Anaesthesia
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Cancer accounts for millions of deaths globally each year, predominantly due to recurrence and metastatic disease. The majority of patients with primary solid organ cancers require surgery, however, some degree of tumour dissemination related to surgery is inevitable. The surgical stress response and associated immunosuppression, pain, inflammation, tissue hypoxia and angiogenesis have all been implicated in promoting tumour survival, proliferation and recurrence. ⋯ Randomised controlled trials on the long-term oncological outcomes of regional anaesthesia in other tumour types are ongoing. The focus on how peri-operative interventions, especially regional anaesthesia, during cancer resection surgery, may enhance short-term recovery and perhaps influence long-term outcome has spawned the global emergence of the subspecialty of onco-anaesthesia. This review aims to discuss the most recent evidence on the use of regional anaesthesia in cancer surgery and the significance of its role in onco-anaesthesia.
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Effective prevention of chronic postoperative pain is an important clinical goal, informed by a growing body of studies. Peri-operative regional anaesthesia remains one of the most important tools in the multimodal analgesic toolbox, blocking injury-induced activation and sensitisation of both the peripheral and central nervous system. We review the definition and taxonomy of chronic postoperative pain, its mechanistic basis and the most recent evidence for the preventative potential of multimodal analgesia, with a special focus on regional anaesthesia. While regional anaesthesia targets several important aspects of the mechanistic pathway leading to chronic postoperative pain, evidence for its efficacy is still mixed, possibly owing to the heterogeneity of risk profiles within the surgical patient, but also to variation in techniques and medications reported in the literature.
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The risks of regional anaesthesia relate primarily to the technical nature of the procedure, chief among them being neurological. While rare, the direct relationship between nerve damage and the procedure itself means that patients need to be aware of this complication when consent is sought. In order to give valid consent, a patient must be informed. ⋯ Patients also have biases, and doctors must be aware of these in order to best target their provision of information. Careful use of language and employing adjuncts such as information leaflets and visual aids can help to maximise the individual's autonomy. Particular care must be taken in special situations such as where patients have capacity issues or time is limited by the emergency nature of the intervention.
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Diabetes is the most common metabolic condition worldwide and about 20% of surgical patients will have this condition. It is a major risk-factor for worse outcomes after surgery including mortality; infective and non-infective complications; and increased length of stay. ⋯ The aim of this review is to explore in detail the various potential advantages and disadvantages of regional anaesthesia in patients with diabetes. This, in turn, will allow practitioners to undertake more informed shared decision-making and potentially modify their anaesthetic technique for patients with diabetes.
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Review
The role of peripheral nerve stimulation in the era of ultrasound-guided regional anaesthesia.
With the widespread use of ultrasound for localising nerves during peripheral nerve blockade, the value of electrical nerve stimulation of evoked motor responses has been questioned. Studies continue to show that, compared with nerve stimulation, ultrasound guidance alone leads to: significantly improved block success; decreased need for rescue analgesia; decreased procedural pain; and lower rates of vascular puncture. Nerve stimulation combined with ultrasound does also not appear to improve block success rates, apart from those blocks where the nerves are challenging to view, such as the obturator nerve. ⋯ Nerve stimulation can serve as a monitor against needle-nerve contact and may be useful in avoiding nerves that are in the needle trajectory during specific ultrasound guided techniques. Nerve stimulation is also a useful adjunct in teaching novices ultrasound-guided regional anaesthesia, especially when the position and or appearance of nerves may be variable. In this review, the changing role of nerve stimulation in contemporary regional anaesthetic practice is presented and discussed.