Anatomical assessments of injectate spread stratified by the volume of the intertransverse process block at the T2 level.

BACKGROUND: This cadaveric study aimed to analyze injectate spread to target nerves during a single-injection, ultrasound-guided intertransverse process block. METHODS: An ultrasound-guided intertransverse process block with three different injectate volumes was administered to 12 cadavers. Each hemithorax was subjected to computer-generated random allocation of 10, 15, or 20 mL ultrasound-guided, single-injection intertransverse process block at the T2 vertebral level. Latex dye solution was injected into each hemithorax in accordance with the allocated volume. The presence of dye at the nerve root in the sympathetic chain and intercostal nerves at various injection levels was examined via dissection. RESULTS: Injectate spread into the dorsal rami was observed in seven of eight (87.5%), seven of eight (87.5%), and all eight (100%) of the 10, 15, and 20 mL specimens, respectively. In all 20 mL specimens, consistent staining of the dorsal rami, spinal nerve, and dorsal root ganglion was observed. CONCLUSIONS: An injectate volume of 20 mL was required for consistent staining of the dorsal rami, spinal nerve, and dorsal root ganglion in an intertransverse process block. Although an augmented injectate volume was associated with an increased likelihood of target nerve staining, consistent staining of the sympathetic ganglion, rami communicans, and ventral ramus was not observed, even at a volume of 20 mL. The current study presents initial findings suggesting that as opposed to a sympathetic ganglion block, a 20 mL intertransverse process block may act as a feasible substitute for dorsal root ganglion, spinal nerve, and medial branch blocks within a clinical context.

Rational design of hybrid sensor arrays combined synergistically with machine learning for rapid response to a hazardous gas leak environment in chemical plants.

Combinations of semiconductor metal oxide (SMO) sensors, electrochemical (EC) sensors, and photoionization detection (PID) sensors were used to discriminate chemical hazards on the basis of machine learning. Sensing data inputs were exploited in the form of either numerical or image data formats, and the classification of chemical hazards with high accuracy was achieved in both cases. Even a small amount of gas sensing or purging data (input for ∼30 s) input can be exploited in machine-learning-based gas discrimination. SMO sensors exhibit high performance even in a single-sensor mode, presumably because of the intrinsic cross-sensitivity of metal oxides, which is otherwise considered a major disadvantage of SMO sensors. EC sensors were enhanced through synergistic integration of sensor combinations with machine learning. For precision detection of multiple target analytes, a minimum number of sensors can be proposed for gas detection/discrimination by combining sensors with dissimilar operating principles. The Type I hybrid sensor combines one SMO sensor, one EC sensor, and one PID sensor and is used to identify NH3 gas mixed with sulfur compounds in simulations of NH3 gas leak accidents in chemical plants. The portable remote sensing module made with a Type I hybrid sensor and LTE module can identify mixed NH3 gas with a detection time of 60 s, demonstrating the potential of the proposed system to quickly respond to hazardous gas leak accidents and prevent additional damage to the environment.

Iliopsoas plane block does not improve pain after primary total hip arthroplasty in the presence of multimodal analgesia: a single institution randomized controlled trial.

BACKGROUND: The clinical analgesic efficacy of iliopsoas plane block remains a subject of discussion. This study aimed to assess the analgesic efficacy of iliopsoas plane block under general anesthesia using multimodal analgesia. METHODS: Fifty-six adult patients who underwent elective primary hip arthroplasty were enrolled. Patients were randomized to receive either a single-shot iliopsoas plane block (10 mL 0.75% ropivacaine with 1:200 000 epinephrine) or a sham block (10 mL normal saline). All patients received general anesthesia, multimodal analgesia (preoperative buprenorphine patch, 5 µg/h), intraoperative intravenous dexamethasone (8 mg) and nefopam (20 mg), and round-the-clock acetaminophen and celecoxib. The primary outcome was the numeric rating scale pain score at rest 6 hour after surgery. RESULTS: Iliopsoas plane block did not have a notable advantage over the sham block in terms of pain relief at rest, as assessed by the numeric rating scale score, 6 hour after total hip arthroplasty (iliopsoas plane block: median, 4.0; IQR, 2.0-5.8; sham: median, 5.5; IQR, 2.3-6.8; median difference, -1.0; 95% CI -2.0 to 0.0; p≥0.999). Linear mixed model analysis showed no differences in pain scores, opioid consumption, quadriceps strength, or quality of recovery between the groups. CONCLUSIONS: Iliopsoas plane block did not improve postoperative analgesia following total hip arthroplasty under general anesthesia with a multimodal analgesic regimen. The blockade of sensory femoral branches supplying the anterior hip capsule using iliopsoas plane block may not yield additional benefits concerning patient outcomes in the aforementioned clinical context. TRIAL REGISTRATION NUMBER: NCT05212038, https://clinicaltrials.gov/ct2/show/NCT05212038.

