Ultrasound-triggered local anaesthesia.
Ontology highlight
ABSTRACT:
SUBMITTER: Rwei AY
PROVIDER: S-EPMC5687284 | biostudies-literature | 2017
REPOSITORIES: biostudies-literature
Publications
Ultrasound-triggered local anaesthesia.
Rwei Alina Y AY Paris Juan L JL Wang Bruce B Wang Weiping W Axon Christopher D CD Vallet-Regí María M Langer Robert R Kohane Daniel S DS
Nature biomedical engineering 20170809
On-demand relief of local pain would allow patients to control the timing, intensity and duration of nerve block in a safe and non-invasive manner. Ultrasound would be a suitable trigger for such a system, as it is in common clinical use and can penetrate deeply into the body. Here, we demonstrate that ultrasound-triggered delivery of an anaesthetic from liposomes allows the timing, intensity and duration of nerve block to be controlled by ultrasound parameters. On insonation, the encapsulated s ...[more]
Similar Datasets
Project description:BackgroundFour-dimensional (4D) ultrasound scanning (3D real-time mode) can improve the orientation of the anatomy of the area of interest and navigation by controlling the needle position. The objectives of this study were to identify the optimal technique for navigation and to assess clinically the efficacy of 4D ultrasound navigation for epidural anaesthesia at lower thoracic and lumbar levels.DesignSingle-centre case series study was performed.MethodsSixteen patients were included. First, conventional 2D scanning was performed, followed by 4D reconstruction, and the basic tissues with high acoustic impedance (bone structures) and available acoustic windows were determined. Movement of the needle was controlled on the sagittal plane in 2D mode and at the same time in 4D mode (3D real-time mode). To improve the visibility of the needle, the 3D reconstruction was rotated during manipulation.ResultsThe 4D scanning mode provided 100 % visibility of compact bone tissues and 93 % visibility of the posterior complex. Needle visualisation strongly depended on the rotation of the reconstructed image with the sensor remaining motionless. The needle was redirected in one patient (7 %) because it was in contact with the vertebral lamina. Dilation of the epidural space during saline injection was observed in five patients (36 %). A change in the puncture level was not required any patients; no complications associated with epidural puncture were observed.ConclusionsUltrasound navigation in 4D could improve epidural anaesthesia due to the enhanced spatial orientation of the operator. The technique of "position contrast" should be used for reliable needle visualisation.
| S-EPMC4504855 | biostudies-literature
Project description:Hydrogels are formed using various triggers, including light irradiation, pH adjustment, heating, cooling, or chemical addition. Here, a new method for forming hydrogels is introduced: ultrasound-triggered enzymatic gelation. Specifically, ultrasound is used as a stimulus to liberate liposomal calcium ions, which then trigger the enzymatic activity of transglutaminase. The activated enzyme catalyzes the formation of fibrinogen hydrogels through covalent intermolecular crosslinking. The catalysis and gelation processes are monitored in real time and both the enzyme kinetics and final hydrogel properties are controlled by varying the initial ultrasound exposure time. This technology is extended to microbubble-liposome conjugates, which exhibit a stronger response to the applied acoustic field and are also used for ultrasound-triggered enzymatic hydrogelation. To the best of the knowledge, these results are the first instance in which ultrasound is used as a trigger for either enzyme catalysis or enzymatic hydrogelation. This approach is highly versatile and can be readily applied to different ion-dependent enzymes or gelation systems. Moreover, this work paves the way for the use of ultrasound as a remote trigger for in vivo hydrogelation.
