Adductor canal blocks: changing practice patterns and associated quality profile.

BACKGROUND: Femoral nerve blocks have been the gold standard approach for post-operative analgesia following total knee arthroplasty; however, the adductor canal block has recently gained popularity due to less block-induced motor weakness. The primary aim of this time-series analysis was to identify whether regional anesthesia practice changes have occurred for total knee arthroplasty. Our secondary aim was to assess for possible associated changes in safety and quality. METHODS: Using a 20-member clinical registry, we examined the practice patterns and safety around the performance of adductor canal blocks for all total knee arthroplasties between 18 July 2011 to 9 October 2015. To obtain more information about changes in quality associated with this practice transition, we analyzed clinical outcomes data surrounding all primary total knee arthroplasties from the largest contributing institution. RESULTS: A total of 6921 blocks were performed for 4822 primary and revision total knee arthroplasties (TKAs). Across the registry, adductor canal block utilization for TKA increased. This was not associated with any increase in immediate or recovery room-related complications. When analyzing unilateral primary TKAs from the largest surgical volume center (n = 766), there were no statistically significant changes in numeric rating scale scores (5.4 to 4.6, P value = 0.004), length of stay (3.0 to 2.8 days, P value = 0.3), or 30-day hospital re-evaluations for pain (2.8-4.9%, P value = 0.1). CONCLUSION: There was a large increase in the utilization of adductor canal blockade for TKAs among participating registry members. This change in practice was not associated with significant changes in safety or quality.

Design and validation of the Regional Anaesthesia Procedural Skills Assessment Tool.

The aim of this study was to create and evaluate the validity, reliability and feasibility of the Regional Anaesthesia Procedural Skills tool, designed for the assessment of all peripheral and neuraxial blocks using all nerve localisation techniques. The first phase was construction of a 25-item checklist by five regional anaesthesia experts using a Delphi process. This checklist was combined with a global rating scale to create the tool. In the second phase, initial validation by 10 independent anaesthetists using a test-retest methodology was successful (Cohen kappa ≥ 0.70 for inter-rater agreement, scores between test to retest, paired t-test, p > 0.12). In the third phase, 70 clinical videos of trainees were scored by three blinded international assessors. The RAPS tool exhibited face validity (p < 0.026), construct validity (p < 0.001), feasibility (mean time to score < 3.9 min), and overall reliability (intraclass correlation coefficient 0.80 (95% CI 0.67-0.88)). The Regional Anaesthesia Procedural Skills tool used in this study is a valid and reliable assessment tool to score the performance of trainees for regional anaesthesia.

Psychometric evaluation of a direct observation of procedural skills assessment tool for ultrasound-guided regional anaesthesia.

Assessment tools must be investigated for reliability, validity and feasibility before being implemented. In 2013, the Australian and New Zealand College of Anaesthetists introduced workplace-based assessments, including a direct observation of a procedural skills assessment tool. The objective of this study was to evaluate the psychometric properties of this assessment tool for ultrasound-guided regional anaesthesia. Six experts assessed 30 video-recorded trainee performances of ultrasound-guided regional anaesthesia. Inter-rater reliability, assessed using absolute agreement intraclass correlation coefficients, varied from 0.10 to 0.49 for the nine individual nine-point scale items, and was 0.25 for a 'total score' of all items. Internal consistency was measured by correlation between 'total score' and 'overall performance' scale item (r = 0.68, p < 0.001). Construct validity was demonstrated by the 'total score' correlating with trainee experience (r = 0.51, p = 0.004). The mean time taken to complete assessments was 6 min 35 s.

Pre-Flight Calibration of the Mars 2020 Rover Mastcam Zoom (Mastcam-Z) Multispectral, Stereoscopic Imager.

