Acute Bronchiolitis With ICU Management in Children

Topic Introduction Etiology Pathophysiology Clinical Presentation Diagnosis Management Complications Prognosis

Introduction to Acute Bronchiolitis in Children

Acute bronchiolitis is a common lower respiratory tract infection in infants and young children, typically affecting those under 2 years of age. It is characterized by inflammation and congestion in the small airways (bronchioles) of the lung. This condition is most prevalent during winter and early spring months.

Key points:

• Most common cause of hospitalization in infants
• Peak incidence occurs between 3-6 months of age
• Accounts for significant healthcare burden annually
• Understanding its management is crucial for pediatricians and general practitioners

Etiology of Acute Bronchiolitis

Acute bronchiolitis is primarily a viral infection. The most common causative agents include:

1. Respiratory Syncytial Virus (RSV): Responsible for 50-80% of cases
2. Human Metapneumovirus: Second most common cause
3. Parainfluenza viruses
4. Influenza viruses
5. Adenoviruses
6. Rhinoviruses

Risk factors for severe bronchiolitis include:

• Prematurity (gestational age < 37 weeks)
• Chronic lung disease
• Congenital heart disease
• Immunodeficiency
• Young age (< 12 weeks)
• Exposure to tobacco smoke
• Lack of breastfeeding

Pathophysiology of Acute Bronchiolitis

The pathophysiology of acute bronchiolitis involves several stages:

1. Viral infection: The virus infects and replicates in the epithelial cells of the upper respiratory tract.
2. Spread to lower airways: The infection spreads to the lower respiratory tract, including the bronchioles.
3. Inflammation: This leads to inflammation of the bronchiolar epithelium, causing edema and increased mucus production.
4. Obstruction: The inflamed airways become obstructed with cellular debris, mucus, and edema.
5. Air trapping: Partial obstruction of airways can lead to air trapping and atelectasis.
6. Increased work of breathing: The child must work harder to breathe due to airway obstruction and decreased gas exchange.

This process results in the characteristic clinical presentation of wheezing, cough, and respiratory distress.

Clinical Presentation of Acute Bronchiolitis

The clinical presentation of acute bronchiolitis typically follows a pattern:

1. Prodromal phase:
   • Rhinorrhea
   • Nasal congestion
   • Low-grade fever
2. Acute phase (2-3 days later):
   • Persistent cough (often paroxysmal)
   • Tachypnea
   • Wheezing
   • Increased work of breathing (retractions, nasal flaring)
   • Irritability
   • Poor feeding

Severe cases may present with:

• Cyanosis
• Apnea (especially in young infants)
• Respiratory failure

Physical examination findings may include:

• Tachypnea
• Subcostal and intercostal retractions
• Nasal flaring
• Diffuse wheezing and crackles on auscultation
• Prolonged expiratory phase
• Hyperinflation of the chest

Diagnosis of Acute Bronchiolitis

The diagnosis of acute bronchiolitis is primarily clinical, based on history and physical examination. However, certain investigations may be helpful:

Clinical Diagnosis:

• Typical history of viral prodrome followed by lower respiratory symptoms
• Age < 2 years, especially during RSV season
• Physical examination findings consistent with bronchiolitis

Investigations:

1. Chest X-ray: Not routinely recommended, but may be considered in severe cases or if complications are suspected. Typical findings include hyperinflation, patchy atelectasis, and peribronchial thickening.
2. Viral testing: Not routinely needed for diagnosis but may be useful for cohorting in hospital settings. Rapid antigen detection tests or PCR for RSV and other viruses may be used.
3. Pulse oximetry: To assess oxygenation status.
4. Blood tests: Not routinely indicated but may be considered in severe cases to rule out bacterial infection.

Differential Diagnosis:

• Asthma
• Pneumonia
• Cystic fibrosis
• Foreign body aspiration
• Congenital heart disease

Management of Acute Bronchiolitis

The management of acute bronchiolitis is largely supportive, focusing on maintaining hydration and oxygenation. Treatment approaches include:

Supportive Care:

• Hydration: Ensure adequate fluid intake. IV fluids may be necessary if oral intake is poor.
• Oxygen therapy: Provide supplemental oxygen if SpO2 < 90-92% (threshold may vary by institution).
• Nasal suctioning: To clear secretions, especially before feeds.
• Positioning: Elevate head of bed to 30-45 degrees.

