The action of local anesthetics, containing a tertiary nitrogen, on mammalian nonmyelinated fibers of the rabbit’s vagus nerve has been analyzed to determine whether the uncharged or the positively charged form of these compounds is responsible for their ability to block impulse conduction. The compounds studied were dibucaine, tetracaine, chlorpromazine, imipramine, and procaine. Impulse condu...

we present a case of unexpectedly prolonged motor and sensory block following a successful single injection ultrasound – guided infraclavicular block with bupivacaine (0.25%) and dexamethasone (8 mg). ultrasound guidance and safety measurement such as injection of the local anaesthetic at a slow rate and verifying that usual resistance was felt throughout the injection, has been applied. it too...

U NILATERAL diaphragm paralysis after interscalene nerve block can result in respiratory disturbances that may have a substantial impact on quality of life and increased prevalence of respiratory infections. Several reports have estimated the incidence of transient diaphragm paralysis after routine interscalene blocks for shoulder surgery to be 100%, 3 however, with modified local anesthetic do...

The scope of ultrasound imaging guidance for regional anesthesia is growing rapidly. Preliminary data, although limited, suggest that ultrasound can improve block success rate and decrease complications. In this review, we describe the basic principles of ultrasound scanning and needling techniques for nerve blocks, highlight some of the data on clinical outcome, discuss specific limitations of...

The introduction of nerve stimulation as a method of nerve localization sparked a new beginning in regional anesthesia. It was an epochal development akin to the utilization of ultrasound in more recent times. Many experts now consider ultrasound-guided peripheral nerve blockade to be more efficient, less painful, and more successful than landmark and nerve stimulation techniques. However, inad...

The practice of regional anaesthesia is rapidly changing with the introduction of ultrasound into the working domain of the anaesthesiologist. New techniques are being pioneered. Among the recent techniques, notable are the truncal blocks, for example, the transversus abdominis plane block, rectus sheath block, hernia block and quadratus lumborum block in the abdomen and the pectoral nerves (Pe...

Ankle blocks are routinely indicated for surgical anesthesia and postoperative analgesia of procedures involving the foot. Traditionally, ankle blocks have been performed by relying on landmark identification of nerves. The literature regarding the performance and efficacy of ankle blocks is inconsistent. This can be attributed to several variables, such as provider technique, differences in pa...

This study used the Frankenhaeuser-Huxley axonal model to analyze the effects of non-symmetric waveforms on conduction block of myelinated axons induced by high-frequency (10-300 kHz) biphasic electrical stimulation. The results predict a monotonic relationship between block threshold and stimulation frequency for symmetric waveform and a non-monotonic relationship for non-symmetric waveforms. ...

Ultrasound-guided regional anesthesia (UGRA) has increased in popularity over the past 5 years. This interest is reflected by the plethora of publications devoted to technique development, as well as randomized and controlled trials. Despite the excitement around ultrasonography, skeptics argue that there is a lack of evidence-based medicine to support the unequivocal adoption of UGRA as a "sta...

Minimally invasive applications of thermal and mechanical energy to selective areas of the human anatomy have led to significant advances in treatment of and recovery from typical surgical interventions. Image-guided focused ultrasound allows energy to be deposited deep into the tissue, completely noninvasively. There has long been interest in using this focal energy delivery to block nerve con...