CPAP A GENTLE VENTILATIONDR ASHOK MODIMD, DNB, MRCP(UK)CONSULTANT NEONATAL INTENSIVISTBhagirathi Neotia Woman & Child Care Centre

CONTENTSIntroductionHistorical aspectsHow it worksMethodsIndicationsWeaningAdverse effects

IntroductionRespiratory distress in a just born baby- bad news! For doctors Inconvenience, complications(BPD)More so for family death, handicap, costSolution CPAPDoctors convenient, less likely to go wrongFamily baby saved, low costDo I need to tell more?Continuous distending pressure to upper & lower airways, spontaneously breathing, throughout

What is CPAP ?A technique of airway Management in which :-1. Positive intrapulmonary pressure is applied artificially to the airways , whereby Distending Pressure is created in the Alveoli 2. Spontaneously breathing baby 3. Throughout the respiratory cycle

Historical aspectsHarrison 1st increased alveolar pressure during expiration in RDS; Abolition of the grunt in RDS deteriorationGregory et al(1971) used CPAP 1st in spontaneously breathing neonate in RDSLast 3 decades long way to newer devices with better knowledge of physiology & bio-physics

What does it do?Prevents alveolar atelectasis, enhances & maintains FRCDecreases total airway resistanceRegularises breathing patternImprovement in surfactant metabolismSplints chest wall, airways & PharynxReduces work of breathing

What does it do?Results in reopening of collapsed/unstable alveoli - Increased surface area for gas exchangePreserves surfactant esp if applied earlyPrevents Intrapulmonary shuntingNet result improved oxygenation & ventilation

How to deliver CPAPDelivery of continuous positive airway pressure requires 3 components

1. Flow circuit(warm & humidified)

2. An airway interface

3. A positive pressure system

Airway InterfaceSingle nasal prongsBinasal prongs(Short & Long)Nasopharyngeal prongsEndotracheal tubeHead boxes, nasal cannulae, face masksShort binasal prongs most effective, least invasive

Positive pressure systemFluid column(Bubble CPAP)Resistance applied at the expiratory valve e.g Draeger / VentilatorPressure generation at nasal levelCPAP generation in the immediate vicinity of nasal airway by converting kinetic energy e.g Infant flow driver

DEVICESInfant Flow Driver unique fluid mechanics(fluidic flip action) Bubble CPAP oscillatory vibrationsInfant Ventilator with CPAP modeWhich is the best?

Optimal pressureNo compelling DataTraditional 4 6 cm of waterHowever some studies as high as 10 cm H2OTailored to babys needsIncrements by 1 cm of waterGuided by CXR

INDICATIONSMild to moderate RDSApnoea of prematurityAfter extubationAlternative to mechanical ventilation ( INSURE)Presence of poorly expanded or infiltrated lung fields on CXRTracheomalacia or abnormalities of lower airways

CONTRA-INDICATIONSDefinite need for intubation & VentilationUpper airway anomaly e.g choanal atresia, cleft lip & palate, TOFCardiovascular instability & impending arrestUnstable respiratory driveUntreated CDHWhen CPAP is failingBronchiolitis

Monitoring & CareMinimal handling/SedationNasal prongs of right size in place(FIXATION)Orogastric tubeCare of the naresChange of postureVitals & Continuous pulse oximetryBlood gas, haematological, radiological & biochemical monitoring

Is CPAP Helping?Reduction in respiratory rateStabilization or reduction in Fio2Resolution of gruntingReduction in degree of sternal & intercostal recession

When is CPAP failingRecurrent apnoeic attacksSpontaneous episodes of desaturationIncreasing oxygen requirements Worsening respiratory distressAgitation not relieved by simple measures Worsening blood gases

WEANINGOnce baby very stable with minimal respiratory distress, normal blood gas & improving CXRFio2 gradually weaned to 40 50%Then pressure decreased in steps of 1 cm of water until 3 4 cm

Not without its complicationsDo not take CPAP lightly!Pulmonary air leaksExcessive pressure- compromise o2Abdominal distensionHypotensionLocal excoriation, scarring, deformity

Setting an simple CPAP

To concludeGentle & poor mans ventilationEasy to set up & minimal trainingSave babies with RDS in developing countries vs headbox O2Lots of unanswered questions yet Optimal deviceIdeal pressure

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