Minimally invasive surfactant therapy in preterm

BMJ– FETAL & NEONATAL MEDICINEMARCH 2013

Ojective : to evaluate the applicability & potential effectiveness of a technique of minimal invasive surfactant therapy in preterm infants on cpap

Already known on this topic

Preterm infants managed intially on cpap will go on to require intubation because of respiratory distress related to surfactant defeciency

What this study addsA technique of MIST using narrow bore

vascular catheter inserted into trachea was successfully applied by neonatal physicians at two sites

Administration of surfactantb via MIST resulted in sustained reduction in o2 requirement &decrease in the need in intubation for 25-28 weeks gestation

Outcomes for infants commencing on CPAP coud be further improved if those with significant RDS were to receive exogenous surfactant at an early stage

INSURE limitations has prompted the pursuit of alternative less invasive means of giving surfactant therapy to preterm infants on CPAP

MISTDirect tracheal catherizationFlexible feeding tube positioned in trachea

with Magills forceps

A new alternative method of surfactant delivery via tracheal catherization using a semirigid vascular catheter

Which was found to be practicable with no significant procedural complication s

aiimsTo evaluate the applicability & apparent

safety of the technique

Document the physiologic response to surfactant administration

Comare outcomes of infants receiving MIST with like gestation historical controls

MethodsSite

NICU of ROYAL HOBART HOSPITAL&NICU OF ROYAL WOMEN HOSPITAL

BOTH UNITS USED cpap as initial respiratory support

Study groupsInfants receiving MISTSTUDY conducted b/w june 2009-2011 may Preterm infants b/w 25 &32 completed weeks

of gestation were eligible for inclusion with CPAP &,24 hrs age required cpap pressure of ≥7

Control Data were collected frm infants managed on

CPAP in time period immediately before beginning the study (2006-2009)

Mist procedureSurfactant instilled via tracheal

catheterization On stable babies with HR>120 SPO2>85%A 16 gauge vascular catheter was marked to

indicate desired depth of ninsedtion (25-26 – 1cm )(27-28 wks 1.5 cm)

Direct larygoscopy performed tracheal catheter was inserted beyond vocal cords surfactant given at dose of 100 or 200 mg/kg

Catheter withdrawn CPAP recommenced

Care after MIST included monitoring &treatment of PDA &screening of IVH &ROP

RESULTSTOTAL 61 infants were enrolledInfants at 25-28 weeks gestation received

surfactant via MIST at early age (3hrs)Those at 29 32 weeks gestation (9hrs)

A modest decrease in CPAP pressure was notedafter MIST sustained at least 24 hrs of life

Oxygenation improved after MIST in both gestational ages with reduction in Fio2

Comparedb with historical controls the need for intubation before 72h was considerably reduced after MIST in 25-28 wks

In this study the narrow bore semirigid design of catheter means that, unlike a standard endotracheal tube

It can be passed down the eyeline without obscuring the view of the glottis , with an external diameter less than half that of a 2.5 mm endotracheal tube

Mist catheter passes easily through vocal cords

MIST well tolerated by infants on CPAP , despite receiving no premedication

Surfactant administration via MIST was associated witha more rapid and pronounced improvement in oxygenation

Based on these results large scale RCT OF MIST IS REQUIRED

SURFACTANT REPLACEMENTONE OF THE BEST STUDIED THERAPIES

IN NEONATESurfactants of human,bovine or porcine

origin have been studied

TimingProphylactic treatment of deficiency before

lung injury occurs ,results in better distributon and less lung injury than supplementation once respiratory failureb is severe

ResponseResponse variesThe reasons include timing of treatment &

patient factors such as concurrent illness & degree of of lung maturity

Delayed resuscitationExcessive fluid administrationImproper ventilator stratagies

Combined use of antenatal steroids& post natal surfactant therapy improves neonatal outcome

In established RDS repeated surfactant treatment results in greater improvement in oxygenation& ventilation decreased risk of pneumothorax & improve d survival when compared to single dose therapy

retreatment infants on mechanical ventilation&Pressure >7 Fio2>0.3

administrationSurvanta-beractant bovine dose 4ml/kg(100m/kg) divided in 4 quater

doses

Prophylaxis : give with in 15 min of birth in infats at risk

4 doses can be given no more frequently than every 6hrs

Infasurf (calfactant)3 ml/kg for prophylaxis or rescue therapyMax 3 doses

Curosurf (poractant) Intial dose 2.5 ml/kg 2 susequent doses 1.25ml/kg administered

12hrs apart

complicationsPulmonary hemorrage Occurs in extremely LBW babies MalesWho have clinical evidence of PDA