The impact of leadership and quality climate on hospital performance

Objective. To explore the relationship between leadership effectiveness and health-care trust performance, taking into account external quality measures and the number of patient complaints; also, to examine the role of care quality climate as a mediator. Design. We developed scales for rating leadership effectiveness and care quality climate. We then drew upon UK national indices of health-care trust performance—Commission for Health Improvement star ratings, Clinical Governance Review ratings and the number of patient complaints per thousand. We conducted statistical analysis to examine any significant relationships between predictor and outcome variables. Setting. The study is based on 86 hospital trusts run by the National Health Service (NHS) in the UK. The data collection is part of an annual staff survey commissioned by the NHS to explore the quality of working life. Participants. A total of 17 949 employees were randomly surveyed (41% of the total sample). Results. Leadership effectiveness is associated with higher Clinical Governance Review ratings and Commission for Health Improvement star ratings for our sample (ß = 0.42, P < 0.05; ß = 0.37, P < 0.05, respectively), and lower patient complaints (ß = –0.57, P < 0.05). In addition, 98% of the relationship between leadership and patient complaints is explained by care quality climate. Conclusions. Results offer insight into how non-clinical leadership may foster performance outcomes for health-care organizations. A frequently neglected area—patient complaints—may be a valid measure to consider when assessing leadership and quality in a health-care context.

The experiences and perceptions of fathers attending the birth and immediate care of their baby

Fathers in the United Kingdom (UK) usually attend the birth and immediate care of their baby. They also have an increasing presence during complicated and preterm childbirth, newborn resuscitation and early neonatal unit(NNU) care. However, there is limited evidence about the effect of these experiences on them. The aim of this study was to gain an understanding of the experiences of fathers encountering these situations. The study consisted of three phases and was undertaken in one National Health Service trust in the UK. Qualitative semi-structured interviews using a phenomenological approach were undertaken with 20 first-time fathers present at the delivery, resuscitation and/or admission of their baby to the NNU. Direct observations were made of 22 normal and complicated deliveries and initial newborn care and qualitative semi-structured interviews using the critical incident approach were undertaken with 37 health care professionals (HCPs). The study generated qualitative and quantitative data that were analysed accordingly. The findings show that most fathers were involved for at least some of the time and often spontaneously initiated their involvement. Their most important need was for information. They were usually more concerned about their partner, irrespective of the baby?s need for resuscitation and NNU care. To facilitate their involvement, fathers needed guidance and support from HCPs, particularly delivery suite midwives. Most HCPs recognised the needs of fathers and ways in which they could be helped to connect with their experience. However, these needs were not always met, usually because of inadequate staffing levels, a lack of resources or a mother-centred philosophy of care. The findings suggest the service often determines the extent to which fathers are involved. It is anticipated that these findings will inform HCP education and training and the development of both policy and health education thereby enhancing the quality of care provision for fathers.

Ocular compatibility of hydrogel contact lenses:deposition and clinical performance

Currently over 50 million people worldwide wear contact lenses, of which over 75% wear hydrogel lenses. Significant deposition occurs in approximately 80% of hydrogel lenses and many contact lens wearers cease wearing lenses due to problems associated with deposition. The contact lens field is not alone in encountering complications associated with interactions between the body and artificial devices. The widespread use of man-made materials to replace structures in the body has emphasised the importance of studies that examine the interactions between implantation materials and body tissues.This project used carefully controlled, randomized clinical studies to study the interactive effects of contact lens materials, care systems, replacement periods and patient differences. Of principal interest was the influence of these factors on material deposition and their subsequent impact on subjective performance. A range of novel and established analytical techniques were used to examine hydrogel lenses following carefully controlled clinical studies in which clinical performance was meticulously monitored. These studies established the inter-relationship between clinical performance and deposition to be evaluated. This project showed that significant differences exist between individuals in their ability to deposit hydrogel lenses, with approximately 20% of subjects displaying significant deposition irrespective of the lens material. Additionally, materials traditionally categorised together show markedly different spoilation characteristics, which are wholly attributable to their detailed chemical structure. For the first time the in vivo deposition kinetics of both protein and lipid in charged and uncharged polymers was demonstrated. In addition the importance of care systems in the deposition process was shown, clearly demonstrating the significance of the quality rather than the quantity of deposition in influencing subjective performance.

