Addition of bicarbonate to plain bupivacaine does not significantly alter the onset or duration of plexus anesthesia.

Background And Objectives: In an effort to elucidate further the effect of alkalinization of bupivacaine on its anesthetic effect, a study was undertaken using alkalinized and non-alkalinized bupivacaine for lumbar plexus block and comparing the results with those obtained previously with brachial plexus block.

Methods: Thirty consenting adult patients about to undergo lower extremity surgery under regional anesthesia were selected for the study. All of the patients received an inguinal paravascular lumbar plexus block ("3-in-1 block"), along with a sciatic block to allow the anticipated surgery to be carried out.

The rationale for cementless revision total hip replacement with contemporary technology.

Undoubtedly, the number of revisions for failed cemented total hip arthroplasties will increase over time based on current survival statistics. Although contemporary cementing techniques may improve the outcome of some procedures, long-term results of cemented revisions are less than ideal. Poor bone quality with cortical deficiencies and endosteal sclerosis make long-term stability and implant survival less likely with cemented techniques.

Cardiac electrophysiologic effects of articaine compared with bupivacaine and lidocaine.

Articaine is a local anesthetic structurally different from lidocaine and bupivacaine in that it contains a thiophene ring. We compared its cardiodepressant effects with those of lidocaine and bupivacaine in a randomized, blinded study using the isolated rabbit heart preparation. The hearts were removed quickly from thiamylal anesthetized/killed animals.

Effect of progesterone on the cardiac electrophysiologic alterations produced by ropivacaine and bupivacaine.

Bupivacaine-induced cardiotoxicity is enhanced in pregnant laboratory animals and in progesterone-pretreated isolated cardiac tissues. Ropivacaine is a new local anesthetic chemically related to bupivacaine. Although clinically equipotent with bupivacaine, ropivacaine is less cardiodepressant.

Chronotropic and inotropic effects of ropivacaine, bupivacaine, and lidocaine in the spontaneously beating and electrically paced isolated, perfused rabbit heart.

Background And Objectives: The purpose of this study was to compare the inotropic and chronotropic effects of ropivacaine, bupivacaine, and lidocaine in an isolated, spontaneously beating rabbit heart preparation. The ability to electrically pace the heart in the presence of local anesthetic also was examined.

Methods: Hearts were perfused with Krebs-Henseleit solution, then exposed to ropivacaine or bupivacaine at 1, 6, or 13 micrograms/ml or lidocaine at 6, 20, or 40 micrograms/ml (n = 6, each concentration).

Effects of progesterone on the cardiac electrophysiologic action of bupivacaine and lidocaine.

Pregnancy is accompanied by an increased cardiac and neural sensitivity to some local anesthetic agents such as bupivacaine. The current study was initiated to investigate the relationship between increased progesterone concentrations and the electrophysiologic effects of bupivacaine, and lidocaine in isolated Purkinje fiber (PF)-ventricular muscle (VM) preparations. Twenty-four oophorectomized female white rabbits were killed after receiving 30 mg.

Effect of ropivacaine and bupivacaine on uterine blood flow in pregnant ewes.

The effects of ropivacaine, a new amide local anesthetic, on uterine blood flow and fetal well-being were compared with those of bupivacaine in 10 chronically instrumented pregnant ewes. In random sequence, animals received two intravenous infusions of each drug. The low infusion rate regimens were chosen to result in clinically relevant maternal plasma concentrations of local anesthetics, whereas the more rapid rates of infusions were given to assess the safety of higher maternal drug concentrations.

The effects of epinephrine on the anesthetic and hemodynamic properties of ropivacaine and bupivacaine after epidural administration in the dog.

Ropivacaine is a new local anesthetic that is chemically related to mepivacaine and bupivacaine. Previous laboratory studies have demonstrated that ropivacaine possesses an anesthetic profile similar to that of bupivacaine and has less arrhythmogenic potential. The current study was initiated to compare the hemodynamic and anesthetic effects of epidurally administered 0.

Treatment of acute systemic toxicity after the rapid intravenous injection of ropivacaine and bupivacaine in the conscious dog.

Two groups of six beagle dogs received rapid intravenous (IV) injections of ropivacaine or bupivacaine on two occasions in a blinded random fashion. Initially, a dose sufficient to cause convulsions (CD) was given followed by twice the CD (2 x CD), which was administered 48 h later. The CD of bupivacaine (4.

Systemic toxicity of ropivacaine during ovine pregnancy.

Ropivacaine is a new amide local anesthetic structurally related to bupivacaine and mepivacaine. Its potency and duration of action are similar to those of bupivacaine but its therapeutic index may be greater. Since pregnancy enhances the cardiotoxicity of bupivacaine, the current study was devised to compare the toxicity of ropivacaine in chronically instrumented nonpregnant and pregnant ewes during continuous intravenous infusion of the drug at the rate of 0.