Comparison of the incidence of intravascular injection using the Tuohy and Quincke needles during ultrasound-guided caudal epidural block: a prospective randomized controlled study.

INTRODUCTION: Intravascular injection of a local anesthetic can lead to life-threatening complications, such as deficits in neurological function after caudal epidural block. This study aimed to determine whether the intravascular injection rate of the Tuohy needle is lower than that of the Quincke needle during an ultrasound-guided caudal block. METHODS: Two-hundred and thirty patients were randomized into the Quincke (n=115) and the Tuohy (n=115) needle groups. The randomly selected needle was introduced at a 45° angle until it penetrated the sacrococcygeal ligament under ultrasound guidance, and intravenous injections were analyzed using contrast-dyed digital subtraction angiography. The relationship between the incidence of intravascular injection and independent variables, including needle type, patient demographics, history of lumbosacral surgery, use of anticoagulants, anatomic variables of the sacrum, presence of bony contact during the procedure, and the number of needle repositioning under ultrasound guidance, were examined. RESULTS: Intravascular uptake of contrast medium was surveyed in 25/230 (10.9%) caudal blocks using digital subtraction angiography (DSA). The incidence of intravascular uptake was 13.9% (16/115) using the Quincke needle and 7.8% (9/115) using the Tuohy needle (p=0.14). Although the needle tip type was not associated with the rate of intravascular injection, the occurrence of bony contact during the procedure demonstrated a relationship with the intravenous injection (p<0.01). CONCLUSIONS: The overall incidence of inadvertent intravascular injections during ultrasound-guided caudal block confirmed using DSA was 10.9%. Tuohy needles did not reduce intravascular injection rates during the ultrasound-guided caudal block. TRIAL REGISTRATION NUMBER: NCT05504590.

Reliable synaptic plasticity of InGaZnO transistor with TiO2interlayer.

We demonstrate an InGaZnO (IGZO)-based synaptic transistor with a TiO2buffer layer. The structure of the synaptic transistor with TiO2inserted between the Ti metal electrode and an IGZO semiconductor channel O2trapping layer produces a large hysteresis window, which is crucial for achieving synaptic functionality. The Ti/TiO2/IGZO synaptic transistor exhibits reliable synaptic plasticity features such as excitatory post-synaptic current, paired-pulse facilitation, and potentiation and depression, originating from the reversible charge trapping and detrapping in the TiO2layer. Finally, the pattern recognition accuracy of Modified National Institute of Standards and Technology handwritten digit images was modeled using CrossSim simulation software. The simulation results present a high image recognition accuracy of ∼89%. Therefore, this simple approach using an oxide buffer layer can aid the implementation of high-performance synaptic devices for neuromorphic computing systems.

Surface-Modified Pore-Filled Anion-Exchange Membranes for Efficient Energy Harvesting via Reverse Electrodialysis.

