Neurological and histological outcomes after subarachnoid injection of a liposomal bupivacaine suspension in pigs: a pilot study.

BACKGROUND: An injectable liposomal bupivacaine suspension (EXPAREL™) is approved by the US Food and Drug Administration for analgesia by tissue infiltration and interscalene brachial plexus, but not for use in the neuraxial space. This pilot study describes neurological and histological outcomes of escalating doses of this extended-release formulation of bupivacaine after subarachnoid administration. METHODS: Twenty-five pigs (Sus scrofa domesticus) weighing 36.2 (4.4) kg were randomly assigned to one of five groups to receive a subarachnoid injection of sodium chloride 0.9%, 3 ml (negative control), preservative-free bupivacaine hydrochloride 0.5%, 3 ml (positive control), or one of three doses of liposomal bupivacaine suspension 1.33%: 1.5, 3, or 5 ml. After recovering from general anaesthesia, neurological outcomes were assessed by blinded observers. Three weeks later, the animals were sacrificed for histological evaluations of neurotoxicity. RESULTS: Animals that received sodium chloride 0.9%, bupivacaine hydrochloride, or liposomal bupivacaine 1.5 ml recovered within 2, 5, or 4 h, respectively. Animals that received liposomal bupivacaine 3 or 5 ml exhibited signs of neuraxial block (decreased nociception and proprioception) up to 32 h after injection. No histological evidence of neurotoxicity was found in any of the groups. CONCLUSIONS: Subarachnoid administration of liposomal bupivacaine in pigs exhibited a dose-response effect, and resulted in longer duration of neuraxial block than bupivacaine hydrochloride without histological evidence of neurotoxicity. Our study contributes preliminary data to inform further toxicological assessments and regulatory approval before subarachnoid administration in humans.

The effect of force applied to the left paratracheal oesophagus on air entry into the gastric antrum during positive-pressure ventilation using a facemask.

Cricoid force is widely applied to decrease the risk of pulmonary aspiration and gastric antral insufflation of air during positive-pressure ventilation, yet its efficacy remains controversial. We compared manual oesophageal compression at the low left paratracheal and cricoid levels for the prevention of gastric antral air insufflation during positive-pressure ventilation by facemask in patients scheduled for elective surgery under general anaesthesia. After gaining written consent, participants were randomly allocated by sealed envelope to one of three groups: oesophageal compression by 30 N paratracheal force (paratracheal group); oesophageal compression by 30 N cricoid force (cricoid group); or no oesophageal compression (control group). Gastric insufflation of air was assessed before and after positive-pressure ventilation by ultrasound measurement of the antral cross-sectional area and/or presence of air artefacts in the antrum. The primary outcome measure was the proportion of participants with ultrasound evidence of gastric insufflation. We recruited 30 patients into each group. Before facemask ventilation, no air artefacts were visible in the antrum in any of the participants. After facemask ventilation of the participant's lungs, no air artefacts were seen in the paratracheal group, compared with six subjects in the cricoid group and eight subjects in the control group (p = 0.012). Our results suggest that oesophageal compression can be achieved by the application of manual force at the low left paratracheal level and that this is more effective than cricoid force in preventing air entry into the gastric antrum during positive-pressure ventilation by facemask.

The effect of the volume of supra-inguinal injected solution on the spread of the injectate under the fascia iliaca: a preliminary study.

The fascia iliaca compartment is the compartment confined by the fascia iliaca (FI) and a muscular layer formed by the iliac- and psoas muscle. This compartment creates a virtual tunnel that contains the femoral nerve (FN), the obturator nerve (ON), and the lateral femoral cutaneous nerve (LFCN) of the lumbar plexus. In this pilot study, we aimed to determine the suggested volume needed to reach the three target nerves of the lumbar plexus (FN, ON, and LFCN) with a single-injection ultrasound-guided supra-inguinal fascia iliaca compartment (S-FICB). A computer tomography (CT scan)-guided step-up/step-down sequence was used to determine the suggested injection volume to target all three nerves. Subsequently, an anatomist blinded for the injected volume and CT findings, dissected the cadavers, and evaluated the spread of dye underneath the fascia iliaca. In total, seven pelvic areas of four cadavers were evaluated on CT scan and dissected. Distribution of dye underneath the FI in relation to the FN, ON, and the LFCN was recorded in all dissected cadavers. Combining CT and dissection findings, the suggested volume to reach the FN, ON, and LFCN with an S-FICB was 40 mL.

