Review on the development of truly portable and in-situ capillary electrophoresis systems

Capillary electrophoresis (CE) is a technique which uses an electric field to separate a mixed sample into its constituents. Portable CE systems enable this powerful analysis technique to be used in the field. Many of the challenges for portable systems are similar to those of autonomous in-situ analysis and therefore portable systems may be considered a stepping stone towards autonomous in-situ analysis. CE is widely used for biological and chemical analysis and example applications include: water quality analysis; drug development and quality control; proteomics and DNA analysis; counter-terrorism (explosive material identification) and corrosion monitoring. The technique is often limited to laboratory use, since it requires large electric fields, sensitive detection systems and fluidic control systems. All of these place restrictions in terms of: size, weight, cost, choice of operating solutions, choice of fabrication materials, electrical power and lifetime. In this review we bring together and critique the work by researchers addressing these issues. We emphasize the importance of a holistic approach for portable and in-situ CE systems and discuss all the aspects of the design. We identify gaps in the literature which require attention for the realization of both truly portable and in-situ CE systems

Randomised, controlled trial of alternating pressure mattresses compared with alternating pressure overlays for the prevention of pressure ulcers : PRESSURE (pressure relieving support surfaces) trial

Objective To compare whether differences exist between alternating pressure overlays and alternating pressure mattresses in the development of new pressure ulcers, healing of existing pressure ulcers, and patient acceptability. Design Pragmatic, open, multicentre, randomised controlled trial. Setting 11 hospitals in six NHS trusts. Participants 1972 people admitted to hospital as acute or elective patients. Interventions Participants were randomised to an alternating pressure mattress (n = 982) of- an alternating pressure overlay (n = 990). Main outcome measures The proportion of participants developing a new pressure ulcer of grade 2 or worse; time to development of new pressure ulcers; proportions of participants developing a new ulcer within 30 days; healing of existing pressure ulcers; and patient acceptability Results Intention to treat analysis found no difference in the proportions of participants developing a new pressure ulcer of grade 2 or worse (10.7% overlay patients, 10.3% mattress patients; difference 0.4%, 95% confidence interval - 23% to 3.1%, P = 0.75). More overlay patients requested change owing to dissatisfaction (23.3%) than mattress patients (18.9%, P = 0.02). Conclusion No difference was found between alternating pressure mattresses and alternating pressure overlays in the proportion of people who develop a pressure ulcer

Tattoo Antenna Temporary Transfers Operating On-Skin (TATTOOS)

This paper discusses the development of RFID logo antennas based on the logos of Loughborough University and the University of Kent which can be tattooed directly onto the skin’s surface. Hence, this paper uses aesthetic principles to create functional wearable technology. Simulations of possible designs for the tattoo tags have been carried out to optimize their performance. Prototypes of the tag designs were fabricated and read range measurements with the transfer tattoos on a volunteers arm were carried out to test the performance. Measured Read ranges of approximately 0.5 m have been achieved with the antenna 10 µm from the body

A systematic review of duplex ultrasound, magnetic resonance angiography and computed tomography angiography for the diagnosis and assessment of symptomatic, lower limb peripheral arterial disease.

