Pediatric Ards

Overview

• Definition: Pediatric Acute Respiratory Distress Syndrome (PARDS) is a life-threatening form of acute lung injury characterized by acute onset of hypoxemic respiratory failure, bilateral pulmonary infiltrates on chest imaging, and in the absence of left atrial hypertension or fluid overload. It is a diffuse inflammatory process that leads to increased pulmonary vascular permeability, lung edema, loss of aerated lung tissue, and impaired gas exchange. The diagnostic criteria for PARDS were established by the Pediatric Acute Lung Injury Consensus Conference (PALICC) in 2015.
• Epidemiology: PARDS affects approximately 2-5% of children admitted to pediatric intensive care units (PICUs) annually. Incidence varies widely by definition used and cohort studied, with reported rates ranging from 1.5 to 12.8 cases per 100,000 children per year. Mortality rates for PARDS are substantial, ranging from 15% to 30%, with higher rates observed in severe PARDS and in children with underlying comorbidities.
• Classification:
  • PALICC Criteria (2015): PARDS is classified based on oxygenation impairment, which is assessed by the oxygenation index (OI) or oxygenation saturation index (OSI) for invasively ventilated patients, and by the SpO2/FiO2 ratio for non-invasively ventilated patients.
    • Mild PARDS: Invasively ventilated: OI 4 to <8 or OSI 5 to <7.5. Non-invasively ventilated: SpO2/FiO2 ≤ 315 on ≥ 0.25 FiO2 with PEEP/CPAP ≥ 5 cm H2O.
    • Moderate PARDS: Invasively ventilated: OI 8 to <16 or OSI 7.5 to <12.3. Non-invasively ventilated: SpO2/FiO2 requirement for invasive ventilation is typically met.
    • Severe PARDS: Invasively ventilated: OI ≥ 16 or OSI ≥ 12.3. Also includes patients requiring extracorporeal membrane oxygenation (ECMO) due to refractory hypoxemia.
  • Direct vs. Indirect Lung Injury:
    • Direct (Pulmonary) Lung Injury: Primary insult directly affects the lung parenchyma (e.g., pneumonia, aspiration, drowning, pulmonary contusion).
    • Indirect (Extrapulmonary) Lung Injury: Primary insult originates outside the lung, causing systemic inflammation that secondarily affects the lung (e.g., sepsis, severe trauma, pancreatitis, major surgery, burn injury).

Pathophysiology

• Mechanism: PARDS is triggered by an initial insult (direct or indirect) that leads to a widespread inflammatory response in the lungs. This response involves:
  1. Endothelial and Epithelial Barrier Dysfunction: Pro-inflammatory mediators (cytokines, chemokines, reactive oxygen species) damage the alveolar capillary endothelium and alveolar epithelium, increasing vascular permeability.
  2. Fluid and Protein Leakage: Plasma proteins and fluid leak into the alveolar space, overwhelming lymphatic drainage, leading to pulmonary edema. This protein-rich edema fluid inactivates surfactant.
  3. Surfactant Dysfunction: Reduced production and inactivation of surfactant lead to increased alveolar surface tension, alveolar collapse (atelectasis), and decreased lung compliance.
  4. Neutrophil Influx: Neutrophils are recruited to the alveolar space, releasing proteases and oxidants that further damage lung tissue.
  5. Hyaline Membrane Formation: Denudation of alveolar epithelial cells and accumulation of cellular debris, fibrin, and plasma proteins form hyaline membranes, which further impair gas exchange.
  6. Ventilation-Perfusion Mismatch and Shunt: Alveolar collapse, fluid-filled alveoli, and compromised ventilation of perfused lung areas lead to significant ventilation-perfusion ($\dot{V}$/$\dot{Q}$) mismatch and intrapulmonary shunting, resulting in severe hypoxemia refractory to oxygen therapy.
  7. Pulmonary Hypertension: Hypoxic vasoconstriction and direct vascular injury can contribute to increased pulmonary vascular resistance and pulmonary hypertension, further complicating cardiac function.
• Risk Factors:
  • Sepsis (especially bacterial): Most common risk factor.
  • Pneumonia (viral, bacterial, fungal): Common direct lung injury.
  • Aspiration: Gastric contents, hydrocarbons.
  • Major Trauma: Including pulmonary contusion, head injury, burns.
  • Drowning/Near-drowning.
  • Transfusion-related acute lung injury (TRALI).
  • Pancreatitis.
  • Drug overdose/abuse.
  • Immunosuppression: Increased risk of severe infection.
  • Genetic predispositions: Certain genetic polymorphisms may increase susceptibility or severity.
  • Pre-existing lung disease: Asthma, cystic fibrosis, chronic lung disease of prematurity (CLD/BPD).
  • Younger age: Infants and young children may have less pulmonary reserve and increased susceptibility.
• Protective Factors:
  • Vaccination: Against common respiratory pathogens (e.g., influenza, RSV, pneumococcus) reduces the incidence of severe pneumonia.
  • Optimal management of underlying conditions: Prompt and effective treatment of sepsis, trauma, etc., can prevent progression to PARDS.
  • Nutrition: Adequate nutritional support may help maintain immune function.
  • Avoidance of iatrogenic injury: Judicious fluid management, protective ventilation strategies in at-risk patients.

