Anesthetic Spread Research Articles

Challenges, solutions, and advances in ultrasound-guided regional anaesthesia

### Key points Ultrasonography offers significant advantages in the practice of regional anaesthesia, including faster sensory onset and improved success rates compared with landmark-based techniques.1 Adequate visualization of neural and surrounding structures together with monitoring the spread of local anaesthetic (LA) are absolute prerequisites for the safe and successful practice of ultrasound-guided regional anaesthesia (USGRA). The creation of an ultrasound (US) image is based on the physical properties of the US beam formation, propagation of sound in matter, interaction of sound with reflective interfaces, echo detection, and machine processing. However, there are often a number of significant challenges to acquiring the optimal US images necessary to achieve successful nerve blocks. Such challenges include the acquisition and interpretation of optimal US images of the target structure and needle while avoiding tissue and needle artifacts. Other difficulties may include physiological, pathological, and anatomical factors attributable to the patient and which may affect image quality and interpretation. This article will describe some of these problems, discuss strategies to avoid them, and highlight current and future advances which may assist the practice of USGRA. The spatial resolution of any imaging system is defined as its ability to distinguish two points as separate entities in space. Spatial resolution is commonly subcategorized into axial and lateral resolution.2 Axial resolution is defined as the US machine's ability to differentiate two objects located at different …

Introduction of a novel ultrasound-guided extrathoracic sub-paraspinal block for control of perioperative pain in Nuss procedure patients

BackgroundA safe and effective method of multilevel thoracic pain control remains an elusive goal in patients undergoing the Nuss procedure. The aim of our study was to develop a nonopioid centered approach using a novel regional technique as part of a quality improvement initiative. MethodsThe proposed ultrasound-guided technique positions multi-perforated soaker catheter deep to the paraspinal muscles from T2 to T11. The project was conducted in two phases. First, a cadaveric dissection was performed to establish the pathway of spread of local anesthetic in vivo. Second, a pilot double blind randomized control project was conducted to evaluate effectiveness of the technique in ten patients and to derive parameters necessary for the definitive future study. Outcomes were evaluated based on the narcotic requirement, pain scores and functional measures. ResultsPlacement of the catheters in two cadavers demonstrated reliable positioning in the subparaspinal tissue plane, and multilevel dye spread along the intercostal nerve path. In addition, a potential route of spread toward the paravertebral space along the canal accommodating dorsal ramus of the thoracic nerve was demonstrated. The pilot trial demonstrated a trend in decreased cumulative hydromorphone requirement in comparison to the control group at both 24h (0.19±0.09mg/kg vs. 0.13±0.08mg/kg p=0.72) and 48h (0.37±0.2mg/kg vs. 0.3±0.12mg/kg p=0.37). Functional performance ability was higher in the treatment group on both POD#1 (6.7±1.8 vs. 4.8±1 p=0.0495) and POD#2 (8.9±0.8 vs. 6.5±1.2 p=0.04). Pain scores were similar among the two groups (p=0.96). ConclusionsWe describe a new technique to treat multilevel thoracic pain following the Nuss procedure that is reproducible, safe, allows diminished opioid use and enhances functional recovery.

