Anaesthesia
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Unintended accidental awareness during general anaesthesia represents failure of successful anaesthesia, and so has been the subject of numerous studies during the past decades. As return to consciousness is both difficult to describe and identify, the reported incidence rates vary widely. Similarly, a wide range of techniques have been employed to identify cases of accidental awareness. ⋯ Among patients who experience accidental awareness and can later remember details of their experience, the consequences are better known. In particular, when awareness occurs in a patient who has been given neuromuscular blocking agents, it may result in serious sequelae such as symptoms of post-traumatic stress disorder and a permanent aversion to surgery and anaesthesia, and is feared by patients and anaesthetists. In this article, the published literature on the incidence, consequences and management of accidental awareness under general anaesthesia with subsequent recall will be reviewed.
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Observational Study
Can point-of-care ultrasound predict spinal hypotension during caesarean section? A prospective observational study.
Spinal anaesthesia for elective caesarean section is associated with maternal hypotension, secondary to alteration of sympathetic tone and hypovolemia, in up to 70% of cases. Measurement of the subaortic variation in the velocity time integral (VTI) after passive leg raising allows prediction of fluid responsiveness. Our objective, in this prospective single-centre observational study, was to assess the ability of change in VTI after 45° passive leg raising to predict hypotension after spinal anaesthesia. ⋯ Seventeen women had a change in VTI with leg elevation ≤ 8%, which was predictive for not developing hypotension, and 11 had a change ≥ 21%, predictive for hypotension. The grey zone between 8% and 21%, with inconclusive values, included 12 women. We suggest that cardiac ultrasound provides characterisation of the risk of hypotension following spinal anaesthesia at elective caesarean section, and therefore may allow individualised strategies for prevention and management.
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Review
Pharmacokinetics and pharmacodynamics of sublingual sufentanil for postoperative pain management.
Achieving successful treatment of postoperative pain remains a challenge. Recently, a sufentanil sublingual tablet system has been developed for treatment of moderate-to-severe postoperative pain. The phenylpiperidine sufentanil is a potent analgesic that rapidly crosses the blood-brain barrier and selectively activates central μ-opioid receptors. ⋯ We conclude that sufentanil is suited for the transmucosal route due to its pharmacokinetic profile, including rapid onset, absence of active metabolites and low tissue accumulation. The efficacy and safety of the sufentanil sublingual tablet system has been shown in over 600 patients in a limited set of studies; further independent studies are required to determine the position of the system among other forms of postoperative pain treatment. We conclude that the sublingual sufentanil tablet system allows effective pain relief, and allows patients to control their own pain relief and early postoperative mobility.
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Surgery and anaesthesia might affect cognition in middle-aged people without existing cognitive dysfunction. We measured memory and executive function in 964 participants, mean age 54 years, and again four years later, by when 312 participants had had surgery and 652 participants had not. Surgery between tests was associated with a decline in immediate memory by one point (out of a maximum of 30), p = 0.013: memory became abnormal in 77 out of 670 participants with initially normal memory, 21 out of 114 (18%) of whom had had surgery compared with 56 out of 556 (10%) of those who had not, p = 0.02. ⋯ Working memory decline was also associated with longer cumulative operations, beta coefficient (SE) -0.01 (0.00), p = 0.028. A reduction in cognitive speed and flexibility was associated with worse ASA physical status, beta coefficient (SE) 0.55 (0.22) and 0.37 (0.17) for ASA 1 and 2 vs. 3, p = 0.035. However, a decline in working memory was associated with better ASA physical status, beta coefficient (SE) -0.48 (0.21) for ASA 1 vs. 3, p = 0.01.
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In this article, we will discuss the pathophysiology of peripheral nerve injury in anaesthetic practice, including factors which increase the susceptibility of nerves to damage. We will describe a practical and evidence-based approach to the management of suspected peripheral nerve injury and will go on to discuss major nerve injury patterns relating to intra-operative positioning and to peripheral nerve blockade. We will review the evidence surrounding particular strategies to reduce the incidence of peripheral nerve injury during nerve blockade, including nerve localisation methods, timing of blocks, needle techniques and design, injection pressure-monitoring and local anaesthetic and adjunct choice.