Vascular Puncture Research Articles

Effects of local anaesthetic dilution on the characteristics of ultrasound guided axillary brachial plexus block: a randomised controlled study

Ultrasound guidance has led to marked improvement in the success rate and characteristics of peripheral nerveblocks. However, effects of varying the volume or concentration of a fixed local anaesthetic dose on nerve block remains unclear.The purpose of our study was to evaluate whether at a fixed dose of lidocaine, altering the volume and concentration willhave any effect on the onset time of ultrasound-guided axillary brachial plexus block. Twenty patientswere randomised to receive an ultrasound-guided axillary brachial plexus block with either lidocaine 2% with epinephrine (20ml, Group 2%) or lidocaine 1% with epinephrine (40 ml, Group 1%). The primary endpoint was block onset time. Secondaryoutcomes included duration of the block, performance time, number of needle passes, incidence of paraesthesia and vascularpuncture. The median [IQR] onset time of surgical anaesthesia was shorter in Group 1% when compared to Group2% (6.25 [5-7.5] min vs 8.75 [7.5-10] min; p=0.03). The mean (SD) overall duration of surgical anaesthesia was significantlyshorter in Group 1% compared to Group 2% (150.9±17.2 min vs 165.1±5.9 min; p=0.02). Group 1% had a shorter performancetime with fewer needle passes. The incidence of vascular puncture and paraesthesia was similar in the two groups. Ultrasound-guided axillary brachial plexus blocks performed using a higher volume of lower concentration lidocainewas associated with shorter onset time and duration of surgical anaesthesia.

Axilary Block Ultrasound Guiding in Patient with Pseudoaneurysm Regio Brachii Sinistra pro Repair Pseudoaneurysm

Background: An aneurysm may be a true aneurysm or a pseudoaneurysm. Pseudoaneurysm is defined as a defect in the arterial wall, making a connection between the lumen and the extraluminal space. The main etiology of brachial artery pseudoaneurysm is incidental arterial puncture during venous cannulation for hemodialysis. Case:: Anesthetic management was performed on a female patient 56 years old, body weight 45 kg, height 150 cm. The patient had other comorbidities such as hypertension, diabetes mellitus, chronic renal kidney with a diagnosis of left brachial pseudoanuerysm. Pro Pseudoanurysm repair surgery. The anesthetic technique uses axillary peripheral nerve block with ultrasound guiding. The duration of surgery is ± 120 minutes. After the operation, the patient was treated in the hospital ward. Conclusion: Choosing the most appropriate anesthetic technique for patients with renal impairment is necessary to maintain normovolemia and normotension in order to avoid unexpected complications. Using regional anesthetic technique for sympathetic nerve block may be favorable in these patients. With ultrasound guiding, the incidence of failure is lower, the time required is shorter, the latency is shorter, the blockade is longer, and the risk of accidental vascular puncture is lower so that vascular lesions are less likely.

Pain relief after maxillofacial surgery: efficacy in patients undergoing ultrasound- guided trigeminal nerve block – a randomized controlled trial

Background: Pain management is a critical factor for successful surgical outcomes, as it enables patients to recover more quickly. Maxillofacial surgery is typically complex and requires appropriate pain relief methods. In this study, the use of ultrasound to guide the blocking of the trigeminal nerve was investigated. Methods: The study enrolled 60 patients in a randomized controlled trial. The patients were divided into two groups: group T received a trigeminal (V) nerve block using ropivacaine under ultrasound guidance; and group C, the control group, received paracetamol infusion. During follow up, the following outcomes were assessed: time required for the first dose of pain relief; 24-hour dose of ketorolac in both groups; visual analog scale (VAS) score at rest and when moving; changes in hemodynamics, including pulse, systolic blood pressure, diastolic and blood pressure and changes in respiration including respiratory rate, and SpO2. Systemic complications such as allergies, anaphylaxis, drug overdose, and anesthetic toxicity, as well as local complications such as vascular puncture, nerve damage, hematoma at the injection site, facial paralysis, jaw dropping, and paresthesia/numbness of the lips and tongue were evaluated. Results & Conclusion: The results showed that blocking branches V2 and V3 of the trigeminal nerve under ultrasound guidance improved pain relief in patients compared to the intravenous paracetamol. The VAS score of the study group was lower than that of the control group in most cases. In addition, the investigated group could tolerate pain longer until the later first dose of analgesic with a lower dose of ketorolac, which suggests the potential of this intervention in managing pain from maxillofacial surgery.

Smart Bio-Impedance-Based Sensor for Guiding Standard Needle Insertion.

A venipuncture is the most common non-invasive medical procedure, and is frequently used with patients; however, a high probability of post-injection complications accompanies intravenous injection. The most common complication is a hematoma, which is associated with puncture of the uppermost and lowermost walls. To simplify and reduce complications of the venipuncture procedure, and as well as automation of this process, a device that can provide information of the needle tip position into patient’s tissues needs to be developed. This paper presents a peripheral vascular puncture control system based on electrical impedance measurements. A special electrode system was designed to achieve the maximum sensitivity for puncture identification using a traditional needle, which is usually used in clinical practice. An experimental study on subjects showed that the electrical impedance signal changed significantly once the standard needle entered the blood vessel. On basis of theoretical and experimental studies, a decision rule of puncture identification based on the analysis of amplitude-time parameters of experimental signals was proposed. The proposed method was tested on 15 test and 9 control samples, with the results showing that 97% accuracy was obtained.

Supraclavicular Brachial Plexus Block by Nerve Stimulator or Ultrasound: An Observational Cross-sectional Study

Introduction: Supraclavicular approach to the brachial plexus block is considered to be one of the most effective anaesthetic procedures for upper limb surgeries. Peripheral Nerve Stimulation (PNS) has traditionally been used as the gold standard technique for nerve location. More recently, Ultrasound (USG)-guided single injection supraclavicular block is used which allows direct visualisation of nerve, but its use is limited by cost constraints and the level of expertise needed. Aim: To compare the efficacy of USG and PNS in supraclavicular brachial plexus block especially the onset of motor block in orthopaedic forearm surgeries. Materials and Methods: An observational cross-sectional analytical study was conducted from January 2019 to January 2020 on 60 patients attending emergency operation theatre for orthopaedic forearm surgeries. They were allocated alternatively to one of the two groups (30 in each group) based on the technique of nerve block, either using USG or PNS. Block execution time (puncture time), the number of needle passes, time of onset of sensory block, time of onset of motor block, quality of sensory block, quality of motor block, the intraoperative requirement of opioids, complications, success, and failure were the exposure variables. The qualitative data were compared using Chi-square test and for comparison of the continuous variable, the student’s t-test and Fisher’s exact test were used. The p-value<0.05 was considered statistically significant. Results: Patients in both groups were comparable concerning demographic parameters like age, sex, and American Society of Anaesthesiologists (ASA) physical status. The mean time of onset of a motor block using the USG-guided technique was 8.6±1.0 minutes, and using a PNS was 11.1±1.0 minutes (p-value<0.01). There was a 93.3% success rate in the USG- guided technique, compared to an 83.3% success rate in the PNS method (p-value of 0.222). No complications were seen in the USG-guided group. In the PNS-guided group, four complications were noted among 30 patients, the most common being vascular puncture (2 cases). Conclusion: USG-guided supraclavicular block was superior to PNS technique in terms of rapid onset motor and sensory block, block quality, improved success rate, and fewer complications.

AI-Enabled, Ultrasound-Guided Handheld Robotic Device for Femoral Vascular Access.

Hemorrhage is a leading cause of trauma death, particularly in prehospital environments when evacuation is delayed. Obtaining central vascular access to a deep artery or vein is important for administration of emergency drugs and analgesics, and rapid replacement of blood volume, as well as invasive sensing and emerging life-saving interventions. However, central access is normally performed by highly experienced critical care physicians in a hospital setting. We developed a handheld AI-enabled interventional device, AI-GUIDE (Artificial Intelligence Guided Ultrasound Interventional Device), capable of directing users with no ultrasound or interventional expertise to catheterize a deep blood vessel, with an initial focus on the femoral vein. AI-GUIDE integrates with widely available commercial portable ultrasound systems and guides a user in ultrasound probe localization, venous puncture-point localization, and needle insertion. The system performs vascular puncture robotically and incorporates a preloaded guidewire to facilitate the Seldinger technique of catheter insertion. Results from tissue-mimicking phantom and porcine studies under normotensive and hypotensive conditions provide evidence of the technique’s robustness, with key performance metrics in a live porcine model including: a mean time to acquire femoral vein insertion point of 53 ± 36 s (5 users with varying experience, in 20 trials), a total time to insert catheter of 80 ± 30 s (1 user, in 6 trials), and a mean number of 1.1 (normotensive, 39 trials) and 1.3 (hypotensive, 55 trials) needle insertion attempts (1 user). These performance metrics in a porcine model are consistent with those for experienced medical providers performing central vascular access on humans in a hospital.

Use of Peripheral Venous Blood Gas Analysis and Oximetry to Assess Respiratory Failure in the Emergency Department

Purpose: The diagnosis of acute respiratory failure (ARF) is based on arterial blood gas analysis (ABGA), which is associated with patient discomfort and requires an additional vascular puncture. Our aim was to compare ABGA with peripheral venous blood gas analysis (PVBGA) and pulse oximetry in adult patients with dyspnea and/or suspected ARF.Methods: We included 102 patients (56 males) in a prospective study performed in a medical emergency department from March–May 2019. Patients with overt signs of circulatory shock or severe respiratory failure were not included.Results: We showed significant positive correlations between ABGA and PVBGA results (for pH, ρ=0.590; for HCO3, ρ=0.901; and for pCO2, ρ=0.740), and insignificant differences between oxygen saturation based on ABGA and pulse oximetry (95% vs. 94%; p=0.49). When we subtracted 1 kPa from the venous pCO2 and added 4 kPa to the venous pO2 , there were no statistically significant differences between peripheral venous and arterial pCO2 and pO2 (4.8 vs. 4.7 kPa, p=0.26 and 9.5 vs. 8.9 kPa, p=0.21, respectively).Conclusion: The combination of PVBGA and pulse oximetry provided sufficient data to make clinical decisions in a select group of patients with dyspnea and/or ARF.

Comparative evaluation of landmark technique and ultrasound-guided caudal epidural injection in pediatric population: A systematic review and meta-analysis.

Caudal block is a common regional anesthesia technique in pediatrics with landmark method predominantly being practiced. Ultrasound-guided technique provides real-time visualization of the structures and injection while performing caudal block. We performed this meta-analysis to determine the utility of ultrasound in caudal blocks in children over the landmark-based technique. Randomized controlled trials comparing ultrasound-guided caudal blocks and landmark technique in pediatrics were searched from databases-PubMed, Embase, Scopus, and CENTRAL from inception until August 2020. The primary objective was success rate between the two techniques and secondary objectives included time to perform the block, first puncture success, and complications. Five trials with 904 participants were included for this meta-analysis. There was no difference in success rate between the two techniques (Risk ratio-1.07; 95% CI [0.97, 1.18]; p=.15). Time to perform the block was similar (Mean difference-8.88s; 95% CI [-21.64, 39.40; p=.57) while first puncture success was higher with ultrasound-guided technique (Risk ratio-1.31; 95% CI [1.15, 1.49]; p=.0001). Complications like vascular puncture and needle misplacement were lower in the ultrasound group, and no serious complications were seen in any patient. Needle visualization and sacral canal distension were seen in 82% and 97.5% of the cases, respectively, in ultrasound group. Ultrasound-guided caudal injection does not improve the success rate or time to perform the block but results in higher first puncture success and lower incidence of complications compared to landmark technique.

The comparison of analgesic efficacy between ultrasound-guided continuous thoracic paravertebral block and continuous thoracic epidural block using bupivacaine - fentanyl in patients undergoing lung surgery: A prospective, randomized, controlled trial.

This study aimed to compare the efficacy and the safety of ultrasound-guided continuous thoracic paravertebral block (CTPB) to the continuous thoracic epidural block (CTEB) for pain relief in patients undergoing lung surgery. Our study included 102 patients after lung surgery at the 74 Central Hospital from 9/2013 to 12/2017. Patients were divided into 2 groups: CTPB group (n= 51) and CTEB group (n= 51). The primary outcomes were the Visual Analogue Scale (VAS) scores when patients were at rest (VR) and movement (VM), the total used dosage of bupivacaine - fentanyl after surgery, plasma glucose, and cortisol levels, additional doses of morphine. Adverse reactions were recorded during the study. The study was approved by the Ethics Committee of the 74 Central Hospital. All participants provided their informed consent. There were no significant differences between CTPB and CTEB groups in terms of the VR and the VM, total used doses of bupivacaine - fentanyl after 72-hours of surgery (p> 0.05), the increased plasma glucose, and plasma cortisol (p> 0.05), and the additional doses of morphine. The percent of patients in the CTPB group undergoing adverse reactions in the circular system and the respiratory system was lower than in the CTEB group. Adverse reactions included vascular puncture, urinary retention, and itch. Ultrasound-guided CTPB is an effective intervention of pain relief after lung surgery. Its analgesic efficacy is comparable to CTEB. Also, this method had fewer adverse reactions in circulation and respiration compared to the CTEB.

Comparison between Single- and Double-Injection Technique for Ultrasound-Guided Supraclavicular Block: A Randomized Controlled Study

Background: The supraclavicular approach to brachial plexus block is a commonly employed regional anesthesia technique for providing surgical anesthesia and postoperative analgesia for patients undergoing upper limb fractures. With ultrasound (US) guidance, the success rate of the block is increased, and complications like pneumothorax and vascular puncture are minimized. The block can be performed using single injection at the corner pocket or double injection, that is, half of the drug at the corner pocket and the remaining half at the cluster of brachial plexus divisions. Methods: After institutional ethics committee approval, we randomized 40 patients scheduled with fractures for elective upper extremity surgery under US-guided supraclavicular brachial plexus block. Twenty patients received 30 mL of local anesthetic at the corner pocket (group SI), and 20 patients received 30 mL of local anesthetic using the dual-injection technique in divided doses (group DI). Demographic data, time to block performance, time to sensory and motor block, total anesthesia-related time (TART), block success, and failure were compared between both groups. Results: The demographic data were comparable between both groups. The DI group had a significantly faster onset than the SI group (p = 0.0172). There was a statistically significant lesser performance time in group SI than in group DI (p < 0.034). The sensory and motor block achieved was comparable between both groups. Conclusion: The success rates in both the SI and DI techniques are comparable. The DI technique results in a faster onset and hence a shorter TART; however, it may not be clinically relevant.

Prospects for improving primary health care to children with thermal injuries

Introduction. Burn injury in children has been and remains one of the most significant cause of disability and death in the world. An important aspect in relation to the prognosis and course of the wound process is the quality of the first aid provided at the prehospital stage. Untimely diagnosed shock, inadequately prescribed anesthesia, attempts to perform surgical treatment of wounds at the site of the accident can fatally affect the prognosis of the disease.Material and methods. A retrospective analysis of medical documentation of 328 children who were treated at the burn center from 2016 to 2019 was made. Selection criteria were: arrival to the center by ambulance, shock, transfer to ICU. To analyze actions performed in the prehospital stage, a number of parameters were identified: diagnosis, length of transportation, specialists in the ambulance team, TBSA (total burn surface area), thermal inhalation lesion, and others.Results. The overwhelming majority of errors refer to diagnostics: shock (94.5%), incorrect TBSA assessment (63.7%), inadequate pain relief (61.9%), etc. A reliable correlation was revealed between ineffective analgesia and incorrect assessment of thermal lesion area. Life-threatening conditions develop in case of incorrect primary surgical treatment of wounds, incorrect vascular puncture, tracheal intubation, etc.Conclusions. The revealed difficulties in providing the primary medical aid to burnt patients at the site of accident require the development of a clearer and more understandable algorithm for medical personnel who provide the first aid to children with burns.

Creating Low-Cost Phantoms for Needle Manipulation Training in Interventional Radiology Procedures

Image-guided procedures play a critical role in the clinical practice of radiologists. Training radiology residents in these procedures, with early teaching of basic but fundamental skills, is therefore crucial to develop competence before they become autonomous and start their practice. It has been proposed in the literature that low-fidelity phantoms are appropriate to teach novice trainees. The authors propose a series of phantoms to teach the core skills necessary to perform procedures early in resident training. The phantoms described can be used to train skills necessary for performing US-guided biopsy, US-guided vascular puncture, cone-beam CT drainage, and fluoroscopy-guided lumbar puncture, as well as using the parallax effect to determine relative position at fluoroscopy. Phantoms are a valuable training tool, although it is important to consider the teaching audience when choosing or creating a model. For novices, a range of inexpensive low-fidelity gelatin-based phantoms can be used to train core skills in image-guided procedures. The online slide presentation from the RSNA Annual Meeting is available for this article. ©RSNA, 2021.

Ultrasound evaluation of the radial artery in young adults — A pilot study

The radial artery is a vessel frequently used in various medical procedures which carry a risk of complications. One such method used to minimize the number of complications is a profound knowledge of the artery’s diameter, which allows for appropriate selection of an instrument to use for puncture. The purpose of this study is to determine the diameter of the radial artery and its depth from the skin surface in young adults. Material and methods96 volunteers participated in the study. The average age of the volunteers was 20.43 years. All participants underwent a B-mode ultrasonography to measure the distal radial artery’s diameter. Certified anthropometric instruments were used to determine the relation between the artery diameter and the selected basic anthropometric parameters. ResultsThe mean right arterial diameter for the entire examined population at the level of the styloid process was mean 1.42 (SD 0.26) mm and its distance to the skin was mean 4.00 (SD1.20) mm. Statistical analysis revealed the presence of moderate positive relationship between the diameter of the radial artery and body weight and between the diameter of the radial artery and BMI. A weak correlation between the artery diameter and the width of the wrist was also present. ConclusionIn the present work, we aimed to determine the dimensions of the distal section of the radial artery in young people free from symptoms of cardiovascular diseases. The obtained initial study results advise selecting instruments for vascular puncture individually, with special attention paid to slender people with slim wrists.

A randomized double-blinded controlled trial comparing ultrasound-guided versus conventional injection for caudal block in children undergoing infra-umbilical surgeries.

Background and Aims:Caudal epidural block is widely used in pediatric surgeries to provide intraoperative and postoperative analgesia in infra-umbilical surgeries. The conventional technique involves the risk of multiple punctures and other complications such as dural puncture, vascular puncture, and intraosseous injection.Material and Methods:Around 106 children aged between 6 months to 10 years belonging to ASA class I-II scheduled for elective infra-umbilical surgeries were included after obtaining written informed consent from parents/guardians. All children were randomized into two groups: ultrasound-guided (Group U) or conventional caudal group (Group C). All were premedicated with oral midazolam and inhalational induction was done with oxygen and 6–8% sevoflurane. Caudal block of 1 mL/kg of 0.125% bupivacaine was administered in both groups. The primary outcome assessed was 1st puncture success rate and the secondary outcomes assessed were number of skin punctures, block performing time, and block success rate.Results:Group U had a higher first puncture success rate (P = 0.001) than Group C (90.6% v/s 64.2%) and was statistically significant. The number of punctures were significantly less (P = 0.01) in Group U (1.09 ± 0.295) than Group C (1.45 ± 0.667). Block performing time was significantly higher (P = 0.0005) in Group U (53.19 ± 10.97 s) than Group C (30.34 ± 7.34 s). There was no difference in the overall block success rate between the groups (98.1% v/s 100%).Conclusion:Ultrasound-guided caudal injection increases the first puncture success rate and decreases the number of punctures required compared to conventional caudal block in pediatric infra-umbilical surgeries.

Stellate ganglion block combined with intra-arterial treatment: a "one-stop shop" for cerebral vasospasm after aneurysmal subarachnoid hemorrhage-a pilot study.

Delayed cerebral ischemia (DCI) is a frequent cause of morbidity and mortality in patients with cerebral vasospasm (CV) following aneurysmal subarachnoid hemorrhage (aSAH). Refractory CV remains challenging to treat and often leads to permanent deficits and death despite aggressive therapy. We hereby report the feasibility and safety of stellate ganglion block (SGB) performed with a vascular roadmap-guided technique to minimize the risk of accidental vascular puncture and may be coupled to a diagnostic or therapeutic cerebral angiography. In addition to a detailed description of the technique, we performed a retrospective analysis of a series of consecutive patients with refractory CV after aSAH that were treated with adjuvant roadmap-guided SGB. Clinical outcomes at discharge are reported. Nineteen SGB procedures were performed in 10 patients, after failure of traditional hemodynamic and endovascular treatments. Each patient received 1 to 3 SGB, usually interspaced by 24 h. In 4 patients, an indwelling microcatheter for continuous infusion was inserted. First SGB occurred on average 7.3 days after aSAH. SGB was coupled to intra-arterial nimodipine infusion or balloon angioplasty in 9 patients. SGB was technically successful in all patients. There were no technical or clinical complications. Adjuvant SGB may be coupled to endovascular therapy to treat refractory cerebral vasopasm within the same session. To guide needle placement, using a roadmap of the supra-aortic arteries may decrease the risk of complications. More prospective data is needed to evaluate the therapeutic efficacy, durability, and safety of SGB compared with the established standard of care.

First report of cDNA clone-launched infection of maize plants with the polerovirus maize yellow mosaic virus (MaYMV)

An East African isolate of the maize-associated polerovirus, maize yellow mosaic virus (MaYMV) was previously shown to cause leaf reddening on singly infected maize plants (Zea mays). Here we describe the construction of a full-length infectious clone of an East African isolate and, for the first time, show infectivity of clone-derived transcripts in the primary host, maize, through vascular puncture inoculation (VPI), as well as in the dicotyledonous research model plant species, Nicotiana benthamiana, through agrobacterium inoculation. Characteristic leaf reddening symptoms were observed in a subset of maize plants inoculated with clone-derived transcripts, and infection was confirmed by RT-PCR and Northern blot analyses. In N. benthamiana plants, infections were entirely asymptomatic even at high virus titers, as was also reported for the cloned Chinese isolate. In this study, however, we demonstrated that N. benthamiana can serve as a clone launching platform for maize infection, as VPI of sap of infected N. benthamiana plants into maize kernels resulted in infection and the typical red leaf symptoms. We further demonstrated that the cloned East African isolate virus was aphid transmissible to maize, with experimental transmission rates up to 97 %, comparable to that shown previously for the native virus. Interestingly, our data additionally showed a definitive correlation of leaf reddening symptoms with increased expression of chalcone synthase, thus suggesting upregulation of the flavonoid biosynthesis pathway as the molecular basis for symptom induction in maize. As the first report of experimental infection of maize with transcripts from a cloned polerovirus, this work constitutes a breakthrough for studies on molecular maize-polerovirus-aphid interactions.

Ultrasound Guided Serratus Anterior Plane Block versus Thoracic Epidural Analgesia in Breast Surgery

Background: Breast Surgery is becoming more and more common. Patients are often middle-aged women and with high public awareness around issues of breast cancer. The numbers are increasing. Breast surgery is an exceedingly common procedure and associated with an increased incidence of acute and chronic pain. Regional anesthesia techniques may improve postoperative analgesia for patients undergoing breast surgery. Objective: To assess the efficacy and safety of ultrasound-guided serratus anterior plane block (SAPB) compared with thoracic epidural analgesia (TEA) for breast surgery. Patients and methods: This is a prospective randomized clinical study done at Aswan University Hospitals. The present study was conducted on sixty female patients ASA I-II, their ages ranged from 20-50 years and scheduled for unilateral breast surgery. The patients were allocated randomly into three groups (n=20 each) according to type of regional anesthesia administrated. Results: There was no significant difference between the studied groups in age, body weight, height and BMI. VAS pain scores throughout the first 24 hrs postoperative showed that there was highly statistically significant decrease in VAS in immediate till 6 hrs postoperative in SAPB group (VAS in group C was less than in groups A and B, P-value < 0.001). As regard to side effects, no complications in the studied groups were recorded such as pneumothorax, vascular puncture, or local anesthetic toxicity. Conclusion: Serratusanterior plane blockmaintained hemodynamic stability as compared to TE and it produced low pain scores and less total morphine consumption in the early postoperative period after unilateral breast cancer surgery. These advantages, suggest the usefulness of SAPB especially in outpatient surgery.

The role of peripheral nerve stimulation in the era of ultrasound-guided regional anaesthesia.

With the widespread use of ultrasound for localising nerves during peripheral nerve blockade, the value of electrical nerve stimulation of evoked motor responses has been questioned. Studies continue to show that, compared with nerve stimulation, ultrasound guidance alone leads to: significantly improved block success; decreased need for rescue analgesia; decreased procedural pain; and lower rates of vascular puncture. Nerve stimulation combined with ultrasound does also not appear to improve block success rates, apart from those blocks where the nerves are challenging to view, such as the obturator nerve. The role of nerve stimulation has changed in the last 15years from a technique to locate nerves to that of an adjunct to ultrasound. Nerve stimulation can serve as a monitor against needle-nerve contact and may be useful in avoiding nerves that are in the needle trajectory during specific ultrasound guided techniques. Nerve stimulation is also a useful adjunct in teaching novices ultrasound-guided regional anaesthesia, especially when the position and or appearance of nerves may be variable. In this review, the changing role of nerve stimulation in contemporary regional anaesthetic practice is presented and discussed.

Combined short- and long-axis method for internal jugular vein catheterization in premature newborns: A randomized controlled trial.

Rapid central venous catheterization is critical for the rescue and perioperative management of premature infants requiring surgery. Ultrasound-guided dynamic needle tip positioning (DNTP) has been widely used as a very effective technique, especially in paediatric vascular puncture and catheterization. However, for low-weight premature newborns, central vein catheterization still poses greater difficulties for paediatricians and paediatric anaesthesiologists. This prospective randomized control study aimed to evaluate the efficacy of combined short- and long-axis (CSLA) internal jugular vein catheterization for premature newborns in comparison with the DNTP technique. A total of 90 premature newborns (gestational age <37weeks and <28days after birth) who were scheduled for surgery were included in this study. All enrolled premature newborns were randomly divided into two groups (n=45): the CSLA group and the DNTP group. We compared the first-puncture success rate, total success rate, procedure time, number of needle passes, occurrence of complications and other outcome measures between the two groups. The two groups (n=45 per group) were similar in sex, gestational age, weight, mean arterial blood pressure, and vein-related measurements of the internal jugular vein. Total success was achieved in 43 (95.6%) and 36 (80.0%) patients in the CSLA and DNTP groups respectively. Compared with the DNTP group, the CSLA group showed a significantly higher first-attempt success rate (71.1% vs 46.7%, χ2 =5.5533, P=.0184) and significantly fewer needle passes (1.0[1.0-2.0] vs 2.0[1.0-3.0], χ2 =-2.6094, P=.0091). There was no significant difference between the groups in the procedure time (368[304-573] vs 478[324-79]s, Z=-1.7690, P=.0769). Complications occurred in both groups, but the incidence was significantly lower in the CSLA group than in the DNTP group (6.7% vs 22.2%, χ2 =4.4056, P=.0358). Ultrasound-guided internal jugular vein catheterization by the CSLA method is effective and safe. The CSLA method may be superior to the DNTP technique in premature newborns.

Engineering Maize rayado fino virus for virus-induced gene silencing.

Maize rayado fino virus (MRFV) is the type species of the genus Marafivirus in the family Tymoviridae. It infects maize (Zea mays), its natural host, to which it is transmitted by leafhoppers including Dalbulus maidis and Graminella nigrifrons in a persistent‐propagative manner. The MRFV monopartite RNA genome encodes a precursor polyprotein that is processed into replication‐associated proteins. The genome is encapsidated by two carboxy co‐terminal coat proteins, CP1 and CP2. Cloned MRFV can be readily transmitted to maize by vascular puncture inoculation (VPI), and such virus systems that can be used in maize are valuable to examine plant gene function by gene silencing. However, the efficacy of marafiviruses for virus‐induced gene silencing (VIGS) has not been investigated to date. To this end, MRFV genomic loci were tested for their potential to host foreign insertions without attenuating virus viability. This was done using infectious MRFV clones engineered to carry maize phytoene desaturase (PDS) gene fragments (ZmPDS) at various genomic regions. Several MRFV‐PDS constructs were generated and tested for infectivity and VIGS in maize. This culminated in identification of the helicase/polymerase (HEL/POL) junction as a viable insertion site that preserved virus infectivity, as well as several sites at which sequence insertion caused loss of virus infectivity. Transcripts of viable constructs, carrying PDS inserts in the HEL/POL junction, induced stable local and systemic MRFV symptoms similar to wild‐type infections, and triggered PDS VIGS initiating in veins and spreading into both inoculated and noninoculated leaves. These constructs were remarkably stable, retaining inserted sequences for at least four VPI passages while maintaining transmissibility by D. maidis. Our data thus identify the MRFV HEL/POL junction as an insertion site useful for gene silencing in maize.