MANAGEMENT OF PERINATAL ASPHYXIA
DR.RHISHIKESH
THAKRE.
DM (Neonatology),
MD, DNB (Ped), DcH, FCPS.
Perinatal asphyxia is one of the
leading causes on neonatal morbidity and mortality in our country. A scientific
and rationale approach to its management is therefore necessary to have any
impact on the outcome.
A
good history and relevant clinical examination is mandatory for optimum care.
History should
specifically look at the intra partum events like malpresentation,prolonged
labor,difficult labor,meconium
passage,antepartum haemorrhage,non
reassuring fetal heart rate patterns on intrapartum monitoring,and obstetric accidents.In
some conditions asphyxia would set in inspite of no
identifiable risk factors and then conditions like cord compression,cord
prolapse,neuromuscular disorders,maternal
medications,congenital malformations and maternal hypothyroidism should be looked
for specifically.
Clinical
examination by itself can give clue to the aetiology
of asphyxia like - Meconium staining (MAS) ,large baby (difficult
labor),evidence of caput (prolonged second stage),SGA (intrauterine
asphyxia),depressed baby (drugs,neuromuscular
disorder),bruises(difficult / traumatic labor),anemia(antepartum
haemorrhage),polycythemia (SGA,precipitate labor)and dysmorphism
(occult anomalies).
BASIC
CARE :
Should be a daily
routine in the management of all these babies -
1.Strict asepsis.
2,Ensure neutral thermal environment.
3.Monitor vital parameters
HR,RR,BP,and Pulse Oximetry.
4.Urine output.
5.Daily weight.
6.Nutrition.
ANTICIPATION IS THE KEY TO THE MANAGEMENT.
TIMETABLE OF
COMPLICATIONS IN ASPHYXIA:
1.Seizures First 48 hours.Severe the asphyxial insult
early is the onset and refractory are the seizures.
2.Oliguria Eight hours and after, on maintenance IV fluids.Severe the insult and prolonged the insult longer is
the renal damage.
3.Hypoglycemia Nadir of blood glucose
physiologically takes place by 2 hours postnatally
and in conditions like asphyxia the onset is likely to be early .The best
predictor of its occurrence would be therefore cord blood glucose .A high value is a predictor of early rebound hypoglycemia in the neonate.
4.Hypocalcemia After 72 hours unless complicated by associated conditions
like maternal diabetes,maternal hyperparathyroidism
etc.
5.Shock Timing depends on the aetiology.Hypovolumic
shock is seen in labor room due to obstetric accidents,cardiogenic
shock usually after 6 hours but more so
by the underlying severtity of the asphyxial insult , septic shock usually after first 6 hours
depending upon the infection severity, and rarely neurogenic
shock after 72 hours in stage 3 HIE.
6.Hematological complications Intra partum asphyxia ,meconium passage,preeclampsia cause neutropenia
which is self limitng and lasts for not more than 24
hours thus mimicking sepsis.Anemia and polycythemia usually is determined by the obstetric events.Thrombo
cytopenia sets in by 24 hours and is usually associated
with bone marrow depression. DIC occurs as a terminal event in the course of
asphyxia.
7.Electrolyte imbalance Hyponatremia is usually due to
SIADH and manifests by 24 hrs.Hyperkalemia is due to
renal impairment and usually seen by 36 hrs.Critical
evaluation of fluid administered is therefore important.
8.HIE Occurrence is determined by timing of asphyxia,its
severity, and its duration.If 48 hours have passed
and no neurological signs have appeared its unlikely to occur thereafter.
1.Need for intubation,cardiac massage,and
administration of drugs in labor room are the singlemost
markers to predict early occurrence of seizures.Persistent
low apgar scores at 5 mts
or more,cord blood ph < 7 are good objective
markers .
2.Basic evaluation should
include review of maternal drugs,blood glucose, serum
calcium and serum electrolytes. Further evaluation is based on clinical
suspicion.
3.Seizures in asphyxia
usually die down or burn themselves by 48 hours. Not all seizures require
treatment. Onlylif seizures are more than 3 in a hour
or lasting for 3 mts
or more they warrant anticonvulant.There is no
role of prophylactic anticonvulant therapy in asphyxia.Phenobarbitone,Phenytoin,initially by loading dose
followed by maintenance dose are the first line drugs.Concomitant
evaluation and correction for treatable causes like hypoglycemia,hypocalcemia,hypomagnesemia,and
pyridoxine deficiency is required.
4.Radiological evaluation is
required only in intractable seizures where metabolic workup is negative.
5.In refractory
seizures use of drip of midazolam,lorazepam or
diazepam may be required. Role of sodium valproate is
occasional. Use of newer anticonvulants like lamotrigene,clobazam,gabapentin
etc is not well known in neonates.
Management of renal failure.
1.Urine output is by
itself not a reliable marker of renal insufficiency hence renal parameters need
to be monitored.
2.Fluid restriction is
required once intrinsic renal failure sets in. A careful evaluation of
electrolytes would direct the fluid management.
3.Daily monitoring of
urine output, urine specific gravity, and body weight are adjuvant to basic
care.
4.Rarely peritoneal
dialysis is required in case of persistent oliguria.
1.Hypoglycemia
needs to be corrected by 10 % D.Only if it is symptomatic it warrants a bolus otherwise in
asymptomatic cases maintenance infusion is all that is required.Ensure
drip infusion rate preferably by infusion pump.
2.Only symptomatic hypocalcemia needs correction.Evaluate
for hypomagnesemia in case of persistent hypocalcemia.
3.Hyponatremia should be
anticipated and prevented by restricted fluid
administration.
1.Hypovolumic shock needs
replacement with fluids, plasma, or blood.Isolated
diastolic shock is the earliest marker of impending shock.Unexplained
tachycardia is a good bedside clue.
2.Cardiogenic shock warrants
use of pressors like dopamine
and / or dobutamine. In case of refractory shock inspite
of use of pressors of 20 microgram/kg/mt steroids may be tried.
3.Role of CVP to
determine the cause of shock is not routinely done or advocated,
4.Septic shock should be
suspected based on intrapartum risk factors for
sepsis, core axillary mismatch and results of sepsis
screen.
Clinical predictors of poor outcome
1.Refractory seizures.
2.Neurological defecit at the end of first week.
3.HIE stage 3 at the
time of discharge.
KEY POINTS :
1.Anticipation is the key in
prevention and management of asphyxia.
2.The manifestations
are determined by the timing,severity and duration of
asphyxia.