100% noninvasive dynamic assessment of fluid responsiveness
Cheetah’s noninvasive hemodynamic monitoring technology, directly, noninvasively and accurately measures a patient’s cardiovascular response to a fluid volume challenge.
DYNAMIC ASSESSMENT METHODS
Will additional IV fluid increase cardiac output and perfusion?
Dynamic assessment of a patient’s fluid responsiveness, by directly challenging the patient with pre-determined fluid volumes and monitoring the heart’s response, is the clinically preferred approach to answer this question.
Dynamic measures of cardiac output may improve volume management by providing direct, continuous, and noninvasive measures of the change in the stroke volume index (ΔSVI). A ΔSVI ≥ 10% is highly predictive of a significant increase in cardiac output in response to additional fluid, consistent with Starling’s Law of the Heart.
Two dynamic assessment methods are used to determine fluid responsiveness. Both the passive leg raise (PLR) technique, and the fluid bolus (FB) challenge, when used in conjunction with Cheetah’s noninvasive hemodynamic monitoring technology, provide real-time quantification of a patient’s fluid responsiveness.
Watch the Dynamic Assessments Animation Video for an overview of Dynamic Assessment methods, and how they are used to challenge the heart with volume to measure its ability to respond.
The PASSIVE LEG RAISE procedure translocates 250-300 cc of blood from lower extremities into the heart, providing a reversible challenge of the heart’s response to increased fluid load.
The Passive Leg Raise Video, presented by acclaimed critical care physicians Dr’s. Monett and TeBoul, describes the challenges of fluid administration, why to perform a PLR and how to perform it. The video captures an actual PLR dynamic assessment using the Cheetah Medical Starling SV system to noninvasively collect and report the hemodynamic data, including stroke volume, cardiac output, and total peripheral resistance.
The FLUID BOLUS CHALLENGE approach involves the non-reversible IV administration
of 250-300 cc of fluid to challenge the heart’s response. The optimal parameter to assess a fluid challenge response is the change in stroke volume index (ΔSVI), as it measures the actual stroke volume leaving the left ventricle with each heartbeat. Cheetah’s hemodynamic monitoring systems provide noninvasive, direct measurements of cardiac output, while other technologies derive cardiac output indirectly from associated pressure variations that are dependent on respiratory variations, with stroke volume variation (SVV) as the main unit of measure.
Employing either a passive leg raise or a fluid bolus challenge and using Cheetah technology to directly and noninvasively measure and compare the SVI before and after the challenge, a patient’s fluid responsiveness can be determined with a high degree of sensitivity and specificity. If the change in SVI is ≤ 9% from baseline SVI, evidence shows that the patient is not likely to be fluid responsive.
The response can be visualized by examining a rendition of the Starling Curve. Fluid responsive patients are observable on the steep part of the curve. Patients who are not fluid responsive are at, or near, the flat part of the curve.
Positive test: ΔSVI ≥ 10%: Patient is likely to be fluid responsive.1
Negative test: ΔSVI < 10%: Patient is not likely to be fluid responsive.1
Note: A positive fluid response is only one clinical metric that should be considered to determine if fluid administration to a patient is indicated. A positive assessment of fluid responsiveness only indicates that the patient is capable of responding to fluids, by increasing stroke volume at the particular time of the assessment.
Many organizational acknowledgements support the use of dynamic assessments as a fluid management tool. Key organizations such as CMS and ESICM, the Surviving Sepsis campaigns, and the ERAS and PSH care pathways and protocols support the use of dynamic assessments for guided fluid therapy.
Download the Dynamic Assessments of Fluid Responsiveness Brochure here. Also available from the Guides and Tools page
1. Cecconi M et al. What is a fluid challenge? Curr Opin Crit Care 2011; 17: 290-295.