What is a recommended external bedside examination to determine fluid responsiveness in a low-resource setting?

Passive Leg Raise Test for Fluid Responsiveness Assessment

In low-resource settings, the passive leg raise (PLR) test is the recommended bedside examination to determine fluid responsiveness, as it requires no equipment beyond clinical assessment or basic monitoring and has been extensively validated across multiple guidelines.

Why Passive Leg Raise is Optimal for Low-Resource Settings

The PLR test functions as a reversible, endogenous fluid challenge that mobilizes approximately 300 mL of blood from the lower extremities to the thorax, increasing preload without actually administering fluid 1. This makes it ideal when advanced monitoring is unavailable.

Technique and Interpretation

The PLR maneuver involves:

• Moving the patient from a semirecumbent position (head elevated) to supine while simultaneously raising the legs to 45° for 3 minutes 2, 3
• Observing for hemodynamic improvement during this period 1

Positive response indicators include:

• Improvement in blood pressure or heart rate 1
• Improved capillary refill and skin temperature 4
• Decreased mottling and improved mental status 4
• Increased urine output 4

Evidence Supporting PLR in Resource-Limited Settings

The British Journal of Anaesthesia meta-analysis of 2,260 patients demonstrated that PLR strongly predicts fluid responsiveness with a positive likelihood ratio of 11 (95% CI 7.6-17) and pooled specificity of 92% 1. Critically, only 50% of hypotensive patients actually respond to fluid, making this test essential to avoid inappropriate fluid administration 1.

The Surviving Sepsis Campaign guidelines emphasize that dynamic measures like PLR have superior diagnostic accuracy compared to static measurements (such as central venous pressure) for predicting fluid responsiveness 1. Static measures cannot reliably predict who will benefit from fluid 1.

Recent Validation in Low-Resource Settings

A 2025 study from Bangladesh specifically validated PLR using the perfusion index (PI) in resource-limited settings, demonstrating good accuracy (AUROC 0.87,95% CI 0.75-0.99) at baseline in patients with sepsis and severe malaria 5. The test showed high sensitivity and negative predictive value, making it particularly useful for ruling out fluid responsiveness 5.

Practical Implementation Without Advanced Monitoring

When ultrasound or cardiac output monitors are unavailable:

• Assess clinical parameters before and during PLR: blood pressure, heart rate, capillary refill time, skin perfusion, mental status 1, 4
• A sustained improvement in these parameters during the 3-minute PLR suggests fluid responsiveness 1
• If no improvement occurs, the hypotension is likely due to inadequate vascular tone or cardiac contractility rather than hypovolemia, and vasopressors or inotropes should be considered instead of fluid 1

With basic pulse oximetry:

• Monitor perfusion index changes if available on the device 5
• A PI increase ≥9.7% during PLR predicts fluid responsiveness 5

Critical Limitations to Recognize

PLR may be unreliable in:

• Patients with intra-abdominal hypertension, where it cannot predict fluid responsiveness 1
• Patients with abdominal compartment syndrome 1

Important caveats:

• The Critical Care Medicine guidelines make no specific recommendation for IVC diameter/collapsibility in spontaneously breathing patients due to lack of consensus on methodology 1
• Do not delay obvious fluid resuscitation in clearly hypovolemic patients to perform PLR testing—clinical judgment supersedes any test 1
• The test is most valuable when volume status is uncertain 1

Alternative When PLR Cannot Be Performed

If PLR is contraindicated (e.g., leg fractures, increased intracranial pressure), consider a small fluid challenge of 250-500 mL over 10-15 minutes with careful clinical reassessment 1, 4. However, this actually administers fluid and cannot be reversed, making it less ideal than PLR 2.

Integration Into Clinical Algorithm

1. Identify hypotensive patient with suspected hypovolemia 1
2. Perform focused assessment: heart rate, blood pressure, capillary refill, skin perfusion, mental status, urine output 1, 4
3. Execute PLR test if volume status uncertain 1, 2
4. If PLR positive (clinical improvement): administer fluid bolus 1
5. If PLR negative (no improvement): consider vasopressors or inotropes rather than additional fluid 1
6. Reassess after each intervention 1, 4

This approach prevents the common error of administering fluid to the approximately 50% of hypotensive patients who will not benefit and may be harmed by volume overload 1.