Stakeholder Perspectives of Attributes and Features of Context Relevant to Knowledge Translation in Health Settings: A Multi-Country Analysis

BACKGROUND

Context is recognized as important to successful knowledge translation (KT) in health settings. What is meant by context, however, is poorly understood. The purpose of the current study was to elicit tacit knowledge about what is perceived to constitute context by conducting interviews with a variety of health system stakeholders internationally so as to compile a comprehensive list of contextual attributes and their features relevant to KT in healthcare.

METHODS

A descriptive qualitative study design was used. Semi-structured interviews were conducted with health system stakeholders (change agents/KT specialists and KT researchers) in four countries: Australia, Canada, the United Kingdom, and the United States. Interview transcripts were analyzed using inductive thematic content analysis in four steps: (1) selection of utterances describing context, (2) coding of features of context, (3) categorizing of features into attributes of context, (4) comparison of attributes and features by: country, KT experience, and role.

RESULTS

A total of 39 interviews were conducted. We identified 66 unique features of context, categorized into 16 attributes. One attribute, Facility Characteristics, was not represented in previously published KT frameworks. We found instances of all 16 attributes in the interviews irrespective of country, level of experience with KT, and primary role (change agent/KT specialist vs. KT researcher), revealing robustness and transferability of the attributes identified. We also identified 30 new context features (across 13 of the 16 attributes).

CONCLUSION

The findings from this study represent an important advancement in the KT field; we provide much needed conceptual clarity in context, which is essential to the development of common assessment tools to measure context to determine which context attributes and features are more or less important in different contexts for improving KT success.

Children With Medical Complexity in the Canadian Maritimes: Protocol for a Mixed Methods Study

BACKGROUND

Ongoing developments in the medical field have improved survival rates and long-term management of children with complex chronic health conditions. While the number of children with medical complexity is small, they use a significant amount of health resources across various health settings and sectors. Research to date exploring this pediatric population has relied primarily on quantitative or qualitative data alone, leaving significant gaps in our understanding of this population.

OBJECTIVE

The objective of this research is to use health administrative and family-reported data to gain an in-depth understanding of patterns of health resource use and health care needs of children with medical complexity and their families in the Canadian Maritimes.

METHODS

An explanatory sequential mixed methods design will be used to achieve our research objective. Phase 1 of this research will leverage the use of health administrative data to examine the prevalence and health service use of children with medical complexity. Phase 2 will use case study methods to collect multiple sources of family-reported data to generate a greater understanding of their experiences, health resource use, and health care needs. Two cases will be developed in each of the 3 provinces. Cases will be developed through semistructured interviews with families and their health care providers and health resource journaling. Findings will be triangulated from phase 1 and 2 using a joint display table to visually depict the convergence and divergence between the quantitative and qualitative findings. This triangulation will result in a comprehensive and in-depth understanding into the population of children with medical complexity.

RESULTS

This study will be completed in May 2022. Findings from each phase of the research and integration of the two will be reported in full in 2022.

CONCLUSIONS

There is a current disconnect between the Canadian health care system and the needs of children with medical complexity and their families. By combining health administrative and family-reported data, this study will unveil critical information about children with medical complexity and their families to more efficiently and effectively meet their health care needs. Results from this research will be the first step in designing patient-oriented health policies and programs to improve the health care experiences, health system use, and health outcomes of children with medical complexity and their families.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/33426.

Improving transitions in care for children with complex and medically fragile needs: a mixed methods study

Background

Children with medical complexity are a small yet resource intensive population in the Canadian health care system. The process for discharging these children from hospital to home is not yet optimal. The overall goal of this project was to develop recommendations to be included in a provincial strategy to support transitions in care for children with complex and medically fragile needs.

Methods

A wide assortment of stakeholders participated in this mixed method, multiphase project. During Phase 1, data was gathered from a range of sources to document families’ experiences transitioning from an inpatient hospital stay back to their home communities. In Phase 2, pediatricians, nurses, and health administrators participated in key stakeholder interviews to identify barriers and facilitators to a successful transition in care for children and families with complex care needs. A multi-sector consensus meeting was held during Phase 3 to discuss study findings and refine key recommendations for inclusion in a provincial strategy.