The NASA Perseverance rover Mast Camera Zoom (Mastcam-Z) system is a pair of zoomable, focusable, multi-spectral, and color charge-coupled device (CCD) cameras mounted on top of a 1.7 m Remote Sensing Mast, along with associated electronics and two calibration targets. The cameras contain identical optical assemblies that can range in focal length from 26 mm ( 25.5 ∘ × 19.1 ∘ FOV ) to 110 mm ( 6.2 ∘ × 4.2 ∘ FOV ) and will acquire data at pixel scales of 148-540 µm at a range of 2 m and 7.4-27 cm at 1 km. The cameras are mounted on the rover's mast with a stereo baseline of 24.3 ± 0.1  cm and a toe-in angle of 1.17 ± 0.03 ∘ (per camera). Each camera uses a Kodak KAI-2020 CCD with 1600 × 1200 active pixels and an 8 position filter wheel that contains an IR-cutoff filter for color imaging through the detectors' Bayer-pattern filters, a neutral density (ND) solar filter for imaging the sun, and 6 narrow-band geology filters (16 total filters). An associated Digital Electronics Assembly provides command data interfaces to the rover, 11-to-8 bit companding, and JPEG compression capabilities. Herein, we describe pre-flight calibration of the Mastcam-Z instrument and characterize its radiometric and geometric behavior. Between April 26 t h and May 9 t h , 2019, ∼45,000 images were acquired during stand-alone calibration at Malin Space Science Systems (MSSS) in San Diego, CA. Additional data were acquired during Assembly Test and Launch Operations (ATLO) at the Jet Propulsion Laboratory and Kennedy Space Center. Results of the radiometric calibration validate a 5% absolute radiometric accuracy when using camera state parameters investigated during testing. When observing using camera state parameters not interrogated during calibration (e.g., non-canonical zoom positions), we conservatively estimate the absolute uncertainty to be < 10 % . Image quality, measured via the amplitude of the Modulation Transfer Function (MTF) at Nyquist sampling (0.35 line pairs per pixel), shows MTF Nyquist = 0.26 - 0.50 across all zoom, focus, and filter positions, exceeding the > 0.2 design requirement. We discuss lessons learned from calibration and suggest tactical strategies that will optimize the quality of science data acquired during operation at Mars. While most results matched expectations, some surprises were discovered, such as a strong wavelength and temperature dependence on the radiometric coefficients and a scene-dependent dynamic component to the zero-exposure bias frames. Calibration results and derived accuracies were validated using a Geoboard target consisting of well-characterized geologic samples. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11214-021-00795-x.

The Mars 2020 Perseverance Rover Mast Camera Zoom (Mastcam-Z) Multispectral, Stereoscopic Imaging Investigation.

Mastcam-Z is a multispectral, stereoscopic imaging investigation on the Mars 2020 mission's Perseverance rover. Mastcam-Z consists of a pair of focusable, 4:1 zoomable cameras that provide broadband red/green/blue and narrowband 400-1000 nm color imaging with fields of view from 25.6° × 19.2° (26 mm focal length at 283 µrad/pixel) to 6.2° × 4.6° (110 mm focal length at 67.4 µrad/pixel). The cameras can resolve (≥ 5 pixels) ∼0.7 mm features at 2 m and ∼3.3 cm features at 100 m distance. Mastcam-Z shares significant heritage with the Mastcam instruments on the Mars Science Laboratory Curiosity rover. Each Mastcam-Z camera consists of zoom, focus, and filter wheel mechanisms and a 1648 × 1214 pixel charge-coupled device detector and electronics. The two Mastcam-Z cameras are mounted with a 24.4 cm stereo baseline and 2.3° total toe-in on a camera plate ∼2 m above the surface on the rover's Remote Sensing Mast, which provides azimuth and elevation actuation. A separate digital electronics assembly inside the rover provides power, data processing and storage, and the interface to the rover computer. Primary and secondary Mastcam-Z calibration targets mounted on the rover top deck enable tactical reflectance calibration. Mastcam-Z multispectral, stereo, and panoramic images will be used to provide detailed morphology, topography, and geologic context along the rover's traverse; constrain mineralogic, photometric, and physical properties of surface materials; monitor and characterize atmospheric and astronomical phenomena; and document the rover's sample extraction and caching locations. Mastcam-Z images will also provide key engineering information to support sample selection and other rover driving and tool/instrument operations decisions.

Acute compartment syndrome of the lower limb and the effect of postoperative analgesia on diagnosis.

