Laser guidance for ultrasound-guided radial artery catheterization using smart glasses: a randomized trial.

PURPOSE: The use of smart glasses during ultrasound-guided needle procedures may reduce operators' head movements but has not been shown to improve procedural performance. Laser guidance has been shown to decrease the time required for ultrasound-guided procedures in phantom models but has not been tested clinically. We hypothesized that adding laser guidance to the use of smart glasses for ultrasound-guided radial artery catheterization using the long axis approach would improve performance by relatively inexperienced users unfamilar with these techniques. METHODS: In an unblinded controlled trial, we enrolled 52 patients requiring radial artery catheterization under anesthesia, randomized into two groups: smart glasses only (SO) (control; N = 26) or smart glasses with laser guidance group (SL) (N = 26). We assessed catheterization time (primary outcome), the number of needle redirections, first-pass success rate, and operator satisfaction (100 = most satisfactory; 0 = unsatisfactory). RESULTS: Comparing the SL with the SO group, catheterization time was shorter (median [interquartile range], 13 [9-20] sec vs 24 [18-46] sec, P < 0.001) and the number of needle redirections was lower (0 [0-1] vs 3 [1-3], P < 0.001) while the first-pass success rate (50% vs 12%, P = 0.007) and operator satisfaction score (85 [76-95] vs 52 [44-74], P < 0.001) were higher. CONCLUSION: Laser guidance improved the performance of ultrasound-guided radial artery catheterization using smart glasses in users inexperienced in the long axis in-plane approach. Nevertheless, it is unclear whether these findings are clinically significant. STUDY REGISTRATION DATE: CRIS.nih.go.kr (KCT0007168); registered 8 April 2022.

RéSUMé: OBJECTIF: L'utilisation de lunettes intelligentes pendant les procédures de ponctions échoguidées peut réduire les mouvements de la tête des opérateurs et opératrices, mais il n'a pas été démontré qu'elle améliorait les performances procédurales. Il a été démontré que le guidage laser réduisait le temps requis pour les interventions échoguidées sur des modèles fantômes, mais cette modalité n'a pas été testée cliniquement. Nous avons émis l'hypothèse que l'ajout d'un guidage laser à l'utilisation de lunettes intelligentes pour le cathétérisme échoguidé de l'artère radiale en utilisant une approche longitudinale (long axe) améliorerait les performances d'utilisateurs et utilisatrices relativement inexpérimenté·es et peu familier·ères avec ces techniques. MéTHODE: Dans une étude contrôlée sans insu, nous avons recruté et randomisé en deux groupes 52 patient·es nécessitant un cathétérisme de l'artère radiale sous anesthésie : lunettes intelligentes uniquement (LIU) (témoin N = 26) ou lunettes intelligentes avec guidage laser (LIL) (N = 26). Nous avons évalué le temps de cathétérisme (critère d'évaluation principal), le nombre de réorientation d'aiguilles, le taux de réussite au premier passage et la satisfaction de l'opérateur·trice (100 = le plus satisfaisant; 0 = insatisfaisant). RéSULTATS: En comparant le groupe LIL au groupe LIU, le temps de cathétérisme était plus court (médiane [écart interquartile], 13 [9-20] sec vs 24 [18­46] sec, P < 0,001) et le nombre de réorientations d'aiguilles était plus faible (0 [0­1] vs 3 [1­3], P < 0,001), tandis que le taux de réussite au premier passage (50 % vs 12 %, P = 0,007) et le score de satisfaction des opératrices et opérateurs (85 [76­95] vs 52 [44­74], P < 0,001) étaient plus élevés. CONCLUSION: Le guidage laser à l'aide de lunettes intelligentes a amélioré les performances du cathétérisme échoguidé de l'artère radiale chez des utilisateurs et utilisatrices inexpérimenté·es en approche longitudinale. Nous ne pouvons toutefois pas déterminer si ces résultats sont cliniquement significatifs. DATE D'ENREGISTREMENT DE L'éTUDE: CRIS.nih.go.kr (KCT0007168); enregistré le 8 avril 2022.

Dextroplantation of Left Liver Graft in Infants.

