Utilidad de los anestésicos locales en anestesia regional / Local anesthetics for regional anesthesia: an update

La anestesia regional en el siglo XXI, específicamente el bloqueos nervioso periférico y el bloqueo continuo de nervios periféricos, siguen gozando de una popularidad sin precedentes. A pesar de este resurgimiento de la popularidad, la investigación de un anestésico local nuevo y de acción más prolongada e inyectable con mejor perfil de seguridad sigue siendo un objetivo distante y difícil de lograr. Se han creado pocos anestésicos locales nuevos para uso clínico desde comienzos de la década de 1970. Los esfuerzos por mejorar la eficacia, la duración y la seguridad de los anestésicos locales inyectables incluyen aditivos y la nueva tecnología de localización de la aguja. Cualquier explicación convincente de los anestésicos locales de uso frecuente utilizados en la anestesia regional debe incluir un resumen detallado de la toxicidad de los anestésicos locales que incluya prevención, detección y tratamiento. Se plantea un enfoque específico sobre la aparición reciente de intralipid como tratamiento de la cardiotoxicidad inducida por anestésicos locales. Esta revisión de los anestésicos locales examinará la farmacología básica, explorará las tendencias actuales en la práctica de la anestesia regional y describirá los adelantos recientes en el uso clínico de los anestésicos locales y sus aditivos.

Regional anesthesia in the 21st century, specifically peripheral nerve blocks (PNBs) and continuous peripheralnerve blocks (CPNBs), continues to enjoy unparalleled popularity. Despite this resurgence in popularity, thesearch for a new, longer-acting local anesthetic (LA) forinjection with an improved safety profile remains anelusive and distant goal. A paucity of new local anestheticshas been developed for clinical use since the early 1970’s.Efforts to improve the efficacy, duration, and safety ofinjected LAs include drug additives to LAs and new need lelocalization technology. Any cogent discussion of the common LAs used with regional anesthesia must includea thorough summary of LA toxicity to include prevention,detection, and treatment. A specific focus on the recentemergence of Intralipid as a treatment for local anestheticinducedcardiac toxicity will ensue. This LA review willexamine basic pharmacology, explore current trends in regional anesthesia practice, and describe recent developments in the clinical use of LA and additives.

Clinical predictors of success and failure for lumbar facet radiofrequency denervation.

OBJECTIVE: To determine the clinical factors associated with the success and failure of radiofrequency denervation of the lumbar facet joints. METHODS: Clinical data were garnered from 3 academic medical centers on 192 patients with low back pain who underwent radiofrequency denervation after a positive response to diagnostic blocks. Success was defined as >/=50% pain relief lasting at least 6 months. Factors evaluated for their association with outcome included duration of pain, opioid use, symptom location, paraspinal tenderness, pain exacerbated by extension/rotation (ie, facet loading), MRI abnormalities, diabetes, smoking, scoliosis, obesity, prior surgery and levels treated. RESULTS: The only factor associated with a successful outcome was paraspinal tenderness. Variables that correlated with treatment failure were 'facet loading,' long duration of pain, and previous back surgery. CONCLUSIONS: It is counterproductive to use 'facet loading' as the sole basis for choosing patients for facet interventions. In patients at high risk for treatment failure, taking additional steps to reduce the rate of false-positive screening blocks may improve outcomes.

Responding to challenges in modern combat casualty care: innovative use of advanced regional anesthesia.

BACKGROUND: The war in Iraq has resulted in a high incidence of severe extremity injury requiring multiple surgical procedures and extensive rehabilitation. We describe the use of advanced regional anesthesia to meet this significant medical challenge. METHODS: From March 2003 to December 2004, 4,100 casualties have been evacuated to Walter Reed Army Medical Center (WRAMC). Of 1,400 inpatients, 750 have been battle-injured with 500 having extremity injuries. Of these, 287 (57%) received surgical care incorporating regional anesthesia including single-injection peripheral nerve blocks and continuous peripheral and epidural infusion catheters. Wounding, surgical, anesthetic, and outcomes data have been prospectively collected. RESULTS: Over 900 operations (mean 4+/-2/patient) were performed on 287 casualties prior to arrival at WRAMC, and 634 operations (mean 2+/-1/patient) were performed at WRAMC. Thirty-five percent of this cohort was amputees. In the study group, 646 advanced regional anesthesia procedures, including 361 continuous peripheral nerve blocks (CPNBs), were performed with a mean catheter infusion time of 9 days (1-34). Catheter-related complications occurred in 11.9% of casualties and were technical or minor in nature. Catheter-related infection rate was 1.9%. In 126 casualties with indwelling CPNB catheters, a significant decrease in pain score over 7 days was apparent (mean 3.7+/-0.2 to 2.2+/-0.2, P<0.001). CONCLUSION: Advanced regional anesthetic techniques allowed for safe perioperative surgical anesthesia and analgesia in the management of the modern combat casualty.

Continuous peripheral nerve block for battlefield anesthesia and evacuation.

Peripheral nerve and continuous peripheral nerve block (CPNB) have the potential to be valuable techniques in combat anesthesia. We describe the first successful application of CPNB in the pain management and surgical management of a combat casualty as he was evacuated from the Iraqi battlefield to the United States.