In this study, novel pore-filled anion-exchange membranes (PFAEMs) modified with polypyrrole (PPy) and reduced graphene oxide (rGO) were developed to improve the energy harvesting performance of reverse electrodialysis (RED). The surface-modified PFAEMs were fabricated by varying the contents of PPy and rGO through simple spin coating and chemical/thermal treatments. It was confirmed that the PPy and PPy/rGO layers introduced on the membrane surface did not significantly increase the electrical resistance of the membrane and could effectively control surface characteristics, such as structural tightness, hydrophilicity, and electrostatic repulsion. The PPy/rGO-modified PFAEM showed excellent monovalent ion selectivity, more than four times higher than that of the commercial membrane (AMX, Astom Corp., Tokyo, Japan). This means that the PPy/rGO layer can effectively reduce the permeation of multivalent ions with a high charge intensity and a relatively large hydration radius compared to monovalent ions. The results of evaluating the performance of the surface-modified PFAEMs by applying them to a RED cell revealed that the decrease in potential difference occurring in the membrane was reduced by effectively suppressing the uphill transport of multivalent ions. Consequently, the PPy/rGO-modified membrane exhibited a 5.43% higher power density than the AMX membrane.

Comparison of injectate spread and nerve coverage between single-injection intertransverse process block and paravertebral block at the T2 level: a cadaveric study.

BACKGROUND: We compared the spread of an injectate into the thoracic sympathetic chain resulting from a single-injection intertransverse process (ITP) block with that of a single-injection PV block at the T2 level. METHODS: Sixteen soft-embalmed cadavers were used. The right hemithorax was randomly allocated to receive either an ultrasound-guided single-injection ITP block or ultrasound-guided single-injection PV block at the T2 vertebral level, with the opposite block administered to the other side. Approximately 10 mL of latex dye solution was injected into each hemithorax using a random allocation technique. The presence of dye at the nerve root in the sympathetic chain and intercostal nerves at the injection and additional levels was examined by dissection. RESULTS: The injectate spread into the T2 sympathetic ganglion on both ITP (11/16, 68.8%) and PV (16/16, 100%) blocks. The ITP block demonstrated greater uniformity of dye staining in both the dorsal rami and dorsal root ganglion, which contrasts with the less consistent staining outcomes of the PV block in these regions. CONCLUSIONS: At the T2 level, we observed a lower efficacy of the ITP block for analgesic coverage of the sympathetic nerve. This suggested a potential preference by clinicians for the application of the T2 PV block over the ITP block, specifically for the management of sympathetically maintained pain in the upper extremities. In addition, our findings may hint at the potential advantages of the ITP block in specific clinical contexts where targeted nerve involvement, such as the medial branch block or dorsal root ganglion block, is sought.

A novel technique of handling the blade for videolaryngoscopy intubation in patients with a semi-rigid neck collar: a prospective randomized controlled trial.

BACKGROUND: Semi-rigid neck collars to protect the cervical spine can limit the extent of neck movement and mouth opening; this may further complicate orotracheal intubation. We aimed to compare intubation environments obtained with videolaryngoscopy using the technique of gliding a blade under the epiglottis and that obtained using the conventional Macintosh blade technique of blade tip placement on the vallecula. METHODS: This prospective randomized study included patients aged ≥ 20 years with American Society of Anesthesiologists physical status I-III scheduled for cervical spine surgery between October 2020 and August 2021. Patients were divided into two groups according to the placement of the blade of the McGrathTM videolaryngoscope: the gliding and conventional groups. The percentage of glottic opening (POGO) score was the primary endpoint. We also recorded the time to obtain the optimal laryngoscopic view, intubation duration, and ease and satisfaction of the researcher performing intubation. RESULTS: Among 176 patients, the POGO scores were significantly higher in the gliding group than in the conventional group (88.9 ± 14.7 vs. 63.8 ± 27.4, P < 0.001). The time to achieve the optimal glottic view for intubation and duration of intubation were also shorter, and ease and satisfaction in performing intubation were better in the gliding group than in the conventional group. CONCLUSION: Our findings demonstrated a superior glottic view and more favorable intubation environments when the blade tip was placed under the epiglottis than using the conventional Macintosh technique in patients with immobilized cervical spine.

Anatomical and Radiological Assessments of Injectate Spread Stratified by the Volume of the Pericapsular Nerve Group Block.