Acute compartment syndrome can cause significant disability if not treated early, but the diagnosis is challenging. This systematic review examines whether modern acute pain management techniques contribute to delayed diagnosis. A total of 28 case reports and case series were identified which referred to the influence of analgesic technique on the diagnosis of compartment syndrome, of which 23 discussed epidural analgesia. In 32 of 35 patients, classic signs and symptoms of compartment syndrome were present in the presence of epidural analgesia, including 18 patients with documented breakthrough pain. There were no randomized controlled trials or outcome-based comparative trials available to include in the review. Pain is often described as the cardinal symptom of compartment syndrome, but many authors consider it unreliable. Physical examination is also unreliable for diagnosis. There is no convincing evidence that patient-controlled analgesia opioids or regional analgesia delay the diagnosis of compartment syndrome provided patients are adequately monitored. Regardless of the type of analgesia used, a high index of clinical suspicion, ongoing assessment of patients, and compartment pressure measurement are essential for early diagnosis.

Determination of spread of injectate after ultrasound-guided transversus abdominis plane block: a cadaveric study.

BACKGROUND: The transversus abdominis plane (TAP) block is a new regional anaesthesia technique that provides analgesia after abdominal surgery. It involves injection of local anaesthetic into the plane between the transversus abdominis and the internal oblique muscles. The TAP block can be performed using a landmark technique through the lumbar triangle or with ultrasound guidance. The goal of this anatomical study with dye injection into the TAP and subsequent cadaver dissections was to establish the likely spread of local anaesthesia in vivo and the segmental nerve involvement resulting from ultrasound-guided TAP block. METHODS: An ultrasound-guided injection of aniline dye into the TAP was performed for each hemi-abdominal wall of 10 unembalmed human cadavers and this was followed by dissection to determine the extent of dye spread and nerve involvement in the dye injection. RESULTS: After excluding one pilot specimen and one with advanced tissue decomposition, 16 hemi-abdominal walls were successfully injected and dissected. The lower thoracic nerves (T10-T12) and first lumbar nerve (L1) were found emerging from posterior to anterior between the costal margin and the iliac crest. Segmental nerves T10, T11, T12, and L1 were involved in the dye in 50%, 100%, 100%, and 93% of cases, respectively. CONCLUSIONS: This anatomical study shows that an ultrasound-guided TAP injection cephalad to the iliac crest is likely to involve the T10-L1 nerve roots, and implies that the technique may be limited to use in lower abdominal surgery.

Spread of injectate after ultrasound-guided subcostal transversus abdominis plane block: a cadaveric study.

Ultrasound-guided transversus abdominis plane (TAP) block can be performed using a subcostal technique. This technique was simulated using dye injection in cadavers in order to determine segmental nerve involvement and spread of injectate using either single or multiple-injection techniques. Dye most commonly spread to affect T9 and T10 nerves with the single injection technique and T9, T10 and T11 with multiple injections. The median (IQR [range]) spread of dye was 60 (36-63 [32-78]) cm(2) using the single-injection technique and 90 (85-96 [72-136]) cm(2), in the multiple-injection technique, and this difference was statistically significant (p = 0.003). These results indicate that ultrasound-guided subcostal TAP block will involve nerve roots T9, T10 and T11 and that a multiple-injection technique may block more segmental nerves and increase spread of injectate.

Refining the course of the thoracolumbar nerves: a new understanding of the innervation of the anterior abdominal wall.

Previous descriptions of the thoracolumbar spinal nerves innervating the anterior abdominal wall have been inconsistent. With modern surgical and anesthetic techniques that involve or may damage these nerves, an improved understanding of the precise course and variability of this anatomy has become increasingly important. The course of the nerves of the anterior abdominal is described based on a thorough cadaveric study and review of the literature. Twenty human cadaveric hemi-abdominal walls were dissected to map the course of the nerves of the anterior abdominal wall. Dissection included a comprehensive tracing of nerves and their branches from their origins in five specimens. The branching pattern and course of all nerves identified were described. All thoracolumbar nerves that innervate the anterior abdominal wall were found to travel as multiple mixed segmental nerves, which branch and communicate widely within the transversus abdominis plane (TAP). This communication may occur at multiple locations, including large branch communications anterolaterally (intercostal plexus), and in plexuses that run with the deep circumflex iliac artery (DCIA) (TAP plexus) and the deep inferior epigastric artery (DIEA) (rectus sheath plexus). Rectus abdominis muscle is innervated by segments T6-L1, with a constant branch from L1. The umbilicus is always innervated by a branch of T10. As such, identification or damage to individual nerves in the TAP or within rectus sheath is unlikely to involve single segmental nerves. An understanding of this anatomy may contribute to explaining clinical outcomes and preventing complications, following TAP blocks for anesthesia and DIEA perforator flaps for breast reconstruction.

