Publications

2010

Leffler, Daniel A, Rakhi Kheraj, Sagar Garud, Naama Neeman, Larry A Nathanson, Ciaran P Kelly, Mandeep Sawhney, et al. (2010) 2010. “The Incidence and Cost of Unexpected Hospital Use After Scheduled Outpatient Endoscopy.”. Archives of Internal Medicine 170 (19): 1752-7. https://doi.org/10.1001/archinternmed.2010.373.

BACKGROUND: Data on complications of gastrointestinal endoscopic procedures are limited. We evaluated prospectively the incidence and cost of hospital visits resulting from outpatient endoscopy.

METHODS: We developed an electronic medical record-based system to record automatically admissions to the emergency department (ED) within 14 days after endoscopy. Physicians evaluated all reported cases for relatedness of the ED visit to the prior endoscopy based on predetermined criteria.

RESULTS: We evaluated 6383 esophagogastroduodenoscopies (EGDs) and 11 632 colonoscopies (7392 for screening and surveillance). Among these, 419 ED visits and 266 hospitalizations occurred within 14 days after the procedure. One hundred thirty-four (32%) of the ED visits and 76 (29%) of the hospitalizations were procedure related, whereas 31 complications were recorded by standard physician reporting (P < .001). Procedure-related hospital visits occurred in 1.07%, 0.84%, and 0.95% of all EGDs, all colonoscopies, and screening colonoscopies, respectively. The mean costs were $1403 per ED visit and $10 123 per hospitalization based on Medicare standardized rates. Across the overall screening/surveillance colonoscopy program, these episodes added $48 per examination.

CONCLUSIONS: Using a novel automated system, we observed a 1% incidence of related hospital visits within 14 days of outpatient endoscopy, 2- to 3-fold higher than recent estimates. Most events were not captured by standard reporting, and strategies for automating adverse event reporting should be developed. The cost of unexpected hospital visits postendoscopy may be significant and should be taken into account in screening or surveillance programs.

Ganz, Aura, Xunyi Yu, James Schafer, Sophie D’Hauwe, Larry A Nathanson, Jonathan Burstein, Gregory R Ciottone, and Graydon Lord. (2010) 2010. “DIORAMA: Dynamic Information Collection and Resource Tracking Architecture.”. Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference 2010: 386-9. https://doi.org/10.1109/IEMBS.2010.5628007.

DIORAMA is a real-time scalable decision support framework built on rapid information collection and accurate resource tracking functionalities. Using RFID technology the proposed system tracks emergency responders and victims at the disaster scene. DIORAMA improves the accuracy and decreases the time it takes rescuers to triage, treat and evacuate victims from a disaster scene, as compared to the traditional methods and process that involves using paper triage tags. The information can then be viewed from a website that shows a satellite image of the disaster area with icons representing the paramedics and victims.

Kaji, Amy H, Roger J Lewis, Tony Beavers-May, Robert Berg, Eileen Bulger, Charles Cairns, Clifton Callaway, et al. (2010) 2010. “Summary of NIH Medical-Surgical Emergency Research Roundtable Held on April 30 to May 1, 2009.”. Annals of Emergency Medicine 56 (5): 522-37. https://doi.org/10.1016/j.annemergmed.2010.03.014.

STUDY OBJECTIVE: In 2003, the Institute of Medicine Committee on the Future of Emergency Care in the United States Health System convened and identified a crisis in emergency care in the United States, including a need to enhance the research base for emergency care. As a result, the National Institutes of Health (NIH) formed an NIH Task Force on Research in Emergency Medicine to enhance NIH support for emergency care research. Members of the NIH Task Force and academic leaders in emergency care participated in 3 roundtable discussions to prioritize current opportunities for enhancing and conducting emergency care research. The objectives of these discussions were to identify key research questions essential to advancing the scientific underpinnings of emergency care and to discuss the barriers and best means to advance research by exploring the role of research networks and collaboration between the NIH and the emergency care community.