Pharmacological Interventions:

Most pharmacological interventions have limited evidence of benefit:

• Bronchodilators: Not routinely recommended. A trial of inhaled bronchodilators may be considered, but should be discontinued if no response.
• Corticosteroids: Not recommended for routine use.
• Hypertonic saline: May be beneficial in inpatient settings, but evidence is mixed.
• Antibiotics: Not indicated unless there's strong suspicion of secondary bacterial infection.

Admission Criteria:

• Hypoxemia (SpO2 < 90-92% on room air)
• Moderate to severe respiratory distress
• Dehydration or poor feeding
• Apnea
• Young age (< 3 months)
• Presence of comorbidities

Prevention:

• Good hand hygiene
• Avoiding exposure to tobacco smoke
• Breastfeeding
• Palivizumab prophylaxis for high-risk infants during RSV season

Complications of Acute Bronchiolitis

While most cases of acute bronchiolitis resolve without complications, some patients may develop:

• Respiratory failure: Requiring mechanical ventilation
• Dehydration: Due to poor oral intake and increased respiratory effort
• Secondary bacterial infections: Such as otitis media or pneumonia
• Apnea: Especially in young infants or those born prematurely
• Atelectasis: Collapse of lung segments due to mucus plugging

Long-term complications may include:

• Recurrent wheezing: Some children may experience recurrent wheezing episodes for several years after bronchiolitis
• Increased risk of asthma: There's an association between severe bronchiolitis in infancy and subsequent development of asthma

Prognosis of Acute Bronchiolitis

The prognosis for most children with acute bronchiolitis is excellent:

• Most cases are self-limiting and resolve within 1-2 weeks
• The majority of children can be managed at home with supportive care
• Hospital admission is required in about 2-3% of cases
• Mortality is rare in developed countries, occurring in <1% of hospitalized infants

Factors associated with worse prognosis include:

• Young age (< 3 months)
• Prematurity
• Underlying cardiopulmonary disease or immunodeficiency
• Severe presentation requiring intensive care

Long-term outcomes:

• About 30-40% of children may have recurrent wheezing episodes in the first few years after bronchiolitis
• The link between bronchiolitis and subsequent asthma development is complex and not fully understood

ICU Management Introduction ICU Admission Criteria Initial Assessment Respiratory Support Fluid Management Nutrition Medication Management Monitoring and Surveillance ICU-Specific Complications ICU Discharge Criteria

Introduction to ICU Management of Acute Bronchiolitis

While most cases of acute bronchiolitis can be managed in general pediatric wards or at home, a small percentage of children require intensive care unit (ICU) admission due to severe disease or complications. ICU management focuses on providing advanced respiratory support, maintaining fluid balance, and preventing complications.

Key points:

• Approximately 2-6% of infants hospitalized with bronchiolitis require ICU admission
• Main goals are to support oxygenation and ventilation while allowing for lung recovery
• Management requires a multidisciplinary approach involving intensivists, respiratory therapists, and specialized nursing care
• Length of ICU stay can vary widely, from a few days to several weeks in severe cases

ICU Admission Criteria for Acute Bronchiolitis

Criteria for ICU admission may vary between institutions but generally include:

1. Respiratory failure:
   • Severe respiratory distress despite maximal ward-based therapy
   • PaO2 < 60 mmHg or PaCO2 > 50 mmHg on room air
   • Need for FiO2 > 0.6 to maintain SpO2 > 92%
2. Impending respiratory failure:
   • Rapidly worsening respiratory distress
   • Significant work of breathing (severe retractions, nasal flaring, grunting)
3. Need for advanced respiratory support:
   • High-flow nasal cannula (HFNC) > 2 L/kg/min
   • Continuous positive airway pressure (CPAP)
   • Mechanical ventilation
4. Apnea:
   • Recurrent or prolonged apneic episodes
   • Apnea requiring bag-mask ventilation
5. Cardiovascular instability:
   • Shock requiring fluid resuscitation or inotropic support
   • Significant bradycardia or tachycardia
6. Altered mental status:
   • Lethargy or decreased responsiveness

Initial Assessment in the ICU

Upon admission to the ICU, a comprehensive assessment should be performed:

1. Airway and Breathing:
   • Assess work of breathing, respiratory rate, and use of accessory muscles
   • Auscultate for breath sounds, wheezing, and crackles
   • Check oxygen saturation and arterial blood gases
2. Circulation:
   • Assess heart rate, blood pressure, and peripheral perfusion
   • Check capillary refill time
3. Neurological status:
   • Assess level of consciousness
   • Check for signs of increased intracranial pressure
4. Hydration status:
   • Check skin turgor, mucous membranes, and urine output
   • Assess for signs of dehydration or fluid overload
5. Laboratory investigations:
   • Complete blood count
   • Electrolytes, blood urea nitrogen, creatinine
   • Liver function tests
   • Blood culture if sepsis is suspected
   • Viral PCR panel
6. Imaging:
   • Chest X-ray to assess for complications like pneumothorax or atelectasis

Respiratory Support in ICU

Respiratory support is the cornerstone of ICU management for severe bronchiolitis. The level of support is tailored to the patient's needs:

1. High-Flow Nasal Cannula (HFNC):
   • Often the first-line respiratory support in ICU
   • Typically start at 2 L/kg/min, can be increased up to 3 L/kg/min
   • FiO2 titrated to maintain SpO2 92-97%
2. Continuous Positive Airway Pressure (CPAP):
   • Consider if HFNC is insufficient
   • Start at 5-7 cmH2O, can increase up to 10-12 cmH2O
   • Monitor for air leak and gastric distension
3. Non-invasive Ventilation (NIV):
   • Bi-level positive airway pressure (BiPAP) may be used in some cases
   • Typically EPAP 4-8 cmH2O, IPAP 10-16 cmH2O
4. Invasive Mechanical Ventilation:
   • Indicated for apnea, respiratory failure despite non-invasive support, or altered mental status
   • Use lung-protective strategies:
     • Tidal volume 5-7 mL/kg ideal body weight
     • PEEP 5-8 cmH2O
     • Plateau pressure < 30 cmH2O
   • Consider permissive hypercapnia (pH > 7.25)
   • Prone positioning may be beneficial in severe cases

Note: Avoid routine use of inhaled bronchodilators or corticosteroids as they have not shown consistent benefit in bronchiolitis.

Fluid Management in ICU

Proper fluid management is crucial in ICU care of bronchiolitis patients:

1. Initial assessment:
   • Evaluate for dehydration or fluid overload
   • Check electrolytes, especially sodium
2. Maintenance fluids:
   • Calculate based on Holliday-Segar method, but consider restricting to 70-80% of calculated maintenance
   • Use isotonic fluids (e.g., 0.9% NaCl with 5% dextrose)
3. Correction of dehydration:
   • If dehydrated, provide fluid boluses cautiously (5-10 mL/kg)
   • Reassess frequently to avoid fluid overload
4. Monitoring:
   • Strict input/output charting
   • Daily weights
   • Regular electrolyte checks
5. Special considerations:
   • Be aware of syndrome of inappropriate antidiuretic hormone secretion (SIADH)
   • Monitor for signs of fluid overload, especially in patients on high-flow oxygen therapy

Nutrition Management in ICU

Maintaining adequate nutrition is important for recovery:

1. Enteral nutrition:
   • Preferred route if the gastrointestinal tract is functional
   • May need to use nasogastric or nasoduodenal feeding if respiratory distress impairs oral feeding
   • Consider continuous feeds to reduce work of breathing associated with large volume feeds
2. Parenteral nutrition:
   • Consider if enteral nutrition is not possible or insufficient
   • Typically initiated if enteral feeding is not expected to be possible for >48-72 hours
3. Caloric goals:
   • Aim for 110-120% of basal metabolic rate to account for increased work of breathing
   • Adjust based on the patient's clinical status and respiratory support

Medication Management in ICU

While pharmacological interventions have limited evidence in bronchiolitis, certain medications may be considered in the ICU setting:

1. Bronchodilators:
   • Not routinely recommended
   • A trial of inhaled albuterol may be considered in children with strong personal/family history of atopy
   • Discontinue if no objective improvement
2. Nebulized hypertonic saline:
   • May help in mucus clearance
   • Typically 3% NaCl, 4 mL every 6 hours
3. Systemic corticosteroids:
   • Not routinely recommended
   • May be considered in children with severe disease and strong history of atopy
4. Antibiotics:
   • Only if strong suspicion of secondary bacterial infection
   • Consider in intubated patients if clinical deterioration occurs
5. Sedation:
   • May be necessary for mechanically ventilated patients
   • Use minimal sedation to allow for spontaneous breathing
   • Common agents: fentanyl, midazolam

