A Study of Tris-Hydroxymethyl Aminomethane (THAM) Versus Sodium Bicarbonate in Cardiac Surgical Patients

THAM VErsus Sodium BiCarbOnate In CaRdiac SuRgical PatiEnts, A PragmatiC, Comparative-effectiveness Prospective Trial

The purpose of this research is to determine if two commonly used medications to treat metabolic acidosis in the setting of cardiac surgery, sodium bicarbonate and THAM, are equivalent.

Study Overview

• Status: Not yet recruiting
• Conditions: Metabolic Acidosis
• Intervention / Treatment: Drug: Tris-hydroxymethyl Aminomethane; Drug: Sodium bicarbonate

• Study Type: Interventional
• Enrollment (Estimated): 250
• Phase: Phase 4

Contacts and Locations

• Study Contact: Name: Nicole M. Lenort, RRT, LRT; Phone Number: 866-265-9263; Email: Lenort.Nicole@mayo.edu

Study Locations

• United States
  • Minnesota
    • Rochester, Minnesota, United States, 55901
      • Mayo Clinic
      • Contact: Nicole M. Lenort, RRT, LRT; Phone Number: 866-265-9263
      • Principal Investigator: Misty A. Radosevich, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

• Inclusion criteria

  • Cardiothoracic surgery with use of cardiopulmonary bypass
  • Presence of metabolic acidosis (defined as a base excess of <-5)
  • Minnesota Research Authorization

• Exclusion criteria

  • Non-cardiac surgery patients or cardiac surgery without cardiopulmonary bypass
  • Absence of metabolic acidosis (metabolic acidosis being defined as a base excess of <-5)
  • Pregnant patients
  • Prisoners
  • Opt out of Minnesota Research Authorization

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Tris-hydroxymethyl aminomethane (THAM); Patients randomized to the THAM arm will be treated with tris-hydroxymethyl aminomethane. Dosage: Base excess less than -5, administer 500 mL of THAM	Drug: Tris-hydroxymethyl Aminomethane; Patients in the ICU following cardiothoracic surgery with use of cardiopulmonary bypass, requiring treatment for metabolic acidosis (base excess less than -5), will receive tris-hydroxymethyl aminomethane (THAM) if randomized to the THAM arm.; Other Names: THAM
Active Comparator: Sodium bicarbonate (Bicarb); Patients randomized to the Bicarb arm will be treated with sodium bicarbonate (Bicarb). Dosage: Base excess less than -5, administer 100 mEq of sodium bicarbonate	Drug: Sodium bicarbonate; Patients in the ICU following cardiothoracic surgery with use of cardiopulmonary bypass and requiring treatment for metabolic acidosis (base excess less than -5), will receive sodium bicarbonate (Bicarb) if randomized to the Bicarb arm.; Other Names: Bicarb

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in pH following buffer administration	pH will be measured via arterial blood gas test	Baseline, 2 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in sodium	Sodium will be measured via blood test and reported in reported in mEq/L (milliequivalents per liter)	Baseline, 2 hours
Change in potassium	Potassium will be measured via blood test and reported in reported in mEq/L (milliequivalents per liter)	Baseline, 2 hours
Change in lactate	Lactate will be measured via blood test and reported in mmol/L (millimoles per liter)	Baseline, 2 hours
Change in (arterial partial pressure of carbon dioxide) PaCO2	PaCO2 will be measured via arterial blood gas test, reported as mmHg (millimeters of mercury)	Baseline, 2 hours
Change in cardiac index	Cardiac index is determined by dividing cardiac output by body surface area, with a normal range of 2.5-4.0 L/min/m²	Baseline, 2 hours
Change in Mean arterial pressure (MAP)	Mean arterial pressure (MAP) is the average pressure in the arteries throughout one cardiac cycle. Normal MAP is between 70 and 100, reported as mmHg (millimeters of mercury)	Baseline, 2 hours
Change in vasopressor dosing		Baseline, 2 hours
Change in inotrope dose		Baseline, 2 hours
Duration of mechanical ventilation	Duration of mechanical ventilation will be reported in hours	7 days
Incidence of acute kidney injury	Number of patients who develop acute kidney injury	7 days
Incidence of renal replacement therapy	Number of patients who newly require renal replacement therapy	7 days
ICU length of stay	Number of days patient stays in ICU	7 days
Hospital length of stay	Number of days patient is hospitalized	7 days

Collaborators and Investigators

• Sponsor: Mayo Clinic
• Investigators: Principal Investigator: Misty A. Radosevich, MD, Mayo Clinic

Publications and helpful links

General Publications

• Radosevich MA, Wieruszewski PM, Wittwer ED. Tris-Hydroxymethyl Aminomethane in Critically Ill Adults: A Systematic Review. Anesth Analg. 2023 Nov 1;137(5):1007-1018. doi: 10.1213/ANE.0000000000006485. Epub 2023 Apr 19.

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): February 1, 2027
• Study Completion (Estimated): August 1, 2027

Study Registration Dates

• First Submitted: February 14, 2026
• First Submitted That Met QC Criteria: February 14, 2026
• First Posted (Actual): February 20, 2026

Study Record Updates

• Last Update Posted (Actual): June 15, 2026
• Last Update Submitted That Met QC Criteria: June 11, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: cardiac surgery; Sodium bicarbonate; metabolic acidosis; THAM
• Additional Relevant MeSH Terms: Metabolic Diseases; Acid-Base Imbalance; Nutritional and Metabolic Diseases; Acidosis; Organic Chemicals; Inorganic Chemicals; Alcohols; Glycols; Anions; Ions; Electrolytes; Propylene Glycols; Sodium Compounds; Carbon Compounds, Inorganic; Carbonates; Carbonic Acid; Sodium Bicarbonate; Bicarbonates; Tromethamine
• Other Study ID Numbers: 25-002104

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No