Neonatal asphyxia and resuscitation 2024.ppt

Asphyxia

1. Neonatal asphyxia
and resuscitation

2. Lungs and respiration
Physiology

3. Before birth
•Gas exchange in placenta
•Lung receives very little blood
•Alveoli are fluid filled

4. Alveoli are fluid filled
Blood vessels are
constricted

5. Before birth
•Pulmonary
arterioles are
constricted
•Umbilical arteries
feeding low pressure
placenta circulation
•Low pressure in
systemic circuit
•Very little
pulmonary blood
flow
•High pressure in
pulmonary circuit

6. After birth
•Fluid in the alveoli is
absorbed
Alveoli
• EXPAND
• GET FILLED WITH AIR (O
2)
1.

7. After birth
Umbilical arteries
and veins are
clamped
Sudden increase in
systemic blood
pressure
2.

8. Pulmonary vessels dilate, causing
increased blood flow to lungs
3.

9. PSC
PO
2
PPC
Circulation after
birth
Closed
foramen
ovale
Umbilical cord is
clamped
© K. Karlsen
2006
PO
2
50
-
100 mm
Hg

10. After birth
•Pulmonary
arterioles dilate
•Umbilical arteries
and veins are
clamped
•High pressure in
systemic circuit
•Dramatic increase
in pulmonary blood
flow
•Low pressure in
pulmonary circuit

11. Ductus arteriosus constricts
•Increased oxygen in blood
•Increased pulmonary blood flow
4.

12. Before After

13. Physiology of
Asphyxia

14. Asphyxia
is characterized by progressive
Changes in the pO
2, pCO
2, pH and base deficit of the umbilical arterial blood
of a term monkey fetus during a 12.5 minute episode of total asphyxia.

15. When an infant is deprived of oxygen,
an initial brief period of rapid
breathing occurs.
If the asphyxia continues, the
respiratory movements cease, the
heart rate begins to fall,
neuromuscular tone gradually
diminishes, and the infant enters a
period of apnea known as primary
apnea.
Types of Apnea

16. Primary apnea
•Rapid breathing
•Respiratory standstill
•Heart rate begins to fall
•Normal blood pressure
•Good response to tactile stimulation

17. Types of Apnea
If the asphyxia continues, the infant
develops deep gasping respiration,
the heart rate continues to decrease,
the blood pressure begins to fall, and
the infant becomes nearly flaccid. The
respirations become weaker and
weaker until the infant takes a last
gasp and enters a period of
secondary apnea.

18. Secondary apnea
•Irregular breathing
•Heart rate continues to decrease
•Blood pressure begins to fall
•Unresponsive to tactile stimulation

19. Apnea has been classified into three types
depending on whether inspiratory muscle
activity is present.
If inspiratory muscle activity fails following
an exhalation, it is termed Central Apnea.
If inspiratory muscle activity is present
without airflow, this is termed Obstructive
Apnea.
If both central and obstructive apnea occur
during the same episode, this is termed
Mixed Apnea.
Types of Apnea

20. Changes due to oxygen
deprivation

21. Remember!
Fetal hypoxia may lead to apnea at
birth!
It implies that when faced with an
apneic infant at birth, assume that
you are dealing with secondary
apneaand be ready to undertake
full resuscitation efficiently.

22. Pulmonary circulation and
asphyxia
An asphyxiated infant has hypoxemia and
acidosis.
In the presence of hypoxemia and acidosis, the
pulmonary arterioles remain constricted and
ductus arteriosus remains open.This results in
persistence of fetal circulation. As long as
decreased pulmonary perfusion exists, proper
oxygenation of the tissues of the body is
impossible, even when the infant is being
properly ventilated.

23. Cardiac function and
systemic circulation

24. Results of decreased O
2
in the fetal blood
O
2in coronary
blood flow
Ventricular
contractility
Hypoxic
myocardial injury
Coronary
blood flow
Blood
pressure
Cardiac
output
Blood flow
to brain
Intracranial
pressure
Cerebral
edema
O
2to
brain
Hypoxic
injury of brain

25. Common Causes of Partial Asphyxia of the Fetus
1.Excessive oxytocin
2.Maternal hypotension
3.Placental abnormalities
Common Causes of partial
asphyxia

26. RISK FACTORS OR
CONTRIBUTING FACTORS

27. RISK FACTORS OR
CONTRIBUTING FACTORS
1.Maternal Disease (renal, pulmonary,
diabetes, etc.
2.Maternal Drugs (Mg
++
, narcotics)
3.History of Perinatal Disease or Death
4.Inadequate Prenatal Care
5.Surgery During Pregnancy
6.Abruption, Placenta Previa
7.Pre-Eclampsia, Eclampsia,
Hypertension
MATERNAL FACTORS

28. INTRAPARTUM FACTORS
1.Cephalopelvic disproportion
2.Sedatives/Analgesics
3.Prolonged labor
4.Precipitous labor
5.Difficult delivery
6.Maternal hypotension
7.Cord compression or prolapse
8.C-section
9.Abnormal presentations (breech, etc.)
10.Forceps
INTRAPARTUM