The effectiveness of regional anaesthesia before and after the introduction of a dedicated regional anaesthesia service incorporating a block room.

Dedicated regional anaesthesia services incorporating block rooms and/or block teams may facilitate theatre efficiency and improve training in regional anaesthesia. Currently, it is unknown if a dedicated regional anaesthesia service improves the effectiveness of regional anaesthesia. In November 2013, the Royal Brisbane and Women's Hospital established a dedicated regional anaesthesia service comprising a block team and a block room. Pre-intervention (conventional model of care) registry data was retrospectively compared with post-intervention (dedicated regional anaesthesia service) audit data, with regard to pain and opioid requirement in the post-anaesthesia care unit (PACU). The primary outcome was inadequate analgesia, defined as a numerical rating scale (NRS; 0, no pain; 10, worst pain imaginable) for pain >5 in the PACU. Pre- and post-intervention, 43.7% and 27.7% of patients respectively reported a NRS >5 (P <0.001). A difference in the type of blocks and surgery performed may have accounted for the improved outcome seen post-intervention. After adjustment for American Society of Anesthesiologists physical status, block type and surgery type, the odds ratio of having inadequate analgesia (NRS >5) was 0.54 (95% confidence interval 0.39 to 0.76) for post-intervention compared to pre-intervention. Secondary outcomes examined pre- and post-intervention were the absence of pain (39.3% and 55.1% of patients, respectively, P <0.001), systemic opioid analgesia requirement (48.6% and 30.5% of patients respectively, P <0.001) and median maximum NRS (4 [interquartile range (IQR) 0 to 8] and 0 [IQR 0 to 6] respectively, P <0.001). A dedicated regional anaesthesia service was associated with improved effectiveness of regional anaesthesia.

Immunosuppressive effects of 3-methylcholanthrene given intratracheally in various inbred strains of mice.

The immunosuppressive effects of 3-methylcholanthrene (MCA) given intratracheally have been shown to correlate with susceptibility of some inbred strains of mice to MCA-induced carcinogenesis. In susceptible strains of mice, C3Hf and C57BL/6, intratracheal administration of MCA resulted in profound systemic immunodepression. This effect was not observed in resistant DBA/2 mice. This immunodepressive effect correlated with the inducibility of the aryl hydrocarbon hydroxylase enzyme complex and the inducibility of pulmonary tumors by MCA.

Reliability of the direct observation of procedural skills assessment tool for ultrasound-guided regional anaesthesia.

The Direct Observation of Procedural Skills (DOPS) form is used as a workplace-based assessment tool in the current Australian and New Zealand College of Anaesthetists curriculum. The objective of this study was to evaluate the reliability of DOPS when used to score trainees performing ultrasound-guided regional anaesthesia. Reliability of an assessment tool is defined as the reproducibility of scores given by different assessors viewing the same trainee. Forty-nine anaesthetists were recruited to score two scripted videos of trainees performing a popliteal sciatic nerve block and an axillary brachial plexus block. Reliability, as measured by intraclass correlation coefficients, was -0.01 to 0.43 for the individual items in DOPS, and 0.15 for the 'Overall Performance for this Procedure' item. Assessors demonstrated consistency of scoring within DOPS, with significant correlation of sum of individual item scores with the 'Overall Performance for this Procedure' item (r=0.78 to 0.80, P<0.001), and with yes versus no responses to the 'Was the procedure completed satisfactorily?' item (W=24, P=0.0004, Video 1, and W=65, P=0.003, Video 2). While DOPS demonstrated a good degree of internal consistency in this setting, inter-rater reliability did not reach levels generally recommended for formative assessment tools. Feasibility of the form could be improved by removing the 'Was the procedure completed satisfactorily?' item without loss of information.

A randomised controlled trial comparing three analgesia regimens following total knee joint replacement: continuous femoral nerve block, intrathecal morphine or both.