The position of the left side liver graft is important, and it could lead to complications of the hepatic vein (HV) and portal vein (PV), especially in a small child using a variant left lateral section (vLLS) graft. The purpose of this study was to evaluate the outcome of a novel technique for the implantation of a vLLS graft to the right side (dextroplantation) in infants. For 3 years, 10 consecutive infants underwent dextroplantation using a vLLS graft (group D). The graft was implanted to the right side of the recipient after 90° counterclockwise rotation; the left HV graft was anastomosed to inferior vena cava using the extended right and middle HV stump, and PV was reconstructed using oblique anastomosis without angulation. Surgical outcomes were compared with the historical control group (n = 17, group C) who underwent conventional liver transplantation using a vLLS during infancy. Group D recipients were smaller than group C (body weight <6 kg: 50.0% versus 11.8%; P = 0.03). The rate of graft-to-recipient weight ratio >4% was higher in group D (60.0%) than C (11.8%; P = 0.01). Surgical drains were removed earlier in group D than in group C (15 versus 18 postoperative days [PODs]; P = 0.048). Each group had 1 PV complication (10.0% versus 5.9%); no HV complication occurred in group D, but 3 HV complications (17.6%) occurred in group C (P > 0.05). Hospital stay was shorter in group D than in group C (20 versus 31 PODs; P = 0.02). Dextroplantation of a vLLS graft, even a large-for-size one, was successful in small infants without compromising venous outcomes, compared with conventional vLLS transplantation. We could remove the surgical drains earlier and reduce hospital stays in cases of dextroplantation.

The cumulative duration of bispectral index less than 40 concurrent with hypotension is associated with 90-day postoperative mortality: a retrospective study.

BACKGROUND: The relationship between intraoperative low bispectral index (BIS) values and poor clinical outcomes has been controversial. Intraoperative hypotension is associated with postoperative complication. The purpose of this study was to investigate the influence of intraoperative low BIS values and hypotension on postoperative mortality in patients undergoing major abdominal surgery. METHODS: This retrospective study analyzed 1862 cases of general anesthesia. We collected the cumulative time of BIS values below 20 and 40 as well as electroencephalographic suppression and documented the incidences in which these states were maintained for at least 5 min. Durations of intraoperative mean arterial pressures (MAP) less than 50 mmHg were also recorded. Multivariable logistic regression was used to evaluate the association between suspected risk factors and postoperative mortality. RESULTS: Ninety-day mortality and 180-day mortality were 1.5 and 3.2% respectively. The cumulative time in minutes for BIS values falling below 40 coupled with MAP falling below 50 mmHg was associated with 90-day mortality (odds ratio, 1.26; 95% confidence interval, 1.04-1.53; P = .019). We found no association between BIS related values and 180-day mortality. CONCLUSIONS: The cumulative duration of BIS values less than 40 concurrent with MAP less than 50 mmHg was associated with 90-day postoperative mortality, not 180-day postoperative mortality.

Prediction of Bispectral Index during Target-controlled Infusion of Propofol and Remifentanil: A Deep Learning Approach.

BACKGROUND: The discrepancy between predicted effect-site concentration and measured bispectral index is problematic during intravenous anesthesia with target-controlled infusion of propofol and remifentanil. We hypothesized that bispectral index during total intravenous anesthesia would be more accurately predicted by a deep learning approach. METHODS: Long short-term memory and the feed-forward neural network were sequenced to simulate the pharmacokinetic and pharmacodynamic parts of an empirical model, respectively, to predict intraoperative bispectral index during combined use of propofol and remifentanil. Inputs of long short-term memory were infusion histories of propofol and remifentanil, which were retrieved from target-controlled infusion pumps for 1,800 s at 10-s intervals. Inputs of the feed-forward network were the outputs of long short-term memory and demographic data such as age, sex, weight, and height. The final output of the feed-forward network was the bispectral index. The performance of bispectral index prediction was compared between the deep learning model and previously reported response surface model. RESULTS: The model hyperparameters comprised 8 memory cells in the long short-term memory layer and 16 nodes in the hidden layer of the feed-forward network. The model training and testing were performed with separate data sets of 131 and 100 cases. The concordance correlation coefficient (95% CI) were 0.561 (0.560 to 0.562) in the deep learning model, which was significantly larger than that in the response surface model (0.265 [0.263 to 0.266], P < 0.001). CONCLUSIONS: The deep learning model-predicted bispectral index during target-controlled infusion of propofol and remifentanil more accurately compared to the traditional model. The deep learning approach in anesthetic pharmacology seems promising because of its excellent performance and extensibility.

Reliability of Point-of-Care Hematocrit Measurement During Liver Transplantation.

BACKGROUND: Although point-of-care (POC) analyzers are commonly used during liver transplantation (LT), the accuracy of hematocrit measurement using a POC analyzer has not been evaluated. In this retrospective observational study, we aimed to evaluate the accuracy of hematocrit measurement using a POC analyzer and identify potential contributors to the measurement error and their influence on mistransfusion during LT. METHODS: We retrospectively collected 6461 pairs of simultaneous intraoperative hematocrit measurements using POC analyzers and laboratory devices during LTs in 901 patients. The agreement of hematocrit measurements was assessed using Bland-Altman analysis for repeated measurements, while the incidence and magnitude of hematocrit measurement error were compared among 16 different laboratory abnormality categories. A generalized estimating equation analysis was performed to identify potential contributors to falsely low-measured POC hematocrit. Additionally, we defined potential "overtransfusion" in the case when POC hematocrit was <20% and laboratory hematocrit was ≥20% and investigated its association with intraoperative transfusion. RESULTS: The POC hematocrit measurements were falsely lower than the laboratory hematocrit measurements in 70.3% (4541/6461) of pairs. The median (interquartile range) of hematocrit measurement error was -1.20 (-2.60 to 0.20). Bland-Altman analysis showed that 24.5% (1583/6461) of the errors were outside our a priori defined clinically acceptable limits of ±3%. The incidence of falsely low-measured hematocrit was significantly higher with the presence of concomitant hypoalbuminemia and hypoproteinemia. Hypoalbuminemia combined with hyperglycemia showed significantly larger hematocrit measurement error. Hypoalbuminemia, hypoproteinemia, and hyperglycemia were predictors of falsely low-measured hematocrit. Furthermore, the overtransfusion group showed larger amount of transfusion than the adequately transfused group, with a median difference of 2 units (95% confidence interval [0-4], P = .039), despite similar amount of blood loss. CONCLUSIONS: Hematocrit measured using the POC device tends to be lower than the laboratory hematocrit measured during LT. Commonly encountered laboratory abnormalities during LT include hypoalbuminemia, hypoproteinemia, and hyperglycemia, which may contribute to falsely low-measured POC hematocrit. Careful consideration of these confounders may help reduce overtransfusion that occurs due to falsely low-measured POC hematocrit.

Stroke Volume Variation-Guided Versus Central Venous Pressure-Guided Low Central Venous Pressure With Milrinone During Living Donor Hepatectomy: A Randomized Double-Blinded Clinical Trial.

BACKGROUND: We previously demonstrated the usefulness of milrinone for living donor hepatectomy. However, a less-invasive alternative to central venous catheterization and perioperative contributors to good surgical outcomes remain undetermined. The current study evaluated whether the stroke volume variation (SVV)-guided method can substitute central venous catheterization during milrinone-induced profound vasodilation. METHODS: We randomly assigned 42 living liver donors to receive either SVV guidance or central venous pressure (CVP) guidance to obtain milrinone-induced low CVP. Target SVV of 9% was used as a substitute for CVP of 5 mm Hg. The surgical field grade evaluated by 2 attending surgeons on a 4-point scale was compared between the CVP- and SVV-guided groups (n = 19, total number of scores = 38 per group) as a primary outcome variable. Multivariable analysis was performed to identify independent factors associated with the best surgical field as a post hoc analysis. RESULTS: Surgical field grades, which were either 1 or 2, were not found to be different between the 2 groups via Mann-Whitney U test (P = .358). There was a very weak correlation between SVV and CVP during profound vasodilation such as CVP ≤ 5 mm Hg (R = -0.06; 95% confidence interval, -0.09 to -0.04; P < .001). Additional post hoc analysis suggested that younger age, lower baseline CVP, and longer duration of milrinone infusion might be helpful in providing the best surgical field. CONCLUSIONS: Milrinone-induced vasodilation resulted in favorable surgical environment regardless of guidance methods of low CVP during living donor hepatectomy. However, SVV was not a useful indicator of low CVP because of very weak correlation between SVV and CVP during profound vasodilation. In addition, factors contributing to the best surgical field such as donor age, proactive fasting, and proper dosing of milrinone need to be investigated further, ideally through prospective studies.

Position and relative size of the vertebral artery according to age: Implications for internal jugular vein access.