Clinical Presentation

Signs and Symptoms

• Cardinal Features:
  • Acute onset of respiratory distress: Within hours to days of the inciting event.
  • Hypoxemia refractory to oxygen therapy: Worsening hypoxemia despite increasing FiO2.
  • Increased work of breathing: Tachypnea, retractions (subcostal, intercostal, supraclavicular), nasal flaring, grunting.
  • Bilateral pulmonary infiltrates on chest imaging: Not fully explained by effusions, lobar collapse, or nodules.
  • Absence of left atrial hypertension: No clinical or echocardiographic evidence of cardiogenic edema (e.g., LVEF dysfunction, elevated left atrial pressure).
• Early Signs:
  • Tachypnea and increased respiratory effort.
  • Mild hypoxemia with supplemental oxygen.
  • Irritability or lethargy (due to hypoxemia/hypercapnia).
  • Subtle changes in breath sounds (e.g., diminished, fine crackles).
• Advanced Signs:
  • Severe hypoxemia despite non-rebreather mask or high-flow nasal cannula.
  • Cyanosis (peripheral or central).
  • Signs of respiratory failure: progressively worsening work of breathing, accessory muscle use, head bobbing (in infants), gasping.
  • Altered mental status: severe lethargy, confusion, unresponsiveness.
  • Hemodynamic instability: tachycardia, hypotension, signs of shock (if associated with sepsis).
  • Decreased breath sounds, diffuse crackles, or bronchial breath sounds over consolidated areas.
• Atypical Presentations:
  • May present with initial signs mimicking bronchiolitis or asthma exacerbation in young children.
  • In patients with underlying cardiac disease, distinguishing cardiogenic pulmonary edema from PARDS can be challenging. Look for evidence of specific PARDS risk factors and absence of cardiogenic overload.
  • Subclinical PARDS may exist, manifesting only with mild hypoxemia and radiographic changes.

