perinatal asphyxia for level 5 mbchb p

8/13/2019 Perinatal Asphyxia for Level 5 Mbchb p

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PERINATAL

ASPHYXIA

Fred N WereDepartment of Paediatrics

University of Nairobi


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DEFINITION

A range of disorders that occur

subsequent to oxygen deprivation of a

fetus/newborn during the two weekssurrounding delivery

The main syndrome usually involves the

brain but many other organs can beinvolved


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Pathophysiology-Gross

Reduction of oxygen supply to the body

organs (HYPOXIA)

Progressive reduction of systemic bloodflow (ISCHEMIA)

Eventual decrease of cerebral & coronary

blood flow (LOSS OF AUTOREGULATION)

Hypoxic/Ischaemic cell death


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Pathophysiology-Molecular

Accumulation of intracellular calcium

Increase of excitatory amino acids in thedamaged cells

Elaboration and increased liberation of

reactive oxygen species (free radicals)


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Etiology

PrenatalPlacental insufficiency syndromes

Labor/Deliveryprolonged/obstructed laborcord accidents/ Ante partum hemorrhage

Post Natalineffective resuscitation at birthsevere respiratory diseases


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Clinical Diagnosis

APGAR SCORING

This signifies presence of Central

Nervous system depression

PRESENCE OF ENCEPHALOPATHYSuggesting actual neuronal damage


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APGAR SCORING

0 1 2

Appearance Pale/blue peripheral cyanosis pink

PULSE 0 100

Grimace None Weak Strong

Activity None Weak Strong

Respiration None Shallow LustyPerformed at 1&5 minutes. If abnormal repeated at 10 &

20 minutes


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APGAR Interpretation

1 minute score identifies those needing

resuscitation

5 minute score defines asphyxia as:

Mild 6&7

Moderate 4&5

Severe 0-3

Extended scores estimate or predict later

outcomes


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Hypoxic Ischaemic Encephalopathy

Grade 1; MILD

Hyperactive and jittery, no convulsions

Grade 2; MODERATE

dull and lethargic but awake or arousable

convulsions frequent

Grade 3; SEVEREStuporous/comatose with intractable fits

Other organ involvement, decorticate or decerebrate


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Laboratory Evaluation

Cerebral Ultrasound

Electro Encephalography

CT Scans

MRI


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Principals of Management

Effective resuscitation at birth

Active maintenance of normal homeostasis

during the acute phase

Appropriate management of convulsions and

other complications

Some experimental methods


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other complications



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Objectives Of Resuscitation

To correctly identify the need for

resuscitation at birth

To understand the ABC sequence of

resuscitation as applied to the newborn


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Evaluation of the Newborn

Dry and warm the newborn

The need for life support interventions willbe indicated by the simultaneous

evaluation of:

Respiration

Colour

Heart rate


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Respiration

Good spontaneous respiratory activity may manifest as

vigorous crying or adequate breaths

Dry warm and leave infant alone

If apnoea or gasping persist after a few seconds of tactile

stimulation:

ABC of resuscitation must commence


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Heart Rate

Observe HR at praecodium or base of umbilicus

If HR


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Colour

Central

cyanosis/palor

with adequatebreathing:

Deliver free flow

oxygen

No breathing:

ABC of resusc


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AIRWAY: Clearing

Position infant and

remove secretions

Neutral / slightlyextended position by

towel placement

Secretions clearedfirst from the mouth,

then from the nose


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BREATHING and Stimulation

Routine drying and

suctioning

Rubbing the back

Flicking the soles of thefeet

If no response to tactile

stimulation occurs within

few seconds:Then bag, valve and mask

ventilation with 21-100%

oxygen


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Positive Pressure Ventilation

Adequate expansion of the lung is the most important

measure needed for successful resuscitation

Indicationsfor IPPV:

Apnoea / gasping

breath

HR < 100 bpm

Persistent central

cyanosis


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Positive Pressure Ventilation

Most newborns who require positivepressure ventilation can be adequately

ventilated with a bag valve and mask


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Key Point:

The most important and effective

action in neonatal

resuscitation is:

Ventilation with Air or Oxygen


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Tracheal Intubation

Indications for tracheal intubation during neonatal

Resuscitation include: Tracheal suctioning

Ineffective / prolonged BVM

Chest compression required

Tracheal drugs

Congenital diaphragmatic

hernia

Extreme prematurity

Transport


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If the heart rate is < 60 bpm despiteeffective positive pressure ventilation with100%oxygen then give CC at ratio of 3 to 1

i e 90 cc for 30 breaths

Chest Compressions


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Emergency Drugs

Very rarely required

If HR < 60 bpm after 30 seconds of adequateventilationand chest compressions:

Adrenaline (10-30mcg/kg)

IV (peripheral/umbilical), Tracheal, Osseous

Newborn Life Support


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CCD

Newborn Life Support

Airway&

BreathingAB

CD

coverDry &

RC (UK)


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other complications



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Maintenance of Homeostasis Monitor and maintain oxygenation

Monitor and correct serum electrolytes;

Sodium, Calcium, Magnesium

Monitor and correct Blood glucose (especiallyavoiding hypoglycemia)

Monitor and maintain acid base balance within

the normal range

Monitor and maintain normal blood circulation


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Active maintenance of normal

homeostasis during the acute phase

Appropriate management of convulsions

and other complications



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Treatment of Convulsions Ensure normal homeostasis

Phenobarbitone at 20mg/kg bolus is the 1stline drug; if 2 doses 1 hr apart fail then

Phenytoin at 20mg/kg bolus is used. Thiscan also be used as 1stline especially when respiratorydepression is an important consideration

Refractory convulsions; Phenytoin andPhenobarb at maintenance dose plus either clonazepamor paraldehyde.


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Major Complications

Pulmonary (PPH, Mec Asp Synd)Hyperventilation, pulmonary vasodilators

Renal (Acute Tubular Necrosis; ARF)Fluid restriction, peritoneal dialysis, ultrafiltration

Cardiac (Myocardial Ischemia; Pump Failure)Ionotropic drugs

Gastrointestinal (Necrotizing Enterocolitis)

Antibiotics, GUT resting, surgery Haematological (DIC, Jaundice)

Blood platelate and clotting factor replacement


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other complications



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Experimental Methods

Oxygen free radical scavengers

Calcium channel blockers

Inhibitors of glutamic activity

These are presumed to work reducing the secondary celldamage following the initial hypoxic injury. None in

clinical use yet


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Clinical Prognostic Indicators

Low extended APGAR score

Severity of neurological syndrome

Additional organ complications

especially cardiac and renal

Poor socioeconomic status

particularly predicts later neuro developmental delays


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Summary

Perinatal asphyxia is an important cause of both

neonatal morbidity and mortality

It accounts for probably one quarter of allneonatal deaths in many countries

The mainstay of care is anticipation and effective

resuscitation at birth (BVM).

Supportive care seldom useful in severe cases

perinatal asphyxia for level 5 mbchb p

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