Drainage Rate Research Articles

Construction Method of Honeycomb Gas Flow Network Channel: Structure-Based and Engineering Response on Plastic Zone Distribution Form

The plastic zone of the surrounding rock of the borehole is a high-quality channel for gas flow. Studying the distribution form of the plastic zone in the surrounding rock of the boreholes and the characteristics of the extended connection network is essential for the optimal layout of the gas drainage boreholes. Considering gas pressure parameters based on the modified Terzaghi effective stress principle and Mohr–Coulomb strength criterion. The implicit equation of the plastic zone boundary of the surrounding rock of the borehole is derived. The influence of two-way confining pressure ratio, coal body strength, gas pressure and hole diameter on the distribution of the surrounding plastic rock zone and the permeability-increasing circle is analyzed, and a honeycomb gas flow network channel structure based on the distribution of plastic zones is constructed. The gas flow and enrichment zone of the coal seam are connected, and the gas drainage rate is improved.

An Improved Emergency Blow Theoretical Model for Naval Submarine Blowing System and Experimental Verification

_ An improved emergency blow model is proposed, which is based on the traditional emergency blow model and takes into account the influence of compressed air overflows from flood holes in the later stage of blowing. In order to verify the prediction accuracy of the improved emergency blow model for tank blowing, the full-scale model experiment of tank blowing was conducted to investigate the effects of air source volume, air source initial pressure, and flood holes diameters on blowing. The process of air release from bottle and main ballast tank drainage can be accurately simulated by the improved emergency blow model, and the prediction error of tank air peak pressure is shown to be <10%. Additionally, it is found that the air source volume has no effect on the tank’s air peak pressure or tank drainage rate. By analyzing the dynamic characteristics of tank air pressure, it is found that the dynamic change trend of air pressure differs between flood holes with small and large diameters. In the small diameter conditions, the air pressure reaches the maximum when the compressed air just enters the tank; however, under large diameter conditions, the peak pressure comes before the accumulated air pressure is released. The experiment and simulation demonstrate that increasing the area of the flood holes has a decreasing effect on the amount of air accumulated in the tank, and that the decreasing effect becomes more pronounced as the air source initial pressure increases. Introduction To carry out military operations, submarines are deployed both underwater and close to the open surface. About 170 submarines have sunk since they were originally created as a result of an accident, such as a fire, explosion, malfunction, grounding, or collision (Park & Kim 2017). Submarines run the risk of losing safety control in these critical situations. The best method of self-rescue is emergency floating to the surface to prevent bottoming or going deeper than allowed (Liu et al. 2009). A key factor in emergency rising to the water’s surface is the compressed air blowing mechanism. In such an operation, supplying air to the main ballast tank and blowing out ballast water should be used to achieve positive buoyancy or recover a positive pitching moment, which can be used to restore the safe depth of the submarine. Emergency blow is the term used to describe the process of directly supplying air to the main ballast tank without using a high-pressure valve column. The emergency blow is explored in this work because its influence is significantly greater than that of usual blowing, or traditional blowing.

The stability of magnetic soap films

Although previous studies have shown that a magnetic field can drastically alter drainage in soap films containing particles responsive to a magnetic field, which we refer to as magnetic soap films, it is yet to be understood whether a magnetic field may be able to control the rate of drainage and film stability. Furthermore, the effect of a magnetic field on key drainage mechanisms, such as marginal regeneration, is unknown. An experimental investigation involving interferometry is conducted here to develop further understanding of the behavior of horizontal soap films containing magnetite nanoparticles. Three scenarios are considered: soap films, magnetic soap films, and magnetic soap films in an inhomogeneous magnetic field. In each of the three scenarios, high-resolution images capturing the time evolution of each film are acquired, and the lifetime of each film is measured. In addition, a measure of the rate of drainage and the velocities of thin patches of fluid arising from marginal regeneration are evaluated. The results suggest that a magnetic field may be able to have either a stabilizing or destabilizing effect on magnetic soap films, depending on their composition. Furthermore, applying a magnetic field to magnetic soap films alters the trajectory of thin patches of fluid arising from marginal regeneration. This study reveals how a magnetic field can be used in conjunction with magnetic particles to control the stability of soap films, which opens up the possibility for new technologies that require a fine control of film stability.

