Give fluid only if the patient is likely to respond and needs more cardiac output. Use passive leg raise or a mini fluid challenge with a cardiac output surrogate, and stop when the response is lost or harm appears.
At the bedside
Timed steps- 1
Ask three questions
Before each bolusDoes the patient need more cardiac output (hypoperfusion)? Will they respond (preload responsive)? Is it safe (lungs, abdomen, RV)?
- 2
Passive leg raise (PLR)
TestStart semi-recumbent 45°, then lower trunk flat and raise legs 45° for 60-90 s. A rise in cardiac output or VTI ≥ 10% predicts response (pulse pressure change is less reliable).
- 3
Mini fluid challenge
Alternative100-250 mL over 1-2 min with LVOT VTI measured on echo; ≥ 10% rise suggests responsiveness.
- 4
Dynamic indices
Alternative (controlled ventilation)Pulse pressure variation > 12-13% on Vt ≥ 8 mL/kg in sinus rhythm with no spontaneous effort; end-expiratory occlusion test (15 s) ≥ 5% rise in CO.
- 5
Fluid challenge
Give250-500 mL balanced crystalloid over 10-15 min. Reassess perfusion and the targets after each bolus.
- 6
Stop when
StopNo longer responsive, perfusion normalised, or signs of harm (rising O2 need, B-lines, IVC plethoric, intra-abdominal hypertension, venous congestion on VExUS).
Tests of fluid responsiveness and their limits
| Test | Positive if | Does not work when |
|---|---|---|
| Passive leg raise (with CO measure) | CO or VTI rises ≥ 10% | Intra-abdominal hypertension, leg amputation, raised ICP (relative) |
| Pulse pressure variation | > 12-13% | Spontaneous breathing, arrhythmia, Vt < 8 mL/kg, low compliance, open chest |
| End-expiratory occlusion | CO rises ≥ 5% with 15 s hold | Patient cannot tolerate 15 s pause |
| Mini fluid challenge (100 mL) | VTI rises ≥ 10% | Poor echo windows; measurement error close to threshold |
| CVP alone | Not recommended | Static CVP poorly predicts response |
References
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Should I give more fluid?
Step 1 of ~3
Decision: Signs of hypoperfusion still present?
Based on Cecconi M, De Backer D, Antonelli M, et al; Monnet X, Marik P, Teboul JL. Educational use; follow local protocol.
Pathophysiology
On the steep part of the Frank-Starling curve, preload increases stroke volume; on the flat part it only raises venous pressure and causes oedema. Only about half of haemodynamically unstable ICU patients are fluid responsive.
Evidence
- Monnet 2016 meta-analysis: PLR-induced CO change had pooled sensitivity 85% and specificity 91% (threshold ~10%); PLR-induced pulse pressure change was less accurate.
- SSC 2026: suggests dynamic measures (passive leg raise or a fluid bolus with stroke volume, SVV, pulse pressure or PPV) over physical examination or static measures alone (conditional, low certainty). After 30 mL/kg in septic shock, either a liberal or a restrictive strategy is acceptable.
Controversies
- Whether fluid restriction after initial resuscitation improves outcome (CLOVERS and CLASSIC showed no difference; see module 4).
🇮🇳 India notes
- Without cardiac output monitors, use LVOT VTI on echo, or ETCO2 during PLR in ventilated patients; both are cheap.
References
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Test yourself
Module quiz · score 70% to complete the module
Educational reference for trained clinicians. Check doses against your hospital protocol and the patient in front of you.