AIM: The purpose of this retrospective observational study was to investigate the anatomical characteristics of the vertebral artery in pediatric patients using computed tomography images. METHODS: We evaluated anatomical characteristics of the right and left vertebral artery at the cricoid level and at a lower level, which was mid-level between the cricoid cartilage and the origin of vertebral artery from the subclavian artery. At each level, the cross-sectional areas of the vertebral artery and internal jugular vein, the relative size of vertebral artery to internal jugular vein, the minimum distance between them, and the extent of overlap between them were investigated. RESULTS: According to the chest computed tomography images of 344 patients, the sizes of internal jugular vein and vertebral artery were found to increase with age. On the other hand, the relative size of the vertebral artery to internal jugular vein was found to increase conversely with decreasing age. The distance between the vertebral artery and internal jugular vein increased with age at both sides and levels. The vertebral artery was mostly located at the medial side of the internal jugular vein, and overlapped with the internal jugular vein in at least 54% of the patients at the cricoid level and in 74% at the lower level. CONCLUSION: The theoretical risk of vertebral artery puncture is higher in younger children during internal jugular vein catheterization.

Comparative efficacy and safety of anticoagulants for prevention of venous thromboembolism after hip and knee arthroplasty.

Background and purpose - New oral anticoagulants have been developed to prevent venous thromboembolism (VTE) after knee or hip arthroplasty. Although there have been several network meta-analyses (NMA) to compare different regimens, an NMA including 2 different enoxaparin doses and edoxaban has not been performed. Methods - Standard NMA for fondaparinux, dabigatran, rivaroxaban, apixaban, edoxaban, and enoxaparin was performed. Outcome variables included a composite of total VTE and major/clinically relevant bleeding. The rank probabilities of each treatment outcome were summarized by the surface under the cumulative ranking curve. Results - Fondaparinux, rivaroxaban, and apixaban were associated with a reduced risk of VTE compared with enoxaparin, while dabigatran was not. None of these 3 drugs increased bleeding compared with enoxaparin 30 mg twice daily. However, fondaparinux and rivaroxaban increased bleeding compared with enoxaparin 40 mg once daily, while apixaban did not. Apixaban was even associated with decreased major/clinically relevant bleeding compared with enoxaparin 30 mg twice daily or 40 mg once daily. When edoxaban was included in the NMA, edoxaban decreased VTE and did not increase bleeding compared with enoxaparin. Interpretation - A higher efficacy of fondaparinux and rivaroxaban compared with enoxaparin was associated with increased bleeding tendency, while apixaban was superior to enoxaparin regarding both efficacy and safety. A clustered ranking plot showed that apixaban might be the most preferred regarding efficacy and safety. However, our results were driven by indirect statistical inference and were limited by the heterogeneity of the bleeding outcome definitions, drug initiation and continuation, and different surgery types.

Anesthetic management of a pediatric patient with pulmonary arteriovenous fistula undergoing liver transplantation - a case report.

For patients with HPS who require anesthesia for a procedure, HPV should be maintained to prevent worsening hypoxemia. Here, the case of a 9-yr-old girl who was scheduled for a living donor liver transplantation is presented. The patient suffered from end-stage liver disease with HPS due to biliary atresia, which contributed to the development of a diffuse pulmonary AVF. Consequently, anesthetic management of this patient involved two different types of pulmonary shunt. It is important to maintain HPV, not only to prevent worsening of the hypoxia caused by HPS but also to inhibit an increase in PVR that could cause an increase of shunt flow through the pathological fistula. A TIVA technique was performed, and a nitrous oxide inhaler was prepared in case of a possible increase in PVR during the reperfusion period. There were no adverse events during the operation. Thus, anesthesiologists should be aware of the pathophysiological status of HPS and its potential to progress to a pulmonary AVF in order to meticulously determine an anesthesia plan that accounts for the hypoxia and PVR that are associated with HPS.

Pediatric split liver transplantation after Fontan procedure in left isomerism combined with biliary atresia: a case report.

LI is a subset of the heterotaxy syndrome and a rare birth defect that involves the heart and other organs. It can be combined with extracardiac abnormalities, especially BA. CHD can be associated with LI in up to 15% of cases, although it is rare in BA. Pediatric LT for a child with ESLD due to BA combined with LI and CHD is a challenging issue for a transplant surgeon. Herein, we report a successful split LT on a three-yr-old boy with LI who survived after a Fontan procedure due to single ventricle, but who suffered from HPS associated with BA.