Investigation of the frequency and risk factors of pulmonary complications following cardiac surgery in the hospital

Objective: The purpose of this study was to determine the frequency of pulmonary complications after heart surgery and to assess the pre-operative, intra-operative and post-operative risk factors. Methods: This was a descriptive and analytical study that was conducted on 244 patients who underwent various cardiac surgeries from December 2021 to May 2022 in Shefa Kerman Hospital. This descriptive/analytical study on patients undergoing heart surgery at Shafa Hospital, Kerman, Iran, from December 2021 to May 2022. Pulmonary complications included atelectasis pneumonia, pleural effusion, long-term mechanical ventilation, and respiratory failure. The pre-operative, intra-operative and post-operative risk factors were investigated in the present study. SPSS software was used to analyze the data. Logistic regression analysis was employed to determine the relationship between risk factors and the incidence of lung complications. Results: In the present study, 55 patients (22.5%) had pulmonary complications, followed by prolonged mechanical ventilation (13.1%), pneumonia (11.5%), respiratory failure (4.1%), pleural effusion (11.1%) and atelectasis (6.1%). Pulmonary complications after heart surgery were associated with days of ICU stay, post-operative stroke, post-operative acute kidney injury, emergency surgery, FFP injection, high drainage rate, and mitral valve replacement surgery (all p <0.001). 4% of patients died after surgery, which was statistically related to pulmonary complications (P<0.0001). The results of multivariable logistic regression test showed that FFP injection, type of heart surgery, hypertension, ICU stay days are capable of predicting pulmonary complications after heart surgery. Conclusion: Mortality was found to be higher in patients with pulmonary complications. Based on the results of the regression analysis, FFP injection, type of surgery, history of hypertension and length of ICU stay were independent risk factors of pulmonary complications.

Sentinel node-assisted neck dissection in advanced oral squamous cell carcinoma-A new protocol for staging and treatment.

Sentinel lymph node biopsy (SLNB) is used to improve the staging of and guide treatment in patients with early-stage T1-T2 N0 oral squamous cell carcinoma (OSCC). The role of sentinel nodes (SNs) and the use of SN-technique in advanced OSCC (T3-T4 and/or N+) remain to be evaluated. This study investigates the nodal drainage and the rate of positive SNs (SNs+) in all stages of OSCC. In total, 85 patients with T1-T4 OSCC diagnosed 2019-2021 were included. We used a prolonged interval between peritumoral injection of radionuclide and SPECT-CT to include all SNs. Patients with advanced OSCC presented a higher proportion of contralateral lymphatic drainage and a higher rate of SN+ compared to patients with early-stage disease. T3-T4 and N+ tumors presented a tendency for a higher rate of contralateral lymphatic drainage compared to T1-T2 and N0 tumors (p = 0.1). The prevalence of positive nodes (SNs+) was higher among patients with advanced disease, T3-T4 versus T1-T2 (p = 0.0398). SN-assisted ND enables identification and removal of all SNs + and has the potential for more accurate staging and could possibly give prognostic advantages regarding regional recurrence for all OSCC patients, especially among those with advanced disease. The precise localization of the SNs + also suggests that a more individualized ND approach might be possible in the future even for patients with advanced OSCC.

Competitive adsorption effect during spontaneous external water imbibition in loaded gas-bearing coal and application of a normalized desorption rate model

The competitive adsorption effect of water and gas during the coal seam water injection process plays an important role in improving the coalbed methane (CBM) drainage rate of coal seams that do not meet the standards for gas drainage. However, competitive adsorption mainly occurs in the spontaneous imbibition process for coal seam water injection, which is not clear under the dual action of ground stress and gas pressure during spontaneous imbibition process. Here, some spontaneous imbibition experiments under isobaric water addition and isobaric desorption conditions are conducted using a spontaneous imbibition experimental system. The obtained results are as follows. (1) The accumulated replacement gas degree is negatively correlated with the gas pressure, which shows that the principle of spontaneous imbibition can be adopted to improve the gas drainage rate for coal seams whose gas drainage is not up to standard. (2) For spontaneous imbibition with loading stress does not change the adsorption pore structure, the average seepage pore diameter is negatively correlated with the wetting range, while the wetting range is positively correlated with the competitive adsorption effect. (3) The spontaneous imbibition process is a process of effectively wetting the pores of gas-bearing coal, which can effectively increase the pore water content and wetting uniformity. (4) A normalized desorption rate model of the relative replacement degree during spontaneous imbibition is established based on the dimensionless method. This study provides a technical method for improving the gas drainage rate for the drainage of substandard low-permeability coal seams.

