John S. Garrett M.D.

Dixon, A.L., McCully, B.H., Rick, E.A., Dewey, E., Farrell, D.H., Morrison, L.J., McMullan, J., Robinson, B.R.H., Callum, J., Tibbs, B., Dries, D.J., Jui, J., Gandhi, R.R., Garrett, J.S., Weisfeldt, M.L., Wade, C.E., Aufderheide, T.P., Frascone, R.J., Tallon, J.M., Kannas, D., Williams, C., Rowell, S.E., Schreiber, M.A., McKnight, B., Meier, E.N., May, S., Sheehan, K., Bulger, E.M., Idris, A.H., Christenson, J., Bosarge, P.L., Colella, M.R., Johannigman, J., Cotton, B.A., Richmond, N.J., Zielinski, M.D., Schlamp, R., Klein, L., Rizoli, S., Gamber, M., Fleming, M., Hwang, J., Vincent, L.E., Hendrickson, A., Simonson, R., Klotz, P., Ferrara, M., Sopko, G. and Witham, W. (2020). “TXA Administration in the Field Does Not Affect Admission TEG after Traumatic Brain Injury.” J Trauma Acute Care Surg Aug 28. [Epub ahead of print.].

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BACKGROUND: No FDA-approved medication improves outcomes following traumatic brain injury (TBI). A forthcoming clinical trial that evaluated the effects of two prehospital tranexamic acid (TXA) dosing strategies compared with placebo demonstrated no differences in thromboelastography (TEG) values. We proposed to explore the impact of TXA on markers of coagulation and fibrinolysis in patients with moderate to severe TBI. METHODS: Data were extracted from a placebo-controlled clinical trial in which patients ≥15 years old with TBI (Glascow Coma Scale 3-12) and systolic blood pressure ≥90 mmHg were randomized prehospital to receive placebo bolus/placebo infusion (Placebo), 1 gram (g) TXA bolus/1g TXA infusion (Bolus Maintenance [BM]); or 2g TXA bolus/placebo infusion (Bolus Only [BO]). TEG was performed and coagulation measures including prothrombin time (PT), activated partial thromboplastin time (aPTT), international ratio (INR), fibrinogen, D-dimer, plasmin anti-plasmin (PAP), thrombin anti-thrombin (TAT), tissue plasminogen activator (tPA), and plasminogen activator inhibitor-1 (PAI-1) were quantified at admission and six hours later. RESULTS: Of 966 patients receiving study drug, 700 had labs drawn at admission and six hours later. There were no statistically significant differences in TEG values, including LY30, between groups (p>0.05). No differences between PT, aPTT, INR, fibrinogen, TAT, tPA, and PAI-1 were demonstrated across treatment groups. Concentrations of D-dimer in TXA treatment groups were less than placebo at six hours (p<0.001). Concentrations of PAP were less in TXA treatment groups than placebo on admission (p<0.001) and six hours (p=0.02). No differences in D-dimer and PAP were observed between BM and BO. CONCLUSION: While D-dimer and PAP levels reflect a lower degree of fibrinolysis following prehospital administration of TXA when compared to placebo in a large prehospital trial of patients with TBI, TEG obtained on admission and six hours later did not demonstrate any differences in fibrinolysis between the two TXA dosing regimens and placebo. LEVEL OF EVIDENCE: III; Diagnostic.

Kline, J. A., J. S. Garrett, E. J. Sarmiento, C. C. Strachan and D. M. Courtney (2020). “Over-Testing for Suspected Pulmonary Embolism in American Emergency Departments: The Continuing Epidemic.” Circ Cardiovasc Qual Outcomes Jan 20. [Epub ahead of print]

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BACKGROUND: No recent data have investigated rates of diagnostic testing for pulmonary embolism (PE) in US emergency departments (EDs), and no data have examined computed tomographic pulmonary angiography (CTPA) rates in subgroups at high risk for adverse imaging outcomes, including young women and children. We hypothesized that over-testing for PE remains a problem. METHODS AND RESULTS: We used electronic health record and billing data for 16 EDs in Indiana and 11 hospitals in the Dallas-Fort Worth area from 2016 to 2019 to locate ED patients who had any of the following: D-dimer, CTPA, scintillation ventilation perfusion lung scanning or formal pulmonary angiography. The primary outcomes were ED encounter volume-adjusted CTPA rate, PE yield rate with subgroup reporting for children (<18 years) and women under 45 years. We also examined the most frequent diagnoses. From a total visit volume of 1 828 010 patient encounters, 97 125 (5.3% of the total volume) had a diagnostic test for PE, including 25 870 patients who had CTPA order without D-dimer (59% of all tests for PE). The yield rate for PE from CTPA scans was 1.3% (1.1%-1.5%) in Indiana and 4.8% (4.2%-5.1%) in Dallas-Fort Worth (pooled rate 3.1%). Linear regression showed that increased D-dimer ordering correlated with increased PE yield rate (Pearson's R(2)=0.43; P<0.001). From the pooled sample, 59% of CTPAs done were in women, with 21% of all CTPAs performed on women under 45 years of age, and 1.4% (1.3%-1.5%) on children. The most frequent diagnoses were symptom-based descriptions of chest pain (34%) and shortness of breath (6.5%) and the condition-based diagnosis of pneumonia (4.1%). CONCLUSIONS: Over-testing for PE in American EDs remains a major public health problem. Centers with higher D-dimer ordering had higher yield of PE on CTPA. These data suggest the potential for implementation of D-dimer based protocols to reduce low-yield CTPA ordering.

