British Society of Gastroenterology guidelines on sedation in gastrointestinal endoscopy.

Over 2.5 million gastrointestinal endoscopic procedures are carried out in the United Kingdom (UK) every year. Procedures are carried out with local anaesthetic r with sedation. Sedation is commonly used for gastrointestinal endoscopy, but the type and amount of sedation administered is influenced by the complexity and nature of the procedure and patient factors. The elective and emergency nature of endoscopy procedures and local resources also have a significant impact on the delivery of sedation. In the UK, the vast majority of sedated procedures are carried out using benzodiazepines, with or without opiates, whereas deeper sedation using propofol or general anaesthetic requires the involvement of an anaesthetic team. Patients undergoing gastrointestinal endoscopy need to have good understanding of the options for sedation, including the option for no sedation and alternatives, balancing the intended aims of the procedure and reducing the risk of complications. These guidelines were commissioned by the British Society of Gastroenterology (BSG) Endoscopy Committee with input from major stakeholders, to provide a detailed update, incorporating recent advances in sedation for gastrointestinal endoscopy.This guideline covers aspects from pre-assessment of the elective 'well' patient to patients with significant comorbidity requiring emergency procedures. Types of sedation are discussed, procedure and room requirements and the recovery period, providing guidance to enhance safety and minimise complications. These guidelines are intended to inform practising clinicians and all staff involved in the delivery of gastrointestinal endoscopy with an expectation that this guideline will be revised in 5-years' time.

Spatiotemporal control of laser intensity through cross-phase modulation.

Spatiotemporal pulse shaping provides control over the trajectory and range of an intensity peak. While this control can enhance laser-based applications, the optical configurations required for shaping the pulse can constrain the transverse or temporal profile, duration, or orbital angular momentum (OAM). Here we present a novel technique for spatiotemporal control that mitigates these constraints by using a "stencil" pulse to spatiotemporally structure a second, primary pulse through cross-phase modulation (XPM) in a Kerr lens. The temporally shaped stencil pulse induces a time-dependent focusing phase within the primary pulse. This technique, the "flying focus X," allows the primary pulse to have any profile or OAM, expanding the flexibility of spatiotemporal pulse shaping for laser-based applications. As an example, simulations show that the flying focus X can deliver an arbitrary-velocity, variable-duration intensity peak with OAM over distances much longer than a Rayleigh range.

Beam Spray Thresholds in ICF-Relevant Plasmas.

Beam spray measurements suggest thresholds that are a factor of ≈2 to 15× less than expected based on the filamentation figure of merit often quoted in the literature. In this moderate-intensity regime, the relevant mechanism is forward stimulated Brillouin scattering. Both weak ion acoustic wave damping and thermal enhancement of ion acoustic waves contribute to the low thresholds. Forward stimulated Brillouin scattering imparts a redshift to the transmitted beam. Regarding the specific possibility of beam spray occurring outside the laser entrance holes of an indirectly driven hohlraum, this shift may be the most concerning feature owing to the high sensitivity of crossed-beam energy transfer to the interacting beam wavelengths in the subsequent overlap region.

Nonlinear spatiotemporal control of laser intensity.

Spatiotemporal control over the intensity of a laser pulse has the potential to enable or revolutionize a wide range of laser-based applications that currently suffer from the poor flexibility offered by conventional optics. Specifically, these optics limit the region of high intensity to the Rayleigh range and provide little to no control over the trajectory of the peak intensity. Here, we introduce a nonlinear technique for spatiotemporal control, the "self-flying focus," that produces an arbitrary trajectory intensity peak that can be sustained for distances comparable to the focal length. The technique combines temporal pulse shaping and the inherent nonlinearity of a medium to customize the time and location at which each temporal slice within the pulse comes to its focus. As an example of its utility, simulations show that the self-flying focus can form a highly uniform, meter-scale plasma suitable for advanced plasma-based accelerators.

Measurement and control of large diameter ionization waves of arbitrary velocity.

