P89
ANAESTHETIC CHALLENGES OF MANAGING A GIANT OCCIPITAL ENCEPHELOCOELE IN A NEONATE WITH ASSOCIATED CHIARI 3 MALFORMATION: A CASE REPORT
N. Mdzinwa, University of Pretoria, South Africa
Introduction:
A Chiari 3 Malformation is characterized by a high cervical or occipital encephalocoele, occipital or cervical bony deformities and a small posterior fossa with caudal displacement of the hindbrain. There is a paucity of data on the anaesthetic management of neonates with Chiari 3 malformations due to high mortality rates. Challenges faced by anaesthetists while managing neonates with a giant occipital encephalocoele include airway management, positioning, fluid and blood management, temperature management, drug dosing and associated conditions. The aim of this case report is to discuss how these challenges were overcome while managing a premature neonate.
The case:
A 10-day-old preterm neonate, born at 36 weeks gestation to an unbooked mother, presented for surgical correction of a Giant Occipital Encephalocoele (106 x 141 x 158 mm) associated with a Chiari 3 malformation. MRI of the brain revealed no neural tissue within the sac. Deficient C1 and C2 posterior arches and kinking of the high cervical cord with resultant CSF obstruction rendered the neck unstable. The airway was managed in a lateral position with strict neutral position of the neck using a video laryngoscope. Prone position, as required for optimal surgical exposure, without applying pressure on the c-spine and the face required innovation. The neonate became hypotensive immediately after the encephelocoele was drained. Fluid management was guided by continuous invasive blood pressure monitoring and arterial blood gas (ABG) sampling. Packed red blood cells were transfused at 10ml/kg/hour from the start of the case with a target haematocrit of 30%. Drugs were dosed at an ideal body weight of 2.8kg based on estimated gestation from the history, which was likely inaccurate as the neonate’s postoperative weight was 3.3kg.
Discussion:
The neonate had relatively few negative prognostic factors and did well in the perioperative period. Intubation techniques described in the literature include pre-induction drainage of the encephalocoele, maximum atlantoaxial extension and caudal displacement of the mass with gentle traction. A newer technique is hybrid pillow designs which would allow the patient to be in a supine position with no pressure on the mass. A lateral position with strict neutral head position seemed the most suitable choice for this neonate with an unstable C-spine. The use of a video laryngoscope and a three-man technique aided in tracheal intubation which proved difficult. A method for fluid replacement is required after the encephalocoele is drained, without fluid overloading the neonate. We advise the use of invasive monitoring and ABG analysis to guide this replacement. Weight estimation to facilitate drug and fluid dosing is also challenging. We utilized nomograms to estimate the neonate’s ideal body weight, which is the best available tool. Future research should explore utilizing advanced imaging to estimate the weight of the mass.
References:
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