The Nexfin HD - The Nexfin HD -

Potential ApplicationsPotential Applications

Azriel Perel

Professor and ChairmanDepartment of Anesthesiology and Intensive CareSheba Medical Center, Tel Aviv University, Israel

ESCTAIC Amsterdam 2010

DisclosureDisclosure

The speaker cooperates with the following companies The speaker cooperates with the following companies

BMEYEBMEYE

PULSION PULSION

What Is the Best Way To Measure Cardiac OutputWhat Is the Best Way To Measure Cardiac Output? ? Who Cares, AnywayWho Cares, Anyway? ?

Caruso LJ et al. Caruso LJ et al. Chest.Chest. 2002;122:771-774 2002;122:771-774

Monitor wizards can be dangerousMonitor wizards can be dangerous

Robin ED, McCauley RF. Chest 1998; 114: 1511

I have a suspicion that even the medical device manufacturers realize that CO is not an important

variable in the critical care arena .

…PPV alone is the best way to predict volume responsiveness. Therefore, it is less clear why we want

to know the CO in the first place .

This explains why all of the recently marketed devices purport a slew of other data (e.g., stroke volume variance, EVLW, blood velocity), although many of these measurements are derived from CO determination to begin with.

The monitoring of CO is considered The monitoring of CO is considered

to be very useful for proper to be very useful for proper

decision-making in critically ill and decision-making in critically ill and

high-risk surgical patients. high-risk surgical patients.

The fact that this statement is not The fact that this statement is not

supported by EBM tells us more supported by EBM tells us more

about the shortcomings of EBM than about the shortcomings of EBM than

those of the measurement of CO.those of the measurement of CO.

Bodies of two Air France passengers found CNN.COM June 6, 2009

The airline had failed to replace a part that monitors speed, as recommended by the manufacturer, based on technological

developments and improvements.

The Nexfin HD device (BMEYE, Amsterdam) uses a non-invasive, continuous blood pressure (BP) measurement (based on the Finapres method) to measure cardiac output continuously.

The Nexfin HD deviceThe Nexfin HD device

Stover JF, et al. BMC Anesthesiology 2009: 9: 6

Stover JF, et al. BMC Anesthesiology 2009: 9: 6

Importantly, there were no clinical signs of disturbed microcirculation of the fingers in these patients during application of the finger cuff, indicating a safe use of the Nexfin HD system.

The noninvasiveness of this technique allows to avoid complications related to more invasive techniques.

This new system is very easy to use and quickly to install within minutes…could offer a quick initial hemodynamic overview….on trend of MAP and CO. This would allow to bridge the time until a longer lasting invasive monitoring can be installed in the case of a deteriorating patient.

Comparison of Nexfin HD CO to PiCCO intermittent TTD CO

Pre CPBPre CPB

Post CPBPost CPB

Why do we need real-time CCO?Why do we need real-time CCO?

Intermittent TD CO measurements have a well known intrinsic limited reproducibility. This limitation makes them inferior to continuously measured real-time CO in assessing the response to therapeutic or diagnostic events with short time constants.

Fluid loading (e.g., periop. optimization)

Passive leg raising, end-exp. occlusion.

Immediate response to inotropes

Nexfin HD ApplicationsNexfin HD ApplicationsSyncope diagnostics - tilt table testing

Upon standing postoperatively, CO (Modelflow) declined by a mean of 1.4 L/min.

Conclusions: The early postoperative postural cardio-vascular response is impaired after radical prostatectomy with a risk of orthostatic intolerance, limiting early post-operative mobilization.

Will my patient respond to fluids?Yes. Give 1735 ml over 30 minutes.

““Will my patient Will my patient respond to fluids?”respond to fluids?”

Passive leg raising-induced changes in CO can reliably predict fluid responsiveness regardless of ventilation mode and cardiac rhythm.

Passive leg raising-induced changes in CO have a significantly higher predictive value than passive leg raising-induced changes in arterial pulse pressure.

The hemodynamic response to a 15-second end-expiratory occlusion can predict volume responsiveness in mechanically ventilated patients.

The accumulation of evidence showing that increasing DO2 in high-risk surgical patients may reduce morbidity and save lives has led Boyd and Bennett to claim that it may be considered unethical not to use goal-directed perioperative therapy once patient identification and the methods to be used in treating them are refined .

