This review seeks to address 10 essential questions regarding the clinical use of local anaesthetics. Each local anaesthetic has distinctive physicochemical properties but with the same mode of action; they block voltage-gated sodium channels in the axon. Sodium channel block is brought about by a conformational change and the creation of a positive charge in the channel pore. Different local anaesthetics can reach the local anaesthetic binding site in the axon from the cytoplasmic compartment (classic hydrophilic pathway), or directly via its lipid membrane (hydrophobic pathway), or can enter via large-pore channels (alternative hydrophilic pathway). Beyond the nervous system, local anaesthetics exert beneficial effects on pain and can affect the inflammatory response and the haemostatic system. There are problems with the efficacy of local anaesthetics in the presence of local inflammation, and with significant intravascular toxicity, which can be fatal. But when preventive measures are taken, the incidence of cardiac arrest is low. Intralipid has been proposed to treat systemic local anaesthetic overdose and has been enthusiastically adopted worldwide, even though the mechanism of action is incompletely understood. Intralipid is an aid to the management of local anaesthetic toxicity rather than an antidote and meticulous conduct of regional anaesthesia remains paramount. All local anaesthetics are toxic, in a dose- and time-dependent manner, on virtually all tissues, including nerves and muscles. The question of whether local anaesthetics protect against perioperative tumour progression cannot be answered at this moment, and results from clinical (retrospective) studies are equivocal. Future areas of interest will be the design of new subtype-specific sodium channel blockers, but as we look forward, older local anaesthetics such as 2-chloroprocaine are being reintroduced into the clinical setting. Multimodal perineural analgesia and liposomal bupivacaine may replace catheter techniques for some indications.

A high prevalence of delirium was noted in the PICU, and several perioperative risk factors were identified. Our data may be a base for development of strategies to prevent and treat postoperative delirium in children.

In a rodent type II DM model, nerves have increased sensitivity for short-acting local anaesthetics without adjuvants in vivo, as evidenced by prolonged block duration. This sensitivity appears to increase with the progression of neuropathy. Our results do not support the hypothesis that neuropathy due to type II DM increases the risk of nerve injury after nerve block.

Background: Neck pain is a frequent reason for seeking medical advice. Neuroanatomical findings suggest a close connection between the pharynx and the trapezius region. Irritation of the pharynx may induce tenderness of this area. Specific tender points, called neck reflex points (NRPs), can be identified here with high reproducibility. We hypothesized that therapeutic local anesthesia (TLA; or neural therapy, NT) in the pharyngeal region can reduce tenderness in patients with therapy-resistant neck pain. Patients and Methods: 17 consecutive female patients with chronic cervical pain and positive trapezius NRPs received bilateral injections of 0.5 ml 1% procaine into the palatine velum. The NRPs were assessed using a 3-level pain index (PI = 0, 1, or 2) before and 3-5 min after each injection. Results: We found a significant reduction in tenderness of the NRP of the trapezius region (NRP C7) immediately after TLA/NT. 30 positive NRPs were found before therapy and only 13 after therapy (p < 0.01). The average PI of the NRP C7 was 1.24 ± 0.77 before and 0.35 ± 0.59 after therapy (right side), and 1.34 ± 0.59 before and 0.59 ± 0.69 after therapy (left side). The pre- and post-therapy PI values were significantly different on both the right and left sides of the trapezius region (p < 0.01). No adverse effects were observed. Conclusions: Pharyngeal irritation may induce and maintain therapy-resistant cervical pain in patients with chronic pharyngeal disease. These patients could benefit from remote TLA/NT injections in the pharyngeal region.

Background Clinical and experimental data show that peripheral nerve blocks last longer in the presence of diabetic neuropathy. This may occur because diabetic nerve fibers are more sensitive to local anesthetics or because the local anesthetic concentration decreases more slowly in the diabetic nerve. The aim of this study was to investigate both hypotheses in a rodent model of neuropathy secondary to type 2 diabetes. Methods We performed a series of sciatic nerve block experiments in 25 Zucker Diabetic Fatty rats aged 20 weeks with a neuropathy component confirmed by neurophysiology and control rats. We determined in vivo the minimum local anesthetic dose of lidocaine for sciatic nerve block. To investigate the pharmacokinetic hypothesis, we determined concentrations of radiolabeled (14C) lidocaine up to 90 min after administration. Last, dorsal root ganglia were excised for patch clamp measurements of sodium channel activity. Results First, in vivo minimum local anesthetic dose of lidocaine for sciatic nerve motor block was significantly lower in diabetic (0.9%) as compared to control rats (1.4%). Second, at 60 min after nerve block, intraneural lidocaine was higher in the diabetic animals. Third, single cell measurements showed a lower inhibitory concentration of lidocaine for blocking sodium currents in neuropathic as compared to control neurons. Conclusions We demonstrate increased sensitivity of the diabetic neuropathic nerve toward local anesthetics, and prolonged residence time of local anesthetics in the diabetic neuropathic nerve. In this rodent model of neuropathy, both pharmacodynamic and pharmacokinetic mechanisms contribute to prolonged nerve block duration.

Lidocaine modulates muscarinic m1 and m3 receptors in a time- and Gαq-dependent manner, but this is masked by enhanced PKC activity. The biphasic time course may be due to interactions of LAs with an extracellular receptor domain, modulated by PKC activity. Prolonged exposure to LAs may not benefit pulmonary function, but may positively affect postoperative cognitive function.

Local anesthetics significantly attenuated Gαq-protein-mediated neutrophil priming. The most potent inhibition was achieved by ester compounds, inversely correlated with their octanol-buffer coefficient, and enhanced by permanent charges within the LA molecule. No correlation to their potency of blocking sodium channels was found.

Background Patients with hepatocellular carcinoma (HCC) are selected for transplantation if they have a low tumour burden and low risk of recurrence. The morphometric Milan criteria have been the cornerstone for patient selection, but dynamic morphological and biological tumour characteristics surfaced as an encouraging tool to refine the selection of patients with HCC and to support the expansion of the Milan criteria. The outcomes of the most prevalent models that select patients with HCC for liver transplantation were analysed in this study, which aimed to identify the selection model that offered the best recurrence-free and overall survival after transplantation. Methods Studies that compared Milan, University of California San Francisco (UCSF), up-to-seven (UPTS), alpha-fetoprotein (AFP), and MetroTicket 2.0 (MT2) models were included. One-year, 3-year, and 5-year recurrence-free and overall survival rates of patients selected for transplantation using different models were analysed. Results A total of 60 850 adult patients with HCC selected for liver transplantation using Milan, UCSF, UPTS, AFP, or MT2 criteria were included. Patients selected for transplantation using the MT2 model had the highest 1-, 3-, and 5-year recurrence-free survival. In addition, patients selected for transplantation using MT2 criteria had the best 1- and 3-year overall survival, whereas patients selected for transplantation using the Milan criteria had the best 5-year overall survival rates. Conclusion The MT2 model offered the best post-transplant outcomes in patients with HCC, highlighting the importance of considering tumour morphology and biology when selecting patients with HCC for liver transplantation.