Dexamethasone as an adjuvant for peripheral nerve blockade: a randomised, triple-blinded crossover study in volunteers.

BACKGROUND: The efficacy of dexamethasone in extending the duration of local anaesthetic block is uncertain. In a randomised controlled triple blind crossover study in volunteers, we tested the hypothesis that neither i.v. nor perineurally administered dexamethasone prolongs the sensory block achieved with ropivacaine. METHODS: Ultrasound-guided ulnar nerve blocks (ropivacaine 0.75% wt/vol, 3 ml, with saline 1 ml with or without dexamethasone 4 mg) were performed on three occasions in 24 male volunteers along with an i.v. injection of saline 1 ml with or without dexamethasone 4 mg. The combinations of saline and dexamethasone were as follows: control group, perineural and i.v. saline; perineural group, perineural dexamethasone and i.v. saline; i.v. group, perineural saline and i.v. dexamethasone. Sensory block was measured using a VAS in response to pinprick testing. The duration of sensory block was the primary outcome and time to onset of sensory block the secondary outcome. RESULTS: All 24 subjects completed the trial. The median [inter-quartile range (IQR)] duration of sensory block was 6.87 (5.85-7.62) h in the control group, 7.37 (5.78-7.93) h in the perineural group and 7.37 (6.10-7.97) h in the i.v. group (P=0.61). There was also no significant difference in block onset time between the three groups. CONCLUSION: Dexamethasone 4 mg has no clinically relevant effect on the duration of sensory block provided by ropivacaine applied to the ulnar nerve. CLINICAL TRIAL REGISTRATION: DRKS, 00014604; EudraCT, 2018-001221-98.

Ultrasound-Guided Approach for L5 Dorsal Ramus Block and Fluoroscopic Evaluation in Unpreselected Cadavers.

BACKGROUND AND OBJECTIVES: Medial branch blocks are frequently performed to diagnose lumbar facet-joint-mediated pain. Ultrasound guidance can increase practicability and eliminate exposure to ionizing radiation when compared with fluoroscopy. However, ultrasound-guided L5 dorsal ramus block, which, together with L4 medial branch block is necessary to anesthetize the most commonly affected facet joint L5/S1, has not been described so far. The objective of this study was to develop a technique and to evaluate its accuracy with standard fluoroscopy in unpreselected cadavers. METHODS: Twenty ultrasound-guided L5 dorsal ramus block approaches were performed with a new oblique out-of-plane technique in a rotated cross-axis view bilaterally in 10 cadavers. After checking the needle position in a second perpendicular sonographic plane, the final needle position was confirmed with conventional fluoroscopy by an independent observer. RESULTS: All cadavers had significant degenerations of the lumbar spine, and 5 of them had moderate to severe spondylolisthesis. Skin-to-target distances were 42 ±7 mm. Sixteen L5 dorsal ramus block attempts were located at the exact radiological target, 1 was slightly too lateral, and 3 were slightly too caudal (3-10 mm away). The overall success rate in unpreselected cadavers reached 80% (95% confidence interval, 56%-94%) and in the subgroup of corpses without spondylolisthesis 100% (95% confidence interval, 69%-100%). CONCLUSIONS: This is the first study to show that ultrasound-guided L5 dorsal ramus block is accurate and feasible in the absence of significant spondylolisthesis when performed with an oblique out-of-plane technique.

Ultrasonographic guidance improves the success rate of interscalene brachial plexus blockade.

BACKGROUND AND OBJECTIVES: The use of ultrasonography in regional anesthetic blocks has rapidly evolved over the past few years. It has been speculated that ultrasound guidance might increase success rates and reduce complications. The aim of our study is to compare the success rate and quality of interscalene brachial plexus blocks performed either with direct ultrasound visualization or with the aid of nerve stimulation to guide needle placement. METHODS: A total of 160 patients (American Society of Anesthesiologists physical status classification I-III) scheduled for trauma-related upper arm surgery were included in this randomized study and grouped according to the guidance method used to deliver 20 mL of ropivacaine 0.75% for interscalene brachial plexus blockade. In the ultrasound group (n = 80), the brachial plexus was visualized with a linear 5 to 10 MHz probe and the spread of the local anesthetic was assessed. In the nerve stimulation group (n = 80), the roots of the brachial plexus were located using a nerve stimulator (0.5 mA, 2 Hz, and 0.1 millisecond bandwidth). The postblock neurologic assessment was performed by a blinded investigator. RESULTS: Sensory and motor blockade parameters were recorded at different points of time. Surgical anesthesia was achieved in 99% of patients in the ultrasound vs 91% of patients in the nerve stimulation group (P < .01). Sensory, motor, and extent of blockade was significantly better in the ultrasound group when compared with the nerve stimulation group. CONCLUSIONS: The use of ultrasound to guide needle placement and monitor the spread of local anesthetic improves the success rate of interscalene brachial plexus block.