Endoscopic Ultrasound-Guided Biliary Drainage

Endoscopic retrograde cholangiopancreatography (ERCP) and percutaneous transhepatic biliary drainage (PTBD) are currently first- and second-line therapeutic options, respectively, for the relief of biliary obstruction. In recent years, however, endoscopic ultrasound-guided biliary drainage (EUS-BD) has become an established alternative therapy for biliary obstruction. There are multiple different techniques for EUS-BD, which can be distinguished based on the access point within the biliary tree (intrahepatic versus extrahepatic) and the location of stent placement (transenteric versus transpapillary). The clinical and technical success rates of biliary drainage for EUS-BD are similar to both ERCP and PTBD, and complication rates are favorable for EUS-BD relative to PTBD. As EUS-BD becomes more widely practiced and endoscopic tools continue to advance, the outcomes will likely improve, and the breadth of indications for EUS-BD will continue to expand.

In situ formation of injectable organogels for punctal occlusion and sustained release of therapeutics: design, preparation, in vitro and in vivo evaluation

The treatment of dry eye mainly includes instillation of cyclosporine A (CsA) nanoemulsion or the use of punctal plugs. Therefore, in this study, a novel injectable in situ organogel plug was developed using CsA as a model drug, stearic acid, injectable soybean oil, and N-methyl-2-pyrrolidinone (NMP) (1.25:10:0.6, w/v/v) as gel materials, to provide a dual mechanism for dry eye treatment. The formulated CsA injectable in situ organogel (CsA-OG) was evaluated in terms of stability, in vitro release, rheology, ocular irritation, punctal occlusion tests, and ocular distribution assessment. In vivo ocular distribution investigations showed that CsA-OG achieved considerably higher Cmax (1.94, 1.92 and 1.97-fold respectively) and AUC0-72h in the cornea, conjunctiva, and sclera (2.49, 2.27 and 2.15-fold respectively) than ciclosporin eye drops (p < 0.05). In vitro model evaluation demonstrated significant decrease in flow flux to 52.78 % at 2 min after CsA-OG injection. According to evaluation of the in vivo model, the organogel plug can completely block the lacrimal passages and greatly decrease the lacrimal drainage rate (p < 0.05). The above results suggest that these intracanalicular CsA-OG plugs can offer more extensive clinical applications than existing lacrimal drainage plugs and may act as a drug delivery system.

Comparison of endoscopic retrograde cholangiopancreatography outcomes between cap-fitted forward and side viewing endoscopes in patients with Billroth II anastomosis

BackgroundThere have been no previous studies that directly compared outcomes between cap-fitted forward-viewing and side viewing endoscopes (SE). This study aimed to compare the technical success rate and occurrence of adverse events between the side viewing and cap-fitted forward-viewing endoscope (CE) groups among patients with Billroth II anatomy who underwent ERCP.MethodsThe medical records of patients with a previous history of subtotal gastrectomy using Billroth II reconstruction who underwent ERCP at Yeungnam University Hospital between January 2004 and December 2020 were reviewed retrospectively. The patients were divided into CE and SE group. Propensity score matching analysis was performed to minimize selection bias.ResultsPropensity score matching resulted in 55 matched pairs for further analysis. Patients’ characteristics were comparable in the matched cohorts. Final success rate of selective bile duct cannulation was not significantly different between the SE and CE groups (98.2% vs. 94.5%, p = 0.308). The complete CBD stone removal rate in CBD stone and successful biliary drainage rate in malignant biliary obstruction were not significantly different between the two groups. The rate of total ERCP-related adverse events was higher in the CE group than in the SE group, but the difference was not statistically significant (10.9% vs. 7.3%, p = 0.507). Among adverse events, the rate of post-ERCP pancreatitis showed higher tendency in the CE group than in the SE group (10.9% vs. 5.5%, p = 0.297).ConclusionIn conclusion, CE seems to be equally effective as SE for ERCP in patients with Billroth II anatomy. However, attention should be paid to development of post ERCP complications, especially pancreatitis, when performed by CE.

Assessment of Factors Associated With Long-Term Hospitalization in Patients With a Deep Neck Infection.

