Explore the vast range of titles available.

Arterial stiffness due to vascular aging is a major indicator during the assessment of cardiovascular risk. In this study, we propose a method for age estimation by applying deep learning to a photoplethysmogram (PPG) for the non-invasive assessment of the vascular age. The proposed deep learning-based age estimation model consists of three convolutional layers and two fully connected layers, and was developed as an explainable artificial intelligence model with Grad-Cam to explain the contribution of the PPG waveform characteristic to vascular age estimation. The deep learning model was developed using a segmented PPG by pulse from a total of 752 adults aged 20–89 years, and the performance was quantitatively evaluated using the mean absolute error, root-mean-squared-error, Pearson’s correlation coefficient, and coefficient of determination between the actual and estimated ages. As a result, a mean absolute error of 8.1 years, root mean squared error of 10.0 years, correlation coefficient of 0.61, and coefficient of determination of 0.37, were obtained. A Grad-Cam, used to determine the weight that the input signal contributes to the result, was employed to verify the contribution to the age estimation of the PPG segment, which was high around the systolic peak. The results of this study suggest that a convolutional-neural-network-based explainable artificial intelligence model outperforms existing models without an additional feature detection process. Moreover, it can provide a rationale for PPG-based vascular aging assessment.

•An additional intravenous dose of ramosetron once daily until the second-day post-surgery did not reduce the incidence of PONV in female patients undergoing breast surgery compared to the standard intravenous dose (0.3 mg) of ramosetron administered only once immediately before the end of surgery.•In predicting the occurrence of PONV, the Apfel model showed high sensitivity; however, its specificity and accuracy were lower than ML-based models.•In an adjusted analysis using a logistic regression model, the history of PONV or motion sickness and ASA were significant risk factors for PONV, and the odds ratio was high in this order. The study aimed to compare the postoperative nausea and vomiting (PONV) preventive effect of repeated administration of ramosetron with the standard treatment group and compare models to predict the incidence of PONV using machine-learning techniques. A total of 261 patients scheduled for breast surgery were analyzed to evaluate the effectiveness of repeated intravenous administration of ramosetron. All patients were administered 0.3 mg ramosetron just before the end of surgery. For the repeated dose of ramosetron group, an additional dose of 0.3 mg was administered at 4, 22, and 46 hours after the end of the surgery. Postoperative nausea, vomiting, and retching were evaluated using the Rhodes Index of Nausea, Vomiting, and Retching at 6, 24, and 48 hours postoperatively. Previously published randomized controlled data were combined with the data of this study to create a new dataset of 1390 patients, and machine-learning–based PONV prediction models (classification tree, random forest, extreme gradient boosting, and neural network) was constructed and compared with the Apfel model. Fifty patients (38.5%) and 60 patients (45.8%) reported nausea, vomiting, or retching 48 hours postoperatively in the standard and repeated-dose groups, respectively (P = 0.317, χ2 test). Median sensitivity, specificity, and accuracy of the Apfel model analyzed using the training set were 0.815, 0.344, and 0.495, respectively. The repeated administration of ramosetron did not reduce the incidence of PONV. The Apfel model had high sensitivity, however, its specificity and accuracy were lower than that in machine-learning–based models.

We characterized the volume kinetics of crystalloid solutions (Ringer’s lactate solution and 5% dextrose water) and colloid solutions (6% tetrastarch and 10% pentastarch) by nonlinear mixed-effects modeling in healthy volunteers. We also assessed whether the bioelectrical impedance analysis parameters are significant covariates for volume kinetic parameters. Twelve male volunteers were randomly allocated to four groups, and each group received the four fluid solutions in specified sequences, separated by 1-week intervals to avoid any carryover effects. Volunteers received 40 ml/kg Ringer’s lactate solution, 20 ml/kg 5% dextrose water, 1000 ml 6% tetrastarch, and 1000 ml 10% pentastarch over 1 h. Arterial blood samples were collected to measure the hemoglobin concentration at different time points. Bioelectrical impedance spectroscopy (BIS, INBODY S10, InBody CO., LTD, Seoul, Korea) was also carried out at preset time points. In total, 671 hemoglobin-derived plasma dilution data points were used to determine the volume kinetic characteristics of each fluid. The changes in plasma dilution induced by administration of crystalloid and colloid solutions were well-described by the two-volume and one-volume models, respectively. Extracellular water was a significant covariate for the peripheral volume of distribution at baseline in the volume kinetic model of Ringer’s lactate solution. When the same amount was administered, the colloid solutions had ~4 times more plasma expansion effect than did the crystalloid solutions. Starches with larger molecular weights maintained the volume expansion effect longer than those with smaller molecular weights.

