What is the initial management of Acute Respiratory Distress Syndrome (ARDS) in pediatric patients?

Initial Management of Pediatric Acute Respiratory Distress Syndrome (PARDS)

Immediately implement lung-protective mechanical ventilation with tidal volumes of 4-8 mL/kg predicted body weight (not actual body weight) and maintain plateau pressures ≤30 cmH₂O as the cornerstone of PARDS management. 1, 2

Immediate Assessment and Respiratory Support Decision

Consider Non-Invasive Ventilation First (Selected Patients Only)

• A trial of non-invasive ventilation (NIV) or high-flow nasal cannula may be attempted only in children without clear intubation indications who are responding to initial resuscitation. 1, 2
• Reassess the patient's condition carefully and frequently within 1 hour of NIV initiation—do not delay intubation if deterioration occurs, as this is associated with worse outcomes. 2, 3
• Contraindications to NIV include impaired consciousness, inability to protect airway, hemodynamic instability, copious secretions, or multi-organ failure. 3

Proceed to Intubation for Most Patients

• Most children with PARDS require intubation in a controlled setting rather than emergent intubation. 3
• Avoid etomidate when intubating children with septic shock or sepsis-associated organ dysfunction. 1

Lung-Protective Mechanical Ventilation Parameters

Tidal Volume

• Set tidal volume at 4-8 mL/kg predicted body weight—never use actual body weight for calculations. 1, 2
• This is the only strategy that has consistently improved outcomes in ARDS. 4
• Studies show that over 25% of pediatric ARDS patients are still ventilated with tidal volumes above 10 mL/kg in actual practice, which must be avoided. 5

Plateau Pressure

• Limit plateau pressure to ≤28-30 cmH₂O in most cases. 1, 2
• In restrictive lung disease with increased chest wall elastance, plateau pressures up to 29-32 cmH₂O may be acceptable. 1
• Plateau pressures should be checked regularly and never exceed 30 cmH₂O. 1, 2

Positive End-Expiratory Pressure (PEEP)

• Use higher PEEP in moderate-to-severe PARDS, guided by the ARDS-network PEEP-to-FiO₂ grid. 1, 2, 3
• Start with PEEP ≥12 cmH₂O in severe cases. 1
• The exact level of high PEEP has not been definitively determined in PARDS patients, but avoid limiting PEEP to ~10 cmH₂O as oxygenation worsens—this is a common pitfall. 6
• Be aware that adverse hemodynamic effects of high PEEP may be more prominent in children with septic shock. 1

Inspiratory Time and Respiratory Rate

• Set inspiratory time and respiratory rate based on respiratory system mechanics and disease trajectory—these parameters are closely correlated. 1
• In restrictive lung disease, use a higher respiratory rate to compensate for low tidal volume and maintain minute ventilation. 1
• Avoid flow end-inspiratory or expiratory flow interruption to prevent air-trapping. 1

Oxygenation and Ventilation Targets

Oxygenation Goals

• Target SpO₂ 92-96% to avoid oxygen toxicity—do not target higher saturations. 2, 3
• Target PaO₂ 70-90 mmHg. 2
• Permissive mild hypoxemia (SpO₂ as low as 88%) is tolerable in many cases. 5

Ventilation Goals

• Accept permissive hypercapnia with pH as low as 7.20 for ≥6 hours if necessary to maintain lung-protective ventilation. 1
• Many pediatric intensivists consider permissive hypercapnia tolerable. 5

Sedation and Spontaneous Breathing

Sedation Strategy

• Sedation should be titrated according to local protocols, including regular drug interruption. 1
• As oxygenation improves and FiO₂/PEEP can be reduced, stop or reduce sedation and assess for weaning readiness. 1

Spontaneous Breathing

• All children on respiratory support should preferably breathe spontaneously, except the most severely ill children requiring very high ventilator settings. 1
• In severely ill children with restrictive, obstructive, or mixed disease requiring very high settings, use controlled mechanical ventilation with continuous sedation and/or muscle relaxants. 1
• Partial ventilatory support requires less sedation and can reduce ventilation-perfusion mismatch, but patient-ventilator synchrony is paramount. 1

