Ultrasound-guided selective trunk block: Evaluation of ipsilateral sensorimotor block dynamics, hemidiaphragmatic function and efficacy for upper extremity surgery. A single-centre cohort study.

BACKGROUND: Selectively locating and blocking the individual trunks of the brachial plexus with small volumes of local anaesthetic, a selective trunk block (SeTB), may produce anaesthesia of the entire upper extremity except for the T2 dermatome. OBJECTIVE: This study aimed to evaluate the effects of an ultrasound-guided (USG) SeTB on ipsilateral sensorimotor block dynamics, hemidiaphragmatic function, and efficacy as an all-purpose regional anaesthetic technique for upper extremity surgery. DESIGN: Prospective cohort study. SETTING: Single-centre, university hospital in Hong Kong, China from February 2021 to July 2021. PATIENTS: Thirty patients (aged 53.2 ±â€Š14.8 years and BMI 23.8 ±â€Š3.6 kg m - 2 ), ASA physical status I to III, scheduled for upper extremity surgery under a brachial plexus block. INTERVENTIONS: USG SeTB with 25 ml (7, 8 and 10 ml to the superior, middle and inferior trunks, respectively) of a 1 : 1 mixture of 2% lidocaine with 1 : 200 000 epinephrine and 0.5% levobupivacaine. MAIN OUTCOME MEASURES: Ipsilateral sensorimotor blockade of the suprascapular (only motor), axillary, radial, ulnar, median and musculocutaneous nerves were assessed at regular intervals for 45 min. Ipsilateral hemidiaphragmatic excursion was also measured, at 30 min after the SeTB, using M-mode ultrasound. The SeTB was considered a success if it was possible to complete surgery without any rescue analgesia or conversion to general anaesthesia. RESULTS: Complete motor blockade of the suprascapular nerve was achieved in median [range] 5 [5 to 15] min. Complete sensory and motor blockade were achieved in all the other 5 nerves in 17.5 [10 to 30] and 15 [10 to 30] min respectively. The SeTB was successful in 93% and ipsilateral hemidiaphragmatic paresis (HDP) was present in 82%, of patients. CONCLUSION: SeTB produces sensorimotor blockade of the entire upper extremity, causes ipsilateral HDP, and is effective as the sole anaesthetic for surgery from the proximal humerus to the hand. TRIAL REGISTRION: ClinicalTrials.gov, Trial Registration No: NCT04752410, Date submitted for Registration: 09 February 2021, Date first posted: 12 February 2021, Dates of patient enrolment: 19 February 2021 to 27 July 2021 ( https://clinicaltrials.gov/ct2/show/NCT04752410 ).

Ultrasound-guided selective trunk block (SeTB): a cadaver anatomic study to evaluate the spread of dye after a simulated injection.

BACKGROUND AND OBJECTIVES: Recent reports suggest that a selective trunk block (SeTB) can produce sensorimotor blockade of the entire upper extremity, except for the T2 dermatome. There are no data demonstrating the anatomic mechanism of SeTB. This cadaver study aimed to evaluate the spread of an injectate after a simulated ultrasound-guided (USG) SeTB. METHODS: USG SeTB (n=7) was performed on both sides of the neck in four adult human cadavers with 25 mL of 0.1% methylene blue dye. Anatomic dissection was performed to document staining (deep, faint, and no stain) of the various elements of the brachial plexus from the level of the roots to the cords, including the phrenic, dorsal scapular, and long thoracic nerves. Only structures that were deeply stained were defined as being affected by the SeTB. RESULTS: All the trunks and divisions of the brachial plexus, as well as the ventral rami of C5-C7 and suprascapular nerve, were deeply stained in all (100%) the simulated injections. The ventral rami of C8 and T1 (86%), dorsal scapular and long thoracic nerve (71%), and the phrenic nerve (57%) were also deeply stained in a substantial number of the injections. CONCLUSION: This cadaver study demonstrates that an USG SeTB consistently affects all the trunks and divisions of the brachial plexus, as well as the suprascapular nerve. This study also establishes that SeTB may not be phrenic nerve sparing. Future research to evaluate the safety and efficacy of SeTB as an all-purpose brachial plexus block technique for upper extremity surgery is warranted. TRIAL REGISTRATION NUMBER: Registered at https://www.thaiclinicaltrials.org on December 13, 2021 under the trial registration number TCTR20211213005.