Physical Examination

• Inspection:
  • Respiratory rate: Often markedly elevated (tachypnea).
  • Work of breathing: Nasal flaring, retractions (subcostal, intercostal, suprasternal, supraclavicular), accessory muscle use, head bobbing, grunting.
  • Color: Pallor or cyanosis (central or peripheral) indicating hypoxemia.
  • Alertness/Consciousness: May range from agitated (early hypoxemia/hypercapnia) to lethargic or comatose (severe respiratory failure).
  • Distended neck veins: Suggestive of elevated right-sided pressures or fluid overload, but less common in pure ARDS.
  • Digital clubbing: Not an acute sign, but may suggest chronic lung disease which can predispose to ARDS.
• Palpation:
  • Tactile fremitus: May be increased over consolidated areas, decreased over areas of effusions or severe atelectasis.
  • Tracheal deviation: If pneumothorax or tension pneumothorax is present.
  • Peripheral pulses/capillary refill: Assess perfusion, especially if shock is present.
• Auscultation:
  • Breath sounds: Can be variable. Often diminished or harsh with prolong expiration. Fine crackles (rales) may be heard due to alveolar fluid. Bronchial breath sounds may indicate consolidation. Wheezing is less common but may be present in children with underlying reactive airway disease or if bronchospasm is a concomitant issue.
  • Heart sounds: Tachycardia is common. May hear gallop rhythms (S3, S4) if myocardial dysfunction is present.
  • Bowel sounds: Assess for associated abdominal pathology.
• Special Tests:
  • Pulse Oximetry: Continuous monitoring to assess oxygen saturation.
  • Capnography: If intubated, to monitor end-tidal CO2 (EtCO2) and help assess ventilation.
  • Bedside ultrasound: For rapid assessment of lung fluid, pleural effusions, cardiac function, and ruling out pneumothorax.

Diagnostic Approach

History Taking

• Key Questions:
  • Acute onset: When did respiratory symptoms start? How quickly did they progress?
  • Precipitating event: What was the initial insult? (e.g., infection, trauma, aspiration, drowning, transfusion, surgery).
  • Prior medical history:
    • Underlying cardiac disease (to rule out cardiogenic pulmonary edema).
    • Chronic lung disease (e.g., asthma, CLD/BPD, cystic fibrosis).
    • Immunosuppression or malignancy.
    • Previous PICU admissions, intubations.
  • Medications: Current medications, recent changes, drug overdose.
  • Allergies: Especially to blood products.
  • Recent travel/exposures: To infectious agents.
  • Fluid intake/urine output: To assess fluid status and renal function.
• Red Flags:
  • Rapid progression of respiratory distress.
  • Worsening hypoxemia despite increasing oxygen support.
  • Altered mental status.
  • Hemodynamic instability (hypotension, poor perfusion).
  • Recent blood transfusion (consider TRALI).
  • History of severe sepsis or septic shock.

Laboratory Tests

• First-Line:
  • Arterial Blood Gas (ABG) or Venous Blood Gas (VBG): To assess pH, PaO2/PvO2, PaCO2/PvCO2, bicarbonate, and lactate. Essential for calculating OI/OSI.
  • Complete Blood Count (CBC) with differential: Leukocytosis or leukopenia with left shift suggestive of infection; anemia may impact oxygen-carrying capacity.
  • Basic Metabolic Panel (BMP): Electrolytes, BUN, creatinine to assess renal function and fluid balance.
  • C-reactive protein (CRP) and Procalcitonin: Inflammatory markers, elevated in sepsis/severe infection.
  • Blood culture: If sepsis is suspected.
  • Respiratory viral panel: Nasal swab for common respiratory viruses (RSV, Influenza, Adenovirus, Parainfluenza, Rhinovirus, SARS-CoV-2).
• Confirmatory:
  • Echocardiogram: Crucial to rule out left ventricular dysfunction or congenital heart disease as the primary cause of pulmonary edema and to assess for pulmonary hypertension. This is key for PARDS diagnosis (absence of left atrial hypertension).
  • Bronchoalveolar lavage (BAL): If specific infection is suspected and not identified by less invasive means, or to rule out diffuse alveolar hemorrhage or other rare causes. Typically reserved for refractory cases or specific indications due to invasiveness.
• Monitoring:
  • Serial ABGs/VBGs: To monitor gas exchange and acid-base status, guide ventilator settings.
  • Daily CBC, BMP, CRP/Procalcitonin: To monitor inflammation, organ function, and identify complications.
  • Coagulation panel (PT/aPTT, fibrinogen, D-dimer): If sepsis or DIC are suspected.
  • Fluid balance: Strict intake/output monitoring, daily weights.

