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Decision Tree

Overview of the Decision Tree


The esophageal Doppler monitor (EDM+),  was developed as a relatively non-invasive, but extremely precise method of measuring cardiac output. Although initially developed as a less invasive alternative to the pulmonary artery catheter, from its early inception it was recognised that the technology is uniquely adept at driving flow based treatment algorithms. Doppler guided fluid management protocols have been proven to improve outcomes in a variety of patient groups.

Doppler guided stroke volume optimization has been proven in several clinical outcome studies to be beneficial to patients. It is also clear that both excessive fluid volumes and inadequate volume are extremely detrimental to patient outcome. The decision tree is a consolidation of this evidence base and the use of vasoactive and inotropic interventions as part of a global hemodynamic protocol.

An expert panel of senior clinicians reviewed the available evidence and agreed on a rational approach to using Doppler flow based measurements to guide therapy. The decision tree considers patients both perioperatively and in critical care.

Using the Decision Tree

Navigation is by a series of Yes/No boxes. Commands are in blue boxes and questions are in gray boxes. Please note that caveats are presented which may lead to an alternative pathway. Caveats are in a red box with red pathways. Caveats should be ignored if inappropriate to the patient.

A good understanding of cardiovascular physiology is important. Ensure optimal focus is obtained before interpretation of data.

Visit the Decision Tree website:

Trigger Points and Concerns

The decision tree was developed to be used in conjunction with flow measurements using the esophageal Doppler monitor.

A good understanding of cardiovascular physiology is essential, including preload, afterload and contractility. Always ensure optimal focus of the Doppler probe is achieved before analyzing the data.

NOTE – These trigger points and concerns:​

        • Should not be assessed in isolation.
        • Are not the same as physiological targets
        • Are indicative and not absolute
        • Are not prioritized

Primary Clinical Indicators

        • Hypotension: e.g. Systolic < 100 mmHg, MAP < 60 -70 mmHg or a clinically significant drop in MAP – e.g. 30 – 40 mmHg from assumed ‘normal’ or baseline
        • Tachycardia: e.g. > 90 bpm
        • Oliguria: < 0.5 ml/kg/h
        • Low Cardiac Output State ​​

Flow Indicators

        •  Reduced FTc: < 330 ms or considered low for clinical condition e.g. any high resistant state
        •  Low Cardiac Output: significantly below ‘normal’ e.g. CO < 4– 6 L, CI < 2.5 L/min/m​²
        •  Low Stroke Volume: significantly below ‘normal’ e.g. SV < 50 – 70 ml, SVI < 30 ml

Supplementary Clinical Indicators

        •  Hypertension: e.g. Systolic > 180 mmHg or > 30 – 40 mmHg above baseline
        •  Lactate: > 2 mmol/L
        •  Base Excess: -3 or +3 mEq/L​
        •  Peripheral Shutdown: – Looks ‘unwell’ e.g. pale, sweaty or a clinical picture of poor perfusion
        •  SaO2: < 93% or having to increase FiO2 by 20% to maintain sats.
        •  ​Low ScVO2: < 65 – 70%
        •  Reduced Consciousness Level: any deterioration rather than a score​


        • Temperature
        •  DO2
        •  CVP
        •  SVR
        •  ​SVV/PPV

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