Case 82 - neonatal resucictation Flashcards
Describe the fetal circulation
- 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
What physiologic changes occur at birth?
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
why is neonatal circulation sometimes referred to as transitional circulation?
- 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)
baby is born, initial APGAR is 2, what will you do?
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
What should be the oxygen administration during neonatal resucitation?
- 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
How would you manage a neonate when meconium is present?
- 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
what is APGAR score?
- 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.