The Murray lung injury score provides an assessment tool for evaluating the severity of lung injury based on four clinical parameters. This scoring system translates specific clinical observations into a numerical scale, which indicates the extent of lung impairment.

The calculator takes the following inputs:

1. **Alveolar consolidation on chest X-ray**  
   Ranging from no consolidation to consolidation in four quadrants:
   - None: 0 points
   - 1 quadrant: 1 point
   - 2 quadrants: 2 points
   - 3 quadrants: 3 points
   - 4 quadrants: 4 points

2. **Arterial partial pressure of oxygen/fraction of inspired oxygen (PaO2/FiO2 ratio)**  
   This assesses oxygenation status:
   - >= 300: 0 points
   - 225-299: 1 point
   - 175-224: 2 points
   - 101-174: 3 points
   - <= 100: 4 points

3. **Positive end-expiratory pressure (PEEP) in cmH2O**  
   Measures lung function support:
   - <= 5: 0 points
   - 6-8: 1 point
   - 9-11: 2 points
   - 12-14: 3 points
   - >= 15: 4 points

4. **Respiratory system compliance score in mL/cmH2O**  
   Gauges the lung’s ability to expand:
   - >= 80: 0 points
   - 60-79: 1 point
   - 40-59: 2 points
   - 20-39: 3 points
   - <= 19: 4 points

By assigning scores to each component, the responses are summed to produce a total score ranging from 0 to 16. This total is interpreted to reflect the degree of lung injury:

- A score of 0 signifies "No lung injury."
- A score between 1 and 10 is indicative of "Mild to moderate lung injury."
- A score exceeding 10 suggests "Severe lung injury."

This tool provides clinicians with a structured method to quantitatively evaluate and communicate the severity of lung injury, aiding in diagnostic and therapeutic decisions.

The Murray Lung Injury Score, also known as the Murray Score or LIS, is a clinical calculator used in the field of critical care medicine. It is specifically designed for patients with acute respiratory distress syndrome (ARDS) or acute lung injury (ALI). The Murray Score is used to quantify the severity of lung injury and helps in the decision-making process for initiating extracorporeal membrane oxygenation (ECMO) in patients with severe lung injury. It takes into account four parameters: the PaO2/FiO2 ratio, the number of quadrants on chest radiograph with alveolar consolidation, the level of positive end-expiratory pressure (PEEP), and the respiratory system compliance. 

The Murray Score is not applicable to patients without lung injury or those with chronic lung diseases. It should also be used with caution in patients with conditions that may affect the PaO2/FiO2 ratio, such as left heart failure or volume overload.