Development and psychometric tests of the Chinese-version low vision quality of life questionnaire

Background/Aims: To develop and assess the psychometric validity of a Chinese language Vision Health related quality-of-life (VRQoL) measurement instrument for the Chinese visually impaired. Methods: The Low Vision Quality of Life Questionnaire (LVQOL) was translated and adapted into the Chinese-version Low Vision Quality of Life Questionnaire (CLVQOL). The CLVQOL was completed by 100 randomly selected people with low vision (primary group) and 100 people with normal vision (control group). Ninety-four participants from the primary group completed the CLVQOL a second time 2 weeks later (test-retest group). The internal consistency reliability, test-retest reliability, item-internal consistency, item-discrimination validity, construct validity and discriminatory power of the CLVQOL were calculated. Results: The review committee agreed that the CLVQOL replicated the meaning of the LVQOL and was sensitive to cultural differences. The Cronbach's α coefficient and the split-half coefficient for the four scales and total CLVQOL scales were 0.75-0.97. The test-retest reliability as estimated by the intraclass correlations coefficient was 0.69-0.95. Item-internal consistency was >0.4 and item-discrimination validity was generally <0.40. The Varimax rotation factor analysis of the CLVQOL identified four principal factors. the quality-of-life rating of four subscales and the total score of the CLVQOL of the primary group were lower than those of the Control group, both in hospital-based subjects and community-based subjects. Conclusion: The CLVQOL Chinese is a culturally specific vision-related quality-of-life measure instrument. It satisfies conventional psychometric criteria, discriminates visually healthy populations from low vision patients and may be valuable in screening the local community as well as for use in clinical practice or research. © Springer 2005.

Cost of illness in benign prostatic hyperplasia: A review

The paper provides a systematic review on the cost-of-illness studies in an age-associated condition with high prevalence, benign prostatic hyperplasia (BPH), published in Medline between 2005 and 2015. Overall 11 studies were included, which were conducted in 8 countries. In the US, the annual direct medical costs per patient ranged from $255 to $5,729, while in Europe from €253 to €1,251. In 2008, in the UK total annual direct medical costs of BPH were £180.8 million at national level. In the US, overall costs of BPH management in the private sector were estimated at $3.9 billion annually, of which $500 million was attributable to productivity loss (year 1999). Due to demographic factors and possible surgical innovations in the field of urology, the costs of BPH are likely to increase in the future. Over the next decade the age of retirement is projected to rise, consequently, the indirect costs related to aging-associated conditions such as BPH are expected to soar. To promote the transparent and cost-effective management of BPH, development of rational clinical guidelines would be essential that may lead to significant improvement in quality of care as well as reduction in healthcare expenditure.

Stressors, mediators, and health care outcomes of home enteral nutrition in family caregivers and their older adult care recipients

Family caregivers manage home enteral nutrition (HEN) for over 77% of an estimated 1 of every 400 Medicare recipients. Increasing usage of HEN in older adults combined with reliance on family caregivers raises concerns for the quality, outcomes, and costs of care. These concerns are relevant in light of Medicare limitations on nursing assistance and non-reimbursement for nutrition services, despite annual costs of over $600 million. This study applied stress process theories to assess stressor, mediator, and outcome variables salient to HEN and caregiving. In-home structured interviews occurred with a multi-ethnic sample of 30 caregiving dyads at 1–3 months after discharge on HEN. Care recipients were aged ≥60 (M = 68.4 years) and did not have dementia. Caregivers were aged ≥21, unpaid, and lived within 45 minutes of care recipients. Caregivers performed an average of 19.7 tasks daily for 61.9 hours weekly. Training needs were identified for 33 functional, care management, technical, and nutritional tasks. Preparedness scores were low (M = 1.73/4.0), and positively correlated with competence, self-rated quality of care and positive feelings, and negatively with overload, role captivity, and negative feelings (Ps < .05). Caregivers had multiple changes in lifestyle and dietary behaviors. Lifestyle changes positively correlated with overload, and negatively with preparedness and positive feelings. Dietary changes positively correlated with number of tasks, overload, role captivity and negative feelings, and negatively with preparedness (Ps < .01). Fifty-seven percent of caregivers aged >50 were at nutrition risk. Care recipients fared worse. Average weight change was −4.35 pounds (P < .001). Physical complications interrupted daily enteral infusions. Water intake was half of fluid need and associated with signs of dehydration (P < .001). Physical and social function was poor, with older subjects more impaired ( P < .04). Those with better prepared or less overloaded caregivers had higher functionality and QOL (P < .002). Complications, type of feeding tube, and caregiver preparedness correlated with frequency of health care utilization (Ps < .05). Efficacy of HEN in older adults requires specialized caregiver training, attention to caregivers' needs, and frequent monitoring from a highly skilled multidisciplinary team including dietitians. ^

