Dry spinal tap during real-time ultrasound-guided paramedian spinal injection with patient in the lateral decubitus position: A single-centre retrospective study.

BACKGROUND: Real-time ultrasound-guided (USG) spinal injection is generally performed via the paramedian sagittal oblique (PMSO) ultrasound window. OBJECTIVE: The aim of this retrospective study was to draw attention to the occurrence of 'dry tap' during real-time USG spinal injection. DESIGN: Single-centre retrospective study. SETTING: University teaching hospital, Hong Kong, China. PATIENTS: Data from 113 patients (aged 69.2 ±â€Š18.0 years and BMI 22.3 ±â€Š3.6 kg m-2) of American Society of Anesthesiologists physical status 1 to 3 scheduled for surgery under neuraxial blockade between 2007 to 2017 were reviewed. INTERVENTIONS: Real-time USG spinal injections or combined spinal-epidural (CSE) using the PMSO ultrasound window with the patient in the lateral decubitus position and the spinal needle inserted from the nondependent side were studied. MAIN OUTCOME MEASURES: 'Dry tap' was defined as a failure of cerebrospinal fluid (CSF) to efflux from the hub of the needle, within 3 min, with the spinal needle visualised sonographically within the thecal sac. 'Slow CSF efflux' was defined as efflux of CSF within 1 to 3 min. Irrespective of whether it was a 'dry tap' or 'slow CSF efflux', the planned dose of local anaesthetic was injected through the spinal needle. RESULTS: The combined incidence of 'dry tap' and 'slow CSF efflux' was 23.8% (27/113) with an individual incidence for each event of 9.7% (11/113) and 14.2% (16/113), respectively. Under the conditions of this study, successful spinal anaesthesia developed in all patients. CONCLUSION: 'Dry tap' occurs in 9.7% of cases during real-time USG spinal injection using the PMSO ultrasound window, with the patient in the lateral decubitus position and the spinal needle inserted from the nondependent side. TRIAL REGISTRATION: ChiCTR-IOR-1800019011, Chinese Clinical Trials Registry (www.chictr.org.cn).

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).

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.

Ipsilateral hemidiaphragmatic paresis after a supraclavicular and costoclavicular brachial plexus block: A randomised observer blinded study.

BACKGROUND: The costoclavicular brachial plexus block (BPB) produces faster onset of sensory motor blockade than the lateral sagittal approach. However, the incidence of phrenic nerve palsy (PNP) after a costoclavicular BPB is not known. OBJECTIVES: The current study compared the incidence of ipsilateral hemidiaphragmatic paresis, and thus PNP, between a supraclavicular and costoclavicular BPB. DESIGN: Randomised observer blinded study. SETTING: Operating room. PATIENTS: Forty patients undergoing right-sided upper extremity surgery. INTERVENTION: All patients received either a supraclavicular group or costoclavicular group BPB using 20 ml of an equal mixture of 0.5% bupivacaine and 2% lidocaine with 1 : 200 000 epinephrine. MAIN OUTCOME MEASURES: Measurements included ipsilateral hemidiaphragmatic excursion and peak expiratory flow rate (PEFR) taken before and at 30 min after the BPB. Diaphragmatic excursion was measured using M-mode ultrasound during normal breathing, deep breathing and with the sniff manoeuvre. Ipsilateral PNP was defined as a reduction in hemidiaphragmatic excursion by at least 50% during deep breathing at 30 min after the BPB. RESULTS: The incidence of ipsilateral PNP was lower (P = 0.008) in the costoclavicular group (5%) than in the supraclavicular group (45%). Fewer (P = 0.04) patients in the costoclavicular group [1(5%)] exhibited a positive sniff test, with paradoxical movement of the diaphragm, than in the supraclavicular group [7(35%)]. PEFRs were similar (P = 0.09) between the groups. When ipsilateral hemidiaphragmatic paresis was present, the median reduction in PEFR was 32% (interquartile range 23.6 to 45.5%). CONCLUSION: Costoclavicular BPB produces a lower incidence of ipsilateral PNP than a supraclavicular BPB. NAME OF REGISTRY: Clinical Trial Registry of India. IDENTIFIER: CTRI/2017/09/009763.