BACKGROUND: The pericapsular nerve group (PENG) block was recently suggested as a regional technique for managing acute pain after hip surgery. However, few anatomical studies have confirmed the spread of injectate during the PENG block. This cadaver study aimed to analyze injectate spread to the target nerves during single-injection ultrasound-guided PENG block. METHODS: Ultrasound-guided PENG block with 3 different injectate volumes (10, 20, or 30 mL) was performed in 18 cadavers. Injectate spread by the volume was first evaluated on computed tomography, followed by cadaver dissection. The spread of the dye over the pelvis and lower limb was evaluated. RESULTS: The articular branches of the femoral nerve were stained nearly sufficiently with 20- and 30-mL specimens. The femoral nerve itself was stained simultaneously in six of 12 (50%) 20-mL specimens and 12 of 12 (100%) 30-mL specimens. The accessory obturator nerve was observed only in three (9%) of 36 specimens. The articular branches of the obturator nerve were rarely affected, regardless of injectate volume (1/12, 10 mL specimens; 2/12, 20 mL specimens; 1/12, 30 mL specimens; P > .999). Rather, the obturator nerve was affected. However, the obturator nerve was not stained consistently even with 30 mL of injectate (50%). CONCLUSIONS: After combining the dissection and radiological findings, the single-injection ultrasound-guided PENG blocks with volumes of 10, 20, and 30 mL do not support motor sparing or selective anterior hip capsule innervation in a clinical setting. If early rehabilitation is needed, high-volume PENG block might not be the ideal option, and persisting pain after PENG block might be attributed in part to the lack of obturator nerve articular branches blockade.

Comparison of the effects of inhalational and total intravenous anesthesia on quality of recovery in patients undergoing endoscopic transsphenoidal pituitary surgery: a randomized controlled trial.

Background: Endoscopic transsphenoidal pituitary surgery has shown promising results. However, fast and high-quality recovery after this procedure remains a challenge for neuroanesthesiologists. This study aimed to compare the quality of recovery after transsphenoidal pituitary surgery between patients who received inhalational anesthesia with sevoflurane and patients who received propofol-based total intravenous anesthesia (TIVA). Methods: Eighty-two patients undergoing transsphenoidal pituitary surgery were randomized to receive either sevoflurane inhalation with manual infusion of remifentanil (sevoflurane group) or effect-site target-controlled infusion of propofol and remifentanil (TIVA group). The primary outcome was the 40-item Quality of Recovery (QoR-40) score on postoperative day 1. The QoR-40 questionnaire was completed by patients the day before surgery and on postoperative days 1 and 2. Emergence agitation and recovery characteristics were also assessed. Results: There were no significant differences between the groups in the global QoR-40 scores on both postoperative days 1 and 2 (difference -8.7, 95% CI -18.0 to 0.7, and P = 0.204; -3.6, 95% CI -13.0 to 5.8, and P > 0.999, respectively). The time to verbal response and time to extubation were significantly shorter in the sevoflurane group than in the TIVA group (P < 0.001 and P < 0.001, respectively). However, the incidence of emergence agitation was lower in the TIVA group than in the sevoflurane group (P < 0.001). Conclusions: Both inhalational anesthesia with sevoflurane and propofol-based TIVA were appropriate anesthetic techniques for patients undergoing endoscopic transsphenoidal pituitary surgery in terms of the quality of recovery up to 2 days postoperatively. Rapid emergence was observed in the sevoflurane group, while smooth emergence was observed in the TIVA group.

Effect of Previous Caudal Block to Predict Successful Outcome after Adhesiolysis using a Steerable Catheter in Lumbar Failed Back Surgery Syndrome: A Retrospective Study.