Deep neck infection (DNI) is a severe infectious disorder of deep neck spaces that can cause serious complications. Long-term hospitalization is when a patient spends more time in the hospital than originally expected for a disease. There are few studies assessing the risk factors associated with long-term hospitalization for a DNI. This study investigated the factors causing DNI patients to experience long-term hospitalization. Long-term hospitalization is defined as a length of hospital stay exceeding 28 days (> 4weeks) in this research. A total of 362 subjects with a DNI between October 2017 and November 2022 were recruited. Among these patients, 20 required long-term hospitalization. The relevant clinical variables were assessed. In a univariate analysis, C-reactive protein (odds ratio [OR] = 1.003, 95% CI: 1.000-1.007, P = .044), involvement of ≥3 deep neck spaces (OR = 2.836, 95% CI: 1.140-7.050, P = .024), and mediastinitis (OR = 8.102, 95% CI: 3.041-21.58, P < .001) were significant risk factors for long-term hospitalization in DNI patients. In a multivariate analysis, mediastinitis (OR = 6.018, 95% CI: 2.058-17.59, P = .001) was a significant independent risk factor for long-term hospitalization for a DNI. There were no significant differences in pathogens between the patients with and without long-term hospitalization (all P > .05). However, the rates of no growth of specific pathogens were significantly different between patients with and without long-term hospitalization, and those with long-term hospitalization had greater rates of growth of specific pathogens (P = .032). The rate of tracheostomy in patients with long-term hospitalization was higher than for those without (P < .001). Nevertheless, the rates of surgical incision and drainage between patients with and without long-term hospitalization did not achieve statistical significance (P = .069). Deep neck infection (DNI) is a critical, life-threatening disease that could lead to long-term hospitalization. The higher CRP and involvement of ≥3 deep neck spaces were significant risk factors in univariate analysis, while concurrent mediastinitis was an independent risk factor associated with long-term hospitalization. We suggest intensive care and prompt airway protection for DNI patients with concurrent mediastinitis.

MP42-09 FAILURE OF TANDEM URETERAL STENTS FOR MALIGNANT URETERAL OBSTRUCTION- WHAT'S NEXT?

You have accessJournal of UrologyCME1 Apr 2023MP42-09 FAILURE OF TANDEM URETERAL STENTS FOR MALIGNANT URETERAL OBSTRUCTION- WHAT'S NEXT? Orel Carmona, Asaf Shvero, Dorit E. Zilberman, Zohar A. Dotan, and Nir Kleinmann Orel CarmonaOrel Carmona More articles by this author , Asaf ShveroAsaf Shvero More articles by this author , Dorit E. ZilbermanDorit E. Zilberman More articles by this author , Zohar A. DotanZohar A. Dotan More articles by this author , and Nir KleinmannNir Kleinmann More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003280.09AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The success rate of drainage with tandem ureteral stents (TUS) for malignant ureteral obstruction (MUO) is 72-87%. Failure of TUS is usually followed by the insertion of a percutaneous nephrostomy tube (PCN). The objective of this study was to examine the possibility of replacing the first-time failed TUS with a new pair of TUS- the success rate of the procedure, and the risk factors for a second failure. METHODS: The medical records of all patients with MUO who underwent balloon dilation and TUS insertion in our institution between 2014-2022 were retrospectively analyzed. Failure of TUS was defined as an episode of urosepsis, recurrent urinary tract infections, acute kidney failure, or detection of new hydronephrosis on imaging scans. Independent risk predictors of failure of secondary TUS were determined by a multivariate cox regression analysis. RESULTS: 240 procedures were performed on 186 patients during the study period. 67 (36%) patients failed for the first time after a median follow-up time of 7 months (IQR 4-17). Of which, 25 (37.4%) patients were drained by a PCN, and 42 (62.6%) were treated by exchanging the TUS with a new pair. Among the patients who underwent a second TUS insertion, 18 (42.8%) did not fail again, and continued to enjoy timely replacements of the TUS. However, 24 (57.2%) patients did fail for the second time and were drained via PCN. In a multivariant analysis, we found that inserting the same diameter TUS as the pair that failed (p=0.002) and time to first failure ≤6 months (p=0.006) were significant risk factors for a second failure of TUS. Cox regression analysis found that distal ureteral stricture predicts shorter time to second failure. During the study period, the group that didn’t fail for a second time underwent 73 replacements of TUS overall (4±2.3 procedures per patient) in a median follow-up time of 19.5 months. CONCLUSIONS: The success rate of replacing TUS after its failure is 42.8%. When replacing failed TUS, one should consider larger-diameter stents. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e570 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Orel Carmona More articles by this author Asaf Shvero More articles by this author Dorit E. Zilberman More articles by this author Zohar A. Dotan More articles by this author Nir Kleinmann More articles by this author Expand All Advertisement PDF downloadLoading ...