Large diameter, flying focus driven ionization waves of arbitrary velocity (IWAV's) were produced by a defocused laser beam in a hydrogen gas jet, and their spatial and temporal electron density characteristics were measured using a novel, spectrally resolved interferometry diagnostic. A simple analytic model predicts the effects of power spectrum non-uniformity on the IWAV trajectory and transverse profile. This model compares well with the measured data and suggests that spectral shaping can be used to customize IWAV behavior and increase controlled propagation of ionization fronts for plasma-photonics applications.

Psychological Factors as Outcome Predictors for Spinal Cord Stimulation.

BACKGROUND AND AIMS: The mechanism of action of spinal cord stimulation (SCS) is poorly understood and the success of treatment can depend on factors beyond the technical aspects of implantation. The aim of this retrospective analysis is the identification of preimplantation psychological values that may predict outcome of SCS treatment. METHODS: The retrospective analysis consisted of data from 83 patients who underwent SCS implantation from 2005 to 2013. Preimplantation evaluation included pain severity, sleep interference and distress each recorded with a numeric rating scale (NRS 0-10), depression and anxiety (Hospital Anxiety and Depression Score-HADS), catastrophizing (Pain Catastrophizing Scale-PCS), and patient's confidence in performing daily activity (Pain Self-Efficacy Questionnaire-PSEQ). RESULTS: A fall in pain score of greater than 50% at one year follow up was the criteria applied to divide patients into two groups. Group A consisted of 39 patients whose pain score fell more than 50% and group B consisted of 44 patients whose pain score fell less than 50% at one year follow up. The median preimplantation pain score was comparable between the two groups. However, the preimplantation scores for sleep interference, HADS-depression, PCS and PSEQ, were significantly worse in group B. Receiver operating characteristic (ROC) curve analysis and univariate regression show that HADS-depression >10 and PSEQ ≤18 are risk factors for failure of SCS treatment, but only sleep interference, assessed with NRS >7 out of 10 was found to be an independent predictor of a less optimal outcome in multiple logistic regression. CONCLUSIONS: Sleep interference appears to be an independent risk factor for unsuccessful SCS therapy.

Influence of high levels of cloud cover on vitamin D effective and erythemal solar UV irradiances.

The solar irradiances for the initiation of vitamin D synthesis (UV(D3)) have been measured concurrently with the amount of cloud cover to investigate the influence of high cloud cover fraction. The cases of 6.5 and more octa cloud cover were considered for five solar zenith angle (SZA) ranges up to 80°. For each of the SZA ranges, the UV(D3) reduced due to the high cloud cover. The average of the ratios of the UV(D3) irradiances on a cloudy day to those on a clear day with the corresponding ozone and SZA are 0.71 for the 6.5-7.5 octa cloud and 0.45 for the more than 7.5 octa cloud ranges. The exposure times necessary to receive 1/3 MED to a horizontal plane were found to increase as the amount of cloud cover increased. For each cloud cover category, the range of values increased with cloud cover and with SZA. This research shows that the current public recommendations on the times of solar UV exposures required to produce adequate vitamin D are inappropriate for situations of more than 6.5 octa cloud.

High-flow nasal oxygen, procedural sedation, and clinical governance.