The impact of selected factors in nurses' attitudes toward bedside computers

The purpose of this study was to determine the impact of selected factors on nurses' attitudes toward bedside computers. Bedside computer systems, also referred to as point-of-care systems, are clinical information systems that allow documentation of patient care and retrieval of data at the patient's bedside, or in close proximity to where care is delivered. The adoption of bedside computer systems appears to be increasing among U.S. institutions. As healthcare institutions undertake automation projects, they face many challenges associated with implementing large-scale change. ^ The study explored four factors and their relationship to nurses' attitudes toward bedside computers. A pre-bedside implementation survey of 184 staff nurses did not demonstrate a relationship between previous computer experience and nurses' attitudes toward bedside computers (p > .05). The data did not indicate a relationship between nurses' formal education and their attitude toward bedside computers (p > .05). The data did support a relationship between nurses' previous computer experience and their comfort in the use of bedside computers (p < .0005). Using a quasi-experimental control group design, attitudes of nurses were studied over an 18 month period. The Pre versus Post Survey data indicated that nurses who used bedside computers, the experimental group, had more positive attitudes than the nurses who did not use bedside computers, the control group (p < .0005). ^ The findings are significant to institutions implementing bedside computers, to the human resource development staff overseeing bedside computer training, and to the practice of clinical nursing. ^

Personality and job performance: The mediating roles of leader -member exchange quality and action control

The present investigation examined the relationships among personality (as conceptualized by the Big Five Factors), leader-member exchange (LMX) quality, action control, organizational citizenship behaviors (OCB), and overall job performance (OJP). Two mediator variables were proposed and tested in this study: LMX and Action Control. Two-hundred and seven currently employed regular elementary school classroom teachers provided data during the 2000–2001 academic school year. Teachers provided personality, LMX quality (member or subordinate perspective), action control, job tenure, and demographic data. Nine school administrators (i.e., Principals, Assistant Principals) were the source for supervisor ratings of OCB, OJP, and LMX quality (leader or supervisor perspective). In eight of the nine total schools, teachers completed questionnaires during an after-school teacher gathering; in the remaining school location questionnaires were dropped off, distributed to teachers, and re-collected two weeks later. Results indicated a significant relationship between the OCB scale and overall supervisory ratings of OJP. The relationship among the big five factors of personality and OJP did not reach statistical significance, nor did the relationships among personality and OCB. The data indicated that none of the teacher tenure variables (i.e., teacher, school, or time worked with principal tenure) moderated the personality-OCB relationship nor the personality-OJP relationship. Finally, a review of the correlations among the variables of interest precluded conducting a mediation between personality-performance by OCB, mediation of personality-OCB by action control, and mediation of personality-OCB by LMX. In conclusion, the data reveal that personality was not significantly correlated with supervisory ratings of OJP or significantly related to supervisory ratings of overall OCB. Moreover, LMX quality and action control did not mediate the relationships between Personality-OJP nor the Personality-OCB relationship. Significant relationships were found between disengagement and overall LMX quality and between Initiative and overall LMX quality (both LMX-Teacher perspectives) as well as between personality variables and both Disengagement and Initiative action control variables. Despite the limitations inherent in this study, these latter findings suggest “lessons” for teachers and school administrators alike. ^

