PF Ratio Formula:
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Definition: The PF ratio (PaO₂/FiO₂ ratio) is a measure of oxygenation used to assess the severity of respiratory failure, including pediatric ARDS.
Purpose: It helps clinicians evaluate lung function and determine appropriate treatment strategies for children with respiratory distress.
The calculator uses the formula:
Where:
Explanation: The ratio compares the oxygen level in arterial blood to the amount of oxygen being delivered to the patient.
Normal: >300 mmHg
Mild ARDS: 200-300 mmHg
Moderate ARDS: 100-200 mmHg
Severe ARDS: <100 mmHg
Tips: Enter the PaO₂ value from arterial blood gas (in mmHg) and the FiO₂ (0.21 for room air to 1.0 for 100% oxygen).
Q1: Why is PF ratio important in pediatrics?
A: It helps assess oxygenation status independent of ventilator settings, crucial for managing pediatric respiratory failure.
Q2: How does pediatric ARDS differ from adult ARDS?
A: Children may have different thresholds and progression patterns, making specific pediatric assessment important.
Q3: When should I use this calculator?
A: For any pediatric patient with respiratory distress, especially when considering ARDS diagnosis or ventilator management.
Q4: What are limitations of PF ratio?
A: It doesn't account for PEEP or mean airway pressure, which may be important in ventilated patients.
Q5: How often should PF ratio be calculated?
A: With each arterial blood gas analysis in patients with respiratory compromise or when oxygen requirements change.