Browsing by Author "Metzger, Cameron"

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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.