Results

Six case studies were developed involving children and families discharged home with a variety of complex care needs. Children ranged in age from 15 days to 9 years old. Nine telephone interviews were conducted in Phase 2 with pediatricians, nurses, and administrators from across the province. A variety of inter-institutional communication challenges were described as a major barrier to the transition process. A consistent message across all interviews was the need for improved coordination to facilitate transitions in care. The consensus meeting to review study findings included physicians, nurses, paramedics, senior administrators, and policy analysts from different health and government sectors and resulted in six recommendations for inclusion in a provincial strategy.

Conclusions

This project identified policy and practice gaps that currently exist related to transitions in care for children with complex and medically fragile needs and their families. Our collaborative patient-centred approach to understanding how children and families currently navigate transitions in care provided a foundation for developing recommendations for a provincial wide strategy.

Experiences With Managing the Workplace Social Environment: A Qualitative Study

OBJECTIVE

This study aims to examine 1st-line managers' (FLMs') experiences in managing the workplace social environment (WSE).

BACKGROUND

FLMs are responsible for the establishment and maintenance of supportive WSE essential for effective teamwork. Poorly managed WSE and dysfunctional teams hold negative implications for patients, teams, and organizations.

METHODS

This was a qualitative descriptive study, using content analysis of individual and focus group interviews with FLMs and directors.

RESULTS

FLMs play a critical role in the management of the WSE; however, the task is fraught with constraints and challenges including competing demands, lack of support, and insufficient training. Findings explicate how competing demands and communication challenges impede the successful management of the WSE.

CONCLUSIONS

Given the importance of a healthy WSE to patient, professional, and organizational outcomes, FLMs need support, training, and resources to assist them in managing the social environment alongside other competing priorities.

Attributes of context relevant to healthcare professionals' use of research evidence in clinical practice: a multi-study analysis

BACKGROUND

To increase the likelihood of successful implementation of evidence-based practices, researchers, knowledge users, and healthcare professionals must consider aspects of context that promote and hinder implementation in their setting. The purpose of the current study was to identify contextual attributes and their features relevant to implementation by healthcare professionals and compare and contrast these attributes and features across different clinical settings and healthcare professional roles.

METHODS

We conducted a secondary analysis of 145 semi-structured interviews comprising 11 studies (10 from Canada and one from Australia) investigating healthcare professionals' perceived barriers and enablers to their use of research evidence in clinical practice. The data was collected using semi-structured interview guides informed by the Theoretical Domains Framework across different healthcare professional roles, settings, and practices. We analyzed these data inductively, using constant comparative analysis, to identify attributes of context and their features reported in the interviews. We compared these data by (1) setting (primary care, hospital-medical/surgical, hospital-emergency room, hospital-critical care) and (2) professional role (physicians and residents, nurses and organ donor coordinators).

RESULTS

We identified 62 unique features of context, which we categorized under 14 broader attributes of context. The 14 attributes were resource access, work structure, patient characteristics, professional role, culture, facility characteristics, system features, healthcare professional characteristics, financial, collaboration, leadership, evaluation, regulatory or legislative standards, and societal influences. We found instances of the majority (n = 12, 86%) of attributes of context across multiple (n = 6 or more) clinical behaviors. We also found little variation in the 14 attributes of context by setting (primary care and hospitals) and professional role (physicians and residents, and nurses and organ donor coordinators).

CONCLUSIONS

There was considerable consistency in the 14 attributes identified irrespective of the clinical behavior, setting, or professional role, supporting broad utility of the attributes of context identified in this study. There was more variation in the finer-grained features of these attributes with the most substantial variation being by setting.

IMPROVING TRANSITIONS IN CARE FOR CHILDREN WITH COMPLEX CARE NEEDS IN NOVA SCOTIA

BACKGROUND

Children with complex care needs are a small yet resource intensive population in Canada. At present, there is wide variation in the way in which this population is characterized in the clinical and research literature. Transitions from hospital to home for these children can be complicated by variation in available services and resources in their home community; complex technological logistics; and a sharp disjuncture between discharge instructions provided to families and implementation in their home communities.

OBJECTIVES

Develop policy recommendations for inclusion in a Nova Scotia strategy to support transitions in care for these children with medical complexity.

DESIGN/METHODS

We used a mixed method design. During phase 1 we developed six cases representing children with different levels of complexity. Cases were informed by parent and provider interviews at 4 time points, chart audits and validated measures of caregiver distress. In phase 2, we conducted key stakeholder interviews across Nova Scotia to identify barriers and facilitators to successful transitions in care. A multi-sector consensus meeting was held during phase 3 to discuss study findings and refine key recommendations for inclusion in a Nova Scotia strategy.