Ultrasound measurements of the distance between acupuncture needle tip at P6 and the median nerve.

BACKGROUND: Pericard 6 (P6) is one of the most frequently used acupuncture points, especially in preventing nausea and vomiting. At this point, the median nerve is located very superficially. OBJECTIVES: To investigate the distance between the needle tip and the median nerve during acupuncture at P6, we conducted a prospective observational ultrasound (US) imaging study. We tested the hypothesis that de qi (a sensation that is typical of acupuncture needling) is evoked when the needle comes into contact with the epineural tissue and thereby prevents nerve penetration. SETTINGS/LOCATION: The outpatient pain clinic of the Medical University of Vienna, Austria. SUBJECTS: Fifty (50) patients receiving acupuncture treatment including P6 bilaterally. INTERVENTIONS: Patients were examined at both forearms using US (a 10-MHz linear transducer) after insertion of the needle at P6. OUTCOME MEASURES: The distance between the needle tip and the median nerve, the number of nerve contacts and nerve penetrations, as well as the number of successfully elicited de qi sensations were recorded. RESULTS: Complete data could be obtained from 97 cases. The mean distance from the needle tip to the nerve was 1.8 mm (standard deviation 2.2; range 0-11.3). Nerve contacts were recorded in 52 cases, in 14 of which the nerve was penetrated by the needle. De qi was elicited in 85 cases. We found no association between the number of nerve contacts and de qi. The 1-week follow-up showed no complications or neurologic problems. CONCLUSIONS: This is the first investigation demonstrating the relationship between acupuncture needle placement and adjacent neural structures using US technology. The rate of median nerve penetrations by the acupuncture needle at P6 was surprisingly high, but these seemed to carry no risk of neurologic sequelae. De qi at P6 does not depend on median nerve contact, nor does it prevent median nerve penetration.

[Ultrasound in anesthesiology--ultrasound in interventional pain therapy]. / Ultraschall in der Anästhesiologie--Ultraschall kontrollierte interventionelle Schmerztherapie.

Ultrasound is an emerging new imaging and guiding technique for diagnostic or therapeutic interventional pain procedures. Advantages are the real time monitoring of the targeted structures, the placement of the instruments and the visualization of local anaesthetic spread without exposing patients and personal to radiation. Pain specialists need a large anatomical knowledge and training to use the new method safely and distinctively. The increasing published data available and the personal experience of the authors suggest a potential usefulness in interventional pain therapy, but also limitations.

Sonographic visualization and ultrasound-guided block of the third occipital nerve: prospective for a new method to diagnose C2-C3 zygapophysial joint pain.

BACKGROUND: Chronic neck pain after whiplash injury is caused by cervical zygapophysial joints in 50% of patients. Diagnostic blocks of nerves supplying the joints are performed using fluoroscopy. The authors' hypothesis was that the third occipital nerve can be visualized and blocked with use of an ultrasound-guided technique. METHODS: In 14 volunteers, the authors placed a needle ultrasound-guided to the third occipital nerve on both sides of the neck. They punctured caudal and perpendicular to the 14-MHz transducer. In 11 volunteers, 0.9 ml of either local anesthetic or normal saline was applied in a randomized, double-blind, crossover manner. Anesthesia was controlled in the corresponding skin area by pinprick and cold testing. The position of the needle was controlled by fluoroscopy. RESULTS: The third occipital nerve could be visualized in all subjects and showed a median diameter of 2.0 mm. Anesthesia was missing after local anesthetic in only one case. There was neither anesthesia nor hyposensitivity after any of the saline injections. The C2-C3 joint, in a transversal plane visualized as a convex density, was identified correctly by ultrasound in 27 of 28 cases, and 23 needles were placed correctly into the target zone. CONCLUSIONS: The third occipital nerve can be visualized and blocked with use of an ultrasound-guided technique. The needles were positioned accurately in 82% of cases as confirmed by fluoroscopy; the nerve was blocked in 90% of cases. Because ultrasound is the only available technique today to visualize this nerve, it seems to be a promising new method for block guidance instead of fluoroscopy.

