BIRTH ASPHYXIA AND RESUSCITATION

BROUGHT TO YOU BY PAEDIATRIC TEAM SPONSORED BY DR HAMESE

PRESENTATION OUTLINE

• Birth AsphyxiA?• WhAt reAlly cAuses it?• pAthophysiology• hoW do these pAtients present?• Any diAgnostic criterion used?• WhAt’s the therApy?• prognosis After Birth AsphyxiA• complicAtions• resuscitAtion

Definition

• Failure to initiate spontaneous, sustained breathing after birth

• Impaired foetal gas exchange during labour • This can result in severe hypoxia• Foetal hypoxia is inadequate oxygenation before

delivery• This may predispose to birth asphyxia• Resulting to hypo-ventilation, hyper-capnia,

hypo-perfusion and metabolic acidosis

Aetiology/risk factors

• Placental insufficiency

antepartum intrapartum

Maternal age>35 or <16 Traumatic delivery

Maternal infections Prolonged/premature labour

Post term gestation Abnormal presentation

Multiple gestation Analgesics, sedation or drugs depressing the respiratory centre

Maternal drug abuse ROM>24hrs

Poly/oligohydramnios Meconium aspiration

Pathophysiology • Severe hypoxia in utero• Hypoxic insult continues, foetus loses consciousness• Neural centres cease to function because there is lack of O2

• Then foetus goes into primary apnoea• Hr remains unchanged, but soon decreases as the myocardium reverts to

anaerobic metabolism• Lactic acid gets released as a by-product of anaerobic metabolism• Insult continues, and if the foetus is in utero the foetus will gasp but if the

gasps fail to aerate the lungs, they fade away and the foetus enters a period of sec Apnoea

• Until this point circulation has been maintained but as terminal apnoea progresses then cardiac function gets impaired

• The heart eventually fails and if there is no intervention the baby finally dies

Apgar

APGAR score

Apgar cont…

Clinical Presen cont...

• Depends upon the aetiology, intensity, duration of inadequate oxygenation, plasma CO2 level and acidosis

• Asphyxia livida (stage of cyanosis): primarily due to respiratory failure with Apgar score of 4-6

• Asphyxia pallidum (stage of shock): due to combined respiratory and vasomotor failure with Apgar score of 0-3

Diagnostic criteria

• History of foetal distress and or MSL grade 2• Apgar score <=3 at 1 min or <=6 at 5 min• Arterial blood lactate >5mmol/L• Mixed acidosis– Ph <7.2 on arterial cord blood– Base excess >-10

– Pa CO2 > 55 mmHg

Prognosis

• Depends on associated factors, maturity of the baby, duration and intensity of hypoxia and acidosis including initiation of resuscitative measures in the delivery room

• Subsequent competent care and available facilities also influence the outcome following birth asphyxia

Prognosis after birth Asphyxia

• Apgar score < 5 at 10 min: nearly 50% death or disability

• No spontaneous breathing after 20 min: 60% disability in survivors

• No spontaneous breathing after 30 minutes, nearly 100% disability in survivors

Therapy

• Asphyxia must be anticipated and precautionary measures introduced

• Supportive measures

Complications (HIE)

• Acquired syndrome of acute brain injury characterised by neonatal encephalopathy in the first 3 days of life and evidence of intrapartum hypoxia in a term baby

• The immature brain is more resistant to hypoxic-ischemic events as compared to older children

• NE is characterised by an abnormal LOC, abnormal tone and primitive reflexes in the first week of life.

• Abnormal breathing and seizures may occur

HIE

• An evolving process initiated by the hypoxic-ischemic insult leading to decreased blood flow to the brain followed by the restoration of blood flow in an injured brain

• This initiates a cascade of pathways which includes accumulation of extracellular glutamate

• With excessive activation of glutamate receptors, ca influx and generation of reactive oxygen and nitrogen species leading to cell death and brain injuries.

Clinical presentation

• Cycling, posturing and myoclonus may represent seizure activity or lack of inhibition/control at a brainstem level.

• The Sarmat classification describes 3 clinical stages of encephalopathy

• ..\Documents\Stages of encephalopathy.docx

The HIE score

• Maximum score based on the infant’s clinical signs in the previous 24hrs, is recorded in each categ and totalled for the day

• Peak score of 10/less in the first 6 days with a score of 0 by day 7 predicts a N outcome

• Whereas a score above 15 and a score that is still abnormal on day 7 is predictive of abnormal outcome in 65%.

