OB Exam 4
Chapter 17:
Mechanical stimulation
- Vaginal squeeze
o Squeezes chest: increase in intrathoracic pressure
Expels fluid; chest recoils after
o C-section babies don’t have squeeze because they still have extra fluid
Higher risk for transient tachypnea
Transient tachycardia- breath super fast for short period of time and then
back to normal
Chemical stimulation
–↓O2 ↑PCO2 ↓pH → Transitory Asphyxia
Transient asphyxia: a lack of blood flow or gas exchange to or from the fetus in
the period immediately before, during, or after birth
S/S: weak breathing, abnormal respirs, blueish skin, low HR, poor muscle tone,
weak reflexes, acidosis, meconium stained amniotic fluid
– Hypoxic, tachypneic, acidotic at birth (CO2 up)
– Triggers baby to take a breath
■ It all starts with one breath!
Sensory stimulation
- Thermal, pain, touch, light, sound, gravity
- They go from dark, warm, and quiet to bright, loud, and cold
Surfactant
- Produced at 25 weeks, but not enough until 37 weeks
o Preemies don’t have enough surfactant so they have a higher risk for respiratory distress
- Lubricant to prevent atelectasis
- Keeps alveoli open
- Provides tension for lung expansion and compliance
- Betamethasone to mom, surfactant to baby
- LS ratio: 2:1
o Determine by testing amnio fluid
o Need to know this ratio if preterm: determine if baby’s lungs are okay to expand
Neonatal respirations
- Rate 30-60 breaths per min
- Normal
o Abdomen and chest move in synch (belly breathers)
- Abnormal
o See-saw (bad)
- Short periods of apnea
o If 15s of no breathing go by, worry about cyanosis
o Keep nose clear! They can be belly and nose breathers
, - Shallow and irregular
- Decreased pressure in lungs> causes them to breathe
- Signs of respiratory distress
o Cyanosis
o Tachypnea
o Expiratory grunting
o Sternal retractions
o Nasal flaring
- Baby does not breathe until umbilical cord is clamped
Changes in fetal heart rate
- Fetal circulation > newborn circulation
- Apical for 1 min
- Can hear murmurs because these may not have closed yet
- Foramen ovale
o Hole between left and right atriums
o Closes 1-2 hours after birth
- Ductus arteriosus
o Pulmonary artery to aorta
o Closes 15 hours after birth
- Ductus venosus
o Goes into inferior vena cava from liver
o 3-7 days turn into a ligament
- Fetal circulation: ductus arteriosus (open), foramen ovale (open), ductus venosus
- Newborn circulation: ductus arteriosus (closed), foramen ovale (closed), ductus venosus
Blood volume and components
- Blood volume
o Depends on mom’s blood volume
o Depends on when cord is clamped
- Delayed cord clamping 30-40 seconds (some wait up till 3 min)
o Helps prevent iron-deficiency anemia and helps adjusting to circulation
o Can increase blood volume 25-40%
- Blood components
o Adult RBC 120 days
o Fetal RBC 80-100 days
Break down (die) faster
Larger
Carry more O2
More in babies than adults
o Liver not fully functioning, RBC die faster, cant conjugate quick enough = jaundice
Conjugating- fat sol > H2O sol (excreted in urine/stool)
o Leukocytosis (high WBC) form birth trauma
- Thermoregulation
o Normal body temp in newborn: 97.7-99.5 (36.5-37.5)
, o Balance b/t heat loss and production
o External environmental factors
o Internal physiologic process
o Need a neutral environment (NTE)
Def: environment in which body temp is maintained without an increase in
metabolic rate or oxygen use
Promotes growth and stability and conserves energy for basic body functions
- Newborns lose heat because:
o Thin skin, vessels close to the surface
o Can shiver; limited stores of glucose, glycogen, fat
o Limited use of voluntary muscles
o Large body surface area relative to body weight
o Lack of subQ fat; little ability to conserve heat by changing posture
o No ability to adjust clothing/ blankets
o Cannot communicate if their too cold
o At 2 degree drop= increased O2 requirements
Methods of heat loss
- Conduction
o Skin against cool surfaces
Cold stethoscope, cold hands, putting baby on cold scale; any contact cooler than
baby
Skin to skin helps prevent this
Warm up hands, warm stethoscope, put blankets on scale
- Convection
o Cool air blowing on you
AC and fans, drafts, doors open/ close, in heated isolate and then take baby out
Overheating
- Limited insulation
- Limited sweating ability
- Large body surface area
- Primary heat regulator located in hypothalamus
o Newborns CNS is immature
- Increase fluid loss, RR, and metabolic rate
Cold stress
- Excessive heat loss that requires a newborn to use compensatory mechanisms (nonshivering
thermogenesis- breaking down brown fat and tachypnea) to maintain core body temp
o As temp decreases, newborns become less active, lethargic, hypotonic, and weaker
o Metabolic acidosis
- Signs:
o Skin cool to touch/ mottling
o Central cyanosis
o Decreased responsiveness
o Jittery (low glucose)
o Tachypnea
Chapter 17:
Mechanical stimulation
- Vaginal squeeze
o Squeezes chest: increase in intrathoracic pressure
Expels fluid; chest recoils after
o C-section babies don’t have squeeze because they still have extra fluid
Higher risk for transient tachypnea
Transient tachycardia- breath super fast for short period of time and then
back to normal
Chemical stimulation
–↓O2 ↑PCO2 ↓pH → Transitory Asphyxia
Transient asphyxia: a lack of blood flow or gas exchange to or from the fetus in
the period immediately before, during, or after birth
S/S: weak breathing, abnormal respirs, blueish skin, low HR, poor muscle tone,
weak reflexes, acidosis, meconium stained amniotic fluid
– Hypoxic, tachypneic, acidotic at birth (CO2 up)
– Triggers baby to take a breath
■ It all starts with one breath!
