Physiological Response of Newborn to Birth Chapter 23

Neonatal Transition Surfactant production Breathing initiated by mechanical, sensory, chemical, thermal changes. Mechanical- pressure from chest compression, recoil Remaining fluid pulled into interstitial fluid Problems r/t inadequate chest compression

Chemical Stimuli Fetal acidosis, decrease in PO2,increase PCO2 Cord clamped, stress of labor Stimulation of medulla

Thermal and Sensory Shock of cold environment Nerve ending stimulated Cold stress Tactile, auditory and visual stimulation Encourage skin to skin contact

Cardiopulmonary Adaptation Blood flow to lungs established Oxygen saturation Newborn anatomy restricts lung expansion Periodic breathing Obligate nose breathers

Cardiopulmonary Adaptation Clamping of cord, “shut off the hose”, increase in blood pressure Perfusion increased by pulmonary blood flow and dilation pulmonary vessels. Decrease in vascular resistance Pressure change closes foramen ovale Ductus arteriosis closes due to PO2 Ductus venosis closure leads to liver profuse

Cardiac Fx Normal rate BP Most murmurs transient and benign Right ventricle versus left ventricle Pressure gradient changes from left to right

Hemodynamics RBC shorter life span Rise in HCT Stress response Cord clamping Gestational age Presence of hemorrhage Site of blood sample

Temperature Metabolism and O2 consumption increase with heat loss Thin skin, decreased fat Blood vessels close to surface Flexed posture Premature infants

Heat Loss Large body surface – Vessels close to skin Convection- cool air currents, door open Radiation- heat transfers to cooler surface, place cool object on warmer Evaporation-water converted to vapor, wet baby Conduction- loss of heat due to direct contact with object

Thermogenesis Increase in BMR, and activity generate heat Nonshivering thermogenesis (NST) Infant uses stores of brown fat Brown fat metabolized quickly to produce heat Do not chill newborns Cold stress can delay drug metabolism

Hepatic Adaptation Iron stored in fetal liver, last for 6 months Energy crunch caused by labor and loss of maternal glucose Newborn converts from use of carbohydrate metabolism to fat metabolism

Conjugation of Bilirubin Bilirubin is byproduct of breakdown of RBCs In utero bilirubun excreted by placenta Bilirubin needs to be conjugated to be excreted. Enzymes in liver conjugate bilirubin- bacteria transforms into urobilirubin Low levels of glucuronyl transferase and immature liver function

Physiologic Jaundice Normal response 2-3 days after birth Caused by increase volume and RBC destruction Bilirubin not flushed from plasma Bilirubin not conjugated Decreased bacterial flora and motility

Nursing Room environment-avoid pink Head to toe, blanch and assess for yellow Maintain temp Monitor for excretion Feed early Phototherapy for newborns over 13mg/dl

Breastfeeding Jaundice Peaks in 2-3 weeks Composition of breast milk may interfere with conjugation If above 20mg.dl may be asked to cease Continue to pump Reassure moms

Coagulation Some coagulation factors are Vit. K dependent At birth bacteria in colon not present for Vit. K synthesis Dilantin and Coumadin associated with bleeding issues

GI Lactose(carb.),proteins easily digested Starches not easily digested Lack of pancreatic enzyme limits fat digest. Some regurge nl, burp do not overfeed Need 120 cal/kg/day, 5%-10% weight loss. Meconium- debris, dark, tarry Differentiate breast feed from bottle fed

Kidney Fx Inability to concentrate urine Decrease in GFR, unable to diurese quickly Most void within 24 hrs., 6/day Increase 5-25/day after 2 days Blood in female diaper due to pseudomenstruation

Immunity Immunoglobin IgG transferred to fetus, passive acquired immunity Length of immunity to bacteria and virus vary Lack of IgM, fetus susceptible to gram - IgA protects, gi, int, eyes, high concentration in colostrum

Neurological Fx Able to habituate Able to fixate on faces or objects with contrast Blinking reflex Growth is cephalocaudal Reflexes present Defensive motor ability