Non-Invasive Hemoglobin Monitoring in Patients With Hemorrhage

Study Overview
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Brief Summary
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This study will evaluate the accuracy of two rapid methods of measuring hemoglobin in patients with suspected hemorrhage. These methods will be compared with standard laboratory measurements.

Detailed Description
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Anemia and bleeding are major causes of morbidity and mortality in both surgical and nonsurgical patients. The current standard of care for monitoring patients at risk for bleeding is serial measurement of hemoglobin levels. At present, the photometric cyanmethemoglobin method is the most widely used technique for monitoring hemoglobin in the lab, and is currently the gold standard. However, this method has potential for delay before final results are obtained. Immediate hemoglobin measurements are available with portable point-of-care devices such as the iSTAT, which can produce a measurement of hemoglobin concentration in less than 1 minute. Unfortunately, the accuracy of this device has been reported to vary with hemoglobin level, and as such may not be as accurate in detecting blood loss when compared with the gold standard of laboratory analysis. Recently, a noninvasive, spectrophotometry-based monitoring technology has been developed. This novel technology measures the differential optical density of wavelengths of light passed through the finger in a method similar to conventional pulse oximetry. While some studies have reported that this device appears to be accurate in patients undergoing elective surgical procedures, more recent work suggests that this accuracy degrades with increased blood loss, lower oximeter signal quality and lower absolute Hgb values. We will evaluate the accuracy of point-of-care and non-invasive SpHb measurements and utility of continuous hemoglobin monitoring in an intensive care unit setting. If these methods of rapid hemoglobin measurement can be validated in patients at risk for ongoing hemorrhage, use of this technology may result in earlier detection of ongoing hemorrhage, expedite appropriate treatment, and improve patient outcomes.

Official Title
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Non-Invasive Hemoglobin Monitoring in the Patient With Suspected Hemorrhage

Conditions
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Hemorrhage

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: admitted to surgical intensive care unit (SICU), and at risk of ongoing bleeding, and requires serial CBC measurements Exclusion Criteria: < 18 years of age, or a prisoner, or unable to have pulse oximetry readings (due to injuries, burns, amputations, or related problems)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 100 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Patients with Suspected Hemorrhage<br>There is a single group of patients in this study -- those with suspected hemorrhage who satisfy the inclusion and exclusion criteria. The same set of measurements will be take from each patients and those measurements will be compared with one another to determine accuracy. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| CBC Hemoglobin Measurement Compared to Non-invasive Radical-7 Measurement | Whenever blood was drawn for laboratory measurement of serum hemoglobin, we used one drop of blood to make point-of-care measurements using the CDC and Radical-7 methods. For purposes of reporting outcomes measures, we took an equally weighted average of measurements on each device (i.e., all measurement occasions on all patients). These are the means reported in the Outcome Measures Data Table. | n ≥ 1 measurements were taken each day. All measurements (n ≥ 7) from ICU Days 1-7 were used in Bland-Altman analysis, equally weighted. | 
| CBC Hemoglobin Measurement Compared to Non-invasive iSTAT Measurement | When blood was drawn for laboratory measurement of serum hemoglobin, one drop of blood was used to make point of care measurements using the CBC and iSTAT methods. For purposes of reporting outcomes measures, we took an equally weighted average of measurements on each device (i.e., all measurement occasions on all patients). These are the means reported in the Outcome Measures Data Table. | n ≥ 1 measurements were taken each day. All measurements (n ≥ 7) from ICU Days 1-7 were used in Bland-Altman analysis, equally weighted. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Hemorrhage, Hemoglobin, Non-invasive monitoring, Medical device accuracy