Robotic pancreatic necrosectomy and internal drainage for walled-off pancreatic necrosis

BackgroundPancreatic necrosectomy with concomitant internal drainage is a single-stage treatment option for walled-off pancreatic necrosis (WOPN). However, an optimal minimally invasive technique has not been established. We evaluated the safety and single-intervention success rate of robotic pancreatic necrosectomy and internal drainage. MethodsPatients with WOPN undergoing robotic pancreatic necrosectomy and internal drainage at a single institution from 2011-2022 were identified. The primary outcome was the rate of clinical symptom resolution following the index surgical intervention. Results57 patients underwent robotic pancreatic necrosectomy and internal drainage, consisting of robotic cystgastrostomy (RCG, n = 37), robotic cystjejunostomy (RCJ, n = 13) and robotic fistulojejunostomy (RFJ, n = 7). Surgery was performed a median of 102 (range 28–1153) days following the onset of necrotizing pancreatitis. The median operative time was 187 (91–344) minutes and there were 2 (3.5%) conversions. The median length of hospital stay was 4 (2–38) days. Postoperative morbidity was 11%, and there was one (1.8%) 90-day mortality. At a median follow-up of 5.5 months, 53 (93%) patients had clinical symptom resolution after their index procedure and did not require any reintervention. ConclusionIn select patients, robotic pancreatic necrosectomy and internal drainage is safe and achieves a high single-intervention success rate.

The effect of intravenous unit-dose tranexamic acid on visible and hidden blood loss in posterior lumbar interbody fusion: a randomized clinical trial

There are few reports of intravenous unit-dose tranexamic acid (TXA) on the relationship between visible blood loss (VBL) and hidden blood loss (HBL) in posterior lumbar interbody fusion (PLIF). Therefore, the objective of this randomized, prospective, double-blind, single center study was to investigate the effect of intravenous unit-dose TXA on VBL and HBL in patients who underwent PLIF. Among 100 patients, 11 were excluded due to failue to comply with the study, 1 was excluded due to non-conpliance with the study, and 88 were eligible for inclusion in the study. 46 patients who treated with PLIF received unit-dose of TXA (1 g/100 mL) intravenously 15 min before skin incision after general anesthesia (observation group) and 42 patients were given 100 mL of normal saline (control group). The operation time, intraoperative blood loss, postoperative drainage, VBL, HBL, blood transfusion rate, and adverse events were recorded in the two groups. Besides, activated partial prothrombin time (APTT), prothrombin time (PT), thrombin time (TT), fibrinogen (FIB), platelets (PLT), red blood cells (RBC), hemoglobin (HB), hematocrit (HCT), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) on the 1st postoperative day; and RBC, HB, HCT, CRP, ESR on the 4th postoperative day were recorded. All 88 patients successfully completed the operation, the incision healed well, and there was no deep vein thrombosis of the lower extremity after operation. The intraoperative blood loss, postoperative drainage, VBL, HBL, and blood transfusion rate in the observation group were lower than those in the control group, and the differences were statistically significant (p < 0.05). There was no significant difference in operation time between the two groups (p > 0.05). There was no significant difference in postoperative APTT, PT, TT, FIB, PLT, RBC, HB, HCT, CRP and ESR between the two groups (p > 0.05). Intravenous unit-dose TXA is safe and feasible in PLIF, and it can effectively reduce perioperative VBL and HBL.

Surgical treatment of septic arthritis of the hip in children: arthrotomy compared with repeated aspiration-lavage.