Effect of hyperbilirubinemia on the accuracy of continuous non-invasive hemoglobin measurements in liver transplantation recipients.

This study evaluated the effect of hyperbilirubinemia on the accuracy of continuous non-invasive hemoglobin (SpHb) measurements in liver transplantation recipients. Overall, 1465 SpHb and laboratory hemoglobin (Hb) measurement pairs (n = 296 patients) were analyzed. Patients were grouped into normal (< 1.2 mg/dL), mild-to-moderate (1.2-3.0 mg/dL), and severe (> 3.0 mg/dL) hyperbilirubinemia groups based on the preoperative serum total bilirubin levels. Bland-Altman analysis showed a bias of 0.20 (95% limit of agreement, LoA: - 2.59 to 3.00) g/dL, 0.98 (95% LoA: - 1.38 to 3.35) g/dL, and 1.23 (95% LoA: - 1.16 to 3.63) g/dL for the normal, mild-to-moderate, and severe groups, respectively. The four-quadrant plot showed reliable trending ability in all groups (concordance rate > 92%). The rates of possible missed transfusion (SpHb > 7.0 g/dL for Hb < 7.0 g/dL) were higher in the hyperbilirubinemia groups (2%, 7%, and 12% for the normal, mild-to-moderate, and severe group, respectively. all P < 0.001). The possible over-transfusion rate was less than 1% in all groups. In conclusion, the use of SpHb in liver transplantation recipients with preoperative hyperbilirubinemia requires caution due to the positive bias and high risk of missed transfusion. However, the reliable trending ability indicated its potential use in clinical settings.

INSPIRE, a publicly available research dataset for perioperative medicine.

We present the INSPIRE dataset, a publicly available research dataset in perioperative medicine, which includes approximately 130,000 surgical operations at an academic institution in South Korea over a ten-year period between 2011 and 2020. This comprehensive dataset includes patient characteristics such as age, sex, American Society of Anesthesiologists physical status classification, diagnosis, surgical procedure code, department, and type of anaesthesia. The dataset also includes vital signs in the operating theatre, general wards, and intensive care units (ICUs), laboratory results from six months before admission to six months after discharge, and medication during hospitalisation. Complications include total hospital and ICU length of stay and in-hospital death. We hope this dataset will inspire collaborative research and development in perioperative medicine and serve as a reproducible external validation dataset to improve surgical outcomes.

Excellent outcome in 238 consecutive living donor liver transplantations using the right liver graft in a large volume single center.

BACKGROUND: Using a right liver (RL) graft improves the outcomes in adult living donor liver transplantation (ALDLT). Here we report the recent excellent outcomes of 238 consecutive RL transplantations in ALDLT. METHODS: Between January 2005 and June 2009, 238 consecutive adult recipients underwent RL transplantation; The middle hepatic vein (MHV) was reconstructed using artificial vascular grafts in 209 cases. Among these study subjects, UNOS status 1 and 2A were 12 (5.0 %) and 20 (8.4 %) patients, and the mean medical MELD score, was 19.9. Hepatitis B virus was the most common original liver disease in 184 patients (77.3 %). Hepatocellular carcinoma was diagnosed in 133 patients (56.3 %), and 102 patients (76.1 %) met the radiologic Milan criteria. The mean graft-versus-recipient weight ratio was 1.14 %. The primary endpoint of this study was the patient and graft survival rate. The mean follow-up period was 32 (0-69) months. RESULTS: The most common major complication was biliary complication (n = 62; 26 %). The 1-, 2-, and 5-year patient survival rates were 96, 95, and 94 %, and the graft survival rates were 99, 99, and 98 %. There were 4 hospital deaths (1.6 %). Eighteen late mortalities were observed after recurrence of hepatocellular carcinoma (HCC, n = 17) and one case of lymphoma recurrence. One case of graft failure 33 months after ALDLT was attributed to cholestatic fibrosing hepatitis B saved by re-ALDLT. On multivariate analysis, no drainage of MHV branches and accompanying HCC beyond Milan criteria were the risk factors for poor patients' survival rate (p < 0.05). CONCLUSIONS: Further technical innovation would be required to overcome biliary complications. The technical innovation using right liver draining MHV branches improved both patient and graft survival outcomes of ALDLT. Despite these advances, selection criteria for HCC are still hurdles, even in RL transplantation.

