Investigation of Appropriate Scaling of Networks and Images for Convolutional Neural Network-Based Nerve Detection in Ultrasound-Guided Nerve Blocks.

Ultrasound imaging is an essential tool in anesthesiology, particularly for ultrasound-guided peripheral nerve blocks (US-PNBs). However, challenges such as speckle noise, acoustic shadows, and variability in nerve appearance complicate the accurate localization of nerve tissues. To address this issue, this study introduces a deep convolutional neural network (DCNN), specifically Scaled-YOLOv4, and investigates an appropriate network model and input image scaling for nerve detection on ultrasound images. Utilizing two datasets, a public dataset and an original dataset, we evaluated the effects of model scale and input image size on detection performance. Our findings reveal that smaller input images and larger model scales significantly improve detection accuracy. The optimal configuration of model size and input image size not only achieved high detection accuracy but also demonstrated real-time processing capabilities.

Effects of anesthetics on expression of dopamine and acetylcholine receptors in the rat brain in vivo.

Dopamine D2 and acetylcholine M1 receptors might be related to post-operative cognitive dysfunction. The aim of the present study is to investigate whether several anesthetics which are used for general anesthesia and/or sedation, affect expression of dopamine D2 and acetylcholine M1 receptors in the rat brain. Thirty-six male rats aged 5-9 weeks old were divided into six groups (n = 6 in each group); five groups for anesthetics and one for control. The five groups were anesthetized with either dexmedetomidine 0.4 µg/kg/min, propofol 50 mg/kg/h, midazolam 25 mg/kg/h, sevoflurane 3.3%, or nitrous oxide 75% for 4 h. Then, the rats were decapitated, and the cerebral cortex, hippocampus, corpus striatum, brain stem, and cerebellum were collected from all rats. Then, real-time polymerase chain reaction was performed to examine the expression of Drd2 (cord dopamine D2 receptor) and Chrm1 (cord acetylcholine M1 receptor). There were no significant differences among the groups regarding Drd2 and Chrm1 mRNA expression of each region of the brain. Postsynaptic changes of dopamine D2 and acetylcholine M1 receptors due to administration of dexmedetomidine, propofol, midazolam, sevoflurane, and nitrous oxide are unlikely to occur at the doses of each anesthetic used in the present study.

Opening of Intermediate Conductance Ca2+-Activated K+ Channels in C2C12 Skeletal Muscle Cells Increases the Myotube Diameter via the Akt/Mammalian Target of Rapamycin Pathway.

The activation of potassium channels and the ensuing hyperpolarization in skeletal myoblasts are essential for myogenic differentiation. However, the effects of K+ channel opening in myoblasts on skeletal muscle mass are unclear. Our previous study revealed that pharmacological activation of intermediate conductance Ca2+-activated K+ channels (IKCa channels) increases myotube formation. In this study, we investigated the effects of 5,6-dichloro-1-ethyl-1,3-dihydro-2H-benzimidazol-2-one (DCEBIO), a Ca2+-activated K+ channel opener, on the mass of skeletal muscle. Application of DCEBIO to C2C12 cells during myogenesis increased the diameter of C2C12 myotubes in a concentration-dependent manner. This DCEBIO-induced hypertrophy was abolished by gene silencing of IKCa channels. However, it was resistant to 1 µM but sensitive to 10 µM TRAM-34, a specific IKCa channel blocker. Furthermore, DCEBIO reduced the mitochondrial membrane potential by opening IKCa channels. Therefore, DCEBIO should increase myotube mass by opening of IKCa channels distributed in mitochondria. Pharmacological studies revealed that mitochondrial reactive oxygen species (mitoROS), Akt, and mammalian target of rapamycin (mTOR) are involved in DCEBIO-induced myotube hypertrophy. An additional study demonstrated that DCEBIO-induced muscle hypertrophic effects are only observed when applied in the early stage of myogenic differentiation. In an in vitro myotube inflammatory atrophy experiment, DCEBIO attenuated the reduction of myotube diameter induced by endotoxin. Thus, we concluded that DCEBIO increases muscle mass by activating the IKCa channel/mitoROS/Akt/mTOR pathway. Our study suggests the potential of DCEBIO in the treatment of muscle wasting diseases. SIGNIFICANCE STATEMENT: Our study shows that 5,6-dichloro-1-ethyl-1,3-dihydro-2H-benzimidazol-2-one (DCEBIO), a small molecule opener of Ca2+-activated K+ channel, increased muscle diameter via the mitochondrial reactive oxygen species/Akt/mammalian target of rapamycin pathway. And DCEBIO overwhelms C2C12 myotube atrophy induced by endotoxin challenge. Our report should inform novel role of K+ channel in muscle development and novel usage of K+ channel opener such as for the treatment of muscle wasting diseases.

