Browsing by Author "McCarroll, Tyler"

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    Insights into the association between coagulopathy and inflammation: abnormal clot mechanics are a warning of immunologic dysregulation following major injury
    (AME, 2020-12) Savage, Stephanie A.; Zarzaur, Ben L.; Gaski, Greg E.; McCarroll, Tyler; Zamora, Ruben; Namas, Rami A.; Vodovotz, Yoram; Callcut, Rachael A.; Billiar, Timothy R.; McKinley, Todd O.; Orthopaedic Surgery, School of Medicine
    Background: Severe injury initiates a complex physiologic response encompassing multiple systems and varies phenotypically between patients. Trauma-induced coagulopathy may be an early warning of a poorly coordinated response at the molecular level, including a deleterious immunologic response and worsening of shock states. The onset of trauma-induced coagulopathy (TIC) may be subtle however. In previous work, we identified an early warning sign of coagulopathy from the admission thromboelastogram, called the MAR ratio. We hypothesized that a low MAR ratio would be associated with specific derangements in the inflammatory response. Methods: In this prospective, observational study, 88 blunt trauma patients admitted to the intensive care unit (ICU) were identified. Concentrations of inflammatory mediators were recorded serially over the course of a week and the MAR ratio was calculated from the admission thromboelastogram. Correlation analysis was used to assess the relationship between MAR and inflammatory mediators. Dynamic network analysis was used to assess coordination of immunologic response. Results: Seventy-nine percent of patients were male and mean age was 37 years (SD 12). The mean ISS was 30.2 (SD 12) and mortality was 7.2%. CRITICAL patients (MAR ratio ≤14.2) had statistically higher shock volumes at three time points in the first day compared to NORMAL patients (MAR ratio >14.2). CRITICAL patients had significant differences in IL-6 (P=0.0065), IL-8 (P=0.0115), IL-10 (P=0.0316) and MCP-1 (P=0.0039) concentrations compared to NORMAL. Differences in degree of expression and discoordination of immune response continued in CRITICAL patients throughout the first day. Conclusions: The admission MAR ratio may be the earliest warning signal of a pathologic inflammatory response associated with hypoperfusion and TIC. A low MAR ratio is an early indication of complicated dysfunction of multiple molecular processes following trauma.
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    SHOCK VOLUME: A PRECISION MEDICINE BASED INDEX THAT PREDICTS TRANSFUSION REQUIREMENTS AND ORGAN DYSFUNCTION IN MULTIPLY INJURED PATIENTS
    (Office of the Vice Chancellor for Research, 2016-04-08) McCarroll, Tyler; Metzger, Cameron; Bakdash, Kenaz; Gaski, Greg E.; McKinley, Todd O.
    Introduction: Multiply injured patients (MIPs) in hemorrhagic shock develop oxygen debt, which causes organ dysfunction and can lead to death. Clinicians monitor hypoperfusion by interpreting progression of traditional hemodynamic measures along with serum markers of hypoperfusion, which reflect current hemodynamic and metabolic status. However, these indices are sampled at discrete time points and poorly reflect cumulative hypoperfusion. Shock Volume (SV) is a novel, non-invasive, patient-specific index developed to quantify cumulative hypoperfusion. SV integrates the time and magnitude of shock index (Heart Rate/Systolic Blood Pressure) values above 0.9 (known threshold of hypoperfusion) using serial individual vital sign data. SV can be monitored in real time to assess ongoing hypoperfusion. The goal of this study was to determine how SV corresponded to transfusion requirements and organ dysfunction. Methods: SV was measured in six hour increments for 48 hours after injury in a retrospective cohort of 74 MIPs (18-65; Injury Severity Score > 18). SV was compared to base deficit (BD) in predicting mass transfusions (MT) and critical administration transfusions (CATs). Presence of multiple organ failure (MOF) was determined using the Denver Organ Failure assessment score, while Sequential Organ Failure Assessment scores were used to determine magnitude of organ dysfunction. Results: Patients who had accumulated 40 units of SV within six hours of injury and 100 units of SV within twelve hours of injury were at high risk for requiring MT or multiple CATs. SV measurements were equally sensitive and specific as compared to BD values in predicting transfusions. SV measurements at six hours after injury stratified patients at risk for MOF and corresponded to the magnitude of organ failure. Conclusions: SV is a patient-specific index that can be quantified in real-time in critically injured patients. SV is a non-invasive surrogate for cumulative hypoperfusion and predicts high volume transfusions and organ dysfunction.
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    Shock volume: Patient-specific cumulative hypoperfusion predicts organ dysfunction in a prospective cohort of multiply injured patients
    (Wolters Kluwer, 2018-07) McKinley, Todd O.; McCarroll, Tyler; Metzger, Cameron; Zarzaur, Ben L.; Savage, Stephanie A.; Bell, Teresa M.; Gaski, Greg E.; Orthopaedic Surgery, IU School of Medicine
    BACKGROUND: Multiply injured patients are at risk of developing hemorrhagic shock and organ dysfunction. We determined how cumulative hypoperfusion predicted organ dysfunction by integrating serial Shock Index measurements. METHODS: In this study, we calculated shock volume (SHVL) which is a patient-specific index that quantifies cumulative hypoperfusion by integrating abnormally elevated Shock Index (heart rate/systolic blood pressure ≥ 0.9) values acutely after injury. Shock volume was calculated at three hours (3 hr), six hours (6 hr), and twenty-four hours (24 hr) after injury. Organ dysfunction was quantified using Marshall Organ Dysfunction Scores averaged from days 2 through 5 after injury (aMODSD2–D5). Logistic regression was used to determine correspondence of 3hrSHVL, 6hrSHVL, and 24hrSHVL to organ dysfunction. We compared correspondence of SHVL to organ dysfunction with traditional indices of shock including the initial base deficit (BD) and the lowest pH measurement made in the first 24 hr after injury (minimum pH). RESULTS: SHVL at all three time intervals demonstrated higher correspondence to organ dysfunction (R2 = 0.48 to 0.52) compared to initial BD (R2 = 0.32) and minimum pH (R2 = 0.32). Additionally, we compared predictive capabilities of SHVL, initial BD and minimum pH to identify patients at risk of developing high-magnitude organ dysfunction by constructing receiver operator characteristic curves. SHVL at six hours and 24 hours had higher area under the curve compared to initial BD and minimum pH. CONCLUSION: SHVL is a non-invasive metric that can predict anticipated organ dysfunction and identify patients at risk for high-magnitude organ dysfunction after injury. LEVEL OF EVIDENCE: Prognostic study, level III.