Inyección epidural interlaminar ecoguiada de esteroides: evaluación de rendimiento mediante el método de la suma acumulativa (CUSUM) / Ultrasound guided interlaminar epidural steroid injection: the cumulative sum method (CUSUM) for performance evaluation

Introducción: El uso de la ecografía para asistir o guiar la realización de procedimientos intervencionistas para tratamiento del dolor crónico se encuentra en crecimiento permanente. La inyección epidural de esteroides utilizando la ecografía en plano y en tiempo real es técnicamente más dificultosa, con curvas de aprendizaje más prolongadas aun en manos experimentadas. El lugar de la ecografía en este tipo de inyecciones aún no se encuentra establecido, debido en parte a la dificultad de detectar una inyección intravascular de la solución. Objetivo: El objetivo de este estudio fue la descripción de la inyección epidural de esteroides interlaminar ecoguiada, en plano y en tiempo real, en pacientes con dolor radicular lumbar. El aprendizaje de la técnica por el investigador principal fue evaluado estadísticamente utilizando el Método de la Suma Acumulativa (CUSUM). Pacientes y métodos: Un total de 25 pacientes con dolor radicular lumbosacro fueron seleccionados para recibir inyecciones epidurales interlaminares de esteroides en posición decúbito dorsal, utilizando la técnica ecoguiada en plano, en tiempo real, en eje corto o transversal. En todos los casos, un epidurograma de control fue realizado previo a la inyección de la solución de esteroides. El rendimiento de la técnica fue estudiado mediante la tasa de éxito de la misma, entendido como éxito a la obtención de un epidurograma sin necesidad de abandonar la técnica ecográfica en un tiempo menor a 10 minutos. El rendimiento del procedimiento fue estadísticamente evaluado por el método de la suma acumulativa (CUSUM), y la curva de aprendizaje aplicando este método fue construida. Resultados:La distancia promedio desde la piel al complejo posterior evaluada por el escaneo ecográfico previo al procedimiento fue de 6,7 ± 1,8 cm. De los 25 procedimientos realizados, en 21 se alcanzó el espacio epidural sin ayuda de la fluoroscopia, en un tiempo promedio de 4,8 ± 1,2 minutos.(AU)

Background: Real time ultrasound-guided epidural injections are considered technically more difficult than flouroscopy-guided procedures, with longer learning curves, even in experienced physicians. The cumulative sum (Cusum) method has been shown to be a useful tool to evaluate skill acquisition. The goal of our study was to assess the feasibility of real time, ultrasound guided, paramedian interlaminar epidural steroid injections, in patients with lumbosacral radicular pain. The evaluation of an experienced interventional pain physician´s learning curve of the technique is proposed, utilizing the CUSUM method. Patients and methods: The feasibility of the technique was studied by the success rate, which was considered the obtaining of an epidurogram exclusively using the ultrasound guide. For Cusum calculations, 20 % was taken as an acceptable failure rate and 40 % unacceptable failure rate. Results: Between August and December 2020, 25 patients were recruited, 15 females and 10 males. The average age of was 52 ± 12 years. In 21 procedures the epidural space was reached exclusively by ultrasound guide, in an average time of 5 ± 1.6 minutes. This implies a success rate of 84 %. In four procedures the epidural space was successfully achieved with the complementary use of fluroscopy. Using the Cumulative Sum method, the learning curve of the technique could be described on an experienced physician in ultrasound guided procedures. A 80 % success rate with statistical significance was obtained after performing 12 procedures. Conclusion: The "real time" ultrasound guided interlaminar epidural steroid injection in the transverse scan, is a feasibly and relatively easy to learn technique. The Cusum method could be a useful tool to assess skill acquisition in interventional pain medicine.(AU)

Accidental epidural catheter infusion of potassium chloride for postoperative analgesia: A case report.

An infusion of 100 cc of 0,2% potassium chloride was accidental performed through a thoracic epidural catheter, inserted to perioperative analgesia, to a 66 years old man who was scheduled for right hemicolectomy, 48 h after surgery. Paresis of upper limbs, flaccid paralysis of lower limbs and a sensitive level at T8 was observed. An epidural lavage with an initial dose of 20 cc of saline was slowly injected, followed for a saline infusion of 20 cc per hour. Neurologic signs were totally reverted some hours later and 24 h after the incident the physical exam was normal. We reviewed the clinical presentation of the complication and its mechanisms, the more frequent clinical evolution, as well as treatment measures and strategies to prevent the incident.

Radiofrecuencia pulsada del ganglio de la raíz dorsal para el dolor radicular lumbosacro: una revisión narrativa / Dorsal root ganlion pulsed radiofrequency for lumbosacral radicular pain: a narrative review

Objetivo: La radiofrecuencia pulsada constituye la variante no destructiva de la termolesión por radiofrecuencia. Una opción terapéutica en pacientes con síndrome radicular lumbosacro refractario a esteroides epidurales es la aplicación de RFP en el ganglio de la raíz dorsal. Si bien el mecanismo íntimo de acción de la misma no está del todo esclarecido, se plantea como una técnica de neuromodulación. La evidencia de la eficacia de esta intervención es débil por diversos factores: insuficientes estudios clínicos randomizados, el bajo tamaño muestral utilizado en los mismos, las controversias sobre algunos aspectos técnicos en la aplicación de la RFP, la selección incorrecta de pacientes, la presencia o no de dolor neuropático, etc. Nuestro objetivo es presentar una revisión de la evidencia de la eficacia y el perfil de seguridad de la RFP del GRD en pacientes con SRLS refractario. Los aspectos clínicos relacionados con la técnica y sus posibles mecanismos de acción son también reseñados. Material y métodos: Realizamos una búsqueda bibliográfica en MEDLINE (Pubmed), Google Scholar, Scopus, CINAHL, Embase, Cochrane y Fisterra (guías clínicas) en inglés y español para todos los años disponibles con los términos "Dorsal Root Ganglion pulsed radiofrequency" y "lumbar" o "lumbosacral radicular pain" en idioma inglés y español. La evaluación fue realizada por los dos autores de manera independiente. Resultados: Presentamos el análisis de ocho estudios prospectivos randomizados y nueve de cohorte única de tipo antes y después, de pacientes con dolor radicular lumbosacro refractario cuyos objetivos fueron la evaluación de la eficacia y seguridad de la técnica. Conclusiones: La RFP del GRD podría ser una opción terapéutica útil en el SRLS refractario, pudiendo considerarse sus resultados como preliminares, y deberán ser confirmados por estudios prospectivos randomizados con criterios de selección homogéneos y mayor número de pacientes.(AU)

Objective: Pulsed radiofrequency can be a non-destructive option compared with the thermical lesion produced by continuous radiofrequency. The application of PRF of the dorsal root ganglion is a therapeutic tool in patients with Lumbosacral Radicular Syndrome refractory to epidural steroids injections. The mechanisms of action are not clear yet and a neuromodulation process is proposed. The evidence of the efficacy of this intervention is of low quality, due to several factors. Our objective is to present a review of the evidence of the efficacy and safety profile of the DRG RFP. The clinical aspects related to the technique and its possible mechanisms of action are also reviewed. Material and methods: A bibliographic review was performed in MEDLINE (Pubmed), Google Scholar, Scopus, CINAHL, Embase, Cochrane and Fisterra (clinical guidelines) of articles in English and Spanish, during the available years with the terms: "Dorsal Root Ganglion pulsed radiofrequency" and "lumbar" or "lumbosacral radicular pain" in English and Spanish. Bibliographic review was carried out by the 2 authors independently. Results: We present the analysis of eight prospective, randomized studies and nine cohort studies, with a before and after type of design, in which the study of efficacy and safety was proposed as the main objective. Conclusions: This review suggested that PRF of the DRG can be a good therapeutic option in patients with refractory LRS. Larger, blinded, prospective and randomized controlled trials are needed to support this statement.(AU)

Accidental epidural catheter infusion of potassium chloride for postoperative analgesia: A case report. / Infusión accidental de cloruro de potasio a través de un catéter epidural para analgesia postoperatoria: reporte de caso clínico.

An infusion of 100cc of 0,2% potassium chloride was accidental performed through a thoracic epidural catheter, inserted to perioperative analgesia, to a 66years old man who was scheduled for right hemicolectomy, 48hours after surgery. Paresis of upper limbs, flaccid paralysis of lower limbs and a sensitive level at T8 was observed. An epidural lavage with an initial dose of 20cc of saline was slowly injected, followed for a saline infusion of 20cc per hour. Neurologic signs were totally reverted some hours later and 24hours after the incident the physical exam was normal. We reviewed the clinical presentation of the complication and its mechanisms, the more frequent clinical evolution, as well as treatment measures and strategies to prevent the incident.

Acute bladder inflammation differentially affects rat spinal visceral nociceptive neurons.

The present investigation examined the effect of inflammation produced by intravesical zymosan on spinal dorsal horn neuronal responses to urinary bladder distension (UBD). Extracellular single-unit recordings of neurons excited by UBD were obtained in spinalized female Sprague-Dawley rats. Neurons were classified as Type I-inhibited by heterotopic noxious conditioning stimuli (HNCS) or as Type II-not inhibited by a HNCS. In Experiment 1-following neuronal characterization, 1% zymosan was infused into the bladder and after 2h spinal units were recharacterized. Control rats received intravesical saline or subcutaneous zymosan. In Experiment 2-rats were pretreated with intravesical zymosan 24h prior to surgical preparation. Control rats received anesthesia only. 137 spinal dorsal horn neurons excited by UBD were characterized. In comparison with controls, Type II neurons demonstrated increased spontaneous and UBD-evoked activity following intravesical zymosan treatment (both Experiments 1 and 2) whereas Type I neurons demonstrated either no change (Experiment 1) or decreased activity (Experiment 2) following bladder inflammation. No significant changes were noted in neuronal activity in control experiments. Inflammation differentially affects subpopulations of spinal dorsal horn neurons excited by UBD that can be differentiated according to the effect of HNCS. This results in an altered pattern of spinal sensory transmission that may serve as the mechanism for the generation of visceral nociception.

[Orotracheal intubation training: assessment with the cumulative sum method]. / Evaluación del aprendizaje de la Intubación Orotraqueal mediante el método de la suma acumulativa (CuSum).

OBJECTIVES: Orotracheal intubation is one of the first techniques a new resident learns. The cumulative sum (cusum) method has been shown to be a useful tool for the assessment of learning, as it provides qualitative and quantitative information that allows technical competence to be certified. The aim of this study was to use the cusum method to assess the learning of orotracheal intubation by a group of first year residents. METHODS: The residents were evaluated at 2 stages. In the first, the acceptable failure rate was set at 10% and in the second it was reduced to 5%. Learning curves were constructed for each resident for both stages. RESULTS: Eight residents were evaluated. They performed 868 intubations, 330 at the first stage and 538 at the second. Forty (4.6%) of the intubations failed: 26 (7.9%) in the first stage and 14 (2.6%) in the second. All residents achieved the acceptable failure rate of 10% in the first 3 months with a mean (SD) number of intubations of 41.3 (6). All achieved the 5% acceptable failure rate within the 11 months of study, after a mean of 67.3 (28) intubations. CONCLUSIONS: The cusum method proved a useful tool for training residents to perform tracheal intubation. It afforded objective information on performance and facilitated evaluation while learning was taking place.

Evaluación del aprendizaje de la Intubación Orotraqueal mediante el método de la suma acumulativa (CuSum) / Orotracheal intubation training: assessment with the cumulative sum method

OBJETIVO: La intubación orotraqueal es una de lasprimeras técnicas que aprende el nuevo residente. Elmétodo de la suma acumulativa (“cumulative sum”,cusum) ha demostrado ser una herramienta útil en evaluarel aprendizaje, brindando información cualitativa,cuantitativa y permitiendo acreditar competencia en latécnica. El objetivo de este trabajo fue evaluar el aprendizajede la intubación orotraqueal mediante el métodode cusum en un grupo de residentes en su primer año.MÉTODOS: Evaluar a los residentes en dos etapas, unaprimera en la que se determinó un índice aceptable defallo de 10%, y una segunda, en la que se descendió a5%. Se construyeron las curvas de aprendizaje paracada residente en cada una de estas etapas.RESULTADOS: Se incluyeron 8 residentes. Se realizaron868 intubaciones, 330 fueron en la primera etapa y 538en la segunda. Se registraron 40 (4,6%) intubacionesfallidas, 26 (7,9%) en la primera etapa y 14 (2,6%) en lasegunda. Todos alcanzaron un índice aceptable de fallode 10%, en los 3 primeros meses con un promedio deintubaciones de 41,3 ± 6. Todos alcanzaron un índiceaceptable de fallo, de 5% en los 11 meses de estudio. Elpromedio de intubaciones para lograrlo fue de 67,3 ± 28.CONCLUSIONES: El método de cusum demostró ser unaimportante herramienta en la enseñanza de la intubacióntraqueal permitiendo brindar información objetivadel desempeño y permitiendo realizar una evaluaciónmientras se cumple la fase de aprendizaje

