Uli K. Chettipally

Immediate and Delayed Traumatic Intracranial Hemorrhage in Patients With Head Trauma and Preinjury Warfarin or Clopidogrel Use

STUDY OBJECTIVE Patients receiving warfarin or clopidogrel are considered at increased risk for traumatic intracranial hemorrhage after blunt head trauma. The prevalence of immediate traumatic intracranial hemorrhage and the cumulative incidence of delayed traumatic intracranial hemorrhage in these patients, however, are unknown. The objective of this study is to address these gaps in knowledge. METHODS A prospective, observational study at 2 trauma centers and 4 community hospitals enrolled emergency department (ED) patients with blunt head trauma and preinjury warfarin or clopidogrel use from April 2009 through January 2011. Patients were followed for 2 weeks. The prevalence of immediate traumatic intracranial hemorrhage and the cumulative incidence of delayed traumatic intracranial hemorrhage were calculated from patients who received initial cranial computed tomography (CT) in the ED. Delayed traumatic intracranial hemorrhage was defined as traumatic intracranial hemorrhage within 2 weeks after an initially normal CT scan result and in the absence of repeated head trauma. RESULTS A total of 1,064 patients were enrolled (768 warfarin patients [72.2%] and 296 clopidogrel patients [27.8%]). There were 364 patients (34.2%) from Level I or II trauma centers and 700 patients (65.8%) from community hospitals. One thousand patients received a cranial CT scan in the ED. Both warfarin and clopidogrel groups had similar demographic and clinical characteristics, although concomitant aspirin use was more prevalent among patients receiving clopidogrel. The prevalence of immediate traumatic intracranial hemorrhage was higher in patients receiving clopidogrel (33/276, 12.0%; 95% confidence interval [CI] 8.4% to 16.4%) than patients receiving warfarin (37/724, 5.1%; 95% CI 3.6% to 7.0%), relative risk 2.31 (95% CI 1.48 to 3.63). Delayed traumatic intracranial hemorrhage was identified in 4 of 687 (0.6%; 95% CI 0.2% to 1.5%) patients receiving warfarin and 0 of 243 (0%; 95% CI 0% to 1.5%) patients receiving clopidogrel. CONCLUSION Although there may be unmeasured confounders that limit intergroup comparison, patients receiving clopidogrel have a significantly higher prevalence of immediate traumatic intracranial hemorrhage compared with patients receiving warfarin. Delayed traumatic intracranial hemorrhage is rare and occurred only in patients receiving warfarin. Discharging patients receiving anticoagulant or antiplatelet medications from the ED after a normal cranial CT scan result is reasonable, but appropriate instructions are required because delayed traumatic intracranial hemorrhage may occur.

Risk of Traumatic Intracranial Hemorrhage in Patients with Head Injury and Preinjury Warfarin or Clopidogrel Use

OBJECTIVES Appropriate use of cranial computed tomography (CT) scanning in patients with mild blunt head trauma and preinjury anticoagulant or antiplatelet use is unknown. The objectives of this study were: 1) to identify risk factors for immediate traumatic intracranial hemorrhage (tICH) in patients with mild head trauma and preinjury warfarin or clopidogrel use and 2) to derive a clinical prediction rule to identify patients at low risk for immediate tICH. METHODS This was a prospective, observational study at two trauma centers and four community hospitals that enrolled adult emergency department (ED) patients with mild blunt head trauma (initial ED Glasgow Coma Scale [GCS] score 13 to 15) and preinjury warfarin or clopidogrel use. The primary outcome measure was immediate tICH, defined as the presence of ICH or contusion on the initial cranial CT. Risk for immediate tICH was analyzed in 11 independent predictor variables. Clinical prediction rules were derived with both binary recursive partitioning and multivariable logistic regression. RESULTS A total of 982 patients with a mean (± standard deviation [SD]) age of 75.4 (±12.6) years were included in the analysis. Sixty patients (6.1%; 95% confidence interval [CI] = 4.7% to 7.8%) had immediate tICH. History of vomiting (relative risk [RR] = 3.53; 95% CI = 1.80 to 6.94), abnormal mental status (RR = 2.85; 95% CI = 1.65 to 4.92), clopidogrel use (RR = 2.52; 95% CI = 1.55 to 4.10), and headache (RR = 1.81; 95% CI = 1.11 to 2.96) were associated with an increased risk for immediate tICH. Both binary recursive partitioning and multivariable logistic regression were unable to derive a clinical prediction model that identified a subset of patients at low risk for immediate tICH. CONCLUSIONS While several risk factors for immediate tICH were identified, the authors were unable to identify a subset of patients with mild head trauma and preinjury warfarin or clopidogrel use who are at low risk for immediate tICH. Thus, the recommendation is for urgent and liberal cranial CT imaging in this patient population, even in the absence of clinical findings.

