Pediatric Acute Respiratory Distress Syndrome (PARDS) is staged using the Oxygenation Index (OI) for invasive ventilation and Oxygen Saturation Index (OSI) when arterial lines are absent.
Key Physiological Equations & Formulas
Oxygenation Index (OI):
$$OI = \frac{MAP \times FiO_2 \times 100}{PaO_2}$$Mild: 4 <= OI < 8. Moderate: 8 <= OI < 16. Severe: OI >= 16.
Oxygen Saturation Index (OSI):
$$OSI = \frac{MAP \times FiO_2 \times 100}{SpO_2}$$Mild: 5 <= OSI < 7.5. Moderate: 7.5 <= OSI < 12.3. Severe: OSI >= 12.3 (for SpO2 88-97%).
Practical Clinical Pearls & Bedside Rules
- PALICC-2 Lung Protective Rules: Target Vt 4-6 mL/kg in poorly compliant lungs; maintain driving pressure Delta P < 15 cmH2O; plateau pressure Pplat <= 28 cmH2O (or <= 32 if chest wall elastance is high).
- Permissive Hypercapnia: Target arterial pH 7.20-7.30 (pH > 7.15 in severe PARDS) provided intracranial pressure and pulmonary hypertension are absent.
Initial Settings & Clinical Titration Protocol
| Parameter | Recommended Initial Setting | Titration Goal / Safety Threshold |
|---|---|---|
| Mode Selection | PC-CMV or PRVC | Ensure tight peak pressure limits while monitoring delivered volume. |
| PEEP Titration | 8-14 cmH2O in moderate/severe PARDS | Titrate using PALICC-2 PEEP/FiO2 matrix. |
Bedside Troubleshooting & Red Flags
Warning
Refractory Hypoxemia (OI >= 16): Initiate early neuromuscular blockade (<=48h), prone positioning (16-24h/day), and evaluate for VV-ECMO.
Key Takeaways & Summary
- Always evaluate patient synchrony and physiological response before changing ventilator parameters.
- Maintain lung-protective strategies to minimize driving pressure ($\Delta P$) and mechanical power.
- Continuously reassess liberation and extubation readiness on daily morning rounds.