A patient was booked for elective caesarean section. Spinal anaesthesia was technically difficult due to severe obesity and resulted in a high block above T1, associated with refractory hypotension and difficulty breathing. The patient required significant doses of vasopressors, including phenylephrine, ephedrine, and metaraminol. This led to an overshoot in blood pressure, and the patient became hypertensive with a frontal headache intraoperatively. Both hypertension and headache resolved after stopping vasopressor medication.

After surgery, whilst on the ward, the patient suffered two seizures. A CT brain demonstrated a subarachnoid haemorrhage. The patient was transferred to another Hospital for further management.

Commentary:

The risk of high spinal block in parturients undergoing caesarean birth increases with BMI, with an odds ratio of 6.3 in BMI >= 50 compared to BMI < 30 kg/m² in one cohort study.¹ Caval compression from the gravid uterus and abdominal panniculus are thought to reduce lumbar CSF volume via engorgement of epidural veins.  Respiratory distress associated with high spinal block is exacerbated by increased work of breathing in severe obesity, particularly when supine. Non-invasive blood pressure measurement can also be challenging in severe obesity, which can lead to the late detection of hypotension and subsequent overshoot. Consideration should be given to invasive blood pressure monitoring where it is difficult to obtain accurate readings.   

The haemodynamic effects of high spinal anaesthesia for caesarean delivery are exacerbated by aortocaval compression, even if some lateral tilt has been applied.  A full left lateral position should be used if the woman has refractory hypotension.³

This case illustrates the importance of imaging for women who develop new acute neurological symptoms and are not known to be epileptic or eclamptic.  The risk of subarachnoid haemorrhage following caesarean delivery is rare.  The majority of cases are due to ruptured intracranial aneurysms. A sudden rise in blood pressure may be associated with hypertension-induced aneurysmal rupture or pial vessel rupture.³ 

References

1. Lamon AM, Einhorn LM, Cooter M, Habib AS. The impact of body mass index on the risk of high spinal block in parturients undergoing cesarean delivery: a retrospective cohort study. J Anesth; 2017; 31: 552–8
2. Bamber JH, Lucas DN; on behalf of the MBRRACE-UK anaesthesia chapter-writing group. Messages for anaesthetic care. In: Knight M, Nair M, Tuffnell D et al., eds. Saving Lives, Improving Mothers’ Care: Lessons learned to inform maternity care from the UK and Ireland Confidential Enquiries into Maternal Deaths and Morbidity 2013–15. Oxford: National Perinatal Epidemiology Unit, University of Oxford; 2017: 67–73.
3. Bateman BT,  Olbrecht VA,  Berman, MF, Minehart, RD, et al., Peripartum Subarachnoid Hemorrhage: Nationwide Data and Institutional Experience. Anesthesiol 116(2) 2012 :324-333