METHODS: The Medical-Surgical Research Roundtable was convened on April 30 to May 1, 2009. Before the roundtable, the emergency care domains to be discussed were selected and experts in each of the fields were invited to participate in the roundtable. Domain experts were asked to identify research priorities and challenges and separate them into mechanistic, translational, and clinical categories. After the conference, the lists were circulated among the participants and revised to reach a consensus.

RESULTS: Emergency care research is characterized by focus on the timing, sequence, and time sensitivity of disease processes and treatment effects. Rapidly identifying the phenotype and genotype of patients manifesting a specific disease process and the mechanistic reasons for heterogeneity in outcome are important challenges in emergency care research. Other research priorities include the need to elucidate the timing, sequence, and duration of causal molecular and cellular events involved in time-critical illnesses and injuries, and the development of treatments capable of halting or reversing them; the need for novel animal models; and the need to understand why there are regional differences in outcome for the same disease processes. Important barriers to emergency care research include a limited number of trained investigators and experienced mentors, limited research infrastructure and support, and regulatory hurdles. The science of emergency care may be advanced by facilitating the following: (1) training emergency care investigators with research training programs; (2) developing emergency care clinical research networks; (3) integrating emergency care research into Clinical and Translational Science Awards; (4) developing emergency care-specific initiatives within the existing structure of NIH institutes and centers; (5) involving emergency specialists in grant review and research advisory processes; (6) supporting learn-phase or small, clinical trials; and (7) performing research to address ethical and regulatory issues.

CONCLUSION: Enhancing the research base supporting the care of medical and surgical emergencies will require progress in specific mechanistic, translational, and clinical domains; effective collaboration of academic investigators across traditional clinical and scientific boundaries; federal support of research in high-priority areas; and overcoming limitations in available infrastructure, research training, and access to patient populations.

Yuan, Weihong, Kelley E Deren, James P McAllister, Scott K Holland, Diana M Lindquist, Alessandro Cancelliere, Melissa Mason, et al. (2010) 2010. “Diffusion Tensor Imaging Correlates With Cytopathology in a Rat Model of Neonatal Hydrocephalus.”. Cerebrospinal Fluid Research 7: 19. https://doi.org/10.1186/1743-8454-7-19.

BACKGROUND: Diffusion tensor imaging (DTI) is a non-invasive MRI technique that has been used to quantify CNS abnormalities in various pathologic conditions. This study was designed to quantify the anisotropic diffusion properties in the brain of neonatal rats with hydrocephalus (HCP) and to investigate association between DTI measurements and cytopathology.

METHODS: DTI data were acquired between postnatal day 7 (P7) and P12 in 12 rats with HCP induced at P2 and in 15 age-matched controls. Animals were euthanized at P11 or P22/P23 and brains were processed with immunohistochemistry for glial fibrillary acidic protein (GFAP), ionized calcium-binding adaptor molecule (Iba-1), and luxol fast blue (LFB) to assess astrocytosis, microglial reactivity and degree of myelination, respectively.

RESULTS: Hydrocephalic rats were consistently found to have an abnormally low (at corrected p-level of <0.05) fractional anisotropy (FA) value and an abnormally high mean diffusivity (MD) value in the cerebral cortex (CX), the corpus callosum (CC), and the internal capsule (IC). Immunohistochemical analysis demonstrated trends of increasing astrocyte and microglial reactivity in HCP rats at P11 that reached statistical significance at P22/P23. A trend toward reduced myelination in the HCP rats was also found at P22/P23. Correlation analysis at P11 for the CC demonstrated statistically significant correlations (or trends) between the DTI measurement (the decreased FA and increased MD values) and the GFAP or Iba-1 rankings. The immunohistochemical rankings in the IC at P22/P23 were also significantly correlated or demonstrated a trend with both FA and MD values.