Procedural sedation for therapeutic and diagnostic procedures can now be achieved through deep sedation techniques that guarantee procedural success. Deep sedation techniques are delivered in a variety of non-theatre environments where the usual levels of anesthetic equipment are not practical or economical. Hypoxic events are particularly frequent, and challenge sedation providers. Traditional low flow nasal or facial oxygen therapy techniques are often insufficient to maintain acceptable oxygen levels and prevent peri-procedural hypoxia. High flow nasal oxygen delivers warm humidified oxygen up to 70 L/min, at oxygen concentrations between 21-100%, and reduces the incidence of hypoxic events. The provision of deep sedation is a complex process, fraught with risk, which can challenge even the skilled anesthetist. Therefore, regulatory authorities previously stipulated that anesthesia personnel be present during deep sedation. Changing attitudes by regulatory authorities and practical challenges providing anesthesia specialists have led to the acknowledgement that appropriately trained non-anesthetic staff can safely provide deep sedation. Deep sedation services are increasingly applied to subjects with complex co-morbidities, sometimes excluded for safety reasons from surgery under general anesthesia. The development of deep sedation services, delivered by non-anesthesia personnel, to patients with complex co-morbidities requires that services implement appropriate clinical governance tools to prevent deep sedation being the wild west of anesthesia services. Therefore, whilst high flow nasal oxygen may reduce the incidence of peri-procedural hypoxia, the introduction of clinical governance tools and the systematic introduction of initiatives to improve quality, will maintain the safety of deep sedation services.

On the trails of markers and proxies: the socio-cognitive technologies of human movement, knowledge assemblage, and their relevance to the etiology of nasopharyngeal carcinoma.

Bacteria, pigs, rats, pots, plants, words, bones, stones, earrings, diseases, and genetic indicators of all varieties are markers and proxies for the complexity of interweaving trails and stories integral to understanding human movement and knowledge assemblage in Southeast Asia and around the world. Understanding human movement and knowledge assemblage is central to comprehending the genetic basis of disease, especially of a cancer like nasopharyngeal carcinoma. The problem is that the markers and trails, taken in isolation, do not all tell the same story. Human movement and knowledge assemblage are in constant interaction in an adaptive process of co-production with genes, terrain, climate, sea level changes, kinship relations, diet, materials, food and transport technologies, social and cognitive technologies, and knowledge strategies and transmission. Nasopharyngeal carcinoma is the outcome of an adaptive process involving physical, social, and genetic components.

Anesthetic management of peripartum cardiomyopathy.

INTRODUCTION: Peripartum cardiomyopathy (PPCM) is a rare idiopathic cardiomyopathy frequently presenting with heart failure secondary to left ventricular systolic dysfunction towards the end of pregnancy or in the months following delivery. Within the published literature, there are case reports extolling the safety of both regional and general anesthetic interventions in PPCM. However, there is an absence of high-quality evidence to define a suitable paradigm for peri-operative care. In the absence of a large prospective case series or clinical trials, the synthesis of clinical data from published case reports provides an opportunity to distil published clinical data and explore the effect of clinical interventions. EVIDENCE ACQUISITION: A systematic search of English articles English language case reports published between 1986 and 2020 within multiple databases. Clinical data was extracted and aggregated into a database for analysis. EVIDENCE SYNTHESIS: Gestational hypertension and pre-eclampsia were pre-partum risk factors. 403 case reports provided 466 individual cases from 48 countries. Neither regional nor general anesthetic interventions in the peripartum period have a discernible impact on the outcome of patients with PPCM. Rapid unpredictable deterioration in the peripartum period, requiring mechanical cardiac support or heart transplantation is described. The mortality of PPCM is 5-6%. CONCLUSIONS: Patients with PPCM are at risk of rapid unpredictable decline. Management within specialist centers should be considered. Although the data is unsuitable to provide a comprehensive paradigm for the anesthetic and critical care management of PPCM, the observations provide a direction for future clinical audits and trials.

Solar ultraviolet protection provided by human head hair.

The solar erythemal UV irradiances through human hair and the protection from UV provided by human head hair have been investigated for a solar zenith angle (SZA) range of 17-51 degrees for the conditions of a head upright in full sun, a head upright in shade and a head in full sun tilted toward the sun. The two hair lengths investigated were 49.1 +/- 7.1 mm for the short type and 109.5 +/- 5.5 mm for the long type. For the head upright in full sun, the irradiances through the hair ranged from 0.75 to 1.4 SED h(-1) for SZA <25 degrees and <0.6 SED h(-1) in shade. The ultraviolet protection factor (UPF) ranged from approximately 5 to 17 in full sun, with the UPF increasing with higher SZA. The longer hair provided a lower UPF than the shorter hair and for the head oriented toward the sun, there was a marginally lower UPF than for the upright head. This research shows that the UV exposure limits to the scalp through hair can be exceeded within short timeframes and provides important information to assist employers to comply with Workplace Health and Safety legislation.