Neurotoxicity of perineural vs intraneural-extrafascicular injection of liposomal bupivacaine in the porcine model of sciatic nerve block.

Liposomal bupivacaine is a prolonged-release local anaesthetic, the neurotoxicity of which has not yet been determined. We used quantitative histomorphometric and immunohistochemical analyses to evaluate the neurotoxic effect of liposomal bupivacaine after perineural and intraneural (extrafascicular) injection of the sciatic nerve in pigs. In this double-blind prospective randomised trial, 4 ml liposomal bupivacaine 1.3% was injected either perineurally (n = 5) or intraneurally extrafascicularly (n = 5). Intraneural-extrafascicular injection of saline (n = 5) was used as a control. After emergence from anaesthesia, neurological examinations were conducted over two weeks. After harvesting the sciatic nerves, no changes in nerve fibre density or myelin width indicative of nerve injury were observed in any of the groups. Intraneural injections resulted in longer sensory blockade than perineural (p < 0.003) without persistent motor or sensory deficit. Sciatic nerve block with liposomal bupivacaine in pigs did not result in histological evidence of nerve injury.

Ultrasound guided injection inside the common sheath of the sciatic nerve at division level has a higher success rate than an injection outside the sheath / La inyección ecoguiada dentro de la fascia común del nervio ciático a nivel de la división es más eficaz que la inyección extrafascial

Background and objective: The recommendations for the level of injection and ideal placement of the needle tip required for successful ultrasound-guided sciatic popliteal block vary among authors. A hypothesis was made that, when the local anesthetic is injected at the division of the sciatic nerve within the common connective tissue sheath, the block has a higher success rate than an injection outside the sheath. Methods. Thirty-four patients scheduled for hallux valgus repair surgery were randomized to receive either a sub-sheath block (n = 16) or a peri-sheath block (n = 18) at the level of the division of the sciatic nerve at the popliteal fossa. For the sub-sheath block, the needle was advanced out of plane until the tip was positioned between the tibial and peroneal nerves, and local anesthetic was then injected without moving the needle. For the peri-sheath block, the needle was advanced out of plane both sides of the sciatic nerve, to surround the sheath. Mepivacaine 1.5% and levobupivacaine 0.5% 30 mL were used in both groups. The progression of motor and sensory block was assessed at 5 min intervals. Duration of block was recorded. Results: Adequate surgical block was achieved in all patients in the subsheath group (100%) compared to 12 patients (67%) in the peri-sheath group at 30 min. Sensory block was achieved faster in the subsheath than peri-sheath (9.1 ± 7.4 min vs. 19.0 ± 4.0; p < .001). Conclusions: Our study suggests that for successful sciatic popliteal block in less than 30 min, local anesthetic should be injected within the sheath (AU)

Fundamento y objetivo: Las recomendaciones sobre la posición ideal de la punta de la aguja para obtener un bloqueo poplíteo guiado por ultrasonidos efectivo varía según los autores. Nuestra hipótesis fue que la inyección del anestésico local dentro de la fascia común de tejido conectivo que recubre el nervio ciático a nivel de la división es más efectiva que la inyección por fuera de la misma. Métodos: Se incluyeron 34 pacientes programados para cirugía de hallux valgus con bloqueo poplíteo distribuidos aleatoriamente en 2 grupos: inyección subfascial (n=16) entre los nervios tibial y peroneo a nivel de la división sin modificar la posición de la aguja, e inyección perifascial (n=18) rodeando el nervio ciático al mismo nivel inyectando a ambos lados del mismo. Se administraron 30ml de una mezcla de mepivacaína al 1,5% y levobupivacaína la 0,5% en ambos casos. Se evaluó la instauración del bloqueo sensitivo cada 5 min y la duración del mismo. Resultados: A los 30 minutos todos los pacientes del grupo subfascial (100%) presentaron un bloqueo quirúrgico adecuado frente a 12 pacientes en el grupo perifascial (67%). La instauración del bloqueo sensitivo fue más rápida en el grupo subfascial que en el perifascial (9,1±7,4min frente a 19,0±4,0min; p<0,001). Conclusiones: Nuestro estudio evidencia que para asegurar un bloqueo poplíteo quirúrgico efectivo en menos de 30min el anestésico local debe inyectarse dentro de la fascia común

Ultrasound guided injection inside the common sheath of the sciatic nerve at division level has a higher success rate than an injection outside the sheath.