The effects of advanced practice nurses (APNs) as intensivists in a surgical intensive care unit (SICU) on patient outcomes, healthcare charges, and apn intensivist services in the SICU

Intensive Care Units (ICUs) account for over 10 percent of all US hospital beds, have over 4.4 million patient admissions yearly, approximately 360,000 deaths, and account for close to 30% of acute care hospital costs. The need for critical care services has increased due to an aging population and medical advances that extend life. The result is efforts to improve patient outcomes, optimize financial performance, and implement models of ICU care that enhance quality of care and reduce health care costs. This retrospective chart review study examined the dose effect of APN Intensivists in a surgical intensive care unit (SICU) on differences in patient outcomes, healthcare charges, SICU length of stay, charges for APN intensivist services, and frequency of APNs special initiatives when the SICU was staffed by differing levels of APN Intensivist staffing over four time periods (T1-T4) between 2009 and 2011. The sample consisted of 816 randomly selected (204 per T1-T4) patient chart data. Study findings indicated reported ventilator associated pneumonia (VAP) rates, ventilator days, catheter days and catheter associated urinary tract infection (CAUTI) rates increased at T4 (when there was the lowest number of APN Intensivists), and there was increased pressure ulcer incidence in first two quarters of T4. There was no statistically significant difference in post-surgical glycemic control (M = 142.84, SD = 40.00), t (223) = 1.40, p = .17, and no statistically significant difference in the SICU length of stay among the time-periods (M = 3.27, SD = 3.32), t (202) = 1.02, p = .31. Charges for APN services increased over the 4 time periods from $11,268 at T1 to $51,727 at T4 when a system to capture APN billing was put into place. The number of new APN initiatives declined in T4 as the number of APN Intensivists declined. Study results suggest a dose effect of APN Intensivists on important patient health outcomes and on the number of APNs initiatives to prevent health complications in the SICU. ^

The Effect of Carbohydrate Amount, Quality and Type on Arterial Pulse Pressure in Cuban-Americans with and Without Type 2 Diabetes

Background: Arterial pulse pressure, the difference between systolic and diastolic blood pressure, has been used as an indicator (surrogate measure) of arterial stiffness. High arterial pulse pressure (> 40) has been associated with increased cardiovascular disease and mortality. Several clinical trials have reported that the proportion of calories from carbohydrate has an effect on blood pressure. The primary objective of this study was to assess arterial pulse pressure and its association with carbohydrate quantity and quality (glycemic load) with diabetes status for a Cuban American population. Methods: A single point analysis included 367 participants. There was complete data for 365 (190 with and 175 without type 2 diabetes). The study was conducted in the investigator’s laboratory located in Miami, Florida. Demographic, dietary, anthropometric and laboratory data were collected. Arterial pulse pressure was calculated by the formula systolic minus the diastolic blood pressure. Glycemic load, fructose, sucrose, percent of average daily calories from carbohydrate, fat and protein, grams of fiber and micronutrient intakes were calculated from a validated food frequency questionnaire. Results: The mean arterial pulse pressure was significantly higher in participants with (52.9 ± 12.4) than without (48.6 ± 13.4) type 2 diabetes. The odds of persons with diabetes having high arterial pulse pressure (>40) was 1.85 (95% CI =1.09, 3.13); p=0.023. For persons with type 2 diabetes higher glycemic load was associated with lower arterial pulse pressure. Conclusions: Arterial pulse pressure and diet are modifiable risk factors of cardiovascular disease. Arterial pulse pressure may be associated with carbohydrate intake differently considering diabetes status. Results may be due to individuals with diabetes following dietary recommendations. The findings of this study suggest clinicians take into consideration how medical condition, ethnicity and diet are associated with arterial pulse pressure before developing a medical nutrition therapy plan in collaboration with the client.