Increase in Blood Pressure by Local Injection of Ketamine into the Amygdala in Rats.

To confirm that an increase in blood pressure induced by ketamine is mediated through the central nervous system, we examined the effect of ketamine, applied directly to the amygdala, on blood pressure. Six male Sprague-Dawley rats were used in the study. Under head-restrained and unanesthetized condition, 0.2 µL (5 mg/mL) of ketamine was injected in and around the amygdala at a flow rate of 0.2 µL/min through a glass pipette, and the blood pressure was recorded while monitoring the state of the animals by electroencephalogram and electromyogram. After ketamine injection, the injection site was marked by Pontamine Sky Blue infusion. Blood pressure was increased by ketamine injection into the basolateral and central nuclei of the amygdala, endopiriform nucleus and piriform cortex. In a total of 11 responses, an increase in blood pressure started with a mean latency of 193.5 ± 43.0 s, reached its peak 180.2 ± 23.3 s after the response onset, then gradually returned to the baseline with mean duration of 706.7 ± 113.5 s. The mean fluctuation was 17.1 ± 2.5 mmHg. We revealed that blood pressure fluctuations induced by ketamine are associated with the amygdala. Elucidation of the mechanism of ketamine-induced blood pressure increase will lead to understanding of the mechanism of side effects of ketamine, and will contribute to its appropriate use.

Adjustment of oxygen reserve index (ORi™) to avoid excessive hyperoxia during general anesthesia.

The Oxygen Reserve Index (ORi™) is a non-invasive variable that reflects oxygenation continuously. The aims of this study were to examine the relationship between arterial partial pressure of oxygen (PaO2) and ORi during general anesthesia, and to investigate the usefulness of ORi as an indicator to avoid hyperoxia. Twenty adult patients who were scheduled for surgery under general anesthesia with arterial catheterization were enrolled. After induction of general anesthesia, inspired oxygen concentration (FiO2) was set to 0.33, and arterial blood gas analysis was performed. The PaO2 and ORi at the time of blood collection were recorded. After that, FiO2 was changed to achieve an ORi around 0.5, 0.2, and 0, followed by arterial blood gas analysis. The relationship between ORi and PaO2 was then investigated using the data obtained. Eighty datasets from the 20 patients were analyzed. When PaO2 was less than 240 mmHg (n = 69), linear regression analysis showed a relatively strong positive correlation (r2 = 0.706). The cut-off ORi value obtained from the receiver operating characteristic curve to detect PaO2 ≥ 150 mmHg was 0.21 (sensitivity 0.950, specificity 0.755). Four-quadrant plot analysis showed that the ORi trending of PaO2 was good (concordance rate was 100.0%). Hyperoxemia can be detected by observing ORi of patients under general anesthesia, and thus unnecessary administration of high concentration oxygen can possibly be avoided.

The effectiveness of the intramuscular quadratus lumborum block in postoperative analgesia after cesarean section with vertical incision: a randomized, double-blinded placebo-controlled study.