Abstract PR515

Background & Objectives: Paravertebral block has become a popular technique and is considered as effective as epidural block for pain control. Local anesthetic (LA) spread pattern within the thoracic paravertebral space (PVS) could be highly variable. Injection of LA into the posterior compartment or the anterior compartment of the PVS results in a cloud-like spread or a longitudinal multisegmental spread image, respectively1). However, There are no reports to examine the relationship between the pattern of the local anesthetics spread and analgesic effects after the same operation. We investigated the spread pattern of contrast dye through the catheter into the PVS in patients undergoing breast cancer operation and whether the spread pattern could be related with analgesic effects for acute post operative pain. Materials & Methods: Between June 2014 and January 2016, we designed a prospective study of 60 patients submitted to unilateral breast cancer surgery without reconstruction. After the operation, the catheter was placed into the PVS using the ultrasound-guided out-of-plane needle insertion approach at the forth thoracic vertebral level under general anesthesia. When we could confirm an anterior movement of the pleura by injection of 25mL of 0.33% ropivacaine, the catheter was judged to be in the PVS. A 5ml of radiographic contrast dye was injected through the catheter and the spread pattern was assessed by X-ray images. Patients recieved continuous 0.2% ropivacaine infusion at the rate of 3ml/h. A numeric rating scale (NRS) was used to assess pain intensity at rest and on moving at 1, 6 and 12 h after operation. Analgesic consumption was also noted. Results: The catheters were judged to be in the PVS in 43 among 60 patients. Fifteen patients showed multisegmental longitudinal spread pattern and 7 patients showed cloud-like spread pattern. Their median NRS (Interquartile range) at 1 h after operation were 3 (0.5-5.5) in multisegmental longitudinal pattern group and 4 (1.5-8) in cloud-like pattern group. Patients who required rescue analgesics within 1 h after operation were 66.7% or 42.9% in multisegmental longitudinal pattern group or in cloud-like pattern group, respectively. Conclusion: Multisegmental longitudinal pattern and cloud-like pattern of paravertebral block had the same analgesic effect after breast cancer operation. Therefore, pattern of contrast dye through the thoracic paravertebral catheter dose not predict analgesic efficacy.

The effect of parturient height on the median effective dose of intrathecally administered ropivacaine.

BACKGROUNDPain during cesarean delivery is one of the more common reasons for a successful medico-legal claim. However, creating an extensive block area can result in hypotension, so determining the precise dose of local anesthetic is critical.OBJECTIVESInvestigate effects of parturient height on the median effective dose (ED50) of intrathecally-administered ropivacaine.DESIGNProspective cross-sectional analytic study.SETTINGAnesthesiology department in a provinicial hospital in China.METHODSParturients undergoing cesarean delivery under combined spinal and epidural anesthesia were stratified according to height as follows: 150 cm to 155 cm, 156 cm to 160 cm, 161 cm to 165 cm and 166 cm to 170 cm. The spinal component of the anesthetic was established by bolus administration of up-and-down doses of 0.75% plain ropivacaine as determined by the Dixon method. The initial dose of ropivacaine was 5.79 mg and the testing interval dose change was set at 0.75 mg. The block height for the first cold feeling at T5 was considered satisfactory anesthesia.MAIN OUTCOME MEASURESED50 values and vasopressor requirements, nausea, vomiting and shivering.RESULTSIn 120 parturients, the ED50 for satisfactory block height using intrathecal ropivacaine was 5.92 mg (95% confidence interval[CI] 5.02–6.86 mg) patients of 150 to 155 cm in height; 6.52 mg (95% CI 5.45–7.65 mg) in 156 cm to 160 cm; 7.49 mg (95%CI 6.83–8.25 mg) in 161 cm to 165 cm; 8.35 mg ( 95%CI 7.55–9.23 mg) in 166 to 170 cm. The ED50 of ropivacaine increased with increasing height of the subject. There were no significant differences in incidence of hypotension, vasopressor requirements, nausea, vomiting and shivering.CONCLUSIONThe ED50 of intrathecal ropivacaine using sensitivity to cold sensation increased with parturient height, indicating that dose may be determined in part by height.LIMITATIONThe ED95 rather than the ED50 for spinal anesthesia is more useful clinically. We did not control for the effect of weight on the dose of local anesthetic. Factors such as baricity, volume, concentration injected, temperature of the solution, and viscosity can affect intrathecal spread of the local anesthetics and block quality.

Prospective Randomised Study To Compare Inj Dexmedetomidine And Inj Clonidine As Adjuvant To Bupivacaine Used For Ultrasound Guided Subclavian Perivascular And Axillary Block In Upper Limb Surgeries

Background: Ultrasound continues to grow in popularity as a method of nerve localization and it has the advantage of allowing real time visualization of the plexus , pleura and vessels along with the needle and local anaesthetic spread. [4] So this study intends to compare efficacy and safety of Inj.clonidine and Inj.Dexmedetomidine as adjuvant to local anaesthetic for USG guided subclavian perivascular and axillary block in upper limb surgeries. Materials and Methods: We conducted this study as a prospective randomized study. A total of 70 adult patients were randomly selected who fulfilled the inclusion criteria. They were divided into groups and study was conducted. Results: In this study, we measured the results of each drug by its action on onset and peak of sensory and motor blockade and duration of blockade. Conclusion: From our study we conclude that both Clonidine and Dexmeditomidine with local anaesthetics promote satisfactory anaesthesia for upper limb surgeries. Onset and duration sensory blockade of clonidine group is faster and duration of sensory blockade is more than dexmeditomidine group as adjuvant to local anaesthetics in USG guided subclavian pervascular block plus axillary block.