Michelson, E., J. S. Huff, J. Garrett and R. Naunheim (2019). “Triage of Mild Head-Injured Intoxicated Patients Could Be Aided by Use of an Electroencephalogram-Based Biomarker.” J Neurosci Nurs 51(2): 62-66.

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OBJECTIVE: Drug and alcohol (DA)-related emergency department (ED) visits represent an increasing fraction the head-injured population seen in the ED. Such patients present a challenge to the evaluation of head injury and determination of need for computed tomographic (CT) scan and further clinical path. This effort examined whether an electroencephalogram (EEG)-based biomarker could aid in reducing unnecessary CT scans in the intoxicated ED population. METHOD: This is a retrospective secondary study of an independent prospective US Food and Drug Administration validation trial that demonstrated the efficacy of (1) an automatic Structural Injury Classifier for the likelihood of injury visible on a CT (CT+) and (2) an EEG-based Brain Function Index to assess functional impairment in minimally impaired, head-injured adults presenting within 3 days of injury. Impact on the biomarker performance in patients who presented with or without DA was studied. RESULTS: Structural Injury Classifier sensitivity was not significantly impacted by the presence of DA. Although specificity decreased, it remained several times higher than obtained using standard CT decision rules. Furthermore, the potential to reduce the number of unnecessary scans by approximately 30% was demonstrated when the Structural Injury Classifier was integrated into CT clinical triage. The Brain Function Index was demonstrated to be independent of the presence of DA. CONCLUSION: This EEG-based assessment technology used to identify the likelihood of structural or functional brain injury in mildly head-injured patients represents an objective way to aid in triage patients with DA on presentation, with the potential to decrease overscanning while not sacrificing sensitivity to injuries visible on CT.E

Michelson, E., J. S. Huff, J. Garrett and R. Naunheim (2019). “Triage of Mild Head-Injured Intoxicated Patients Could Be Aided by Use of an Electroencephalogram-Based Biomarker.” J Neurosci Nurs Jan 14. [Epub ahead of print].

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OBJECTIVE: Drug and alcohol (DA)-related emergency department (ED) visits represent an increasing fraction the head-injured population seen in the ED. Such patients present a challenge to the evaluation of head injury and determination of need for computed tomographic (CT) scan and further clinical path. This effort examined whether an electroencephalogram (EEG)-based biomarker could aid in reducing unnecessary CT scans in the intoxicated ED population. METHOD: This is a retrospective secondary study of an independent prospective US Food and Drug Administration validation trial that demonstrated the efficacy of (1) an automatic Structural Injury Classifier for the likelihood of injury visible on a CT (CT+) and (2) an EEG-based Brain Function Index to assess functional impairment in minimally impaired, head-injured adults presenting within 3 days of injury. Impact on the biomarker performance in patients who presented with or without DA was studied. RESULTS: Structural Injury Classifier sensitivity was not significantly impacted by the presence of DA. Although specificity decreased, it remained several times higher than obtained using standard CT decision rules. Furthermore, the potential to reduce the number of unnecessary scans by approximately 30% was demonstrated when the Structural Injury Classifier was integrated into CT clinical triage. The Brain Function Index was demonstrated to be independent of the presence of DA. CONCLUSION: This EEG-based assessment technology used to identify the likelihood of structural or functional brain injury in mildly head-injured patients represents an objective way to aid in triage patients with DA on presentation, with the potential to decrease overscanning while not sacrificing sensitivity to injuries visible on CT.

Garrett, J. S., C. Berry, H. Wong, H. Qin and J. A. Kline (2018). “The effect of vertical split-flow patient management on emergency department throughput and efficiency.” Am J Emerg Med 36(9): 1581-1584.

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BACKGROUND: To address emergency department overcrowding operational research seeks to identify efficient processes to optimize flow of patients through the emergency department. Vertical flow refers to the concept of utilizing and assigning patients virtual beds rather than to an actual physical space within the emergency department to care of low acuity patients. The aim of this study is to evaluate the impact of vertical flow upon emergency department efficiency and patient satisfaction. METHODS: Prospective pre/post-interventional cohort study of all intend-to-treat patients presenting to the emergency department during a two-year period before and after the implementation of a vertical flow model. RESULTS: In total 222,713 patient visits were included in the analysis with 107,217 patients presenting within the pre-intervention and 115,496 in the post-intervention groups. The results of the regression analysis demonstrate an improvement in throughput across the entire ED patient population, decreasing door to departure time by 17min (95% CI 15-18) despite an increase in patient volume. No statistically significant difference in patient satisfaction scores were found between the pre- and post-intervention. CONCLUSIONS: Initiation of a vertical split flow model was associated with improved ED efficiency.