PURPOSE: Quadratus lumborum block (QLB) has recently been used for postoperative analgesia after abdominal surgery. Although there are several approaches to QLB, the effectiveness of intramuscular QLB (QLBi) remains controversial. The aim of the present study was to examine the effectiveness of QLBi for postoperative analgesia after cesarean section with a vertical midline incision. METHODS: In this single-center, randomized, double-blinded placebo-controlled study, 36 women who were scheduled for elective cesarean section were randomly divided into a QLBi group (n = 18) and a placebo group (n = 18). In both groups, spinal anesthesia was performed with 10-11 mg hyperbaric bupivacaine and 15 µg fentanyl. After the surgery, in the QLBi group, 0.4 mL/kg of 0.25% ropivacaine was injected into the bilateral quadratus lumborum muscle under ultrasound guidance (the total volume was 0.8 mL/kg). In the placebo group, instead of ropivacaine, the subjects were injected with the same amount of normal saline. The primary outcome measure was elapsed time to first analgesic use from the QLBi block after cesarean section. RESULTS: The data from all 36 patients were analyzed. There were no significant differences between the QLBi and placebo groups regarding elapsed time to first postoperative analgesic use [mean 230 (standard deviation 103) vs 194 (89) min; 95% confidence interval - 101 to 30; p = 0.27]. CONCLUSIONS: QLBi with the concentration and amount of local anesthetic used in the present study was clinically slightly effective, and the effect was limited for postoperative analgesia after cesarean section.

The predictive performance of propofol target-controlled infusion during robotic-assisted laparoscopic prostatectomy with CO2 pneumoperitoneum in the head-down position.

PURPOSE: Propofol clearance can be reduced when cardiac output (CO) is decreased. This clearance reduction may alter the pharmacokinetics of propofol and worsen the predictive performance of target-controlled infusion (TCI) of propofol. The head-down position (HDP) and CO2 pneumoperitoneum, which are required for robotic-assisted laparoscopic prostatectomy (RALP), may cause changes in CO. We investigated the predictive performance of propofol TCI during CO2 pneumoperitoneum in patients who underwent RALP in the HDP. METHODS: Fifteen male patients received propofol TCI using the Diprifusor model. Propofol concentrations were measured at seven time points: (T1) 15 min after anesthesia induction; (T2) before the insufflation; (T3, T4, and T5) 15, 60, and 90 min, respectively, after insufflation in the HDP; (T6) before the release of pneumoperitoneum in the HDP; and (T7) 15 min after the release of pneumoperitoneum in the supine position. Cardiac index (CI) was assessed using an arterial pulse contour CO monitor. The predictive performance of propofol TCI was evaluated by calculating the performance errors (PE) in propofol concentrations for each data point. The relationship between CI and PE was examined. Median PE (MDPE) and median absolute PE (MDAPE) were calculated as measures of bias and accuracy, respectively. RESULTS: A total of 104 blood samples were analyzed. There was significantly negative correlation between CI and PE. The predictive performance of propofol TCI during pneumoperitoneum in the HDP was acceptable (MDPE = - 1.5% and MDAPE = 18.8%). CONCLUSION: The predictive performance of propofol TCI during RALP with CO2 pneumoperitoneum in the HDP was acceptable.

Computerized Hammer Sounding Interpretation for Concrete Assessment with Online Machine Learning.

Developing efficient Artificial Intelligence (AI)-enabled systems to substitute the human role in non-destructive testing is an emerging topic of considerable interest. In this study, we propose a novel hammering response analysis system using online machine learning, which aims at achieving near-human performance in assessment of concrete structures. Current computerized hammer sounding systems commonly employ lab-scale data to validate the models. In practice, however, the response signal patterns can be far more complicated due to varying geometric shapes and materials of structures. To deal with a large variety of unseen data, we propose a sequential treatment for response characterization. More specifically, the proposed system can adaptively update itself to approach human performance in hammering sounding data interpretation. To this end, a two-stage framework has been introduced, including feature extraction and the model updating scheme. Various state-of-the-art online learning algorithms have been reviewed and evaluated for the task. To conduct experimental validation, we collected 10,940 response instances from multiple inspection sites; each sample was annotated by human experts with healthy/defective condition labels. The results demonstrated that the proposed scheme achieved favorable assessment accuracy with high efficiency and low computation load.

Usefulness of oxygen reserve index (ORi™), a new parameter of oxygenation reserve potential, for rapid sequence induction of general anesthesia.