Deep sedation and anaesthesia in complex gastrointestinal endoscopy: a joint position statement endorsed by the British Society of Gastroenterology (BSG), Joint Advisory Group (JAG) and Royal College of Anaesthetists (RCoA).

In the UK, more than 2.5 million endoscopic procedures are carried out each year. Most are performed under conscious sedation with benzodiazepines and opioids administered by the endoscopist. However, in prolonged and complex procedures, this form of sedation may provide inadequate patient comfort or result in oversedation. As a result, this may have a negative impact on procedural success and patient outcome. In addition, there have been safety concerns on the high doses of benzodiazepines and opioids used particularly in prolonged and complex procedures such as endoscopic retrograde cholangiopancreatography. Diagnostic and therapeutic endoscopy has evolved rapidly over the past 5 years with advances in technical skills and equipment allowing interventions and procedural capabilities that are moving closer to minimally invasive endoscopic surgery. It is vital that safe and appropriate sedation practices follow the inevitable expansion of this portfolio to accommodate safe and high-quality clinical outcomes. This position statement outlines the current use of sedation in the UK and highlights the role for anaesthetist-led deep sedation practice with a focus on propofol sedation although the choice of sedative or anaesthetic agent is ultimately the choice of the anaesthetist. It outlines the indication for deep sedation and anaesthesia, patient selection and assessment and procedural details. It considers the setup for a deep sedation and anaesthesia list, including the equipment required, the environment, staffing and monitoring requirements. Considerations for different endoscopic procedures in both emergency and elective setting are also detailed. The role for training, audit, compliance and future developments are discussed.

Optimizing solar UV-radiation exposures for vitamin D3: comparing global and diffuse spectral UV radiation.

Currently, there is a major gap in the knowledge that is needed to optimize the beneficial effects related to ultraviolet (UV) radiation at wavelengths that induce vitamin D(3) synthesis (UV(D3)) compared to reducing the biologically damaging overexposure to UV radiation. The aim of this study was to investigate the use of diffuse (radiation that is scattered from all directions) UV radiation to optimize exposures to UV(D3) radiation and maximize the reduction of exposure to UVA radiation. Data on global and diffuse solar UV-radiation spectra were collected at 10-min intervals in the Southern Hemisphere in the late spring and summer from 1 November 2006 to 28 February 2007. For a solar zenith angle (SZA) of approximately 5 degrees , the observed maximum UV(D3) irradiances were 0.80 W/m(2) and 0.46 W/m(2) for global and diffuse UV radiation, respectively. The observed maximum UVA irradiances were 79.0 W/m(2) and 36.2 W/m(2) for global and diffuse UV radiation, respectively. For diffuse UV radiation, the maximum ratio of vitamin D(3) to UVA radiation was 1.75% at a SZA of approximately 10 degrees , whereas the maximum ratio for global UV was 1.27% at 10 degrees . For SZAs of 25 degrees and less, more UV radiation is in the wavelength region contributing to vitamin D(3) synthesis (UV(D3)) than in the UVA region for diffuse UV radiation than for global UV radiation.

Paradigm shift: should the elderly undergo propofol sedation for DBE? A prospective cohort study.