OBJECTIVES: Orotracheal intubation is one of the first techniques a new resident learns. The cumulative sum (cusum) method has been shown to be a useful tool for the assessment of learning, as it provides qualitative and quantitative information that allows technical competence to be certified. The aim of this study was to use the cusum method to assess the learning of orotracheal intubation by a group of first year residents. METHODS: The residents were evaluated at 2 stages. In the first, the acceptable failure rate was set at 10% and in the second it was reduced to 5%. Learning curves were constructed for each resident for both stages. RESULTS: Eight residents were evaluated. They performed 868 intubations, 330 at the first stage and 538 at the second. Forty (4.6%) of the intubations failed: 26 (7.9%) in the first stage and 14 (2.6%) in the second. All residents achieved the acceptable failure rate of 10% in the first 3 months with a mean (SD) number of intubations of 41.3 (6). All achieved the 5% acceptable failure rate within the 11 months of study, after a mean of 67.3 (28) intubations. CONCLUSIONS: The cusum method proved a useful tool for training residents to perform tracheal intubation. It afforded objective information on performance and facilitated evaluation while learning was taking place

Evidence for two populations of rat spinal dorsal horn neurons excited by urinary bladder distension.

Spinal L6-S2 dorsal horn neurons of cervical spinal cord-transected, decerebrate female rats were characterized using urinary bladder distension (UBD) as a visceral stimulus. Constant pressure, phasic, graded (20-80 mm Hg, 20 s) air UBD was delivered via a transurethral catether and extracellular single-unit recordings obtained from all neurons excited by UBD. Responses to graded UBD and noxious/non-noxious cutaneous stimuli were determined in 258 neurons which could be stratified into two groups based on their effect of a counterirritation stimulus: Type I neurons (n=112) were inhibited by noxious pinch presented in a non-segmental field; Type II neurons (n=146) were not similarly inhibited. Both Types of neurons were identified in both superficial and deep recording sites and demonstrated graded responses to graded UBD. All UBD-excited neurons had convergent cutaneous receptive fields (RFs) excited by non-noxious and/or noxious stimuli. As a group, Type I neurons had a period of decreased activity following termination of the distending stimulus whereas Type II neurons typically had a sustained afterdischarge. UBD-evoked activity in Type II neurons was inhibited more than similar activity in Type I neurons by both intravenous morphine and lidocaine. These results support the assertion that at least two different populations of spinal dorsal horn neurons exist which encode for a stimulus of urinary bladder distension. These populations are an analogue to previously characterized, similar neuronal populations excited by colorectal distension and suggest that they are representative of the overall phenomenon of visceral sensory processing, a component of which is nociception.

Vigor of visceromotor responses to urinary bladder distension in rats increases with repeated trials and stimulus intensity.

This methodological study characterized visceromotor responses (VMRs) as abdominal contractile responses to urinary bladder distension (UBD) in the female rat. Electromyographic activity of the abdominal musculature was used as a measure of the VMR. Similar to previously characterized cardiovascular responses to UBD, VMRs to UBD demonstrated an initial sensitization period whereby repeated presentation of UBD stimuli led to increase vigor of the VMR. Graded UBD produced graded VMRs, therefore stimulus-response functions could be constructed. The intravenous administration of the opioid fentanyl produced a reduced vigor of the VMR in a fashion consistent with its analgesic effect. The present report supports the utility of this model for studies of urinary bladder nociception.

Characterization of pressor and visceromotor reflex responses to bladder distention in rats: sources of variability and effect of analgesics.

PURPOSE: We assessed the usefulness of cardiovascular and visceromotor responses to bladder distention as measures of acute visceral nociception in rats by determining the reliability of these responses. MATERIALS AND METHODS: Halothane anesthetized male and female Sprague-Dawley rats were acutely instrumented with tracheal, jugular venous, carotid arterial and bladder cannulas. Wires were inserted into the abdominal musculature to enable myoelectrical activity measurement. Anesthesia was decreased until flexion reflexes were present. Repeat phasic and graded bladder distention was administered, and arterial blood pressure and abdominal electromyography activity were continuously monitored. We determined the effects of gender, vaginal smear estrous cycle stage and drug treatment on the measured responses. RESULTS: Bladder distention produced reliable pressor and visceromotor (abdominal contractile) responses. There was great inter-animal variability in response vigor but good reproducibility was noted within individual animals. During slow bladder filling bladder contractions were not noted at this level of anesthesia. Sex differences included a more vigorous reflex response in females than in males, which was most vigorous in females in proestrus. Repeat bladder distention led to increasingly vigorous pressor responses and the improved reliability of visceromotor responses. Intravenous morphine and lidocaine dose dependently inhibited the reflex responses. CONCLUSIONS: Pressor and visceromotor responses to bladder distention in halothane anesthetized rats are reliable measures of acute bladder nociception that may prove useful for analgesic screening and in studies of hormonal effects on nociception.