To review two cohorts of children treated by two different protocols (repeated needle aspiration-lavage vs. arthrotomy) for surgical treatment of septic arthritis of the hip (SAH). In order to compare between the two methods, the following parameters were checked: (a) Scar cosmesis was assessed by the Patient and Observer Scar Assessment Scale (POSAS). We considered satisfactory results (no scar discomfort) when POSAS was within 10% of the ideal score; (b) 24-h post-operative pain was evaluated by visual analog scale (VAS); (c) Complication rates of incomplete drainage (re-arthrotomy/therapy modification from aspiration-lavage to arthrotomy). The results were evaluated by the Student t-test or by the chi-square test. Seventy-nine children (aged 2-14years) admitted during 2009-2018 and available for at least twoyears of follow-up were enrolled. The POSAS score (range 12-120 points) at the latest follow-up was higher in the arthrotomy group compared with the aspiration-lavage group (18.10 ± 6.22 versus 12.27 ± 1.40, p < 0.001); 77.4% of patients treated by arthrotomy had no scar discomfort. The 24-h post-intervention VAS (range 1-10) was 5.06 ± 1.29 after arthrotomy and 4.03 ± 1.13 after aspiration-lavage, p < 0.04. Complications were three times more frequent in the aspiration-lavage group (8.8% in the arthrotomy group and 26.7% in the aspiration-lavage group, p = 0.045). We conclude that the lower complication rate observed in the arthrotomy group outweighs by far scar cosmesis and post-operative pain advantages in the aspiration-lavage group. Arthrotomy as a drainage method is safer than aspiration-lavage.

Association of Complex Lymphatic Drainage in Head and Neck Cutaneous Melanoma With Sentinel Lymph Node Biopsy Outcomes

Although sentinel lymph node biopsy (SLNB) is a vital staging tool, its application in head and neck melanoma (HNM) is complicated by a higher false-negative rate (FNR) compared with other regions. This may be due to the complex lymphatic drainage in the head and neck. To compare the accuracy, prognostic value, and long-term outcomes of SLNB in HNM with melanoma from the trunk and limb, focusing on the lymphatic drainage pattern. This cohort observational study at a single UK University cancer center included all patients with primary cutaneous melanoma undergoing SLNB between 2010 to 2020. Data analysis was conducted during December 2022. Primary cutaneous melanoma undergoing SLNB between 2010 to 2020. This cohort study compared the FNR (defined as the ratio between false-negative results and the sum of false-negative and true-positive results) and false omission rate (defined as the ratio between false-negative results and the sum of false-negative and true-negative results) for SLNB stratified by 3 body regions (HNM, limb, and trunk). Kaplan-Meier survival analysis was used to compare recurrence-free survival (RFS) and melanoma-specific survival (MSS). Comparative analysis of detected lymph nodes on lymphoscintigraphy (LSG) and SLNB was performed by quantifying lymphatic drainage patterns by number of nodes and lymph node basins. Multivariable Cox proportional hazards regression identified independent risk factors. Overall, 1080 patients were included (552 [51.1%] men, 528 [48.9%] women; median age at diagnosis 59.8 years), with a median (IQR) follow-up 4.8 (IQR, 2.7-7.2) years. Head and neck melanoma had a higher median age at diagnosis (66.2 years) and higher Breslow thickness (2.2 mm). The FNR was highest in HNM (34.5% vs 14.8% trunk or 10.4% limb, respectively). Similarly, the false omission rate was 7.8% in HNM compared with 5.7% trunk or 3.0% limbs. The MSS was no different (HR, 0.81; 95% CI, 0.43-1.53), but RFS was lower in HNM (HR, 0.55; 95% CI, 0.36-0.85). On LSG, patients with HNM had the highest proportion of multiple hotspots (28.6% with ≥3 hotspots vs 23.2% trunk and 7.2% limbs). The RFS was lower for patients with HNM with 3 or more affected lymph nodes found on LSG than those with fewer than 3 affected lymph nodes (HR, 0.37; 95% CI, 0.18-0.77). Cox regression analysis showed head and neck location to be an independent risk factor for RFS (HR, 1.60; 95% CI, 1.01-2.50), but not for MSS (HR, 0.80; 95% CI, 0.35-1.71). This cohort study found higher rates of complex lymphatic drainage, FNR, and regional recurrence in HNM compared with other body sites on long-term follow-up. We advocate considering surveillance imaging for HNM for high-risk melanomas irrespective of sentinel lymph node status.

A Machine Learning Approach for Prediction of the Quantity of Mine Waste Rock Drainage in Areas with Spring Freshet

A new machine learning approach was developed to predict the quantity of mine waste rock drainage using weather data as the inputs. The novelty of the approach is that it includes spring freshet (melting of snow/ice in spring) as an input to the drainage flow rate model. Specifically, the machine learning approach integrates the decision tree algorithm to classify the occurrence or absence of spring freshet and a long short-term memory (LSTM) algorithm to predict the flow rate of mine waste rock drainage. The two algorithms are integrated by using the classification result of spring freshet as an input to the flow rate model. The machine learning approach developed was applied to predict the drainage flow rate at a case study mine in Canada. The model developed was trained with the local weather data as the inputs and the historical monitoring data of drainage flow rate as the target (output). The results show that the decision tree algorithm is able to classify the occurrence or absence of spring freshet with an accuracy of 91%. The inclusion of spring freshet as an input to the flow rate model significantly improves the performance of the flow rate model. The sensitivity tests show that changes in temperature and atmospheric precipitation influence the drainage flow rate.