This randomised controlled trial compared three analgesia regimens following primary unilateral total knee joint replacement: continuous femoral nerve block (CFNB), intrathecal morphine (ITM), and both. The primary outcome was pain ratings over the first 24 hours. Secondary outcomes included morphine consumption, nausea, pruritus and sedation ratings, oxygen saturation (SpO2) ratings, and ability to mobilise postoperatively. All patients received a spinal anaesthetic and a postoperative patient-controlled morphine pump. Patients were randomised to receive CFNB, ITM, or both. In patients with no CFNB, the use of ITM was blinded. Eighty-one patients were randomised and there were no withdrawals. At 24 hours, the ITM-only group had higher pain ratings than either of the other groups (P=0.04 versus CFNB, P=0.01 versus combination). In the 18 to 24 hour period, the ITM group used more morphine than either of the other groups. There were no statistically significant differences in pain ratings or morphine consumption at earlier time intervals. The ITM group were less likely to be able to sit out of bed on day one. Patients who received ITM were more likely to have pruritus. There were no statistically significant differences in nausea, SpO2or sedation ratings. This study showed that a CFNB resulted in reduced pain and was also associated with less morphine consumption and improved mobilisation at 24 hours compared to ITM. This study did not show any statistically significant differences between CFNB alone and CFNB+ITM.

Evidence that M1 muscarinic receptors enhance noradrenaline release in mouse atria by activating protein kinase C.

1. The M1 selective muscarinic agonist, McNeil A 343, enhanced the electrically evoked release of noradrenaline from postganglionic sympathetic nerves in mouse atria. This has been found previously to be due to activation of muscarinic receptors of the M1 subtype, probably located on sympathetic nerve terminals. The present study investigated the signal transduction mechanisms involved in the release-enhancing effects of McNeil A 343. The release of noradrenaline from mouse atria was assessed by measuring the electrically-induced (3 Hz, 60 s) outflow of radioactivity from atria which had been pre-incubated with [3H]-noradrenaline. 2. 8-Bromo cyclic AMP in the presence of IBMX was used to enhance maximally S-I noradrenaline release through cyclic AMP-dependent mechanisms. However, the facilitatory effect of McNeil A 343 (10 microM) was not different from the effect in the absence of these drugs, suggesting that McNeil A 343 enhances noradrenaline release independently of the cyclic AMP system. Furthermore, the release-enhancing effect of McNeil A 343 (10 microM) on noradrenaline release was also not altered by the 5-lipoxygenase inhibitor, BW A4C. 3. The facilitatory effect of McNeil A 343 was not altered in the presence of drugs (trifluoperazine, W7, and calmidazolium) which inhibit calmodulin-dependent processes, suggesting that the mechanisms of action of McNeil A 343 does not depend on calmodulin. 4. It was considered likely that the facilitatory effect of McNeil A 343 on noradrenaline release may be due to activation of protein kinase C, since activators of protein kinase C enhance noradrenaline release. The facilitatory effect of McNeil A 343 was abolished by the non-selective protein kinase C inhibitor,K-252a. To investigate further the involvement of protein kinase C, mouse atria were chronically incubated (9-O h) with the protein kinase C activator, 4 beta-phorbol dibutyrate (1.0 microM) in order to down-regulate protein kinase C activity. In protein kinase C-down-regulated atria, the facilitatory effect of McNeil A 343 (30 microM) was abolished. Incubation with 4 alpha-phorbol dibutyrate which does not affect protein kinase C did not reduce the facilitatory effect of McNeil A 343. This provides evidence that activation of protein kinase C is involved in the signal transduction process of McNeil A 343.

Noradrenaline release and the effect of endogenous activation of the phospholipase C/protein kinase C signalling pathway in rat atria.

