Overview
Definition:
Pediatric Acute Respiratory Distress Syndrome (PARDS) is a severe, acute lung injury characterized by non-cardiogenic pulmonary edema, hypoxemia, and bilateral opacities on chest imaging, leading to respiratory failure
it is distinct from adult ARDS due to differences in etiology, pathophysiology, and response to therapy.
Epidemiology:
Incidence in children varies widely, estimated between 1.5 to 6 per 100,000 person-years, with higher rates in critically ill populations
mortality remains significant, around 20-40%, depending on severity, underlying cause, and availability of advanced care.
Clinical Significance:
PARDS is a leading cause of respiratory failure and mortality in pediatric intensive care units
understanding its management, including current guidelines like PALICC and adjunctive therapies such as proning, is crucial for improving patient outcomes and is a frequently tested topic in postgraduate medical examinations like DNB and NEET SS.
Clinical Presentation
Symptoms:
Rapid onset of dyspnea
Tachypnea
Grunting respirations
Nasal flaring and retractions
Cyanosis despite supplemental oxygen
Decreased level of consciousness.
Signs:
Diffuse crackles on auscultation
Increased work of breathing
Tachycardia
Hypotension (in later stages or with sepsis)
Increased oxygen requirements
Diffuse bilateral infiltrates on chest X-ray or CT.
Diagnostic Criteria:
The Berlin definition for ARDS, adapted for pediatrics (PALICC definition), requires acute onset, bilateral opacities on imaging not fully explained by effusions, lobar/lung collapse, or nodules, and respiratory failure not fully explained by cardiac dysfunction or fluid overload
severity is graded by PaO2/FiO2 ratio.
Diagnostic Approach
History Taking:
Focus on potential triggers: recent infection (viral, bacterial, fungal), aspiration, trauma, sepsis, pancreatitis, drowning, or underlying conditions like congenital heart disease or immunodeficiency
Document chronicity of respiratory symptoms
Inquire about recent illnesses or travel.
Physical Examination:
Assess respiratory rate, pattern, and effort
Examine for accessory muscle use, retractions, and nasal flaring
Auscultate lung fields for crackles, wheezes, or diminished breath sounds
Evaluate for peripheral edema, cyanosis, and level of consciousness.
Investigations:
Chest X-ray or CT scan showing bilateral opacities
Arterial blood gas (ABG) analysis to assess oxygenation and ventilation (hypoxemia, normal or low PaCO2)
Complete blood count (CBC) to detect infection or inflammation
Inflammatory markers (CRP, procalcitonin)
Sepsis workup (blood cultures, urine culture, CSF analysis)
Coagulation profile
Cardiac evaluation (ECG, echocardiogram) to rule out cardiac causes
Viral respiratory panel
Other specific investigations based on suspected etiology.
Differential Diagnosis:
Congenital heart disease with pulmonary edema
Bronchopulmonary dysplasia
Acute asthma exacerbation
Pneumonia (non-ARDS related)
Pulmonary hemorrhage
Pulmonary embolism
Drowning
Systemic inflammatory response syndrome (SIRS) without ARDS.
Management
Initial Management:
Secure airway and initiate mechanical ventilation
Optimize oxygenation and ventilation
Administer fluids judiciously
Provide sedation and analgesia
Treat underlying cause (e.g., antibiotics for bacterial pneumonia, antivirals for influenza).
Mechanical Ventilation Palicc:
Lung-protective ventilation strategies are paramount: Low tidal volume (4-6 mL/kg predicted body weight)
Permissive hypercapnia (pH > 7.20)
Appropriate PEEP (titrated to lung recruitment, often higher than adult ARDS)
Minimize ventilator-induced lung injury (VILI)
Consider high-frequency oscillatory ventilation (HFOV) for severe hypoxemia refractory to conventional ventilation
Monitor plateau pressure (<30 cmH2O).
Adjunctive Therapies:
Prone positioning: Consider for moderate to severe PARDS (PaO2/FiO2 < 150) for at least 12-16 hours daily
Neuromuscular blockade: May be considered in severe ARDS for ventilator synchrony, but with caution due to potential complications
Surfactant therapy: Role is controversial and not routinely recommended in all PARDS cases
may be considered in specific etiologies like meconium aspiration
Corticosteroids: Not routinely recommended
ECMO: Consider as a rescue therapy for severe, refractory hypoxemia or hypercapnia despite optimal mechanical ventilation.
Supportive Care:
Hemodynamic support: Maintain adequate perfusion with vasopressors if needed
Nutrition: Early enteral nutrition, advanced cautiously
Infection control: Strict hand hygiene, ventilator-associated pneumonia (VAP) prevention bundles
Fluid management: Avoid fluid overload, monitor urine output and daily weights
Sedation and analgesia: Maintain comfort while minimizing over-sedation.
Complications
Early Complications:
Ventilator-associated pneumonia (VAP)
Barotrauma and pneumothorax
Airway injury
Hemodynamic instability
Acute kidney injury
Multi-organ dysfunction syndrome (MODS).
Late Complications:
Prolonged mechanical ventilation dependence
Tracheomalacia
Subglottic stenosis
Pulmonary fibrosis
Ventilator-associated lung injury (VALI)
Long-term neurodevelopmental deficits
Post-intensive care syndrome (PICS).
Prevention Strategies:
Adherence to lung-protective ventilation strategies
Judicious fluid management
Early mobilization
Oral care and head elevation for VAP prevention
Regular assessment for sedation and pain
Prompt recognition and management of complications.
Prognosis
Factors Affecting Prognosis:
Severity of ARDS (oxygenation index, PEEP requirement)
Underlying etiology (sepsis-associated ARDS often has worse prognosis)
Presence of comorbidities
Age at onset
Timeliness and appropriateness of management
Availability of advanced therapies like ECMO.
Outcomes:
Mortality rates are significant but have decreased with improved critical care
Survivors may experience long-term respiratory and neurocognitive sequelae
Recovery can take weeks to months.
Follow Up:
Regular pulmonary follow-up is essential for survivors to monitor for residual lung disease, airway complications, and functional recovery
Neurodevelopmental assessments may be indicated in younger children.
Key Points
Exam Focus:
Understand the PALICC criteria for pediatric ARDS diagnosis and severity classification
Key principles of lung-protective ventilation in children (low tidal volume, permissive hypercapnia, PEEP titration)
Indications and benefits of prone positioning
Recognition of complications and their management
ECMO as a rescue therapy.
Clinical Pearls:
Always consider aspiration as a cause of ARDS in children
Be meticulous with fluid balance
fluid overload worsens pulmonary edema
Titrate PEEP based on oxygenation and compliance, not just a fixed number
Prone positioning can be very effective for hypoxemia but requires vigilant nursing care.
Common Mistakes:
Over-ventilation with high tidal volumes
Inadequate PEEP or excessive PEEP leading to volutrauma
Failing to consider proning for moderate-severe ARDS
Aggressive fluid resuscitation in the setting of pulmonary edema
Delayed recognition of sepsis as an underlying trigger for ARDS.