Adhesiolysis is minimally invasive and commonly used for pain associated with adhesion after lumbar spine surgery. Caudal epidural block may be used for radiating pain due to failed back surgery syndrome. We evaluated the predictive value of response to caudal block performed prior to adhesiolysis in failed back surgery syndrome. Between January 1, 2013 and June 30, 2020, 150 patients with failed back surgery syndrome were treated with adhesiolysis using a steerable catheter at the pain clinic of a tertiary hospital after failed conservative treatment (including caudal block). Patient demographics, pain duration, and lumbar magnetic resonance imaging findings were examined. Response to previous caudal block was determined as a binary result (yes or no). Patients were followed up 3 months after adhesiolysis. Successful outcome was defined as a ≥2-point reduction in the numeric rating scale scores for radicular pain 3 months after adhesiolysis, evident in 81/150 (46%) patients. Multivariable logistic regression analysis revealed that caudal block response was an independent predictor of successful adhesiolysis (odds ratio = 4.403; p = 0.015). Response to prior caudal block is a positive predictor of successful adhesiolysis.

Comparison of pharmacologic therapies alone versus operative techniques in combination with pharmacologic therapies for postoperative analgesia in patients undergoing laparoscopic cholecystectomy: A randomized controlled trial.

BACKGROUND: Laparoscopic cholecystectomy (LC) causes moderate pain. Various operative analgesic techniques and pharmacologic treatments can reduce postoperative pain. This single-center, single-surgeon randomized controlled study aimed to assess the efficacy of combined operative analgesic techniques and pharmacologic analgesia in decreasing pain in patients undergoing LC. MATERIALS AND METHODS: Fifty-nine patients scheduled for LC were assigned into two groups. In the pharmacologic analgesia (P) group (n = 29), patients were treated with pharmacologic intervention, including preoperative celecoxib (200 mg), intraoperative acetaminophen (1 g), and dexamethasone (8 mg). In the operative analgesic treatments with pharmacologic analgesia (OP) group (n = 30), patients were treated with both operative analgesic techniques and pharmacologic analgesia, including low-pressure pneumoperitoneum, intraperitoneal normal saline irrigation, and aspiration of intraperitoneal carbon dioxide. The area under the curve (AUC) of pain score for postoperative 24 h was assessed at 0, 2, 6, and 24 h post-operation. The analgesic requirements and sleep quality at postoperative day 1 were assessed. RESULTS: The AUC/24 h of pain scores at rest and on cough were lower in the OP group (p < 0.001 and p = 0.001, respectively). The pain scores at rest were lower in the OP group at postoperative 2, 6, and 24 h (p = 0.001, p = 0.001, and p = 0.048, respectively). The pain scores on cough were lower in the OP group at postoperative 2 and 6 h (p = 0.004 and p = 0.008, respectively). Analgesic requirements were comparable. The sleep quality score at postoperative day 1 was higher in the OP group (56 ± 18 vs. 67 ± 15, absolute difference, 10; 95% confidence interval, 2 to 19; p = 0.017). CONCLUSIONS: Combined operative analgesic therapies and pharmacologic analgesia compared to pharmacologic analgesia alone decreased pain scores and increased sleep quality in patients undergoing LC.

Pericapsular Nerve Group (PENG) Block versus Supra-Inguinal Fascia Iliaca Compartment Block for Total Hip Arthroplasty: A Randomized Clinical Trial.

This study compared the effects of the pericapsular nerve group (PENG) block and supra-inguinal fascia iliaca compartment block (FICB) on postoperative analgesia and quadriceps strength following total hip arthroplasty under general anesthesia. A total of 58 patients were randomized to receive either PENG block (PENG group) or supra-inguinal FICB (FICB group) following anesthetic induction. The primary outcomes were the postoperative pain scores. Patients were randomized to receive either PENG block or supra-inguinal FICB following anesthetic induction. Pain scores at rest and with movement were assessed preoperatively, at the postanesthesia care unit (only at rest), and at 6, 24, 36, and 48 h postoperatively. Opioid consumption was also assessed for 48 h postoperatively. Quadriceps strength measurements were performed preoperatively, at 6, 24, and 36 h postoperatively. In total, 54 patients completed the study: 27 in the PENG group and 27 in the FICB group. Despite lower pain scores at rest in the PENG group at postoperative 6 and 24 h, there were no significant differences in the pain scores at rest and during movement between the two groups during postoperative 48 h in the linear mixed model analysis (p = 0.079 and p = 0.323, respectively). Cumulative opioid consumption up to postoperative 48 h was also similar in the two groups (p = 0.265). The changes in quadriceps strength measurements in the operative leg and the nonoperative leg were not significantly different between the groups (p = 0.513 and p = 0.523, respectively). The PENG block may have similar analgesic efficacy to the supra-inguinal FICB. No difference was detected in the quadriceps strength between the patients receiving these two blocks.