Ultrasound-Guided Multilevel Thoracic Paravertebral Block and Its Efficacy for Surgical Anesthesia During Primary Breast Cancer Surgery.

PURPOSE: Thoracic paravertebral block (TPVB), in conjunction with intravenous sedation, is reported to provide surgical anesthesia for primary breast cancer surgery (PBCS). Although ultrasound-guided (USG) TPVB has been described, there are no reports of USG multilevel TPVB for surgical anesthesia during PBCS. The aim of this prospective observational study was to determine the feasibility of performing USG multilevel TPVB, at the T1-T6 vertebral levels (6m-TPVB), and to evaluate its efficacy in providing surgical anesthesia for PBCS. PATIENTS AND METHODS: Twenty-five female patients undergoing PBCS received an USG 6m-TPVB for surgical anesthesia. Four milliliters of ropivacaine 0.5% (with epinephrine 1:200,000) was injected at each vertebral level. Dexmedetomidine infusion (0.1-0.5 µg.kg-1.h-1) was used for conscious sedation. Success of the block, for surgical anesthesia, was defined as being able to complete the PBCS without having to resort to rescue analgesia or convert to GA. RESULTS: The USG 6m-TPVB was successfully performed on all 25 patients but it was effective as the sole anesthetic in only 20% (5/25) of patients. The remaining 80% (20/25) reported pain during separation of the breast from the pectoralis major muscle and its fascia. Surgery was successfully completed using small doses of intravenous ketamine (mean total dose, 38.0±20.5 mg) as supplementary analgesia. CONCLUSION: USG 6m-TPVB is technically feasible but does not consistently provide complete surgical anesthesia for PBCS that involves surgical dissection on the pectoralis major muscle and its fascia. Our data suggest that the pectoral nerves, which are not affected by a 6m-TPVB, are involved with afferent nociception.

Minimum effective volume of 0.5% ropivacaine for ultrasound-guided costoclavicular brachial plexus block: A dose finding study.

BACKGROUND: Costoclavicular brachial plexus block (CC-BPB) is a relatively new regional anaesthetic technique and there are no data on the minimum effective volume 90 (MEV90) of 0.5% ropivacaine required for an ultrasound-guided CC-BPB. OBJECTIVE: To determine the MEV90 of 0.5% ropivacaine required to produce surgical anaesthesia with an ultrasound-guided CC-BPB. DESIGN: Prospective up-down sequential allocation study design. SETTING: University teaching hospital in Hong Kong from March 2016 to December 2017. PATIENTS: Forty-eight, ASA physical status I to III patients, aged 70 years or less and scheduled for elective forearm or hand surgery under an ultrasound-guided CC-BPB, were recruited. INTERVENTION: Ultrasound-guided CC-BPB was performed with the assigned volume of 0.5% ropivacaine. The Dixon 'up-and-down' sequential allocation method using the biased coin design was used to determine the MEV90 of 0.5% ropivacaine. The assigned volume of ropivacaine was based on the outcome of the previous patient. After a block failure the next patient received a volume increase of 2 ml. If the block was a success, the next patient was allocated, with a probability of b = 0.11, to receive 2 ml less, or, with a probability of 1 - b = 0.89, the same volume. MAIN OUTCOME MEASURES: A successful block was defined as a minimum score of 14 of 16 points, using a composite sensory and motor block score at 45 min after the injection. The study was stopped when 45 successful blocks were achieved. MEV90 with 95% confidence interval was calculated using the centred isotonic regression for point and interval dose response studies. RESULTS: The MEV90 of 0.5% ropivacaine for ultrasound-guided CC-BPB was 20.9 (95% confidence interval, 20.7 to 21.8) ml. The mean ±â€ŠSD time to readiness for surgery was 31.4 ±â€Š12.60 min. CONCLUSION: The MEV90 of 0.5% ropivacaine required to produce surgical anaesthesia with an ultrasound-guided CC-BPB is 20.9 ml. CLINICAL TRIAL REGISTRATION: The trial was registered with the Chinese Clinical Trials Registry (www.chictr.org.cn, ChiCTR-IOR-15007515, principal investigator: Manoj Kumar Karmakar, date of registration: 4 December 2015). CLINICAL TRIAL NUMBER AND REGISTRY URL: ChiCTR-IOR-15007515, Chinese Clinical Trials Registry (www.chictr.org.cn).

