Diagnosis of Fault Modes Masked by Control Loops with an Application to Autonomous Hovercraft Systems

This paper introduces a methodology for the design, testing and assessment of incipient failure detection techniques for failing components/systems of an autonomous vehicle masked or hidden by feedback control loops. It is recognized that the optimum operation of critical assets (aircraft, autonomous systems, etc.) may be compromised by feedback control loops by masking severe fault modes while compensating for typical disturbances. Detrimental consequences of such occurrences include the inability to detect expeditiously and accurately incipient failures, loss of control and inefficient operation of assets in the form of fuel overconsumption and adverse environmental impact. We pursue a systems engineering process to design, construct and test an autonomous hovercraft instrumented appropriately for improved autonomy. Hidden fault modes are detected with performance guarantees by invoking a Bayesian estimation approach called particle filtering. Simulation and experimental studies are employed to demonstrate the efficacy of the proposed methods

From abstract to impact in cardiovascular research: factors predicting publication and citation

Aims Through a 4-year follow-up of the abstracts submitted to the European Society of Cardiology Congress in 2006, we aimed at identifying factors predicting high-quality research, appraising the quality of the peer review and editorial processes, and thereby revealing potential ways to improve future research, peer review, and editorial work. Methods and results All abstracts submitted in 2006 were assessed for acceptance, presentation format, and average reviewer rating. Accepted and rejected studies were followed for 4 years. Multivariate regression analyses of a representative selection of 10% of all abstracts (n= 1002) were performed to identify factors predicting acceptance, subsequent publication, and citation. A total of 10 020 abstracts were submitted, 3104 (31%) were accepted for poster, and 701 (7%) for oral presentation. At Congress level, basic research, a patient number ≥ 100, and prospective study design were identified as independent predictors of acceptance. These factors differed from those predicting full-text publication, which included academic affiliation. The single parameter predicting frequent citation was study design with randomized controlled trials reaching the highest citation rates. The publication rate of accepted studies was 38%, whereas only 24% of rejected studies were published. Among published studies, those accepted at the Congress received higher citation rates than rejected ones. Conclusions Research of high quality was determined by study design and largely identified at Congress level through blinded peer review. The scientometric follow-up revealed a marked disparity between predictors of full-text publication and those predicting citation or acceptance at the Congres

Liver transplant outcomes after ex vivo machine perfusion: a meta-analysis

Background: The pressure on liver-transplant programmes has expanded the usage of extended-criteria allografts. Machine perfusion may be better than conventional static cold storage (SCS) in alleviating ischaemia-reperfusion injury in this setting. Recipient outcomes with hypothermic or normothermic machine perfusion were assessed against SCS here. Methods: A search in MEDLINE, EMBASE and Scopus was conducted in February 2021. Primary studies investigating ex vivo machine perfusion were assessed for the following outcomes: morbidity, ICU and hospital stay, graft and patient survival rates and relative costs. Meta-analysis was performed to obtain pooled summary measures. Results: Thirty-four articles involving 1742 patients were included, of which 20 were used for quantitative synthesis. Odds ratios favoured hypothermic machine perfusion (over SCS) with less early allograft dysfunction, ischaemic cholangiopathy, non-anastomotic strictures and graft loss. Hypothermic machine perfusion was associated with a shorter hospital stay and normothermic machine perfusion with reduced graft injury. Two randomized clinical trials found normothermic machine perfusion reduced major complication risks. Conclusion: Machine perfusion assists some outcomes with potential cost savings

Pre-Emptive Endoluminal Negative Pressure Therapy at the Anastomotic Site in Minimally Invasive Transthoracic Esophagectomy (the preSPONGE Trial): Study Protocol for a Multicenter Randomized Controlled Trial

Introduction: Anastomotic leakage (AL) accounts for a significant proportion of morbidity following oesophagectomy. Endoluminal negative pressure (ENP) therapy via a specifically designed polyurethane foam (EsoSponge®, B.Braun Medical, Melsungen, Germany) has become the standard of care for AL in many specialized centres. The prophylactic (pENP) application of this technique aims to reduce postoperative morbidity and is a novel approach which has not yet been investigated in a prospective study. The aim of this study is therefore to assess the effect of pENP at the anastomotic site in high-risk patients undergoing minimally invasive transthoracic Ivor Lewis oesophagectomy. Methods and analysis: The study design is a prospective, multi-centre, two-arm, parallel-group, randomised controlled trial and will be conducted in two phases. Phase one is a randomised feasibility and safety pilot trial involving 40 consecutive patients. After definitive sample size calculation, additional patients will be included accordingly during phase two. The primary outcome of the study will be the postoperative length of hospitalization until reaching previously defined “fit for discharge criteria”. Secondary outcomes will include postoperative morbidity, mortality and postoperative AL-rates based on 90-day follow-up. A confirmatory analysis based on intention-to-treat will be performed. Ethics and dissemination: The ethics committee of the University of Zurich approved this study (2019-00562), which has been registered with ClinicalTrials.gov on 14.11.2019 (NCT04162860) and the Swiss National Clinical Trials Portal (SNCTP000003524). The results of the study will be published and presented at appropriate conferences

