6. Asphyxia Neonatrum. pdf

Neonatology

1. ASPHYXIA NEONATRUM
By: Temesgen D (MSc)
12/27/2023 1

2. At the end of the session you will be able to:
•Define asphyxia neonatrum
•Discuss the etiopathologyof Asphyxia
•Describe pathophysiology of Asphyxia neonatrum
•Describe the clinical features of asphyxia neonatrum
•Discuss how to diagnose and treat asphyxia neonatrum
•Manage neonate with asphyxia neonatrum
Session Objectives
12/27/2023 2

3. Definition
WorldHealthOrganization(WHO)definesbirthasphyxiaasfailureto
initiateandsustainbreathingatbirth
Itcanalsobedefinedasplacentalorpulmonarygasexchange
impairmentleadingtohypoxemiaandhypercarbia
12/27/2023 3

4. Perinatal Asphyxia…
•As a result of anaerobic glycolysis lactate is produced and will
accumulate in the brain, heart and other tissues with a resultant effect
of metabolic acidosis (evidenced by low cord PH< 7).
•Manifestations of perinatal asphyxia are low APGAR score <3 at 10
th
minute and abnormal muscle tone
12/27/2023 4

5. Perinatal Asphyxia
Theessentialcharacteristicsforthediagnosisofperinatalasphyxiaare:
I.Profoundacidemia(pH<7.0)onumbilicalcordarterialbloodsample;
II.PersistenceofanAPGARscore0–3for>5min;
III.Neurologicalmanifestations(Hypotonia,Coma,Seizures)inthe
immediateneonatalperiod;
IV.Evidenceofmultiorgansystemdysfunction
12/27/2023 5

6. Perinatal Asphyxia…
Perinatal asphyxia is often the continuation of antepartum or
intrapartum event
It is a significant cause of perinatal death (50%).
Incidence of asphyxia varies depending on the gestational age
12/27/2023 6

7. Etiopathology of Perinatal Asphyxia
•Ninetypercent(90%)ofasphyxialeventsoccurintheantepartumor
intrapartumperiodsasaresultofplacentalinsufficiency.
•Therestsarepostnatal
•Asphyxiacanbeclassifiedbroadlyintothefollowinggroups:
A.Continuationofintrauterinehypoxia(placentalinsufficiency)
B.Prenatalandintranatalmedicationtothemother
C.Birthtraumatotheneonate
D.Postnatalfactors
12/27/2023 7

8. Placental insufficiency
The placenta, as a respiratory organ of the fetus, fails functionally
either due to anatomical changes or due to inadequacy of utero-
placental circulation such as:
Premature placental separation
Hypertensive disorders in pregnancy
Cord compression
Vascular anomalies in cord, etc.).
A. Continuation of Intrauterine Hypoxia
812/27/2023

9. Maternal hypoxic states:
The maternal diseases such as:
•Anemia
•Eclampsia
•Cyanotic cardiovascular disorders
•Status asthmaticus
•Dehydration and
•Hypotension
A. Continuation of Intrauterine Hypoxia…
912/27/2023

10. B. Prenatal and IntranatalMedication to the Mother
Morphine, pethidine and anaestheticagents depress the respiratory
centers directly and the chance of development of asphyxia is
increased.
12/27/2023 10

11. C. Birth Trauma to the Neonate
Malpresentation such as breech, oblique lie, occipitoposterioroften
requires manipulative and operative vaginal delivery (forceps or
ventouse).
Prolonged second stage of labor in contracted pelvis, often causes
asphyxia
Increased intracranial tension → cerebral edema and congestion →
increased intracranial pressure → asphyxia.
12/27/2023 11

12. D. Postnatal factors
Postnatalasphyxiaissecondarytopulmonary,cardiovascularand
neurologicalabnormalitiesoftheneonate.
Theseoftenoverlap,makingisolationofasinglecausativefactor
difficult
12/27/2023 12

13. Clinical Features
•The clinical features depend upon:
Etiology
Intensity and duration of oxygen lack,
Plasma carbon dioxide excess and
Subsequent acidosis
12/27/2023 13

14. Clinical Features…
•Theclinicalpictureisvitiatedbycoincidentalfetalshockduetobirth
trauma.
•Accordingtotheintensityofclinicalfeaturestheyhavebeenclassified
previouslyas:
a.Asphyxialivida(stageofcyanosis)and
b.Asphyxiapallida(stageofshock).
12/27/2023 14