BACKGROUND AND OBJECTIVE: The recommendations for the level of injection and ideal placement of the needle tip required for successful ultrasound-guided sciatic popliteal block vary among authors. A hypothesis was made that, when the local anesthetic is injected at the division of the sciatic nerve within the common connective tissue sheath, the block has a higher success rate than an injection outside the sheath. METHODS: Thirty-four patients scheduled for hallux valgus repair surgery were randomized to receive either a sub-sheath block (n=16) or a peri-sheath block (n=18) at the level of the division of the sciatic nerve at the popliteal fossa. For the sub-sheath block, the needle was advanced out of plane until the tip was positioned between the tibial and peroneal nerves, and local anesthetic was then injected without moving the needle. For the peri-sheath block, the needle was advanced out of plane both sides of the sciatic nerve, to surround the sheath. Mepivacaine 1.5% and levobupivacaine 0.5% 30mL were used in both groups. The progression of motor and sensory block was assessed at 5min intervals. Duration of block was recorded. RESULTS: Adequate surgical block was achieved in all patients in the subsheath group (100%) compared to 12 patients (67%) in the peri-sheath group at 30min. Sensory block was achieved faster in the subsheath than peri-sheath (9.1±7.4min vs. 19.0±4.0; p<.001). CONCLUSIONS: Our study suggests that for successful sciatic popliteal block in less than 30min, local anesthetic should be injected within the sheath.

Incidence of intraneural needle insertion in ultrasound-guided femoral nerve block: A comparison between the out-of-plane versus the in-plane approaches / Incidencia de inserción intraneural en bloqueo femoral guiado por ecografía: comparación entre los enfoques en plano y fuera de plano

BACKGROUND: The optimal method of ultrasound-guided femoral nerve block (in-plane vs. out-of-plane) has not been established. We tested the hypothesis that the incidence of needle-nerve contact may be higher with out-of-plane than with in-plane needle insertion. METHODS: Forty-four patients with hip fracture (American Society of Anaesthesiologists physical status I-III) were randomized to receive the femoral block with an out-of-plane approach (needle inserted at a 45-60° angle 1 cm caudal to the midpoint of the ultrasound probe just above the femoral nerve) or with an in-plane technique (needle inserted 0.2-0.4 cm from the side of the probe lateral to the femoral nerve). Data collected included depth of needle insertion, response to nerve electric stimulation, and distribution of the injected volume in relation to the nerve (anterior vs. posterior, the latter assuming needle-nerve contact). The sensory block onset was tested at 20 min and block recovery and any neurologic symptoms were evaluated at 24 h. RESULTS: The incidence of needle-nerve contact was significantly higher with the out-of-plane approach (14/22 patients [64%]) than with the in-plane approach (2/22 patients [9%]) (p < 0.001) (OR = 17.5, 95% CI: 4-79). The rate of paraesthesia on crossing the fascia iliaca was similar in the two groups. All blocks uneventfully regressed; and no patient developed neurologic symptoms. CONCLUSIONS: Under the conditions of our study, needle-nerve contact during femoral nerve block occurs frequently with the out-of-plane approach. An in-plane approach results in an equally effective femoral block and less incidence of needle-nerve contact

ANTECEDENTES. No ha quedado establecido un método adecuado para el bloqueo femoral guiado por ecografía (en plano frente a fuera de plano). Probamos la hipótesis de que la incidencia del contacto entre la aguja y un nervio puede ser mayor en la inserción fuera de plano que en el abordaje en plano. MÉTODOS: Cuarenta y cuatro pacientes con fractura de cadera (estadio i-iii según la Sociedad Americana de Anestesiólogos) recibieron de manera aleatorizada un bloqueo femoral con un enfoque fuera de plano (inserción de la aguja en ángulo de 45-60° y 1 cm caudal a la sonda de ecografía sobre el nervio femoral) o con una técnica en plano (inserción de la aguja 0,2-0,4 cm desde el lado de la sonda lateral al nervio femoral). Entre los datos recopilados se incluían la profundidad de inserción de la aguja, la reacción a la estimulación nerviosa y la distribución del volumen inyectado en función del nervio (anterior comparado con posterior, este último con contacto entre la aguja y un nervio). Se analizó el inicio del bloqueo a los 20 min y se evaluaron la recuperación del bloqueo y los síntomas neurológicos después de 24 h. RESULTADOS: La incidencia del contacto entre la aguja y los nervios fue significativamente mayor con el enfoque fuera de plano (14/22 pacientes [64%]) que con el abordaje en plano (2/22 pacientes [9%]) (p < 0,001) (OR = 17,5 [95%]; IC: 4-79). El grado de parestesia en aponeurosis fue similar en ambos grupos. Se revirtieron todos los bloqueos sin incidentes; ningún paciente desarrolló síntomas neurológicos. CONCLUSIONES: En las condiciones de nuestro estudio, el contacto entre la aguja y un nervio durante el bloqueo femoral sucede a menudo con el enfoque fuera de plano. Un abordaje en plano tiene como resultado un bloqueo femoral igualmente efectivo, y una incidencia menor del contacto entre la aguja y un nervio