Imaging

• Recommended:
  • Chest Radiograph (CXR): Bilateral patchy or diffuse alveolar/interstitial infiltrates, usually non-lobar, that are not fully explained by effusions, atelectasis, or nodules. May evolve from initially clear to diffuse infiltrates over hours. Crucial for diagnosis.
• Advanced:
  • Chest Computed Tomography (CT): Not routinely indicated for initial diagnosis in PARDS due to radiation exposure and need for transport, but can be helpful in specific situations:
    • To rule out other pathologies (e.g., pulmonary embolism in selected cases, diffuse parenchymal lung disease, abscess).
    • To assess lung morphology for potential therapies (e.g., recruitment maneuvers).
    • If CXR findings are atypical or unclear.
  • Lung Ultrasound: Increasingly used at the bedside to assess for pulmonary edema (B-lines), pleural effusions, consolidation, and pneumothorax, guiding fluid management and rapid identification of complications. It is non-invasive and avoids radiation.

Management

Acute Management (Goal: Optimize oxygenation and ventilation, minimize ventilator-induced lung injury)

• Immediate:
  • Secure airway: Endotracheal intubation and mechanical ventilation are often required for moderate to severe PARDS.
  • Optimize oxygenation: Start with FiO2 1.0, then titrate down.
  • Circulatory support: Intravenous fluid resuscitation for shock, cautious fluid management. Vasopressors (e.g., norepinephrine, epinephrine) if fluid refractory shock.
• Stabilization:
  • Lung-protective ventilation strategy:
    • Low tidal volumes (V_T): Aim for 4-8 mL/kg of predicted body weight (PBW) to prevent volutrauma. Start at 6 mL/kg PBW.
    • Maintain plateau pressure (P_plat): Keep P_plat < 28 cm H2O (or < 29 cm H2O in older children, < 26 cm H2O in neonates) to prevent barotrauma.
    • Positive End-Expiratory Pressure (PEEP): Use sufficient PEEP (often 8-15 cm H2O or higher) to prevent alveolar collapse (atelectrauma) and recruit alveoli. Titrate PEEP to optimize oxygenation and compliance while minimizing hemodynamic compromise.
    • Permissive hypercapnia: Allow PaCO2 to rise (typically up to 60-65 mmHg, pH > 7.20-7.25) to facilitate low V_T ventilation, unless signs of intracranial hypertension or severe pulmonary hypertension.
    • Respiratory rate: Adjust to achieve target PaCO2.
  • Fluid management:
    • Conservative fluid strategy: After initial resuscitation, aim for a negative or even fluid balance to minimize pulmonary edema. Frequent assessment of fluid responsiveness and judicious use of diuretics. Daily weights are critical.
  • Sedation and analgesia: Judicious use of sedatives (e.g., fentanyl, midazolam, dexmedetomidine) to reduce patient-ventilator asynchrony, decrease oxygen consumption, and prevent self-extubation. Neuromuscular blockade may be considered in severe cases with persistent asynchrony or high ventilator pressures, but use sparingly due to risks (e.g., prolonged weakness, critical illness polyneuromyopathy).
  • Treat underlying cause: Initiate broad-spectrum antibiotics promptly if infection is suspected. Start antiviral or antifungal therapy if indicated. Address other inciting factors (e.g., trauma, aspiration).
  • Nutrition: Initiate early enteral nutrition if feasible (trophic feeds initially) to preserve gut integrity.
• Emergency:
  • Refractory hypoxemia/hypercapnia: Despite protective ventilation, consider:
    • Prone positioning: Improves $\dot{V}$/$\dot{Q}$ matching, recruits dorsal lung regions. Should be considered early for severe PARDS.
    • Inhaled nitric oxide (iNO): Selective pulmonary vasodilator, may improve oxygenation in some PARDS patients with pulmonary hypertension, but no consistent mortality benefit. Consider for severe hypoxemia with evidence of pulmonary hypertension.
    • High-frequency oscillatory ventilation (HFOV): Provides small tidal volumes at very high frequencies, potentially reducing VILI. No clear mortality benefit over conventional ventilation in many studies, but can be a rescue therapy.
    • Extracorporeal Membrane Oxygenation (ECMO): Considered for life-threatening hypoxemia or hypercapnia refractory to all conventional and rescue therapies. Requires specialized expertise and resources. Eligibility criteria typically involve severe oxygenation failure (e.g., OI > 30-40 despite optimal ventilation) or inability to maintain adequate CO2 removal.
  • Pneumothorax/Tension Pneumothorax: Urgent needle decompression and chest tube insertion.

