Anaesthesia for caesarean delivery in women with class 3 obesity: a retrospective cohort study from the north-west of England (2022-2023).

BACKGROUND

The Royal College of Anaesthetists (RCOA) and the Royal College of Obstetricians and Gynaecologists (RCOG) have recommended standards for pregnant women with a body mass index (BMI) ≥40 kg/m2. These include achieving specified rates for neuraxial anaesthesia and conversion from neuraxial to general anaesthesia (GA) during caesarean delivery (CD), 100% attendance at the anaesthesia antenatal clinic, re-weighing in the third trimester, and anaesthesia provision by a specialty trainee year 6 (ST6) or above.

METHODS

Records of 760 women with BMI ranging from 40.0-49.99 kg/m2 (89.7%), 50.0-59.99 kg/m2 (8.9%) and ≥ 60 kg/m2 (1.4%) undergoing a CD were reviewed across nine maternity units in the north-west of England. We aimed to analyse the variations in anaesthetic technique across the BMI cohorts, assess adherence with the proposed standards and explore the documented incidence of pain during CD (PDCD).

RESULTS

Neuraxial anaesthesia was successfully utilised in 92.6% women. Spinal anaesthesia rates declined as BMI increased from ≥40-49.99 kg/m2 (81.1%) to ≥50-59.99 kg/m2 (67.2%) to ≥60 kg/m2 (45.5%), (P =0.0001), whilst combined spinal epidural (CSE) use increased (4% vs 19.4% vs 45.5%, P <0.0001). No differences were observed in the primary GA (3.7%; P =0.12) or the neuraxial to GA conversion rates (3.8%; P =0.54) across the BMI cohorts. The neuraxial anaesthesia standards for all CD categories were met by at least 66.7% of all hospitals, whilst the neuraxial to GA conversion standards for elective CD were met by only 33.3%. PDCD was documented in 6.1% and only 24.9% of women were re-weighed in the third trimester. Anaesthetic clinic attendance was recorded in 57% whilst a ST6 or above provided anaesthesia to 87.1% of women.

CONCLUSION

As BMI increases, anaesthetists tend to favour a CSE technique over spinal anaesthesia. Maternity units found it challenging to comply with the specified RCOA/RCOG standards.