Effect of percutaneous stenting strategy of unresectable malignant hilar biliary obstruction by three-dimensional reconstruction volumetry.

To explore clinical outcomes of percutaneous stent implantation using volumetric criteria for unresectable malignant hilar biliary obstruction (MHBO). Additionally, aimed to identify the predictors of patients' survival. Seventy-two patients who were initially diagnosed with MHBO between January 2013 to December 2019 in our center were retrospectively included. Patients were stratified according to the drainage achieved ≥50%, <50% of the total liver volume. Patients were divided into two groups: Group A (≥50% drainage), and Group B (<50% drainage). The main outcomes were evaluated in terms of relief of jaundice, effective drainage rate, and survival. Related factors that affect survival were analyzed. 62.5% of the included patients reached effective biliary drainage. The successful drainage rate was significantly higher in Group B than in Group A (p < 0.001). The median overall survival (mOS) of included patients was 6.4months. Patients who received drainage ≥50% of hepatic volume achieved longer mOS than those who received drainage <50% of hepatic volume (7.6months vs. 3.9 months, respectively, p=0. 011). Patients who received effective biliary drainage had longer mOS than those who received ineffective biliary drainage (10.8months vs. 4.4 months, respectively, p < 0.001). Patients who received anticancer treatment had longer mOS than those who only received palliative therapy (8.7months vs. 4.6 months, respectively, p=0.014). In the multivariate analysis, KPS Score ≥ 80 (p=0.037), ≥50% drainage achieved (p=0.038), and effective biliary drainage (p=0.036) were protective prognostic factors that affected patients' survival. Drainage achieved ≥50% of the total liver volume by percutaneous transhepatic biliary stenting seemed to have a higher effective drainage rate in MHBO patients. Effective biliary drainage may create chances for these patients to receive anticancer therapies that seem to provide survival benefits.

Suggested use of empirical antibiotics in acute cholecystitis based on bile microbiology and antibiotic susceptibility

BackgroundBacterial infection is common in acute cholecystitis (AC). To identify appropriate empirical antibiotics, we investigated AC-associated microorganisms and their susceptibilities to antibiotics. We also compared preoperative clinical findings of patients grouped according to specific microorganisms. MethodsPatients who underwent laparoscopic cholecystectomy for AC between 2018 and 2019 were enrolled. Bile cultures and antibiotic susceptibility tests were performed, and clinical findings of patients were noted. ResultsA total of 282 patients were enrolled (147 culture-positive and 135 culture-negative). The most frequent microorganisms were Escherichia (n = 53, 32.7%), Enterococcus (n = 37, 22.8%), Klebsiella (n = 28, 17.3%), and Enterobacter (n = 18, 11.1%). For Gram-negative microorganisms, second-generation cephalosporin (cefotetan: 96.2%) was more effective than third-generation cephalosporin (cefotaxime: 69.8%). Vancomycin and teicoplanin (83.8%) were the most effective antibiotics for Enterococcus. Patients with Enterococcus had higher rates of CBD stones (51.4%, p = 0.001) and biliary drainage (81.1%, p = 0.002), as well as higher levels of liver enzymes, than patients with other microorganisms. Patients with ESBL-producing bacteria had higher rates of CBD stones (36.0% vs. 6.8%, p = 0.001) and biliary drainage (64.0% vs. 32.4%, p = 0.005) than those without. DiscussionPreoperative clinical findings of AC are related to microorganisms in bile samples. Periodic antibiotic susceptibility tests should be conducted to select appropriate empirical antibiotics.