1. It has been proposed that protein kinase C (PKC) in sympathetic nerves is activated during action-potential evoked release of noradrenaline and helps maintain transmitter output. We studied this phenomenon further in rat atria radiolabelled with [3H]-noradrenaline. 2. Noradrenaline release was elevated by continuous electrical stimulation of the atria for 10 min at either 5 or 10 Hz. Two inhibitors of PKC, polymyxin B (21 microM) and Ro 318220 (3 microM), markedly inhibited the release of noradrenaline but only at the higher stimulation frequency. 3. Further experiments were conducted with 10 Hz stimulation but for shorter train durations. In this case polymyxin B inhibited noradrenaline release during a 10 or 15 s train of impulses but not during a 5 s train. This suggests that PKC effects are induced during the stimulation train by some process. 4. The diacylglycerol kinase inhibitor R59949 (10 microM), which prevents the breakdown of diacylglycerol, enhanced noradrenaline release elicited by stimulation at 10 Hz for 10 or 15 s. This effect was not seen if polymyxin B was present and suggests that diacylglycerol is the endogenous activator of PKC. 5. The source of the diacylglycerol may be through phospholipase C pathways, since the phospholipase C inhibitor U73122 (3 microM) inhibited noradrenaline release at 10 Hz for 10 s and the effect was not seen if polymyxin B was also present. 6. It is unlikely that phospholipase D is the source of diacylglycerol. Although the phospholipase D inhibitor wortmannin (1 microM) inhibited noradrenaline release, this effect was still observed in the presence of polymyxin B. Furthermore ethanol, which inhibits diacylglycerol formation by phospholipase D, had no effect on noradrenaline release. 7. We therefore suggest that during a train of high frequency pulses phospholipase C is activated and this results in the production of diacylglycerol which in turn activates PKC. This enables the neurones to maintain transmitter release at a high level.

Trifluoperazine and calmidazolium have multiple actions on the release of noradrenaline from sympathetic nerves of mouse atria.

The aim of this study was to determine whether the calmodulin inhibitors trifluoperazine (TFP) and calmidazolium (CMZ) could decrease the action-potential-evoked release of noradrenaline from mouse isolated atria incubated with [3H]-noradrenaline in support of the hypothesis that calmodulin is involved in neurotransmitter release. TFP (10 microM and 30 microM) significantly enhanced stimulation-induced (S-I) outflow of radioactivity from mouse atria but had no effect at 1.0 microM or 70 microM. TFP (70 microM) also significantly increased the spontaneous outflow of radioactivity. The facilitatory effect of TFP (10 microM) on S-I outflow of radioactivity persisted in either the presence of 3-isobutyl-1-methylxanthine (100 microM) or atropine (0.3 microM) indicating that this effect of TFP was not mediated through either inhibition of phosphodiesterases or through interference with presynaptic muscarinic receptors, respectively. In the presence of phentolamine, the facilitatory effect of TFP (10 microM) on S-I outflow was reduced but there was no effect on S-I outflow at 70 microM. However, in the presence of a combination of both phentolamine (1.0 microM) and the neuronal uptake blocker desipramine (1.0 microM) a significant inhibitory effect of TFP (70 microM) on the S-I outflow of radioactivity was observed, indicating that effects of TFP on presynaptic alpha-adrenoceptors and neuronal uptake had disguised an inhibitory effect on S-I noradrenaline release. Another inhibitor of the Ca(2+)-calmodulin complex, calmidazolium (CMZ, 10 microM) inhibited the S-I outflow of radioactivity but had no effect at 1.0 microM. However, CMZ (10 microM) also induced a concomitant increase in the spontaneous outflow of radioactivity.(ABSTRACT TRUNCATED AT 250 WORDS)

The duration of normal visual exposure necessary to prevent form deprivation myopia in chicks.

The aim of this study was to determine the minimum daily period of exposure to normal visual stimulation required to prevent occlusion induced myopia in chicks. Chicks were treated with monocular translucent occlusion in a 12 hr light/12 hr dark cycle. Occluders were removed for 0 (constant occlusion), 15, 20, 30, 40, 60, 75, 90, 120, 150, 240 or 720 (no occlusion) minutes each day for either 2 or 3 weeks. Fellow eyes and the eyes of normal chicks (bilaterally unoccluded) were used as controls. Occlusion-induced myopia and axial elongation were found to decrease significantly (P < 0.01) with increasing daily exposure to normal visual stimulation. Application of a time series equation to the data estimates that 30 and 130 min of normal visual exposure per day reduces myopia by 50 and 95% respectively. This study demonstrated that the regulation of ocular growth is affected strongly by short periods of normal visual stimulation in the presence of long periods of abnormal stimulation.