Thin-Reinforced Anion-Exchange Membranes with High Ionic Contents for Electrochemical Energy Conversion Processes.

Ion-exchange membranes (IEMs) are a core component that greatly affects the performance of electrochemical energy conversion processes such as reverse electrodialysis (RED) and all-vanadium redox flow battery (VRFB). The IEMs used in electrochemical energy conversion processes require low mass transfer resistance, high permselectivity, excellent durability, and also need to be inexpensive to manufacture. Therefore, in this study, thin-reinforced anion-exchange membranes with excellent physical and chemical stabilities were developed by filling a polyethylene porous substrate with functional monomers, and through in situ polymerization and post-treatments. In particular, the thin-reinforced membranes were made to have a high ion-exchange capacity and a limited degree of swelling at the same time through a double cross-linking reaction. The prepared membranes were shown to possess both strong tensile strength (>120 MPa) and low electrical resistance (<1 Ohm cm2). As a result of applying them to RED and VRFB, the performances were shown to be superior to those of the commercial membrane (AMX, Astom Corp., Japan) in the optimal composition. In addition, the prepared membranes were found to have high oxidation stability, enough for practical applications.

The Comparison of Fluoroscopy-Guided Epidural Anesthesia with Conscious Sedation and General Anesthesia for Endoscopic Lumbar Decompression Surgery: A Retrospective Analysis.

BACKGROUND: With advances and refinements in endoscopic lumbar spine surgery showing effective and satisfactory results, the need for simple yet effective anesthetic techniques for minimally invasive endoscopic spine surgery has increased. The aim of this study was to compare feasibility and postoperative outcomes of fluoroscopy-guided epidural anesthesia with general anesthesia in patients undergoing endoscopic lumbar decompression surgery (≤3 levels). METHODS: Patients who underwent 1-3 levels of endoscopic lumbar decompression surgery under either fluoroscopy-guided epidural or general anesthesia between January 2019 and October 2020 were retrospectively reviewed. Postoperative pain intensity and use of rescue analgesics for up to 48 hours were compared between the epidural and general anesthesia groups. Intraoperative anesthetic data and postoperative recovery profiles were also analyzed. RESULTS: Postoperative pain scores were significantly lower in the epidural anesthesia group compared with the general anesthesia group at 10 minutes after recovery room admission (2.1 ± 1.8 vs. 5.7 ± 1.9, P < 0.001), 24 hours postoperatively (3.3 ± 1.0 vs. 5.4 ± 1.8, P < 0.001), and 48 hours postoperatively (3.2 ± 0.6 vs. 4.4 ± 1.4, P < 0.001). The proportion of patients requiring rescue analgesics in the recovery room was significantly lower in the epidural anesthesia group (1.9% vs. 20.5%, P = 0.027). The median 15-item Quality of Recovery score on postoperative day 1 was significantly higher in the epidural anesthesia group (118.0 [113.5-123.0] vs. 82.0 [73.5-111.5], P < 0.001). Occurrence of nausea, vomiting, and voiding difficulty up to 48 hours postoperatively did not differ between groups. CONCLUSIONS: Compared with general anesthesia, epidural anesthesia provided better analgesia and recovery characteristics during the early postoperative period in endoscopic lumbar decompression surgery.

Ability of Carotid Corrected Flow Time to Predict Fluid Responsiveness in Patients Mechanically Ventilated Using Low Tidal Volume after Surgery.