Abstract PR292

Background & Objectives: Pediatric supracondylar fractures of the humerus are managed by closed reduction with percutaneous pinning (CRPP) under general anesthesia. Opioids are given for analgesia, but associated side effects are concerns. Ultrasound visualization of local anesthetic spread has increased success rates in pediatric regional anesthesia. There are no prospective comparisons of the two analgesic techniques. This IRB approved prospective, patient and observer blinded, randomized controlled trial compared outcomes in children with fractures undergoing CRPP, who received an intraoperative supraclavicular block with ultrasound (UGRA) or intravenous opioids during general anesthetia. Materials & Methods: 115 ASA I or II children were enrolled excluding those with compromised neurovascular status, obstructive sleep apnea or anesthetic allergies. Randomized 1:1 to UGRA or IV Opioids Pain scores, opioid consumption and side effects were recorded during hospital stay and parents asked to complete a postdischarge diary. Primary outcome was peak pain scores over 48 hours. Secondary outcomes included 48 hour opioid consumption in morphine equivalents, time to first analgesia request, incidence of nausea and vomiting, itching, respiratory depression, time in PACU. Results: Data from 4 subjects excluded for change in operative procedure and protocol violations During the intraoperative period the UGRA group had: - Lower intraoperative opioid requirements - Higher oxygen saturation values - Longer OR times (median difference 5 minutes) - No difference in surgical times or time from end of surgery to PACU arrival - No difference in time from end of surgery to eye opening / response to command / first oral intake During the PACU stay, UGRA group had: - Lower pain scores and opioid consumption - Lower peak emergence delirium scores on the PAED scale - Fewer patients requiring opioid rescue - Longer time to first opioid rescue - Shorter time to discharge readiness in the PACU stay (median difference 12 minutes) - 64 parents returned diaries with recorded pain scores at 12, 24 and 48 hours - During the 48 hour postoperative period the UGRA group had: - Lower peak and mean pain scores on the FLACC and verbal pain scales - Lower opioid consumption in morphine equivalent mg /kg - Higher pain scores by child and parent at the 12 hour point but no difference at other times Conclusion: - UGRA provides superior analgesia for CRPP when compared to IV opioids - Parents and children should be warned to expect pain when the block wears off and to provide rescue analgesia early.

Observation of ultrasound-guided thoracic paravertebral block using thoracoscopy

We previously reported an approach to ultrasound-guided thoracic paravertebral block (USG-TPVB) that used a transverse image of the thoracic paravertebral space (TPVS) and in-plane needling.1 In this technique, we aimed to position a needle tip into the lateral edge of the TPVS between the internal intercostal membrane and the parietal pleura. Successful injection is confirmed by observing the parietal pleura being pressed down ventrally by a local anesthetic. However, the steric spread of the local anesthetic in the TPVS has been unclear.

Axillary local anesthetic spread after the thoracic interfacial ultrasound block – a cadaveric and radiological evaluation

BackgroundOral opioid analgesics have been used for management of peri- and postoperative analgesia in patients undergoing axillary dissection. The axillary region is a difficult zone to block and does not have a specific regional anesthesia technique published that offers its adequate blockade. MethodsAfter institutional review board approval, anatomic and radiological studies were conducted to determine the deposition and spread of methylene blue and local anesthetic injected respectively into the axilla via the thoracic inter-fascial plane. Magnetic Resonance Imaging studies were then conducted in 15 of 34 patients scheduled for unilateral breast surgery that entailed any of the following: axillary clearance, sentinel node biopsy, axillary node biopsy, or supernumerary breasts, to ascertain the deposition and time course of spread of solution within the thoracic interfascial plane in vivo. ResultsRadiological and cadaveric studies showed that the injection of local anesthetic and methylene blue via the thoracic inter-fascial plane, using ultrasound guide technique, results in reliable deposition into the axilla. In patients, the injection of the local anesthetic produced a reliable axillary sensory block. This finding was supported by Magnetic Resonance Imaging studies that showed hyper-intense signals in the axillary region. ConclusionsThese findings define the anatomic characteristics of the thoracic interfascial plane nerve block in the axillary region, and underline the clinical potential of this novel nerve block.

