Case 82 - neonatal resucictation Flashcards

1
Q

Describe the fetal circulation

A
  • gas exchange occurs at placenta
    • oxygenated blood - PaO2 of 30-35 mmHg
  • umbilical vein carries oxygenated blood from placenta to fetal circulation
  • the **oxygenated blood from placenta **​bypasses liver via ductus venosus and travel to RA –> PFO to LA
  • **deoxygenated blood **from SVC (drains head and neck) will be directed to RV –> PA –> ductus arterosis
  • blood in aorta will flow to tissues, become deoxygenated and flow back to placenta for gas exchange via **umbilical arteries (2 arteries)

High PVR, low SVR

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2
Q

What physiologic changes occur at birth?

A

1) Decrease PVR
* first breath -> lung expansion -> inc Alveolar PaO2
2) increase SVR
* clamping umbilical cord and removal of placenta (low-resistance system) results in inc SVR

Shunts

foramen ovale

  • inc SVR leads -> inc LV pressure -> inc LA pressure -> functional closure of foramen ovale

ductus arteriosus

  • inc PaO2 2/2 lung expansion and inc alveolar PaO2 leads to functional closure of ductus art
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3
Q

why is neonatal circulation sometimes referred to as transitional circulation?

A
  • once fetus is born, there circulatory system begins to resemble an adult circulation
  • functional closure takes time for complete closure
  • states that increase PVR will reverse the functional closure of shunts and make them patent:
    • ​hypoxemia, hypercarbia, acidosis, hypothermia, sympathetic stimulation,
    • persistent pulm HTN of newborn (RDS, congenital diaphragamtic hernia)
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4
Q

baby is born, initial APGAR is 2, what will you do?

A

Newborn resucitation

4 steps: initial steps, ventilation, chest compressions, admin of epi and volume expansion

1) Initial steps

Term gestation? breathing or crying? good tone?

  • Yes - routine care: provide warmth, clear airway if necessary, dry, continuous eval
  • No - warm, suction airway, dry, stimulate

2) Is HR < 100, gasping or apnea?

  • Yes - PPV and preductal SpO2 monitoring
  • No - supportive care (clear airway, CPAP?)

3) Is HR still < 100 or now < 60

  • HR 60-100 - continue PPV
  • HR < 60 - chest compressions, PPV, consider intubation

4) is HR still < 60

  • yes - IV epinephrine, consider hypovolemia or pneumothorax

Notes

  • PPV - 40 to 60 bpm
  • HR - check via stethoscope or palpation of umbilcal artery
  • intubation - consider in nonvigorous newborn with meconium staining, when chest compressions occur, ineffective bag mask ventilation, cong diaph hernia
  • epi dose - 1:10,000 0. 01 - 0.03 mg/kg IV
  • CPR - 3:1 ratio, or 1 minute = 90 compressions: 30 vent
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5
Q

What should be the oxygen administration during neonatal resucitation?

A
  • 100% FiO2 can be detemential in neonatal resucitation outcome.
  • initial oxygen concentration used may be air or blended oxygen, and oxygen concentration is titrated to target preducatal saturation for age
    • if HR is <60 bpm after 60 sec of adequate ventilation, then use 100% oxygen
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6
Q

How would you manage a neonate when meconium is present?

A
  • tracheal suctionioning still controversial
  • is neonate vigorous, breathing, crying, good tone?
    • yes, observe
    • no - tracheal suction and monitor HR
      • if there is persistent bradycardia, abort tracheal suction and go to neonatal resucitation protocol
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7
Q

what is APGAR score?

A
  • assessed at 1 and 5 minutes
  • APGAR = appearance (color), pulse, grimace, activity, respirations
  • one should NOT wait until 1 minute after birth to begin resuscitative efforts.
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