Support and FAQs

Frequently Asked Questions:

  • What are the indications for the Argos Cardiac Output monitor?

    The Argos Cardiac Output monitoring device is intended for use on patients above the age of 18. It is intended to be used as a hemodynamic monitor for monitoring cardiac output and its derived parameters on patients in the intensive care unit (ICU) or in the operating room (OR).

  • Are there any contraindications for use of the Argos monitor?

    The Argos monitor is contraindicated in the following patients:

    • Patients on any type of mechanical cardiac support (e.g., intra-aortic balloon pumps, LVADs)
    • Patients with moderate-to-severe aortic valve regurgitation.


    ⚠ WARNING The Argos monitor is not indicated for use with pediatric patients.

  • In which patients is use of the Argos monitor appropriate?

    The Argos monitor is appropriate for use in any patient who receives a radial arterial catheter for blood pressure monitoring. Typical patient types or clinical situations include:

    • Shock States/Low Blood Pressure
      • Hypovolemia
      • Cardiogenic Shock
      • Distributive Shock (Sepsis)
    • Patients treated with fluids, inotropes, vasopressors or vasodilators
      • Medium and High-risk Surgical Patients
      • Perioperative fluid management,
      • Enhanced Recovery After Surgery (ERAS)
    • OR recovery
    • Critically ill patients in the intensive care unit
      • Post-surgical patients
      • Sepsis
      • Congestive Heart Failure (CHF)
      • Anyone at-risk of going into circulatory shock
  • Can the Retia Argos Monitor be used during surgical procedures?

    Yes, in fact, Retia Argos monitors are routinely used for perioperative hemodynamic management programs in numerous hospitals.

  • Does the Argos monitor work well in very thin or in obese patients?

    Yes.  The Argos monitor is not impacted by body mass and will provide accurate results for all types of patients.

  • How is the Argos monitor different than the other hemodynamic monitors I’ve tried?

    The three main benefits of the Argos Monitor are:

    • A novel, proprietary algorithm that is designed to provide superior accuracy by accounting for wave reflection and using a more precise model of the circulation.
    • An intuitive user interface and easy to read display enables quick interpretation of hemodynamic data.
    • Total cost of ownership is approximately 75% to 80% less costly than other hemodynamic monitors.  This is primarily due to the fact that proprietary disposables are not required, unlike most other CO monitors. This lower operating cost allows each ICU and OR patient to be placed on and monitored with the Argos CO Monitor early so that a baseline cardiac output is captured prior to a patient’s condition deteriorating.  Having the baseline cardiac output when a patient deteriorates will facilitate rapid assessment of their critical needs for stabilization.
  • What is the cost of the Argos monitor and how does this cost compare with other hemodynamic monitors?

    Cost information is available here

    Please speak to your Retia Sales Representative or contact us for more information.

  • How does the Argos monitor determine cardiac output?

    The Argos monitor is based on Multi-Beat Analysis (MBATM), a proprietary technology that Retia developed over the past 15 years in collaboration with researchers at Michigan State University and the Massachusetts Institute of Technology. The algorithm has been rigorously tested and validated in the most challenging patient populations (including critically ill patients with sepsis, heart failure, and undergoing major cardiac surgery, neurosurgery, major abdominal surgery, liver transplants and others).

    The MBA algorithm uses two stages to model the true ABP pulse:

    1. Construction of the blood pressure response to a single contraction by modeling the immediate history of previous beats, and
    2. Estimation of the circulatory system parameters beat by beat which is then fitted to the measured ABP using a three parameter model of the circulation.  This avoids the confounding effects of wave reflection which amplify and distort the peripheral blood pressure waveform.

    The additional information derived from using multiple beats in the analysis of the circulation can yield greater accuracy than a corresponding single-beat approach.

    For additional information about how the Argos monitor determines cardiac output, please visit the “How it Works” section of this website.

  • Does the Argos monitor measure CVP, PA Pressure and Sv02?

    No. Consistent with other A-line hemodynamic monitors, the Argos Monitor measures CO (Cardiac Output), CI (Cardiac Index), MAP (Mean Arterial Pressure), HR (Heart Rate), BP (Blood Pressure), SV (Stroke Volume), SVI (Stroke Volume Index), SVR (Systemic Vascular Resistance), SVRI (Systemic Vascular Resistance Index), PPV (Pulse Pressure Variation). 

  • What published clinical data support the use of the Argos monitor?

    The Argos monitor has been tested in multiple clinical centers on the most challenging patient populations, including cardiac surgeries, liver transplants, major neurosurgeries, major abdominal surgery, and major hepatobiliary surgeries. The clinical centers include Columbia University Medical Center, Duke University, Jefferson Hospital, University of Michigan, University of Virginia, University of Hamburg-Eppendorf (Germany), Hopital Lariboisiere, Paris, and several others. Additional studies are on-going, including an upcoming multi-center study led by Mt. Sinai and Scripps. A complete list of publications can be found here.

  • What is the importance of hemodynamic monitoring?