Levobupivacaine for Spinal Anesthesia in Children: Cerebrospinal Fluid Aspiration Before the Injection Does not Affect the Spread or Duration of the Sensory Block.

BackgroundSeveral factors are thought to affect the spread and duration of spinal anesthesia (SA) in adults. These include the volume of cerebrospinal fluid (CSF) in the lumbar spinal canal, which has a negative correlation with both the spread and duration of the sensory block.ObjectivesWe evaluated whether CSF aspiration before an injection of levobupivacaine affected the spread or duration of SA in children.Patients and MethodsSA was induced by levobupivacaine (5 mg/mL, 0.25 - 0.5 mg/kg) in 186 children aged 10 months to 18 years (mean of 7.5 years). Two groups were analyzed prospectively: 93 children from which 1 - 3 mL of CSF (CSF-aspiration group) was aspirated before the injection of levobupivacaine to induce SA and 93 children from which no CSF was aspirated (no-CSF-aspiration group) prior to the injection of levobupivacaine. The main outcome measure was regression of the sensory block below T10, cephalic spread of the block, and postpuncture complications after SA.ResultsThere were no between-group differences in the time to regression of the block below T10 or in the cephalic spread of the sensory block: 94 (27) minutes and T4.4 (SD 2.2) in the CSF-aspiration group, respectively, vs. 97 (29) minutes and T4.3 (1.8), respectively, in the no-CSF-aspiration group. Position-dependent headaches developed in 4 of 91 children in the CSF-aspiration group and 5 of 86 children in the no-CSF-aspiration group, but no epidural blood patches were required.ConclusionsThe aspiration of 1 - 3 mL of CSF before an injection of levobupivacaine did not seem to affect the spread and duration of the sensory block or postpuncture complications in children following SA.

Utility of transesophageal echocardiography in identifying spinal canal structures and epidural catheter position: a prospective observational study of intraoperative hemodynamics and postoperative analgesia.

The aims of this study were to determine the utility of transesophageal echocardiography (TEE) for identifying spinal canal structures and epidural catheter position and to assess the effect of catheter position on intraoperative hemodynamics and quality of postoperative analgesia. Twenty-six adult patients undergoing thoracic surgery were included in this prospective, observational study. An epidural catheter was inserted 7.5 cm or more into the thoracic epidural space using a midline approach and a loss-of-resistance technique. A pediatric TEE probe was inserted after induction of general anesthesia. It was used to identify the spinal canal structures, the catheter tip position in the epidural space, and the spread of injected local anesthetic. Intraoperative hemodynamics, postoperative visual analogue scale (VAS) pain scores, and the need for rescue epidural doses were recorded and compared between groups determined by their catheter position. Two subjects were excluded from the study because of an intrathecally positioned epidural catheter. The remaining 24 subjects were divided into two groups based on TEE-determined epidural catheter position: posterior (Gr-P) or lateral (Gr-L). Spinal canal structures and the epidural catheter was successfully identified in all patients. The epidural catheter was located posteriorly in 20 (83%) patients and laterally in four (17%) patients. The spread of the local anesthetic was bilateral in all Gr-P patients, whereas it was unilateral in all but one of the Gr-L patients. Compared to Gr-P patients, Gr-L patients had higher heart rates and blood pressures at various time points after local anesthetic administration until the end of surgery (P = 0.02 to < 0.001). Postoperative VAS scores (P = 0.02) and the median number of rescue analgesic doses required during the intraoperative and postoperative periods were also higher in Gr-L patients (P < 0.001). Transesophageal echocardiography reliably identified spinal canal structures and the position of epidural catheters in the epidural space in adult patients. Posteriorly located epidural catheters appear to provide better epidural analgesia than laterally situated catheters.