Abstract WP181: Trends In Ischemic Stroke Patients With Central Nervous System Infections: A Propensity Score Matched 20-year Analysis Of The National Inpatient Sample

Introduction: Infection of the central nervous system (CNS) - including meningitis, encephalitis and brain abscess - is a feared complication in hospitalized patients. Studies of CNS infection in patients with acute ischemic stroke (AIS) are scarce. We aimed to characterize AIS patients with CNS infections and assess their clinical outcomes over a 20-year period. Methods: A query of the 2000-2019 National Inpatient Sample was performed for patients admitted with AIS (ICD9 433, 434.01, 434.11, 434.91, ICD-10 I63). Demographics, comorbidities, and outcomes were identified. Univariate analysis with t-tests or chi-square performed as appropriate. A 1:1 nearest neighbor propensity score matched cohort was generated. Variables with standardized mean differences &gt;0.1 used in multivariate regression to generate adjusted odds ratios (AOR)/β-coefficients for the presence of CNS infections on outcomes. Significance set at an alpha level of &lt;0.001. All analysis performed in R version 4.1.3. Results: Total of 10,415,286 patients with AIS were included; 74,731 (0.7%) had CNS infection. Infected patients had higher Elixhauser Comorbidity Score (12.02 ± 9.24 vs. 9.75 ± 8.82; p&lt;0.001) and NIH Stroke Score (8.78 ± 8.86 vs. 6.65 ± 7.29; p&lt;0.001). After propensity matching, these patients had lower rates of smoking, COPD and CKD, and higher rates of systemic inflammatory disease and burr hole drainage (p&lt;0.001). Infected patients had longer hospital stay (3.88 days; 95% CI: 3.45-4.3), higher hospital charges ($49633.46; 95% CI: $44199.59-55067.33) and were less likely to be discharged home or short-term hospital (0.78; 95% CI: 0.74-0.82)(all p&lt;0.001). Conclusion: In this 20 year nationally representative propensity matched analysis of patients with AIS, those with concomitant CNS infections had higher rates of comorbidities and had higher NIHSS. In addition to having longer and more expensive hospital stays, these patients were less likely to have good functional outcomes.

P639 Percutaneous drainage vs surgery as definitive treatment for anastomotic leak after intestinal resection in patients with Crohn’s disease.

Abstract Background Anastomotic leak remains one of the most relevant complications after intestinal resection for Crohn’s disease (CD). While surgery has always been considered the standard treatment for perianastomotic abscess or collection, percutaneous drainage (PD) has been proposed as a potential alternative. The aim of this study was therefore to compare the success rate of percutaneous drainage with that of surgery for the management of anastomotic leak in CD patients. Methods Retrospective, single-centre study including all consecutive patients who were diagnosed with an anastomotic leak as a complication of intestinal resection for CD between 2004 and 2022. Patients requiring emergency surgery due to generalised peritonitis or clinical instability were excluded. Anastomotic leak was defined as a perianastomotic fluid collection confirmed by radiological findings within 30 days from surgery. Patients underwent either PD or surgery as a primary treatment for the complication. The success after PD was defined as the removal of the drainage with clinical and radiological resolution of the complication. The need for further surgical treatment was considered as a failure in both groups. Primary aim: to compare the success rate of PD vs surgery. Secondary aims: to compare the outcomes at 90 days after the procedures; to identify the variables associated with the indication to PD. Results Among the 47 patients included, 25 (53%) underwent PD and 22 (47%) surgery. Table 1 shows the outcomes by the procedure. Success rate was 84% in PD and 95% in surgery group (p=0.20). The median time to success was 14 days after PD (drainage removal) and 12.5 days after surgery (discharge) (p=0.92). Similar rates of post-procedure medical (12% vs 18%, p=0.55) and surgical (24% vs 36%, p=0.62) complications were shown. An ileostomy was required in 91% of surgery cases. At 90 days, similar rates of discharges (100% vs 95%, p=0.28), readmissions (8% vs 0%, p=0.18) and reoperations (16% vs 9%, p=0.48) were observed between PD and surgery cases, respectively. In the multivariate analysis (Table 2), PD was more likely to be performed in patients whose anastomotic leak was diagnosed later after surgery (OR 1.25, 95%CI 1.03-1.53, p=0.027), in those who underwent an ileo-colic anastomosis alone (OR 3.72, 95%CI 2.29-12.45, p=0.034) and in those who were treated after 2016 (OR 6.36, 95%CI 1.04-39.03, p=0.046). Conclusion The present study confirms that PD is a safe and effective procedure to treat anastomotic leak and perianastomotic abscess in CD patients. Surgery, in particular, is associated with a high risk of stoma formation, which would require a subsequent operation. PD should be indicated in all eligible patients as an effective alternative to surgery.