    Hemodynamic monitors are useful in aiding the detection, diagnosis and titration of therapy in response to circulatory shock.  An emerging application is the use of hemodynamic monitoring as the input for sophisticated predictive analytic algorithms to help anticipate and prevent the transition of patients into shock.  According to  the MIMIC data base of 5,347 U.S. patients, 93.4% of ICU patients will develop shock, defined as a failure to respond sufficiently to high dose of vasopressors, which has a short-term mortality greater than 50%. It is clear that early detection and optimized resuscitation is important in the management of any patient who is at-risk for shock. Additional information about the importance of hemodynamic monitoring is available here.

  • Why should I use the Argos monitor over other cardiac output monitors?

    Some may argue that the choice of hemodynamic monitor used is unimportant, and that following a fluid optimization protocol is what matters. For low-risk and some medium-risk surgical patients who do not have co-morbidities, this approach will likely yield acceptable results so long as the clinician errs on the side of over-resuscitation. Typically, the risks of under-resuscitation are lack of sufficient oxygen delivery, rapidly leading to organ failure, whereas the risk of over-resuscitation is edema, generally leading to impeded bowel function and excess length of stay.1

    For high-risk patients in the ICU and in high-risk surgeries, however, the situation is much different. These patients have fewer physiologic reserves with which to tolerate pronounced variations in therapy and/or physiologic stressors. The risk of under-resuscitation in these patients is organ failure due to lack of sufficient oxygen delivery. For example, under-resuscitation can lead to acute kidney injury and nonocclusive mesenteric ischemia.2,3 However, over-resuscitation can increase the risk of abdominal compartmental syndrome, acute kidney injury, and acute respiratory distress syndrome (ARDS), especially in burn patients.4-6 In patients with elevated cardiovascular risk (such as hypertension or heart failure), fluid overload may trigger heart failure, potentially causing cardiac depression, especially in patients with septic cardiomyopathy.7

    These findings underscore the importance of implementing resuscitation protocols that are based on patients’ actual hemodynamic status rather than using iterative approaches (fluid or drug challenges) or patient weight-based protocols.  Retia’s Argos Hemodynamic Monitor provides superior accuracy via the Multi-Beat Algorithm (MBAtm) to assess the patient’s actual hemodynamic status.  In addition, because proprietary disposables are not necessary, there is no additional cost to monitor each patient.  This enables clinicians to ensure that each ICU or OR patient is provided a CO monitor that will capture their baseline should they develop shock.  Rapid, stabilizing action can then be taken by the critical care practitioner.

  • How do I connect the Argos monitor to a patient’s vital signs monitor?

    Please see Installation and Use.

  • In the unlikely event that my vital signs monitor is not compatible with the Argos monitor, is there an alternative method to send the blood pressure wave form to The Argos?

    Yes. Please contact your Retia representative.

  • Does acquiring the blood pressure signal directly from the vital signs monitor instead of using a separate pressure transducer impact the accuracy of the Argos monitor?

    No. All the validation studies and numerous independent studies were conducted using this method and proved superior accuracy.

  • Do I have to use a specialized Retia Medical disposable pressure transducer for functionality?

    No.  You can connect the Argos monitor directly to your vital signs monitor. This eliminates the need for disposables, providing your hospital with significant cost savings over time.

  • Will the Argos monitor be accurate if arterial line damping occurs?

    Arterial line damping will result in inaccurate blood pressure waveforms, and will thus cause all pulse-contour based CO monitors to be inaccurate.  The arterial line should be flushed to resolve this problem.

  • Does the Argos monitor contain a battery?

    Yes. The Argos monitor contains a battery that can provide approximately 30 minutes of functionality, which is typically sufficient for transferring a patient between the OR and the ICU.

  • Does the Argos Cardiac Output Monitor require calibration?

    No.  The Argos Cardiac Output Monitor is uncalibrated.  The user simply inputs the patient age, height, weight and gender into the monitor and it calculates the cardiac output based on this information and analysis of the blood pressure waveform.

  • Has the Argos monitor been cleared by the FDA?

    Yes.  In December 2018, Retia Medical LLC received FDA 510k Clearance to market the Argos Hemodynamic Monitor in the U.S.A. (K181372)

  1. Navarro et al, Perioperative Medicine, 2015; 4:3.
  2. Maron, SA, et al, “Inflammation and the Host Response to Injury Collaborative Research Program: Hold the pendulum: Rates of acute kidney injury are increased in patients who receive resuscitation volumes less than predicted by the Parkland equation,” Ann Surg, 2016; 264:1142-7.
  3. Soussi S, et al, “Risk factors for acute mesenteric ischemia in critically ill burn patients – a matched case-conrol study,” Shock 2018 Mar 20 [Epub ahead of print].
  4. Klein, MB et al, “The association between fluid administration and outcome following major burn: A multicenter study,” Ann Surg, 2007, 264:622-8.
  5. Markell KW, et al, “Abdominal complications after severe burns,” J Am Coll Surg, 2009; 208:940-7; discussion 947-9.
  6. Soussi S, et al, “Early Hemodynamic Management of Critically Ill Burn Patients,” Anesthesiology 2018; 129:583-9.
  7. Sasai et al., “Reliability of central venous pressure to assess left ventricular preload for fluid resuscitation in patients with septic shock,” J. Intensive Care, vol. 2, no. 1, pp. 1–7, 2014.