Adjunctive Therapies for Severe PARDS

Prone Positioning

• Implement prone positioning for at least 12 hours per day in children with severe PARDS (PaO₂/FiO₂ <100 mmHg). 1, 2, 7
• This intervention has demonstrated significant mortality reduction in severe ARDS. 3
• Apply deep sedation and analgesia during prone positioning. 3

Neuromuscular Blockade

• Consider neuromuscular blockade for 24-48 hours after ARDS onset in severe PARDS to improve ventilator synchrony and reduce oxygen consumption. 1, 2, 7
• Cisatracurium infusion for 48 hours in early severe ARDS is particularly beneficial when ventilator-patient dyssynchrony persists despite sedation. 3
• Caution is advised when using sedation and relaxation in the presence of cardiac dysfunction. 1

Recruitment Maneuvers

• No definitive recommendation can be made for or against recruitment maneuvers in children with PARDS and refractory hypoxemia. 1
• If a recruitment maneuver is considered, use a stepwise, incremental and decremental PEEP titration maneuver rather than sustained inflation techniques. 1
• All PARDS patients must be carefully monitored for tolerance of the maneuver. 1

Inhaled Nitric Oxide (iNO)

• Do not routinely use iNO in all children with sepsis-induced PARDS. 1, 7
• Consider iNO as rescue therapy only in children with PARDS and refractory hypoxemia after other oxygenation strategies have been optimized. 1, 7
• Discontinue if no rapid improvement in oxygenation occurs. 3

High-Frequency Oscillatory Ventilation (HFOV)

• Do not routinely use HFOV in patients with moderate or severe ARDS. 1
• HFOV may be considered if conventional ventilation fails, using an open lung strategy to maintain optimal lung volume. 1
• A mortality benefit of HFOV in acute hypoxemic respiratory failure has not been shown. 1
• HFOV should not be used in obstructive airway disease because of the risk of dynamic hyperinflation. 1

Fluid Management

• Implement conservative fluid management once respiratory status is stabilized to minimize pulmonary edema while maintaining adequate organ perfusion. 2, 7, 3
• Monitor fluid balance carefully—excessive fluid administration worsens oxygenation, promotes right ventricular failure, and increases mortality. 3
• Accurate recording of fluid intake and output is important. 1

Monitoring Requirements

Continuous Monitoring

• Continuously monitor oxygen saturation, respiratory mechanics, and hemodynamics to promptly identify deterioration. 2, 3
• Monitor for ventilator-patient dyssynchrony. 3

Echocardiography

• Assess right ventricular function via echocardiography, as RV failure significantly worsens outcomes. 2, 3
• Repeated echocardiography is essential during management. 1

Blood Gas Monitoring

• Arterial blood gas analysis should be performed at 1-2 hours and again at 4-6 hours if initial improvement is minimal. 3

Advanced Rescue Therapies

Extracorporeal Membrane Oxygenation (ECMO)

• Consider venovenous ECMO (VV-ECMO) only at centers with ECMO expertise for patients with severe ARDS failing conventional management, particularly those with potentially reversible disease. 1, 2, 3
• VV-ECMO is indicated in patients with severe ARDS within 7 days after onset with persistent life-threatening hypoxemia (PaO₂/FiO₂ <70 for ≥3 hours or <100 for ≥6 hours) unresponsive to optimized supportive therapy. 1
• If no ECMO is available, early consultation of an ECMO center is recommended because transporting patients who need ECMO can be hazardous. 1
• All ECMO techniques carry hemodynamic risks and require expertise, experience, and an interdisciplinary approach. 1

Common Pitfalls to Avoid

• Never use actual body weight for tidal volume calculations—always use predicted body weight. 2, 3
• Do not limit PEEP to ~10 cmH₂O as oxygenation worsens—this is inadequate in moderate-to-severe PARDS. 6
• Do not delay intubation in patients failing NIV—this is associated with worse outcomes. 2, 3
• Do not target SpO₂ higher than 96%—this increases oxygen toxicity risk. 3
• Do not tolerate plateau pressures above 30 cmH₂O. 1, 2