RESULTS

Six cases included children aged 15 days to 9 years old who were followed by as many as seven services and lived 50–300 km from IWK Health Centre. Key stakeholder interviews were conducted with 4 nurses, 4 physicians, and 1 administrator from 5 communities across Nova Scotia. A range of inter-institutional communication challenges and limited educational resources were identified as a key barrier. Participants identified the need for a nurse-coordinator role to act as a resource for both families and health providers in the community. A half-day consensus meeting 20 stakeholders from different health and government sectors was held. Proposed policy recommendations included: (1) consistent, timely, and discharge planning, (2) a comprehensive repository of resources for health care providers and families, (3) educational outreach strategy to build capacity for providers and families, (4) a nurse-coordinator role in each health zone to act a liaison and resource for health care providers and families, (5) work with existing provincial programs and services to develop policies and tools that are unique to a paediatric population, (6) adopt an established definitional framework for Children with Medical Complexity.

CONCLUSION

Our collaborative patient-centred approach to understanding how children with complex care needs currently navigate transitions in care in Nova Scotia provided a foundation for developing recommendations for a provincial strategy.

Home-based vs inpatient education for children newly diagnosed with type 1 diabetes

BACKGROUND

Initial management of children diagnosed with type 1 diabetes (T1D) varies worldwide with sparse high quality evidence regarding the impact of different models of care.

AIM

To compare the inpatient model of care with a hybrid home-based alternative, examining metabolic and psychosocial outcomes, diabetes knowledge, length of stay, and patient satisfaction.

SUBJECTS AND METHODS

The study design was a randomized-controlled trial. Inclusion criteria were: newly diagnosed T1D, aged 3 to 16 years, living within approximately 1 hour of the hospital, English-speaking, access to transport, absence of significant medical or psychosocial comorbidity. Patients were randomized to standard care with a 5 to 6 day initial inpatient stay or discharge after 2 days for home-based management. All patients received practical skills training in the first 48 hours. The intervention group was visited twice/day by a nurse for 2 days to assist with injections, then a multi-disciplinary team made 3 home visits over 2 weeks to complete education. Patients were followed up for 12 months. Clinical outcomes included HbA1c, hypoglycemia, and diabetes-related readmissions. Surveys measured patient satisfaction, diabetes knowledge, family impact, and quality of life.

RESULTS

Fifty patients were recruited, 25 to each group. There were no differences in medical or psychosocial outcomes or diabetes knowledge. Average length of admission was 1.9 days shorter for the intervention group. Families indicated that with hindsight, most would choose home- over hospital-based management.

CONCLUSIONS

With adequate support, children newly diagnosed with T1D can be safely managed at home following practical skills training.

Understanding context in knowledge translation: a concept analysis study protocol

AIM

To conduct a concept analysis of clinical practice contexts (work environments) that facilitate or militate against the uptake of research evidence by healthcare professionals in clinical practice. This will involve developing a clear definition of context by describing its features, domains and defining characteristics.

BACKGROUND

The context where clinical care is delivered influences that care. While research shows that context is important to knowledge translation (implementation), we lack conceptual clarity on what is context, which contextual factors probably modify the effect of knowledge translation interventions (and hence should be considered when designing interventions) and which contextual factors themselves could be targeted as part of a knowledge translation intervention (context modification).

DESIGN

Concept analysis.

METHODS

The Walker and Avant concept analysis method, comprised of eight systematic steps, will be used: (1) concept selection; (2) determination of aims; (3) identification of uses of context; (4) determination of defining attributes of context; (5) identification/construction of a model case of context; (6) identification/construction of additional cases of context; (7) identification/construction of antecedents and consequences of context; and (8) definition of empirical referents of context. This study is funded by the Canadian Institutes of Health Research (January 2014).

DISCUSSION

This study will result in a much needed framework of context for knowledge translation, which identifies specific elements that, if assessed and used to tailor knowledge translation activities, will result in increased research use by nurses and other healthcare professionals in clinical practice, ultimately leading to better patient care.