A computational approach to early sepsis detection

OBJECTIVE To develop high-performance early sepsis prediction technology for the general patient population. METHODS Retrospective analysis of adult patients admitted to the intensive care unit (from the MIMIC II dataset) who were not septic at the time of admission. RESULTS A sepsis early warning algorithm, InSight, was developed and applied to the prediction of sepsis up to three hours prior to a patients first five hour Systemic Inflammatory Response Syndrome (SIRS) episode. When applied to a never-before-seen set of test patients, InSight predictions demonstrated a sensitivity of 0.90 (95% CI: 0.89-0.91) and a specificity of 0.81 (95% CI: 0.80-0.82), exceeding or rivaling that of existing biomarker detection methods. Across predictive times up to three hours before a sustained SIRS event, InSight maintained an average area under the ROC curve of 0.83 (95% CI: 0.80-0.86). Analysis of patient sepsis risk showed that contributions from the coevolution of multiple risk factors were more important than the contributions from isolated individual risk factors when making predictions further in advance. CONCLUSIONS Sepsis can be predicted at least three hours in advance of onset of the first five hour SIRS episode, using only nine commonly available vital signs, with better performance than methods in standard practice today. High-order correlations of vital sign measurements are key to this prediction, which improves the likelihood of early identification of at-risk patients.

Emergency Physicians’ Knowledge and Attitudes of Clinical Decision Support in the Electronic Health Record: A Survey‐based Study

OBJECTIVES The objective was to investigate clinician knowledge of and attitudes toward clinical decision support (CDS) and its incorporation into the electronic health record (EHR). METHODS This was an electronic survey of emergency physicians (EPs) within an integrated health care delivery system that uses a complete EHR. Randomly assigned respondents completed one of two questionnaires, both including a hypothetical vignette and self-reported knowledge of and attitudes about CDS. One vignette version included CDS, and the other did not (NCDS). The vignette described a scenario in which a cranial computed tomography (CCT) is not recommended by validated prediction rules (the Pediatric Emergency Care Applied Research Network [PECARN] rules). In both survey versions, subjects responded first with their likely approach to evaluation and then again after receiving either CDS (the PECARN prediction rules) or no additional support. Descriptive statistics were used for self-reported responses and multivariate logistic regression was used to identify predictors of self-reported knowledge and use of the PECARN rules, as well as use of vignette responses. RESULTS There were 339 respondents (68% response rate), with 172 of 339 (51%) randomized to the CDS version. Initially, 25% of respondents to each version indicated they would order CCTs. After CDS, 30 of 43 (70%) of respondents who initially would order CCTs changed their management decisions to no CCT versus two of 41 (5%) with the NCDS version (chi-square, p = 0.003). In response to self-report questions, 81 of 338 respondents (24%) reported having never heard of the PECARN prediction rules, 122 of 338 (36%) were aware of the rules but not their specifics, and 135 of 338 (40%) reported knowing the rules and their specifics. Respondents agreed with favorable statements about CDS (75% to 96% agreement across seven statements) and approaches to its implementation into the EHR (60% to 93% agreement across seven statements). In multivariable analyses, EPs with tenure of 5 to 14 years (odds ratio [AOR] = 0.51, 95% confidence interval [CI] = 0.30 to 0.86) and for 15 years or more (AOR = 0.37, 95% CI = 0.20 to 0.70) were significantly less likely to report knowing the specifics of the PECARN prediction rules compared with EPs who practiced for fewer than 5 years. In addition, in the initial vignette responses (across both versions), physicians with ≥15 years of ED tenure compared to those with fewer than 5 years of experience (AOR = 0.30, 95% CI = 0.13 to 0.69), and those reporting knowing the specifics of the PECARN prediction rules were less likely to order CCTs (AOR = 0.53, 95% CI = 0.30 to 0.92). CONCLUSIONS EPs incorporated pediatric head trauma CDS via the EHR into their clinical judgment in a hypothetical scenario and reported favorable opinions of CDS in general and their inclusion into the EHR.