Sonographic tracking of trunk nerves: essential for ultrasound-guided pain management and research.

Delineation of architecture of peripheral nerves can be successfully achieved by high-resolution ultrasound (US), which is essential for US-guided pain management. There are numerous musculoskeletal pain syndromes involving the trunk nerves necessitating US for evaluation and guided interventions. The most common peripheral nerve disorders at the trunk region include thoracic outlet syndrome (brachial plexus), scapular winging (long thoracic nerve), interscapular pain (dorsal scapular nerve), and lumbar facet joint syndrome (medial branches of spinal nerves). Until now, there is no single article systematically summarizing the anatomy, sonographic pictures, and video demonstration of scanning techniques regarding trunk nerves. In this review, the authors have incorporated serial figures of transducer placement, US images, and videos for scanning the nerves in the trunk region and hope this paper helps physicians familiarize themselves with nerve sonoanatomy and further apply this technique for US-guided pain medicine and research.

Low-Volume Brachial Plexus Block Providing Surgical Anesthesia for Distal Arm Surgery Comparing Supraclavicular, Infraclavicular, and Axillary Approach: A Randomized Observer Blind Trial.

Background. Distal arm surgery is widely performed under regional anesthesia with brachial plexus block. The preponderance of evidence for the efficacy relies upon injection of local anesthetic in excess of 30 mL. We aimed to compare three different ultrasound-guided brachial plexus block techniques restricting the total volume to 20 mL. Methods. 120 patients were prospectively randomized to ultrasound-guided brachial plexus block with 20 mL ropivacaine 0.75% at either the supraclavicular, infraclavicular, or axillary level. Multiinjection technique was performed with all three approaches. Primary outcome measure was performance time. Results. Performance time and procedural pain were similar between groups. Needle passes and injection numbers were significantly reduced in the infraclavicular group (P < 0.01). Nerve visibility was significantly reduced in the axillary group (P = 0.01). Success-rate was significantly increased in the supraclavicular versus the axillary group (P < 0.025). Total anesthesia-related time was significantly reduced in the supraclavicular compared to the infraclavicular group (P < 0.01). Block duration was significantly increased in the infraclavicular group (P < 0.05). No early adverse effects occurred. Conclusion. Supraclavicular and infraclavicular blocks exhibited favorable characteristics compared to the axillary block. Supraclavicular brachial plexus block with the multiinjection intracluster technique exhibited significantly reduced total anesthesia-related time and higher success rate without any early adverse events.

The traditional vs "1:1:1" approach debate on massive transfusion in trauma should not be treated as a dichotomy.

Traditional transfusion guidelines suggest that fresh frozen plasma (FFP) should be given based on laboratory or clinical evidence of coagulopathy or acute loss of 1 blood volume. This approach tends to result in a significant lag time between the first units of erythrocytes and FFP in trauma requiring massive transfusion. In severe trauma, observational studies have found an association between increased survival and aggressive use of FFP and platelets such that FFP:platelet:erythrocyte ratio approaches 1:1:1 to 2 from the first units of erythrocytes given. There are considerable concerns over either approach, and no randomized controlled trials have been published comparing the 2 approaches. Nowadays, trauma clinicans are incorporating the strenghts of both approaches and are no longer treating them as a dichotomy. Specifically, "1:1:1" proponents have devised 1:1:1 activation criteria to minimize unnecessary FFP and platelet transfusion and are prepared to deactivate the protocol as soon as patient is stabilized. Similarly, 1:1:1 skeptics are more mindful of the need to be proactive about trauma coagulopathy and the inherent delays in FFP administration in trauma patients.

Age-related differences in the quantitative echo texture of the median nerve.

OBJECTIVES: Currently, there are no quantitative data on the echo texture of a peripheral nerve. This study was designed to objectively compare the differences in the echo texture of the median nerve in the young and the elderly. METHODS: The median nerves of 10 healthy young volunteers (<30 years old; group Y) and 10 elderly patients undergoing lower limb surgery (>60 years old; group E) were scanned at the mid forearm by a standardized protocol. The echo texture of a normalized median nerve image was analyzed for the echo intensity and spatial distribution of pixels. Noise in the image was reduced by using a median filter, and thresholding was performed thereafter. In the resultant binary image, the cross-sectional area, echo intensity, white area index, and black area index of the median nerve were determined by computerized texture analysis. RESULTS: The mean cross-sectional area of the median nerve in group E was significantly smaller than that in group Y (P = .002). The mean echo intensity and white area index in group E were significantly higher than those in group Y (P= .002 and .012). The mean black area index in group E was correspondingly significantly lower than that in group Y (P = .012). In group Y, the mean white area index was significantly lower than the black area index (P = .006) but not in group E (P = .213). CONCLUSIONS: There are significant differences in the echo texture of the median nerve between the young and the elderly. These differences may be due to age-related changes in the relative proportion of neural fascicles and connective tissue within the nerve.

Prevalence of survivor bias in observational studies on fresh frozen plasma:erythrocyte ratios in trauma requiring massive transfusion.

Observational studies on transfusion in trauma comparing high versus low plasma:erythrocyte ratio were prone to survivor bias because plasma administration typically started later than erythrocytes. Therefore, early deaths were categorized in the low plasma:erythrocyte group, whereas early survivors had a higher chance of receiving a higher ratio. When early deaths were excluded, however, a bias against higher ratio can be created. Survivor bias could be reduced by performing before-and-after studies or treating the plasma:erythrocyte ratio as a time-dependent covariate.We reviewed 26 studies on blood ratios in trauma. Fifteen of the studies were survivor bias-unlikely or biased against higher ratio; among them, 10 showed an association between higher ratio and improved survival, and five did not. Eleven studies that were judged survivor bias-prone favoring higher ratio suggested that a higher ratio was superior.Without randomized controlled trials controlling for survivor bias, the current available evidence supporting higher plasma:erythrocyte resuscitation is inconclusive.

Regional hemodynamic changes after an axillary brachial plexus block: a pulsed-wave Doppler ultrasound study.

BACKGROUND: Brachial plexus block (BPB) causes vasodilatation and an increase in blood flow to the ipsilateral upper limb. However, no reports have comprehensively evaluated the regional hemodynamic changes after a BPB. METHODS: Eight healthy adult patients who were scheduled for elective hand surgery had an ultrasound-guided axillary BPB for anesthesia. Regional hemodynamic parameters were measured in the ipsilateral brachial artery, using pulsed-wave Doppler (PWD) ultrasound before the block (0 minute) and at regular intervals for 30 minutes after the block. Skin temperature on the dorsum of the ipsilateral hand was also recorded at the same time intervals. Regional hemodynamic parameters that were measured in the brachial artery included peak systolic velocity (PSV, cm/s), end-diastolic velocity (EDV, cm/s), mean velocity (Vmean) and time-averaged mean velocity (TAVM, cm/s), ratio of PSV and EDV (S/D), diameter (d, cm), resistance index (RI), and pulsatility index (PI). Brachial artery blood flow (Q) was calculated as the product of TAVM and cross-sectional area. RESULTS: The ultrasound-guided axillary BPB was successful in all the patients studied. The earliest change after the BPB was a change in the morphology of the PWD spectral waveform from a triphasic to a monophasic waveform and an elevation in the diastolic blood flow velocity. Over time, there was also a significant increase in PSV, EDV, Vmean, TAVM, d, brachial artery blood flow, and skin temperature and a decrease in S/D ratio, RI, and PI. Most of these changes were seen as early as 5 minutes after the block. The increase in EDV (3.7-fold) was the most notable change, and it was greater (P < 0.05) than the increase in PSV (1.5-fold) and Vmean (2.8-fold). CONCLUSIONS: Regional hemodynamic changes that occur after an axillary BPB include a change in the morphology of the PWD spectral waveform, arterial vasodilatation, an increase in blood flow velocity, and an increase in blood flow through the ipsilateral brachial artery.

