## How is Murray score calculated?

The Murray scoring system includes 4 criteria for the development of ALI/ARDS: a “scoring” of hypoxemia, a “scoring” of respiratory system compliance, chest radiographic findings, and level of positive end-expiratory pressure. Each criterion receives a score from 0 to 4 according to the severity of the condition.

## What is the AOI score?

The AOI or Age-Adjusted Oxygenation Index is another score used to grade the severity and prognosis of ARDS [6]. The AOI is calculated by measuring the mean airway pressure and multiplying it with the FiO2, afterwards the value is divided by the PaO2 [6]. The APSS scoring system was created in 2016.

**How is acute lung injury calculated?**

ARDS causes diffuse lung inflammation which leads to increased pulmonary vascular permeability, pulmonary edema, and alveolar epithelial injury….Calculating Acute Respiratory Distress Syndrome (ARDS) Severity.

Berlin Definition of ARDS (Ranieri et al., 2012) | |
---|---|

ARDS Severity | PaO2/FiO2 |

Moderate | 100 – 199 |

Severe | < 100 |

*on positive end expiratory pressure (PEEP) ≥ 5 cm H2O |

**What is the difference between ALI and ARDS?**

Acute respiratory distress syndrome (ARDS), and its milder form acute lung injury (ALI), are a spectrum of lung diseases characterised by a severe inflammatory process causing diffuse alveolar damage and resulting in a variable degree of ventilation perfusion mismatch, severe hypoxaemia, and poor lung compliance.

### What is PF ratio in ARDS?

The current Definition of ARDS for Oxygenation is P/F Ratio of 300 to 200 is Mild, 200 to 100 is Moderate and less than 100 is Severe ARDS with PEEP ≥ 5.

### What is Peep measured in?

This pressure is measured in centimeters of water. PEEP therapy can be effective when used in patients with a diffuse lung disease that results in an acute decrease in functional residual capacity (FRC), which is the volume of gas that remains in the lung at the end of a normal expiration.

**What is the Silverman score?**

The Silverman-Andersen Retraction Score (SAs) is used to assess severity of respiratory distress in newborn and preterm infants without respiratory support. The score comprises 4 inspiratory categories of movements (thoraco-abdominal, intercostal, xiphoid, and chin movements) and one expiratory category (grunting).

**What is PaO2 FiO2 ratio?**

PaO2/FiO2 ratio is the ratio of arterial oxygen partial pressure (PaO2 in mmHg) to fractional inspired oxygen (FiO2 expressed as a fraction, not a percentage) also known as the Horowitz index, the Carrico index, and (most conveniently) the P/F ratio.

## How is SF ratio calculated?

SF values were examined as a substitute of PF ratio for diagnosis ARDS and ALI. Results: The relationship between SF and PF ratio was described by the following regression equation: SF=57+0.61 PF (P<0.001). SF ratios of 181 and 235 corresponded of PF ratio 300 and 200.

## How do you calculate pao2 fio2 ratio?

P divided by F = P/F ratio. Example: PaO2 = 90 on 40% oxygen (FIO2 = 0.40): 90 / 0.40 = P/F ratio = 225. A P/F ratio of 225 is equivalent to a pO2 of 45 mmHg, which is significantly < 60 mmHg on room air.

**How do you calculate ARDS ratio?**

The P/F ratio equals the arterial pO2 (“P”) from the ABG divided by the FIO2 (“F”) – the fraction (percent) of inspired oxygen that the patient is receiving expressed as a decimal (40% oxygen = FIO2 of 0.40). A P/F Ratio less than 300 indicates acute respiratory failure.

**What is a normal P F ratio?**

A normal P/F Ratio is ≥ 400 and equivalent to a PaO2 ≥ 80 mmHg on room air.