Discharge recommendation based on a novel technique of homeostatic analysis

Objective: We propose a computational framework for integrating diverse patient measurements into an aggregate health score and applying it to patient stability prediction. Materials and Methods: We mapped retrospective patient data from the Multiparameter Intelligent Monitoring in Intensive Care (MIMIC) II clinical database into a discrete multidimensional space, which was searched for measurement combinations and trends relevant to patient outcomes of interest. Patient trajectories through this space were then used to make outcome predictions. As a case study, we built AutoTriage, a patient stability prediction tool to be used for discharge recommendation. Results: AutoTriage correctly identified 3 times as many stabilizing patients as existing tools and achieved an accuracy of 92.9% (95% CI: 91.6–93.9%), while maintaining 94.5% specificity. Analysis of AutoTriage parameters revealed that interdependencies between risk factors comprised the majority of each patient stability score. Discussion: AutoTriage demonstrated an improvement in the sensitivity of existing stability prediction tools, while considering patient safety upon discharge. The relative contributions of risk factors indicated that time-series trends and measurement interdependencies are most important to stability prediction. Conclusion: Our results motivate the application of multidimensional analysis to other clinical problems and highlight the importance of risk factor trends and interdependencies in outcome prediction.

High-performance detection and early prediction of septic shock for alcohol-use disorder patients

Background The presence of Alcohol Use Disorder (AUD) complicates the medical conditions of patients and increases the difficulty of detecting and predicting the onset of septic shock for patients in the ICU. Methods We have developed a high-performance sepsis prediction algorithm, InSight, which outperforms existing methods for AUD patient populations. InSight analyses a combination of singlets, doublets, and triplets of clinical measurements over time to generate a septic shock risk score. AUD patients obtained from the MIMIC III database were used in this retrospective study to train InSight and compare performance with the Modified Early Warning Score (MEWS), the Simplified Acute Physiology Score (SAPS II), and the Systemic Inflammatory Response Syndrome (SIRS) for septic shock prediction and detection. Results From 4-fold cross validation, InSight performs particularly well on diagnostic odds ratio and demonstrates a relatively high Area Under the Receiver Operating Characteristic (AUROC) metric. Four hours prior to onset, InSight had an average AUROC of 0.815, and at the time of onset, InSight had an average AUROC value of 0.965. When applied to patient populations where AUD may complicate prediction methods of sepsis, InSight outperforms existing diagnostic tools. Conclusions Analysis of the higher order correlations and trends between relevant clinical measurements using the InSight algorithm leads to more accurate detection and prediction of septic shock, even in cases where diagnosis may be confounded by AUD.

Bleeding complications of central venous catheterization in septic patients with abnormal hemostasis.

OBJECTIVES Central venous catheterization (CVC) is thought to be relatively contraindicated in patients with thrombocytopenia or coagulopathy. We measured the 24-hour incidence of bleeding in septic emergency department (ED) patients undergoing CVC. METHODS This multicenter, retrospective cohort study included septic ED patients undergoing CVC with one of the following: platelets less than 100,000/μL, international normalized ratio at least 1.3, or partial thromboplastin time at least 35 seconds. Major bleeding included radiographically confirmed intrathoracic, mediastinal, or internal neck hemorrhage or line-related bleeding causing hemodynamic compromise. Minor bleeding included local oozing or superficial hematoma. Multivariable regression analysis was performed to determine the association between candidate variables and hemorrhagic complications. RESULTS Of the 936 cases, mean age was 68.1 years; 535 (57.2%) were male. Two or more qualifying laboratory abnormalities were present in 204 cases (21.8%). The proceduralists were predominately attendings (790; 84.4%). The initial veins were the internal jugular (n = 800; 85.5%), subclavian (n = 123; 13.1%), and femoral (n = 13; 1.4%). Initial access was successful in 872 cases (93.2%). We found one case (95% upper confidence limit: 0.6%) of major bleeding and 37 cases (4.0%; 95% confidence interval [CI], 2.8%-5.4%) of minor bleeding. Only failed access at the initial site was independently associated with hemorrhagic outcomes: adjusted odds ratio 8.2 (95% CI, 3.7-18.0). CONCLUSIONS Major bleeding from CVC in ED patients with abnormal hemostasis is rare. Minor bleeding is uncommon and infrequently requires intervention. Successful catheterization on the initial attempt is associated with fewer hemorrhagic complications. These results can inform the risk/benefit calculus for CVC in this population.