CONCLUSIONS: This study demonstrates the feasibility of employing DTI on the brain in experimental hydrocephalus in neonatal rats and reveals impairments in multiple regions of interest in both grey and white matter. A strong correlation was found between the immunohistochemical results and the changes in anisotropic diffusion properties.

Bair, Aaron E, Kalani Olmsted, Calvin A Brown, Tobias Barker, Daniel Pallin, and Ron M Walls. (2010) 2010. “Assessment of the Storz Video Macintosh Laryngoscope for Use in Difficult Airways: A Human Simulator Study.”. Academic Emergency Medicine : Official Journal of the Society for Academic Emergency Medicine 17 (10): 1134-7.

OBJECTIVES: Video laryngoscopy has been shown to improve glottic exposure when compared to direct laryngoscopy in operating room studies. However, its utility in the hands of emergency physicians (EPs) remains undefined. A simulated difficult airway was used to determine if intubation by EPs using a video Macintosh system resulted in an improved glottic view, was easier, was faster, or was more successful than conventional direct laryngoscopy.

METHODS: Emergency medicine (EM) residents and attending physicians at two academic institutions performed endotracheal intubation in one normal and two identical difficult airway scenarios. With the difficult scenarios, the participants used video laryngoscopy during the second case. Intubations were performed on a medium-fidelity human simulator. The difficult scenario was created by limiting cervical spine mobility and inducing trismus. The primary outcome was the proportion of direct versus video intubations with a grade I or II Cormack-Lehane glottic view. Ease of intubation (self-reported via 10-cm visual analog scale [VAS]), time to intubation, and success rate were also recorded. Descriptive statistics as well as medians with interquartile ranges (IQRs) are reported where appropriate. The Wilcoxon matched pairs signed-rank test was used for comparison testing of nonparametric data.

RESULTS: Participants (n = 39) were residents (59%) and faculty. All had human intubation experience; 51% reported more than 100 prior intubations. On difficult laryngoscopy, a Cormack-Lehane grade I or II view was obtained in 20 (51%) direct laryngoscopies versus 38 (97%) of the video-assisted laryngoscopies (p < 0.01). The median VAS score for difficult airways was 50 mm (IQR = 28–73 mm) for direct versus 18 mm (IQR = 9–50 mm) for video (p < 0.01). The median time to intubation in difficult airways was 25 seconds (IQR = 16–44 seconds) for direct versus 20 seconds (IQR = 12–35 seconds) for video laryngoscopy (p < 0.01). All intubations were successful without need for an invasive airway.

CONCLUSIONS: In this simulation, video laryngoscopy was associated with improved glottic exposure, was perceived as easier, and was slightly faster than conventional direct laryngoscopy in a simulated difficult airway. Absence of secretions and blood limits the generalizability of our findings; human studies are needed.

Brown, Calvin A, Aaron E Bair, Daniel J Pallin, Erik G Laurin, Ron M Walls, and National Emergency Airway Registry Investigators. (2010) 2010. “Improved Glottic Exposure With the Video Macintosh Laryngoscope in Adult Emergency Department Tracheal Intubations.”. Annals of Emergency Medicine 56 (2): 83-8. https://doi.org/10.1016/j.annemergmed.2010.01.033.

STUDY OBJECTIVE: Glottic visualization with video is superior to direct laryngoscopy in controlled operating room studies. However, glottic exposure with video laryngoscopy has not been evaluated in the emergency department (ED) setting, where blood, secretions, poor patient positioning, and physiologic derangement can complicate laryngoscopy. We measure the difference in glottic visualization with video versus direct laryngoscopy.