Unlike approaches that adopt a specific clinical practice, Unlike approaches that adopt a specific clinical practice, like liberal or restrictive fluid regimen, goal-directed like liberal or restrictive fluid regimen, goal-directed approaches employ various monitoring techniques and approaches employ various monitoring techniques and interventions in order to achieve interventions in order to achieve specificspecific end-points for end-points for selected parameters.selected parameters.

Cardiac index (CI)Cardiac index (CI)

Stroke volume (SV)Stroke volume (SV)

Oxygen delivery (DOOxygen delivery (DO22))

Mixed venous (SvOMixed venous (SvO22) or central venous ) or central venous

(ScvO(ScvO22) oxygen saturation) oxygen saturation

Lactate concentrationLactate concentration

pHi pHi

A bolus of 200 ml colloid (e.g., 6% HES 130/0.4) is administered over 2 min, and 5 min later the SV is assessed.

The procedure is repeated if there was an increase in SV of >10%. When the fluid bolus does not result in a SV increment >10%, optimization is regarded as achieved and surgery commenced.

Intermittent TD CO measurements have a well known intrinsic limited reproducibility which makes them

inferior to continuously measured real-time CO in the process of perioperative optimization.

Optimization – when and how?

Transesophageal Doppler ultrasound

Patient needs to be anesthetized

The Vigileo system

Patient needs to have an arterial line

The Nexfin HD

Totally non-invasive

Optimization – when and how?

NEXFINNEXFIN

CO (CI > 4.5 L/min/m2) and oxygen transport goals (DO2I ≥600 ml/min/m2) are important so direct flow monitoring should be implemented.

Fluids should be given to increase CO, and inodilators, such as dopexamine and dobutamine, added once the patient is no longer fluid (preload) responsive or not achieving the goals.

It is essential that the present individualized GDT approach includes optimization of flow-related parameters, such as cardiac stroke volume, within the limit of the individual patient’s cardiac capacity.

The concept is therefore different from the original Shoemaker concept for optimization, which used predetermined supra-physiologic values of cardiac index and DO2 as therapeutic goals.

The perioperative fluid The perioperative fluid

management strategy management strategy

determines the determines the

monitoring modality!monitoring modality!

The Nexfin HD-The Nexfin HD-

A truly non-A truly non-invasive CCO invasive CCO

monitormonitor

THANK YOU!THANK YOU!

Blood volume after fasting is normal, and a fluid-consuming third space has never been reliably shown.

The endothelial glycocalyx plays a key role and is destroyed not only by ischemia and surgery, but also by acute hypervolemia.

Undifferentiated fluid handling may increase the shift toward the interstitial space, the consequence being a positive fluid balance and weight gain of up to 10 kg, which may be related to severe complications.

Optimization ≠ Maximization

National Confidential Enquiry into Patient Outcome and Death.

1999 Report: Extremes of Age. http://www.ncepod.org.uk

National Confidential Enquiry into Perioperative Death have highlighted over-hydration as a contributory cause in the genesis of postoperative problems leading to death.

Carefully considered case histories have led to specific recommendations regarding careful fluid management (the implication being restriction) in vulnerable patients and those most at risk, such as the elderly.

A variety of metabolic endpoints are surrogate flow measurements, such as lactate, SvO2, ScvO2, which may be useful during resuscitation, but CO (CI > 4.5 L/min/m2) and oxygen transport goals (DO2I ≥600 ml/min/m2) are important so direct flow monitoring should be implemented.

Fluids should be given to increase CO, and inodilators such as dopexamine and dobutamine added once the patient is no longer fluid (preload) responsive or not achieving the goals.

A variety of metabolic endpoints are surrogate flow measurements, such as lactate, SvO2, ScvO2, which may be useful during resuscitation, but CO (CI > 4.5 L/min/m2) and oxygen transport goals (DO2I ≥600 ml/min/m2) are important so direct flow monitoring should be implemented.

Fluids should be given to increase CO, and inodilators such as dopexamine and dobutamine added once the patient is no longer fluid (preload) responsive or not achieving the goals.

