week 8 Flashcards
what are the physiological adaptation of the newborn?
-Establishing and maintaining respirations
-Adjusting to circulatory changes
-Regulating temperature
in utero respirations
In utero the placenta acts as the organ of respiration for the fetus. Immediately after the birth baby has to immediately adapt to the extra uterine respiration.
Clamping the umbilical cord causes a rise in blood pressure (BP), which increases circulation and lung perfusion.
Establishing and maintaining respirations- chemical factors
-Activation of chemoreceptors in the carotid arteries and aorta due fetal hypoxia
-Contraction temporary decrease uterine blood flow and transplacental gas exchange-transient fetal hypoxia
-↓Po2 and ↑Pco2, ↓blood pH
-Stimulation of the respiratory centre
Establishing and maintaining respirations-thermal factors
-↓extrauterine environment
-stimulates receptors in the skin, resulting in stimulation of the respiratory centre in the medulla.
-Note: Cold stress may be important for initializing breathing, but prolonged exposure should be avoided
Establishing and maintaining respirations-Mechanical factors:
-Changes in intrathoracic pressure from compression of the chest during vaginal birth.
-Relieve of the pressure result in a negative intrathoracic pressure, which helps draw air into the lungs.
-Crying of baby
-increases the distribution of air in the lungs, promotes expansion of the alveoli.
-creates positive pressure which helps to keep the alveoli open.
Establishing and maintaining respirations-Sensory factors
-handling or drying the newborn, lights, sounds, and smells of the new environment can also be involved in stimulation of the respiratory centre.
-Pain associated with birth can also be a factor
Circulatory Adjustment - after birth
-Umbilical veintransport oxygenated
-Umbilical arteries transportdeoxygenated
-Ductus arteriosusis the connection between pulmonary artery and aorta-closes within 24-48 hours; permanent closure may take several weeks
-Foramen ovaleis a shunt between the right atrium and the left atrium
-Circulatory changes after birth
-Expansion of the lungs increases the baby’s blood pressure
-Resulting in a major decrease in the pulmonary pressures decreases the changes in pressure result in
-↓shunting of blood to the ductus arteriosus and closure of the ductus arteriosus
-↑ pressure in the left atrium of the heart and lower the pressure in the right atrium causing the foramen ovale to close.
-Failure may result in patent foramen ovale (hole in heart) and surgical repair is required
Thermoregulation
-Heat regulation is most critical to the newborn’s survival.
-Anatomical and physiological characteristics of newborns place them at risk for heat loss-hypothermia
-Larger body surface to body weight
-Less adipose tissue & fat in newborn
-Underdeveloped sweating and shivering mechanisms
-Blood vessels closer to skin surface – contribute to heat loss
-Environmental factors include the temperature and humidity of the air, flow and velocity of the air, and the temperature of surfaces in contact with and around the newborn.
-Goal of care is to maintain a neutral thermal environment in which heat balance is maintained.
-To allows the newborn to maintain a normal body temperature to minimize oxygen and glucose consumption.
-Axillary temp. – between 36.4 – 37.2°
Evaporation
-Loss of heat when water evaporates from the skin and respiratory tract
-heat loss is intensified by failing to completely dry after bathing
-Dry baby quickly and remove wet towels/blankets
Conduction
-Heat loss from the body surface to cooler surfaces in direct contact
-Prewarm incubator/radiant warmer to ensure warm mattress
-Cover x-ray plates and scales
-Prewarm hands, stethoscopes, blankets and other equipment
-weighing the newborn should have a protective cover to minimize conductive heat loss
-Skin to skin contact: Baby will gain heat if placed on warm surface
Skin-to-skin keep newborns warmer than swaddled
Radiation
-Heat lost to surrounding colder solid objects (not in direct contact) but in close proximity
-Keep incubator, warmer, examination table, crib cot away from outside walls and windows
-Dress baby
-Care providers need to avoid exposing the newborn to direct air drafts.
Convection
-Heat lost from the body surface to cooler ambient air
-Raise surrounding 22° and 26°C
-Cover baby’s head
-Wrap and dress baby
-Warm O2
cold stress on baby
Effects of cold stress. When a newborn is stressed by cold, oxygen consumption increases and pulmonary and peripheral vasoconstriction occur, thereby decreasing oxygen uptake by the lungs and oxygen to the tissues; anaerobic glycolysis increases; and there is a decrease in Po2and pH, leading to metabolic acidosis.