Predicting optimal endotracheal tube size and depth in pediatric patients using demographic data and machine learning techniques.

BACKGROUND: Use of endotracheal tubes (ETTs) with appropriate size and depth can help minimize intubation-related complications in pediatric patients. Existing age-based formulae for selecting the optimal ETT size present several inaccuracies. We developed a machine learning model that predicts the optimal size and depth of ETTs in pediatric patients using demographic data, enabling clinical applications. METHODS: Data from 37,057 patients younger than 12 years who underwent general anesthesia with endotracheal intubation were retrospectively analyzed. Gradient boosted regression tree (GBRT) model was developed and compared with traditional age-based formulae. RESULTS: The GBRT model demonstrated the highest macro-averaged F1 scores of 0.502 (95% CI 0.486, 0.568) and 0.669 (95% CI 0.640, 0.694) for predicting the uncuffed and cuffed ETT size (internal diameter [ID]), outperforming the age-based formulae that yielded 0.163 (95% CI 0.140, 0.196, P < 0.001) and 0.392 (95% CI 0.378, 0.406, P < 0.001), respectively. In predicting the ETT depth (distance from tip to lip corner), the GBRT model showed the lowest mean absolute error (MAE) of 0.71 cm (95% CI 0.69, 0.72) and 0.72 cm (95% CI 0.70, 0.74) compared to the age-based formulae that showed an error of 1.18 cm (95% CI 1.16, 1.20, P < 0.001) and 1.34 cm (95% CI 1.31, 1.38, P < 0.001) for uncuffed and cuffed ETT, respectively. CONCLUSIONS: The GBRT model using only demographic data accurately predicted the ETT size and depth. If these results are validated, the model may be practical for predicting optimal ETT size and depth for pediatric patients.

Machine learning-based prediction of intraoperative hypoxemia for pediatric patients.

BACKGROUND: Reducing the duration of intraoperative hypoxemia in pediatric patients by means of rapid detection and early intervention is considered crucial by clinicians. We aimed to develop and validate a machine learning model that can predict intraoperative hypoxemia events 1 min ahead in children undergoing general anesthesia. METHODS: This retrospective study used prospectively collected intraoperative vital signs and parameters from the anesthesia ventilator machine extracted every 2 s in pediatric patients undergoing surgery under general anesthesia between January 2019 and October 2020 in a tertiary academic hospital. Intraoperative hypoxemia was defined as oxygen saturation <95% at any point during surgery. Three common machine learning techniques were employed to develop models using the training dataset: gradient-boosting machine (GBM), long short-term memory (LSTM), and transformer. The performances of the models were compared using the area under the receiver operating characteristics curve using randomly assigned internal testing dataset. We also validated the developed models using temporal holdout dataset. Pediatric patient surgery cases between November 2020 and January 2021 were used. The performances of the models were compared using the area under the receiver operating characteristic curve (AUROC). RESULTS: In total, 1,540 (11.73%) patients with intraoperative hypoxemia out of 13,130 patients' records with 2,367 episodes were included for developing the model dataset. After model development, 200 (13.25%) of the 1,510 patients' records with 289 episodes were used for holdout validation. Among the models developed, the GBM had the highest AUROC of 0.904 (95% confidence interval [CI] 0.902 to 0.906), which was significantly higher than that of the LSTM (0.843, 95% CI 0.840 to 0.846 P < .001) and the transformer model (0.885, 95% CI, 0.882-0.887, P < .001). In holdout validation, GBM also demonstrated best performance with an AUROC of 0.939 (95% CI 0.936 to 0.941) which was better than LSTM (0.904, 95% CI 0.900 to 0.907, P < .001) and the transformer model (0.929, 95% CI 0.926 to 0.932, P < .001). CONCLUSIONS: Machine learning models can be used to predict upcoming intraoperative hypoxemia in real-time based on the biosignals acquired by patient monitors, which can be useful for clinicians for prediction and proactive treatment of hypoxemia in an intraoperative setting.

Serum neutrophil gelatinase-associated lipocalin and lactate level during surgery predict acute kidney injury and early allograft dysfunction after liver transplantation.

