Trigger Points and Concerns
The decision tree was developed to be used in conjunction with flow measurements using the oesophageal 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 analysing 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 prioritised
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/hr
- Low Cardiac Output State
- 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/m²
- Low Stroke Volume: significantly below ‘normal’ e.g. SV < 50-70 mL, SVI < 30 mL
Supplementary Clinical Indicators
- Hypertension: e.g. Systolic > 180mmHg, 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 Conscious Level: any deterioration rather than a score