METHODS: We prospectively studied a convenience sample of tracheal intubations at 2 academic EDs. We performed laryngoscopy with the Karl Storz Video Macintosh Laryngoscope, which can be used for conventional direct laryngoscopy, as well as video laryngoscopy. We rated glottic visualization with the Cormack-Lehane (C-L) Scale, defining "good" visualization as C-L I or II and "poor" visualization as C-L III or IV. We compared glottic exposure between direct and video laryngoscopy, determining the proportion of poor direct visualizations improved to good visualization with video laryngoscopy. We also determined the proportion of good direct visualizations worsened to poor visualization by video laryngoscopy.

RESULTS: We report data on 198 patients, including 146 (74%) medical, 51 (26%) trauma, and 1 (0.51%) unknown indications. All were tracheally intubated by emergency physicians. Postgraduate year 3 or 4 residents performed 102 (52.3%) of the laryngoscopies, postgraduate year 2 residents performed 60 (30.8%), interns performed 20 (10.3%), attending physicians performed 9 (4.6%), and operator experience and specialty were not reported in 4. Overall, good visualization (C-L grade I or II) was attained in 158 direct (80%) versus 185 video laryngoscopies (93%; McNemar's P<.0001). Of the 40 patients with poor glottic exposure on direct laryngoscopy, video laryngoscopy improved the view in 31 (78%; 95% confidence interval 62% to 89%). Of the 158 patients with good glottic view on direct laryngoscopy, video laryngoscopy worsened the view in 4 (3%; 95% confidence interval 0.7% to 6%).

CONCLUSION: Video laryngoscopy affords more grade I and II views than direct laryngoscopy and improves glottic exposure in most patients with poor direct glottic visualization. In a small proportion of cases, glottic exposure is worse with video than direct laryngoscopy.

2009

Yli-Hietanen, Jari, Samuli Niiranen, Michael Aswell, and Larry Nathanson. (2009) 2009. “Domain-Specific Analytical Language Modeling–the Chief Complaint As a Case Study.”. International Journal of Medical Informatics 78 (12): e27-30. https://doi.org/10.1016/j.ijmedinf.2009.02.002.

PURPOSE: A large share of the information in electronic medical records (EMRs) consists of free-text compositions. From a computational point-of-view, the continuing prevalence of free-text entry is a major hindrance when the goal is to increase automation in EMRs. However, the efforts in developing standards for the structured representation of medical information have not proven to be a panacea. The information space of clinical medicine is very diverse and constantly evolving, making it challenging to develop standards for the domain. This paper reports a study aiming to increase automation in the EMR through the computational understanding of specific class of medical text in English, namely emergency department chief complaints.

METHODS: We apply domain-specific analytical modeling for the computational understanding of chief complaints. We evaluate the performance of this approach in the automatic classification of chief complaints, e.g., for use in automatic syndromic surveillance.

RESULTS: The evaluation in a multi-hospital setting showed that the presented algorithm was accurate in terms of classification correctness. Also, use of approximate matching in the algorithm to cope with typographic variance did not affect classification correctness while increasing classification completeness.

Berkman, Matthew, Jacob Ufberg, Larry A Nathanson, and Nathan I Shapiro. (2009) 2009. “Anion Gap As a Screening Tool for Elevated Lactate in Patients With an Increased Risk of Developing Sepsis in the Emergency Department.”. The Journal of Emergency Medicine 36 (4): 391-4. https://doi.org/10.1016/j.jemermed.2007.12.020.

OBJECTIVES: Serum lactate levels are a useful tool in monitoring critically ill patients, especially those who are septic. However, lactate levels are often not routinely drawn or rapidly available in some institutions. The objective of this study was to determine if a readily available anion gap (AG) could be used as a surrogate marker for abnormal lactate level in Emergency Department (ED) patients at risk for sepsis.

METHODS: Prospective, observational cohort study of consecutive ED patients seen at an urban university tertiary care referral center with 46,000 annual ED visits. ED patients aged 18 years or older presenting with clinically suspected infection were eligible for enrollment if a serum chemistry and lactate levels were drawn during the ED visit. During the 9-month study period, 1419 patients were enrolled. The initial basic chemistry panels, calculated AG, and lactate levels drawn in the ED were collected. We defined, a priori, an AG > 12 and a lactate > 4 mmol/L to be abnormal. Analysis was performed with Student's t-test, operating characteristics with 95% confidence intervals, and logistic regression.