Monitoring and Surveillance in ICU

Continuous monitoring is essential for ICU management of bronchiolitis:

1. Cardiorespiratory monitoring:
   • Continuous heart rate, respiratory rate, and oxygen saturation monitoring
   • Regular blood pressure measurements
   • Continuous ECG monitoring
2. Respiratory assessment:
   • Regular clinical assessment of work of breathing
   • End-tidal CO2 monitoring if intubated
   • Arterial or venous blood gases as needed
3. Fluid balance:
   • Strict input/output charting
   • Daily weights
4. Laboratory monitoring:
   • Regular electrolyte checks
   • Complete blood count
   • Liver and kidney function tests
5. Ventilator parameters:
   • For intubated patients, monitor tidal volumes, peak and plateau pressures, PEEP, and FiO2
6. Neurological status:
   • Regular assessment of level of consciousness
   • Monitor for signs of increased intracranial pressure

ICU-Specific Complications

Children with severe bronchiolitis in the ICU are at risk for several complications:

1. Ventilator-Associated Pneumonia (VAP):
   • Implement VAP prevention bundle
   • Monitor for new infiltrates on chest X-ray and clinical deterioration
2. Atelectasis:
   • Common due to mucus plugging
   • May require aggressive chest physiotherapy and suctioning
3. Air leak syndromes:
   • Pneumothorax, pneumomediastinum, or pulmonary interstitial emphysema
   • More common in mechanically ventilated patients
   • Manage with chest tube drainage if significant
4. Acute Respiratory Distress Syndrome (ARDS):
   • Can develop in severe cases
   • Manage with lung-protective ventilation strategies
5. Fluid and electrolyte imbalances:
   • SIADH (Syndrome of Inappropriate Antidiuretic Hormone secretion)
   • Hyponatremia or hypernatremia
   • Require careful fluid management and regular electrolyte monitoring
6. Nosocomial infections:
   • Increased risk due to invasive procedures and prolonged ICU stay
   • Implement strict infection control measures
7. Cardiovascular complications:
   • Myocardial dysfunction in severe cases
   • Pulmonary hypertension, especially in patients with pre-existing cardiac conditions
8. Neurological complications:
   • Encephalopathy due to hypoxia or severe acidosis
   • Seizures, particularly in the context of severe electrolyte imbalances
9. Nutritional deficits:
   • Due to increased metabolic demands and potential feeding difficulties
   • May require aggressive nutritional support
10. Post-extubation stridor:
    • Can occur after prolonged intubation
    • May require treatment with racemic epinephrine and dexamethasone
11. Psychological impact:
    • Stress and anxiety for both patient and family
    • Consider psychological support and clear communication with family

ICU Discharge Criteria

Patients with bronchiolitis may be considered for transfer out of the ICU when:

1. Respiratory status:
   • Stable respiratory rate and work of breathing
   • Oxygen requirement decreased to a level manageable on the ward (typically FiO2 < 0.4)
   • If on HFNC, flow rate reduced to < 2 L/kg/min
   • No significant apnea for at least 24 hours
2. Hemodynamic stability:
   • Normal heart rate and blood pressure for age
   • No need for inotropic support
3. Fluid and nutrition:
   • Adequate oral intake or stable on enteral feeds
   • No significant fluid or electrolyte imbalances
4. Neurological status:
   • Return to baseline level of consciousness
   • No seizures or other neurological complications
5. Laboratory parameters:
   • Improving or normalized blood gas values
   • Stable electrolytes and renal function
6. Monitoring requirements:
   • No need for continuous invasive monitoring
   • Stable on intermittent vital sign checks

Post-ICU care:

• Ensure clear communication with ward team about patient's course and ongoing care needs
• Consider gradual weaning of oxygen support
• Continue respiratory physiotherapy and suctioning as needed
• Provide family education on signs of respiratory distress and when to seek medical attention
• Arrange appropriate follow-up, especially for patients who required mechanical ventilation