Incidence of intraneural needle insertion in ultrasound-guided femoral nerve block: a comparison between the out-of-plane versus the in-plane approaches.

BACKGROUND: The optimal method of ultrasound-guided femoral nerve block (in-plane vs. out-of-plane) has not been established. We tested the hypothesis that the incidence of needle-nerve contact may be higher with out-of-plane than with in-plane needle insertion. METHODS: Forty-four patients with hip fracture (American Society of Anaesthesiologists physical status I-III) were randomized to receive the femoral block with an out-of-plane approach (needle inserted at a 45-60° angle 1cm caudal to the midpoint of the ultrasound probe just above the femoral nerve) or with an in-plane technique (needle inserted 0.2-0.4 cm from the side of the probe lateral to the femoral nerve). Data collected included depth of needle insertion, response to nerve electric stimulation, and distribution of the injected volume in relation to the nerve (anterior vs. posterior, the latter assuming needle-nerve contact). The sensory block onset was tested at 20 min and block recovery and any neurologic symptoms were evaluated at 24h. RESULTS: The incidence of needle-nerve contact was significantly higher with the out-of-plane approach (14/22 patients [64%]) than with the in-plane approach (2/22 patients [9%]) (p<0.001) (OR=17.5, 95% CI: 4-79). The rate of paraesthesia on crossing the fascia iliaca was similar in the two groups. All blocks uneventfully regressed; and no patient developed neurologic symptoms. CONCLUSIONS: Under the conditions of our study, needle-nerve contact during femoral nerve block occurs frequently with the out-of-plane approach. An in-plane approach results in an equally effective femoral block and less incidence of needle-nerve contact.

Use of ultrasound-guided intercostal nerve block as a sole anaesthetic technique in a high-risk patient with Duchenne muscular dystrophy.

Duchenne muscular dystrophy is a progressive neuromuscular disease. Mortality is typically related to combined respiratory failure and dilated cardiomyopathy. Surgery under general anesthesia or deep sedation presents increased risks for pulmonary complications or ventilator dependency postoperatively. We describe the utility of ultrasound guided intercostal nerve blocks for surgery on the chest wall in a patient with Duchenne muscular dystrophy and severe respiratory compromise.

Intraneural injection during nerve stimulator-guided sciatic nerve block at the popliteal fossa.

BACKGROUND: Exact location of the needle tip during nerve stimulation-guided peripheral nerve blocks is unknown. Using high-frequency ultrasound imaging, we tested the hypothesis that intraneural injection is common with nerve stimulator-guided sciatic nerve (SN) block in popliteal fossa. METHODS: Forty-two patients scheduled for hallux valgus repair were studied. Sciatic block at the popliteal fossa was accomplished using nerve stimulation. When a motor response was elicited at <0.5 mA (2 Hz, 0.1 ms), 40 ml of local anaesthetic (LA) was injected. Using ultrasound (Titan, Sonosite, 5-10 MHz), the diameters and area of the SN were measured before and after the injection. The presence of nerve swelling and proximal or distal diffusion of LA were also assessed. Intraneural injection was defined as nerve area (NA) increase of > OR =15% and one or more additional ultrasonographic markers (nerve swelling, proximal-distal diffusion within epineural tissue). Clinical neurological evaluation was performed 1 week after the block. RESULTS: Post-injection NA increase > OR =15% was seen in 32 (76%) patients [0.54 (SD 0.19) cm(-2) vs 0.76 (0.24) cm(-2); P<0.05]. Nerve swelling with fascicular separation was observed in 37 (88%) patients; proximal and distal diffusion of LA were present in six (14%) and 14 (38%) patients, respectively. Intraneural injection criteria were met in 28 (66%) patients. Greater NA increase was present in patients with fast block onset [61 (45) vs 25 (33)%; (Dif 35% 95% CI 61-9%); P<0.05]. No patient developed neurological complications. CONCLUSIONS: Intraneural (subepineural) injection is a common occurrence after nerve stimulator-guided SN block at the popliteal fossa, yet it may not inevitably lead to neurological complications.

