Management of Asphyxia

1. Management of B irth Asphyxia Presenter :Dr Jecinter Modi-Juma

2. Outline Diagnosis Management principles Follow up Complications Summary

3. Why is it important? Occurs in 1-6 per 1000 live term births in developed countries Number 5 leading cause of under 5 mortality Significant cause of cerebral palsy and developmental delay WHAT SHOULD BE DONE Early recognition of maternal risk factors Decision on when and where to deliver Close surveillance of high risk labor

4. Prenatal detection of Risk of Asphyxia: . Only possible in half of cases Predictors of low Apgar score: Fetal movement counting Non-stress test Fetal biophysical profile Abnormal fetal heart rate (FHR) recording Fetal scalp Ph monitoring- is the best but invasive

5. DIAGNOSIS History , physical examination and laboratory tests Profound metabolic or mixed acidemia (pH < 7) in an umbilical artery blood sample, if obtained Persistence of an Apgar score of 0-3 for longer than 5 minutes Neonatal neurologic sequelae ( Multiple organ involvement AAP / ACOG criteria for asphyxia severe enough to cause neurological injury

6. Investigations Physical examination: according to Sarnat and Sarnat criteria To rule out multi organ damage Rule out other causes of CNS dysfunction Prognosis Monitoring of progress

7. Laboratory Tests Blood gas analysis Renal function tests and electrolytes Liver function Tests Coagulation test Monitoring of blood sugars Cardiac enzymes

8. Imaging Cranial Ultrasound CT MRI EEG

9. Treatment Prevention of intrauterine asphyxia Supportive treatment Treatment of complications Neuroprotective strategies

10. Supportive Treatment Aim is to avoid any further brain injury Initial newborn resuscitation and stabilisation ensures adequate oxygenation and ventilation using bag mask ventilation Several clinical trials : room air resuscitation for infants with perinatal asphyxia is as effective as resuscitation with 100% oxygen. Infants resuscitated with room air have been shown to have lower circulating ROS International Liaison Committee on Resuscitation (ILCOR) recommendations include initiating neonatal resuscitation with concentrations of oxygen between 21-100%

11. Ventilatory support Incase of respiratory failure, start mechanical ventilation aiming at PO2 (80-100mmHg) and PCO2 (35-45mmHg) within normal. Hyperoxia /hypoxia and hypercabia / hypocabia may cause further injury to the brain.

12. PERFUSION Maintain adequate perfusion by use of intravenous fluids Maintain blood pressure within normal Correct deficit by slow infusions of N/S Monitor urine output: 1ml/kg/hr Ensure normal hematocrit >40% Monitor CVP

13. METABOLIC SUPPORT Monitor electrolytes Na+,K+,Cl-, calcium, magnesium and correct the abnormalities These are usually deranged in ATN and in SIADH Maintain RBS at 3.3- 5.5 mmol /L Maintain normal acid base balance

14. HYPERTHERMIA MANAGEMENT Avoid hyperthermia For 1 degree increase in temprature = 3-4 fold increase in risk of death/disability In therapeutic hypothermia aim to get core (rectal) temperature to 33-35⁰ C for 72 hours Followed by gradual rewarming for the next 6-8 hours

15. HYPERTHERMIA MANAGEMENT It has been shown from randomized trials that cooling 3-4°C below baseline temperature applied within a few hours not later than 6 h of injury is neuroprotective Whole body cooling VS head cooling This form of therapy is still under investigation

16. Mechanism of action of therapeutic hypothermia Reduced metabolic rate and energy depletion Decreased excitatory transmitter release Reduced vascular permeability, edema, and disruptions of blood-brain barrier function Reduced alterations in ion flux Reduced apoptosis due to hypoxic-ischemic encephalopathy

17. Possible complications of hypothermia Rx Coagulation defects, leukocyte malfunctions, pulmonary hypertension, worsening of metabolic acidosis, and abnormalities of cardiac rhythm, especially during rewarming. These are still controversial and under investigation

18. SEIZURE CONTROL Common in moderate to severe asphyxia Causes further brain injury and future risk of epilepsy Usually self –limited and confined to early days of life. Start with phenobarbitone loading dose at 20mg/kg , can repeat after 15 minutes if no response Phenytoin used if no response to phenobarbitone Other drugs: benzodiazepines like midazolam and clonazepam Complicates ventilation, oxygenation and blood pressure control

19. DIET Generally kept NPO in the first 3 days of life in moderate to severe asphyxia till level of consciousness improves Start with trophic enteral feeds at 5mls 3 hourly and increase based on individual progress Watch for signs of NEC Parenteral nutrition

20. Potential neuroprotective strategies

21. FUTURE THERAPIES 1) Monosialogangliosides –Cell membrane constituents 2) Growth factors –Nerve growth factor –Insulin-like growth factor 3)Gene therapy –Bcl-2 (potent inhibitor of cell death pathways) 4) Intracellular calcium buffering –Calbindin-D28k (intracellular calcium-binding protein which acts as a mobile calcium buffer) 5) Anti-NMDA receptor immunization

22. Predictors of outcome Failure to establish respiration by 5 minutes of life Apgar score of 3 or less at 5 minutes Onset of seizures with in 12 hours Refractory seizures Stage III HIE Persistent oliguria (<1 ml/kg/hr) for the first 36 hrs of life Inability to establish oral feeds by 1 wk Abnormal EEG & failure to normalize by D7 Abnormal CT, MRI in neonatal period

23. Follow up Goal: detect impairments and intervene early Monitor growth Neurologic examination to identify those who require intensive follow-up Visual and hearing tests Multidisciplinary

24. REFERENCES Averys Neonatology 6 th Edition Medscape Nelsons Textbook of paediatrics 19 th Edition