Accidental Bilateral Sciatic Nerve Block After Gynecologic Procedure

Abstract Background: Local anesthesia techniques for minor obstetric and gynecologic procedures are routinely performed around the world, as these techniques are relatively easy to learn and perform. The low complication rate of these techniques is commendable, given the busy clinical environment in which obstetricians and gynecologists practice. However, complications do occur. Case: A 48-year-old female was scheduled for ambulatory surgery for a rectocele with cervical amputation under general anesthesia. Perioperatively, the surgeon performed pudendal and paracervical blockades along with local anesthetic infiltration of the sacrouterine ligaments. In the postoperative period, the patient presented with bilateral sciatic nerve blockage, which was caused by an unintended spread of the local anesthetic. She was admitted for further observation. Results: This patient's sensory and motor deficit was resolved spontaneously by the next morning. Conclusions: Awareness regarding possible complications, prevent...

Horner syndrome after epidural analgesia for labor. Report on three cases

Epidural analgesia is assumed to be the technique of choice for the relief of pain in labor. Multiple adverse neurological effects have been reported, one of which is the so-called Horner syndrome (ptosis, myosis, anhidrosis). Its evolution is usually benign and does not require specific management, except clinical monitoring for the more than probable cephalic spread of local anesthetic. Most of the cases that exist in the literature are isolated; in our work we present a series of 3 clinical cases and review the pathogenesis and management in the obstetric patient.

The Effect of Intra-Abdominal Pressure on Sensory Block Level of Single-Shot Spinal Anesthesia for Cesarean Section

(Int J Obstet Anesth. 2015;24(1):35–40) There is an association between pregnancy and increased intrathecal local anesthetic spread (and thus, lower local anesthetic requirements), although the exact mechanisms behind this association are unknown. There are 2 potential anatomic explanations: (1) in the supine position, the pregnant uterus compresses the inferior vena cava (IVC), diverting blood into the vertebral venous system and displacing lumbosacral cerebrospinal fluid (CSF) in a cranial direction; or (2) in addition to direct compression of the IVC, the growing uterus during pregnancy leads to a global increase in intra-abdominal pressure (IAP).

Easier and Safer Regional Anesthesia and Peripheral Nerve Block under Ultrasound Guidance.

Regional anesthesia for the peripheral nerve or plexus has been widely used in the management of acute or chronic pain. To deliver a smaller volume to the targeted nerve without injury to it or its surrounding structures can be critical in the practice of regional anesthesia [1]. Therefore, the identification of the target nerve is important to provide better efficacy and safety in regional anesthesia. To increase the success rate of target nerve blocks, an electrical nerve stimulation device is popularly used. However, in spite of the use of a nerve stimulator, it is sometimes difficult to identify the exact position of the tip of the needle [2]. Since 1978, ultrasound has been widely used in several kinds of regional anesthetic practices. Recently, the improvements in ultrasound technology allow you to place the tip of the needle near the targeted nerve and monitor the spread of the local anesthetics precisely. In addition, ultrasound guidance enables the physician to replace the needle in the case of mal-distribution of the local anesthetic in real time. Therefore, ultrasound-guided technique has been considered the gold standard for performing regional anesthesia or peripheral nerve blocks [3]. The interscalene brachial plexus (IBP) block is very useful for upper extremity surgery. But IBP at the C6 level often fails to affect the ulnar nerve in up to 50% of blocks [4]. Kim et al. [2] injected 55 ml of local anesthetic via low approach IBP below the C6 level using a nerve stimulator for upper extremity surgery. A low approach IBP provided more caudad spread of local anesthesia in the brachial plexus, resulting in a better efficacy in blocking the ulnar nerve than the conventional IBP approach at the C 6 level (46% vs 81%; P < 0.0001). However, it may be associated with several concerns. The vertebral artery enters deep into the transverse process at the level of C6 or C7. Therefore, a nerve stimulant guided low approach IBP below the C6 level increases the risk of vertebral artery puncture, which may result in catastrophic outcomes. The nerves from C5 and C6 innervate the upper arm or forearm. When muscular twitching in the forearm is observed, it is difficult to identify whether the motor response originates from the C5 or C6 nerve. And thus, it is difficult to identify the exact position of the tip of the needle from the nerve stimulation. In this issue, Park et al. [5] reported the effect of ultrasound guided low approach IBP for upper limb surgery. They used 40 ml of local anesthetics for IBP, which provided adequate anesthesia without any significant complications in all 20 patients. Ultrasound provides direct visualization of the best site for the injection and helps avoid incidental puncture of blood vessels and damage to nerves. In addition, the volume of local anesthetic needed can be reduced by monitoring the spread of local anesthetics. Thus, continuously observing the distribution of local anesthetic and replacing the needle when mal-distribution of the injectate occurs improves the efficacy and safety of regional anesthesia or peripheral nerve block under ultrasound guidance. Substantially, the use of ultrasound can decrease the performance time of regional anesthesia, which may promote the routine use of ultrasound guidance in regional anesthesia. Therefore, it is justified to enable physicians to acquire the knowledge and techniques to use ultrasound guidance in regional anesthesia and in performing peripheral nerve blocks.