We evaluated the performance of the Surgical Plethysmographic Index (SPI) and the Analgesia Nociception Index (ANI) as surrogate pain measures and determined their respective cut-off values for detecting pain in conscious postoperative patients. In total, 192 patients after elective surgery were enrolled. Baseline SPI and ANI data were acquired for 10 min in the operating room prior to surgery when the patients rated their pain as 0 on the numerical rating scale (NRS). Upon arrival in the post-anaesthesia care unit (PACU) after surgery, SPI and ANI data were recorded for 10 min. The means of the recorded data at OR and PACU were defined as the values representing baseline and postoperative pain, respectively. SPI and ANI data obtained from 189 patients were analysed, who were anesthetized with propofol (n = 149) or sevoflurane (n = 40). Remifentanil was continuously infused intraoperatively in all patients. The values of SPI and ANI were significantly different in conscious patients without (NRS = 0) and with pain (NRS > 0). The areas under the receiver operating curves for SPI and ANI were 0.73 (P < 0.0001) and 0.67 (P < 0.0001), respectively. The cut-off values for SPI and ANI in predicting postoperative pain were 44 (sensitivity: 84%, specificity: 53%) and 63 (sensitivity: 52%, specificity: 82%), respectively, which are different from those suggested by their respective manufacturers for use in intraoperative state under general anaesthesia. The cut-off values of SPI and ANI for detecting pain were similar regardless of the type of anesthesia.

Although commercially available analgesic indices based on biosignal processing have been used to quantify nociception during general anesthesia, their performance is low in conscious patients. Therefore, there is a need to develop a new analgesic index with improved performance to quantify postoperative pain in conscious patients. This study aimed to develop a new analgesic index using photoplethysmogram (PPG) spectrograms and a convolutional neural network (CNN) to objectively assess pain in conscious patients. PPGs were obtained from a group of surgical patients for 6 minutes both in the absence (preoperatively) and in the presence (postoperatively) of pain. Then, the PPG data of the latter 5 minutes were used for analysis. Based on the PPGs and a CNN, we developed a spectrogram-CNN index for pain assessment. The area under the curve (AUC) of the receiver-operating characteristic curve was measured to evaluate the performance of the 2 indices. PPGs from 100 patients were used to develop the spectrogram-CNN index. When there was pain, the mean (95% CI) spectrogram-CNN index value increased significantly-baseline: 28.5 (24.2-30.7) versus recovery area: 65.7 (60.5-68.3); P<.01. The AUC and balanced accuracy were 0.76 and 71.4%, respectively. The spectrogram-CNN index cutoff value for detecting pain was 48, with a sensitivity of 68.3% and specificity of 73.8%. Although there were limitations to the study design, we confirmed that the spectrogram-CNN index can efficiently detect postoperative pain in conscious patients. Further studies are required to assess the spectrogram-CNN index's feasibility and prevent overfitting to various populations, including patients under general anesthesia. Clinical Research Information Service KCT0002080; https://cris.nih.go.kr/cris/search/search_result_st01.jsp?seq=6638.

Measuring complexity from noisy time series provides a crucial insight into the understanding and monitoring of pattern dynamics of complex dynamical systems, including physiological systems such as complex electroencephalogram (EEG) times series observed during anesthesia. We introduce a simple, yet noble complexity measure, called the lumped permutation entropy (LPE) based on the permutation entropy (PE), which allows a tie rank on the pattern formation and shows the robustness under the influence of strong noise, overcoming some limitations of PE and its variants in noisy signals. The robustness of LPE is demonstrated for complex time series from a typical chaotic dynamical system and is applied to empirical electroencephalographic (EEG) data obtained from subjects anesthetized by propofol. In particular, we found that the entropic complexity of EEG time series based on LPE is inversely correlated with plasma concentration of propofol and shows better performance and more robustness than PE and other types of entropic algorithms in indicating the anesthetic depth during the progress of general anesthesia. LPE can be used as complexity measure for real-time monitoring of anesthetic depth during anesthesia.

Traditional pyramidotomy models have a high mortality rate from breathing difficulties and show early recovery from the induced motor deficits. This study establishes a novel pyramidotomy technique in Sprague Dawley rats that generates persistent motor deficits and has a reduced mortality rate. We used viral neural tracing to identify the course and relative distribution of forelimb and hindlimb motor fibers (n = 9). On basis of the neural tracing data, the medullary pyramid was targeted dorsally from the cerebellar cortex for photothrombotic infarct lesioning (n = 18). The photothrombotic technique selectively destroyed the corticospinal fibers in the medullary pyramid with relative preservation of neighboring grey-matter tissue. MicroPET imaging using 2-deoxy-2-[18F]-fluoro-D-glucose (FDG-microPET) showed a decrease in regional cerebral glucose metabolism (rCGM) in the bilateral pyramid and ipsilateral sensory cortex (p < 0.001, FDR q < 0.05). In addition, the trapezoid bodies and superior olivary nuclei showed a decrease in rCGM, compatible with damage caused during the introduction of the optical fiber. Connected structures such as the inferior colliculi and auditory cortices also showed decreases in rCGM in both hemispheres (p < 0.001, FDR q < 0.05). There was a significant and persistent decrease in motor and sensory function in the contralateral limb following pyramidotomy, as demonstrated by performance in the single pellet reaching task and the foot-fault test. There was no operative mortality or loss of respiratory function in this study. These results indicate that photothrombotic pyramidotomy with a dorsal transcortical approach is a safe and reliable technique for generating a pyramidotomy model with persistent motor deficits.