This systematic review demonstrated a very poor relationship between CVP and blood volume as well as the inability of CVP / ΔCVP to predict the hemodynamic response to a fluid challenge.

CVP should not be used to make clinical decisions regarding fluid management.

Overall, only 56 ± 16% of 803 patients

that were included in the 24 studies

responded to a fluid challenge.

Perioperative fluid optimization Perioperative fluid optimization necessitates real-time CCOnecessitates real-time CCO

Intermittent TD CO measurements have a well known intrinsic limited reproducibility. This limitation makes them inferior to continuously measured real-time CO in assessing the response to therapeutic or diagnostic events with short time constants.

Fluid loading (e.g., periop. optimization)

Passive leg raising, end-exp. occlusion.

Immediate response to inotropes

Transesophageal Doppler ultrasound

Patient needs to be anesthetized

The Vigileo system

Patient needs to have an arterial line

The Nexfin HD

Totally non-invasive

LimitationsLimitations

1.1. Duration of measurement is restricted to 8 hoursDuration of measurement is restricted to 8 hours

2.2. Peripheral vasoconstriction (age, cold, vasopressors)Peripheral vasoconstriction (age, cold, vasopressors)

3.3. Edematous fingersEdematous fingers

4.4. Currently no PPV / SVVCurrently no PPV / SVV

5.5. GUI more suitable for a cardiology clinicGUI more suitable for a cardiology clinic

LimitationsLimitations

1.1. Duration of measurement is restricted to 8 hoursDuration of measurement is restricted to 8 hours

2.2. Peripheral vasoconstriction (age, cold, vasopressors)Peripheral vasoconstriction (age, cold, vasopressors)

3.3. Edematous fingersEdematous fingers

4.4. Currently no PPV / SVVCurrently no PPV / SVV

5.5. GUI more suitable for a cardiology clinicGUI more suitable for a cardiology clinic

Additional benefitsAdditional benefits

1.1. Semi-disposable finger cuffSemi-disposable finger cuff

2.2. Touch screenTouch screen

3.3. Instant data retrieval with DOKInstant data retrieval with DOK

Boulain T, et al. Chest 2002; 121:1245–52

Monnet X, et al. Crit Care Med 2006; 34:1402-7

Lafanechere A, et al. Crit Care 2006; 10:R132

Lamia B, et al. Intensive Care Med 2007; 33:1125–32

Maizel J, et al. Intensive Care Med 2007; 33:1133–8

Caille V, et al. Intensive Care Med 2008; 34:1239–45

Thiel SW, et al. Crit Care 2009;13:R111

Biais M, et al. Crit Care 2009, 13:R195

Prediction of volume responsiveness by using passive leg raising

Changes in stroke volume, radial pulse pressure, and peak velocity of femoral artery flow induced by passive leg raising are accurate and interchangeable indices for predicting fluid responsiveness in non-intubated patients with severe sepsis or acute pancreatitis.

13 patients were studied within 2 h of arrival in the ICU following CABG or mitral valve reconstruction.

Cardiac output (CO) was evaluated using the FloTrac (COed), the modified Modelflow (COmf ), and the ultra-sound HemoSonic system (COhs), and compared with thermodilution (COtd) as the reference (triplicate, automated system under computer control, equally spread measurements over the ventilatory cycle).

104 paired CO values were assessed before, during and after four interventions: (i) an increase of tidal volume by 50%; (ii) a 10 cm H2O increase in PEEP; (iii) passive leg raising; (iv) head up position.

COmf has best

precision (0.69

l/min) and smallest

range of the limits

of agreement (-1.08–

1.68 l/min), 26%,

compared with the

COed and COhs

(-1.47–2.13), 34%,

and (-2.62–1.80

l/min), 44%,

respectively.

FloTrac–Vigileo (COed)

Modified Modelflow method

(COmf)

HemoSonic 100ultrasound system

(COhs)

Our main finding is that only he modified Modelflow yields limits of agreement (26%) that are below the 30% criteria for a theoretically acceptable alternative to thermodilution cardiac output.

Monitoring changes or trends in cardiac output can be performed reasonably well with the Modelflow and the HemoSonic, while the FloTrac performs less well in this regard.

Encouraged by the simplicity of setup procedure and advantage for the patient, we suggest future work focuses on the Modelflow system.