minimally invasive surfactant therapy in preterm
TRANSCRIPT
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Catheter withdrawn CPAP recommenced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