Cardiac Surgery
Conditions
Brief summary
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.
Interventions
DEVICESpHb 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.
Sponsors
University of Minnesota
Study design
Observational model
CASE_CONTROL
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Agreement Between SpHb-Based and Pulmonary Artery Catheter Oxygen Delivery Index | Three intraoperative timepoints during cardiac surgery: baseline, post-heparin, and post-protamine | 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%. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Directional Agreement for Changes in Oxygen Delivery Index | Changes between consecutive intraoperative timepoints (baseline to post-heparin, post- heparin to post-protamine) during cardiac surgery | 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. |
| Correlation Between Oxygen Delivery Index and Arterial Lactate | Three intraoperative timepoints during cardiac surgery: baseline, post-heparin, and post- protamine | 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. |
| Agreement Between FloTrac and Swan-Ganz Cardiac Index | Three intraoperative timepoints during cardiac surgery: baseline, post-heparin, and post- protamine | 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%. |
| Impact of Baseline SpHb Calibration on Agreement | Three intraoperative timepoints during cardiac surgery: baseline, post-heparin, and post- protamine | 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. |
| SpHb Signal Usability Rate | Three intraoperative timepoints during cardiac surgery: baseline, post-heparin, and post- protamine | 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. |
| Perfusion Index Threshold for Acceptable SpHb Accuracy | Three intraoperative timepoints during cardiac surgery: baseline, post-heparin, and post- protamine | 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. |
Countries
United States
Contacts
CONTACTSherilyn Landree
PRINCIPAL_INVESTIGATORBenjamin Gorbaty, MD
University of Minnesota
Outcome results
None listed