Anaesthetic care for the obese patient

Surgical teams today are encountering increasing numbers of obese and morbidly obese patients – presenting significant clinical and practical challenges for healthcare teams. Just over a quarter of adults were classified as obese in 2010 (Body Mass Index (BMI) 30 kg/m2) and this number is expected to continue to rise.1 In the last decade, the number of bariatric (weight-loss) surgery procedures in England also increased 30-fold – from just 261 in 2000/01 to over 8,000 in 2010/11.1 Surgery for these patients requires special management and planning to minimise the risks for both the patient (as well as the team involved in their care), and to ensure the dignity and comfort of the patient throughout their patient journey. In particular, the approach to anaesthesia for the obese patient requires special consideration. A report by the Royal College of Anaesthetists (RCA) found that, all too often, obesity has not been identified as a risk factor for airway difficulty and there has been a failure to modify anaesthetic technique, leading to preventable death or mortality. The 4th National Audit Project of the RCA (NAP4)2 examined a large cohort of major airway complications (resulting in death, brain damage, emergency surgical airway or unexpected ICU admission) and found that obesity was a significant factor. Complications highlighted by the audit included:

• An increased frequency of aspiration and other complications during the use of supraglottic airway devices (SADs)
• Difficulty at tracheal intubation and airway obstruction during emergence or recovery.

In addition, when rescue techniques were necessary in obese patients they failed more often than in the non-obese. In view of the trends in obesity in the UK and other developed countries, the RCA warned that the number of patients at risk of such events is ‘almost certain to increase’. In 2009, the unique challenges this patient group presents prompted the launch of a specialist group, the Society for Obesity and Bariatric Anaesthesia (SOBA), which aims to raise quality standards and improve the safety of surgery for obese patients. The society was established by SOBA’s chairman, Nick Kennedy, consultant anaesthetist and intensivist, Taunton and Somerset NHS Trust; and vice-chairman, John Cousins, consultant anaesthetist, Imperial College Healthcare NHS Trust. “When SOBA was first established, bariatric (weight-loss) surgery was a new and expanding specialty in the UK. There were many anaesthetists involved with this work, at the time, but no overarching body to represent this area of practice,” commented Dr Kennedy.“Our main aim was to provide a forum for quality improvement and education in the field of bariatric anaesthesia. However, it quickly became apparent that the clinical issues that we were facing, in our specialty, were also being experienced by other anaesthetists dealing with morbidly obese patients, and there was an opportunity to share our knowledge more widely. “Morbidly obese patients present significant clinical issues for all anaesthetists and are certainly higher risk than the average patient. In general, the principle is ‘the bigger the patient, the bigger the risk’. SOBA has expanded its remit to improve outcomes across all surgical specialties, though its education and training programmes.” In particular, Dr Kennedy pointed out that there is a lack of specific training on managing the morbidly obese patient, during mainstream anaesthetic training, which must be addressed: “Experts who perform these procedures regularly become very good at it. But those who do not perform these procedures with any frequency are often anxious, lack confidence and do not have the right equipment or set up to do it well. This is particularly true of anaesthetic trainees. “However, the RCA audit also shows there is a general lack of awareness that obese patients present serious issues – they are not being managed appropriately, which can cause problems.” Such problems are pertinent to all anaesthetists and Dr Kennedy provided an overview of some of the key factors that should be considered: