Newborn Adaptation to Extrauterine Life A systemic approach

Newborn Adaptation to Extrauterine Life A systemic approach to life in this world~

The Lungs u The most important vital organ that needs to be adequately functional in the neonate u Largely dependent on maturation of the fetus u Website on fetal lung development

Fetal maturation: u 20 -24 wks - alveolar ducts appear u 24 -28 wks - alveoli remain primitive u 28 -32 wks - type II (surfactant producing) cells increase u 35 wks - Lecithin production peaks

Role of Surfactant u phospholipid u lung cell maturity (PI) u lowers surface tension (PG) u increased lung compliance u. L/S u Lecithin Ratios (increases) u Sphingomyelin (constant) u <30 wks = low L/S u 30 -32 wks - L/S = 1: 1 u >35 wks - L/S = 2: 1

Adaptation at birthfactors that foster that initial breath u Mechanical– “Vaginal squeeze” is followed by chest recoil after birth. u Chemical – Transient asphyxia at birth results in * decreased p. O 2 * decreased p. H as low as 7. 25 * increased p. CO 2 These changes stimulate chemoreceptors around the aorta and carotid which tells the respiratory center in the medulla to start breathing

Adaptation (cont’d) u Temperature— The drop in temperature from a cozy 98. 6 to 65 -70 F. stimulates the neonate’s CNS to breathe. u Sensory stimuli– all 5 senses are brought to life in the delivery room *Noise in the delivery room *Bright lights in the delivery room *Tactile stimulation– drying off the baby, stroking and caressing by parents, etc. *Smells in the delivery room *Taste when bulb syringe or gloved hand is introduced into mouth, & when mom nurses the first time.

Assessment Parameters-Respiratory System u Quality of respirations-- 30 -60/min. u gasping, irregular, shallow breathing is normal at first u periodic breathing is typical u true apnea= >20 sec. without breathing is abnormal u “wet” lungs– common in the first 5 minutes of life; if persistent, may require De. Lee suctioning

Assessment Parameters-Respiratory System(cont’d) u Obligate nose breathers u Retractions– abdomen & chest wall should rise simultaneously. “Seesaw” movements and expiratory grunting are ominous signs requiring intervention.

Oxygen Transport (p. 797 Olds 8 th ed. ) u 2 types of Hemoglobin in fetus & newborn: u Fetal Hgb: Hb. F— 70 -90%. Has O 2 affinity which means if facilitates O 2 transfer across the placenta and into newborn’s tissues. u Fetal Pa. O 2— 30 -40 mm Hg. u Fetal Hgb level— 17 g/d. L—allows fetus to tolerate relatively low Pa. O 2 in utero, because the absolute O 2 -carrying capacity of the blood is > adult Hgb. u Adult Hgb: Hb. A has O 2 affinity but O 2 release. Hb. A of 13 g/d. L in adult has lower O 2 carrying capacity.

The Heart~ Cardiovascular Adaption u The heart goes through a series of changes: u increased aortic pressure and decreased venous pressure 2 ndary to clamping the umbilical cord u increased systemic pressure and decreased pulmonary artery pressure with initiation of respirations and loss of placenta

u closure of the ductus venosus--fetal structure from umbilical vein to inferior vena cava carrying O 2 from the placenta u closure of foramen ovale--fetal structure that connects the right atrium with the left atrium further allowing right to left shunting during fetal life. u closure of the ductus arteriosus-- fetal structure connecting the pulmonary artery with the aorta allowing right to left shunting during fetal life

Fetal Circulation u Note: the Umbilical Vein carries oxygenated blood from the mother to the inferior vena cava where it mixes with unoxygenated blood from the body. This mixed blood travels through the heart and to the body oxygenating all fetal cells. The unoxygenated blood returns to the mother via the umbilical arteries.

Do you hear a MURMUR? u Occur in 37% of all newborns u 90% are transient due to delayed closure of ducts (PDA &/or PFO) u These types usually disappear by 6 months of age

Vital Sign Averages u Birth weight: 6 -9 lbs. 2500 -4000 g. (wt. Loss of 5 -10% of birth wt. in 1 st 3 -4 days is expected. Should regain birth weight by 2 week check-up. ) u Length: 18 -21 in. (45 -52. 5 cm) u Head Circumference: 13 -14 in. (33 -35 cm) u Chest Circumference: 12 -13 in. (30 -33 cm) should be ~2 -3 cm. < head circumference u Blood Pressure: ave. 78/42 (less for premie, more if crying. * Cause for concern: Diastolic <25 or >60

Vital Sign Averages (cont’d) u Pulse: 110 -160 bpm. Assess apically for 30 sec. 180 if crying 100 if sleeping u Temp: Rectal: 36. 6 – 37. 2 C 97. 8 - 99 F Axillary: 36. 5 – 37. 0 C 97. 7 – 98. 6 F If axillary temp is <36. 5 C, you recheck the other axilla. If it remains low, take babe out and do ‘skin-to-skin’ or double-wrap infant with hat on and recheck temp in 1 hour. If still low, place child in radiant warmer for 30 minutes and recheck temp. Temp rechecks can be done axillary. u Respirations: 30 -60/min. Assess for 1 full minute.

