Factors Affecting Blood Loss In Liver Surgery For Colorectal Metastases

Introduction Peri-operative blood loss and blood transfusions are associated with poorer short- and long-term outcomes in patients undergoing hepatectomy. Various techniques are utilised to decrease blood loss though these may also cause an Ischaemia-Reperfusion Injury (IRI). The aim of this thesis was to identify factors which predispose to intra-operative bleeding during liver surgery and to identify methods to decrease blood loss without increasing the likelihood of post-operative liver dysfunction Methods In order to address the aim of this thesis, several studies are performed: 1. A systematic review examining non-surgical methods to decrease blood loss. Primary outcome measures included peri-operative blood loss and transfusion requirements. The secondary outcome measure was occurrence of IRI. The review was performed according to the PRISMA guidelines for systematic reviews. 2. A retrospective database analysed the association between blood transfusion and survival. . Uni- and multivariate analysis were performed. 3. A pilot single blinded, randomised control trial (RCT) was undertaken comparing the Pringle manoeuvre (standard) versus Portal Vein clamping. Results 1. Seventeen studies were included in the systematic review. In 8 studies (n=894) pharmacological methods and in another 9 studies (n=679) anaesthetic methods to decrease blood loss were investigated. In 3 trials potential benefits of anti-fibrinolytics were demonstrated. Six anaesthetic trials demonstrated potential roles for low central venous pressure, acute normovolaemic haemodilution, autologous blood donation techniques and choice of inhalational anaesthetic agent employed. 2. Six hundred and ninety patients were included in this study. Median follow-up was 33 months. Sixty-four (9.3%) patients required a peri-operative RBCT. Red cell transfusion was a predictor for decreased OS (median 41 vs 49 months, p=0.04). However, on multivariate regression analyses pre-operative chemotherapy, post-operative complications and Clinical Risk Score (CRS) were independently associated with reduced overall survival, though RBCT was not. There was no association between RBCT and recurrence free survival ( median 15 vs 17 months, p=0.28) 3. The main findings of the RCT were that it was technically feasible to perform isolated portal vein clamping in patients and to recruit patients into the trial. However, a larger RCT will be needed to obtain definitive evidence on the role of PVC in hepatic resections in the future Conclusions There is potential for use of non-surgical techniques to decrease peri-operative bleeding in liver surgery. RBCT is not independently associated with poorer survival although it may be a surrogate marker for more advanced disease. The RCT confirms that isolated portal vein clamping is technically feasible and it was possible to recruit into the trial; a multi-centre RCT is required to assess the role of isolated portal vein clamping surgery for colorectal liver metastases

Surface-Enhanced Raman Scattering: Introduction and Applications

Scattering of light by molecules can be elastic, Rayleigh scattering, or inelastic, Raman scattering. In the elastic scattering, the photon’s energy and the state of the molecule after the scattering events are unchanged. Hence, Rayleigh scattered light does not contain much information on the structure of molecular states. In inelastic scattering, the frequency of monochromatic light changes upon interaction with the vibrational states, or modes, of a molecule. With the advancement in the laser sources, better and compact spectrometers, detectors, and optics Raman spectroscopy have developed as a highly sensitive technique to probe structural details of a complex molecular structure. However, the low scattering cross section (10−31) of Raman scattering has limited the applications of the conventional Raman spectroscopy. With the discovery of surface-enhanced Raman scattering (SERS) in 1973 by Martin Fleischmann, the interest of the research community in Raman spectroscopy as an analytical method has been revived. This chapter aims to familiarize the readers with the basics of Raman scattering phenomenon and SERS. This chapter will also discuss the latest developments in the SERS and its applications in various fields

Appraisal of Noise Level Dissemination Surrounding Mining and Industrial Areas of Keonjhar, Odisha: a Comprehensive Approach Using Noise Mapping

Noise mapping is a well-established practice among the European nations, and it has been following for almost two decades. Recently, as per guidelines of the Directorate General of Mines Safety (DGMS), India, noise mapping has made mandatory in the mining expanses. This study is an effort made to map the noise levels in nearby areas of mines in the northern Keonjhar district. The motive of this study is to quantify the existing A-weighted time-average sound level (LAeq,T) in the study area to probe its effects on the human dwellings and noise sensitive areas with the probability of future development of the mines, roads and industrial & commercial zone. The LAeq,T was measured at 39 identified locations, includes industrial, commercial, residential and sensitive zones, 15 open cast mines, 3 major highways and 3 haulage roads. With the utilization of Predictor LimA Software and other GIS tools, the worked out data is mapped and noise contours are developed for the visualization and identification of the extent and distribution of sound levels across the study area. This investigation discloses that the present noise level at 60% of the locations in silence and residential zone are exposed to significantly high noise levels surpasses the prescribed limit of Central Pollution Control Board (CPCB), India. The observed day and night time LAeq,T level of both the zone, ranged between 43.2 - 62.2 dB (A) and 30.5 – 53.4 dB (A) respectively whereas, the average Ldn values vary between 32.7 – 51.2 dB (A). The extensive mobility of heavy vehicles adjoining the sensitive areas and a nearby plethora of open cast mines is the leading cause of exceeded noise levels. The study divulges that the delicate establishments like school and hospitals are susceptible to high noise levels throughout the day and night. A correlation between observed and software predicted values gives R2 of 0.605 for Ld; 0.217 for Ln; and 0.524 for Ldn. Finally, the mitigation measure proposed and demonstrated using contour map showing a significant reduction in the noise levels by 0 – 5.3 dB (A)