29. FETAL FACTORS
1.Multiple births
2.Polyhydramnios
3.Oligohydramnios
4.Immature L/S Ratio
5.Premature/Postmature
6.Large or Small for Gestational Age
7.Meconium Stained Amniotic Fluid
8.Abnormal Heart Rate or Rhythm
9.Fetal Acidosis
FETAL RISK FACTORS

30. 1.To assist the infant in establishing adequate
oxygenation, ventilation, pulmonary perfusion,
and cardiac output.
2.To maintain adequate peripheral circulation.
3.To minimize body heat loss.
4.To provide an adequate supply of glucose.
5.To correct acid-base and electrolyte
disturbances.
BASIC GOALS

31. Apgar score
Sign 0 1 2
Heart Rate Absent <100 >100
Respirations Absent
Slow
irregular
Good
crying
Muscle Tone Limp
Some
flexion
Active motion
Reflex Irritability
No
response
Grimace Cough, cry
Color Blue or pale
Body pink,
extremities
blue
Completely

32. Apgar score is great, but not
for guiding resuscitation
•For resuscitation, not all items are
required
•Resuscitation initiated before 1 min
when Apgar is assigned
•Classification different

33. •When 5 min APGAR score is <7,
evaluate APGAR every 5 min up to 20
min or until it improves >8
Apgar score is useful in
assessing the resucitative effort

34. DIFFERENTIAL DIAGNOSIS OF “LOW APGAR”
SCORE
•Baby is not crying
•Blue color
•Low muscle tone
Indicaton for neonatal
resuscitation

35. Be ready to resuscitation

36. Team work

37. Timing of umbilical cord
clamping
•DCC for 30-60 s is reasonable for both
term and preterm infants who do not
require resuscitation at birth.

38. Timing of CC for non-vigorous
babies
•Research on resuscitation with intact
cord ongoing
•• If PPV required, cord should be cut and
infant transferred to overbed warmer for
•resuscitation

39. Neonatal resuscitation
•Airway
•Breathing
•Circulation

41. Ventilation

42. Position of the baby

43. Circulatory support
•30 seconds PPV via AA
•CC if HR < 60. 3:1 ratioand 100% FiO2
•If no ↑HR: “CARDIO
•If HR < 60 after 60 secs
•CC→ epinephrine

44. Epinephrine dosing
•• IV or IO = 0.02 mg/kg (equal to 0.2 mL/kg)
•• May repeat every 3 to 5 minutes
•• Range = 0.01 to 0.03 mg/kg (equal to 0.1 to
0.3mL/kg)
•• Endotracheal = 0.1 mg/kg ( equal to 1 mL/kg)
•• Range = 0.05 to 0.1 mg/kg (0.5 to 1 mL/kg)
•• Flush: Follow IV or IO dose with a 3-mL
saline flush(previous 0.5-1ml)

45. Medication
•Epinephrine IV/IO dose range 0.01-0.03mg/kg
•• Suggested initial IV/IO =0.02mg/kg.
•Suggested initial ET dose =0.1mg/kg
•• Flush with 3 ml normal saline
•• Can rpt every 3-5 mins: “consider ↑subsequent
•doses”
•

46. If the HR no
•After 3-5min epinephrine
•Consider hypovolemia
•Consider pneumothorax

47. Outcomes of newborn infants who
received ≥ 20 min of CPR after birth
•Only 39 infants in whom first detectable HR or
HR >100/min occurred at or beyond 20
minutes after birth.
•15/39 (38%) survived until last follow-up
•6/15 (40%) of survivors did not have NDI
Wyckoff M et al. Circulation, 2020;142(Supp): S185-S221

48. Evaluation: By 3 signs
1.Respiration
•Breathing / crying
•Apnea
2.Heart rate
•<100 or not
•< 60 or not
3.Color
•Central cyanosis
•Peripheral cyanosis / pink

49. Post Resuscitation Period
1.Neuro-thermal Environment
2.Gradually Discontinue Oxygen
3.Maintenance Fluids
4.Monitor Vital Signs (including B.P.)
5.Monitor Hematocrit and Dextrostix
6.May Require Assisted Ventilation
7.Delay Feedings; Then Begin Cautiously
8.Chest x-ray

50. Timing for discontinuation
•Reasonable time frame for considering
cessation of resuscitation effort is around 20
minutes after birth
•It should be individualized based on patient
and contextual factor:
–Optimal resuscitation
–Availability of advanced NICU care
–Specific circumstances before delivery
–Wishes expressed by the family

51. Cessation of resuscitation
•It is appropriate to consider discontinuing after
effective resuscitation efforts if:
•• Infant is not breathing and heartbeat is not
detectable beyond 10 min, stop resuscitation.
•• If no spontaneous breathing and heart rate
remains below 60/min after 20 min of effective
resuscitation, discontinue active resuscitation.
Record the event and explain to the mother or
parents that the infant has died.
•Give them the infant to hold if they so wish