Monitored anesthesia care with propofol or dexmedetomidine for patients undergoing upper limb surgeries under brachial plexus blockade: a comparative study

Background Brachial plexus block is widely used for upper limb surgeries but intraoperatively patients remain aware. The present study aimed to compare the sedative efficacy and safety of propofol infusion versus dexmedetomidine infusion for monitored anesthesia care during upper limb surgeries under ultrasound (US)-guided brachial plexus blockade. Patients and methods Sixty adult consented patients of American Society of Anesthesiologists physical status I–III of both sexes were given 20 ml of 0.75% ropivacaine (150 mg) for brachial plexus blockade under US guidance. The patients were randomized into two groups of 30 patients each, to receive either propofol infusion [group I (P)] or dexmedetomidine infusion [group II (D)] during the intraoperative period. The primary goals were to achieve a sedation score of 2–3 on the Ramsay sedation scale and to compare the duration of postoperative analgesia assessed using the visual analog scale. The hemodynamic stability, respiratory depression, or any complication due to technique or medications was also recorded as secondary outcomes. Results US guidance helped visualization of the nerves, the needle, and the spread of local anesthetic at the brachial plexus block site. Desired sedation score of 2–3 was effectively achieved with intraoperative infusions of dexmedetomidine and propofol. Hypotension occurred in 11 patients of the propofol group, whereas no episode of hypotension was noted in the dexmedetomidine group. Bradycardia was evident in five patients of the dexmedetomidine group. The duration of postoperative analgesia with dexmedetomidine infusion was significantly prolonged when compared with propofol infusion as assessed using visual analog scale. Respiratory depression did not occur in any patient. No adverse events inherent to sedative medication or technique were observed in any patient. Conclusion The clinical efficacy and safety of dexmedetomidine was better than propofol due to prolonged postoperative analgesia and intraoperative hemodynamic stability without respiratory depression.

Nalbuphine as an adjuvant to 0.5% bupivacaine for ultrasound-guided supraclavicular brachial plexus blockade

Background: Brachial plexus block is a reliable, regional anesthetic technique for upper arm surgeries. Opioid agonist-antagonists are also used as adjuvant to enhance the analgesia of bupivacaine. The present study was aimed to assess the analgesic efficacy and safety of nalbuphine as an adjuvant to 0.5% bupivacaine for brachial plexus block. Patients and Methods: Sixty adult patients of American Society of Anesthesiologists physical status I and II of both genders were randomized into two groups of thirty patients each to receive either 20 mL of 0.5% bupivacaine with 1 mL of normal saline (Group 1) or 20 mL of 0.5% bupivacaine with 1 mL of nalbuphine 10 mg (Group 2) for brachial plexus block under ultrasound guidance. Patients were observed for onset and duration of sensory and motor block with duration of pain relief as primary end points while occurrence of any adverse effect due to technique or nalbuphine was noted as secondary outcome. Results: The ultrasound guided the visualization of the nerves, needle, and spread of local anesthetic at brachial plexus block site. Nalbuphine did not affect the onset time of block but enhanced the duration of sensory and motor block. The duration of postoperative analgesia was 481.53 ± 42.45 min in Group 2 and 341.31 ± 21.42 min in Group 1, with statistically highly significant difference (P < 0.001). There were no hemodynamic variations and no complication of technique or adverse effects due to nalbuphine occurred. Conclusion: Nalbuphine 10 mg has significantly extended the duration of analgesia of brachial plexus block with no adverse effects.