Evaluation and Forecasting of Highway Traffic Noise in the city of Nagpur, India

The noise levels in Indian cities are largely affected due to increase in the number of vehicles and growth of the transportation sector in the past few years. Transportation is crucial owing to Nagpur’s strategic location in central India. The City is linked with four metros Viz. Mumbai, Delhi, Kolkata and Chennai through roads, rails, and air. It’s also a major conjugation for roadways as India's two national highways, Hajira-Kolkata (NH-06) and Kanyakumari-Varanasi (NH-07) are passing through the city. The main objective of this study is to assess and predict the traffic noise levels of uninterrupted traffic flow on prominent highways, and an attempt has been made to develop noise maps to represent an overall noise scenario of the city. Noise modelling and prediction are performed using a modified Federal Highway Administration (FHWA) model. Substantial correlation has been obtained between the measured and estimated noise levels, which gives R2 of 0.503 having an error band of ± 3.8% with respect to the observed noise levels. Octave band spectral analysis reveals the dominance of noise emission levels in the medium and high-frequency range. This study perceives the observed equivalent noise levels at all the locations during the day and night hours exceeds up to 7.8 dB and 19.6 dB respectively, when compared with the permissible limits prescribed by National standard and signifies that the FHWA model is suitable for Indian road traffic conditions

Making large scale surgical trials possible:collaboration and the role of surgical trainees

Abstract Background Recruitment to surgical randomised controlled trials (RCTs) can be challenging. The Sunflower study is a large-scale multi-centre RCT that seeks to establish the clinical and cost effectiveness of pre-operative imaging versus expectant management in patients with symptomatic gallstones undergoing laparoscopic cholecystectomy at low or moderate risk of common bile duct stones. Trials such as Sunflower, with a large recruitment target, rely on teamworking. Recruitment can be optimised by embedding a QuinteT Recruitment Intervention (QRI). Additionally, engaging surgical trainees can contribute to successful recruitment, and the NIHR Associate Principal Investigator (API) scheme provides a framework to acknowledge their contributions. Methods This was a mixed-methods study that formed a component part of an embedded QRI for the Sunflower RCT. The aim of this study was to understand factors that supported and hindered the participation of surgical trainees in a large-scale RCT and their participation in the API scheme. It comprised semi-structured telephone interviews with consultant surgeons and surgical trainees involved in screening and recruitment of patients, and descriptive analysis of screening and recruitment data. Interviews were analysed thematically to explore the perspectives of—and roles undertaken by—surgical trainees. Results Interviews were undertaken with 34 clinicians (17 consultant surgeons, 17 surgical trainees) from 22 UK hospital trusts. Surgical trainees contributed to patient screening, approaches and randomisation, with a major contribution to the randomisation of patients from acute admissions. They were often encouraged to participate in the study by their centre principal investigator, and career development was a typical motivating factor for their participation in the study. The study was registered with the API scheme, and a majority of the trainees interviewed (n = 14) were participating in the scheme. Conclusion Surgical trainees can contribute substantial activity to a large-scale multi-centre RCT. Benefits of trainee engagement were identified for trainees themselves, for local sites and for the study as a whole. The API scheme provided a formal framework to acknowledge engagement. Ensuring that training and support for trainees are provided by the trial team is key to optimise success for all stakeholders

Evaluation of an Electricity-free, Culture-based Approach for Detecting Typhoidal Salmonella Bacteremia during Enteric Fever in a High Burden, Resource-limited Setting

Background: In many rural areas at risk for enteric fever, there are few data on Salmonella enterica serotypes Typhi (S. Typhi) and Paratyphi (S. Paratyphi) incidence, due to limited laboratory capacity for microbiologic culture. Here, we describe an approach that permits recovery of the causative agents of enteric fever in such settings. This approach involves the use of an electricity-free incubator based upon use of phase-change materials. We compared this against conventional blood culture for detection of typhoidal Salmonella. Methodology/Principal Findings: Three hundred and four patients with undifferentiated fever attending the outpatient and emergency departments of a public hospital in the Kathmandu Valley of Nepal were recruited. Conventional blood culture was compared against an electricity-free culture approach. Blood from 66 (21.7%) patients tested positive for a Gram-negative bacterium by at least one of the two methods. Sixty-five (21.4%) patients tested blood culture positive for S. Typhi (30; 9.9%) or S. Paratyphi A (35; 11.5%). From the 65 individuals with culture-confirmed enteric fever, 55 (84.6%) were identified by the conventional blood culture and 60 (92.3%) were identified by the experimental method. Median time-to-positivity was 2 days for both procedures. The experimental approach was falsely positive due to probable skin contaminants in 2 of 239 individuals (0.8%). The percentages of positive and negative agreement for diagnosis of enteric fever were 90.9% (95% CI: 80.0%–97.0%) and 96.0% (92.7%–98.1%), respectively. After initial incubation, Salmonella isolates could be readily recovered from blood culture bottles maintained at room temperature for six months. Conclusions/Significance: A simple culture approach based upon a phase-change incubator can be used to isolate agents of enteric fever. This approach could be used as a surveillance tool to assess incidence and drug resistance of the etiologic agents of enteric fever in settings without reliable local access to electricity or local diagnostic microbiology laboratories.Boston Children's Hospital (Frederick H. Lovejoy Fund)Harvard Global Health InstituteNational Institute of Allergy and Infectious Diseases (U.S.) (Grant AI100023)National Institute of Allergy and Infectious Diseases (U.S.) (Grant AI077883