Newborns & Heat Loss u Factors that predispose a newborn to heat loss u Large surface area (especially head!) u Limited ability to control their metabolic rate u Blood vessels of the newborn are closer to the skin than adults u Decreased insulation due to less fat u It is essential to maintain a neutral thermal environment (NTE) to minimize O 2 consumption. u NTE range for naked newborn~ 32 -34 C (89. 6 -93. 2 F) u NTE range for adults~ 26 -28 C (78. 8 -82. 4 F)

Temperature Decrease (Hypothermia) Anaerobic Glycolysis p. O 2 and p. H Respiratory Rate Pulmonary Vasoconstriction

Heat Production u Vasomotor control—constriction of peripheral vessels manifested as acrocyanosis u ”Non-shivering thermogenesis”– primarily occurs through “brown fat” metabolism. Brown fat cells are larger than white fat cells & are easily broken down to produce heat.

Heat Production (cont’d) u Shivering- late sign of hypothermia. Indicates that metabolic rate has doubled, increased O 2 consumption, increased motor activity that ultimately leads to heat production u Insulation- 11 -17% of total body wt. of term neonates. Appears after 32 weeks gestation.

Heat Loss u evaporation - water to vapor u radiation - body to cold object u conduction - direct skin contact u convection - body to cooler air

GOAL: Keep baby in a neutral thermal environment: where the baby's metabolic rate, and therefore O 2 consumption, is minimal, but the body temperature remains within the normal range.

The Liver: Hepatic Functions u. Conjugates bilirubin u. Stores fetal iron u. Stores liver glycogen for energy ucoagulation

Physiologic Jaundice u Why does this happen? u immature liver cannot conjugate bilirubin u increased breakdown of RBC’s (normal Hct - 55%, RBC's = 5 -7 million/ul, Hgb = 15 -20 g/dl) u decreased clearance of bilirubin by liver due to inhibition of glucuronyl transferase = less conjugated bilirubin u reabsorption of bilirubin stuck in the intestines u obstruction or delayed meconium u hypoxia/CHD raise bilirubin levels u infection delays bilirubin excretion

u Common symptoms of jaundice u Yellowish tinge to skin or sclera of eyes u Test by blanching skin on bony prominence as forehead, or sternum

Treatment of Physiologic Jaundice u Phototherapy – Bililights overhead in hospital setting Quartz high intensity lights in hospital Wallaby blanket wrapped around infant at home u Frequent feedings to expel meconium more quickly from intestines

Coagulation & Vitamin K u The absence of normal flora in newborn gut needed to synthesize Vitamin K results in low Vitamin K levels until 5 th day of life u every newborn gets injected with Vit. K (AQUA MEPHYTON or PHYTONADIONE) to prevent bleeding problems.

Coagulation & Vitamin K u Dose: u 1 mg (0. 5 ml) IM >1500 gm u 0. 5 mg(0. 25 ml)IM<1500 gm

GI Adaptation - COOL facts. . . u BEFORE BIRTH, baby has already swallowed and peristalsis begins u stomach holds 50 -60 ml (2 ounces) u GI tract mature 36 -38 wks gestation u By 24 hours, the intestines are air filled u Saliva is hardly produced until 3 months u Babies regurgitate due to immature sphincter u Newborns lose 5 -10% body wt. in 5 -10 day u insensible water loss & low caloric intake

POOP! u. Meconium u. Transitional u. Fecal u. Breastfed

Urinary Adaption u Kidneys mature by 35 wks gestation u Limited ability to dispose of excess fluid u Most void immediately after birth u First 2 days: 2 -6 times/day u After that: 5 -25 times/day!!!!

Cool facts. . . u first void is cloudy due to mucous u “brick dust” urine- noted in diaper from urates (uric acid crystals)— may indicate dehydration u Pseudomenstruation = Vaginal discharge noted as blood in diaper

Neuromuscular Status Examples of neonatal reflexes

Reactivity States in the Newborn u. First period of reactivity - first 40 min. Baby is alert, responsive, eager to explore the world u Sleep period - 1 -3 hours after birth. May continue for 3 -6 hrs. Baby is in a deep sleep, difficult to arouse. Resp. rate & heart rate decrease. u Second period of reactivity – 3 -6 hours after birth. Baby is awake, respirations are rapid, irregular, and may have periods of apnea. May cough and regurg mucus, etc. Keep bulb syringe handy. Heart rate again increases.

Brazelton’s NBAS Each baby is born with their own traits and personality. This scale helps parents identify and get to know what is special and unique about their newborn. Temperament 1. ) easy child 2. ) slow-to-warm-up child 3. ) difficult child

6 categories of the NBAS u. Habituation u. Variation u. Orientation u. Self-quieting u. Motor u. Social maturity behaviors Read about each of these in your OB text- Pp. 749 -750. Link from March of Dimes

Brazelton’s Infant State Chart u SLEEP states u Deep or quiet u Active REM-light u ALERT states u drowsy u quiet alert (wide awake) u active alert u crying Know the characteristics of these states and when is the BEST time for interaction with the neonate!! (Pp. 701 -2)

What to Teach Parents

Newborn Screening One little heel stick tests for. . . u Congenital hypothroidism u Galactosemia—what implications does a positive result have for breastfeeding moms? u Maple syrup urine disease-- u PKU – Phenylketonuria—why does baby have to be at least 24 hours old for this test? u Hemoglobinopathies u Sickle Cell Anemia u Thalessemia

u Homocysteinuria u Cystic Fibrosis (new screening) u Congenital Adrenal Hyperplasia u Biotidinase Deficiency u More info at this link

Newborn SAFETY u. Bathing your baby--video u. Positioning— “Back to Sleep” u. Car seat rules—from the AAP, here all the recommendations for car seats for parents. Remember that NO BABY leaves the nursery without being in a car seat. u. CPR instruction—Here is a review of infant CPR with a quick quiz, if you need a review! u. Immunization schedule— 2013 Schedule

Fetal Development in utero

Fetal Development Continuum

That’s it!! Aren’t babies a miracle? ?