OBJECTIVE: Evaluate the safety of propofol-assisted double balloon enteroscopy (DBE) in elderly patients against a younger cohort. DESIGN: Prospective cohort study. SETTING: All patients undergoing DBE over a 30-month period were recruited at our tertiary centre. PATIENTS: 215 procedures in 161 patients were performed. An age cut-off of 65 years and above was used to define those who were elderly. INTERVENTIONS: Patients were subcategorised into four groups: elderly or young undergoing DBE with propofol or conventional sedation (with midazolam±fentanyl). MAIN OUTCOME MEASURES: Patient demographics, comorbidities, procedural data, complications, diagnostic and therapeutic yield were compared. RESULTS: Cardiovascular disease and a higher American Society of Anaethesiologists (ASA) status were more prevalent in elderly patients undergoing DBE with propofol (p<0.05). Common indications for DBE were occult and overt obscure gastrointestinal bleeding and suspected Crohn's disease (elderly vs young: 50.7% vs 42.3%, 17.8% vs 12% and 19.2% vs 26.1%, respectively). Diagnostic yield was higher in elderly compared with young patients (75.3% vs 58.5%, p=0.016). The most common findings in elderly and young patients were angioectasia (30.1% and. 18.3%, respectively) and ulcers (17.8% and 9.2%, respectively), while therapeutic intervention rates were comparable (42.5% vs 32.4%, p=0.18). ASA status did not affect propofol dose (p=0.55) or procedure duration (p=0.31). Tolerance scores were favourable in those receiving propofol compared with conventional sedation (p<0.05). There was no difference in complications between the four groups (p=0.17). CONCLUSION: Compared with young patients, propofol-assisted DBE in the elderly is safe and has a high diagnostic yield.

Evaluation of a high exposure solar UV dosimeter for underwater use.

Solar ultraviolet radiation (UV) is known to have a significant effect upon the marine ecosystem. This has been documented by many previous studies using a variety of measurement methods in aquatic environments such as oceans, streams and lakes. Evidence gathered from these investigations has shown that UVB radiation (280-320 nm) can negatively affect numerous aquatic life forms, while UVA radiation (320-400 nm) can both damage and possibly even repair certain types of underwater life. Chemical dosimeters such as polysulphone have been tested to record underwater UV exposures and in turn quantify the relationship between water column depth and dissolved organic carbon levels to the distribution of biologically damaging UV underwater. However, these studies have only been able to intercept UV exposures over relatively short time intervals. This paper reports on the evaluation of a high exposure UV dosimeter for underwater use. The UV dosimeter was fabricated from poly 2,6-dimethyl-1,4-phenylene oxide (PPO) film. This paper presents the dose response, cosine response, exposure additivity and watermarking effect relating to the PPO dosimeter as measured in a controlled underwater environment and will also detail the overnight dark reaction and UVA and visible radiation response of the PPO dosimeter, which can be used for error correction to improve the reliability of the UV data measured by the PPO dosimeters. These results show that this dosimeter has the potential for long-term underwater UV exposure measurements.

Dosimetric and spectroradiometric investigations of glass filtered solar UV.

The aims of this paper were to investigate how glass-filtered UV irradiances vary with glass thickness, lamination of the glass and the effect of solar zenith angle (SZA), and to measure the glass-filtered UV exposures to different receiving planes with a newly developed UVA dosimeter. Spectroradiometric and dosimetric techniques were employed in the experimental approach. The percentage of the glass-filtered solar UV compared to the unfiltered UV ranged from 59% to 70% and was influenced to a small extent by the glass thickness and the SZA. The laminated glass transmitted 11 to 12% and the windscreen glass transmitted 2.5-2.6%. The influence of the SZA was less for the thicker glass than it was for the thinner glass. The change in transmission was less than 14% for the SZA between 48 degrees and 71 degrees. There was negligible influence due to the SZA on the glass-transmitted UV of the laminated and windscreen glass. The influence of the glass thickness in the range of 2-6 mm on the percentage transmission was less than 16%. The influences of the glass thickness and the SZA on the glass-transmitted UV have been incorporated in the use of a UVA dosimeter for the glass-transmitted UV exposures. The UVA dosimeter was employed in the field to measure the glass-filtered UV exposures to different receiving planes. The UVA dosimeter reported has the potential for personal solar UVA exposure measurements.