Home oxygen for children with acute bronchiolitis

A prospective randomised controlled pilot study was performed comparing home oxygen therapy with traditional inpatient hospitalisation for children with acute bronchiolitis. Children aged 3-24 months with acute bronchiolitis, still requiring oxygen supplementation 24 h after admission to hospital, were randomly assigned to receive oxygen supplementation at home with support from "hospital in the home" (HiTH) or to continue oxygen supplementation in hospital. 44 children (26 male, mean age 9.2 months) were recruited (HiTH n = 22) between 1 August and 30 November 2007. Only one child from each group was readmitted to hospital and there were no serious complications. Children in the HiTH group spent almost 2 days less in a hospital bed than those managed as traditional inpatients: HiTH 55.2 h (interquartile range (IQR) 40.3-88.9) versus in hospital 96.9 h (IQR 71.2-147.2) p = 0.001. Home oxygen therapy appears to be a feasible alternative to traditional hospital oxygen therapy in selected children with acute bronchiolitis.

Co-Bedding Twins

BACKGROUND

Co-bedding, a developmental care practice for twins and multiples, has been theorized as a strategy to decrease the adverse neurodevelopmental effects that may be associated with hospitalization.

OBJECTIVE

The aim of this study was to determine the feasibility of study design, methods, and the measurement of desired outcomes for the development of a larger multicentered study.

RESULTS

Study findings were used to estimate effect size, determine staff and bedside care organization, evaluate feasibility of data collection measures, and identify issues related to recruitment and follow-up. Results were incorporated in the development of a larger multicentered trial grant proposal.

DISCUSSION

Pilot studies can play an important role in the development of a competitive grant proposal and efficient conduct of a research trial. Pilot studies strengthen a proposal by providing essential baseline information. A general overview of the purpose of pilot studies is provided here, along with a description of the process of using findings from a pilot study to inform the development of a larger multisite trial. Findings from this pilot study examining the effects of co-bedding on twins and their parents are used to revise the research protocol for a larger multisite trial. These changes, which lead to improvement to the protocol, and the rational for these changes are highlighted.

Thyrotoxic bone disease in women: a potentially reversible disorder

OBJECTIVE

To measure changes in spinal and femoral neck bone mineral densities in patients treated for Graves thyrotoxicosis.

DESIGN

Cohort study.

SETTING

Tertiary care center.

PATIENTS

Fifteen women with active Graves thyrotoxicosis. Six patients were premenopausal and nine were postmenopausal. All patients had evidence of thyrotoxicosis as indicated by a raised total serum thyroxine, suppressed serum thyroid-stimulating hormone, and an elevated technetium-99m pertechnetate thyroid scan. A control group of 15 healthy volunteers matched for age, sex, and menopausal status were followed during the same period.

MEASUREMENTS

Bone mineral density was measured by dual-energy x-ray absorptiometry at baseline and after 12 months of antithyroid therapy when euthyroidism had been achieved.

RESULTS

After 12 months of therapy, total serum thyroxine, total serum triiodothyronine, serum alkaline phosphatase, and serum bone Gla-protein activities had returned to normal in all patients (P < 0.001 for all comparison between initial and final biochemical measurements). During this interval, the mean lumbar spine bone mineral increased from an initial value of 1.01 g/cm2 to 1.07 g/cm2, an increase of 6.6% per year (95% CI, 3.6% to 9.6%) (P < 0.001 compared with controls). Increases in femoral neck (1.2%/y; CI, -2.1% to 4.5%; P = 0.2 compared with controls) and femoral trochanter bone mineral (3.2%/y; CI, 2.4% to 8.7%; P = 0.2 compared with controls) were not statistically significant. Using forced-entry multiple regression analysis, the severity of the thyrotoxicosis was independently associated with the percentage increment in lumbar spine bone mineral density after 12 months of antithyroid therapy.

CONCLUSION

Effective treatment of Graves thyrotoxicosis was associated with increases in lumbar spine and femoral neck bone mineral. Although the changes in bone mineral were modest, our data suggest that thyrotoxic bone loss may be a reversible disorder.

Three new contaminants detected in postmortem blood samples

Three contaminants were identified during drug screening of postmortem blood samples which had been stored in glass bottles with a black rubber seal. Two of these contaminants, cyanoethyl dimethyldithiocarbamate and N-phenyl-2-naphthylamine, were found to come from the rubber seal of some bottles. The third contaminant was not a single compound but rather a mixture of aryl phosphates with a composition very similar to technical grade tritolyl phosphate. The origin of these phosphates is at present unknown.