Sensory stimulation
- Thermal, pain, touch, light, sound, gravity
- They go from dark, warm, and quiet to bright, loud, and cold
Surfactant
- Produced at 25 weeks, but not enough until 37 weeks
o Preemies don’t have enough surfactant so they have a higher risk for respiratory distress
- Lubricant to prevent atelectasis
- Keeps alveoli open
- Provides tension for lung expansion and compliance
- Betamethasone to mom, surfactant to baby
- LS ratio: 2:1
o Determine by testing amnio fluid
o Need to know this ratio if preterm: determine if baby’s lungs are okay to expand
Neonatal respirations
- Rate 30-60 breaths per min
- Normal
o Abdomen and chest move in synch (belly breathers)
- Abnormal
o See-saw (bad)
- Short periods of apnea
o If 15s of no breathing go by, worry about cyanosis
o Keep nose clear! They can be belly and nose breathers
, - Shallow and irregular
- Decreased pressure in lungs> causes them to breathe
- Signs of respiratory distress
o Cyanosis
o Tachypnea
o Expiratory grunting
o Sternal retractions
o Nasal flaring
- Baby does not breathe until umbilical cord is clamped
Changes in fetal heart rate
- Fetal circulation > newborn circulation
- Apical for 1 min
- Can hear murmurs because these may not have closed yet
- Foramen ovale
o Hole between left and right atriums
o Closes 1-2 hours after birth
- Ductus arteriosus
o Pulmonary artery to aorta
o Closes 15 hours after birth
- Ductus venosus
o Goes into inferior vena cava from liver
o 3-7 days turn into a ligament
- Fetal circulation: ductus arteriosus (open), foramen ovale (open), ductus venosus
- Newborn circulation: ductus arteriosus (closed), foramen ovale (closed), ductus venosus
Blood volume and components
- Blood volume
o Depends on mom’s blood volume
o Depends on when cord is clamped
- Delayed cord clamping 30-40 seconds (some wait up till 3 min)
o Helps prevent iron-deficiency anemia and helps adjusting to circulation
o Can increase blood volume 25-40%
- Blood components
o Adult RBC 120 days
o Fetal RBC 80-100 days
Break down (die) faster
Larger
Carry more O2
More in babies than adults
o Liver not fully functioning, RBC die faster, cant conjugate quick enough = jaundice
Conjugating- fat sol > H2O sol (excreted in urine/stool)
o Leukocytosis (high WBC) form birth trauma
- Thermoregulation
o Normal body temp in newborn: 97.7-99.5 (36.5-37.5)
, o Balance b/t heat loss and production
o External environmental factors
o Internal physiologic process
o Need a neutral environment (NTE)
Def: environment in which body temp is maintained without an increase in
metabolic rate or oxygen use
Promotes growth and stability and conserves energy for basic body functions
- Newborns lose heat because:
o Thin skin, vessels close to the surface
o Can shiver; limited stores of glucose, glycogen, fat
o Limited use of voluntary muscles
o Large body surface area relative to body weight
o Lack of subQ fat; little ability to conserve heat by changing posture
o No ability to adjust clothing/ blankets
o Cannot communicate if their too cold
o At 2 degree drop= increased O2 requirements
Methods of heat loss
- Conduction
o Skin against cool surfaces
Cold stethoscope, cold hands, putting baby on cold scale; any contact cooler than
baby
Skin to skin helps prevent this
Warm up hands, warm stethoscope, put blankets on scale
- Convection
o Cool air blowing on you
AC and fans, drafts, doors open/ close, in heated isolate and then take baby out
Overheating
- Limited insulation
- Limited sweating ability
- Large body surface area
- Primary heat regulator located in hypothalamus
o Newborns CNS is immature
- Increase fluid loss, RR, and metabolic rate
Cold stress
- Excessive heat loss that requires a newborn to use compensatory mechanisms (nonshivering
thermogenesis- breaking down brown fat and tachypnea) to maintain core body temp
o As temp decreases, newborns become less active, lethargic, hypotonic, and weaker
o Metabolic acidosis
- Signs:
o Skin cool to touch/ mottling
o Central cyanosis
o Decreased responsiveness
o Jittery (low glucose)
o Tachypnea