Acute Bronchiolitis With ICU Management

1. Q: What is the primary causative agent of acute bronchiolitis in infants? A: Respiratory Syncytial Virus (RSV)
2. Q: What age group is most commonly affected by severe bronchiolitis requiring ICU admission? A: Infants less than 3 months old
3. Q: What are the typical clinical features of severe bronchiolitis? A: Tachypnea, chest retractions, nasal flaring, and hypoxemia
4. Q: What is the gold standard diagnostic test for RSV bronchiolitis? A: RT-PCR of nasopharyngeal secretions
5. Q: What blood gas abnormality is commonly seen in severe bronchiolitis? A: Respiratory acidosis (elevated pCO2)
6. Q: What imaging study is most useful in evaluating severe bronchiolitis? A: Chest X-ray
7. Q: What are the typical chest X-ray findings in bronchiolitis? A: Hyperinflation, peribronchial thickening, and patchy atelectasis
8. Q: What is the primary goal of oxygen therapy in bronchiolitis? A: To maintain oxygen saturation ≥90-92%
9. Q: What is the first-line respiratory support for bronchiolitis in the ICU? A: High-flow nasal cannula (HFNC) oxygen therapy
10. Q: What is the typical flow rate range for HFNC in infants with bronchiolitis? A: 1-2 L/kg/min, up to a maximum of 12-15 L/min
11. Q: What is the next step in respiratory support if HFNC fails? A: Non-invasive ventilation (CPAP or BiPAP)
12. Q: What are the indications for intubation and mechanical ventilation in bronchiolitis? A: Respiratory failure, apnea, or cardiovascular instability
13. Q: What ventilation strategy is preferred for intubated patients with bronchiolitis? A: Lung-protective strategy with low tidal volumes and permissive hypercapnia
14. Q: What is the role of bronchodilators (e.g., albuterol) in bronchiolitis management? A: Limited; not routinely recommended but may be tried in individual cases
15. Q: What is the current recommendation regarding systemic corticosteroids in bronchiolitis? A: Not routinely recommended due to lack of proven benefit
16. Q: What is the role of nebulized hypertonic saline in bronchiolitis management? A: May provide modest benefit in hospitalized infants, but not routinely used in ICU
17. Q: What is the recommended approach to fluid management in severe bronchiolitis? A: Careful fluid balance, often with mild restriction (75-80% of maintenance)
18. Q: What is the role of antibiotics in the management of bronchiolitis? A: Not routinely recommended unless there's strong suspicion of bacterial co-infection
19. Q: What complication can occur due to excessive respiratory effort in bronchiolitis? A: Respiratory muscle fatigue leading to respiratory failure
20. Q: What is the role of chest physiotherapy in ICU management of bronchiolitis? A: Not routinely recommended but may be considered in specific cases (e.g., atelectasis)
21. Q: What is the significance of apnea in infants with bronchiolitis? A: Indicates severe disease and may necessitate ICU admission
22. Q: What metabolic complication can occur in severe bronchiolitis? A: Hyponatremia due to inappropriate ADH secretion
23. Q: What is the role of surfactant therapy in severe bronchiolitis? A: Not routinely recommended; may be considered in select cases of very severe disease
24. Q: What is the typical duration of ICU stay for infants with severe bronchiolitis? A: 3-7 days, depending on severity and complications
25. Q: What long-term respiratory complication is associated with severe bronchiolitis in infancy? A: Increased risk of recurrent wheezing and asthma
26. Q: What is the role of extracorporeal membrane oxygenation (ECMO) in bronchiolitis management? A: Last resort for refractory hypoxemia or severe air leak syndromes
27. Q: What is the recommended method for nutrition support in severe bronchiolitis? A: Enteral nutrition via nasogastric tube if respiratory status allows
28. Q: What is the role of inhaled nitric oxide in bronchiolitis management? A: Not routinely recommended; may be considered in cases with pulmonary hypertension
29. Q: What is the significance of bacterial co-infection in severe bronchiolitis? A: Can worsen prognosis and may require antibiotic treatment
30. Q: What is the role of prone positioning in managing severe bronchiolitis? A: May improve oxygenation in some cases, but not routinely recommended

External Links for Further Reading

• NICE Guidelines on Bronchiolitis in Children
• American Academy of Pediatrics Clinical Practice Guideline on Bronchiolitis
• UpToDate: Bronchiolitis in infants and children: Clinical features and diagnosis
• The Lancet: Bronchiolitis
• New England Journal of Medicine: Viral Bronchiolitis in Children

• Pediatric Acute Respiratory Distress Syndrome in Pediatric Intensive Care Unit
• Pediatric Acute Respiratory Distress Syndrome: Consensus Recommendations
• High-Flow Nasal Cannula Use in Children with Respiratory Distress
• Viral Bronchiolitis in Children
• Nutritional Support in Critically Ill Children