HIE Score pg 49 Handbook

Assessment tools in HIE

• Neuro-imaging – MRI: most app technique and is able to show diff

patterns of injury. If available, it can be done at age 10-14 days

– CT scan: less sensitive than MRI for detecting changes in the central gray nuclei

– Cranial U/S: not the best in assessing abnormalities in term infants

– aEEG: has prognostic value and is useful in diagnosing sub-clinical seizures

Management of HIE

• Aim is to treat symptoms and minimize further organ damage

• Correct standard management is more important than adding neuro-protective therapy such as hypothermia

Systematic management

• CNS– Perform a daily neurological assessment and on

admission– Treat recurrent and persistent seizures– If mod or severe NE is present at birth, induced

hypothermia may improve the outcome if commenced asap and not after 6hrs post-del

Hypothermia MOA

• Reduces cerebral metabolism prevents oedema• Decreases energy utilisation• Reduces cytotoxic amino acid accumulation• Attenuates secondary neuronal damage• Inhibits cell death• Reduces extend of brain damage– Death or severe disability at 18 months has been reduced

significantly

Respiratory system

• Monitor oxygen sats– If oxygen is needed but respiratory effort is good,

nasal CPAP is adeqaute

• Fluid balance and electrolytes– Intrinsic renal failure and SIADH commonly occurs– Initially restrict fluids to 40ml/kg/24 hrs with K

free 10% glucose and 0.45 % n saline– Monitor urine output, electrolytes, blood glucose

Parental counselling

• Explain the clinical condition• Document the parent’s version of events• Listen to their questions and explain the

management needed and keep them informed of the prognosis based on the daily clinical assessment

Prognosis and follow up

• Neurological examination and aEEG are only reliable when abnormalities are severe

• Early infant neuro-developmental assessment can be predictive of the outcome

• Cerebral palsy and intellectual disabilities are common in survivors of severe HIE and multidisciplinary follow-up is required.

Question 1

The severity of HIE can be graded as mild, mod and severe using the Sarnat classification. Of the ff, the criterion most consistent with Dx of mild HIE is:– Absence of seizures

– Low Apgar score– Need for assisted ventilation– Proximal muscle weakness– Decreased LOC

Potsisho ya bobedi

Several tests have been proposed to improve the prediction of long outcome following HIE. Of the ff, the most useful and practical test for determining the prognosis of HIE is– Cranial U/S– MRI– EEG

Vraag 3

The mother of a baby with HIE enquires about the possibility of a brain insult in her baby. Of the ff, the single most useful predictor of brain insult in her baby is evidence of:– Abnormal neurological exam findings– Cerebral oedema on cranial U/S– Elevated creatinine phosphokinase– Multisystem organ dysfunction

Resuscitation

• Est 5-10% of newborns need the initial steps of resuscitation

• About 3-6 % require these initial steps as well as assisted ventilation with bag and mask

• <1% require advanced resuscitation and in fact < 0.1% require chest compression

• < 0.05% require drugs

Dry the baby

• Drying helps keep a baby warm and clean and also stimulate breathing

• Dry baby with clean cloth and place where baby will be warm

THE GOLDEN MINUTE

• Check if the baby is crying and breathing• If baby is not crying or breathing well after

delivery, one need to help baby in the first minute

1. Position head on the side, neck slightly extended to keep airway open

2. Clear the airway: use a clean device Clear the mouth first to remove large secretions

before the baby gasps or cries. When using a suction device with a tube, insert

tube into side of the mouth not >5cm beyond the lips and not >2cm into nostril

3. Stimulate breathing: gently rub the back once or twice. Don’t delay or stimulate longer– Move quickly to evaluate breathing and decide if

ventilation is need– Evaluate the baby after clearing the airway and

stimulation– Check if baby is breathing well or crying

Now decide what care the baby needs after clearing the airway and stimulation

Baby not breathing well

• Begin bag and mask ventilation– Select the correct mask that covers chin, mouth and

nose. – Make a tight seal on the face to aerate the lungs

• Position the head slightly extended• Position the mask on the face• Make a firm seal between the mask and face

while squeezing the bag to produce a gentle movement of the chest

• Give 40 breaths per minute.

Evaluate the baby during ventilation

• Remember a baby who is breathing well will be crying or breathing quietly

• While the one who isn’t breathing well will be gasping or showing other signs of resp distress

• If the baby is grunting, cyanoses and having chest indrawing commence O2 and refer to neonatal unit

• Baby still not breathing, continue ventilation and call for help

Advanced resuscitation

Advanced resuscitation

• Hr normal but baby still doesn’t breath: wheck whether mother was never given pethidine or opioids.

• Baby not breathing or cyanosed, check O2 sats and if necessary give supplemental oxygen.

• Aim for sats resembling a healthy term baby

Heart rate <60

• Despite good ventilation• Start chest compressions

• To move O2 blood from lungs back to the heart.

• Allow enough time during the relaxation phase of each compression cycle for the heart to refill with blood

• Compress for 30 sec then check Hr• Hr >60 stop compressions

Stubborn HR

• Administer Adrenaline within 1 minute of adequate ventilation and chest compressions

• Give 0,01-0,03 mg/kg(equates to 0,1-0,3ml/kg of 1 in 10 000)

• Mix 1 ml of 1000 adrenaline with 9 ml of Saline to get 1 in 10000

• Repeat every few minutes, if Hr remains <60 despite effective ventilation and cardiac compressions

• Don’t ever forget Glucose

When to stop

• No Hr and breathing after ventilation for 10 minutes.

• No breathing after 20 minutes • Only gasping after 30 minutes

Indications for intubation

• Unsuccessful ventilation via face mask

References