Anticonvulsants for preventing mortality and morbidity in full term newborns with perinatal asphyxia

RHL practical aspects by Saloojee H

FIRST CONTACT (PRIMARY CARE) LEVEL

The early use of anticonvulsants in asphyxiated, term infants cannot be recommended.

Strategies to prevent perinatal asphyxia hinge on diligent obstetric care and good resuscitator skills. Measures such as the identification of high-risk pregnancies, fetal heart monitoring and monitoring progress on the partogram all assist in identifying the at-risk baby. However, their widespread use has not eliminated the problem of asphyxia, as their sensitivity and specificity as markers for fetal distress and asphyxia vary, but are generally poor.

Similarly, while it is imperative that all health professionals involved in perinatal care be trained and skilled in neonatal resuscitation, their ability to impact significantly on outcome is in many circumstances limited.

Ensure that basic principles of care are followed in managing an asphyxiated infant:

  • Keep the infant warm and dry.
  • Ensure that the infant does not have a low blood sugar (<2.5 mmol/l) and treat if detected.
  • Provide oxygen to the infant if he/she has signs of respiratory distress.
  • Refer to hospital as soon as possible (for special care).

REFERRAL HOSPITAL (SECONDARY CARE) LEVEL

The early use of anticonvulsants in asphyxiated, term infants is not beneficial.

Interventions to manage asphyxia are also often based on theoretical considerations or limited clinical evidence of benefit. The following recommendations reflect this, but may assist in limiting the development of further complications following severe perinatal asphyxia.

  • Restrict fluid volumes given in first 48 hours to 60 ml/kg. This may reduce the risk of cerebral oedema developing (personal opinion).
  • Boluses of plasma, colloid or crystalloid fluid at birth are contra-indicated unless there is clear evidence of blood loss. (personal opinion) (1).
  • Once initial resuscitation is complete, stop oxygen or reduce oxygen administered to the lowest possible concentration to prevent the generation of free oxygen radicals which may worsen the brain injury (personal opinion).
  • Do not feed moderately encephalopathic infants for the first 48-72 hours to reduce the risks of necrotising enterocolitis. Feeds, once commenced, often have to be given via the oro/nasogastric route because of the poor sucking and swallowing ability of moderately asphyxiated infants (personal opinion).
  • Temperature fluctuations (particularly hyperpyrexia) are noted in severely encephalopathic neonates. Pyrexia usually requires the discontinuation of supplementary heating, e.g. a warm incubator, and occasionally the use of an anti-pyretic agent (paracetamol) (personal opinion).
  • There is little justification for the routine use of antibiotics. Nevertheless, in practice, encephalopathic infants are usually started on ampicillin (or benzylpenicillin G) and gentamicin, as the cause for the asphyxia may be related to infection (personal opinion). There is, however, a high risk of aminoglycoside toxicity because of the associated renal injury, and gentamicin should preferably be stopped once interim blood cultures are negative. If no blood cultures were done, it is prudent to stop gentamicin after three doses have been given, unless there is strong evidence of an underlying infection.
  • Mannitol is of no benefit in the management of cerebral oedema in severely asphyxiated term infants (randomized controlled trial) (2).
  • There is no scientific evidence that anticonvulsants improve outcome after neonatal convulsions due to asphyxia. Thresholds for therapy vary even among experts. While Volpe (3) recommends prompt therapy when clinical seizures become apparent, Levene (4) prefers not to abolish all convulsions and only initiate therapy for frequent (>3 convulsions per hour) or prolonged convulsions (any fit lasting >/3 minutes).
  • There are few controlled studies on the use of anticonvulsants in the neonatal period. Phenobarbitone is usually recommended as the initial anticonvulsant (20 mg/kg loading dose intravenously over 10 minutes followed by 4 mg/kg/day). If convulsions continue despite the initial loading dose, a second loading dose of phenobarbitone can be administered (10 mg/kg). Second line anticonvulsants include phenytoin (20 mg/kg of body weight, slow infusion over 30 minutes, maintenance 5-10 mg/kg of body weight/day, intravenously only). The use of diazepam is discouraged in neonates because of its short half life and side-effects.
  • Anticonvulsants can be stopped once the baby is neurologically normal or has had no seizure activity for a week. However, there is a 30-40% risk that seizures may recur; this outcome is not influenced by continuing anticonvulsant therapy after the initial seizures have stopped (cohort study) (5).

AT HOME OR IN THE COMMUNITY

Not applicable

References

  • Roberton NR. Use of albumin in neonatal resuscitation. European journal of paediatrics 1997;156:428-431.
  • Kecskes Z, Healy G, Jensen A. Fluid restriction for term infants with hypoxic–ischaemic encephalopathy following perinatal asphyxia. In: The Cochrane Library: Issue 3, 2007. Chichester, UK: John Wiley & Sons, Ltd.
  • Higgins RD, Raju TN, Perlman J, et al. Hypothermia and perinatal asphyxia: executive summary of the National Institute of Child Health and Human Development workshop. J Pediatr 2006;148:170–175.
  • Volpe JJ. Neurology of the newborn. ed3. Philadelphia, WB Saunders, 1995.
  • Levene MI. Management of the asphyxiated full term infant. Archives of disease in childhood 1993;68:612-616.1995;72:F97-F101.
  • Hellström-Westas L, Blennow G, Lindroth M, et al. Low risk of seizure occurrence after early withdrawal of antiepileptic treatment in the neonatal period. Archives of disease in childhood 1995;72:F97-F101.
  • McGuire W. Perinatal asphyxia. BMJ Clinical Evidence. URL: http://clinicalevidence.bmj.com/ceweb/conditions/chd/0320/0320.jsp (accessed 1 October 2007)

This document should be cited as: Saloojee H. Anticonvulsants for preventing mortality and morbidity in full term newborns with perinatal asphyxia: RHL practical aspects (last revised: 10 October 2007). The WHO Reproductive Health Library; Geneva: World Health Organization.

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