Chronic Management (Focus on weaning from ventilation, rehabilitation, and long-term sequelae)

• Pharmacological:
  • Diuretics: After initial resuscitation, to achieve negative fluid balance and reduce pulmonary edema.
  • Corticosteroids: Generally not recommended for routine use in PARDS. May be considered in specific inflammatory conditions (e.g., severe asthma exacerbation precipitating PARDS, acute eosinophilic pneumonia) or in late-phase ARDS for persistent inflammation, but evidence in pediatric PARDS is limited and controversial.
  • Pulmonary vasodilators (e.g., sildenafil): Only if significant pulmonary hypertension is a persistent issue and affecting right ventricular function.
  • Anti-fibrotic agents: Not routinely used in PARDS.
• Non-pharmacological:
  • Weaning from mechanical ventilation: Gradual reduction of ventilatory support as lung function improves. Spontaneous breathing trials (SBTs) to assess readiness for extubation.
  • Mobilization and rehabilitation: Early mobilization, physical therapy, and occupational therapy to prevent critical illness myopathy/neuropathy and promote functional recovery.
  • Nutritional support: Adequate calories and protein crucial for recovery.
  • Psychosocial support: For patients and families addressing anxiety, depression, and PTSD associated with prolonged critical illness.
• Monitoring:
  • Long-term pulmonary function tests (PFTs): To assess for residual lung impairment (restrictive and/or obstructive PFTs) post-discharge.
  • Neurocognitive and developmental assessments: To identify long-term neurocognitive deficits, especially in infants and young children.
  • Mental health screening: For anxiety, depression, and PTSD in survivors and their families.
  • Regular follow-up with pulmonology, critical care, and rehabilitation specialists.

Treatment Algorithms

• First-Line:
  1. Diagnosis of PARDS: Based on PALICC criteria.
  2. Identify and treat underlying cause.
  3. Lung-protective mechanical ventilation:
     • V_T 4-8 mL/kg PBW, P_plat < 28 (or age-appropriate limits).
     • Optimize PEEP to maintain open lung and oxygenation.
     • Permissive hypercapnia (pH > 7.20-7.25).
  4. Conservative fluid management: After initial resuscitation.
  5. Sedation and analgesia.
  6. Nutritional support.
• Second-Line (for refractory hypoxemia/hypercapnia despite first-line):
  1. Prone positioning: Implement early for severe PARDS.
  2. Consider HFOV: If available and expertise present.
  3. Consider iNO: Especially with evidence of pulmonary hypertension.
  4. Consider neuromuscular blockade: For severe patient-ventilator asynchrony despite optimal sedation.
• Refractory Cases (Life-threatening hypoxia/hypercapnia despite all above):
  1. ECMO (VV-ECMO is preferred for primary lung support): Bridge to recovery, considered center-dependent and based on specific criteria (e.g., OI > 30-40 for several hours, uncorrectable acidosis).