Acute progesterone treatment has no effect on bupivacaine-induced conduction blockade in the isolated rabbit vagus nerve.

Pregnancy decreases anesthetic requirements during regional anesthesia. Using an in vitro animal model, this study attempts to elucidate the mechanism of hormonal effects on nerve conduction in desheathed rabbit vagus nerve. The acute effects of progesterone administration on neural blockade induced by bupivacaine were investigated in terms of changes in compound action potentials of A, B, and C fibers.

The torsion meter: a critical review.

The purpose of this study was to determine how effectively the torsion meter measures vertebral rotation. Nine thoracic vertebrae from three disarticulated spines were individually rotated through an arc of 0-60 degrees and measured with a torsion meter by three investigators. One hundred forty-four errors were made in the 351 measurements, of which greater than 92% were within +/- 5 degrees.

Pregnancy does not alter lidocaine toxicity.

Pregnant sheep are more vulnerable to the toxic effects of bupivacaine, a potent local anesthetic, than are nonpregnant sheep. In contrast, ovine pregnancy does not enhance the toxicity of mepivacaine, a drug with properties similar to lidocaine. We studied the central nervous and cardiovascular toxicity of lidocaine in pregnant sheep receiving a continuous intravenous drug infusion at the rate of 2 mg/kg/min and compared our results with data previously obtained in nonpregnant ewes.

Pharmacokinetics of ropivacaine in nonpregnant and pregnant ewes.

The pharmacokinetics of ropivacaine were studied in chronically instrumented nonpregnant and pregnant ewes. On the day of study, the urinary bladder was catheterized. Ropivacaine (2.

Cardiac electrophysiologic properties of bupivacaine and lidocaine compared with those of ropivacaine, a new amide local anesthetic.

Ropivacaine is a new amino-amide local anesthetic whose anesthetic profile appears similar to that of bupivacaine. Moreover, in intact animals ropivacaine was reportedly less arrhythmogenic than bupivacaine. These experiments evaluated the cardiac transmembrane electrophysiologic effects of ropivacaine compared with those of lidocaine and bupivacaine in an isolated rabbit Purkinje fiberventricular muscle preparation.

A new local anesthetic, ropivacaine. Its epidural effects in humans.

The current study was initiated to evaluate the epidural anesthetic properties of 0.5%, 0.75%, and 1.

Comparative systemic toxicity of convulsant and supraconvulsant doses of intravenous ropivacaine, bupivacaine, and lidocaine in the conscious dog.

This study evaluated the systemic toxicity, arrhythmogenicity, and mode of death of convulsant and supraconvulsant doses of lidocaine, bupivacaine, and ropivacaine. Experiments in awake dogs were designed to mimic the clinical situation of an accidental intravenous (IV) injection of local anesthetics. On the first experimental day, lidocaine (8 mg.

Adverse effects of maternally administered lidocaine on the asphyxiated preterm fetal lamb.

Lidocaine was infused at a constant rate of 0.1 mg.kg-1.

Comparison of bupivacaine- and ropivacaine-induced conduction blockade in the isolated rabbit vagus nerve.

Ropivacaine (LEA-103) is a new amino-amide local anesthetic agent the chemical structure and anesthetic properties of which are similar to bupivacaine. Preliminary studies in animals indicate that the CNS toxicities of ropivacaine and bupivacaine are similar, but that ropivacaine may have less arrhythmogenic effects than bupivacaine. The current study arrhythmogenic effects than bupivacaine.

Does pregnancy alter the systemic toxicity of local anesthetics?

The toxicity of mepivacaine in chronically instrumented nonpregnant and pregnant sheep was evaluated, and compared with data from previous studies of the toxicity of other local anesthetics. Thirteen preparations were studied, seven nonpregnant (NP) and six pregnant (P). Mepivacaine 2 mg.

Rationale for spinal anesthesia.

Spinal anesthesia is probably the most widely used form of regional anesthesia today. A number of clinical studies suggest that spinal anesthesia may be superior to general or epidural anesthesia for certain patients and for certain surgical procedures. The endocrine-metabolic response to surgery appears to be blunted when spinal anesthesia is employed compared to the response during general anesthesia.

Hypertonic saline reverses bupivacaine-induced depression of rabbit Purkinje fiber depolarization Vmax.

The present study describes the effect of a hypertonic increase in sodium chloride concentration on electrophysiological parameters. Membrane depolarization was recorded from rabbit Purkinje fibers superfused with warm, aerated Tyrode solution. An amount of 5% NaCl above that in normal Tyrode solution (HyNaCl, 344 mOsm) was added to the bathing medium for 30 min, significantly increasing the maximal rate of depolarization (Vmax +15% vs -7% for control), with minor effects on other parameters.