In Korea, the approved anesthetic regimen of remimazolam starts with 6 mg/kg/h or 12 mg/kg/h until loss of consciousness, followed by maintenance at 1–2 mg/kg/h. Some patients receiving remimazolam for general anesthesia experience occasional difficulty maintaining bispectral index (BIS) value ˂ 60. This retrospective study aimed to analyze the data from patients undergoing elective surgery under remimazolam based-general anesthesia to determine the frequency and physical characteristics of patients with BIS values ˂ 60. The criterion was established for patients with a poorly maintained BIS value < 60. The frequency and physical characteristics of patients who satisfied this criterion were investigated through their medical records. The modified Brice interview was conducted within 24 h after surgery. Among the 1500 patients included in the analysis, 61 (4.1%) met the criteria for BIS ˂ 60. Based on the modified Brice interview, none of the patients with poorly maintained BIS ˂ 60 complained of intraoperative awareness based on the modified Brice interview or exhibit specific physical characteristics. These patients accounted for less than 5% of the total population studied. Notably, physical characteristics alone are insufficient to predict such patients before surgery.

Background Prophylactic parenteral administration of antibiotics is strongly recommended to prevent surgical site infection (SSI). Cefoxitin is mainly administered intravenously in colorectal surgery. The current standard method for administering prophylactic antibiotics in adults is to administer a fixed dose quickly before skin incision. The percentage of time that the unbound concentration is maintained above the minimum inhibitory concentration ( f T > MIC) during surgery is used as a surrogate measure for the effectiveness of prophylactic antibiotics. Target-controlled infusion (TCI) is a method of administration that changes the infusion rate to maintain a constant target concentration set by the user in consideration of the patient’s physical characteristics. When cefoxitin is administered using the TCI method, it is possible that f T > MIC can be well maintained while reflecting the patient’s physical characteristics compared to the standard method. Methods This prospective, single-centre, parallel-arm, single-blinded, randomised controlled trial with a 1:1 allocation was designed to compare the effectiveness of the TCI method with that of the standard cefoxitin administration method. We shall enrol 2494 patients scheduled to undergo colon or rectal surgery. Prior to the procedure, we shall randomise each patient to the control group (standard administration method) or study group (TCI method). In the control group, 2 g of cefoxitin was dissolved in 100 ml of normal saline and administered for approximately 10 min. Redosing was performed every 2 h from the start of the first dose of cefoxitin. In the study group, 2 g of cefoxitin was dissolved in 50 ml of normal saline and administered using a commercialised TCI syringe pump until the end of surgery. It was administered at a target concentration of 80 μg/ml using the total concentration pharmacokinetic model of cefoxitin. In all groups, 2 g of cefoxitin was administered using the standard administration method 12 h after the end of surgery. The primary outcome will be the incidence of SSI. The secondary outcome will be the administered dose of cefoxitin. Preoperative, intraoperative, and postoperative data were collected. Discussion This study will provide evidence for the effectiveness of administering cefoxitin using the TCI method compared to the standard method. Trial registration ClinicalTrials.gov, NCT05253339 , Registered on February 23, 2022 {2a, 2b}.

Remimazolam, a novel hypnotic agent, has demonstrated superior hemodynamic stability compared with propofol during general anesthesia, particularly in elderly patients. However, the dose-dependent reduction in blood pressure associated with remimazolam has not been quantitatively modeled in this population. We analyzed data from 432 patients aged ≥ 65 years who underwent elective gastrectomy as part of a randomized trial comparing remimazolam with propofol. Remimazolam was administered via zero-order infusion at 6 mg/kg/h, whereas propofol was delivered using target-controlled infusion (TCI) guided by the Schnider model. Blood pressure data were transformed into fractional changes in mean arterial pressure (MBP) relative to baseline. A modified simple logistic regression model was developed to characterize the relationship between cumulative remimazolam dose and MBP reduction, with body weight evaluated as a covariate. A total of 209 patients were analyzed in each group. The modified logistic model effectively described the dose-dependent MBP reduction associated with remimazolam. Body weight was identified as a significant covariate that improved model performance. Although the remimazolam group exhibited a statistically greater MBP reduction before intubation than the propofol group (28.0 ± 9.9% vs 25.8 ± 10.1% reduction from baseline,  = 0.024), the difference was not considered clinically meaningful. In elderly patients undergoing general anesthesia with remimazolam, the relationship between dose and MBP reduction during induction was well characterized using a modified logistic model, with body weight as a significant covariate. TCI may represent an effective dosing strategy for maintaining hemodynamic stability during anesthetic induction. This study was registered at the Clinical Research Information Service of the Korean National Institute of Health (CRIS, http://cris.nih.go.kr), with registration number KCT0006877, on December 27, 2021.