Complications

• Common:
  • Ventilator-associated pneumonia (VAP).
  • Barotrauma/Volutrauma: Pneumothorax, pneumomediastinum, subcutaneous emphysema.
  • Central line-associated bloodstream infections (CLABSI).
  • Catheter-associated urinary tract infections (CAUTI).
  • Delirium in PICU.
  • Electrolyte imbalances, renal dysfunction.
• Serious:
  • Multisystem organ failure: Kidney injury, liver dysfunction, circulatory shock.
  • Severe pulmonary hypertension and right ventricular failure.
  • Thromboembolic events: DVT, PE (especially in immobilized patients).
  • Intracranial hemorrhage: Particularly in neonates/young infants on ECMO.
• Long-term:
  • Chronic lung disease: Reduced lung function (restrictive, obstructive patterns), persistent gas exchange abnormalities.
  • Neurocognitive impairment: Learning difficulties, memory impairments, attention deficits.
  • Post-intensive care syndrome (PICS): Physical weakness, fatigue, psychiatric problems (anxiety, depression, PTSD) in both survivors and their caregivers.
  • Growth failure/Sarcopenia.

Prognosis

• Factors:
  • Severity of PARDS: Higher mortality with moderate and severe PARDS (PALICC classification).
  • Underlying etiology: Sepsis is associated with higher mortality.
  • Presence of comorbidities: Malignancy, immunodeficiency, chronic lung disease, heart disease increase mortality.
  • Development of multisystem organ failure: A strong predictor of poor outcome.
  • Oxygenation index (OI) or Oxygenation Saturation Index (OSI): Higher values correlate with increased mortality.
  • Initial response to protective ventilation and rescue therapies.
• Survival:
  • Overall mortality for PARDS ranges from 15-30%.
  • Mild PARDS: <10% mortality.
  • Moderate PARDS: 15-20% mortality.
  • Severe PARDS: 25-40% mortality (can be higher for specific etiologies or in presence of multi-organ failure).
  • Mortality rates may be lower in centers with experienced PARDS teams and readily available rescue therapies (e.g., ECMO).
• Quality of Life:
  • Many survivors experience long-term physical, neurocognitive, and psychological impairments.
  • Reduced exercise tolerance and persistent respiratory symptoms are common (e.g., cough, wheezing).
  • Up to 50% of survivors may have some degree of neurocognitive impairment at 1-2 years post-discharge.
  • Psychological sequelae (anxiety, depression, PTSD) affect patients and families, impacting overall quality of life.

Prevention

• Primary:
  • Vaccination: Routine childhood immunizations (e.g., DTaP, Hib, PCV13, influenza, RSV monoclonal antibody for eligible infants) to prevent severe infections that can lead to PARDS.
  • Infection control: Hand hygiene, isolation precautions in healthcare settings.
  • Early recognition and optimal management of sepsis: Prompt diagnosis and initiation of guideline-directed therapy.
  • Aspiration precautions: For patients at risk (e.g., those with neurological impairment, feeding difficulties).
  • Safe transfusion practices: Minimizing unnecessary transfusions, adherence to TRALI prevention strategies.
• Secondary:
  • Early recognition of developing PARDS: Close monitoring of at-risk patients for signs of hypoxemia, increased work of breathing, and radiographic changes.
  • Prompt initiation of lung-protective ventilation: In patients requiring mechanical ventilation, even before full PARDS criteria are met, if risk factors are high.
  • Judicious fluid management: Avoid over-resuscitation in patients with shock, especially after initial stabilization.
• Tertiary:
  • Minimizing ventilator-induced lung injury (VILI): Strict adherence to lung-protective ventilation.
  • Early mobilization and rehabilitation: To prevent deconditioning and improve long-term functional status.
  • Aggressive management of complications: Prompt treatment of VAP, pneumothorax, nutritional deficiencies.
  • Post-PICU follow-up: To address long-term physical, psychological, and neurocognitive needs.