Predicting fluid responsiveness in patients under mechanical ventilation with low tidal volume (VT) is challenging. This study evaluated the ability of carotid corrected flow time (FTc) assessed by ultrasound for predicting the fluid responsiveness during low VT ventilation. Patients under postoperative mechanical ventilation and clinically diagnosed with hypovolemia were enrolled. Carotid FTc and pulse pressure variation (PPV) were measured at VT of 6 and 10 mL/kg predicted body weight (PBW). FTc was calculated using both Bazett's (FTcB) and Wodey's (FTcW) formulas. Fluid responsiveness was defined as a ≥15% increase in the stroke volume index assessed by FloTrac/Vigileo monitor after administration of 8 mL/kg of balanced crystalloid. Among 36 patients, 16 (44.4%) were fluid responders. The areas under the receiver operating characteristic curves (AUROCs) for the FTcB at VT of 6 and 10 mL/kg PBW were 0.897 (95% confidence interval [95% CI]: 0.750-0.973) and 0.895 (95% CI: 0.748-0.972), respectively. The AUROCs for the FTcW at VT of 6 and 10 mL/kg PBW were 0.875 (95% CI: 0.722-0.961) and 0.891 (95% CI: 0.744-0.970), respectively. However, PPV at VT of 6 mL/kg PBW (AUROC: 0.714, 95% CI: 0.539-0.852) showed significantly lower accuracy than that of PPV at VT of 10 mL/kg PBW (AUROC: 0.867, 95% CI: 0.712-0.957; p = 0.034). Carotid FTc can predict fluid responsiveness better than PPV during low VT ventilation. However, further studies using automated continuous monitoring system are needed before its clinical use.

Anterior neck soft tissue measurements on computed tomography to predict difficult laryngoscopy: a retrospective study.

Predicting difficult laryngoscopy is an essential component of the airway management. We aimed to evaluate the use of anterior neck soft tissue measurements on computed tomography for predicting difficult laryngoscopy and to present a clear measurement protocol. In this retrospective study, 281 adult patients whose tracheas were intubated using a direct laryngoscope for thyroidectomy were enrolled. On computed tomography, the distances from the midpoint of the thyrohyoid membrane to the closest concave point of the vallecular (membrane-to-vallecula distance; dMV), and to the most distant point of the epiglottis (membrane-to-epiglottis distance; dME) were measured, respectively. The extended distances straight to the skin anterior from the dMV and dME were called the skin-to-vallecula distance (dSV) and skin-to-epiglottis distance (dSE), respectively. Difficult laryngoscopy was defined by a Cormack-Lehane grade of > 2. Difficult laryngoscopy occurred in 40 (14%) cases. Among four indices, the dMV showed the highest prediction ability for difficult laryngoscopy with an area under the receiver operating characteristic curve of 0.884 (95% confidence interval 0.841-0.919, P < 0.001). The optimal dMV cut-off value for predicting difficult laryngoscopy was 2.33 cm (sensitivity 75.0%; specificity 93.8%). The current study provides novel evidence that increased dMV is a potential predictive indicator of difficult laryngoscopy.

A novel electromagnetic guidance ultrasound system on radial artery cannulation: a prospective randomized controlled trial.

BACKGROUND: Radial artery cannulation can cause complications such as haematoma formation or thrombosis due to its small diameter. Recently, a novel ultrasound device equipped with an electromagnetic guidance system was introduced, showing the path and alignment of the needle during the procedure. The aim of this study was to investigate the effects of this novel system on both success and complication rates during radial artery cannulation under ultrasound guidance. METHODS: In this randomized controlled trial, 76 adults scheduled for neurosurgery requiring radial artery cannulation were recruited. In group E (n = 38), radial artery cannulation was performed using the electromagnetic guidance ultrasound system, whereas in group C (n = 38), the procedure was performed using conventional ultrasound guidance. The success rates of cannulation on the first attempt, cannulation times, number of attempts, and incidence of complications were compared between the two groups. RESULTS: There was a significant difference in the success rates on the first attempt between the two groups (group C = 78.9% vs. group E = 94.7%, P = 0.042). Incidences of posterior wall puncture and haematoma formation (group C = 8 vs. group E = 1; P = 0.028) were significantly lower in group E than in group C. The median cannulation time for successful attempts was comparable between groups. CONCLUSIONS: Use of the novel electromagnetic guidance system resulted in a better success rate on the first attempt and a lower incidence of complications during radial artery cannulation. TRIAL REGISTRATION: This study was registered at http://cris.nih.go.kr (registration number: KCT0002476 ).