Subarachnoid block in kyphoscoliosis: A reliable technique?

Subarachnoid block in patients with kyphoscoliosis always present a unique challenge to the anesthesiologist owing to the deformity of spine. The asymmetry in bilateral spread of local anesthetic has been reported earlier. We present a case report of poliomyelitis patient with fracture femur (left) with thoracolumbar kyphoscoliosis posted for open reduction internal fixation. Anesthesia planned in this patient was subarachnoid block with modified paramedian approach which resulted in unilateral sensory block.

The Infiniti Plus ultrasound needle guidance system improves needle visualization during the placement of spinal anesthesia.

The Infiniti Plus ultrasound needle guidance system improves needle visualization during the placement of spinal anesthesia.

Evidence for the Use of Ultrasound Imaging in Pediatric Regional Anesthesia: A Systematic Review.

Studies in the current review provide stronger evidence and have addressed a number of outcomes that were previously inconsistent or lacked strength in evidence. In the current systematic review, we identified more studies in a shorter period compared with the previous review, and these studies contain higher levels of evidence compared with what we previously found. Randomized controlled trials and well-designed prospective observational studies have replaced case series. Stronger evidence from the literature suggests that ultrasound-guided peripheral blocks decrease block performance time when compared with nerve stimulation (but take longer than the landmark technique), increase block success, and increase block quality (as measured by analgesic consumption, block duration, and pain scores). Ultrasound guidance in neuraxial blocks improves needling time, predicts epidural depth, allows visualization of the catheter and local anesthetic spread, and improves block quality. Furthermore, we identified 2 large-scale prospective studies describing the incidence of adverse events and complications in pediatric regional anesthesia. The increase in evidence presented in this review reflects the efficacy and prevalent use of ultrasound imaging in pediatric regional anesthesia.

Phrenic nerve block caused by interscalene brachial plexus block: breathing effects of different sites of injection

BackgroundInterscalene brachial plexus (ISB) block is often associated with phrenic nerve block and diaphragmatic paresis. The goal of our study was to test if the anterior or the posterior ultrasound guided approach of the ISB is associated with a lower incidence of phrenic nerve blocks and impaired lung function.MethodsThis was a prospective, randomized and single-blinded study of 84 patients scheduled for elective shoulder surgery who fullfilled the inclusion and exclusion critereria. Patients were randomized in two groups to receive either the anterior (n = 42) or the posterior (n = 42) approach for ISB. Clinical data were recorded. In both groups patients received ISB with a total injection volume of 15 ml of ropivacaine 1 %. Spirometry was conducted at baseline (T0) and 30 min (T30) after accomplishing the block.Changes in spirometrical variables between T0 and T30 were investigated by Wilcoxon signed-rank test for each puncture approach. The temporal difference between the posterior and the anterior puncture approach groups were again analyzed by the Wilcoxon-Mann-Whitney test.ResultsThe spirometric results showed a significant decrease in vital capacity, forced expiratory volume per second, and maximum nasal inspiratory breathing after the Interscalene brachial plexus block; indicating a phrenic nerve block (p <0.001, Wilcoxon signed-rank). A significant difference in the development of the spirometric parameters between the anterior and the posterior group could not be identified (Wilcoxon-Mann-Whitney test). Despite the changes in spirometry, no cases of dyspnea were reported.ConclusionA different site of injection (anterior or posterior) did not show an effect in reducing the cervical block spread of the local anesthetic and the incidence of phrenic nerve blocks during during ultrasound guided Interscalene brachial plexus block. Clinical breathing effects of phrenic nerve blocks are, however, usually well compensated, and subjective dyspnea did not occur in our patients.Trial registrationGerman Clinical Trials Register (DRKS number 00009908, registered 26 January 2016).