Special Populations

• Neonatal/Infants:
  • Physiological differences: Smaller airways, higher chest wall compliance, higher metabolic rate.
  • Smaller tidal volumes: PBW estimation is crucial.
  • Higher baseline respiratory rates: Requires careful adjustment of ventilator settings.
  • Increased susceptibility to atelectasis: Higher PEEP may be needed.
  • Greater risk of neurodevelopmental impairment: Post-PARDS, long-term follow-up is critical.
  • Consider MAS (Meconium Aspiration Syndrome) as a direct pulmonary injury.
• Immunocompromised Children:
  • Higher risk of severe and atypical infections (e.g., fungal, PJP, CMV).
  • Increased mortality.
  • Consider specific anti-infective therapies early.
  • Corticosteroids may be indicated for underlying inflammatory conditions or as part of specific infection treatments (e.g., PJP).
• Children with Chronic Lung Disease (e.g., CLD/BPD, Cystic Fibrosis, severe asthma):
  • Baseline altered lung mechanics and gas exchange.
  • Diagnosis of PARDS can be more challenging as some features may overlap with their baseline condition.
  • Increased risk of PARDS and worse outcomes.
  • Ventilation strategies may need modification based on baseline lung pathology (e.g., may tolerate higher P_plat in some obstructive diseases).
• Children with Underlying Cardiac Disease:
  • Differentiation from cardiogenic pulmonary edema is paramount. Echocardiography is essential.
  • Aggressive fluid restriction in PARDS may be poorly tolerated if there's significant right heart dysfunction or fixed cardiac output.
  • Careful balance between fluid management and cardiac output.

Clinical Pearls

• Diagnostic:
  • Don't forget the echocardiogram: Essential to rule out left atrial hypertension or cardiac dysfunction as the primary cause of pulmonary edema.
  • PALICC criteria: Apply them rigorously for consistent diagnosis and prognostication. The SpO2/FiO2 ratio with PEEP/CPAP ≥ 5 cm H2O is a reliable non-invasive way to categorize PARDS severity.
  • Bilateral infiltrates: On CXR, ensure they are not solely due to effusions or lobar collapse.
  • Timing is everything: Acute onset within 7 days of known clinical insult.
• Treatment:
  • Lung protective ventilation is paramount: Low V_T (4-8 mL/kg PBW) and P_plat limits (<28 cm H2O) are non-negotiable.
  • PEEP titration: It's individualized; adequate PEEP prevents atelectrauma and improves oxygenation, but excessive PEEP can impair hemodynamics.
  • Prone early for severe PARDS: It's a low-cost, effective maneuver if tolerated.
  • Conservative fluids after resuscitation: Avoid positive fluid balance once shock is resolved.
  • Manage patient-ventilator asynchrony effectively: Optimize sedation; consider neuromuscular blockers judiciously for severe cases.
  • Early tracheostomy: Consider for anticipated prolonged ventilation (>2-3 weeks) to facilitate weaning, reduce sedation, and improve mobility.
• Pitfalls:
  • Incorrect calculation of V_T: Using actual body weight instead of predicted body weight can lead to excessive V_T in obese children.
  • Aggressive fluid administration: Can worsen pulmonary edema and prolong illness.
  • Delay in treating the underlying cause: Leads to ongoing inflammation and worsening PARDS.
  • Over-reliance on pressure-controlled ventilation without monitoring P_plat: Patients may be receiving excessive tidal volumes which can cause VILI.
  • Prolonged neuromuscular blockade: Increases risk of critical illness myopathy/neuropathy.
  • Lack of attention to nutritional support: Worsens outcomes.
  • Forgetting about non-pulmonary organ support: Kidney, liver, cardiac dysfunction secondary to sepsis or PARDS can dictate overall outcome.