Predictability of preoperative carotid artery-corrected flow time for hypotension after spinal anaesthesia in patients undergoing caesarean section: A prospective observational study.

BACKGROUND: Spinal anaesthesia-induced hypotension is frequently reported in patients undergoing caesarean section. Mechanistically, sympathetic blockade reduces the systemic vascular resistance and the left ventricular preload, causing hypotension, which is augmented by aortocaval compression. The corrected blood flow time (FTc) is affected by the preload and is inversely related to the afterload. OBJECTIVE: We hypothesised that the preanaesthetic carotid artery FTc could predict hypotension after induction in patients undergoing a caesarean section with spinal anaesthesia. DESIGN: A prospective observational study. SETTING: A tertiary referral centre in South Korea from September 2018 to November 2019. PARTICIPANTS: Thirty-eight parturients scheduled for elective caesarean section under spinal anaesthesia. INTERVENTIONS: Using carotid ultrasonography, FTc was measured twice prior to inducing spinal anaesthesia. FTc was calculated using both Bazett's (B) and Wodey's (W) formulae. Hypotension was defined as an SBP decrease to less than 80 mmHg, or less than 75% of baseline, or if symptoms consistent with hypotension occurred from the time of injection of the spinal anaesthetic until delivery. MAIN OUTCOME MEASURES: The primary endpoint was to determine the predictive value of preanaesthetic FTc for postspinal hypotension during caesarean delivery. RESULTS: Among the 35 patients who completed this study, hypotension occurred in 21 (60%). The areas under the receiver-operating characteristic curves for FTc (B) and FTc (W) were 0.905 [95% confidence interval (CI), 0.757 to 0.978, P < 0.001] and 0.922 (95% CI, 0.779 to 0.985, P < 0.001), respectively. The optimal cut-off values for predicting hypotension were 346.4 and 326.9 ms, respectively. The grey zone for FTc (B) and FTc (W) included 40 and 14% of the patients, respectively. CONCLUSION: Preanaesthetic carotid artery FTc was a reliable indicator of postspinal hypotension in parturients. Considering the grey zone, Wodey's formula is better than Bazett's formula. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03631329.

Bipolar Membranes to Promote Formation of Tight Ice-Like Water for Efficient and Sustainable Water Splitting.

Bipolar membranes (BPMs) have recently received much attention for their potential to improve the water dissociation reaction (WDR) at their junction by utilizing catalysts. Herein, composite catalysts (Fe2 O3 @GO) comprising hematite nanoparticles (α-Fe2 O3 ) grown on 2D graphene oxide (GO) nanosheets are reported, which show unprecedentedly high water dissociation performance in the BPM. Furthermore, new catalytic roles in facilitating WDR at the catalyst-water interface are mechanistically elucidated. It is demonstrated that the partially dissociated bound water, formed by the strongly Lewis-acidic Fe atoms of the Fe2 O3 @GO catalyst, helps the "ice-like water" to become tighter, consequently resulting in weaker intramolecular OH bonds, which reduces activation barriers and thus significantly improves the WDR rate. Notably, Fe2 O3 @GO-incorporated BPM shows an extremely low water dissociation potential (0.89 V), compared to commercially available BPM (BP-1E, 1.13 V) at 100 mA cm-2 , and it is quite close to the theoretical potential required for WDR (0.83 V). This performance reduces the required electrical energy consumption for water splitting by ≈40%, as compared to monopolar (Nafion 212 and Selemion AMV) membranes. These results can provide a new approach for the development of water dissociation catalysts and BPMs for realizing highly efficient water splitting systems.