Asphyxia neonatorum

 

INTRODUCTION

 

          Marked homeostatic changes occur during the transition from fetal to newborn life.  The most rapid anatomic and physiologic changes of this period occur in the cardiopulmonary system.  Thus the major problems of the newborn are usually related to this system.  These include asphyxia, respiratory distress syndrome, cord stress, jaundice, etc.

DEFINITION

          Asphyxia neonatorum is defined failure to initiate and maintain spontaneous respiration within one minute of birth.

 

INCIDENCE

          Incidence of birth asphyxia is 5-10%.

 

ETIOLOGY

          The etiology of asphyxia can be classified broadly into following groups.

A.   Continuation of intrauterine hypoxia

v The placenta, as a respiratory organ of the fetus fails functionally either due to anatomical changes in the placenta or due to inadequacy of utero-placental circulation.

v  Maternal hypoxic states

Ø  Anemia

Ø  Eclampsia

Ø  Cyanotic cardiovascular disorders

Ø  Status asthmatics

Ø  Dehydration

Ø  Hypotension

Ø  Shock   

B.   Birth trauma to the neonate

a)      Malpresentation such as breech, oblique lie, occipital-posterior.

b)      Prolonged second stage of labour in contracted pelvis. 

C.  Medications

Morphine

Pethidine

Anesthetic agents 

D.  Post natal

Postnatal asphyxia is secondary to pulmonary, cardiovascular, and neurological abnormalities of the neonate.  

Factors which are affecting the asphyxiva

1.   Factors affecting the upper respiratory tract.

a)   Aspiration of amniotic fluid, blood or meconeum.

b)   Congenital malformations

2.   Factors affecting the lung.

a)   Premature lung which fails to expand.

b)   Congenital absence of lung or collapse due to pneumothorax.

3.   Factors affecting the thoracic cage

a)   Prematurity causing indrawing of intercoastal drainage

b)   Trauma to the ribcage during vigorous attempts at resuscitation.

4.   Miscellaneous

a)   Congenital cardiac lesions causing cyanotic heart disease.

b)   Anomalous vascular connections.

 

Clinical Sequence of birth asphyxia

Initial responses in hyperpnoea and hypertension

ß

Primary apnoea

ß

Gasping attempt to breathe

ß

Bradycardia and shock

ß

Diminished cerebral blood flow

ß

Cerebral hemorrhage

ß

Hypoxic ischemic encephalopathy (if severe)

ß

Either death or handicap (if baby survives)

 

 

 

CLINICAL FEATURES

 

          Clinical features depend upon the etiology, intensity and duration of oxygen lack, plasma carbon dioxide excess and subsequent acidosis.

 

          According to intensity of clinical features they have been classified as asphyxia livida and asphyxia pallida.

 

a.    The baby fails to establish respiratory and cry.

b.    The colour become pale.

c.    The baby appears limb.

d.    The heart rate becomes slow and irregular.

e.    The apgar score is low, below 4.

 

 

MANAGEMENT

MEDICAL MANAGEMENT

Management of  perinatal asphyxia can be divided into two

·        Prophylactic

·        Definitive

a) Prophylactic management

·        Antenatal detection of high risk patients.

·        Scrupulous fetal monitoring particularly in high risk pregnancy.

·        Intrapartum use of fetal monitoring and scalp blood pH assessment when indicated.

·        Judicious administration of anesthetic agents and sedatives during labour.

 B) Definitive Management

·        Endotracheal intubation and intermitted positive pressure ventilation must be started immediately.

·        Aspiration done through the endotracheal tube.

·        Gentle external cardiac massage is performed if the heart rate is below 60/mt.

 

Pharmacological management

·        8.4% of sodium bicarbonate 1meq / kg in 5% dextrose is given through the umbilical or peripheral vein very slowly.

·        Adrenaline 0.1-3ml is injected through umbilical vein

·        Calcium chloride 20-30mg is injected to improve output.

·        If mother has received pethidene or morphine with in 3 hours of labour/ delivery, halaxone is given IV to the neonate.

 

NURSING MANAGEMENT

 

a)     Assist the mother for scrupulous fetal monitoring in high risk pregnancy.

b)     Nurse must give the enough psychological support to the mother.

c)     If any manifestations of fetal distress is evident inform to the doctor immediately.

 

After the birth of the baby

a.      Cord should clamped and cut only after the pulsation is stopped.

b.     Hold the baby in a head down position to facilitate drainage of the mucus and other secretions.

c.      Baby should be kept under a radiant warmer.

d.     Baby Oropharynx and nasopharynx are thoroughly cleared for mucous by using a mucous sucker.

e.      Mope the baby thoroughly.

f.       If the baby is not crying soon after birth, pattered the baby’s feet and rubbed the back to make the baby cry.

g.      To note the well being of the baby, apgar scoring should be monitored.

h.     Check the weight of the baby and anthropometric measures should be taken.

i.       Depending upon the degrees of respiratory distress, start oxygen supply.

 

Baby with Apgar Score 7-10

·        The oropharynx and nasopharynx are to be cleared off any mucous by suction.

·        O₂ is administered when required only.

·        The condition is reassured at 5 minutes and if found normal, the infant should given at mother.

Babies with apgar score 4-6

·        Baby may follow primary apnoea.

·        Place under a radiant heater, dry the baby.

·        The baby is put flat or slight head down position with the face on one side to facilitate gravitational drainage of fluid from the respiratory passage.

·        Stimulus to back and sole.

·        Simultaneously, oxygen (100%) is administered at a rate of 5L/min, by bag mask at a pressure range of 25-30 cm H₂O.

·        Intermittent positive ventilation is given if necessary

 

Babies with Score below 4

·        Tracheal intubation and intermittent positive pressure ventilation must be started immediately.

·        Monitor the degrees of respiratory distress and note the apgar scoring.

·        Check the patency of ventilator functioning.

·        Start a gentle mouth to mouth respiration.

·        Monitor the vital signs regularly.

·        Monitor / maintain the apgar scoring every 5 minutes.

COMPLICATIONS

A.  Immediate complications

a. Cardiovascular

Hypotension, cardiac failure

b. Renal

Acute cortical neurosis, renal failure

c. Liver functions

Compromised

d. Gastrointestinal

Ulcers and necrotizing entrocolitis

e. Lungs

Persistant pulmonary hypertension

f. Brain

Cerebral edema and seizures

B. Delayed Complications

a.  Retarded mental and physical growth

Epilepsy

Minimal brain dysfunction

CONCLUSION

 

          Asphyxia neonatorum is failure of efficient pulmonary respiration at birth with hypoxia.  If respiration is fails to establish 60 second, the neonate will be asphyxiated.  About 10% of the babies at birth shows varying degrees of asphyxia.  It is one of the common causes of neonatal mortality.  Asphyxia for more than seven minutes may cause irreversible damage or death.

BIBLIOGRAPHY

 

1.             D.C.DUTTA ‘Text Book of Gynaecology Including Contraception”, New Central Book Agency (LTD), Page N.469-473, Edition, 5^th.

2.             A.L.MUDALIAR, M.K.KRISHNA MENON, Muddaliar and Menon’s Clinical Obstetrics, Orient Longman Limited, Edition, Ninth, page.No.376-383.