Early allograft dysfunction (EAD) and acute kidney injury (AKI) are common and clinically important complications after liver transplantation. Serum lactate level at the end of surgery could predict EAD and neutrophil gelatinase-associated lipocalin (NGAL) is known as a biomarker for AKI after liver transplantation. The authors investigated whether the combination of these two laboratory tests could be used as an early predictor of these two complications of EAD and AKI. We reviewed cases undergoing living donor liver transplantation (n = 353). Lactate-adjusted NGAL level, a combination of these two predictors, was calculated as the sum of each value multiplied by the odds ratio for EAD or AKI. We evaluated whether this combined predictor at the end of surgery is significantly associated with both postoperative AKI or EAD. We compared the area under the receiver operating characteristic curve (AUC) between our multivariable regression models with and without NGAL, lactate, or lactate-adjusted NGAL. NGAL, lactate and lactate-adjusted NGAL are significant predictors for EAD and AKI. The regression model for EAD or AKI including lactate-adjusted NGAL showed a greater AUC (for EAD: odds ratio [OR] 0.88, 95% confidence interval [CI] 0.84-0.91; for AKI: OR 0.89, 95% CI 0.85-0.92) compared to the AUC of the models including lactate (for EAD: OR 0.84, 95% CI 0.81-0.88; for AKI: OR 0.79, 95% CI 0.74-0.83) or NGAL alone (for EAD: OR 0.82, 95% CI 0.77-0.86; for AKI: OR 0.84, 95% CI 0.80-0.88) or the model without lactate or NGAL (for EAD: OR 0.64, 95% CI 0.58-0.69, for AKI: OR 0.75, 95% CI 0.70-0.79). In conclusion, lactate-adjusted NGAL level at the end of surgery could be a reliable combined laboratory predictor for postoperative EAD or AKI after liver transplantation with a greater discriminative ability than lactate or NGAL alone.

Real-time machine learning model to predict in-hospital cardiac arrest using heart rate variability in ICU.

Predicting in-hospital cardiac arrest in patients admitted to an intensive care unit (ICU) allows prompt interventions to improve patient outcomes. We developed and validated a machine learning-based real-time model for in-hospital cardiac arrest predictions using electrocardiogram (ECG)-based heart rate variability (HRV) measures. The HRV measures, including time/frequency domains and nonlinear measures, were calculated from 5 min epochs of ECG signals from ICU patients. A light gradient boosting machine (LGBM) algorithm was used to develop the proposed model for predicting in-hospital cardiac arrest within 0.5-24 h. The LGBM model using 33 HRV measures achieved an area under the receiver operating characteristic curve of 0.881 (95% CI: 0.875-0.887) and an area under the precision-recall curve of 0.104 (95% CI: 0.093-0.116). The most important feature was the baseline width of the triangular interpolation of the RR interval histogram. As our model uses only ECG data, it can be easily applied in clinical practice.

Continuous cuffless blood pressure monitoring using photoplethysmography-based PPG2BP-net for high intrasubject blood pressure variations.

Continuous, comfortable, convenient (C3), and accurate blood pressure (BP) measurement and monitoring are needed for early diagnosis of various cardiovascular diseases. To supplement the limited C3 BP measurement of existing cuff-based BP technologies, though they may achieve reliable accuracy, cuffless BP measurement technologies, such as pulse transit/arrival time, pulse wave analysis, and image processing, have been studied to obtain C3 BP measurement. One of the recent cuffless BP measurement technologies, innovative machine-learning and artificial intelligence-based technologies that can estimate BP by extracting BP-related features from photoplethysmography (PPG)-based waveforms have attracted interdisciplinary attention of the medical and computer scientists owing to their handiness and effectiveness for both C3 and accurate, i.e., C3A, BP measurement. However, C3A BP measurement remains still unattainable because the accuracy of the existing PPG-based BP methods was not sufficiently justified for subject-independent and highly varying BP, which is a typical case in practice. To circumvent this issue, a novel convolutional neural network(CNN)- and calibration-based model (PPG2BP-Net) was designed by using a comparative paired one-dimensional CNN structure to estimate highly varying intrasubject BP. To this end, approximately [Formula: see text], [Formula: see text], and [Formula: see text] of 4185 cleaned, independent subjects from 25,779 surgical cases were used for training, validating, and testing the proposed PPG2BP-Net, respectively and exclusively (i.e., subject-independent modelling). For quantifying the intrasubject BP variation from an initial calibration BP, a novel 'standard deviation of subject-calibration centring (SDS)' metric is proposed wherein high SDS represents high intrasubject BP variation from the calibration BP and vice versa. PPG2BP-Net achieved accurately estimated systolic and diastolic BP values despite high intrasubject variability. In 629-subject data acquired after 20 minutes following the A-line (arterial line) insertion, low error mean and standard deviation of [Formula: see text] and [Formula: see text] for highly varying A-line systolic and diastolic BP values, respectively, where their SDSs are 15.375 and 8.745. This study moves one step forward in developing the C3A cuffless BP estimation devices that enable the push and agile pull services.