[Lyme borreliosis in Bosnia and Herzegovina--clinical, laboratory and epidemiological research]. / Lajmska borelioza u Bosni i Hercegovini--klinicka, laboratorijska i epidemioloska istrazivanja.

UNLABELLED: Lyme borreliosis is multisistemic zoonosis that is transmitted from animals to humans by ticks of the Ixodes ricinus complex, which presents vectors for causative organism. Lyme borreliosis is caused by Borelia burgdorferi sensu lato, which has four different species. Objective of this research was to investigate frequency of borreliosis on our material, to determine seasonal yearly distribution of disease and to investigate variability of clinical forms of disease. MATERIALS AND METHODS: Retrospective analysis of medical records and discharge notes of treated patients with borreliosis in period 01 January 1996-31 December 2006 was conducted at the Clinic for Infectious Diseases in Sarajevo. Diagnosis of disease was confirmed serologically using Indirect Immunofluorescency method (IF), ELISA and Western-blot methods. RESULTS: During the investigated period at Clinic for Infectious Diseases, 51 patient with borreliosis was treated. Most affected was work-capable population. Since year 2000 number of treated patients is increasing. Disease is registered from May to September with peak in June. Most frequent symptoms were fever, fatigue, myalgias, and arthralgias. Disease was mainly diagnosed as Erythema migrans (39), than neuroborreliosis (7), borelial arthritis (4) and rarely eye infections-endophtalmitis and episcleritis. CONCLUSION: based on conducted 11-year period research of borreliosis we can conclude following: disease is mainly diagnosed as Erythema migrans, followed by neuroborreliosis. Women were more affected than men. Work-capable population is exposed to higher risk of getting disease. Highest peak of disease was in June. Due to various clinical forms and severity of late complications (II and III stage) it would be useful to conduct borreliosis testing with every etiologically unexplained neurological, cardiac and bone-joint manifestation.

Neurologic and histologic outcome after intraneural injections of lidocaine in canine sciatic nerves.

BACKGROUND: Inadvertent intraneural injection of local anesthetics may result in neurologic injury. We hypothesized that an intraneural injection may be associated with higher injection pressures and an increase in the risk of neurologic injury. METHODS: The study was conducted in accordance with the principles of laboratory animal care, and was approved by the Laboratory Animal Care and Use Committee. Fifteen dogs of mixed breed (16-21 kg) were studied. After general endotracheal anesthesia, the sciatic nerves (n= 30) were exposed bilaterally. Under direct vision, a 25-gauge, long-beveled needle (30 degrees) was placed either epineurally (n= 10) or intraneurally (n= 20), and 4 ml of preservative-free lidocaine 20 mg/ml was injected using an automated infusion pump (4 ml/min). Injection pressure data were acquired using an in-line manometer coupled to a computer via an analog-to-digital conversion board. After injection, the animals were awakened and subjected to serial neurologic examinations. One week later, the dogs were killed, the sciatic nerves excised and histologic examination was performed by pathologists blind to the purpose of the study. RESULTS: All perineural injections resulted in low pressures (< or = 5 psi). In contrast, eight of 20 intraneural injections resulted in high pressures (20-38 psi) at the beginning of the injection. Twelve intraneural injections, however, resulted in pressures of less than 12 psi. Neurologic function returned to baseline within 3 h after perineural injections and within 24 h after intraneural injections, when the measured injection pressures were less than 12 psi. Neurologic deficits persisted throughout the study period after all eight intraneural injections that resulted in high injection pressures. Histologic examination of the affected nerves revealed fascicular axonolysis and cellular infiltration. CONCLUSIONS: The data in our canine model of intraneural injection suggest that intraneural injections do not always lead to nerve injury. High injection pressures during intraneural injection may be indicative of intrafascicular injection and may predict the development of neurologic injury.