Ultrasound-guided lumbar facet nerve block: accuracy of a new technique confirmed by computed tomography.

BACKGROUND: Lumbar facet nerve (medial branch) blocks are often used to diagnose facet joint-mediated pain. The authors recently described a new ultrasound-guided methodology. The current study determines its accuracy using computed tomography scan controls. METHODS: Fifty bilateral ultrasound-guided approaches to the lumbar facet nerves were performed in five embalmed cadavers. The target point was the groove at the cephalad margin of the transverse (or costal) process L1-L5 (medial branch T12-L4) adjacent to the superior articular process. Axial transverse computed tomography scans, with and without 1 ml contrast dye, followed to evaluate needle positions and spread of contrast medium. RESULTS: Forty-five of 50 needle tips were located at the exact target point. The remaining 5 were within 5 mm of the target. In 47 of 50 cases, the applied contrast dye reached the groove where the nerve is located, corresponding to a simulated block success rate of 94% (95% confidence interval, 84-98%). Seven of 50 cases showed paraforaminal spread, 5 of 50 showed epidural spread, and 2 of 50 showed intravascular spread. Despite the aberrant distribution, all of these approaches were successful, as indicated by contrast dye at the target point. Abnormal contrast spread was equally distributed among all lumbar levels. Contrast traces along the needle channels were frequently observed. CONCLUSIONS: : The computed tomography scans confirm that our ultrasound technique for lumbar facet nerve block is highly accurate for the target at all five lumbar transverse processes (medial branches T12-L4). Aberrant contrast medium spread is comparable to that of the classic fluoroscopy-guided method.

Lumbar plexus in children. A sonographic study and its relevance to pediatric regional anesthesia.

BACKGROUND: Pediatric regional anesthesia has gained increasing interest over the past decades. The current study was conducted to investigate the lumbar paravertebral region and the lumbar plexus at L3-L4 and L4-L5 by means of sonography to obtain fundamentals for the performance of ultrasound-guided posterior lumbar plexus blocks. METHODS: Thirty-two children (12 boys, 20 girls) with American Society of Anesthesiologists physical status I or II were enrolled in the current study. The lumbar paravertebral region was visualized at L3-L4 and L4-L5 on two corresponding posterior sonograms (longitudinal, transverse). The lumbar plexus had to be delineated, and skin-plexus distances were measured. In a series of five pediatric patients undergoing inguinal herniotomy, ultrasound-guided posterior lumbar plexus blocks at L4-L5 were performed. RESULTS: The children were stratified into three age groups (group 1: > 3 yr and 5 yr and 8 yr and

Ultrasound-guided lumbar facet nerve block: a sonoanatomic study of a new methodologic approach.

BACKGROUND: Lumbar facet nerve (medial branch) block for pain relief in facet syndrome is currently performed under fluoroscopic or computed tomography scan guidance. In this three-part study, the authors developed a new ultrasound-guided methodology, described the necessary landmarks and views, assessed ultrasound-derived distances, and tested the clinical feasibility. METHODS: (1) A paravertebral cross-axis view and long-axis view were defined under high-resolution ultrasound (15 MHz). Three needles were guided to the target point at L3-L5 in a fresh, nonembalmed cadaver under ultrasound (2-6 MHz) and were subsequently traced by means of dissection. (2) The lumbar regions of 20 volunteers (9 women, 11 men; median age, 36 yr [23-67 yr]; median body mass index, 23 kg/m2 [19-36 kg/m2]) were studied with ultrasound (3.5 MHz) to assess visibility of landmarks and relevant distances at L3-L5 in a total of 240 views. (3) Twenty-eight ultrasound-guided blocks were performed in five patients (two women, three men; median age, 51 yr [31-68 yr]) and controlled under fluoroscopy. RESULTS: In the cadaver, needle positions were correct as revealed by dissection at all three levels. In the volunteers, ultrasound landmarks were delineated as good in 19 and of sufficient quality in one (body mass index, 36 kg/m2). Skin-target distances increased from L3 to L5, reaching statistical significance (*, **P < 0.05) between these levels on both sides: L3r, 45+/-6 mm*; L4r, 48+/-7 mm; L5r, 50+/-6 mm*; L3l, 44+/-5 mm**; L4l, 47+/-6 mm; L5l, 50+/-6 mm**. In patients, 25 of 28 ultrasound-guided needles were placed accurately, with the remaining three closer than 5 mm to the radiologically defined target point. CONCLUSION: Ultrasound guidance seems to be a promising new technique with clinical relevance and the potential to increase practicability while avoiding radiation in lumbar facet nerve block.

