Anaesthetic management of parturient posted for elective caesarean section with cerebral arteriovenous malformation

Abstract

Sir, Cerebral arteriovenous malformation (AVM) has a prevalence of 0.01–0.05%.[1] We present a case of a 25-year-old primigravida at 37 weeks gestation, a known case of left frontoparietal AVM and epilepsy posted for elective cesarean section. Five years ago, she presented with weakness of the right upper and lower limbs. She was diagnosed with left frontoparietal AVM [Figures 1 and 2]. She had multiple seizure episodes and was started on T. levetiracetam 500 mg BD, T. lacosamide 200 mg BD, T. clobazam 10 mg BD, and T. phenytoin 100 mg OD.Figure 1: MR venogram showing large draining veins joining superior sagittal sinusFigure 2: MRI of the brain showing numerous flow voids along the left frontoparietal lobe and atrophy of neuroparenchyma in the left cerebral hemisphereA pre-anesthetic evaluation was done. She gave a history of seizure attacks 4 days back. She was premedicated with oral pantoprazole 40 mg and metoclopramide 10 mg 1 h before surgery and kept nil per oral for 6 h. All antiepileptic drugs were continued. In the operating room, the wedge was placed under her right hip. Standard pre-induction monitors were attached and intravenous (IV) access was secured. The cesarean section was done under general anesthesia. Rapid sequence induction was performed with IV thiopentone 5 mg/kg and rocuronium 1.2 mg/kg. The patient was intubated with a 7 mm internal diameter endotracheal tube after 1 min. Anesthesia was maintained with oxygen, air, and isoflurane. After delivery of a live female baby of 2.2 kg, IV fentanyl 2 mg/kg, midazolam 2 mg, ondansetron 4 mg, and oxytocin infusion were given. The patient was hemodynamically stable and the postoperative pain was managed with an ultrasound-guided bilateral transverses abdominis plane block. The parturient was extubated and shifted to the intensive care unit (ICU). She had an uneventful postoperative period. Cerebral AVM usually presents with intracranial hemorrhage, seizures, focal neurologic deficits, and headaches.[2] The symptoms of AVM may be mistaken with pregnancy-associated disorders such as eclampsia. computed tomography (CT) and magnetic resonance imaging (MRI) (with abdomen shielding) help to confirm the diagnosis. It is mandatory to document the neurological deficits, optimize antiepileptics, counsel regarding the potential complications, and the need for neurosurgery. The neurosurgeon and intervention radiologist were alerted regarding the patient’s delivery plan and the neurologist’s opinion was taken to optimize the antiepileptics. There are no conclusive data regarding the risk of AVM hemorrhage during pregnancy.[3,4] AVM hemorrhage during pregnancy is associated with 28% maternal and 14% neonatal mortality. Most centers prefer elective cesarean sections even though normal vaginal deliveries do not increase the risk of AVM hemorrhage. Uterine contractions during normal labor may increase the stress on the abnormal veins. Hence, if vaginal delivery is planned, epidural labor analgesia and assisted instrumental vaginal delivery are recommended. For cesarean section, general anesthesia is preferred over regional anesthesia to avoid neurological complications. cerebrospinal fluid (CSF) release with subarachnoid block causes a sudden change in the transmural pressure across the AVM predisposing it to rupture. An accidental intravascular injection of local anesthetic containing epinephrine test dose during the initiation of the test dose following epidural anesthesia could predispose to the rupture of AVM. The main aim of anesthetic management is to maintain the mean arterial and intracranial pressure within the normal range to reduce the risk of hemorrhage and cerebral hypoperfusion. Hypertensive responses to laryngoscopy and extubation should be obtunded. Thiopentone is the preferred induction agent.[5] Ketamine is avoided as it can increase blood pressure and intracranial pressure. Suxamethonium has to be avoided and a high dose of rocuronium 1.2 mg/kg is used for rapid sequence induction.[6] General anesthesia with controlled ventilation is used to keep PaCO2 at a low normal range to minimize cerebral vasodilatation and rise in intracranial pressure. Hypotension during surgery is avoided by optimal fluid resuscitation and vasopressors. Supine hypotension is avoided by the use of a wedge under the hip. Thus, multi-disciplinary care involving an obstetrician, intervention radiologist, neurologist, neurosurgeon, and obstetric anesthesiologist is required to ensure good pregnancy outcomes in these high-risk parturients. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.