or delayed diagnosis. The objective of this article was to develop a process to detect potential diagnostic discrepancy between pediatric emergency and inpatient discharge diagnosis using a computer-based tool facilitating expert review. Methods: Using a literature search and expert opinion, we identified 10 pediatric diagnoses with potential for serious consequences if missed or delayed. We then developed and applied a computerized tool to identify linked emergency department (ED) encounters and hospitalizations with these discharge diagnoses. The tool identified discordance between ED and hospital discharge diagnoses. Cases identified as discordant were manually reviewed by pediatric emergency medicine experts to confirm discordance. Results: Our computerized tool identified 55,233 ED encounters for hospitalized children over a 5-year period, of which 2161 (3.9%) had one of the 10 selected high-risk diagnoses. After expert record review, we identified 67 (3.1%) cases with discordance between ED and hospital discharge diagnoses. The most common discordant diagnoses were Kawasaki disease and pancreatitis. Conclusions: We successfully developed and applied a semi-automated process to screen a large volume of hospital encounters to identify discordant diagnoses for selected pediatric medical conditions. This process may be valuable for informing and improving ED diagnostic accuracy.

Diagnostic Lumbar Puncture Among Children With Facial Palsy in a Lyme Disease Endemic Area

Background Currant jelly stool is a late manifestation of intussusception and is rarely seen in clinical practice. Other forms of GI bleeding have not been thoroughly studied and little is known about their respective diagnostic values. Objective To assess the predictive value of GI bleeding (positive guaiac test, bloody stool and rectal bleeding in evaluation of intussusception. Methods We performed a retrospective cross‐sectional study cohort of all children, ages 1 month‐6 years of age, who had an abdominal ultrasound obtained evaluating for intussusception over 5 year period. We identified intussusception if diagnosed by ultrasound, air‐contrast enema or surgery. Univariate and a multivariate logistic regression analysis were performed. Results During the study period 1258 cases met the study criteria; median age was 1.7 years (IQR 0.8, 2.9) and 37% were females. Overall 176 children had intussusception; 153 (87%) were ileo‐colic and 23 were ileo‐ileal. Univariate risk ratio and adjusted Odds ratio were 1.3 (95% CI, 0.8, 2.0) and 1.3 (0.7, 2.4) for positive guaiac test, 1.1 (0.6, 2.1) and 0.9 (0.3, 3.0) for bloody stool, and 1.7 (1.02, 2.8) and 1.3 (0.5, 3.1) for rectal bleeding. Conclusion Blood in stool, whether visible or tested by guaiac test has poor diagnostic performance in the evaluation of intussusception and is not independently predictive of intussusception. If the sole purpose of a rectal exam in these patients is for guaiac testing it should be reconsidered.