The medial-transverse approach for internal jugular vein cannulation: an example of lateral thinking.

BACKGROUND: Cannulation of the internal jugular vein (IJV) is traditionally performed using the central-longitudinal approach. Pneumothorax, carotid artery puncture, and failure to cannulate are uncommon, but by no means rare, complications. Ultrasound (US) guidance for IJV cannulation has reduced but not eliminated such complications. TECHNIQUE: We herein introduce a new approach, coined the "medial-transverse approach" due to the perpendicular angle at which the introducer needle is advanced toward the IJV from the median to lateral direction. DISCUSSION: The direction of the introducer needle is not toward the lung, thus virtually eliminating the possibility of pneumothorax. The image of the entire needle is seen when the US probe is typically orientated for a short-axis view of the IJV and carotid artery, thus improving the chance of uncomplicated IJV puncture. We have used this technique with apparent success in thousands of cases over the past 20 years in two different institutions. CONCLUSION: A modified IJV cannulation technique that seems to have unique advantages over traditional approaches has been described. This technique is compatible with the blind and US-guided approaches.

Acute pain management of patients with multiple fractured ribs: a focus on regional techniques.

PURPOSE OF REVIEW: Thoracic trauma leading to multiple fractured ribs (MFR) remains very common. Good analgesia may help to improve a patient's respiratory mechanics and to avoid intubation of the trachea for ventilatory support and therefore may dramatically alter the course of recovery. We herein review the analgesia options for patients with MFR. RECENT FINDINGS: For healthy patients with one to two fractured ribs, systemic analgesics may suffice. For more than three to four fractured ribs, studies and experience have reaffirmed the superior analgesia made possible with thoracic epidural, thoracic paravertebral, and intercostal blocks. From experience, interpleural block has significant drawbacks. Catheterization allows the continuation of analgesia for 2 or more days with just one block. Use of the landmark technique is usually satisfactory for accurate block placement but ultrasound and nerve stimulation are showing promise in further improving needle and catheter placement accuracy, especially in the presence of difficult anatomy. SUMMARY: Thoracic epidural, thoracic paravertebral, and intercostal blocks are the top choices for patients with MFR and they are of equivalent efficacy. Each has unique advantages and disadvantages. Our preference tends to be the thoracic paravertebral approach.

Gelatin-agar lumbosacral spine phantom: a simple model for learning the basic skills required to perform real-time sonographically guided central neuraxial blocks.

This report describes the preparation of a gelatin-agar spine phantom that was used for spinal sonography and to practice the hand-eye coordination skills required to perform sonographically guided central neuraxial blocks. The phantom was prepared by embedding a lumbosacral spine model into a mixture of gelatin and agar in a plastic box. Cellulose powder and chlorhexidine were also added to the mixture, after which it was allowed to solidify. Sonography of the osseous elements of the lumbosacral spine in the phantom was then performed, and their sonographic appearances were compared to those in volunteers. Simulated real-time sonographically guided paramedian spinal needle insertions were also performed in the phantom. The texture and echogenicity of the phantom were subjectively comparable to those of tissue in vivo. The osseous elements of the spine in the phantom were clearly delineated, and their sonographic appearances were comparable to those seen in vivo in the volunteers. During the simulated sonographically guided spinal injections, the needle could be clearly visualized, but the phantom provided little tactile feedback. In conclusion, the gelatin-agar spine phantom is a simple and inexpensive sonographic spine model that has a tissuelike texture and echogenicity. It can be used to study the osseous anatomy of the lumbar spine and practice the skills required to perform sonographically guided central neuraxial blocks.