Efficient assembly of multi-color fiberless optoelectrodes with on-board light sources for neural stimulation and recording

Fiberless optoelectrodes are an emerging tool to enable brain circuit mapping by providing precise optical modulation and electrical monitoring of many neurons. While optoelectrodes having an on-board light source offer compact and optically efficient device solutions, many of them fail to provide robust thermal and electrical design to fully exploit the recording capabilities of the device. In this work, we present a novel fiberless multicolor optoelectrode solution, which meets the optical and thermal design requirements of an in vivo neural optoelectrode and offers potential for low-noise neural recording. The total optical loss measured for 405 nm and 635 nm wavelengths through the waveguide is 11.7±1.1 dB and 9.9±0.7 dB, corresponding to respective irradiances of 1928 mW/mm2 and 2905 mW/mm2 at the waveguide tip from 6 mW laser diode chips. The efficient thermal packaging enables continuous device operation for up to 190 seconds at 10% duty cycle. We validated the fully packaged device in the intact brain of anesthetized mice co-expressing Channelrhodopsin-2 and Archaerhodopsin in the hippocampal CA1 region and achieved activation and silencing of the same neurons. We discuss improvements made to reduce the stimulation artifact induced by applying currents to the laser diode chips.

Challenges and outcomes of a randomized study of early nutrition support during autologous stem-cell transplantation

Patients undergoing myeloablative conditioning regimens and autologous stem-cell transplantation (asct) are at high risk of malnutrition. This randomized study aimed to determine if early nutrition support (commenced when oral intake is less than 80% of estimated requirements) compared with usual care (commenced when oral intake is less than 50% of estimated requirements) reduces weight loss in well-nourished patients undergoing high-nutritional-risk conditioning chemotherapy and asct. In the 50 well-nourished patients who were randomized, the outcomes evaluated included changes in weight and lean body mass (mid-upper arm circumference), length of stay, time to hemopoietic engraftment, and quality of life (Memorial Symptom Assessment Scale - Short Form). On secondary analysis, after exclusion of a single extreme outlier, both groups demonstrated significant weight loss over time (p = 0.0005). Weight loss was less in the early nutrition support group at time of discharge (mean: -0.4% ± 2.9% vs. -3.4% ± 2.6% in the usual care group, p = 0.001). This difference in weight was no longer observed at 6 months after discharge (mean: -1.0% ± 6.8% vs. 1.4% ± 6.1%, p = 0.29). In practice, an early start to nutrition support proved difficult because of patient resistance and physician preference, with 8 patients (33%) in the control group and 4 (15%) in the intervention group not commencing nutrition support when stipulated by the study protocol. No significant differences between the groups were found for other outcomes. In well-nourished patients receiving asct, early nutrition support maintained weight during admission, but did not affect other outcomes. Interpretation of results should take into consideration the difficulties encountered with intervention implementation.

Transitions to palliative care for older people in acute hospitals: a mixed-methods study

Background

Improving the provision of palliative and end-of-life care is a priority for the NHS. Ensuring an appropriately managed ‘transition’ to a palliative approach for care when patients are likely to be entering the last year of life is central to current policy. Acute hospitals represent a significant site of palliative care delivery and specific guidance has been published regarding the management of palliative care transitions within this setting.

Aims

(1) to explore how transitions to a palliative care approach are managed and experienced in acute hospitals and to identify best practice from the perspective of clinicians and service users; (2) to examine the extent of potentially avoidable hospital admissions amongst hospital inpatients with palliative care needs.

Design

A mixed-methods design was adopted in two hospitals in England, serving diverse patient populations. Methods included (1) two systematic reviews; (2) focus groups and interviews with 58 health-care professionals to explore barriers to, and facilitators of, palliative care transitions in hospital; (3) a hospital inpatient survey examining palliative care needs and aspects of management including a self-/proxy-completed questionnaire, a survey of medical and nursing staff and a case note review; (4) in-depth interviews with 15 patients with palliative care needs; (5) a retrospective case note review of all inpatients present in the hospital at the time of the survey who had died within the subsequent 12 months; and (6) focus groups with 83 key decision-makers to explore the implications of the findings for service delivery and policy.

Results

Of the 514 patients in the inpatient survey sample, just over one-third (n = 185, 36.0%) met one or more of the Gold Standards Framework (GSF) prognostic indicator criteria for palliative care needs. The most common GSF prognostic indicator was frailty, with almost one-third of patients (27%) meeting this criteria. Agreement between medical and nursing staff and the GSF with respect to identifying patients with palliative care needs was poor. In focus groups, health professionals reported difficulties in recognising that a patient had entered the last 12 months of life. In-depth interviews with patients found that many of those interviewed were unaware of their prognosis and showed little insight into what they could expect from the trajectory of their disease. The retrospective case note review found that 35 (7.2%) admissions were potentially avoidable. The potential annual cost saving across both hospitals of preventing these admissions was approximately £5.3M. However, a 2- or 3-day reduction in length of stay for these admissions would result in an annual cost saving of £21.6M or £32.4M respectively.

Conclusions

Patients with palliative care needs represent a significant proportion of the hospital inpatient population. There is a significant gap between NHS policy regarding palliative and end-of-life care management in acute hospitals in England and current practice.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.