OBJECTIVES: To determine the diagnostic accuracy and cost-effectiveness of duplex ultrasound (DUS), magnetic resonance angiography (MRA), and computed tomography angiography (CTA), as alternatives to contrast angiography (CA), for the assessment of lower limb peripheral arterial disease (PAD). DATA SOURCES: Ten electronic databases were searched in April 2004, with an update in May 2005. Six key journals and bibliographies of included studies were also searched and experts in the field were consulted. REVIEW METHODS: Data extraction and quality assessment were performed in duplicate. Data were analysed according to test type and diagnostic threshold. For the economic analysis, a decision tree was developed and a probabilistic sensitivity analysis performed to incorporate statistical uncertainty into the cost-effectiveness analysis. RESULTS: A total of 113 studies met the inclusion criteria (including six economic evaluations). For the detection of stenosis greater than 50% in the whole leg, contrast-enhanced (CE) MRA (14 studies) had the highest diagnostic accuracy, with sensitivity ranging from 92 to 99.5% and specificity from 64 to 99%. Two-dimensional (2D) time-of-flight (TOF) MRA (11 studies) was less accurate, with sensitivity ranging from 79 to 94% and specificity from 74 to 92%. 2D phase-contrast (PC) MRA (one study) had a sensitivity of 98% and specificity of 74%. CTA (seven studies) also appeared slightly inferior to CE MRA, with a sensitivity ranging from 89 to 99% and specificity from 83 to 97%, but better than DUS (28 studies), which had a sensitivity ranging from 80 to 98% and specificity from 89 to 99%. There was some indication that CE MRA and DUS were more accurate for detecting stenoses/occlusions above the knee than below the knee or in the pedal artery. The four studies of patient attitudes strongly suggested that patients preferred CE MRA to CA. CA was considered the most uncomfortable test, followed by CE MRA, with CTA being the least uncomfortable. Half of the patients (from a sample who did not suffer from claustrophobia and had no metallic implants) expressed no preference between undergoing TOF MRA or DUS; most of those who did express a preference favoured TOF MRA. In the 55 studies identified for adverse events, MRA was associated with the highest reported proportion. However, the most severe adverse events were more common in patients undergoing CA; although these were rare for both tests. The economic evaluation showed DUS dominated the other alternatives when the whole leg was assessed, by presenting higher effectiveness at a lower cost per quality-adjusted life-year (QALY; i.e. 13,646 pounds per QALY). When the assessment was limited to a section of the leg, either above the knee or below the knee, 2D TOF MRA was the most cost-effective preoperative diagnostic strategy. The incremental cost per QALY for below-the-knee comparisons was equal to 37,024 pounds when 2D TOF MRA was compared with DUS. For above-the-knee comparisons, 2D TOF MRA presented the lowest cost and slightly lower effectiveness compared with CE MRA, with a cost per QALY equal to 13,442 pounds. CONCLUSIONS: The results of the review suggest that CE MRA has a better overall diagnostic accuracy than CTA or DUS, and that CE MRA is generally preferred by patients over CA. Where available, CE MRA may be a viable alternative to CA. The only controlled trial suggested that the results of DUS were comparable to those of CA, in terms of surgical planning and outcome. This finding conflicts with the results of diagnostic accuracy studies, which reported poor estimates of accuracy for DUS in comparison with CA. There was insufficient evidence to evaluate the usefulness of CTA for the assessment of PAD, particularly newer techniques. The results of the economic modelling suggest that for PAD patients for whom the whole leg is evaluated by a preoperative diagnostic test, DUS dominates the other alternatives by presenting higher effectiveness at a lower cost per QALY. However, when the analysis of stenosis is limited to a section of the leg, either above the knee or below the knee, 2D TOF MRA appears to be the most cost-effective preoperative diagnostic strategy. Further research is needed into a number of areas including the relative clinical effectiveness of the available imaging tests, in terms of surgical planning and postoperative outcome

Congenital brachial palsy: incidence, causes, and outcome in the United Kingdom and Republic of Ireland

Objectives: To determine the incidence and study the causes and outcome of congenital brachial palsy (CBP). Design: Active surveillance of newborn infants using the British Paediatric Surveillance Unit notification system and follow up study of outcome at 6 months of age. Setting: The United Kingdom and Republic of Ireland. Participants: Newborn infants presenting with a flaccid paresis of the arm (usually one, rarely both) born between April 1998 and March 1999. Main outcome measures: Extent of the lesion at birth and degree of recovery at 6 months of age. Findings: There were 323 confirmed cases giving an incidence of 0.42 per 1000 live births (1 in 2300). Significant associated risk factors in comparison with the normal population were shoulder dystocia (60% v 0.3%), high birth weight with 53% infants weighing more than the 90th centile, and assisted delivery (relative risk (RR) 3.4, 95% confidence interval (CI) 2.9 to 3.9, p = 0.0001). There was a considerably lower risk of CBP in infants delivered by caesarean section (RR 7, 95% CI 2 to 56, p = 0.002). At about 6 months of age, about half of the infants had recovered fully, but the remainder showed incomplete recovery including 2% with no recovery. The relative risk of partial or no recovery in infants with extensive lesions soon after birth compared with those with less extensive lesions was 11.28 (95% CI 2.38 to 63.66, p = 0.000005). Conclusions: The incidence of CBP in the United Kingdom and Republic of Ireland is strikingly similar to that previously reported nearly 40 years ago. Most cases are due to trauma at delivery, which is not necessarily excessive or inappropriate. Given the uncertainty about the appropriate management of these infants, serious consideration should be given to a formal clinical trial of microsurgical nerve repair

