New Study in Anesthesia & Analgesia Demonstrates Frequent Occurrence of Low Cardiac Index Despite Normotension, Using Argos® Monitor

We are proud to share that a new study published in Anesthesia & Analgesia (January 2025) highlights the power of the Argos® Cardiac Output Monitor in revealing critical hemodynamic insights during cardiac surgery.
Key Findings
  • In a prospective cohort of 101 patients undergoing coronary artery bypass (CAB) surgery (July 2021–November 2023), the Argos monitor continuously recorded cardiac index (CI) every 5 seconds. Remarkably, patients experienced a mean of 86.4 minutes of low CI (<2 L/min/m²) during surgery—even when mean arterial pressure (MAP) was within normal levels. PubMed
  • Notably, 69% of low CI episodes occurred while blood pressure was normal, underscoring that normotension may not guarantee adequate perfusion. PubMed
  • The correlation between CI and MAP was modest overall (mean r ≈ 0.33), though stronger pre-cardiopulmonary bypass (CPB) (r ≈ 0.53) than post-CPB (r ≈ 0.29), indicating that blood pressure alone is an unreliable proxy for cardiac output during surgery. PubMed
  • An exploratory link emerged between longer duration of low CI and increased odds of postoperative acute kidney injury (AKI)—with each additional minute of low CI associated with higher AKI risk (OR = 1.09; 95% CI 1.01–1.13; P = .018). PubMed
Why This Matters
This study highlights the unique value of continuous, noninvasive cardiac output monitoring with Argos—capabilities that uncover potentially harmful low-flow periods that would otherwise go unnoticed with standard blood pressure monitoring. Detecting these episodes may offer a pathway to improved outcomes, including reducing the risk of AKI.
Read the full study for more details:
“Occurrence of Low Cardiac Index During Normotensive Periods in Cardiac Surgery: A Prospective Cohort Study Using Continuous Noninvasive Cardiac Output Monitoring” in Anesthesia & Analgesia, January 2025.