Assessing  Preload  Responsiveness     Page  1  

Assessing Preload Responsiveness Using Arterial Pressure Based Technologies

Patricia A. Meehan, RN, MS

Education Consultant Edwards Lifesciences, LLC

Content Description : Fluid administration is a first line intervention for patients with an unstable cardiovascular status. Two major problems exist with this intervention: only one-half of the patients who receive fluid respond favorably, and standard static parameters such as CVP and PAWP do not reliably assess the response to fluid. This session describes the technology and applications of using the arterial pressure for cardiac output monitoring and the implications of using stroke volume variation and passive leg raising maneuvers as methods of assessing fluid responsiveness. Learner Objectives: Upon completion of this session, the participant will be able to: 1. Define technologies and associated parameters used to assess preload. 2. Describe maneuvers to assess preload responsiveness. 3. Incorporate dynamic fluid assessment parameters in a preload optimization algorithm. Outline: I. Arterial Pressure Based Technologies A. Basic premises 1. Arterial pulse waveform or pulse pressures is proportional to stroke volume, inversely related to aortic compliance 2. Arterial pulsations reflect heart rate: HR x SV = CO 3. Aortic large vessel compliance compensation: input age, gender, height and weight 4. Peripheral vascular resistance compensation: waveform assessment

B. Different Methods: Overall Comparisons 1. Pulse Contour: PiCCO 2. Pulse Power: LiDCO 3. Arterial Pulse Pressure (APCO): FloTrac a. uses standard deviation of full arterial pressures and waveform analysis b. does not require external calibration

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C. Concerns and Potential Limitations 1. Factors affecting arterial pressure monitoring Set up, components, priming Proper leveling, zeroing Square Wave Test 2. Potential concerns with irregular heart rate: issue of accuracy vs reproducibility 3. Concerns with additional calibration II. Arterial Pressures: Providing More Than Blood Pressure

Physiology of Stroke Volume Variation

1. Relationship of intra-thoracic pressures to arterial pressures

2. Starling Curve for preload responsiveness

Patient A is preload responsive: • On steep part or fluid responsive portion • Fluid bolus results in significant increase in SV Patient B is not preload responsive: • On plateau portion of curve • No preload recruitibility • Same bolus volume does not result in significant

increase in SV

C. Indications: 1. Evaluate the response to fluid interventions

2. Determine or predict the patient’s potential response to fluid therapy 3. Significance: Greater the SPV, PPV, SVV the greater the predicted response to fluid loading Dynamic Parameters

Parameter Normal Fluid Responsive SPV mmHg 5 mmHg >10 mmHg PPV % < 13% >13% SVV % <10 – 15 % > 10 - 15%

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D. Limitations 1. Intubated and with controlled ventilation 2. Fixed tidal volume and respiratory rate

3. Irregular rhythms may produce varied results 4. Physiologic conditions: Vasodilator therapy Increased Juxtacardiac pressures: PEEP, Cardiac Tamponade, Pneumothorax III. Maneuvers to assess preload responsiveness

A. Passive Leg Raising Supine Raise legs up 45 degrees 4 minutes 150 – 300 ml increase in Venous return PASSIVE FLUID CHALLENGE

B. Valsalva Maneuver C. Altering Tidal Volume

SVV:  Pre  and  Post  PLRPre - PLR SVV 18 %

SV 46CO/CI 3.9/2.0

Post - PLR SVV 9 %

SV 63CO/CI 5.7/3.0

Simulated data

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IV. Clinical Indications/Applications A. Traditional Hemodynamic Parameters Used to Assess Fluid Status 1. Blood Pressure: Issues/ Limitations 2. Pressure Based parameters: Issues and current research a. Issues: CVP and PAOP poor predictors of fluid status b. Current Research: Kumar CCM 2004, Osman CCM 2007 B. SPV, PPV, SVV are overall better predictors of fluid responsiveness.

C. Relationship between SV and SVV

Does  P  =  F?  

Components  of  the  Arterial  Pulse

Arterial SV

Arterial Tone:ComplianceResistance

PP SV

SBP

DBP

JMHeadley ©2005

Dicrotic notch

MAP

CO

Art. SVR

Stroke  Volume:  Preload,  Afterload,  Contractility  

• Issues  Surrounding  Pressure  Based  Parameters  for  Preload  

• RAP/CVP  =  RVEDP  =  RVEDV  =  RV  PRELOAD• PAD  =  PAWP  =  LAP  =  LVEDP  =  LVEDV  =  LV  PRELOAD

Altered Ventricular Compliance

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Trend over time of SV and SVV. Note that when the SV is high the SVV is low. When SVV is increasing the SV decreases.

McGee 2006 Crit Care Med suppl. Abs 227

D. Decision trees using SVV to optimize cardiac performance

E. Case Scenario: Post –operative fluid management

Does  this  Patient  NEED  Fluid??

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F. Is this patient going to respond to fluid? Spontaneously Breathing patient

Overall Trend of SVV was higher than target of approx. 10%. CO and SV values were low.2:27 pm Patient given 1 unit of packed red blood cells and a fluid challenge of 500 ml of normal saline.

After fluid resuscitation, the SVV values decreased with a corresponding increase in both SV and CO. Note the SVV at 2:32 pm. The value of 25 was a result of the patient experiencing an arrhythmia at that time. However, the overall trend was now within the target range.

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Selected References:

1. Headley JM. Clinically Relevant Monitoring Using Arterial Pressure-based Technologies

and Stroke Volume Variation to Assess Fluid Responsiveness. AACN NTI News 2007:May 20-21. 1-7. http://www.ntinewsonline.org/SM/SM_CE.htm

2. Headley JM. Arterial Pressure-Based Technologies: A New Trend in Cardiac Output Monitoring. Crit Care Nurs Clin N Am, 2006:18:179-187.

3. Kumar A, Anel R, Bunnell E, Habet K, Zanotti S, Marshall S, et al. Pulmonary artery occlusion pressure and central venous pressure fail to predict ventricular filling volume, cardiac performance, or the response to volume administration in normal subjects. Crit Care Med. 2004; 32:691–699.

4. McGee WT, Horswell JL, Hatib FS, Headley JM. (2006) Stroke volume variation to stroke volume relationship using a less invasive arterial pressure based technology. Crit Care Med. 2006;34 (12) suppl. A60 Abs. 227.

5. Michard F. Changes in Arterial Pressure during Mechanical Ventilation. Anesth. 2005;103:419-428.

6. Osman D, Ridel C, Ray P, Monnet X, Anguel A, Richard C, Teboul J-L. Cardiac filling pressures are not appropriate to predict hemodynamic response to volume challenge. Crit Care Med. 2207;35(1):64-68.

7. Parry-Jones AJD, Pittman JAL. Arterial pressure and stroke volume variability as measurements for cardiovascular optimization. Int J Intensive Care 2003; 10:67-72.:49-50.

8. Pinsky MR. Probing the Limits of Arterial Pulse Contour Analysis to Predict Preload Responsiveness. Anesth Analg. 2003;96:1245-1247.

9. Reuter DA, Goetz AE. Arterial Pulse Contour Analysis: Applicability to Clinical Routine in Functional Hemodynamic Monitoring: eds MR Pinsky and D. Payen. Update in Intensive Care and Emergency Medicine 42. Springer- Verlag. New York. 2005: 175-181.

10. Teboul J-L. Dynamic concepts of volume responsiveness. Int J Intensive Care 2003:49-50.

11. www. AACN.org 12. www. Edwards.com

Speaker Contact: Patricia_Meehan@Edwards.com