Incidence of drug and alcohol intake in road traffic accident victims

The analysis of 425 samples of blood, taken from people killed in motor vehicle accidents, showed that drugs were present in about 10% of samples, whereas alcohol was present in 51%. All drugs identified were available on prescription, and the most commonly found drug was diazepam.

A rapid extraction method for acidic drugs in hemolyzed blood

A simple and efficient method, based on the adsorption properties of octadecasilane bonded silica, is described for the rapid extraction of acidic drugs from whole post mortem blood. The blood was diluted, passed through an extraction column containing the bonded silica and the absorbed drugs were eluted with methanol. Following extraction into diethylether, the drugs were methylated and chromatographed. Recoveries were generally in excess of 80% at the microgram/mL level and the method substantially reduced the quantity of co-extracted lipids normally found in the acid extracts of hemolyzed blood. The procedure proved suitable for up to 2 mL blood and yielded clean extracts for gas chromatographic analysis.

Dormancy in somatic embryos and seeds ofVitis: changes in endogenous abscisic acid during embryogeny and germination

Abscisic acid (ABA) in extracts of somatic embryos and seeds of Gloryvine (Vitis vinifera L.xV. rupestris Scheele) was measured by gas chromatography-mass spectrometry-selected ion monitoring using deuterated ABA, (±)-[C-3Me-(2)H3]ABA, ([(2)H3]ABA) as internal standard. The ABA content increased rapidly during embryogeny (0.035 ng/embryo at the globular stage to 0.22 ng/embryo at the mature stage). The level of ABA in the tissues of somatic embryos, expressed in ng/mg dry weight, decreased from the globular stage (0.76 ng/mg) to the mature stage (0.25 ng/mg). Chilling (4° C) induced normal germination of seeds and mature somatic embryos and precocious germination of globular, heart-shaped and torpedoshaped somatic embryos. In all cases chilling led to a marked reduction in endogenous ABA. Exogenous (±)-ABA inhibited the germination of chilled somatic embryos.

Leaching of 2-(2-hydroxyethylmercapto) benzothiazole into contents of disposable syringes

A contaminant was found to leach into the contents of two brands of disposable syringes. It was identified as 2-(2-hydroxyethylmercapto) benzothiazole and is believed to be formed during manufacture of the syringes as a result of a reaction between 2-mercaptobenzothiazole, a rubber vulcanization accelerator, and ethylene oxide, used for sterilization. The contaminant was isolated form the rubber plunger-seal and identified using mass, NMR, and UV spectroscopic methods. The amount of contaminant appearing in the contents of syringes was measured; up to 140 micro g was found under clinically relevant conditions. This finding has important implications with respect to the use of these syringes for drug administration and for the collection of blood for drug analyses.

Quantitation of doxapram in blood, plasma and urine

Methods for the quantitation of doxapram in blood, plasma and urine have been developed. Following extraction, gas-liquid chromatography was used to separate doxapram from basic metabolites. Doxapram was detected by mass spectrometry for blood and plasma assays, and by flame ionisation for urine assays. The limit of reliable quantitation in blood and plasma was 10 ng and in urine 500 ng, the coefficients of variation being 6.37%, 1.72% and 2.31% respectively. To illustrate the clinical applicability of the assay methods, plasma, blood and urine levels were monitored in a premature newborn following an intravenous infusion of doxapram.

Cardenolide analogues: 10--characterization of cardiac glycosides by chemical ionization mass spectrometry

The potential of chemical ionization mass spectrometry for the characterization of naturally occurring and semi-synthetic cardiac glycosides has been investigated. Methane, isobutane and ammonia were used as reactant gases. With the exception of ouabain, the ammonia chemical ionization mass spectra of the cardiac glycosides examined in this work contained abundant [M + NH4]+ions and abundant fragment ions formed by cleavage of glycoside bonds. Ammonia chemical ionization mass spectrometry was found to provide a rapid and sensitive method for the characterization of the products of glycosidation reactions. In contrast, the methane and isobutane chemical ionization mass spectra of the cardiac glycosides, with the exception of ouabain, did not contain protonated molecular ions and did not contain abundant fragment ions above m/z 400.

