Murray lung injury score
Severity of acute lung injury from chest X-ray, oxygenation, PEEP and compliance
Sources last checked: 2026-10-13
Murray lung injury score
Severity of acute lung injury from chest X-ray, oxygenation, PEEP and compliance
Largely superseded for diagnosis by the Berlin and 2024 global definitions; still used for trial entry and ECMO referral. Chest X-ray quadrant scoring has substantial inter-observer variability.
Interpretation
| 0 — no lung injury | |
|---|---|
| 0.1–2.5 — mild to moderate lung injury | Murray 1988 category for acute lung injury short of the severe range. |
| > 2.5 — severe lung injury (ARDS) | Murray 1988 category for severe lung injury. LIS > 3 has been used as an entry criterion for ECMO referral in trials. |
What is the Murray lung injury score?
The Murray lung injury score (LIS) grades acute lung injury from four components, each scored 0–4: chest X-ray consolidation by quadrant, PaO₂/FiO₂, PEEP and respiratory system compliance. The total is divided by the number of components used. Murray and colleagues proposed it in 1988 to give ARDS a graded, multidimensional definition.
When to use it
- Screening for referral to an ECMO centre, where LIS > 3 has been used as an entry criterion
- Describing the severity of lung injury in research or audit
- Following the course of lung injury over days in ventilated patients
When not to use it
- To diagnose ARDS — use the Berlin or 2024 global definition
- When chest imaging is not interpretable (e.g. large effusions, poor-quality supine film) without acknowledging the uncertainty
How it is calculated
Each component scores 0–4 (chest X-ray quadrants, PaO₂/FiO₂, PEEP, compliance). LIS = sum of the components used ÷ number of components used (PEEP and compliance are left out when not available).
Clinical pearls and limitations
- Largely superseded for diagnosis by the Berlin and 2024 global definitions; still used for trial entry and ECMO referral. Chest X-ray quadrant scoring has substantial inter-observer variability.
- PEEP and compliance count only in ventilated patients; leave them out otherwise and the score is averaged over the remaining components.
- Compliance is static respiratory system compliance: tidal volume ÷ (plateau pressure − PEEP).
- A score above 2.5 marked severe lung injury in the original description.
- Higher LIS correlates with Berlin severity; in a 550-patient cohort it predicted mortality about as well as, but not better than, the Berlin stages.
Frequently asked questions
What Murray score is needed for ECMO?
Trials and referral criteria such as CESAR used LIS > 3 (or uncompensated hypercapnic acidosis). Local ECMO network criteria vary, so check your referral pathway.
How is the Murray score calculated?
Score each available component 0–4 and divide the sum by the number of components used. For example 4 + 4 + 3 + 3 = 14 over 4 components gives 3.5.
What does a Murray score of 0.1–2.5 mean?
Mild-to-moderate lung injury in the original classification; 0 is no injury and above 2.5 is severe injury.
Is the Murray score still used?
Rarely for diagnosis, but it remains common in ECMO referral criteria and as an outcome measure in trials.
Evidence and guidelines
- Primary source: Murray JF, Matthay MA, Luce JM, Flick MR. An expanded definition of the adult respiratory distress syndrome. Am Rev Respir Dis 1988;138(3):720-723 (erratum 1989;139:1065).
- Kangelaris KN, Calfee CS, May AK, et al. Is there still a role for the lung injury score in the era of the Berlin definition ARDS? Ann Intensive Care 2014;4:4 — reproduces the component table.
- Consensus statements on the utility of defining ARDS and of past and current definitions. BMJ Open 2024;14:e082986 — LIS table and 2.5 cut-off.
Have a follow-up question?
Medelix answers clinical questions from current guidelines and studies — every statement with its source.
Ask Medelix about the Murray lung injury scoreRelated calculators
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- Predicted body weight & protective tidal volumeTidal volume in mL from predicted body weight (ARDSNet formula) for lung-protective ventilation
- APACHE IIICU severity of illness from the worst values in the first 24 hours
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