💧 Fluid Responsiveness Assessment
Dynamic fluid-responsiveness assessment to guide whether further fluids will increase cardiac output.
Clinical takeaway
PPV/SVV is only valid with controlled mechanical ventilation (Vt ≥ 8), sinus rhythm, and no spontaneous breathing — otherwise use PLR or a fluid challenge (original synthesis · not guideline verbatim).
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When to use
Use during resuscitation to test responsiveness via passive leg raise, fluid challenge, or PPV/SVV before giving more fluid.
How it works
Passive leg raise or 250–500 mL fluid challenge increasing stroke volume/cardiac output ≥ 10%, or PPV/SVV > 13% (with applicability conditions), indicates fluid responsiveness; dynamic indices outperform static CVP.
Key points
- PPV/SVV is only valid with controlled mechanical ventilation (Vt ≥ 8), sinus rhythm, and no spontaneous breathing — otherwise use PLR or a fluid challenge (original synthesis · not guideline verbatim).
- Responsiveness alone does not mandate fluids; give them only with concurrent signs of hypoperfusion.
- Static CVP predicts fluid responsiveness poorly and should not drive fluid decisions.
References
- Monnet X, Teboul JL. Passive leg raising. Intensive Care Med 2015.
- Surviving Sepsis Campaign 2021 — dynamic measures.
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Assessment method | Passive leg raise (PLR, measure SV/CO change) |
|---|---|
| Value (PLR/challenge = SV or CO increase %; PPV/SVV = variation %) | 12 % |
| PPV/SVV applicability (mechanical ventilation Vt ≥ 8, sinus rhythm, no spontaneous breathing, no right-heart failure/intra-abdominal hypertension) | Met (or not a PPV/SVV method) |
→Fluid responsivenessResponsive
- Determination：Passive leg raise produced a stroke-volume/cardiac-output increase of 12% (threshold ≥ 10%) → fluid-responsive (a fluid bolus may increase cardiac output)
- Management direction：With evidence of hypoperfusion (high lactate/oliguria/prolonged CRT), give fluids cautiously and reassess; stop volume expansion once non-responsive or perfusion improves
- Note：Dynamic indices outperform static (CVP/single pressure predicts poorly). PLR and fluid challenge directly measure SV/CO change and remain applicable with spontaneous breathing and arrhythmia; PPV/SVV requires mechanical ventilation Vt ≥ 8, sinus rhythm, no spontaneous breathing, no right-heart failure/intra-abdominal hypertension. Give fluids on this basis only with signs of hypoperfusion
| Assessment method | PPV / SVV (pulse-pressure / stroke-volume variation) |
|---|---|
| Value (PLR/challenge = SV or CO increase %; PPV/SVV = variation %) | 12 % |
| PPV/SVV applicability (mechanical ventilation Vt ≥ 8, sinus rhythm, no spontaneous breathing, no right-heart failure/intra-abdominal hypertension) | Not met |
→PPV/SVVUnreliable
- Determination：PPV/SVV is reliable only with mechanical ventilation (Vt ≥ 8 mL/kg), sinus rhythm, no spontaneous breathing trigger, and no severe right-heart failure/intra-abdominal hypertension; the current conditions are not met
- Recommendation：Switch to passive leg raise (PLR) or fluid challenge (directly measuring stroke-volume/cardiac-output change), which remain applicable with spontaneous breathing/arrhythmia
- Basis：Dynamic indices outperform static (CVP predicts poorly); PPV/SVV applicability conditions
Frequently asked questions
- What is Fluid Responsiveness Assessment?
- Dynamic fluid-responsiveness assessment to guide whether further fluids will increase cardiac output.
- How is Fluid Responsiveness Assessment calculated? What is the core formula?
- Passive leg raise or 250–500 mL fluid challenge increasing stroke volume/cardiac output ≥ 10%, or PPV/SVV > 13% (with applicability conditions), indicates fluid responsiveness; dynamic indices outperform static CVP.
- When is Fluid Responsiveness Assessment used?
- Use during resuscitation to test responsiveness via passive leg raise, fluid challenge, or PPV/SVV before giving more fluid.
- What are the key clinical points for Fluid Responsiveness Assessment?
- PPV/SVV is only valid with controlled mechanical ventilation (Vt ≥ 8), sinus rhythm, and no spontaneous breathing — otherwise use PLR or a fluid challenge (original synthesis · not guideline verbatim). Responsiveness alone does not mandate fluids; give them only with concurrent signs of hypoperfusion. Static CVP predicts fluid responsiveness poorly and should not drive fluid decisions.
- What are the limits and cautions when using Fluid Responsiveness Assessment?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is Fluid Responsiveness Assessment calculated in practice? Can you show a worked example?
- Inputs: Assessment method Passive leg raise (PLR, measure SV/CO change), Value (PLR/challenge = SV or CO increase %; PPV/SVV = variation %) 12 %, PPV/SVV applicability (mechanical ventilation Vt ≥ 8, sinus rhythm, no spontaneous breathing, no right-heart failure/intra-abdominal hypertension) Met (or not a PPV/SVV method) → Result: Fluid responsiveness Responsive（Determination: Passive leg raise produced a stroke-volume/cardiac-output increase of 12% (threshold ≥ 10%) → fluid-responsive (a fluid bolus may increase cardiac output), Management direction: With evidence of hypoperfusion (high lactate/oliguria/prolonged CRT), give fluids cautiously and reassess; stop volume expansion once non-responsive or perfusion improves, Note: Dynamic indices outperform static (CVP/single pressure predicts poorly). PLR and fluid challenge directly measure SV/CO change and remain applicable with spontaneous breathing and arrhythmia; PPV/SVV requires mechanical ventilation Vt ≥ 8, sinus rhythm, no spontaneous breathing, no right-heart failure/intra-abdominal hypertension. Give fluids on this basis only with signs of hypoperfusion） Inputs: Assessment method PPV / SVV (pulse-pressure / stroke-volume variation), Value (PLR/challenge = SV or CO increase %; PPV/SVV = variation %) 12 %, PPV/SVV applicability (mechanical ventilation Vt ≥ 8, sinus rhythm, no spontaneous breathing, no right-heart failure/intra-abdominal hypertension) Not met → Result: PPV/SVV Unreliable（Determination: PPV/SVV is reliable only with mechanical ventilation (Vt ≥ 8 mL/kg), sinus rhythm, no spontaneous breathing trigger, and no severe right-heart failure/intra-abdominal hypertension; the current conditions are not met, Recommendation: Switch to passive leg raise (PLR) or fluid challenge (directly measuring stroke-volume/cardiac-output change), which remain applicable with spontaneous breathing/arrhythmia, Basis: Dynamic indices outperform static (CVP predicts poorly); PPV/SVV applicability conditions）