The oxygen reserve index (ORi™) is a new parameter for monitoring oxygen reserve noninvasively. The aim of this study was to examine the usefulness of ORi for rapid sequence induction (RSI). Twenty adult patients who were scheduled for surgical procedures under general anesthesia were enrolled. After attaching a sensor capable of measuring ORi, oxygen (6 L/min) and fentanyl (2 µg/kg) were administered. After 3 min, propofol 2 mg/kg and rocuronium 1 mg/kg were administered without ventilation. Regardless of changes in ORi, tracheal intubation was performed either 2 min after administration of propofol or when percutaneous oxygen saturation (SpO2) reached 98%. Ventilation was then provided with oxygen at 6 L/min, and trends in ORi and SpO2 during RSI were observed. Data from 16 of the 20 patients were analyzed. Before oxygen administration, the median SpO2 was 98% [interquartile range (IQR) 97-98] and ORi was 0.00 in all patients. At 3 min after starting oxygen administration, the median SpO2 was 100% (IQR 100-100) and the median ORi was 0.50 (IQR 0.42-0.57). There was an SpO2 decline of 1% or more from the peak value after propofol administration in 13 patients, and 32.5 s (IQR 18.8-51.3) before the SpO2 decrease, ORi began to decline in 10 of the 13 (77%) patients. The ORi trends enable us to predict oxygenation reduction approximately 30 s before SpO2 starts to decline. By monitoring ORi, the incidence related to hypoxemia during RSI could be reduced.

Effects of indigo carmine intravenous injection on oxygen reserve index (ORi™) measurement.

To retrospectively investigate the effects of indigo carmine intravenous injection on oxygen reserve index (ORi™) in 20 patients who underwent elective gynecologic surgery under general anesthesia. The study subjects were patients who underwent elective gynecologic surgery under general anesthesia between April 2016 and January 2017, and were administered a 5-ml intravenous injection of 0.4% indigo carmine for clinical purposes during surgery with ORi monitoring. Changes in ORi within 20 min after indigo carmine injection were observed. A relevant decrease in ORi was defined as ≥ 10% reduction in ORi from pre-injection level. ORi rapidly decreased after indigo carmine intravenous injection in all patients. In 10 of 19 patients, ORi decreased to 0 after indigo carmine injection. The median lowest value of ORi was 0 (range 0-0.16) and the median time to reach the lowest value of ORi was 2 min (range 1-4 min) after injection. ORi values returned to pre-injection levels within 20 min in 13 of 19 patients, and the median time to return to pre-injection levels was 10 min (range 6-16 min) after injection. During ORi monitoring it is necessary to consider the rapid reduction in ORi after intravenous injection of indigo carmine.

Evaluation of pharmacokinetic models of intravenous dexmedetomidine in sedated patients under spinal anesthesia.

PURPOSE: Little information is available on the predictive ability of previously published pharmacokinetic models of dexmedetomidine in patients under spinal anesthesia. We evaluated nine published pharmacokinetic models that were constructed in different study settings. METHODS: Sixteen patients received dexmedetomidine infusions after spinal anesthesia according to the manufacturer's recommended regimen (6 µg/kg/h over 10 min followed by 0.2-0.7 µg/kg/h) or target-controlled infusion (initial target of 1.5 ng/ml using the Dyck model). Dexmedetomidine concentrations were measured and median performance error (MDPE), median absolute performance error (MDAPE), and wobble were calculated. RESULTS: A total of 84 blood samples were analyzed. The pharmacokinetic model reported by Hannivoort et al. had the greatest ability to predict dexmedetomidine concentrations (MDPE 5.6%, MDAPE 18.1%, and wobble 6.2%). CONCLUSIONS: Hannivoort et al.'s pharmacokinetic model, constructed with a dataset obtained from healthy volunteers, can predict dexmedetomidine concentrations best during continuous infusion under spinal anesthesia.

Correction to: Evaluation of pharmacokinetic models of intravenous dexmedetomidine in sedated patients under spinal anesthesia.

Inadvertently, the reference [8] was published incorrectly in the original publication of the article. The correct reference [8] is provided below.

Effects of indigo carmine intravenous injection on noninvasive and continuous total hemoglobin measurement with using the Revision L sensor.

The effects of intravenous injection of indigo carmine on noninvasive and continuous total hemoglobin (SpHb) measurement were retrospectively evaluated with the Revision L sensor. The subjects were 18 patients who underwent elective gynecologic surgery under general anesthesia. During surgery, 5 mL of 0.4 % indigo carmine was injected intravenously, and changes in SpHb concentrations between before and after the injection were evaluated. The mean age was 52.4 ± 12.8 years. Before injection, the median SpHb level was 10.1 (range, 6.8-13.4) g/dL. The results demonstrated no change in SpHb concentration between before and after indigo carmine injection as detected by the Revision L sensor. SpHb measurements as determined with the Revision L sensor were not affected, even after the intravenous injection of indigo carmine.

