Background: Chiari Malformation type 1 (CM-1) is a congenital anomaly where the hindbrain herniates into the foramen magnum. Consensus regarding the mode of delivery and anaesthetic management in patients with CM-1 remains controversial with regards to the risk of raised intracranial pressure (ICP)¹. We describe a patient with severe CM-1 who had elective caesarean section (CS) under general anaesthesia. Her airway was managed with a supraglottic device (iGel) after endotracheal intubation failed. To our knowledge this is a first report describing use of iGel in a patient with CM-1 during CS.

Case Report: A 32 yo with severe CM-1, extensive cervical syrinx and upper limb weakness was referred to the anaesthetic clinic at 13 weeks of gestation. Other risk factors were BMI of 40 and thrombocytopenia. Airway assessment found Mallampati 4, small mouth opening, big tongue and short thyromental distance. Discussions between anaesthetic, obstetric and neurosurgical teams concluded that the safest mode of delivery was an elective CS under general anaesthesia with neuroprotective measures. On the day of her surgery two senior anaesthetists attempted intubation with laryngoscope and bougie. At the second attempt bleeding in the oropharynx obscured the view. Oxygen saturations fell to 87% and an iGel was inserted as a rescue ventilation strategy. Due to the fact that good ventilation and oxygenation was achieved decision was made to continue the surgery using an iGel. There were no intra- or post-operative concerns and patient was discharged home 2 days later.

Discussion: Previous reports describe patients with CM-1 and difficult airway managed with neuroaxial blocks or awake fibreoptic intubation². In our patient regional anaesthesia was contraindicated due to raised ICP and thrombocytopenia. Awake fibreoptic intubation was considered but was abandoned in view of good ventilation achieved with iGel and to minimise any further airway stimulation. After failed intubation the iGel provided good oxygenation but PaCO2 on an arterial blood gas at the end of the surgery was 6.5kPa.

References: 1. Chantigian et al. Chiari I malformation in parturients. J Clin Anaesth (2002)14:201-5 
2. Semple et al. Arnold-Chiari malformation in pregnancy. Anaesth (1996)51:580-

Learning points: In case of failed endotracheal intubation an iGel can be successfully used in parturients with CM-1. However, hypercarbia is hard to control and potentially carries the risk of increasing the ICP.


09 / Anaesthetic management of a pregnant woman with Chiari Malformation type 1 following failed endotracheal intubation for caesarean section