AUSTRALASIAN ANAESTHESIA 2017
Invited papers and selected continuing education lecture
Images in study used with permission from Dr DG Cowin, National Imaging Facility, Centre for Advanced Imaging, The University of Queensland
Epidural and combined spinal epidural (CSE) techniques have become the mainstay of labour analgesia in developed countries, but incidence of epidural catheter failure remains around 5-10 per cent1. Studies indicate that increasing prevalence of morbid obesity has led to higher rates of Caesarean delivery in this population cohort. The reliability of epidural catheterisation in these patients is becoming increasingly important for patient safety. Problems concerning labour epidurals in the obese parturient include difficult insertion due to poorly defined landmarks, displacement of epidural catheters after insertion, higher failure rates and greater need to revise catheter placement2. Obesity rates in Australian and New Zealand are increasing. Almost one in three Australian and New Zealanders are obese, defined as body mass index (BMI) >30 kg/m2. The population averaged BMI for adults is transitioning from the overweight (BMI 25-30 kg/m2) and into the obese range3, 4. The rising prevalence of obesity is reflected in all age groups as well as the generalised rising prevalence of obesity with age5-8. These overall trends include women of child-bearing age. Obesity has a dramatic impact on pregnancy outcome. Particularly increased prevalence of poor perinatal and neonatal outcomes, and increased risk of pregnancy complications such as postpartum anaemia, hypertension, pre-eclampsia, preterm delivery, emergency caesarean section, and gestational diabetes9. Epidural and combined spinal epidural (CSE) analgesia and anaesthesia is also commonly performed for the obstetric population. Sullivan and colleagues published on behalf of Australasian Maternity Outcomes Surveillance System (AMOSS) a 2010 cohort of “super-obese” pregnant women as defined by BMI >50 kg/m2 or weight >140 kg. The Caesarean section rate was 51.6 per cent compared with 31.7 per cent in the comparison group (p <0.01)10. Data from the Queensland Maternal and Perinatal Quality Council, demonstrate a trend toward assisted vaginal birth and caesarean section with increasing BMI (figure 1)11. This chapter aims to explore the challenges of epidural catheterisation in obese parturients. Potential contributions will be discussed, including the potential impact of obesity related anatomical changes.
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