-oxygen consumption and energy are diverted from maintaining normal brain and cardiac function and growth to thermogenesis for survival
-decreased pulmonary perfusion and oxygen tension can maintain or reopen the right-to-left shunt across the ductus arteriosus.
-cold stress is protracted, anaerobic glycolysis occurs, resulting in increased production of acids.
Transition to Extra Uterine Life- 1st period of reactivity
-Lasts up to 30 minutes after birth
-Newborn’s heart rate increases to 160 to 180 beats/min
-Respirations irregular: 60 to 80 breaths/min
-Decrease in motor activity after first period
-Period of decreased responsiveness
-Lasts 60 to 100 minutes
Transition to Extra Uterine Life- second period of reactivity
-Occurs 2 to 8 hours after birth
-Lasts 10 minutes to several hours
-Tachycardia, tachypnea occur
-Meconium commonly passed
-Increased muscle tone, changes in skin colour, and mucus production
Immediate Newborn Assessment-Apgar Scoring
-Immediate assessment of the newborn done at 1 and 5 minutes after birth
-Scores of 0 to 3-indicate severe distress,
-Scores of 4 to 6 indicate moderate difficulty
-Scores of 7 to 10 indicate that the newborn is having minimal or no difficulty adjusting to extrauterine life
-Reassessment is at 10 and 20 minutes if the score is less than 7 at 5 minutes
-Resuscitation may occur at any point when the newborn is compromised and should not wait until the initial 1-minute Apgar score
what does APGAR scoring stand for?
a-appearance
p-pulse
g-grimace
a-activity
r-respiration
Respiratory System -assessment
-Respirations
-Observe rise/fall of chest for 1 full minute
-Auscultate lung sounds
-Normal – 30-60 bpm,
-shallow & irregular;
-apneic periods of 5-10 seconds as fluid is being –absorbed/expelled
-Possible crackles - 1st hr. after birth
-Acrocyanosis – normal finding during transition
-Look for signs of respiratory distress
-Chest retractions
-Grunting with expirations
-Increase use of the intercostals muscles
-Nasal flaring
-Respiratory rate < 30 or > 60 breaths/min should be reported
Cardiovascular system-assessment
-heart rate between 110 and 160 beats/min
-Heart rate <110 or >160 re-evaluate after 30 t0 1 hour
-Heart murmurs heard during the first few weeks have -no pathologic significance
-murmurs disappear by 6 months
-Average systolic BP is 60 to 80mm Hg, and average diastolic BP is 40 to 50mm Hg
-Fetal Hb – high affinity for oxygen to promote oxygenation while infant begins producing own Hb postnatally
-Hb level 14-24 g/dl
-Blood volume 300mls
-Time taken to clamp cord
Sign of Cardiovascular concern
-Persistent tachycardia (more than 160 bpm)
-anemia, hypovolemia, hyperthermia, or sepsis.
-Persistent bradycardia (less than 100 bpm) congenital heart block, hypoxemia, normal sinus bradycardia, or hypothermia.
-Unequal or absent pulses, bounding pulses, and decreased or elevated blood pressure can indicate cardiovascular concerns
body measurement -weight
-Female: 3 400g
-Male: 3 500g
-Acceptable weight loss: 10% or less in first 3–5 days
-Regaining of birth weight within first 2weeks
-Weight ≤2 500g (preterm, small for gestational age, rubella syndrome)
-Weight ≥4 000g (large for gestational age, maternal diabetes, heredity—normal for these parents)
-Weight loss 10–15% (growth failure, dehydration); assess breastfeeding
Body Measurement-length
-45–55cm
<45cm or >55cm may be due to chromosomal abnormality or heredity—normal for these parents
Head circumference
– distance around head –
-33–35cm
-Circumference of head and chest approximately the same for first 1 or 2 days after birth
< 32 –microcepahly
-Microcephaly: head ≤32cm (maternal rubella, toxoplasmosis, cytomegalovirus, Zika virus, fused cranial sutures
[craniosynostosis])
-Hydrocephaly: sutures widely separated, circumference ≥4cm more than chest circumference
-infection
-Increased intracranial pressure (hemorrhage, space-occupying lesion) due
to extra fluid or extra tissue (tumour etc.)
Fontanelles
-Anterior fontanel 5-cm diamond, increasing as moulding resolves
-Closes within 12-18 months
-Posterior fontanel triangle 0.5x1 cm, smaller
than anterior
-Closes within 8-12 weeks after birth