Automatic segmentation of atrial fibrillation and flutter in single-lead electrocardiograms by self-supervised learning and Transformer architecture.

OBJECTIVES: Automatic detection of atrial fibrillation and flutter (AF/AFL) is a significant concern in preventing stroke and mitigating hemodynamic instability. Herein, we developed a Transformer-based deep learning model for AF/AFL segmentation in single-lead electrocardiograms (ECGs) by self-supervised learning with masked signal modeling (MSM). MATERIALS AND METHODS: We retrieved data from 11 open-source databases on PhysioNet; 7 of these databases included labeled ECGs, while the other 4 were without labels. Each database contained ECG recordings with durations of ≥30 s. A total of 24 intradialytic ECGs with paroxysmal AF/AFL during 4 h of hemodialysis sessions at Seoul National University Hospital were used for external validation. The model was pretrained by predicting masked areas of ECG signals and fine-tuned by predicting AF/AFL areas. Cross-database validation was used for evaluation, and the intersection over union (IOU) was used as a main performance metric in external database validation. RESULTS: In the 7 labeled databases, the areas marked as AF/AFL constituted 41.1% of the total ECG signals, ranging from 0.19% to 51.31%. In the evaluation per ECG segment, the model achieved IOU values of 0.9254 and 0.9477 for AF/AFL segmentation and other segmentation tasks, respectively. When applied to intradialytic ECGs with paroxysmal AF/AFL, the IOUs for the segmentation of AF/AFL and non-AF/AFL were 0.9896 and 0.9650, respectively. Model performance by different training procedure indicated that pretraining with MSM and the application of an appropriate masking ratio both contributed to the model performance. It also showed higher IOUs of AF/AFL labels than in previous studies when training and test databases were matched. CONCLUSION: The present model with self-supervised learning by MSM performs robustly in segmenting AF/AFL.

Effect of the bevel direction of puncture needle on success rate and complications during internal jugular vein catheterization.

OBJECTIVE: Artery puncture and hematoma formation are the most common immediate complications during internal jugular vein catheterization. This study was performed to assess whether the bevel-down approach of the puncture needle decreases the incidence of posterior venous wall damage and hematoma formation during internal jugular vein catheterization. DESIGN: Prospective, randomized, controlled study. SETTING: A university-affiliated hospital. PATIENTS: Three hundred thirty-eight patients for scheduled for thoracic surgery requiring central venous catheterization in the right internal jugular vein. INTERVENTIONS: Patients requiring internal jugular vein catheterization were enrolled and randomized to either the bevel-down group (n = 169) or the bevel-up group (n = 169). All patients were placed in the Trendelenburg position with the head turned to the left. After identifying the right internal jugular vein with ultrasound imaging, a double-lumen central venous catheter was inserted using the modified Seldinger technique. Venous entry of the needle was recognized by return of venous blood during needle advance or withdrawal. The internal jugular vein was assessed cross-sectionally and longitudinally after catheterization to identify any complications. A p value of <.05 was considered to be statistically significant. MEASUREMENTS AND MAIN RESULTS: There was no difference in the incidence of the puncture-on-withdrawal between the two groups (37 of 169 in the bevel-down group and 25 of 169 in the bevel-up group). However, the incidence of posterior hematoma formation was lower in the bevel-down group (six of 169 vs. 17 of 169, p = .031). Additionally, there was less incidence of the posterior hematoma formation associated with puncture-on-withdrawal in the bevel-down group (six of 37 vs. 11 of 25, p = .034). CONCLUSIONS: The bevel-down approach of the right internal jugular vein may decrease the incidence of posterior venous wall damage and hematoma formation compared with the bevel-up approach, which implicates a reduced probability of carotid artery puncture with the bevel-down approach during internal jugular vein catheterization.