Myotoxicity of local anesthetics is equivalent in individuals with and without predisposition to malignant hyperthermia

Abstract

Purpose

Malignant hyperthermia (MH) is an inherited muscle disorder caused by abnormal elevations of intracellular calcium (Ca²⁺) in skeletal muscle. There are several reports of myotoxicity caused by local anesthetics, and the increased intracellular Ca²⁺ is considered to be an important cause. However, there is insufficient evidence regarding myotoxicity in MH-susceptible individuals when large doses of local anesthetics are administered. This study investigated the effect of MH predisposition on myotoxicity.

Methods

Human skeletal muscle samples were obtained from 22 individuals to determine susceptibility to MH, and were evaluated according to whether their Ca²⁺-induced Ca²⁺ release (CICR) rates were accelerated or not. This study was performed using surplus muscle that remained after the CICR rate test. We calculated the 50% effective concentration (EC₅₀) values of three local anesthetics, namely lidocaine, levobupivacaine, and ropivacaine using the ratiometric dye Fura-2 AM. Significance was tested using the unpaired t test.

Results

In the accelerated and unaccelerated groups, respectively, the mean ± SD of the EC₅₀ values were 1.52 ± 0.72 and 1.75 ± 0.37 mM for lidocaine (p = 0.42), 0.72 ± 0.36 and 0.79 ± 0.46 mM for levobupivacaine (p = 0.68), and 1.21 ± 0.35 and 1.62 ± 0.57 mM for ropivacaine (p = 0.06). These values were similar in individuals with and without MH predisposition.

Conclusion

The myotoxicity of local anesthetics was equivalent in individuals with and without predisposition to MH.

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Calculation algorithms for breath-by-breath alveolar gas exchange: the unknowns!

Abstract

Purpose

Several papers (algorithm papers) describe computational algorithms that assess alveolar breath-by-breath gas exchange by accounting for changes in lung gas stores. It is unclear, however, if the effects of the latter are actually considered in literature. We evaluated dissemination of algorithm papers and the relevant provided information.

Methods

The list of documents investigating exercise transients (in 1998–2017) was extracted from Scopus database. Documents citing the algorithm papers in the same period were analyzed in full text to check consistency of the relevant information provided.

Results

Less than 8% (121/1522) of documents dealing with exercise transients cited at least one algorithm paper; the paper of Beaver et al. (J Appl Physiol 51:1662–1675, 1981) was cited most often, with others being cited tenfold less. Among the documents citing the algorithm paper of Beaver et al. (J Appl Physiol 51:1662–1675, 1981) (N = 251), only 176 cited it for the application of their algorithm/s; in turn, 61% (107/176) of them stated the alveolar breath-by-breath gas exchange measurement, but only 1% (1/107) of the latter also reported the assessment of volunteers' functional residual capacity, a crucial parameter for the application of the algorithm. Information related to gas exchange was provided consistently in the methods and in the results in 1 of the 107 documents.

Conclusion

Dissemination of algorithm papers in literature investigating exercise transients is by far narrower than expected. The information provided about the actual application of gas exchange algorithms is often inadequate and/or ambiguous. Some guidelines are provided that can help to improve the quality of future publications in the field.

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Role of capillary pericytes in the integration of spontaneous Ca2+ transients in the suburothelial microvasculature in situ of the mouse bladder

The Journal of Physiology, EarlyView.


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Expression of TRPV1 channels by Cajal‐Retzius cells and layer‐specific modulation of synaptic transmission by capsaicin in the mouse hippocampus

The Journal of Physiology, EarlyView.


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Rho kinase collaborates with p21‐activated kinase to regulate actin polymerization and contraction in airway smooth muscle

The Journal of Physiology, EarlyView.


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The anatomical pathway from the mesodiencephalic junction to the inferior olive relays perioral sensory signals to the cerebellum in the mouse

The Journal of Physiology, EarlyView.


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KV1.5 channel down‐regulation in pulmonary hypertension is nothing short of MiR‐1‐aculous!

The Journal of Physiology, EarlyView.


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Increased susceptibility to cardiovascular disease in offspring born from dams of advanced maternal age

The Journal of Physiology, EarlyView.


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miR‐1 is increased in pulmonary hypertension and downregulates Kv1.5 channels in rat pulmonary arteries

The Journal of Physiology, EarlyView.


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The regularity of orthosis use and the reasons for disuse in stroke patients

This is a Retrospective descriptive study. Orthoses and walking aids are used frequently in stroke rehabilitation to facilitate ambulation. The aim was to describe the regularity of orthosis use and the reasons for disuse in stroke after discharge from inpatient rehabilitation. The study included 64 (43 men, 21 women) subacute stroke patients who had been discharged from our clinic in the last 6 months. Demographic and clinical findings, proposed orthoses and walking aids, frequency of usage for the proposed orthoses, reasons for disuse, and the ambulation levels were recorded. A total of 54 (84.4%) patients had an ankle–foot orthosis and 10 (15.6%) patients had a knee–ankle–foot orthosis. The orthosis frequency of use was every day in 38 (59.4%) patients and one to seven times a week in seven (10.9%) patients, whereas 19 (29.7%) did not use them. The reasons for orthosis disuse were finding them unnecessary in seven (27%) patients, usage difficulties in six (23%) patients, pressure sensation in five (19.2%) patients, the belief that they did not make life easier in five (19.2%) patients, lack of a suitable environment in one (3.8%) patient, orthosis wear in one (3.8%) patient, and systemic disease in one (3.8%) patient. Age, sex, residence, the disease duration, and recommended orthosis duration (how long the prescribed orthosis was used), recommended orthosis, range of motion limitation in the lower extremities, presence of spasticity, type of orthosis, and the ambulation level were not statistically significantly associated with the frequency of orthosis use (P>0.05). The only significant clinical factor for the frequency of orthosis use was the lower extremity Brunnstrom neurophysiological recovery stage (P

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Paroxysmal Sympathetic Hyperactivity and Clinical Considerations for Patients with Acquired Brain Injuries: A Narrative Review

The term "storming" has often been used colloquially to characterize brain injured patients who showed signs and symptoms of elevated heart rate, blood pressure, respiratory rate, temperature, and motor posturing. Recently, the term paroxysmal sympathetic hyperactivity (PSH) has been used as the unifying term to describe these acute episodes of elevated sympathetic hyperactivity. Various pharmaceutical and management options are available, but no single drug or protocol has been deemed superior to the others. Data on prognosis and recovery in relation to PSH are limited, but point toward poorer functional outcome and increased mortality. Overall, the phenomenon of PSH requires further research to aid rehabilitative efforts so that patients can effectively participate in therapy. A review of the literature has revealed sparse information on the management of sympathetic storming within rehabilitation facilities. This narrative review seeks to provide an up-to-date synopsis and recommendations on the management of rehabilitation inpatients with PSH. Please address all correspondence to: Brian D. Greenwald, MD, Medical Director of Center for Brain Injuries, JFK Medical Center- Johnson Rehabilitation Institute, 65 James Street, Edison, NJ, 08820. Phone: 732-321-7000 ext: 62018. Fax: 732-321-7733. Email: BGreenwald@hackensackmeridian.org There are no disclosures or conflicts of interest reported by the authors. No funding was received by the authors for this work. Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.

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