Study of Methemoglobin as a Biomarker of Tissue Hypoxia During Acute Hemodilution in Heart Surgery Patients

NCT01883713 | Completed DMC

• 1 other identifier: REB# 12-015
• Study Type: observational
• Target: 68
• Locations: 1 country
• Sites: 1

Brief Summary

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).

Conditions

Other Functional Disturbances Following Cardiac Surgery

Keywords

anemia; CPB; methemoglobin; hypoxia

Outcome Measures

Primary Outcomes (1)

• Arterial methemoglobin levels

  To determine if there is an association between increased methemoglobin and tissue hypoxia following heart surgery

  18 months

Secondary Outcomes (4)

• Cerebral tissue oxygen saturation

  18 months

• Plasma erythropoietin levels

  18 months

• Plasma nitrate/nitrite levels

  18 months

• Plasma hepcidin levels

  18 months

Other Outcomes (1)

• Adverse outcomes including mortality, myocardial infarction, low output syndrome, stroke and renal dysfunction

  18 months

Study Arms (1)

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

Interventions

Brain Oximetry DEVICE

Non invasive brain oximeter will be applied on the patient's forehead to monitor the brain oxygen saturation throughout the surgery.

Also known as: Nonin equinox oximeter

Heart surgery during CPB

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

heart surgery with cardiopulmonary bypass

You may qualify if:

• 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.

You may not qualify if:

• 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).

Sponsors & Collaborators

• Unity Health Toronto: lead

Study Sites (1)

St. Michael's Hospital

Toronto, Ontario, M5B 1W8, Canada

Location

Related Publications (1)

• Hare GMT, Han K, Leshchyshyn Y, Mistry N, Kei T, Dai SY, Tsui AKY, Pirani RA, Honavar J, Patel RP, Yagnik S, Welker SL, Tam T, Romaschin A, Connelly PW, Beattie WS, Mazer CD. Potential biomarkers of tissue hypoxia during acute hemodilutional anemia in cardiac surgery: A prospective study to assess tissue hypoxia as a mechanism of organ injury. Can J Anaesth. 2018 Aug;65(8):901-913. doi: 10.1007/s12630-018-1140-0. Epub 2018 Apr 25.

  PMID: 29696581 DERIVED

Biospecimen

Retention: SAMPLES WITH DNA

Plasma will be retained for analysis of plasma erythropietin, hepcidin and and nitrate/nitrite levels

MeSH Terms

Conditions

Anemia; Hypoxia

Condition Hierarchy (Ancestors)

Hematologic Diseases; Hemic and Lymphatic Diseases; Signs and Symptoms, Respiratory; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Officials

• Gregory Hare, MD, PhD

  Unity Health Toronto

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: March 11, 2013
• First Posted: June 21, 2013
• Study Start: January 1, 2013
• Primary Completion: August 1, 2016
• Study Completion: August 1, 2016
• Last Updated: April 17, 2018

Record last verified: 2018-04

Locations

CA (1)