High definition ultrasound imaging of the individual elements of the brachial plexus above the clavicle.

BACKGROUND AND OBJECTIVES: Ultrasonography of the brachial plexus (BP) has been described but there are limited data on visualization of the T1 ventral ramus and the inferior trunk. This prospective observational study aimed to evaluate a high definition ultrasound imaging technique to systematically identify the individual elements of the BP above the clavicle. METHODS: Five healthy young volunteers underwent high definition ultrasound imaging of the BP above the clavicle. The ultrasound scan sequence (transverse oblique scan) commenced at the supraclavicular fossa after which the transducer was slowly swept cranially to the upper part of the interscalene groove and then in the reverse direction to the supraclavicular fossa. The unique sonomorphology of the C7 transverse process was used as the key anatomic landmark to identify the individual elements of the BP in the recorded sonograms. RESULTS: The neural elements of the BP that were identified in all volunteers included the ventral rami of C5-T1, the three trunks, divisions of the superior trunk, and formation of the inferior trunk (C8-T1). The C6 ventral ramus exhibited echogenic internal septation with a split (bifid) appearance in four of the five volunteers. In three of the four volunteers with a bifid C6 ventral ramus, the C7 ventral ramus was also bifid. CONCLUSION: We have demonstrated that it is feasible to accurately identify majority of the main components of the BP above the clavicle, including the T1 ventral ramus and the formation of the inferior trunk, using high definition ultrasound imaging. TRIAL REGISTRATION NUMBER: ChiCTR1900021749.

Ultrasound-Guided Infraclavicular Brachial Plexus Block: Prospective Randomized Comparison of the Lateral Sagittal and Costoclavicular Approach.

BACKGROUND AND OBJECTIVES: It has recently been proposed that an infraclavicular brachial plexus block (BPB) at the costoclavicular (CC) space may overcome some of the limitations of the lateral sagittal (LS) approach. In this study, we hypothesized that the CC approach will produce faster onset of sensory blockade of the 4 major terminal nerves of the brachial plexus than the LS approach. METHODS: Forty patients undergoing elective upper extremity surgery under a BPB were randomized to receive either the LS (Gp-LS, n = 20) or CC approach (Gp-CC, n = 20) for infraclavicular BPB. Twenty-five milliliters of 0.5% ropivacaine was used for the BPB in both study groups. Sensory-motor blockade of the ipsilateral median, radial, ulnar, and musculocutaneous nerves was assessed by a blinded observer at regular intervals for 45 minutes after the block. Sensory block was assessed using a verbal rating scale (0-100) and motor block using a 3-point qualitative scale (0-2). Onset of sensory (primary outcome variable) and motor blockade was defined as the time it took to achieve a sensory verbal rating scale of 30 or less and motor grade of 1 or less, respectively. Time to readiness for surgery was defined as the time it took to achieve a sensory score of 30 or less and motor grade of 1 or less in all the 4 nerves tested. RESULTS: The overall sensory onset time (median [interquartile range]) was significantly faster (P = 0.004) in Gp-CC (10 [10-26.25] minutes) than in Gp-LS (20 [15-30] minutes). The overall sensory score was significantly lower in Gp-CC than in Gp-LS at 5 (P < 0.001), 10 (P = 001), 15 (P = 0.001), and 20 (P = 0.04) minutes after the BPB. The overall motor score was significantly lower (P = 0.009) in Gp-CC than in Gp-LS at 10 minutes after the BPB. There were more (P = 0.04) patients with complete sensory-motor blockade at 20 minutes after the BPB in Gp-CC (25%) than in Gp-LS (0%). Time to readiness for surgery was also significantly faster (P = 0.002) in Gp-CC (10 [10-26.5] minutes) than in Gp-LS (20 [15-30] minutes). CONCLUSIONS: The CC approach for infraclavicular BPB produces faster onset of sensory blockade and earlier readiness for surgery than the LS approach. CLINICAL TRIAL REGISTRATION: This study was registered at the Centre for Clinical Trials of The Chinese University of Hong Kong, identifier CUHK_CCT00389.