Recent Updates

• Guidelines:
  • PALICC 2 (2023) - Pediatric Acute Lung Injury Consensus Conference: Anticipated to refine existing definitions, potentially incorporate novel biomarkers, and provide updated evidence-based recommendations for management of PARDS.
  • Surviving Sepsis Campaign Guidelines for Children (2020): Emphasize early recognition and management of sepsis as a leading cause of PARDS, including fluid resuscitation, antimicrobial therapy, and vasopressors for shock.
• Evidence:
  • Increasing evidence for lung-protective ventilation in PARDS: Consistent findings reinforcing the importance of low tidal volume and plateau pressure limitation.
  • Prone positioning: Continued studies support the early and routine use of prone positioning in severe PARDS, showing improved oxygenation and potentially reduced duration of ventilation/mortality.
  • Conservative fluid management: Meta-analyses continue to support conservative fluid strategies post-resuscitation for improved outcomes.
  • Neurodevelopmental outcomes: Growing body of literature highlighting the long-term neurocognitive and psychological sequelae of PARDS, emphasizing the need for comprehensive follow-up programs.
  • Role of ECMO: Continued refinement of patient selection criteria and management protocols in pediatric ECMO centers, leading to improved survival for very severe, refractory PARDS.
• Controversies:
  • Optimal PEEP titration strategy: There is no universally agreed-upon method, with various approaches (e.g., PEEP/FiO2 tables, stress-index guided, esophageal pressure) in use, each with pros and cons.
  • Role of corticosteroids: Still debated, lacking strong evidence for routine use in undifferentiated PARDS. May be beneficial in specific subgroups or phases.
  • Ventilator modes: No single ventilator mode (pressure-controlled, volume-controlled, HFOV) has consistently demonstrated superiority in pediatric ARDS. Selection often depends on clinician preference, local expertise, and patient response.
  • Biomarkers for diagnosis and prognosis: Research continues into novel biomarkers (e.g., plasma, BAL-derived) and genetic predispositions that could facilitate earlier diagnosis, prognostication, and more targeted therapies.

Key References

• Guidelines:
  • Pediatric Acute Lung Injury Consensus Conference (PALICC) Criteria (2015): ARDS Definition Task Force. Pediatric acute respiratory distress syndrome: consensus recommendations from the Pediatric Acute Lung Injury Consensus Conference. Pediatr Crit Care Med. 2015;16(2):109-119.
  • Surviving Sepsis Campaign International Guidelines for the Management of Septic Shock and Sepsis-Associated Organ Dysfunction in Children (2020): Weiss SL, et al. Pediatr Crit Care Med. 2020;21(2):e52-e106.
• Studies:
  • ARDSNet (Adult Study): The Acute Respiratory Distress Syndrome Network. Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. N Engl J Med. 2000;342(18):1301-1308. (Foundational for protective ventilation, extrapolated to pediatrics).
  • PRACTICAL Study (Pediatric ARDS in resource limited settings): Multiple papers evaluating epidemiology and outcomes.
  • PROSEVA Trial (Adult Study): Guérin C, et al. Prone positioning in severe acute respiratory distress syndrome. N Engl J Med. 2013;368(23):2159-2168. (Landmark study on prone positioning, influencing pediatric practice).
• Reviews:
  • Cholette JM, et al. Pediatric ARDS. In: Fuhrman BP, Zimmerman JJ, eds. Pediatric Critical Care. 5th ed. Elsevier; 2017:423-437. (Comprehensive textbook chapter)
  • PIVA (Pediatric Sepsis and ARDS) Network publications and reviews on specific interventions.

Medical Disclaimer

This information is for clinical reference and educational purposes only and should not be considered medical advice. It is intended to supplement, not replace, the knowledge, experience, and judgment of qualified healthcare professionals. Patient care decisions must always be made based on the individual patient's clinical presentation, medical history, local clinical guidelines, and available resources. Dosages, criteria, and recommendations are subject to change and should be verified with official prescribing information and current clinical guidelines. The authors and publishers disclaim any liability or responsibility for any injury or damage to persons or property resulting from any use of or reliance on this material.