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San Francisco Injury Center (SFIC) »  Continuous Hemoglobin Monitoring

Continuous Hemoglobin Monitoring in Acute Care

Project Director/Lead Investigator: Mitchell Cohen, MD

Brief Summary of Project: In trauma, efforts to diagnose and track bleeding are paramount to the restoration of circulatory homeostasis. Unfortunately, the best current measure of hemoglobin (the complete blood count CBC) is obtained by an invasive blood draw. This test suffers from being intermittent, expensive, and slow. We are testing the hypothesis that the use of continuous hemoglobin (SpHb) monitoring to measure hemoglobin (Hb) concentration will provide a clinically useful measure of bleeding and anemia that is superior to current techniques. We will further test the hypothesis that continuous monitoring of hemoglobin in conjunction with our multivariate bioinformatics ICU data collection and analysis will provide superior information about a patient's perfusion status and predictive information about a patient's physiologic state and clinical trajectory. Ultimately, we hypothesize that we can create a predictive model of clinical outcomes related to traumatic injury and acute anemia to design interventions to improve tissue hypoxia.

Specific Aims:
1. To determine the ability of continuous, noninvasive Pulse-CO Oximetry to accurately provide Hb measurement and provide superior tracking of physiologic trajectory in severely injured trauma patients.
1a: To determine if continuous Hb measurements directly correlate with standard intermittent laboratory Hb measurements in severely injured patients beginning immediately after trauma.
1b: To determine if continuous Hb measurements will provide superior tracking of bleeding and hemostasis in post trauma patients who are being monitored for potential ongoing bleeding.
1c: To determine if continuous Hb measurements will provide superior information to guide transfusions in trauma patients.
1d: To determine if continuous Hb measurements will provide superior prognostic information about morbidity (infection, lung injury, multiple organ failure, increased length of ICU/Hospital stay) and mortality after injury.
2. To determine if continuous Hb measurement can be combined with our already monitored measures of tissue oxygen and tissue blood flow to provide superior measurement of perfusion and patient physiology.
3. To determine if continuous Hb measurement will integrate with other continuous ICU data to provide superior characterization of physiologic state and state trajectory in a multivariate informatic model.

Studies and Results: This prospective cohort study will follow the clinical course of 200 trauma patients on admission to the emergency department (who require ICU admission) and for the subsequent 28 days. The Masimo Radical-7 Pulse CO-Oximeters will be placed upon ICU arrival and will remain for 96 hours or until ICU discharge (whichever is first). We have created an extensive web-based relational database (Quesgen Systems Inc. Burlingame, CA) for the direct entry and management of relevant patients. The study coordinators will record clinical data including inclusion and exclusion criteria, daily clinical and physiologic data, relevant laboratory data, and the endpoints of this study. Primary outcome measures include incidence of bleeding, accuracy of hemoglobin measures, coagulation abnormalities, and total blood product transfusions. Secondary endpoints include incidence of organ injury, ventilator associated pneumonia, 28-day mortality, ventilator-free days, ICU stay, hospital stay, and incidence of nosocomial infections.

Future: Due to a change in leadership at the company that manufactures the monitors there was a delay in beginning this project. It is now on track and we expect to begin enrollment in Summer 2011 upon receipt of funding from the Masimo Corporation. We plan to complete the study in 18 months, representing approximately 12 months for enrollment and 6 months for analysis. We expect interim data analysis prior to completion.


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