15. APGAR score VsClinical features
•The APGAR score is related to the status of oxygenation of the fetus at or
immediately after birth.
•Long-term neurological correlation is obtained at the 5 minute score which is
of more value.
•In cases where the score remains significantly depressed at 5 minutes, it
should be evaluated again after 15 minutes.
12/27/2023 15

16. Newborn Arterial Blood Gases (Normal Value)
•Normal range of arterial blood gas values for a term newborn are :
Pa O2 50–80 (mm Hg);
Pa CO2 35–45 mm Hg;
HCO3 24–26 mEq/L and
pH 7.35-7.45
12/27/2023 16

17. Pathophysiology of Birth Asphyxia
•Initial response is hyperapneaand hypertension →Primary apnea →
Gasping attempt to breathe →(if unresolved) →Secondary apnea →
Bradycardia and Shock →Diminished cerebral blood flow → Cerebral
hemorrhage →hypoxic ischemic encephalopathy (HIE) →(if severe)
→ either death or disability (if the baby survives).
12/27/2023 17

18. Management
•Management of perinatal asphyxia can be divided into two:
1.Prophylactic
2.Definitive
12/27/2023 18

19. 1. Prophylactic
a)Antenatal detection of high-risk patients;
b)Thorough fetal monitoring to ensure early detection of fetal distress and
timely delivery;
c)Intrapartum use of electronic fetal monitoring and scalp blood pH
assessment when indicated. Scalp blood pH < 7.0 is a substantial
evidence of prolonged intrauterine asphyxia;
d)Cautious administration of anesthetic agents and sedatives during labor;
e)Cooperation between obstetric and pediatric staff since delivery;
f)Avoidance of difficult or traumatic delivery
12/27/2023 19

20. Definitive Management
•Active Resuscitation
12/27/2023 20

21. •HIE is a type of brain dysfunction that occurs when the brain
doesn't receive enough oxygen or blood flow for a period of time.
•HIE refers to the characteristic neurological manifestationsin
newborns which develop soon after birth following perinatal asphyxia.
Hypoxic Ischemic Encephalopathy (HIE)
12/27/2023 21

22. Classification of HIE
ClinicalspectrumsofHIEincludesmild,moderateorsevereaccordingtoSaranatstagesofHIE
12/27/2023 22

23. Before Birth: Sign of fetal distress
•Fetal heart rate changes
•Meconium stained amniotic fluid
•Fetal acidosis : scalp blood pH < 7.2
•Weak cord pulsation, if cord is prolapsed.
After Birth:
Clinical Features
APGAR score
Diagnosisof Asphyxia
2312/27/2023

24. Differential Diagnosis
Brain tumors
Developmental defects
Genetics of Methylmalonicacidemia
Genetics of Propionic acidemia
Infections
Neuromuscular disorders including neonatal myopathy
12/27/2023 24

25. Renal–acute cortical necrosis, renal failure
•Cardiovascular–hypotension, cardiac failure
•Liverfunction–compromised
•Gastrointestinal–ulcers and necrotisingenterocolitis
•Lungs–persistent pulmonary hypertension
•Brain–cerebral edema, seizures.
Complications
2512/27/2023

26. •Drugs are needed for a persistent HR < 60bpm even after ventilation and
chest compression.
•Epinephrine: 10 mg /kg ( 0.1 ml/kg of 1:10,000 solution) is given IV
when there is persistent bradycardia.
•It may be repeated every 5 minutes.
•Maximum dose is 30 mg/kg IV
•Sodium bicarbonate to treat metabolic acidosis (pH < 7.2) IV (4 ml/kg
of 0.5mEq/ml, 4.2% solution) is given.
Drugs used for Asphyxia (Resuscitation)
2612/27/2023

27. •Reversal of narcotic drug is needed when mother has been given Pethidineor
Morphinewithin three hours of delivery.
•Naloxone100 mg/kg is given to the baby by IV, IM or endotracheal.
•Volume expansion is needed when blood pressure is low and tissue perfusion is
poor.
•Normal saline, whole blood, 5% albumin or packed red blood cells (10 ml/ kg) IV
is given.
•Antibiotics: to guard against pneumonia which is liable to develop after prolonged
resuscitation.
Drugs used in Resuscitation
2712/27/2023

28. 12/27/2023 28