Assessment of ventricular contractile function during orthotopic liver transplantation.

Hemodynamic alterations are a well-known phenomenon that influence the outcome of orthotopic liver transplantation (OLT). Whether or not myocardial dysfunction, which has various causes, contributes to this instability is still debated. Previous transesophageal echocardiography (TEE) studies have presented controversial data, not leading to final clarification. This is mainly because the impact of other contributing factors (inotropic support, alternating preload conditions and temperature) remained unaccounted for. We therefore measured the left ventricular shortening fraction (LVSF), a parameter reflecting myocardial contractility, in 10 consecutive patients undergoing OLT without veno-venous bypass. We measured during preparation (PP), during the anhepatic (AP) phase and the immediate reperfusion phase (RP). During the AP we observed a significant decrease of LVSF which never fell to subnormal levels in the majority of our patients, whereas during the RP, LVSF returned to PP values. These findings support the assumption that myocardial function is influenced by OLT, but that it plays only a minor role in the occurrence of hemodynamic instability, which could mainly be attributed to volume fluctuations.

Korean hand acupressure for motion sickness in prehospital trauma care: a prospective, randomized, double-blinded trial in a geriatric population.

UNLABELLED: Patients with trauma or medical illnesses transported to the hospital by ambulance have a frequent incidence of motion sickness. Because the administration of drugs in the ambulance is prohibited by law in Austria, the noninvasive Korean hand acupressure point at K-K9 may be an alternative against nausea and vomiting. We enrolled 100 geriatric patients with minor trauma, randomizing them into a K-K9 group and a sham acupressure group. We recorded visual analog scores (VAS) for nausea and for the patient's overall satisfaction with the treatment, hemodynamic variables, and peripheral vasoconstriction. In the K-K9 group, a significant (P < 0.01) increase in nausea was recorded in all cases: from VAS of 0 mm to 25 +/- 6 mm. A similarly significant (P < 0.01) increase was registered in the sham group: from VAS of 0 mm to 83 +/- 8 mm. However, at the time of arrival in the hospital, nausea scores were significantly different between the K-K9 group and the sham group (P < 0.01). Although all patients had been vasoconstricted at the emergency site before treatment, there was a significant difference (P < 0.01) between groups with regard to the number of vasoconstricted patients at the hospital (4 and 46 constricted and dilated, respectively, in the K-K9 group versus 48 and 2 constricted and dilated, respectively, in the sham group). On arrival in the hospital, a significant difference (P < 0.01) in heart rate was noted between the K-K9 group and the sham group (65 +/- 6 bpm versus 98 +/- 8 bpm). The patients' overall satisfaction with the provided care was significantly higher (P < 0.01) in the K-K9 group (19 +/- 9 mm VAS) than in the sham group (48 +/- 12 mm VAS). Neither group experienced a significant change in blood pressure. K-K9 stimulation was an effective and simple treatment for nausea during emergency care and significantly improved patient satisfaction. IMPLICATIONS: Korean hand acupressure at the K-K9 point was effective in reducing nausea and subjective symptoms of motion sickness in emergency trauma transport of patients at high risk of motion sickness.

Prone position in subarachnoid hemorrhage patients with acute respiratory distress syndrome: effects on cerebral tissue oxygenation and intracranial pressure.

