Surfactant Replacement Therapy

Summary
Introduction
Preparation
Dosage
Procedure
Post-dosing
Complications
Areas of Uncertainty in Clinical Practice

Summary

early administration of surfactant to intubated infants with RDS is desirable
when considering surfactant therapy prior to NICU transfer consultation with a neonatologist at the receiving NICU or the NETS consultant will facilitate care

Introduction

Consider using Surfactant when

presumed diagnosis is RDS (on clinical grounds or CXR) and
infant is intubated, regardless of gestation and requiring FiO₂ > 40%

Treatment is not usually commenced if these criteria are only fulfilled after the infant is 48 hours old.

Preparation

Access to X-ray and blood gas facilities is essential when considering the use of surfactant therapy.
Preparation includes

correction of hypothermia, hypoglycaemia, acidosis , and hypovolaemia are essential aspects of treatment
antibiotics (see RDS Section)
arterial blood gas assessment is required after commencing assisted ventilation; the placement of an arterial line is desirable, but optional
placement of a saturation monitor
a CXR should be performed to confirm diagnosis and check position of endotracheal (ET) tube prior to giving surfactant

Dosage

Curosurf 100mg/kg

Survanta, 4mL/kg

Given via a gavage tube cut so that the tip lies 1cm above the end of the endotracheal tube.
Do not shake the vial. Warm the dose to room temperature before administration (this will take about 20 minutes).

Note. When based on the infant's weight, a vial of Survanta may supply more than one dose, withdraw required dose and the remainder in a second syringe. This then must be capped, labelled and refrigerated with the empty vial so that this can be sent with the infant to the receiving NICU. As Survanta contains no preservatives, aseptic technique must be used.

Procedure

The infant is placed supine and surfactant given as quickly as tolerated so that the total dose is usually given over 3 - 5 minutes. Surfactant can occlude the ET tube and it may be necessary to cease dosage until the tube is cleared and chest wall movement resumes. Ventilator support or inspired oxygen may need to be temporarily increased. At high ventilator rates (>40) regurgitation of surfactant may occur in the expiratory circuit, this can be remedied by smaller boluses and/or by reducing the ventilator rate.

Post Dosing

document oxygen saturation, pO2, pCO2, ventilator settings, FiO2, and notable events every 10 minutes for 30 minutes. Then revert to normal frequency of observations
avoid suctioning the endotracheal tube for 2 hours post-administration unless clear-cut signs of airway obstruction are present. If during or immediately after Surfactant administration oxygen saturation falls associated with lack of chest movement, increase the PIP until good chest movement is observed, then once condition improves try to reduce PIP to original levels
marked improvements may occur within minutes of administration. Therefore, frequent and careful clinical observation and monitoring of oxygenation are essential to avoid hyper-oxygenation or exposure to excessive peak inspiratory pressures
repeat arterial blood gas measurement 30 minutes after dosing with surfactant

Complications

pneumothorax - due to sudden changes in pulmonary compliance if ventilator settings are not appropriately changed
pulmonary haemorrhage - low incidence, but reported, best not to decrease PEEP below 5cm H₂O

Areas of Uncertainty in Clinical Practice

Prophylactic versus Rescue therapy. Prophylactic use of surfactant for infants judged to be 'at risk' of developing respiratory distress syndrome (intubated infants less than 30 weeks gestation) has been demonstrated to improve clinical outcome. Infants have less pneumothoraces, less pulmonary interstitial emphysema and a lower mortality.