The combination of MELD score and ICG liver testing predicts length of stay in the ICU and hospital mortality in liver transplant recipients

AbstractBackgroundEarly prediction of outcome would be useful for an optimal intensive care management of liver transplant recipients. Indocyanine green clearance can be measured non-invasively by pulse spectrophometry and is closely related to liver function.MethodsThis study was undertaken to assess the predictive value of a combination of the model of end stage liver disease (MELD) score and early indocyanine plasma disappearance rates (ICG-PDR) for length of stay in the intensive care unit (ICU), length of stay in the hospital and hospital mortality in liver transplant recipients.ResultsFifty consecutive liver transplant recipients were included in this post Hoc single-center study. ICG-PDR was determined within 6 hours after ICU admission. Endpoints were length of stay in the ICU, length of hospital stay and hospital mortality. The combination of a high MELD score (MELD &gt;25) and a low ICG-PDR clearance (ICG-PDR &lt; 20%/minute) predicts a significant longer stay in the ICU (p = 0.004), a significant longer stay in the hospital (p &lt; 0.001) and a hospital mortality of 40% vs. 0% (p = 0.003).ConclusionThe combination of MELD scores and a singular ICG-PDR measurement in the early postoperative phase is an accurate predictor for outcome in liver transplant recipients. This easy-to-assess tool might be valuable for an optimal intensive care management of those patients.</jats:sec

Cosmesis and body image after single-port laparoscopic or conventional laparoscopic cholecystectomy: a multicenter double blinded randomised controlled trial (SPOCC-trial)

BACKGROUND: Emerging attempts have been made to reduce operative trauma and improve cosmetic results of laparoscopic cholecystectomy. There is a trend towards minimizing the number of incisions such as natural transluminal endoscopic surgery (NOTES) and single-port laparoscopic cholecystectomy (SPLC). Many retrospective case series propose excellent cosmesis and reduced pain in SPLC. As the latter has been confirmed in a randomized controlled trial, patient's satisfaction on cosmesis is still controversially debated. METHODS/DESIGN: The SPOCC trial is a prospective, multi-center, double blinded, randomized controlled study comparing SPLC with 4-port conventional laparoscopic cholecystectomy (4PLC) in elective surgery. The hypothesis and primary objective is that patients undergoing SPLC will have a better outcome in cosmesis and body image 12 weeks after surgery. This primary endpoint is assessed using a validated 8-item multiple choice type questionnaire on cosmesis and body image. The secondary endpoint has three entities: the quality of life 12 weeks after surgery assessed by the validated Short-Form-36 Health Survey questionnaire, postoperative pain assessed by a visual analogue scale and the use of analgesics. Operative time, surgeon's experience with SPLC and 4PLC, use of additional ports, conversion to 4PLC or open cholecystectomy, length of stay, costs, time of work as well as intra- and postoperative complications are further aspects of the secondary endpoint. Patients are randomly assigned either to SPLC or to 4PLC. Patients as well as treating physicians, nurses and assessors are blinded until the 7th postoperative day. Sample size calculation performed by estimating a difference of cosmesis of 20% (alpha = 0.05 and beta = 0.90, drop out rate of 10%) resulted in a number of 55 randomized patients per arm. DISCUSSION: The SPOCC-trial is a prospective, multi-center, double-blind, randomized controlled study to assess cosmesis and body image after SPLC

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Management of patients at the hepatopancreatobiliary unit of a London teaching hospital during the COVID-19 pandemic (vol 13, 13432, 2023)

Correction to: Scientific Reports, published online 18 August 2023 The original version of this Article contained an error in the spelling of the author Harriet Louise Walker which was incorrectly given as Louise Walker Harriet. She is a member of the consortium “On behalf of the Royal Free Hospital London HPB team”. The original Article has been corrected