OBJECTIVE: To analyze the effect of prone position on cerebral perfusion pressure and brain tissue oxygen partial pressure in subarachnoid hemorrhage patients with acute respiratory distress syndrome (ARDS). DESIGN: Clinical study with retrospective data analysis. SETTING: Neurosurgical intensive care unit of a primary level university hospital. PATIENTS: Sixteen patients treated for intracranial aneurysm rupture with initial Hunt and Hess grade III or worse who developed ARDS within 2 wks after the bleeding. INTERVENTIONS: Routine neurosurgical intensive care treatment for subarachnoid hemorrhage and posthemorrhagic vasospasm including cerebral monitoring with continuous intracranial pressure and brain tissue oxygen partial pressure recordings. MEASUREMENTS AND MAIN RESULTS: Hemodynamics, arterial oxygenation, ventilatory setting, intracranial pressure, cerebral perfusion pressure, and brain tissue oxygen partial pressure in the supine as well as in the prone position were analyzed and compared. A significant increase in Pao(2) from 97.3 +/- 20.7 torr (mean +/- sd) in the supine position to 126.6 +/- 31.7 torr in the prone position was joined by a significant increase in brain tissue oxygen partial pressure from 26.8 +/- 10.9 torr to 31.6 +/- 12.2 torr (both p <.0001), whereas intracranial pressure increased from 9.3 +/- 5.2 mm Hg to 14.8 +/- 6.7 mm Hg and cerebral perfusion pressure decreased from 73.0 +/- 10.5 mm Hg to 67.7 +/- 10.7 mm Hg (both p <.0001). CONCLUSIONS: The beneficial effect of prone positioning on cerebral tissue oxygenation by increasing arterial oxygenation appears to outweigh the expected adverse effect of prone positioning on cerebral tissue oxygenation by decreasing cerebral perfusion pressure in ARDS patients.

Prehospital analgesia with acupressure in victims of minor trauma: a prospective, randomized, double-blinded trial.

UNLABELLED: Untreated pain during the transportation of patients after minor trauma is a common problem in emergency medicine. Because paramedics usually are not allowed to perform invasive procedures or to give drugs for pain treatment, a noninvasive, nondrug-based method would be helpful. Acupressure is a traditional Chinese treatment for pain that is based on pain relief followed by a short mechanical stimulation of specific points. Consequently, we tested the hypothesis that effective pain therapy is possible by paramedics who are trained in acupressure. In a double-blinded trial we included 60 trauma patients. We randomly assigned them into three groups ("true points," "sham-points," and "no acupressure"). An independent observer, blinded to the treatment assignment, recorded vital variables and visual analog scales for pain and anxiety before and after treatment. At the end of transport, we asked for ratings of overall satisfaction. For statistical evaluation, one-way analysis of variance and the Scheffé F test were used. P < 0.05 was considered statistically significant. Morphometric and demographic data and potential confounding factors such as age, sex, pain, anxiety, blood pressure, and heart rate before treatment did not differ among the groups. At the end of transport we found significantly less pain, anxiety, and heart rate and a greater satisfaction in the "true points" groups (P < 0.01). Our results show that acupressure is an effective and simple-to-learn treatment of pain in emergency trauma care and leads to an improvement of the quality of care in emergency transport. We suggest that this technique is easy to learn and risk free and may improve paramedic-based rescue systems. IMPLICATIONS: We tested, in a double-blinded manner, the hypothesis that acupressure could be an effective pain therapy in minor-trauma patients. Our results show that acupressure is an effective and simple-to-learn treatment of pain in emergency medical care and can improve the quality of care.

Serum cholinesterase activity in patients with burns.

Serum cholinesterase activities were measured in 300 patients with thermal injuries. The samples were drawn immediately upon admission and thereafter daily until the time of the patients' discharge or death. According to the burn severity a characteristic decrease was noted during the first days. The decline during the first 24 hours as well as its value (measured 24 hours after admission) was found to be correlated with the total body surface area burned. In all patients the decrease in cholinesterase activity persisted for days, but in patients with inhalation trauma this decrease was significantly greater than in patients without lung injury. It seems that serum cholinesterase activity reflects not only the presence of an inhalation trauma. The cholinesterase measurement seems to be also a good method to observe the course of illness after a burn injury. Our data suggest a correlation between cholinesterase activity and morbidity. The inhalation trauma aggravates the thermal trauma.