The identification of eight hydroxylated metabolites of etidocaine by chemical ionization mass spectrometry

1. Eight hydroxylated metabolites of etidocaine have been identified in urine of man by g.l.c.-chemical ionization mass spectrometry, using methane and a mixture of methane and deuterium oxide as reactant gases. 2. The metabolites identified were N-(2,6-dimethyl-3- and 4-hydroxyphenyl-)-2-(N,N-ethylpropylamino)butyramides, N-(2,6-dimethyl-3- and 4-hydroxyphenyl)-2-aminobutyramides, N-(2,6-dimethyl-3- and 4-hydroxyphenyl)-2-(N-ethylamino)butyramides, and N-(2,6-dimethyl-3- and 4-hydroxyphenyl)-2-(N-propylamino)butyramides. 3. The eight metabolites represent about 10% of the oral dose of etidocaine.

Metabolism and urinary excretion of benzhexol in humans

1. Benzhexol and three of its metabolites excreted in urine in man have been investigated by g.l.c.--mass spectrometry. 2. Three isomeric hydroxylated metabolites were identified as the 1-(hydroxycyclohexyl)-1-phenyl-3-piperidinopropan-1-ols. 3. The amounts of benzhexol and its identified metabolites have been semiquantitatively determined after a single oral dose in two healthy adults. Approx. 56% of the dose was excreted as the hydroxylated metabolites. The levels of benzhexol excreted were too low to be measured by the techniques used.

Cyclic metabolites of etidocaine in humans

1. Three cyclic metabolites of etidocaine excreted in urine of man have been investigated by g.l.c.-mass spectrometry. 2. These metabolites have been identified as 3-(2,6-dimethylphenyl)-5-ethyl-2,4-imidazolidinedione, 1-(2,6-dimethylphenyl)-2-methyl-4-ethyl-2-imidazolin-5-one and 1-(2,6-dimethylphenyl)-2,4-diethyl-2-imidazoline-5-one. 3. Formation in vivo of two of the metabolites is proposed to proceed via carbinolamine intermediates.

Metabolism of etidocaine in man

1. Etidocaine and eight metabolites excreted in urine of man have been detected by g.l.c. and investigated by g.l.c.-mass spectrometry. 2. Five metabolites have been identified by comparison with authentic compounds as 2-amino-2'-butyroxylidide, 2-N-ethylamino-2'-butyroxylidide, 2-N-propylamino-2'-butyroxylidide, 2.6-dimethylaniline and 4-hydroxy-2,6-dimethylaniline. 3. The structure of one of the remaining three metabolites is proposed to be 2-methyl-N3-(2,6-dimethylphenyl)-5-ethyl-4-imidazolidinone. 4. The amounts of etidocaine and seven of its metabolites excreted in a 48 h urine following epidural administration to a patient have been estimated. Approx. 31% of the dose was accounted for.

Metabolism and urinary excretion of chlormethiazole in humans

1. Chlormethiazole and five of its metabolites excreted in urine in man have been investigated by g.l.c.-mass spectrometry. 2. Four metabolites have been identified by comparison with authentic compounds as 5-acetyl-4-methylthiazole, 5-(1-hydroxyethyl)-4-methylthiazole, 5-(2-hydroxyethyl)-4-methylthiazole and 4-methyl-5-thiazoleacetic acid; 4-methyl-5-thiazoleacetaldehyde is proposed for the other metabolite. 3. The amounts of chlormethiazole and its identified metabolites excreted in urine have been quantitatively determined after a single oral dose in three healthy adults. Approximately 16% of the dose was excreted as chlormethiazole, 5-acetyl-4-methylthiazole, 5-(1-hydroxyethyx)-4-methylthiazole and 4-methyl-5-thiazoleacetic acid.

Optical means for enhancing the sensitivity of a tri-alkali photocathode

With conventional transmissive photocathodes, an appreciable amount of the incident light passes through the photocathode layer without contributing to the electron emission. It is possible, at certain predetermined wavelengths, to reduce these light losses and thereby to increase the quantum efficiency of the cathode by making it part of a reflection interference filter. In practice, this involves the deposition of the photocathode on a dielectric which is, in turn, deposited on an opaque mirror. The thin-film optics of the above arrangement has been considered theoretically, and the possible increase in light absorption, and hence in electron emission, could be predicted. Evaluation of actual tri-alkali (S-20) photocathodes constructed along the above lines agree with, and at times even exceed, the theoretical enhancement factor of about three to five, thus establishing the practicability of the method considered.