Perceptions of health care: perspectives from adolescents with physical disabilities and their parents

Patient satisfaction with health care is an important indicator of quality services and has been related to positive health outcomes. Because little is known about whether adolescents with physical disabilities are satisfied with the services they receive, the current study investigated the extent to which adolescents are satisfied with health care services, aspects of care adolescents identify as important to their satisfaction, similarities between adolescent and parent perceptions of care, and the relationship between adolescent perceptions of care and their intentions to adhere to treatment recommendations. Following recruitment from a pediatric health center, adolescents and their parents (n = 42) completed questionnaires to assess their perceptions regarding various aspects of health care services. Participants were very satisfied with services received; interpersonal aspects of care were very important to them. Adolescents’ satisfaction was not predictive of their intentions to adhere to treatment recommendations and their perspectives differed from those of their parents.

Development of an education resource for families and clients navigating through end-of-life care with at-home palliation

Background: Community health nurses (CHNs) play a pivotal role in providing end-of-life care to clients diagnosed with a life-threatening illness. Providing quality end-of-life care is an ethical obligation. Eastern Health’s palliative end-of-life care program (PEOLC) offers nursing care, equipment, services, and support. However, the caregiver’s need for practical information about end-of-life issues is not addressed. Purpose: To develop an educational resource to assist clients and families during end-of-life and to provide a framework for new CHNs in home palliation. Methods: An informal Needs Assessment, a literature review, an environmental scan, and consultations with four CHNs involved with home palliation. Results: An educational resource was developed to address the practical end-of-life issues identified in the literature review and consultations. Conclusion: An improved delivery of care for at-home palliation in the community for clients and families, and a framework for new CHNs.

Advanced Techniques for Image Quality Assessment of Modern X-ray Computed Tomography Systems

X-ray computed tomography (CT) imaging constitutes one of the most widely used diagnostic tools in radiology today with nearly 85 million CT examinations performed in the U.S in 2011. CT imparts a relatively high amount of radiation dose to the patient compared to other x-ray imaging modalities and as a result of this fact, coupled with its popularity, CT is currently the single largest source of medical radiation exposure to the U.S. population. For this reason, there is a critical need to optimize CT examinations such that the dose is minimized while the quality of the CT images is not degraded. This optimization can be difficult to achieve due to the relationship between dose and image quality. All things being held equal, reducing the dose degrades image quality and can impact the diagnostic value of the CT examination.

A recent push from the medical and scientific community towards using lower doses has spawned new dose reduction technologies such as automatic exposure control (i.e., tube current modulation) and iterative reconstruction algorithms. In theory, these technologies could allow for scanning at reduced doses while maintaining the image quality of the exam at an acceptable level. Therefore, there is a scientific need to establish the dose reduction potential of these new technologies in an objective and rigorous manner. Establishing these dose reduction potentials requires precise and clinically relevant metrics of CT image quality, as well as practical and efficient methodologies to measure such metrics on real CT systems. The currently established methodologies for assessing CT image quality are not appropriate to assess modern CT scanners that have implemented those aforementioned dose reduction technologies.

Thus the purpose of this doctoral project was to develop, assess, and implement new phantoms, image quality metrics, analysis techniques, and modeling tools that are appropriate for image quality assessment of modern clinical CT systems. The project developed image quality assessment methods in the context of three distinct paradigms, (a) uniform phantoms, (b) textured phantoms, and (c) clinical images.

The work in this dissertation used the “task-based” definition of image quality. That is, image quality was broadly defined as the effectiveness by which an image can be used for its intended task. Under this definition, any assessment of image quality requires three components: (1) A well defined imaging task (e.g., detection of subtle lesions), (2) an “observer” to perform the task (e.g., a radiologists or a detection algorithm), and (3) a way to measure the observer’s performance in completing the task at hand (e.g., detection sensitivity/specificity).