Population pharmacokinetics of intravenous acetaminophen in Japanese patients undergoing elective surgery.

INTRODUCTION: Intravenous (i.v.) acetaminophen is administered during surgery for postoperative analgesia. However, little information is available on the pharmacokinetics of i.v. acetaminophen in Japanese patients undergoing surgery under general anesthesia. METHODS: The study was approved by the Institutional Review Board and registered at UMIN-CTR (UMIN000013418). Patients scheduled to undergo elective surgery under general anesthesia were enrolled after obtaining written informed consent. During surgery, 1 g of i.v. acetaminophen was administered over 15, 60, or 120 min. Acetaminophen concentrations (15 or 16 samples per case) were measured at time points from 0-480 min after the start of administration (liquid chromatography-mass spectrometry/tandem mass spectrometry; limit of quantitation 0.1 µg/mL). The predictive performance of three published pharmacokinetic models was evaluated. Population pharmacokinetics were also analyzed using a nonlinear mixed-effect model based on the NONMEM program. RESULTS: Data from 12 patients who underwent endoscopic or lower limb procedures were analyzed (male/female = 7/5, median age 55 years, weight 63 kg). Anesthesia was maintained with remifentanil and propofol or sevoflurane. The pharmacokinetic model of i.v. acetaminophen reported by Würthwein et al. worked well. Using 185 datapoints, the pharmacokinetics of i.v. acetaminophen were described by a two-compartment model with weight as a covariate but not age, sex, or creatinine clearance. The median prediction error and median absolute prediction error of the final model were -1 and 10%, respectively. CONCLUSION: A population pharmacokinetic model of i.v. acetaminophen in Japanese patients was constructed, with performance within acceptable ranges.

Effects of indigo carmine intravenous injection on noninvasive and continuous total hemoglobin measurement.

The effects of an intravenous injection of indigo carmine on noninvasive and continuous total hemoglobin (SpHb) measurement were retrospectively evaluated. The subjects were 21 patients who underwent elective gynecologic surgery under general anesthesia. During surgery, 5 mL of 0.4 % indigo carmine was intravenously injected, and subsequent changes in SpHb concentrations were evaluated. The results demonstrate that the pre-injection SpHb level was 10 g/dL, and the minimum post-injection SpHb level was 8.3 g/dL. The amount of decrease was 1.8 g/dL. The time to reach the minimum value was 4 min, and the time to return to the pre-injection value was 15 min. The decrease in SpHb was greater in the group with a perfusion index (PI) < 1.4 than in the group with a PI > 1.4. The assessment of SpHb after an intravenous injection of indigo carmine necessitates caution.

Plasma ropivacaine concentration following ultrasound-guided subcostal transversus abdominis plane block in adults.

Ultrasound-guided subcostal transversus abdominis plane block (TAPB) is widely used for abdominal surgery; however, arterial plasma concentration of the anesthetic ropivacaine after the blockade is still unclear. We evaluated ropivacaine concentration after subcostal TAPB in adult patients undergoing upper abdominal surgery. Twelve patients with American Society of Anesthesiologists physical status 1-2 were enrolled. They received ultrasound-guided subcostal TAPB with 0.45 % ropivacaine at 3 mg/kg. Arterial plasma samples were collected at 15, 30, 45, 60, 90, and 120 min after the blockade and analyzed for total ropivacaine concentration using liquid chromatography and mass spectrometry. At every time point, the maximum concentrations (C(max)), and time to the C max (T(max)) were recorded. The mean C(max) and T(max) were 1.87 (0.78) µg/ml and 31.3 (16.7) min, respectively. No adverse events or clinical symptoms indicating systemic toxicity were observed during this study. The study demonstrated that administration of ropivacaine at 3 mg/kg during subcostal TAPB led to rapid increases in plasma concentration of the anesthetic during the first 2 h after the blockade. C(max) nearly reached the threshold for systemic toxicity.