Acute Lung Injury Murray Score

Evaluates cases of severe acute respiratory failure to check the need for extracorporeal membrane oxygenation (EMCO) instead of ventilation.

In the text below the calculator there is more information about the scoring method.

The Murray score assess the status of patients with severe respiratory failure (caused by acute lung injury), in order to determine whether extracorporeal membrane oxygenation is required, as opposed to ventilation.

This scoring model is based on value of hypoxemia, positive end-expiratory pressure, compliance and number of CXR quadrants infiltrated.

Murray scores of 3 and above (≥2.5 if rapid deterioration) carry indication of ECMO.

The result from the Murray scoring system is interpreted in terms of severity of lung injury as follows:

■ 0 points – no lung injury;

■ 1 to 2.5 points – mild to moderate lung injury;

■ ≥5 points – severe lung injury, acute respiratory distress syndrome.


Hypoxemia PaO2/FiO2


PEEP (cmH2O)


Compliance (ml/cmH2O)


CXR quadrants infiltrated

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The scoring method explained

This is an evaluation model created by Murray et al. that is addressed to cases of severe adult respiratory failure in which the clinician might need help deciding whether the patient should be referred for conventional ventilation or extracorporeal membrane oxygenation (ECMO).

ARF is a known high mortality condition and the rapid initiation of ECMO in eligible cases can help reduce mortality risk in some cases.

The Murray score is based on four different pulmonary variables, as described in the following table:

Murray score item Description
Hypoxemia PaO2/FiO2 Measured in mmHg on 100% oxygen for at least 20 minutes. This, with hypercapnia are the main clinical triggers for using ECMO.
PEEP in cmH2O The positive end-expiratory pressure, measurable in patients already under ventilation.
Compliance in mL/cmH2O Calculated as the ratio between tidal volume in mL and PIP– PEEP.
CXR quadrants infiltrated Alveolar consolidation in how many quadrants, as seen on x-ray.

The main treatment option in the case of patients diagnosed with acute respiratory failure consists in ventilation, treatment with steroids, bronchoscopy or nitric oxide.


Result interpretation

Each of the 4 criteria in the Murray score is awarded a number of points from 0 to 4, as per the following table:

 Item / No. of points 0 1 2 3 4
Hypoxemia PaO2/FiO2 ≥300 225 – 299 175 – 224 100 – 174 <100
PEEP (cmH2O) ≤5 6 – 8 9 – 11 11 – 14 ≥15
Compliance (ml/cmH2O) ≥80 60 – 79 40 – 59 20 – 39 ≤19
CXR quadrants infiltrated 0 1 2 3 4

The total score is obtained by dividing the total sum of points by the number of criteria present (answered to). For example, if only 3 criteria are answered to, the total sum is divided by 3 to reveal the final score.

The Murray score ranges between 0 and 4, with scores closer to 4 indicating severe acute lung injury. Scores of 3 and above (≥2.5 if rapid deterioration) carry indication of ECMO.

The result from the Murray score can also be interpreted as follows:

■ 0 points – no lung injury;

■ 1 to 2.5 points – mild to moderate lung injury;

■ ≥5 points – severe lung injury, acute respiratory distress syndrome.


Guidelines for ECMO usage

ECMO is a technique that facilitates the transport of oxygen to the blood and is often coupled with extracorporeal carbon dioxide removal.

ECMO is becoming increasingly more prevalent in the treatment of patients with reversible lung disease presented with severe hypoxemia.

The following inclusion and exclusion criteria are based on the CESAR study which is a multicentre randomized controlled trial, aimed at highlighting the differences (treatment efficiency and costs) between conventional ventilator support and extracorporeal membrane oxygenation for severe lung failure.

Inclusion criteria – eligible patients should be:

■ Aged 18 to 65;

■ Diagnosed with potentially reversible respiratory failure;

■ Murray score of 3.0 or higher or uncompensated hypercapnia with pH <7.2.

Exclusion criteria applies for patients with:

■ High pressure (peak inspiratory pressure >30 cmH2O) or high FiO2 (>08) ventilation for more than 168 h (7 days);

■ Signs of intracranial bleeding;

■ Any other contraindication to limited heparinization.

There are some extra eligibility criteria, outside of the CESAR study:

■ Severe hypoxaemia (defined as PaO2/FiO2 <13.3 kPa);

■ Significant air leak/bronchopleural fistula;

■ Inability to achieve lung protective tidal volumes and pressures (tidal volume < 6 mL/Kg predicted body weight, plateau pressure O2);

■ Failure to improve with other therapies.


Original 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):720-3.

Other references

1. Paden ML, Conrad SA, Rycus PT, Thiagarajan RR, ELSO Registry. Extracorporeal Life Support Organization Registry Report 2012. ASAIO J. 2013; 59(3):202-10.

2. Peek GJ et al. Efficacy and economic assessment of conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multicentre randomised controlled trial. TheLancet. 2009; 374, (9698), p1351–1363.

Specialty: Pulmonology

System: Respiratory

Objective: Evaluation

Type: Score

No. Of Items: 4

Year Of Study: 1988

Article By: Denise Nedea

Published On: July 6, 2017

Last Checked: July 6, 2017

Next Review: July 6, 2023