The rising number of morbidly obese people in the UK population has prompted anaesthetists to write new guidelines for managing these higher risk patients, emphasising the need for training and suitable equipment.
In England nearly 3% of women and 1% of men are morbidly obese (with a body mass index (BMI) of >40), and well over a fifth of the population are obese (BMI >30), government figures show.
The new guidelines, issued by the Association of Anaesthetists of Great Britain and Ireland, say that each hospital should have a named consultant anaesthetist responsible for making sure that staff and facilities are appropriately prepared for the perioperative management of morbidly obese patients. Each operating theatre should also have a member of staff with this responsibility.
"Many clinicians are aware of an increasing number of morbidly obese patients. It really is becoming significantly more common," said Alastair Chambers, consultant anaesthetist at Aberdeen Royal Infirmary, who led the committee that wrote the guidelines.
"We do know that these patients suffer a higher incidence of anaesthetic complications, but we don't have hard data to quantify this. It is timely to set these guidelines in place to minimise the chances of these complications," Professor Chambers said.
The guidelines say that every major hospital is likely to encounter patients weighing more than 150 kg and that some of these patients will present in emergencies.
Morbidly obese patients have a greater risk of developing deep vein thrombosis, wound infection, and respiratory complications. They are also more likely to need intensive care after an operation.
In such patients intubation is often more difficult, low oxygen saturation during general anaesthesia is more common, and regional anaesthesia is harder where landmarks are obscured.
The guidelines say that all trained anaesthetists should know how to manage such patients.
"They need to be familiar with the equipment and the risks that these patients present. Formally recording a patient's weight and height is a good start," said Professor Chambers.
Clinicians need to make sure they know the weight tolerances of operating theatre beds, when flat and when tilted, he said.
"Calculating the dose of drugs that you should give these patients is not always straightforward," he added.
He pointed out that staff were also at risk, highlighting back pain as a potential consequence of unsafe lifting. The guidelines say that mandatory courses on manual handling should cover morbidly obese patients.
Each hospital should have at least one theatre and several critical care beds prepared for morbidly obese patients and should develop clear guidance for staff in out of hours emergencies.
Hospitals should also make sure they have sufficient supplies of larger gowns, tourniquets, and blood pressure cuffs.
The guidelines are available at http://www.aagbi.org/.
BMJ 2007;335:275 (11 August), doi:10.1136/bmj.39300.400266.DB