Study of Methemoglobin as a Biomarker of Tissue Hypoxia During Acute Hemodilution in Heart Surgery Patients
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|ClinicalTrials.gov Identifier: NCT01883713|
Recruitment Status : Completed
First Posted : June 21, 2013
Last Update Posted : April 17, 2018
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Acute and chronic anemia continue to be associated with increased mortality in a number of clinical settings, including cardiac and non-cardiac surgery. However, "We have no clinical measures that let us know of impending insufficient oxygenation as anemia progresses" (R.B. Weiskopf). The current proposal is based on experimental and clinical data which suggest that plasma methemoglobin (MetHb) may be a sensitive biomarker of tissue hypoxia and "anemic stress" in surgical patients.
Hypothesis: Increased methemoglobin is a biomarker of tissue hypoxia during acute anemia.
Primary Objective: To demonstrate a direct relationship between decreased Hb and increased MetHb in patients undergoing acute hemodilution on cardiopulmonary bypass (CPB).
|Condition or disease||Intervention/treatment|
|Other Functional Disturbances Following Cardiac Surgery||Device: Brain Oximetry|
|Study Type :||Observational|
|Actual Enrollment :||68 participants|
|Official Title:||A Prospective Analysis of Methemoglobin as a Biomarker of Tissue Hypoxia During Acute Hemodilutional Anemia in Patients Undergoing Heart Surgery|
|Study Start Date :||January 2013|
|Actual Primary Completion Date :||August 2016|
|Actual Study Completion Date :||August 2016|
Heart surgery during CPB
All patients undergoing heart surgery using cardiopulmonary bypass who have a pre-operative Hb value greater than 90 g/L, no evidence of hypoxemia (SaO2 > 90%) and no history of congenital methemoglobinemia. Exclusion criteria will include severe hypoxemia, acute or chronic renal failure requiring dialysis, emergency surgery or the lack of a PA catheter. Non invasive brain oximetry will be used to assess the brain oxygen tension during surgical procedure.
Device: Brain Oximetry
Non invasive brain oximeter will be applied on the patient's forehead to monitor the brain oxygen saturation throughout the surgery.
Other Name: Nonin equinox oximeter
- Arterial methemoglobin levels [ Time Frame: 18 months ]To determine if there is an association between increased methemoglobin and tissue hypoxia following heart surgery
- Cerebral tissue oxygen saturation [ Time Frame: 18 months ]
- Plasma erythropoietin levels [ Time Frame: 18 months ]
- Plasma nitrate/nitrite levels [ Time Frame: 18 months ]
- Plasma hepcidin levels [ Time Frame: 18 months ]Relationship between plasma hepcidin levels and hemoglobin levels
- Adverse outcomes including mortality, myocardial infarction, low output syndrome, stroke and renal dysfunction [ Time Frame: 18 months ]
Biospecimen Retention: Samples With DNA
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|Ages Eligible for Study:||18 Years to 65 Years (Adult, Older Adult)|
|Sexes Eligible for Study:||All|
|Accepts Healthy Volunteers:||No|
|Sampling Method:||Non-Probability Sample|
- patients undergoing heart surgery using cardiopulmonary bypass at St. Michael's Hospital who have a pre-operative Hb value greater than 90 g/L, no evidence of hypoxemia (SaO2 > 90%) and no history of congenital methemoglobinemia.
- severe hypoxemia, acute or chronic renal failure requiring dialysis, emergency surgery or the lack of a PA catheter (current standard of care at St. Michael's Hospital is to insert a PA catheter in > 90% of patients).
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01883713
|St. Michael's Hospital|
|Toronto, Ontario, Canada, M5B 1W8|
|Principal Investigator:||Gregory Hare, MD, PhD||Unity Health Toronto|
|Responsible Party:||Unity Health Toronto|
|Other Study ID Numbers:||
|First Posted:||June 21, 2013 Key Record Dates|
|Last Update Posted:||April 17, 2018|
|Last Verified:||April 2018|
Signs and Symptoms, Respiratory