Articles: anesthetics.
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Local anesthetics block nerve impulse propagation by occluding transmembrane sodium channels, so preventing depolarization. First, the uncharged lipid-soluble anesthetic base pentrates the membrane; then the positively charged cation binds to anionic components of the sodium channel's internal axoplasmic mouth. ⋯ The cation-base concentration ration is critical to optimal neural blockade. If there is too little base, few anesthetic molecules will penetrate to the neural target; if too little cation, few sodium channels will be plugged.
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Anesth Analg (Paris) · Sep 1977
[Anesthesia and resuscitation in surgery for aseptic osteonecrosis in patients with renal transplants].
Aseptic osteonecrosis following renal transplantation occurs in about 20 p. 100 of cases and entails important functional consequences. 16 patients with kidney transplant and 4 patients on chronic dialysis because of previous graft rejection underwent 27 orthopaedic operations, 8 of which being hip arthroplasties. During and after the procedure the anesthesiologist had to manage with drug interaction, coagulation disorders, blood compatibility problems etc... Despite poor general condition of patients and the risk of infectious complications linked to the never interrupted immunosupressive treatment, the surgical results of our serial were good.
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The physical status of the patient (sex, age, weight, height, and underlying disease) has been thought to influence the dosage of local anesthetic drugs that can be injected without causing a systemic toxic reaction, but this belief is not supported by statistically significant data. Furthermore, previous studies of plasma levels of bupivacaine and mepivacaine showed no correlation between dosage and physical status, even when maximum dosages recommended by pharmaceutical companies were exceeded. This study of 9,287 regional blocks, using the statistical tests of multiple regression and chi square, substantiates that the occurrence of systemic toxic reactions in adults does not correlate with dosages and/or physical status of the patient when 400 mg or less of bupivacaine, 450 mg or less of etidocaine, or 500 mg or less of mepivacaine is used. Therefore, the study questions the maximum dosages established for certain local anesthetic drugs, as well as the method by which such dosages were established.