ASPHYXIA NEONATORUM
DEFINITION Asphyxia neonatorum means non-establishment of satisfactory pulmonary respiration at birth. Its literal meaning is absence of pulse Clinically it is defined as failure to initiate and maintain spontaneous respiration within one minute of birth
INITIATION AND MAINTENANCE OF RESPIRATION Change in temperature Proprioceptive stimuli Clamping of the cord Raised PCO2 Lowered PO2 Chemoreceptors Respiratory centre Motor discharge as inspiratoory muscles Initiation of respiration Onset of grasp /cry /sigh Stretching of thoracic cage Re-routing of circulation Normal gaseous exchange
ETIOLOGY CONTINUATION OF INTRAUTERINE HYPOXIA BIRTH TRAUMA TO THE NEONATE PRENATAL AND INTRANATAL MEDICATION TO THE MOTHER
CONTINUATION OF INTRAUTERINE HYPOXIA….Contd FAILURE IN THE PLACENTAL FUNCTION Problem in the anatomical separation Extensive infarcts Retroplacental haemorrhage Thin small placenta Circumvallate placenta Hypertensive disorders of pregnancy Supine hypotensive syndrome Cord compression True knot in cord Vascular anomalies in cord
CONTINUATION OF INTRAUTERINE HYPOXIA MATERNAL HYPOXIC STATES Anaemia Eclampsia Cynotic cardiovascular disorders Status asthmaticus Emphysema Shock Hypotension
BIRTH TRAUMA MALPRESENTATION Oblique lie Breech Occipito posterior position PROLONGED HEAD COMPRESSION Malapplied forceps Ventouse extraction Prolonged 2nd stage -Contracted pelvis
BIRTH TRAUMA Increased intracranial tension Cerebral edema and congestion Increased intracranial pressure Asphyxia.
MEDICATIONS Prenatal Intranatal Eg.Morphine ,Pethedine,Anaesthetic agents
CLINICAL FEATURES It depend upon: Etiology Intensity and duration of oxygen lack Plasma Co2 excess Subsequent acidosis
ACCORDING TO INTENSITY AND DURATION OF OXYGEN LACK CLINICAL FEATURES Asphyxia Livida (Stage of cyanosis) Asphyxia pallida (stage of shock)
CLINICAL PICTURE ACCORDING TO DEGREE OF DEPRESSION Apgar score [4-6] asphyxia livida [primarly a condition of respiratory failure] Apgar score 0-3 asphyxia pallida [combined respiratory and vasomotor failure] Skin colour Blue Pale Respiratory movement Slow and irregular Absent or few gaps Muscle tone Present Flaccid Heart beats Regular –rate >100 Rapid, gets slower and feeble Reflex Grimace Absent
APGAR SCORING SCORE SIGNS 1 2 RESPIRATORY EFFORT Apneic Slow irregular Good crying HEART RATE Absent Low (Below 100) Over 100 MUSCLE TONE Flaccid Flexion of extremities Active body movements REFLEX IRRITABILITY No response Grimace Cough or sneeze COLOUR Blue,pale Body pink extremities blue Complete pink Total score – 10 , No depression – 7-10 , Moderate depression – 4-6 Severe depression – 0-3
CLINICAL SEQUENCES OF BIRTH ASPHXIA Initial response is hyperpnea and hypertension Primary apnoea Gasping attempt to breathe (if unresolved) – secondary apnoea Bradycardia and shock Diminished cerebral blood flow Cerebral haemorrhage Hypoxic ischaemic encephalopathy (if severe) – either death or handicap ( if the baby survives)
MANAGEMENT PROPHYLACTIC DEFINITIVE
PROPHYLACTIC Antenatal detection of high risk patients Scrupulous fetal monitoring, particularly in high risk pregnancy Intrapartum use of electronic fetal monitoring Judicious administration of anaesthetic agents and depressant drugs during labor.
Definitive Apgar rating
BABIES WITH APGAR SCORE 7-10 (PINK, BREATHING REGULAR HR > 100). The oropharynx and the nasopharynx are to be cleared off any mucus by suction O2 administration Re-assess the conditions at 5mts
BABIES WITH APGAR SCORE 4-6 [PERIPHERAL CYNOSIS, BREATHING IRREGULAR HR≥100…..Contd Place under a radiant heater and dry the baby Baby is put flat or slight head down position Immediate suction O2 administration (by bag and mask)
Stimulus to back and sole (gentle rubbing) If the above measures fail oral suctioning followed by tracheal intubation The tracheal tube is connected to resuscitation bag through which O2 is administered at the rate of 6-8 litres/ mt IPPV is maintained at the rate of 30-40 per mt. Gentle external cardiac massage is performed if HR is < 60/mt
If any history of administration of a central depressant drug to the mother give suitable antidote. Eg. Nalaxone hydrochloride 60g/kg IM (single dose) or 10g/kg i/v – it may have to be repeated. To combat metabolic acidosis – 8.4% sodiumbicarbonate 1mEq/kg in 5% dextrose (diluted 1:1) is given through umbilical or peripheral vein (at the rate of 1ml/mt)
BABIES WITH APGAR SCORE BELOW 4 (CENTRAL CYANOSIS) No breathing HR <100] Tracheal intubation and IPPV must be started immediately If IPPV is not available gentle mouth to mouth respiration If mother is received pethedine or morphine within 3hrs of delivery give Nalaxone 10g /kg i/v it may be repeated every 2-3mts.
Complications Immediate Delayed IMMEDIATE Cardiovascular – HTN, cardiac failure Renal – acute cortical necrosis, renal failure Liver function – compromised GI – Ulcers and necrotising enterocolitis Lungs – Persistent pulmonary HTN Brain – Cerebral edema, seizures.
DELAYED Retarded mental and physical growth Epilepsy – up to 30% in severe asphyxia Minimal brain dysfunction Prognosis a. It is dependent on normal maturity of the baby b. Duration and intensity of hypoxia c. Detection and treatment of fetal distress d. Facilities for immediate and competent management c. Detection and treatment of rare congenital anomalies.