| S-EPMC7180077 | biostudies-literature
Project description:ObjectivesTo determine whether administration of local anaesthetic at the site of skin incision during open lacrimal drainage surgery under general anaesthesia alters the total dosage of anaesthetic drugs required during total intravenous anaesthesia (TIVA), and whether it alters postoperative pain and recovery.Study designMasked comparison of a randomized, two-group interventional study.Patients and methodsPatients undergoing unilateral external dacryocystorhinostomy under total intravenous general anaesthesia were recruited from the lacrimal service at Moorfields Eye Hospital between September 2012 and February 2014. The patients were randomised to receive, after induction and stabilisation of general anaesthesia, infiltration of the ipsilateral paranasal tissues with 2.5 ml of 0.5% bupivacaine with 1:100000 epinephrine ("treatment" group), or a sham injection ("control" group); the infiltration was performed about 7 min prior to the skin incision. The infusion rates for propofol and remifentanil were adjusted to maintain a steady intra-operative mean blood pressure of 55-70 mmHg and BIS score of 40-60%. The time taken for extubation of the patient after cessation of TIVA was recorded, and postoperative pain scores (on a Likert scale from 0-10) were taken at regular intervals after extubation. The average intra-operative mean blood pressures, total drug usage, extubation time and pain scores for each of the two groups were compared using two-tail Student's t-testing and Wilcoxon rank sum testing.ResultsThere were 12 patients (7 female; 58%) in the treatment group and 11 (7 female; 64%) in the control group, with similar average age at surgery (59 years treatment, 53 years control; p = 0.38) The average operative time was 45 min in the treatment group (median 42, range 30-55) and 47 min (median 45; range 37-61) in the control group (p = 0.52). The mean dosage of propofol required to maintain satisfactory GA was significantly less in the "treatment" group (89.8 mcg/kg/min) as compared to the "control" group (mean 126 mcg/kg/min) (p = 0.0007). Likewise, remifentanil dosage was significantly less in the "treatment" group (100 ng/kg/min) as compared to controls (259 ng/kg/min) (p = 0.00007). The mean non-invasive blood pressure was consistently lower during surgery in the "treated" group, and showed less intra-operative variation. After surgery, the patients receiving LA had a significantly shorter extubation time (mean time 6.0 min in "treated" group, 12.1 min in "controls"; P < 0.0002) and also significantly lower pain scores at 10, 30, 60, 120 and 180 min after extubation (p < 0.01, p < 0.01, p < 0.01, p < 0.01 and p < 0.05, respectively).ConclusionsIpsilateral infiltration of local anaesthesia containing epinephrine in the paranasal tissues just prior to open dacryocystorhinostomy under total intravenous anaesthesia is associated with a 28% reduction in mean propofol usage, and a 61% reduction in remifentanil usage. LA usage during GA also produces improved and less variable intra-operative mean blood pressures, a significantly shorter extubation time and significantly lower postoperative pain scores.
| S-EPMC6460689 | biostudies-literature
Project description: Not available
| S-EPMC4392228 | biostudies-literature
Project description:BackgroundPatients who have severe narrowing at or near the origin of the internal carotid artery as a result of atherosclerosis have a high risk of ischaemic stroke ipsilateral to the arterial lesion. Previous trials have shown that carotid endarterectomy improves long-term outcomes, particularly when performed soon after a prior transient ischaemic attack or mild ischaemic stroke. However, complications may occur during or soon after surgery, the most serious of which is stroke, which can be fatal. It has been suggested that performing the operation under local anaesthesia, rather than general anaesthesia, may be safer. Therefore, a prospective, randomised trial of local versus general anaesthesia for carotid endarterectomy was proposed to determine whether type of anaesthesia influences peri-operative morbidity and mortality, quality of life and longer term outcome in terms of stroke-free survival.Methods/designA two-arm, parallel group, multicentre randomised controlled trial with a recruitment target of 5000 patients. For entry into the study, in the opinion of the responsible clinician, the patient requiring an endarterectomy must be suitable for either local or general anaesthesia, and have no clear indication for either type. All patients with symptomatic or asymptomatic internal carotid stenosis for whom open surgery is advised are eligible. There is no upper age limit. Exclusion criteria are: no informed consent; definite preference for local or general anaesthetic by the clinician or patient; patient unlikely to be able to co-operate with awake testing during local anaesthesia; patient requiring simultaneous bilateral carotid endarterectomy; carotid endarterectomy combined with another operation such as coronary bypass surgery; and, the patient has been randomised into the trial previously. Patients are randomised to local or general anaesthesia by the central trial office. The primary outcome is the proportion of patients alive, stroke free (including retinal infarction) and without myocardial infarction 30 days post-surgery. Secondary outcomes include the proportion of patients alive and stroke free at one year; health related quality of life at 30 days; surgical adverse events, re-operation and re-admission rates; the relative cost of the two methods of anaesthesia; length of stay and intensive and high dependency bed occupancy.Trial registrationCurrent Controlled Trials ISRCTN00525237.
| S-EPMC2413207 | biostudies-literature
Project description:ObjectivesWe conducted a systematic review and meta-analysis to identify the potential favourable effects of local anaesthesia plus sedation (LAS) compared with general anaesthesia (GA) in transcatheter aortic valve implantation (TAVI).MethodsElectronic databases (PubMed/Medline, Embase, Cochrane Central Register of Controlled Trials) and the reference lists of eligible publications were screened for randomised controlled trials (RCTs) and observational studies published between 1 January 2006 and 26 June 2016 that compare LAS to GA in an adult study population undergoing TAVI. We conducted study quality assessments using the Cochrane risk of bias tool and structured the review according to PRISMA. A meta-analysis calculating the pooled risk ratios (RRs) and mean differences (MDs) with 95% confidence intervals (CIs) under the assumption of a random-effects model was performed. Statistical heterogeneity was evaluated using the I² statistic and Cochran's Q-test.ResultsAfter database screening, one RCT and 19 observational studies were included in the review. We found no differences between LAS and GA in terms of 30-day mortality, in-hospital mortality and other endpoints that addressed safety and complication rates. LAS was associated with a shorter ICU and hospital stay and with lower rates of catecholamine administration and red blood cell transfusion. New pacemaker implantations occurred more frequently under LAS. The overall conversion rate from LAS to GA was 6.2%.ConclusionFor TAVI, both LAS and GA are feasible and safe. LAS may have some benefits such as increased haemodynamic stability and shorter hospital and ICU stays, but it does not impact 30-day mortality. Since there is a paucity of randomised trial data and the findings are mainly based on observational study data, this review should be considered as a hypothesis-generating article for subsequent RCTs that are required to confirm the potential favourable effects we detected for LAS.Registration numberCRD42016048398 (PROSPERO).
| S-EPMC5623571 | biostudies-literature
Project description:The aim of this investigation was to evaluate the effects of local anaesthesia on nerve growth factor (NGF) induced masseter hyperalgesia. Healthy participants randomly received an injection into the right masseter muscle of either isotonic saline (IS) given as a single injection (n?=?15) or an injection of NGF (n?=?30) followed by a second injection of lidocaine (NGF?+?lidocaine; n?=?15) or IS (NGF?+?IS; n?=?15) in the same muscle 48 h later. Mechanical sensitivity scores of the right and left masseter, referred sensations and jaw pain intensity and jaw function were assessed at baseline, 48 h after the first injection, 5 min after the second injection and 72 h after the first injection. NGF caused significant jaw pain evoked by chewing at 48 and 72 h after the first injection when compared to the IS group, but without significant differences between the NGF?+?lidocaine and NGF?+?IS groups. However, the mechanical sensitivity of the right masseter 5 min after the second injection in the NGF?+?lidocaine group was significantly lower than the second injection in the NGF?+?IS and was similar to the IS group. There were no significant differences for the referred sensations. Local anaesthetics may provide relevant information regarding the contribution of peripheral mechanisms in the maintenance of persistent musculoskeletal pain.
| S-EPMC7508842 | biostudies-literature
Project description:Ultrasonic imaging is a widely used tool for detection, localisation and characterisation of material inhomogeneities with important applications in many fields. This task is particularly challenging when imaging in a complex medium, where the ultrasonic wave is scattered by the material microstructure, preventing detection and characterisation of weak targets. Fundamentally, the maximum information that can be experimentally obtained from each material region consists of a set of reflected signals for different incident waves. However, these data are not directly accessible from the raw measurements, which represent a superposition of reflections from all scatterers in the medium. Here we show, that a complete set of transmitter-receiver data encodes sufficient information in order to achieve full spatio-temporal separation of transmitter-receiver data, corresponding to different local scattering areas. We show that access to the local scattering data can provide valuable benefits for many applications. More importantly, this technique enables fundamentally new approaches, exploiting the angular distribution of the scattering amplitude and phase of each local scattering region. Here we demonstrate how the local scattering directivity can be used to build the local scattering image, releasing the full potential and richness of the transmit-receive data. As a proof of concept, we demonstrate the detection of small inclusions in various highly scattering materials using numerical and experimental examples. The described principles are very general and can be applied to any research field where the phased array technology is employed.
| S-EPMC7806797 | biostudies-literature
Project description:Because of their size (1-10 μm), microbubble-based drug delivery agents suffer from confinement to the vasculature, limiting tumor penetration and potentially reducing the drug efficacy. Nanobubbles (NBs) have emerged as promising candidates for ultrasound-triggered drug delivery because of their small size, allowing drug delivery complexes to take advantage of the enhanced permeability and retention effect. In this study, we describe a simple method for production of nested-nanobubbles (Nested-NBs) by encapsulation of NBs (∼100 nm) within drug-loaded liposomes. This method combines the efficient and well-established drug-loading capabilities of liposomes while utilizing NBs as an acoustic trigger for drug release. Encapsulation was characterized using transmission electron microscopy with an encapsulation efficiency of 22 ± 2%. Nested-NBs demonstrated echogenicity using diagnostic B-mode imaging, and acoustic emissions were monitored during high-intensity focused ultrasound (HIFU) in addition to monitoring of model drug release. Results showed that although the encapsulated NBs were destroyed by pulsed HIFU [peak negative pressure (PNP) 1.54-4.83 MPa], signified by loss of echogenicity and detection of inertial cavitation, no model drug release was observed. Changing modality to continuous wave (CW) HIFU produced release across a range of PNPs (2.01-3.90 MPa), likely because of a synergistic effect of mechanical and increased thermal stimuli. Because of this, we predict that our NBs contain a mixed population of both gaseous and liquid core particles, which upon CW HIFU undergo rapid phase conversion, triggering liposomal drug release. This hypothesis was investigated using previously described models to predict the existence of droplets and their phase change potential and the ability of this phase change to induce liposomal drug release.
| S-EPMC7333229 | biostudies-literature
Project description:BackgroundCase series and a post hoc subgroup analysis of a large randomized trial have suggested a potential benefit in treating ruptured abdominal aortic aneurysms (rAAAs) using endovascular aneurysm repair (EVAR) with local anaesthesia (LA) rather than general anaesthesia (GA). The uptake and outcomes of LA in clinical practice remain unknown.MethodsThe UK National Vascular Registry was interrogated for patients presenting with rAAA managed with EVAR under different modes of anaesthesia between 1 January 2014 and 31 December 2016. The primary outcome was in-hospital mortality. Secondary outcomes included: the number of centres performing EVAR under LA; the proportion of patients receiving this technique; duration of hospital stay; and postoperative complications.ResultsSome 3101 patients with rAAA were treated in 72 hospitals during the study: 2306 underwent on open procedure and 795 had EVAR (LA, 319; GA, 435; regional anaesthesia, 41). Overall, 56 of 72 hospitals (78 per cent) offered LA for EVAR of rAAA. Baseline characteristics and morphology were similar across the three EVAR subgroups. Patients who had surgery under LA had a lower in-hospital mortality rate than patients who received GA (59 of 319 (18·5 per cent) versus 122 of 435 (28·0 per cent)), and this was unchanged after adjustment for factors known to influence survival (adjusted hazard ratio 0·62, 95 per cent c.i. 0·45 to 0·85; P = 0·003). Median hospital stay and postoperative morbidity from other complications were similar.ConclusionThe use of LA for EVAR of rAAA has been adopted widely in the UK. Mortality rates appear lower than in patients undergoing EVAR with GA.
| S-EPMC6519219 | biostudies-literature