Neonatal PhysiologyNeonatal Physiology

Tulane Pediatric SurgeryTulane Pediatric Surgery

TopicsTopics

Fluids and ElectrolytesFluids and Electrolytes CardiopulmonaryCardiopulmonary Temperature RegulationTemperature Regulation JaundiceJaundice Host DefensesHost Defenses Surgical Stress ResponseSurgical Stress Response

Fluids and ElectrolytesFluids and Electrolytes

GlucoseGlucose– PlacentalPlacental– Glycogen StorageGlycogen Storage– GluconeogenesisGluconeogenesis– HypoglycemiaHypoglycemia

SGASGA Surgical PtsSurgical Pts

– HyperglycemiaHyperglycemia

Fluids and ElectrolytesFluids and Electrolytes

CalciumCalcium– Placental DiffusionPlacental Diffusion

75% third trimester75% third trimester

– Limited StoresLimited Stores– Renal ImmaturityRenal Immaturity– HypoparathyroidismHypoparathyroidism– Citrate can bind and decrease CaCitrate can bind and decrease Ca

Fluids and ElectrolytesFluids and Electrolytes

MagnesiumMagnesium– Associated with CalciumAssociated with Calcium– Growth RetardationGrowth Retardation– Maternal DiabetesMaternal Diabetes– Exchange TransfusionsExchange Transfusions

Fluids and ElectrolytesFluids and Electrolytes

Blood VolumeBlood Volume– Highest – DeliveryHighest – Delivery

Cord ClampingCord Clamping

– PolycythemiaPolycythemia Hct>65Hct>65 DiabetesDiabetes ToxemiaToxemia SGASGA Partial ExchangePartial Exchange

Fluids and ElectrolytesFluids and Electrolytes

Hemolytic AnemiaHemolytic Anemia– Maternal AntibodiesMaternal Antibodies– Direct CoombsDirect Coombs– Rh most commonRh most common– Congenital InfectionsCongenital Infections– SS DzSS Dz

Fluids and ElectrolytesFluids and Electrolytes

AnemiaAnemia– Premature InfantsPremature Infants– ErythropoeitinErythropoeitin

Fluids and ElectrolytesFluids and Electrolytes

HemoglobinHemoglobin– 80% Fetal80% Fetal– Erythropoeisis 2-3 monthsErythropoeisis 2-3 months– P50 Adult Hgb – 27 mmHgP50 Adult Hgb – 27 mmHg– P50 Fetal Hgb – 8 mmHgP50 Fetal Hgb – 8 mmHg

JaundiceJaundice

HemolysisHemolysis Glucoronyl TransferaseGlucoronyl Transferase Unconjugated HyperbilirubinemiaUnconjugated Hyperbilirubinemia Peaks 3Peaks 3rdrd Day – 6-7mg/dl Day – 6-7mg/dl Resolves Day 10Resolves Day 10

JaundiceJaundice

Non PhysiologicNon Physiologic– Breast FeedingBreast Feeding– Hemolytic DiseaseHemolytic Disease– HypothyroidHypothyroid– Pyloric StenosisPyloric Stenosis– Crigler-NajarCrigler-Najar– Extravascular BloodExtravascular Blood– Biliary AtresiaBiliary Atresia– HepatitisHepatitis

JaundiceJaundice

Non-PhysiologicNon-Physiologic– Conjugated > 2mg/dlConjugated > 2mg/dl– Rises > 5mg/dl/dayRises > 5mg/dl/day– Born JaundicedBorn Jaundiced– Doesn’t ResolveDoesn’t Resolve

Temperature RegulationTemperature Regulation

EvaporationEvaporation ConductionConduction ConvectionConvection RadiationRadiation

Temperature RegulationTemperature Regulation

Humidified EnvironmentsHumidified Environments– IncubatorIncubator– Ventilator CircuitsVentilator Circuits

Radiant WarmersRadiant Warmers– Dry HeatDry Heat– Increased insensible lossesIncreased insensible losses

Clothes/BlanketsClothes/Blankets

Temperature RegulationTemperature Regulation

HypothermiaHypothermia– HypoglycemiaHypoglycemia– VasoconstrictionVasoconstriction– CoagulopathyCoagulopathy– Emergence from AnesthesiaEmergence from Anesthesia

Renal FunctionRenal Function

Low GFRLow GFR Better at 2 weeksBetter at 2 weeks Normal at 1-2 yearsNormal at 1-2 years Decreased Concentrating AbilityDecreased Concentrating Ability

– 600mOsm600mOsm

Insensitive to ADHInsensitive to ADH

CardiopulmonaryCardiopulmonary

Fetal CirculationFetal Circulation– Right to Left ShuntsRight to Left Shunts

Foramen OvaleForamen Ovale Ductus ArteriosusDuctus Arteriosus

– HypoxemiaHypoxemia– HypercarbiaHypercarbia– AcidosisAcidosis

CardiopulmonaryCardiopulmonary

Persistent Fetal CirculationPersistent Fetal Circulation– SepsisSepsis– Meconium AspirationMeconium Aspiration– Congenital Diaphragmatic HerniaCongenital Diaphragmatic Hernia– IdiopathicIdiopathic– TreatmentTreatment

VentilationVentilation PharmacologyPharmacology ECMOECMO

CardiopulmonaryCardiopulmonary

Surfactant DeficiencySurfactant Deficiency– PrematurePremature– Alveolar StabilityAlveolar Stability– Exogenous AdministrationExogenous Administration

Host DefensesHost Defenses

Cellular ImmunityCellular Immunity– WBCsWBCs

PhagocytosisPhagocytosis AdherenceAdherence KillingKilling Decreased StoresDecreased Stores Poor Stem Cell ProductionPoor Stem Cell Production

Host DefensesHost Defenses

ImmunoglobulinsImmunoglobulins– IgG crosses the placentaIgG crosses the placenta– Poor Response to Antigen ChallengePoor Response to Antigen Challenge

IgA and IgMIgA and IgM No type specific AntibodiesNo type specific Antibodies

– Decreased Complement System FunctionDecreased Complement System Function– Increased Mortality with Pyogenic Bacterial Increased Mortality with Pyogenic Bacterial

InfectionsInfections

Surgical Stress ResponseSurgical Stress Response

Initially Poorly UnderstoodInitially Poorly Understood– Crude MonitoringCrude Monitoring– Few Outcome StudiesFew Outcome Studies

MythsMyths– Anesthetics – Unsafe/Not ApprovedAnesthetics – Unsafe/Not Approved– PainPain– Could Anesthesia Blunt Surgical Stress Could Anesthesia Blunt Surgical Stress

Response?Response?

Surgical Stress ResponseSurgical Stress Response

Measured Catecholamines, Insulin, Cortisol.Measured Catecholamines, Insulin, Cortisol. Adult PhysiologyAdult Physiology Levels Decreased when Anesthesia Levels Decreased when Anesthesia

AdministeredAdministered