RESULTS: The mean AG was 11.8 (SD 3.6) and the mean lactate was 2.1 (SD 1.3). For an AG > 12, the mean lactate was 2.9 (SD 1.7), compared with 1.8 (SD 0.8) for an AG < 12. The sensitivity of an elevated AG (> 12) in predicting elevated lactate levels (> 4 mmol/L) was 80% (72-87%) and the specificity was 69% (66-71%). Patients with a gap > 12 had a 7.3-fold (4.6-11.4) increased risk of having a lactate > 4 mmol/L. The area under the curve was 0.84.

CONCLUSION: This study suggests that an elevated AG obtained in the ED is a moderately sensitive and specific means to detect elevated lactate levels in ED patients at risk for sepsis. This information may be somewhat helpful to Emergency Physicians to risk-stratify their patients to provide more aggressive early resuscitation.

Gangavati, Anupama S, Dan K Kiely, Lara K Kulchycki, Richard E Wolfe, Lawrence Mottley, Sean P Kelly, Larry A Nathanson, Alan P Abrams, and Lewis A Lipsitz. (2009) 2009. “Prevalence and Characteristics of Traumatic Intracranial Hemorrhage in Elderly Fallers Presenting to the Emergency Department Without Focal Findings.”. Journal of the American Geriatrics Society 57 (8): 1470-4. https://doi.org/10.1111/j.1532-5415.2009.02344.x.

OBJECTIVES: To determine the prevalence and associated characteristics of traumatic intracranial hemorrhage (ICH) in elderly fallers presenting to the emergency department (ED) without focal findings.

DESIGN: Retrospective cohort study.

SETTING: University-affiliated teaching hospital ED.

PARTICIPANTS: Patients aged 65 and older presenting with a fall to the ED and undergoing a head computed tomography (CT) scan.

MEASUREMENTS: Electronic medical records and CT scans of 404 consecutive patients were reviewed. Characteristics of patients with and without ICH were compared using unadjusted analyses. Patients taking warfarin, aspirin, or clopidogrel alone or in combination were compared with those not taking these medications. Multivariate logistic regression analyses were performed to determine variables independently associated with ICH.

RESULTS: Forty-seven of 404 elderly fallers (11.6%) without focal findings had an ICH. Unadjusted analyses in these pilot data showed that warfarin was not significantly associated with ICH. Multivariate analyses indicated that elderly people living in at home were more likely to have ICH than those living in nursing homes or assisted living facilities (odds ratio (OR)=3.2, 95% confidence interval (CI)=1.30-8.13) and that those with head trauma were more likely to have ICH than those without (OR=3.9, 95% CI=1.25-7.80). Aspirin was found to be protective (OR=0.49, 95% CI=0.24-0.98).

CONCLUSION: ICH is common in elderly fallers presenting to the ED without focal findings. Anticoagulation alone did not appear to increase the risk of ICH, and aspirin was found to be protective, but prospective studies are needed to better assess this relationship.

2008

Niiranen, Samuli T, Jari M Yli-Hietanen, and Larry A Nathanson. (2008) 2008. “Toward Reflective Management of Emergency Department Chief Complaint Information.”. IEEE Transactions on Information Technology in Biomedicine : A Publication of the IEEE Engineering in Medicine and Biology Society 12 (6): 763-7. https://doi.org/10.1109/TITB.2008.926464.

An approach coined as "reflective information management" is presented as a technique for the management of emergency department chief complaint information. The architecture of a system integrating principles from this approach is described and its performance is evaluated in providing categorical information from free-text chief complaints for use, e.g., in automated syndromic surveillance.