Updates in our understanding of local anaesthetic systemic toxicity: a narrative review

Despite advances in clinical practice, local anaesthetic systemic toxicity continues to occur with the therapeutic use of local anaesthesia. Patterns of presentation have evolved over recent years due in part to the increasing use of ultrasound which has been demonstrated to reduce risk. Onset of toxicity is increasingly delayed, a greater proportion of clinical reports are secondary to fascial plane blocks, and cases are increasing where non-anaesthetist providers are involved. The evolving clinical context presents a challenge for diagnosis and requires education of all physicians, nurses and allied health professionals about these changing patterns and risks. This review discusses: mechanisms; prevention; diagnosis; and treatment of local anaesthetic systemic toxicity. The local anaesthetic and dose used, site of injection and block conduct and technique are all important determinants of local anaesthetic systemic toxicity, as are various patient factors. Risk mitigation is discussed including the care of at-risk groups, such as: those at the extremes of age; patients with cardiac, hepatic and specific metabolic diseases; and those who are pregnant. Advances in the changing clinical landscape with novel applications and settings for the use of local anaesthesia are also described. Finally, we signpost future directions to potentially improve the management of local anaesthetic systemic toxicity. The utility of local anaesthetics remains unquestionable in clinical practice, and thus maximising the safe and appropriate use of these drugs should translate to improvements in patient care.

Evaluation of a hospital-wide vancomycin-dosing nomogram in patients with continuous-flow left ventricular assist devices

INTRODUCTION

Hemodynamic derangements due to heart failure are associated with alterations in pharmacokinetics. Although use of mechanical circulatory support mitigates such derangements, little evidence is available regarding pharmacokinetics in patients with LVADs. A previous pharmacokinetic analysis of vancomycin among patients with LVADs observed a reduced volume of distribution and clearance compared with estimates based on population kinetics.

METHODS

A total of 28 adult patients with LVADs hospitalized between January 2014 and May 2018 who received vancomycin through a pharmacist dosing consult were included. Internal medicine patients without heart failure receiving vancomycin were enrolled in a 2:1 fashion to make a control group. Exclusion criteria were unstable renal function, ESRD, acute decompensation, cardiac surgery within the preceding 5 days, or weight >110 kg.

RESULTS

No difference was observed in the proportion achieving goal trough (64% of LVAD patients vs 71% control patients, p = 0.50). However, mean trough was significantly higher among LVAD patients (23.4 mg/L vs 17.7 mg/L, p = 0.017). Furthermore, there was a significant difference in the distribution of trough levels (p = 0.025) with LVAD patients being more likely to attain levels >25 mg/L (32% vs 14%) and less likely to have troughs <10 mg/L (4% vs 14%). A numerically greater number of LVAD patients experienced nephrotoxicity but this did not reach statistical significance (32% vs 18%, p = 0.14).

CONCLUSION

The use of vancomycin in LVAD patients may result in higher trough levels when compared to internal medicine patients. Increased monitoring or conservative dosing may be warranted to improve safety and efficacy.

Local Anesthetic Toxicity in the Geriatric Population

This article provides a concise overview of local anesthetic systemic toxicity, its history, mechanisms, risk factors, prevention, clinical presentation, and treatment, with a special emphasis on issues specific to the geriatric population. The authors used MEDLINE, Scopus, and Google Scholar to search for original research articles (human and animal studies), registries data, case reports, review articles, and pertinent online publications using the combinations of the following search terms: local anesthetics, local anesthetic systemic toxicity, intralipid, lipid emulsion, Exparel, ultrasound-guidance, regional anesthesia, lidocaine, bupivacaine, ropivacaine, cocaine, procaine, tetracaine, levobupivacaine, liposomal bupivacaine, lignocaine. Local anesthetic systemic toxicity continues to occur despite the use of putatively less cardiotoxic formulations of local anesthetics and more common use of ultrasound guidance. The elderly appear to be at a disproportionately increased risk for toxicity owing to the presence of relevant comorbidities and decreased muscle mass. Examination of recent case reports involving patients over the age of 65 years demonstrates that inadvertent overdosing is responsible for some cases of local anesthetic systemic toxicity. Elderly patients are at increased risk of local anesthetic systemic toxicity. When considering use of local anesthetics in older patients, special attention should be paid to the presence of systemic disease and muscle wasting. The safety of regional anesthesia and multi-modal analgesia among these at-risk patients will be improved by educating physicians and staff to recognize and manage local anesthetic systemic toxicity.

[Specifics of diagnosis and treatment of diabetic polyneuropathy in elderly patients]

AIM

To study the specifics of diagnosis and treatment of diabetic polyneuropathy in elderly patients.

MATERIAL AND METHODS

Forty-two patients (22 men and 20 women, aged from 65 to 75 years) with diabetes mellitus type 2 and diabetic polyneuropathy were studied using the following psychometric scales: the Michigan Neuropathy Screening Instrument (MNSI), Neurological symptoms scale (NSS), Neuropathy Disability Score (NDS), the Numerical Rating Scale (NRS), Kaplan-Feinstein index (KFI), the Covi Anxiety Scale (COVI), the Recovery Locus of Control Scale (RLOC). Patients were divided into group 1 (n=24) treated with neuromultivit injections, along with standard treatment, and group 2 (n=18), which received standard treatment only. Patients were examined at baseline and one month after treatment.

RESULTS

In elderly patients, diabetic distal symmetric sensorimotor polyneuropathy of moderate severity was comorbid mostly with cardio-vascular disease. Pain syndrome was associated with anxiety and significant direct correlation between anxiety and pain intensity was found. The level of motivation towards recovery was significantly lower and correlated with COVI scores.

CONCLUSION

Injections of neuromultivit decrease the intensity of pain, improve the emotional state and increase the level of motivation towards recovery.