A systematic review and economic model of switching from non-glycopeptide to glycopeptide antibiotic prophylaxis for surgery

OBJECTIVES: To determine whether there is a level of methicillin-resistant Staphylococcus aureus (MRSA) prevalence at which a switch from non-glycopeptide to glycopeptide antibiotics for routine prophylaxis is indicated in surgical environments with a high risk of MRSA infection. DATA SOURCES: Major electronic databases were searched up to September 2005. REVIEW METHODS: The effectiveness review included controlled clinical trials comparing a glycopeptide with an alternative antibiotic regimen that reported effectiveness and/or adverse events. Controlled observational studies were also included for adverse events. The cost-effectiveness review included economic evaluations comparing glycopeptide prophylaxis with any alternative comparator. Study validity was assessed using standard checklists. The supplementary economic reviews assessed evaluations of non-glycopeptide antibiotic prophylaxis; evaluations where antibiotic resistance is a problem; methods of modelling resistance in infectious diseases; and developing a conceptual framework. An indicative decision analytic model was developed to compare vancomycin with a cephalosporin and with a combination of vancomycin and cephalosporin, using hip arthroplasty as an exemplar. Available data on, for example, surgical site infection (SSI) rates, MRSA rates, effectiveness of the antibiotics, were incorporated into the model. Costs were estimated from the perspective of the NHS. RESULTS: The effectiveness review included 16 randomised controlled trials, with a further three studies included for adverse events only. There was no evidence that glycopeptides were more effective than non-glycopeptides in preventing SSIs. Most of the trials did not report either the baseline prevalence of MRSA at the participating surgical units or MRSA infections as an outcome. The cost-effectiveness review included five economic evaluations of glycopeptide prophylaxis. Only one study incorporated health-related quality of life and undertook a cost-utility analysis. None of the studies was undertaken in the UK and none explicitly modelled antibiotic resistance. The supplementary reviews provided few insights into how to assess cost-effectiveness in the context of resistance. No studies modelled cost-effectiveness alongside epidemiological models of resistance. There was little information regarding the impact of surgical infections on costs post-discharge and patient quality of life. The lack of available clinical evidence limited the development of the cost-effectiveness model and meant that the modelling could only be indicative in nature. The model can be used to show the threshold baseline risk at which the use of vancomycin as prophylaxis might be cost-effective (the model did not include teicoplanin). The indicative model suggests that the baseline risk of MRSA can be fairly modest at below the national average and it would still appear cost-effective to use glycopeptide prophylaxis. The model indicates that the use of glycopeptides as a form of prophylaxis in addition to a treatment for MRSA infections is unlikely to decrease the total usage and hence reduce the risk of future problems with glycopeptide-resistant bacteria. CONCLUSIONS: There is insufficient evidence to determine whether there is a threshold prevalence of MRSA at which switching from non-glycopeptide to glycopeptide antibiotic prophylaxis might be clinically effective and cost-effective. Future research needs to address the complexities of decision-making relating to the prevention of MRSA and infection control in general. Research including evidence synthesis and decision modelling comparing a full range of interventions for infection control, which extends to other infections, not just MRSA, is needed. A long-term research programme to predict the pattern of drug resistance and its implications for future costs and health is also needed