Validation and Feasibility of Noninvasive Oxygen Delivery Index Monitoring in Cardiac Surgery Patients

This study will establish the feasibility and preliminary validity of real-time oxygen delivery index (DO₂i) monitoring using noninvasive hemoglobin (SpHb, Masimo) and minimally invasive cardiac output (FloTrac, Edwards) in cardiac surgery patients.

Study Overview

• Status: Not yet recruiting
• Conditions: Cardiac Surgery
• Intervention / Treatment: Device: SpHb monitor

• Study Type: Observational
• Enrollment (Estimated): 150

Contacts and Locations

• Study Contact: Name: Sherilyn Landree; Phone Number: (612) 282-3705; Email: landr184@umn.edu

Study Locations

• United States
  • Minnesota
    • Minneapolis, Minnesota, United States, 55455
      • University of Minnesota
      • Contact: Sherilyn Landree; Phone Number: 612-282-3705; Email: landr184@umn.edu

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

Adults undergoing cardiac surgery

Description

Inclusion Criteria:

• Adults ≥ 18 years undergoing cardiac surgery
• Placement of pulmonary artery catheter with continuous cardiac output (CCO) as part of routine clinical care
• Placement of arterial line with FloTrac as part of routine clinical care
• Availability of ≥ 3 arterial blood gas samples at specified timepoints

Exclusion Criteria:

• Mechanical circulatory support planned or in use (IABP, Impella, ECMO)
• Patients without BOTH pulmonary artery catheter with CCO and arterial line with FloTrac
• Patients who are Research Opt-Out

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Cardiac surgery patients; The study uses a within-patient repeated-measures design, where each patient serves as their own control across the three timepoints. The following measures will be recorded: SpHb, Perfusion Index, SpO₂ from Masimo Radical-7 (timestamp to HH:MM:SS); FloTrac cardiac index from Edwards HemoSphere; ABG hemoglobin, SaO₂, PaO₂, and lactate from ABL analyzer; Continuous cardiac index from Swan-Ganz catheter; Mean arterial pressure, heart rate and rhythm; Patient temperature from the bladder; Pressor requirements

Device: SpHb monitor; The SpHb monitor is an FDA approved device being used according to its approved indications. No additional invasive procedures, blood draws, or interventions are performed for research purposes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Agreement Between SpHb-Based and Pulmonary Artery Catheter Oxygen Delivery Index	Bias and 95% limits of agreement between monitor-derived DO₂i (calculated from continuous SpHb and FloTrac cardiac index) and pulmonary artery catheter DO₂i (calculated from arterial blood gas hemoglobin and Swan-Ganz cardiac index), analyzed using Bland-Altman method with mixed-effects modeling to account for repeated measures. Agreement is considered acceptable if percentage error is <30%.	Three intraoperative timepoints during cardiac surgery: baseline, post-heparin, and post-protamine

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Directional Agreement for Changes in Oxygen Delivery Index	Four-quadrant concordance rate (with 15% exclusion zone) for directional changes in DO₂i between consecutive timepoints. Concordance is defined as agreement in direction of change (increase vs decrease) between monitor-derived and gold-standard DO₂i measurements. Scores range from 0- 100%, with higher percentages indicating better directional agreement.	Changes between consecutive intraoperative timepoints (baseline to post-heparin, post- heparin to post-protamine) during cardiac surgery
Correlation Between Oxygen Delivery Index and Arterial Lactate	Pearson or Spearman correlation coefficient between DO₂i (both monitor-derived and gold- standard) and simultaneously measured arterial lactate concentration. Correlation coefficients range from -1 to +1, with negative values indicating inverse relationship between DO₂i and lactate.	Three intraoperative timepoints during cardiac surgery: baseline, post-heparin, and post- protamine
Agreement Between FloTrac and Swan-Ganz Cardiac Index	Percentage error between FloTrac arterial pressure-based cardiac index and Swan-Ganz thermodilution continuous cardiac index. Percentage error is calculated as (1.96 × SD of differences) / mean cardiac index × 100%. Agreement is considered acceptable if percentage error is <30%.	Three intraoperative timepoints during cardiac surgery: baseline, post-heparin, and post- protamine
Impact of Baseline SpHb Calibration on Agreement	Comparison of limits of agreement before and after in vivo SpHb calibration (baseline- adjusted SpHb using first arterial blood gas hemoglobin value as reference). Measured as change in bias and 95% limits of agreement between uncalibrated and baseline-calibrated SpHb-based DO₂i compared to gold standard.	Three intraoperative timepoints during cardiac surgery: baseline, post-heparin, and post- protamine
SpHb Signal Usability Rate	Percentage of planned timepoints with valid SpHb signal defined by perfusion index (PI) ≥ 0.5. Scores range from 0-100%, with 100% indicating valid signal at all timepoints.	Three intraoperative timepoints during cardiac surgery: baseline, post-heparin, and post- protamine
Perfusion Index Threshold for Acceptable SpHb Accuracy	Minimum perfusion index value associated with acceptable SpHb accuracy, defined as SpHb bias within ±1 g/dL of arterial blood gas hemoglobin. Perfusion index values range from 0-20%, with higher values indicating better peripheral perfusion.	Three intraoperative timepoints during cardiac surgery: baseline, post-heparin, and post- protamine

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Major Adverse Cardiac Events (Exploratory)	Composite endpoint including all-cause mortality, myocardial infarction (elevated troponin with ECG changes or clinical symptoms), stroke (new neurologic deficit with imaging confirmation), or urgent revascularization.	Within 30 days of surgery
Acute Kidney Injury (Exploratory)	AKI defined and staged using KDIGO criteria based on postoperative serum creatinine changes: Stage 1 (1.5-1.9× baseline or ≥0.3 mg/dL increase), Stage 2 (2.0-2.9× baseline), Stage 3 (≥3× baseline or ≥4.0 mg/dL or initiation of renal replacement therapy).	Within 30 days of surgery

Collaborators and Investigators

• Sponsor: University of Minnesota
• Investigators: Principal Investigator: Benjamin Gorbaty, MD, University of Minnesota

Study record dates

Study Major Dates

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

Study Registration Dates

• First Submitted: April 30, 2026
• First Submitted That Met QC Criteria: April 30, 2026
• First Posted (Actual): May 7, 2026

Study Record Updates

• Last Update Posted (Actual): May 7, 2026
• Last Update Submitted That Met QC Criteria: April 30, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: ANES-2026-34768

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes