Anesthetic Spread Research Articles

Evolution of transversus abdominis plane infiltration techniques for postsurgical analgesia following abdominal surgeries

Transversus abdominis plane (TAP) infiltration is a regional anesthesia technique that has been demonstrated to be effective for management of postsurgical pain after abdominal surgery. There are several different clinical variations in the approaches used for achieving analgesia via TAP infiltration, and methods for identification of the TAP have evolved considerably since the landmark-guided technique was first described in 2001. There are many factors that impact the analgesic outcomes following TAP infiltration, and the various nuances of this technique have led to debate regarding procedural classification of TAP infiltration. Based on our current understanding of fascial and neuronal anatomy of the anterior abdominal wall, as well as available evidence from studies assessing local anesthetic spread and cutaneous sensory block following TAP infiltration, it is clear that TAP infiltration techniques are appropriately classified as field blocks. While the objective of peripheral nerve block and TAP infiltration are similar in that both approaches block sensory response in order to achieve analgesia, the technical components of the two procedures are different. Unlike peripheral nerve block, which involves identification or stimulation of a specific nerve or nerve plexus, followed by administration of a local anesthetic in close proximity, TAP infiltration involves administration and spread of local anesthetic within an anatomical plane of the surgical site.

Hemodynamic Changes During Spinal Anesthesia For Elective Cesarean Section With Hyperbaric Bupivacaine: Effect Of Volume And Concentration

Background: Spinal anesthesia for cesarean section with hyperbaric Bupivacaine is widely used. The course of the procedure is frequently troubled by hemodynamic instability that is determined by the level of spinal block and this in turn depends on the spread of the local anesthetic within the CSF. By fixing the dose of the local anesthetic any increase in its volume leads to a decrease in its concentration because these factors are closely related to each other and they can affect the spread of the local anesthetic. Objective: To compare between large volume but lower concentration (4 ml of 0.25%) and small volume but higher concentration (2 ml of 0.5% ) of hyperbaric Bupivacaine solutions used for spinal anesthesia for elective cesarean section in respect to hemodynamic changes. Method: A clinical interventional study was Performed at Al-Zahra'a Teaching Hospital (Najaf ) of 18th Jun.-18th Jul. 2013. Forty patients scheduled for elective cesarean section were randomly selected and randomly divided into two equal groups (A and B). Both groups received hyperbaric Bupivacaine via intrathecal route, group (A) received 4 ml of 0.25% solution while group (B) received 2 ml of 0.5% solution. Hemodynamic variables (blood pressure and heart rate) were recorded throughout the time of anesthesia. Data was analyzed by using SPSS version 20. Results: There was no significant difference in the incidence of hypotension (P value=1.0) between the two groups while the incidence of bradycardia was equal between the two groups (10%) but there was a need for significantly higher average dose of Ephedrine that was used to treat hypotension in group (A) than in group (B) (P value=0.49%) reflecting more severe hypotension in group (A) than group (B). Conclusion: we conclude that the volume factor has more influence than the concentration on blood pressure with regard to hyperbaric intrathecal Bupivacaine solutions used for elective cesarean section. Recommendation: the use of smaller volume but higher concentration of intrathecal Bupivacaine is advisable in elective cesarean section.

Three-dimensional ultrasound imaging.

Ultrasound guidance is frequently utilized for needle placement and observation of local anesthetic spread when performing peripheral nerve blocks. Although there is evidence that ultrasound technology can reduce complications, there are limitations to 2-dimensional (2-D) ultrasound. Three-dimensional (3-D) and especially real-time 3-D (4-D) ultrasound may allow for optimized and well tolerated needle positioning and enhanced observation of local anesthetic spread around the target structure. This article reviewed the current literature regarding the use of 3-D and 4-D ultrasound technology in a regional anesthesia setting. Several investigations have utilized 3-D ultrasound as a tool to study anatomical spatial relationships, evaluate local anesthetic spread, or optimize nerve block needle or catheter positioning. However, this was mostly achieved by retrospectively generating a 3-D image after the performance of the actual nerve blocks or studying anatomy on volunteers. There are only a few case reports available demonstrating the feasibility of 4-D ultrasound for nerve block performance. At present, there are limited data regarding the use of 3-D ultrasound and a complete lack of randomized controlled clinical trials evaluating the potential benefits of real-time 3-D (4-D) ultrasound. This may be in part due to technical limitations associated with these techniques.

Ultrasound guided axillary brachial plexus plexus block. Part 1--basic sonoanatomy.

Axillary brachial plexus block is one of the most popular and widely used approaches for brachial plexus blocks. Its main advantages are its versatility and high safety. Brachial block facilitates analgesia for the distal arm, elbow, forearm and hand. Numerous upper limb procedures, particularly orthopedic ones, can be carried out under axillary block. Axillary block is well suited for the ultrasound-guided technique. Because the brachial plexus in the axillary region is located superficially, the nerves, block needle, and local anesthetic spread are all relatively easy to visualize. A high-frequency linear probe can be used during block procedure, so the quality and resolution of the ultrasound images are excellent. An important feature of the axillary approach is its high level of safety. In the axillary area, there are no anatomical structures other than vessels, to which damage during block placement could pose a risk for the patient. For this reason, axillary block is one of the techniques that are recommended for learning ultrasound-guided regional anesthesia. This paper summarizes anatomical fundamentals and provides basic sonoanatomic knowledge that is essential for successful ultrasound-guided axillary block.

A randomised controlled trial of the effect of a head-elevation pillow on intrathecal local anaesthetic spread in caesarean section

BackgroundA head-elevation pillow places a patient in a ramped posture, which maximises the view of the larynx during laryngoscopy, particularly in obese parturients. In our institution an elevation pillow is used pre-emptively for neuraxial anaesthesia. We hypothesised that head-elevation may impair cephalad spread of local anaesthetic before caesarean section resulting in a lower block or longer time to achieve a T6 level. We aimed to investigate the effect of head-elevation on spread of intrathecal local anaesthetics during anaesthesia for caesarean section. MethodsOne-hundred parturients presenting for caesarean section under combined spinal-epidural anaesthesia were randomised to either the standard supine position with lateral displacement or in the supine position with lateral displacement on an head-elevation pillow. Each patient received intrathecal hyperbaric bupivacaine 11mg, morphine 100μg and fentanyl 15μg. Patients were assessed for adequacy of sensory block (T6 or higher) at 10min. ResultsSensory block to T6 was achieved within 10min in 65.9% of parturients in the Elevation Pillow Group compared to 95.7% in the Control Group (P<0.05). Compared to the Control Group, patients in the Elevation Pillow Group had greater requirements for epidural supplementation (43.5% vs 2.1%, P<0.001) or conversion to general anaesthesia (9.3% vs 0%, P<0.04). ConclusionsUse of a ramped position with an head-elevation pillow following injection of the intrathecal component of a combined spinal-epidural anaesthetic for scheduled caesarean section was associated with a significantly lower block height at 10min.

Ophthalmic regional blocks: management, challenges, and solutions.

In the past decade ophthalmic anesthesia has witnessed a major transformation. The sun has set on the landscape of ophthalmic procedures performed under general anesthesia at in-hospital settings. In its place a new dawn has ushered in the panorama of eye surgeries conducted under regional and topical anesthesia at specialty eye care centers. The impact of the burgeoning geriatric population is that an increasing number of elderly patients will present for eye surgery. In order to accommodate increased patient volumes and simultaneously satisfy administrative initiatives directed at economic frugality, administrators will seek assistance from anesthesia providers in adopting measures that enhance operating room efficiency. The performance of eye blocks in a holding suite meets many of these objectives. Unfortunately, most practicing anesthesiologists resist performing ophthalmic regional blocks because they lack formal training. In future, anesthesiologists will need to block eyes and manage common medical conditions because economic pressures will eliminate routine preoperative testing. This review addresses a variety of topical issues in ophthalmic anesthesia with special emphasis on cannula and needle-based blocks and the new-generation antithrombotic agents. In a constantly evolving arena, the sub-Tenon’s block has gained popularity while the deep angulated intraconal (retrobulbar) block has been largely superseded by the shallower extraconal (peribulbar) approach. Improvements in surgical technique have also impacted anesthetic practice. For example, phacoemulsification techniques facilitate the conduct of cataract surgery under topical anesthesia, and suture-free vitrectomy ports may cause venous air embolism during air/fluid exchange. Hyaluronidase is a useful adjuvant because it promotes local anesthetic diffusion and hastens block onset time but it is allergenic. Ultrasound-guided eye blocks afford real-time visualization of needle position and local anesthetic spread. An advantage of sonic guidance is that it may eliminate the hazard of globe perforation by identifying abnormal anatomy, such as staphyloma.

Thoracolumbar interfascial plane (TLIP) block: a pilot study in volunteers.

Regional anesthesia has been shown to improve outcomes in several recent studies. The transversus abdominis plane (TAP) block provides anesthesia to the abdominal wall by introducing local anesthetic to the ventral rami of the thoracolumbar nerves. This work quantifies the area of anesthesia obtained after performing the novel thoracolumbar interfascial plane block (analogous to the TAP block but intended for the back) which targets the sensory component of the dorsal rami of the thoracolumbar nerves. Ten participants underwent bilateral ultrasound-guided injections of 0.2% ropivacaine 20 mL into the fascial plane between the multifidus and longissimus muscles. After five and 20 min, respectively, the area of anesthesia was plotted on the participant's back. Anesthesia was defined as loss of point discrimination to pinprick. Participants reported a mean (SD) area of anesthesia surrounding the needle injection site of 137.4 (71.0) cm(2) and 217.0 (84.7) cm(2) at five and 20 min after injection, respectively. The mean (SD) cephalad and caudal spread of local anesthetic from the site of injection was 6.5 (1.8) cm and 3.9 (1.2) cm, respectively. There were no complications or adverse events reported. This report shows that a reproducible area of anesthesia can be obtained by ultrasound-guided injection of local anesthetic in the fascial plane between the multifidus and longissimus muscles of the thoracolumbar spine. The area of anesthesia consistently covered the midline and had a predictable spread. This project was registered with clinicaltrials.gov (NCT02297191).

Postural change from lateral to supine is an important mechanism enhancing cephalic spread after injection of intrathecal 0.5% plain bupivacaine for cesarean section

BackgroundSpinal anesthesia is widely used for cesarean section, but the factors that affect the spread of the block in pregnant patients are still not fully explained. This study was designed to investigate the effect of postural changes on sensory block level. MethodsThirty patients scheduled for elective cesarean section under combined spinal–epidural anesthesia were randomly allocated into three groups. After intrathecal injection of 0.5% plain bupivacaine 7.5mg, patients in group S were immediately placed in the supine position with left tilt, patients in group L5 were kept lateral for 5min and then turned to the supine position with left tilt, and patients in group L10 were kept lateral for 10min and then turned to the supine position with left tilt. ResultsAt 5min, median cephalad level of sensory block was lower in groups L5 and L10 compared with group S (corrected P<0.001); at 10min, median cephalad sensory block level was lower in group L10 compared with group S (corrected P<0.001) and group L5 (corrected P<0.001), and lower in group L5 compared with group S (corrected P=0.033); at 15 min, median cephalad level of sensory block was lower in group L10 compared with group S (corrected P=0.003) and group L5 (corrected P=0.015). ConclusionsIn our population, using 0.5% plain bupivacaine 7.5mg, postural change from the lateral position to the supine position is an important mechanism enhancing cephalic spread of spinal anesthesia during late pregnancy.

Ultrasound-assisted periconal ocular blockade in rabbits

ObjectiveThis study aimed to evaluate the benefit and specifically the feasibility of using ultrasound in ophthalmologic periconal block, and the occurrence of complications. Study designProspective experimental study. AnimalsTen healthy New Zealand White rabbits (6–8 months of age), weighing 2.0–3.5 kg. MethodsRabbits were anesthetized by intramuscular injection of acepromazine (1 mg kg−1), ketamine (30 mg kg−1) and xylazine (3 mg kg−1). Ultrasound-assisted periconal block with lidocaine was performed on 18 eyes. Intraocular pressure was measured by applanation tonometry whereas corneal sensitivity was assessed using an esthesiometer, before and after each periconal anesthesia. ResultsIn all 18 eyes, it was possible to adequately visualize the needle shaft within the periconal space, as well as muscular cone, optic nerve and local anesthetic solution spread. Lidocaine 2% without epinephrine (0.79 ± 0.19 mL) was injected into the periconal space. There was no statistical difference between the intraocular pressure (mean ± SD) measured before (10.9 ± 2.9 mmHg) and after (11.9 ± 3.8 mmHg) the periconal anesthesia (p = 0.38). The effectiveness of the ultrasound-assisted technique was shown according to the values for corneal sensitivity, assessed before and after periconal anesthesia (p < 0.0001). Complications were not observed in this study. ConclusionsEye ultrasonography allowed visualization of all anatomic structures necessary to perform a periconal block, as well as the needle insertion and anesthetic spread in real time. Further studies are required to prove the real potential of ultrasound for reducing the incidence of complications associated with ophthalmic blocks, especially when anatomic disorders of the eye could potentially increase the risk. Clinical relevanceUltrasonography is a painless, noninvasive tool that may improve safety of ophthalmic regional blocks, potentially by reducing the prevalence of globe perforation or penetration of the optic nerve associated with the needle-based techniques.

Complete sacral agenesis: successful spinal anaesthesia for Caesarean section

SummaryWe discuss the case of a female with complete sacral agenesis scheduled for an elective caesarean section. Patients with this condition present a challenge to the anaesthetist, and usually receive a general anaesthetic, due to concerns regarding the precise underlying anatomy and the unpredictability of local anaesthetic spread. We believe that this is the only reported case of a patient with complete sacral agenesis undergoing spinal anaesthesia for an elective caesarean section.

Eficacitatea şi siguranţa blocului de plex brahial ghidat ecografic în chirurgia membrului superior

Introduction. The use of ultrasound (US) for brachial plexus block has increased enthusiasm because the anesthesiologist can visualize anatomy, needle placement, and local anesthetic spread during locoregional anesthesia. The objectives of this prospective study was to evaluate the efficacy and the safety of ultrasound guided brachial plexus block comparative with traditional method of neurostimulation. Material and methods. In this randomized controlled clinical trial we included patients over 18 years old with upper limb surgery and who benefit of brachial plexus block (axillary, interscalenic or combined blocks). After monitoring and sedation, the patients randomly received ultrasound-guided (62 pts.) or neuro stimulation (63 pts.) brachial plexus block with ropivacaine 0.5%. We recorded data about: block success rate, sensitive and motor block onset time, block performance time, immediate and late complications events, patient’s satisfaction rate. The results were statistically analyzed, with significance assumed at p&lt;0.05. Results. Block success rate with ultrasound guidance was very high (93.5% in US group and 84% in NS group). The patients of US group received less volume of local anesthetic (20.89 ± 3.9 ml vs. 43 ± 5.1 ml in NS group, p &lt; 0.05). The performance time, needle punctures, sensory and motor onset time was significant reduced in US group. In the NS group we recorded 2 local anesthetic systemic toxicity (minor-moderate neurologic symptoms) with complete recovery and none in US group. We recorded less paresthesia during block performance and vascular puncture due to US guidance (p&lt;0.05). Patient acceptance with locoregional anesthesia is good, even patients experience more discomfort during neurostimulation technique. Conclusions. The results of this study suggest that both techniques of execution of brachial plexus block are adequate for upper limb surgery but US guidance provides significant benefits for patients in terms of efficacy and safety.

Anestezia locoregională ghidată ecografic în chirurgia membrului superior

Brachial plexus blockade is a cornerstone of the peripheral nerve regional anesthesia practice of most anesthesiologists. The new inovative application of ultrasound imaging may overcome the shortcomings of current techniques and increase the efficacity and safety of locoregional anesthesia. Ultrasound guidence allows the operator to see neural structures, guide the needle under real-time visualization, navigate away from sensitive anatomy, and monitor the spread of local anesthetic. This review article focuses on approaches and techniques used for ultrasound guidance of brachial plexus blocks for upper extremity surgery.

Syndrome de Horner transitoire après anesthésie péridurale thoracique pour mastectomie: étude observationnelle prospective

Transient Horner's syndrome is an uncommon complication of epidural anesthesia, though its exact incidence in thoracic epidural anesthesia is not clear. Therefore, this study prospectively evaluated the incidence of Horner's syndrome after thoracic epidural anesthesia for mastectomy. Patients scheduled for mastectomy, with or without breast reconstruction, were enrolled in this prospective observational study from September 2010 to December 2013. Intraoperative thoracic epidural anesthesia was established using 0.375% or 0.5% ropivacaine 15 mL with thoracic epidural analgesia continued postoperatively with a continuous infusion of 0.15% ropivacaine 2mL·hr(-1) with fentanyl 8μg·hr(-1). Signs of Horner's syndrome (miosis, ptosis, and hyperemia) were assessed at one and two hours as well as one, two, and three days postoperatively. Thoracic epidural anesthesia was successful in 439 patients, with six (1.4%) of these patients acquiring Horner's syndrome. All signs of Horner's syndrome resolved gradually within 180 min of discontinuing the epidural infusion. In one patient with Horner's syndrome, a radiographic contrast injection confirmed that the drug had spread to the cervical epidural level. The incidence of Horner's syndrome following thoracic epidural anesthesia and continuous thoracic epidural analgesia for mastectomy was 1.4%. The mechanism was consistent with cephalic spread of the epidural local anesthetic. This trial was registered at: Clinicaltrials.gov, number: NCT02130739.

Spread patterns and effectiveness for surgery after ultrasound-guided rectus sheath block in adult day-case patients scheduled for umbilical hernia repair.

Background and Aims:We conducted a prospective study to examine the local anesthetic (LA) spread and the effectiveness for surgical anesthesia of ultrasound (US)-guided rectus sheath block (RSB) in adult patients undergoing umbilical hernia repair.Material and Methods:Thirty patients received at T-10 level a bilateral US-guided injection of 20 mL levobupivacaine 0.375% + epinephrine 5 μg/mL behind the rectus muscle to detach it from its sheath. Anesthetic spread into the rectus sheath was evaluated ultrasonographically at T-9 and T-11 levels and scored from 0 to 4. The RSB was defined effective for surgical anesthesia if it was able to guarantee an anesthetic level sufficient for surgery without any mepivacaine supplementation.Results:Overall, the block was effective for surgical anesthesia in 53.3% of patients (95% confidence interval, ±17.8). In the remaining patients, anesthesia supplementation was needed at cutaneous incision, whereas manipulation of the muscle and fascial planes was painless. No patients required general anesthesia. LA spreads as advocated (to T-9 and to T-11 bilaterally = spread score 4) in 8/30 patients (26.6%); in these cases, the block was 75% effective for surgery. The anesthetic spread was most negatively influenced by increased body mass index. Postoperative analgesia was excellent in 97% of patients.Conclusion:Use of RSB as an anesthetic management of umbilical herniorrhaphy is recommended only with anesthetic supplementation at the incision site.

One Shot Six Centres: A New Strategy in Ultrasound Guided Paravertebral Block

The paravertebral block (PVB) is the technique of injecting local anaesthetic alongside the vertebral body close to where the spinal nerves emerge from the intervertebral foramen. This produces unilateral, segmental, somatic, and sympathetic nerve blockade in multiple contiguous thoracic dermatomes which is effective for managing acute and chronic pain. Recently PVB has also been used for surgical anaesthesia in patients undergoing several surgical procedures with improved postoperative outcomes. Unfortunately the spread of local anaesthetic and the anaesthetic effect is sometime unpredictable, even with a standardized ultrasound-guided technique. The aim of this study is to show a new approach for the Paravertebral block ultrasound-guided and confirmed by ENS using a single injection. This new approach allows an easy visualization and accurate puncture of the paravertebral space, ensuring good anaesthesia of reproducibility, productivity and effectiveness. In this study we obtained six dermatomes anaesthesia, with a single shot injection in all patients.

A rare case of postpoliomyelitis quadriparetic patient with severe kyphoscoliosis.

A rare case of postpoliomyelitis quadriparetic patient with severe kyphoscoliosis.

A Combined Spinal Epidural Anesthetic (CSE) for Cesarean Section in a Patient with Achondroplasia. Can MRI be Helpful?

The anatomic features of achondroplastic patients pose many challenges for anesthesiologists. The achondroplastic parturient has a high likelihood of delivery by cesarean section due to cephalopelvic disproportion. Hence, anesthesiologist involvement is crucial. It is not uncommon for these patients to have a narrow spinal canal and areas of spinal stenosis. These features might prove a challenge for a neuraxial technique and potentially result in unpredictable spread of local anesthetic. We present a case in which an abnormal Magnetic Resonance Imaging (MRI) was used to tailor the anesthetic plan for an achondroplastic parturient and possibly explain some of our intraoperative observations.

Pneumoperitoneum Does Not Influence Spread of Local Anesthetics in Midaxillary Approach Transversus Abdominis Plane Block: A Descriptive Cadaver Study.

The transversus abdominis plane (TAP) block can be used as part of a multimodal analgesia protocol after abdominal surgery. This study investigated whether a pneumoperitoneum during abdominal surgery influences the spread of local anesthetics. Nine fresh frozen cadavers were used for the study. Using an ultrasound-guided midaxillary technique, a unilateral TAP block-like injection with 20 mL of methylene blue dye was performed. After the injection, a pneumoperitoneum was immediately installed for 1 hour. After desufflation, this ipsilateral side was dissected, and a TAP block-like injection was performed on the contralateral side. One hour after injection, the contralateral side was also dissected. The anatomical dissection was used to determine the extent of dye spread and the nerves stained by the dye. In none of the specimens did the dye reach the posterior origin of the transverse abdominal muscle. There was no statistically significant difference in the number of stained nerves and spread of the dye in the insufflated side compared with the noninsufflated side. In 4 of 9 cadavers, we found a variant course of a nerve preventing staining of that nerve. The stretch of the abdominal wall caused by the insufflation of the abdomen does not influence the spread of dye in the abdominal wall. Because of the absence of posterior spread, regardless of the timing of a midaxillary ultrasound-guided approach, we believe that a posterior approach should be chosen if posterior spread is desired.

A simple test of baricity for subarachnoid drugs.

A simple test of baricity for subarachnoid drugs.

The effect of the Oxford Head Elevating Laryngscop Pillow (O/HELP) on subarachnoid local anaesthetic spread in elective Caesarean section: a randomized controlled trial

The effect of the Oxford Head Elevating Laryngscop Pillow (O/HELP) on subarachnoid local anaesthetic spread in elective Caesarean section: a randomized controlled trial