Using electronic health record collected clinical variables to predict medical intensive care unit mortality

Background Clinical decision support systems are used to help predict patient stability and mortality in the Intensive Care Unit (ICU). Accurate patient information can assist clinicians with patient management and in allocating finite resources. However, systems currently in common use have limited predictive value in the clinical setting. The increasing availability of Electronic Health Records (EHR) provides an opportunity to use medical information for more accurate patient stability and mortality prediction in the ICU. Objective Develop and evaluate an algorithm which more accurately predicts patient mortality in the ICU, using the correlations between widely available clinical variables from the EHR. Methods We have developed an algorithm, AutoTriage, which uses eight common clinical variables from the EHR to assign patient mortality risk scores. Each clinical variable produces a subscore, and combinations of two or three discretized clinical variables also produce subscores. A combination of weighted subscores produces the overall score. We validated the performance of this algorithm in a retrospective study on the MIMIC III medical ICU dataset. Results AutoTriage 12 h mortality prediction yields an Area Under Receiver Operating Characteristic value of 0.88 (95% confidence interval 0.86 to 0.88). At a sensitivity of 80%, AutoTriage maintains a specificity of 81% with a diagnostic odds ratio of 16.26. Conclusions Through the multidimensional analysis of the correlations between eight common clinical variables, AutoTriage provides an improvement in the specificity and sensitivity of patient mortality prediction over existing prediction methods.

Does primary stroke center certification change ED diagnosis, utilization, and disposition of patients with acute stroke?

BACKGROUND AND PURPOSE We examined the impact of primary stroke center (PSC) certification on emergency department (ED) use and outcomes within an integrated delivery system in which EDs underwent staggered certification. METHODS A retrospective cohort study of 30,461 patients seen in 17 integrated delivery system EDs with a primary diagnosis of transient ischemic attack (TIA), intracranial hemorrhage, or ischemic stroke between 2005 and 2008 was conducted. We compared ED stroke patient visits across hospitals for (1) temporal trends and (2) pre- and post-PSC certification-using logistic and linear regression models to adjust for comorbidities, patient characteristics, and calendar time, to examine major outcomes (ED throughput time, hospital admission, radiographic imaging utilization and throughput, and mortality) across certification stages. RESULTS There were 15,687 precertification ED visits and 11,040 postcertification visits. Primary stroke center certification was associated with significant changes in care processes associated with PSC certification process, including (1) ED throughput for patients with intracranial hemorrhage (55 minutes faster), (2) increased utilization of cranial magnetic resonance imaging for patients with ischemic stroke (odds ratio, 1.88; 95% confidence interval, 1.36-2.60), and (3) decrease in time to radiographic imaging for most modalities, including cranial computed tomography done within 6 hours of ED arrival (TIA: 12 minutes faster, ischemic stroke: 11 minutes faster), magnetic resonance imaging for patients with ischemic stroke (197 minutes faster), and carotid Doppler sonography for TIA patients (138 minutes faster). There were no significant changes in survival. CONCLUSIONS Stroke center certification was associated with significant changes in ED admission and radiographic utilization patterns, without measurable improvements in survival.

Use of Traumatic Brain Injury Prediction Rules With Clinical Decision Support

The investigators provide data from a multicenter trial regarding whether implementation of prediction rules safely decreases computed tomography use in children with minor head trauma. OBJECTIVES: We determined whether implementing the Pediatric Emergency Care Applied Research Network (PECARN) traumatic brain injury (TBI) prediction rules and providing risks of clinically important TBIs (ciTBIs) with computerized clinical decision support (CDS) reduces computed tomography (CT) use for children with minor head trauma. METHODS: Nonrandomized trial with concurrent controls at 5 pediatric emergency departments (PEDs) and 8 general EDs (GEDs) between November 2011 and June 2014. Patients were <18 years old with minor blunt head trauma. Intervention sites received CDS with CT recommendations and risks of ciTBI, both for patients at very low risk of ciTBI (no Pediatric Emergency Care Applied Research Network rule factors) and those not at very low risk. The primary outcome was the rate of CT, analyzed by site, controlling for time trend. RESULTS: We analyzed 16 635 intervention and 2394 control patients. Adjusted for time trends, CT rates decreased significantly (P < .05) but modestly (2.3%–3.7%) at 2 of 4 intervention PEDs for children at very low risk. The other 2 PEDs had small (0.8%–1.5%) nonsignificant decreases. CT rates did not decrease consistently at the intervention GEDs, with low baseline CT rates (2.1%–4.0%) in those at very low risk. The control PED had little change in CT use in similar children (from 1.6% to 2.9%); the control GED showed a decrease in the CT rate (from 7.1% to 2.6%). For all children with minor head trauma, intervention sites had small decreases in CT rates (1.7%–6.2%). CONCLUSIONS: The implementation of TBI prediction rules and provision of risks of ciTBIs by using CDS was associated with modest, safe, but variable decreases in CT use. However, some secular trends were also noted.