Hemodynamic Monitor

Hemodynamic Monitor

Retia has created a new, less-invasive system to monitor cardiac outpt (CO) and other key hemodynamic parameters accurately when patients go unstable. By monitoring changes in CO, clinicians can detect, diagnose and treat life-threatening conditions better, leading to improved outcomes and lower costs. The patented platform technology behind Retia's monitor was licensed exclusively from Michigan State and MIT.

The Retia Monitor connects to existing radial arterial catheters, which are routinely placed in high-risk patients in the OR and ICU (95% of the time in the US). 

The Retia Monitor offers early detection of changes in CO by processing existing peripheral blood pressure signals using a proprietary algorithm. This approach is called "pulse contour analysis." Retia's algorithm models blood circulation and accounts for beat-to-beat variations in the blood pressure signal. These variations, ignored in other pulse contour algorithms, turn out to be critical to the calculation of CO. Retia also uses additional non-invasive sensors to help the monitor to maintain its accuracy during severe vasodilation or vasoconstriction. Other competing system are actually contraindicated during these situations and have been shown to fail dramatically in numerous, clinically-relevant situations. The Retia algorithm has been validated in animals across a wide range of hemodynamic conditions and in over 300 human subjects, including the critically ill.


Selected results:

12.9% calibrated CO error compared to aortic flow probe in 6 animals during drug and volume interventions

     [IEEE Trans Biomed Eng, 53(3):459, 2006]    

15.1% calibrated CO error compared to Doppler ultrasound in 10 healthy humans during drug and postural interventions

     [J Appl Physiol, 101:598, 2006]

Reliable tracking of CO reductions in 129 healthy humans during central hypovolemia

     [Br J Anaesth, 106(1):23, 2011]

18.5% calibrated CO error compared to pulmonary artery catheter (single bolus thermodilution) in 184 critically ill patients

     [Br J Anaesth, doi: 10.1093/bja/aes099, 2012]


By comparison current products have large failures in key clinical situations including:

1. Hemorrhage

2. Sepsis

3. End stage liver failure and liver transplants - these have large fluid shifts and other hemodynamic changes

4. Hypothermia

5. Post-op high-risk surgery




Mukkamala R, Reisner AT, Hojman HM, Mark RG, Cohen RJ. Continuous cardiac output monitoring by peripheral blood pressure waveform analysis. IEEE Trans Biomed Eng, 53:459-467, 2006.

Reisner AT, Xu D, Ryan KL, Convertino VA, Rickards CA, Mukkamala R. Comparison of cardiac output by blood pressure waveform analysis methods during experimental human hypovolemia and resuscitation. Br J Anaesth, 106:23-30, 2011.

Lu Z, Mukkamala R. Continuous cardiac output monitoring in humans by invasive and non-invasive peripheral blood pressure waveform analysis. J Appl Physiol, 101:598-608, 2006.

Zhang G, Mukkamala R. Continuous and minimally invasive cardiac output monitoring by long time interval analysis of a radial arterial blood pressure waveform: assessment using a large, public intensive care unit patient database. Submitted.

Swamy G, Xu D, Olivier NB, Mukkamala R. An adaptive transfer function for deriving the aortic pressure waveform from a peripheral artery pressure waveform. Am J Physiol, 297:H1956-H1963, 2009.

Swamy G, Kuiper J, Gudur MSR, Olivier NB, Mukkamala R. Continuous left ventricular ejection fraction monitoring by aortic pressure waveform analysis. Ann Biomed Eng, 37:1055-1068, 2009.

Mukkamala R, Xu D. Continuous and less invasive central hemodynamic monitoring by blood pressure waveform analysis. Am J Physiol, 299:H584-H599, 2010.

Bein B, Meybohm P, Cavus E, Renner J, Tonner PH, Steinfath M, Scholz J, Doerges V. The reliability of pulse contour-derived cardiac output during hemorrhage and after vasopressor administration. Anesth Analg, 105:107-113, 2007.

Camporota L, Beale R. Pitfalls in haemodynamic monitoring based on the arterial pressure waveform. Crit Care, 14:124, 2010.

Chan JS, Segara D, Nair P. Measurement of cardiac output with a non-invasive continuous wave Doppler device versus the pulmonary artery catheter: a comparative study. Crit Care Resusc, 8:309-314, 2006.

Compton FD, Zukunft B, Hoffmann C, Zidek W, Schaefer JH. Performance of a minimally invasive uncalibrated cardiac output monitoring system (FlotracTM/VigileoTM) in haemodynamically unstable patients. Br J Anaesth, 100:451-456, 2008.

Cooper ES, Muir WW. Continuous cardiac output monitoring via arterial pressure waveform analysis following severe hemorrhagic shock in dogs. Crit Care Med, 35:1724-1729, 2007.

Duffy AL, Butler AL, Radecki SV, Campbell VL. Comparison of continuous arterial pressure waveform analysis with the lithium dilution technique to monitor cardiac output in conscious dogs with systemic inflammatory response syndrome. Am J Vet Res, 70:1365-1373, 2009.

Eleftheriadis S, Galatoudis Z, Didilis V, Bougioukas I, Schon J, Heinze H, Berger K-U, Heringlake M. Variations in arterial blood pressure are associated with parallel changes in FlowTrac/Vigioleo®-derived cardiac output measurements: a prospective comparison study. Crit Care, 13:R179, 2009.

Gruenewald M, Renner J, Meybohm P, Hocker J, Scholz J, Bein B. Reliability of continuous cardiac output measurement during intra-abdominal hypertension relies on repeated calibrations: an experimental animal study. Crit Care, 12:R132, 2008.

Johansson A, Chew M. Reliability of continuous pulse contour cardiac output measurement during hemodynamic instability. J Clin Monit Comput, 21:237-242, 2007.

Kuper M. Continuous cardiac output monitoring. Current Anaesth Crit Care, 15:367-377, 2004.

Piehl MD, Manning JE, McCurdy SL, Rhue TS, Kocis KC, Cairns CB, Cairns BA. Pulse contour cardiac output analysis in a piglet model of severe hemorrhagic shock. Crit Care Med, 36:1189-1195, 2008.

Romagnoli S, Romano SM, Bevilacqua S, Ciappi F, Lazzeri C, Peris A, Dini D, Gelsomino S. Cardiac output by arterial pulse contour: reliability under hemodynamic derangements. Interact CardioVasc Thorac Surg, 8:642-646, 2009.

Schuerholz T, Cobas Meyer M, Friedrich L, Przemeck M, Sumpelmann R, Marx G. Reliability of continuous cardiac output determination by pulse-contour analysis in porcine septic shock. Acta Anaesthesiol Scand, 50:407-413, 2006.