Overview
Definition:
Surfactant administration is a critical intervention for neonates with Respiratory Distress Syndrome (RDS), primarily caused by surfactant deficiency in premature lungs
It aims to reduce surface tension in the alveoli, preventing collapse and improving gas exchange
The INSURE (Intubation-Surfactant-Extubation) and LISA (Less Invasive Surfactant Administration) techniques represent evolving approaches to deliver exogenous surfactant.
Epidemiology:
RDS affects a significant proportion of premature infants, with incidence inversely proportional to gestational age
It remains a leading cause of morbidity and mortality in neonates
The choice of surfactant administration technique has implications for ventilator-associated pneumonia (VAP) and other morbidities.
Clinical Significance:
Effective surfactant therapy significantly improves outcomes in preterm infants with RDS, reducing the need for mechanical ventilation, duration of oxygen therapy, and incidence of air leaks and chronic lung disease
Understanding and mastering these techniques are crucial for pediatric residents preparing for DNB and NEET SS examinations.
Insure Technique
Description:
The INSURE technique involves brief intubation of the neonate, administration of surfactant directly into the trachea via an endotracheal tube (ETT), followed by prompt extubation to nasal continuous positive airway pressure (nCPAP).
Procedure Steps:
1
Rapid sequence induction for intubation
2
Confirmation of ETT placement
3
Administration of exogenous surfactant (e.g., poractant alfa, calfactant alfa) via ETT using a catheter or syringe
4
Immediate extubation to nCPAP support
5
Close monitoring of respiratory status.
Advantages:
Ensures direct delivery of surfactant to the lungs
Can be performed quickly by experienced teams
Directly visualized placement via ETT
Effective in neonates requiring immediate ventilatory support.
Disadvantages:
Requires intubation and extubation, which can cause stress and hypoxemia
Increased risk of VAP compared to less invasive methods
Requires skilled personnel for rapid execution.
Indications:
Neonates with moderate to severe RDS requiring immediate ventilatory support
Infants with gestational age < 30 weeks
Failure of nCPAP alone to maintain adequate oxygenation
Cases where precise surfactant delivery is paramount.
Lisa Technique
Description:
LISA involves administering surfactant to a spontaneously breathing infant via a thin catheter or nasogastric tube, often while the infant is receiving nCPAP, without endotracheal intubation.
Procedure Steps:
1
Infant is on nCPAP
2
A thin catheter or feeding tube is passed into the trachea, often guided by laryngoscopy or bronchoscopy
3
Surfactant is instilled through the catheter
4
Catheter is removed while nCPAP is maintained
5
Infant continues on nCPAP support.
Advantages:
Avoids intubation and extubation, reducing physiological stress and risk of VAP
Supports spontaneous breathing
Potentially lower rates of air leak and chronic lung disease
Can be performed in spontaneously breathing infants failing nCPAP.
Disadvantages:
Requires skillful catheterization of the trachea, which can be challenging
Direct visualization of lung distribution may be limited
May not be suitable for infants requiring immediate positive pressure ventilation.
Indications:
Premature infants with mild to moderate RDS who are breathing spontaneously but failing nCPAP alone
Infants who have been extubated after initial INSURE therapy but require further surfactant
As an alternative to INSURE in select cases.
Comparative Analysis
Evidence Summary:
Studies suggest LISA may be associated with lower rates of VAP and chronic lung disease compared to INSURE
However, efficacy in terms of initial oxygenation and reduction in mechanical ventilation duration is comparable between techniques when performed appropriately
The choice often depends on institutional protocols, operator experience, and infant's clinical status.
Vapi Rates:
LISA has shown a trend towards lower rates of VAP in meta-analyses, likely due to the avoidance of intubation
Further research is ongoing to solidify these findings.
Chronic Lung Disease:
Some studies indicate a reduced risk of BPD with LISA, possibly related to less lung injury from intubation/ventilation
Long-term respiratory outcomes are a key area of investigation.
Practical Considerations:
INSURE may be faster and more readily achievable in emergent situations
LISA requires specific equipment and expertise for trans-nasal or trans-tracheal catheterization
Both techniques require precise dosage and timely administration of surfactant.
Diagnostic Approach
History Taking:
Gestational age
Maternal history (e.g., chorioamnionitis, diabetes)
Antenatal steroids given? Onset of respiratory symptoms (tachypnea, grunting, retractions, cyanosis)
Duration of symptoms.
Physical Examination:
Tachypnea, increased work of breathing (subcostal and intercostal retractions, xiphoid retraction, nasal flaring)
Grunting
Cyanosis
Decreased breath sounds
Possible crackles
Vital sign abnormalities (hypoxia, tachycardia).
Investigations:
Chest X-ray: Diffuse, bilateral, reticulogranular opacities with air bronchograms are characteristic of RDS
Arterial Blood Gas (ABG): Hypoxemia (low PaO2), hypercapnia (high PaCO2), and respiratory acidosis (low pH)
Complete Blood Count (CBC) and blood cultures to rule out sepsis.
Differential Diagnosis:
Transient Tachypnea of the Newborn (TTN)
Pneumonia
Pneumothorax
Meconium Aspiration Syndrome
Congenital anomalies (e.g., diaphragmatic hernia, cystic adenomatoid malformation)
Persistent Pulmonary Hypertension of the Newborn (PPHN).
Management Principles
Initial Management:
Prompt recognition of respiratory distress
Support with oxygen therapy, often via nCPAP
Stabilization of the infant
Assessment of severity and indication for surfactant.
Surfactant Therapy Indications:
Gestational age < 30 weeks
Moderate to severe RDS requiring FiO2 > 0.3-0.4 to maintain SpO2 > 88-90%
Presence of clinical signs of RDS and radiographic confirmation
Failure of nCPAP alone to maintain adequate oxygenation.
Exogenous Surfactants:
Available preparations include poractant alfa (Curosurf®), calfactant alfa (Infasurf®), and beractant (Survanta®)
Dosages and administration protocols vary by preparation and technique.
Supportive Care:
Mechanical ventilation if nCPAP and surfactant are insufficient
Monitoring of fluid balance, electrolytes, and temperature
Nutritional support
Close observation for complications.
Complications
Early Complications:
Hypoxemia or hypercapnia despite treatment
Air leaks (pneumothorax, pneumomediastinum)
Pulmonary hemorrhage
Surfactant reflux into the ETT during INSURE
Bradycardia or desaturation during administration.
Late Complications:
Bronchopulmonary Dysplasia (BPD) / Chronic Lung Disease of Infancy
Necrotizing Enterocolitis (NEC)
Retinopathy of Prematurity (ROP)
Intraventricular Hemorrhage (IVH)..
Prevention Strategies:
Antenatal steroids for mothers at risk of preterm delivery
Judicious use of mechanical ventilation
Careful fluid management
Minimizing lung injury by achieving appropriate tidal volumes and pressures
Prompt recognition and management of complications.
Key Points
Exam Focus:
DNB/NEET SS will test the understanding of indications for surfactant, differences between INSURE and LISA, advantages/disadvantages of each, common surfactant preparations, and initial management of RDS
Be prepared to discuss complications and prevention strategies.
Clinical Pearls:
Ensure accurate gestational age assessment for surfactant indication
Timeliness of surfactant administration is crucial
For LISA, good laryngoscopic skills are essential
Always monitor oxygen saturation and respiratory effort closely post-administration.
Common Mistakes:
Delayed surfactant administration
Incorrect dosage or administration technique
Failure to recognize signs of severe RDS requiring surfactant
Over-reliance on one technique without considering infant's status
Inadequate follow-up of respiratory status post-intervention.