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P. 1102
P68 Pediatrics
Neonatology Toronto Notes 2019 Persistent Pulmonary Hypertension of
the Newborn
Definition
• persistenceoffetalcirculationasaresultofpersistentelevationofpulmonaryvascularresistance • classifiedasprimary(absenceofriskfactors)orsecondary
Epidemiology
• incidence1.9/1,000livebirths
Clinical Presentation
• usuallypresentswithin12hofbirthwithseverehypoxemia/cyanosis;mayhaveonlymildrespiratory distress
Pathophysiology
• elevatedpulmonarypressurescauseR→LshuntthroughPDA,foramenovale→decreasedpulmonary blood flow and hypoxemia → further pulmonary vasoconstriction
Risk Factors
• secondaryPPHN:asphyxia,meconiumaspirationsyndrome,RDS,sepsis,pneumonia,structural abnormalities (e.g. diaphragmatic hernia, pulmonary hypoplasia)
• morecommonintermorpost-terminfants
Investigations
• measurepre-andpost-ductaloxygenlevels
• hyperoxiatesttoexcludeCHD
• ECG(RVstrain)
• EchorevealsincreasedpulmonaryarterialpressureandaR→LshuntacrossPDAandpatentforamen
ovale; also used to rule out other cardiac defects
Treatment
• maintaingoodoxygenation(SaO2>95%)inat-riskinfants
• O2givenearlyandtaperedslowly,minimizestressandmetabolicdemands,maintainnormalblood
gases, circulatory support
• mechanicalventilation,highfrequencyoscillationinasedatedmuscle-relaxedinfant
• nitricoxide,surfactant
• extracorporealmembraneoxygenationusedinsomecentreswhenothertherapyfails
Respiratory Distress in the Newborn
Clinical Presentation
• tachypnea:RR>60/min;tachycardia:HR>160/min
• grunting,subcostal/intercostalindrawing,nasalflaring • duskiness,centralcyanosis
• decreasedairentry,cracklesonauscultation
Differential Diagnosis of Respiratory Distress
• pulmonary:RDS(respiratorydistresssyndrome),TTN(transienttachypneaofthenewborn), meconium aspiration syndrome, pleural effusion, pneumothorax, congenital lung malformations
• infectious: sepsis, pneumonia
• cardiac:CHD(cyanotic,acyanotic),PPHN
• hematologic:bloodloss,polycythemia
• anatomic:TEF,congenitaldiaphragmatichernia,mucousormeconiumplug,upperairwayobstruction
• metabolic:hypoglycemia,inbornerrorsofmetabolism
• neurologic:CNSdamage(trauma,hemorrhage),drugwithdrawalsyndromes
Investigations
• CXR,ABG(orvenousbloodgasfromumbilicalvenousline) • CBC,bloodcultures,bloodglucose
• ECGifindicated
