Regional anesthesia for orthopedic procedures:What orthopedic surgeons need to know

Regional anesthesia is an integral component of successful orthopedic surgery.Neuraxial anesthesia is commonly used for surgical anesthesia while peripheral nerve blocks are often used for postoperative analgesia.Patient evaluation for regional anesthesia should include neurological,pulmonary,cardiovascular,and hematological assessments.Neuraxial blocks include spinal,epidural,and combined spinal epidural.Upper extremity peripheral nerve blocks include interscalene,supraclavicular,infraclavicular,and axillary.Lower extremity peripheral nerve blocks include femoral nerve block,saphenous nerve block,sciatic nerve block,iPACK block,ankle block and lumbar plexus block.The choice of regional anesthesia is a unanimous decision made by the surgeon,the anesthesiologist,and the patient based on a risk-benefit assessment.The choice of the regional block depends on patient cooperation,patient positing,operative structures,operative manipulation,tourniquet use and the impact of postoperative motor blockade on initiation of physical therapy.Regional anesthesia is safe but has an inherent risk of failure and a relatively low incidence of complications such as local anesthetic systemic toxicity(LAST),nerve injury,falls,hematoma,infection and allergic reactions.Ultrasound should be used for regional anesthesia procedures to improve the efficacy and minimize complications.LAST treatment guidelines and rescue medications(intralipid)should be readily available during the regional anesthesia administration.

Evaluation of toxicity profiles of rare earth elements salts(lanthanides)

The presented study aims to extend the knowledge of toxicological profile of rare earth elements salts(REEs).The basal toxicity test performed comprised assessment of cytotoxicity(3 T3 Balb/c Neutral Red Uptake Test)that allows for calculation of LD50(rats)on the basis of the concentration which leads to a50%reduction in cell growth(IC50).Environmental toxicity was addressed by the Tubifex tubifex(T.t.)express test.The in vitro skin irritation(OECD TG 439)and skin corrosion tests(OECD TG 431)utilizing the 3 D in vitro reconstructed human epidermal model EpiDerm(MatTek IVSL,SK)were used for assessment of skin irritation and corrosion potential hazard of REEs.Mutagenic effects were determined using the bacterial reverse mutation assay(Ames Test)on 5 Salmonella typhimurium strains with and without metabolic activation(OECD TG 471).Endocrine disruption was evaluated by means of a yeastbased assay YES/YAS(Xenometrix,CH).Skin sensitization was assessed using the LuSens assay,based on a genetically modified human keratinocyte cell line(OECD TG 442 D).The tested REEs have no potential of mutagenicity or skin sensitization,exhibit very weak endocrine disruption potential and only exceptional local irritation/corrosion effects for thulium(Ⅲ)chloride anhydrous,but have acute and chronic toxic effects on the aquatic environment.

Effects of mixture of lidocaine and ropivacaine at different concentrations on the central nervous system and cardiovascular toxicity in rats

Background Lidocaine and ropivacaine are often combined in clinical practice to obtain a rapid onset and a prolonged duration of action. However, the systemic toxicity of their mixture at different concentrations is unclear. This study aimed to compare the systemic toxicity of the mixture of ropivacaine and lidocaine at different concentrations when administered intravenously in rats. Methods Forty-eJght male WJstar rats were randomly divided into 4 groups （n=12 each）： 0.5% ropJvacaine （group Ⅰ）; 1.0% ropivacaine and 1.0% lidocaine mixture （group Ⅱ）; 1.0% ropivacaine and 2.0% lidocaine mixture （group Ⅲ）; and 1.0% lidocaine （group Ⅳ）. Local anesthetics were infused at a constant rate until cardiac arrest. Electrocardiogram, electroencephalogram and arterial blood pressure were continuously monitored. The onset of toxic manifestations （seizure, dysrhythmia, and cardiac arrest） was recorded, and then the doses of local anesthetics were calculated. Arterial blood samples were drawn for the determination of local anesthetics concentrations by high-performance liquid chromatography. Results The onset of dysrhythmia was later significantly in group IV than in group Ⅰ, group Ⅱ, and group Ⅲ （P 〈0.01）, but there was no significant difference in these groups （P 〉0.05）. The onset of seizure, cardiac arrest in group Ⅰ （（9.2±1.0） min, （37.0±3.0） min） was similar to that in group Ⅱ（（9.1±0.9） min, （35.0±4.0） min） （P 〉0.05）, but both were later in group Ⅲ （（7.5±0.7） min, （28.0±3.0） min） （P 〈0.05）. The onset of each toxic manifestation was significantly later in group Ⅳ than in group Ⅰ （P 〈0.01）. The plasma concentrations of the lidocaine-alone group at the onset of dysrhythmia （DYS）, cardiac arrest （CA） （（41.2±6.8） min, （59.0±9.0） min） were higher than those of the ropivacaine alone group （（20.5±3.8） min, （38.0±8.0） min） （P 〈0.05）. The plasma concentrations of ropivacaine inducing toxic manifestation were not significantly different among groups Ⅰ, Ⅱ, and Ⅲ（P 〉0.05）. Conclusions The systemic toxicity of the mixture of 1.0% ropivacaine and 2.0% lidocaine is the greatest while that of 1.0% lidocaine is the least. However, the systemic toxicity of the mixture of 1.0% ropivacaine and 1.0% lidocaine is similar to that of 0.5% ropivacaine alone.