Regional Anaesthesia in the Diabetic Patient

• Avoid tracheal intubation in a patient cohort at higher risk of difficult airway (e.g. due to obesity, stiffer soft tissues)
• Reduce risk of aspiration in patient cohort at higher risk due to gastroparesis and the effect of certain diabetic drugs
• Reduced risk of PONV
• Faster return to normal diet
• Therefore faster return to normal medication regimen
• Reduced risk of complications such as hypoglycaemia, hyperglycaemia, need for VRII or DKA
• Promotes 'DrEaMing' i.e. faster return to normal diet and mobilisation
• Attenuates surgical stress response, which can cause glucose dyscrasia
• Opioid-sparing effect, which may be more beneficial in diabetic patients owing to the greater negative sequelae of PONV and ventilatory impairment in this group
• Reduced length of stay
• Potentially reduced incidence of chronic post-surgical pain

• Diabetic neuropathy causes irreversible structural nerve changes including increased strength-duration time-constant and increased rheobase (increased excitability)
• This makes diabetic neuropathic nerves harder to stimulate, requiring stimulation thresholds >1mA vs. conventional thresholds (~0.4mA)
• NB this is not true of diabetics without neuropathy
• There is also a high inter-individual variability in required stimulation threshold
• Failing to account for these greater stimulation threshold may lead to nerve damage through direct trauma or LA toxicity due to aberrantly close positioning of needle to nerve

• Local anaesthetics may add to the existing metabolic injury in diabetic neuropathic nerves ('double-crush' theory)
• In one study, the risk of post-operative neurological dysfunction in patients with pre-existing neuropathy following neuraxial intervention was 0.4%
• Use of vasoconstricting adjuncts may increase the risk of neuronal toxicity and, given the longer duration of block in those with diabetic neuropathy anyway, these should be avoided

• The nerves of those with diabetic neuropathy are more sensitive to LA, leading to higher likelihood of success and prolonged block duration
• This holds true for both neuraxial and peripheral nerve block
• This arises because:
• Reduced lidocaine concentration is required to block sodium channels and cause motor blockade
• Reduced vascular supply to neuropathic nerves prolongs the duration of action of local anaesthetics


• This can lead to complications such as pressure ulcers from prolonged immobility due to dense motor block

• Diabetes and hyperglycaemia are risk factors for infection following regional anaesthesia, including catheter-based techniques
• Higher incidence of risks such as epidural abscess, catheter infection and bacterial colonisation

• Overall, engage in good shared decision making and risk/benefit balancing, with detailed documentation thereof
• Use ultrasound in place of nerve stimulation
• Do not use vasoconstricting adjuncts to local anaesthesia
• Consider using lower concentrations of LA in those undergoing RA for analgesic purposes, to avoid prolonged dense motor block
• Strict asepsis during block performance to reduce infection risk
• Carefully evalute risk/benefit of catheter-based techniques and, if employed, ensure close monitoring of site and limited indwelling duration