Ultrasound-Guided Costoclavicular Brachial Plexus Block: Sonoanatomy, Technique, and Block Dynamics.

BACKGROUND AND OBJECTIVES: This study aimed to describe in detail the relevant sonoanatomy, technique, and block dynamics of an ultrasound-guided costoclavicular brachial plexus block (BPB). METHODS: Thirty patients scheduled for hand or forearm surgery under a BPB underwent transverse ultrasound imaging of the medial infraclavicular fossa to identify the cords of the brachial plexus at the costoclavicular space (CCS). An ultrasound-guided BPB was then performed at the CCS with 20 mL of 0.5% ropivacaine. Sensory-motor blockade of the ipsilateral median, radial, ulnar, and musculocutaneous nerves were assessed at regular intervals for 30 minutes after the injection. Successful block was defined as being able to complete surgery under the BPB. RESULTS: The CCS was visualized as a well-defined intermuscular space lying deep and posterior to the mid-point of the clavicle. The cords of the brachial plexus were clustered together lateral to the axillary artery within the CCS. The costoclavicular BPB was successfully performed in all patients, and the median onset time for sensory and motor blockade of all the 4 nerves was 5 [5-15] and 5 [5-10] minutes, respectively. Complete sensory blockade of all the 4 nerves was achieved in 30 [20-30] minutes, and the BPB was successful in 29 (97%) of 30 patients. There were no complications directly related to the technique or the local anesthetic injection. CONCLUSIONS: This report describes a novel technique of infraclavicular BPB at the costoclavicular space that produces rapid onset of BPB. Future research should compare the safety and efficacy of this new technique with the traditional lateral sagittal infraclavicular BPB.

Factors affecting intraoperative blood loss during liver resection.

OBJECTIVE: Liver resection might be associated with significant blood loss and required blood transfusion. Many strategies were introduced to reduce blood loss during liver resection. Central venous pressure (CVP) was considered one of the factors affecting blood loss. The objective of the present study was to evaluate the factors correlated with blood loss during liver resection surgery including CVP MATERIAL AND METHOD: Between July 2008 and July 2010, medical and anesthetic records of patients who were admitted to King Chulalongkorn Memorial Hospital for more than one segment resection of the liver were retrospectively reviewed Factors potentially affecting blood loss including patient characteristics, surgical aspects, and anesthetic aspects in particular CVP were analyzed by regression analysis to explore the correlation with intraoperative blood loss. RESULTS: One hundred thirteen patients were included and analyzed. The mean intraoperative blood loss was 836.46+/-762.85 ml. The mean, maximum, and minimum values of CVP measured during liver resection were 7.36+/-3.26, 11.17+/-3.81, and 5.10+/-2.81 mmHg, respectively. On multiple regression analysis, the operative time and male patients were associated with blood loss. The other factors and CVP were not significantly correlated. CONCLUSION: The present study suggested that operation time and gender were the predictors of intraoperative blood loss in more than one segment resection of the liver In addition, CVP was not the important factor in predicting blood loss.