First, this task-based image quality paradigm was implemented using a novel multi-sized phantom platform (with uniform background) developed specifically to assess modern CT systems (Mercury Phantom, v3.0, Duke University). A comprehensive evaluation was performed on a state-of-the-art CT system (SOMATOM Definition Force, Siemens Healthcare) in terms of noise, resolution, and detectability as a function of patient size, dose, tube energy (i.e., kVp), automatic exposure control, and reconstruction algorithm (i.e., Filtered Back-Projection– FPB vs Advanced Modeled Iterative Reconstruction– ADMIRE). A mathematical observer model (i.e., computer detection algorithm) was implemented and used as the basis of image quality comparisons. It was found that image quality increased with increasing dose and decreasing phantom size. The CT system exhibited nonlinear noise and resolution properties, especially at very low-doses, large phantom sizes, and for low-contrast objects. Objective image quality metrics generally increased with increasing dose and ADMIRE strength, and with decreasing phantom size. The ADMIRE algorithm could offer comparable image quality at reduced doses or improved image quality at the same dose (increase in detectability index by up to 163% depending on iterative strength). The use of automatic exposure control resulted in more consistent image quality with changing phantom size.

Based on those results, the dose reduction potential of ADMIRE was further assessed specifically for the task of detecting small (<=6 mm) low-contrast (<=20 HU) lesions. A new low-contrast detectability phantom (with uniform background) was designed and fabricated using a multi-material 3D printer. The phantom was imaged at multiple dose levels and images were reconstructed with FBP and ADMIRE. Human perception experiments were performed to measure the detection accuracy from FBP and ADMIRE images. It was found that ADMIRE had equivalent performance to FBP at 56% less dose.

Using the same image data as the previous study, a number of different mathematical observer models were implemented to assess which models would result in image quality metrics that best correlated with human detection performance. The models included naïve simple metrics of image quality such as contrast-to-noise ratio (CNR) and more sophisticated observer models such as the non-prewhitening matched filter observer model family and the channelized Hotelling observer model family. It was found that non-prewhitening matched filter observers and the channelized Hotelling observers both correlated strongly with human performance. Conversely, CNR was found to not correlate strongly with human performance, especially when comparing different reconstruction algorithms.

The uniform background phantoms used in the previous studies provided a good first-order approximation of image quality. However, due to their simplicity and due to the complexity of iterative reconstruction algorithms, it is possible that such phantoms are not fully adequate to assess the clinical impact of iterative algorithms because patient images obviously do not have smooth uniform backgrounds. To test this hypothesis, two textured phantoms (classified as gross texture and fine texture) and a uniform phantom of similar size were built and imaged on a SOMATOM Flash scanner (Siemens Healthcare). Images were reconstructed using FBP and a Sinogram Affirmed Iterative Reconstruction (SAFIRE). Using an image subtraction technique, quantum noise was measured in all images of each phantom. It was found that in FBP, the noise was independent of the background (textured vs uniform). However, for SAFIRE, noise increased by up to 44% in the textured phantoms compared to the uniform phantom. As a result, the noise reduction from SAFIRE was found to be up to 66% in the uniform phantom but as low as 29% in the textured phantoms. Based on this result, it clear that further investigation was needed into to understand the impact that background texture has on image quality when iterative reconstruction algorithms are used.

To further investigate this phenomenon with more realistic textures, two anthropomorphic textured phantoms were designed to mimic lung vasculature and fatty soft tissue texture. The phantoms (along with a corresponding uniform phantom) were fabricated with a multi-material 3D printer and imaged on the SOMATOM Flash scanner. Scans were repeated a total of 50 times in order to get ensemble statistics of the noise. A novel method of estimating the noise power spectrum (NPS) from irregularly shaped ROIs was developed. It was found that SAFIRE images had highly locally non-stationary noise patterns with pixels near edges having higher noise than pixels in more uniform regions. Compared to FBP, SAFIRE images had 60% less noise on average in uniform regions for edge pixels, noise was between 20% higher and 40% lower. The noise texture (i.e., NPS) was also highly dependent on the background texture for SAFIRE. Therefore, it was concluded that quantum noise properties in the uniform phantoms are not representative of those in patients for iterative reconstruction algorithms and texture should be considered when assessing image quality of iterative algorithms.

The move beyond just assessing noise properties in textured phantoms towards assessing detectability, a series of new phantoms were designed specifically to measure low-contrast detectability in the presence of background texture. The textures used were optimized to match the texture in the liver regions actual patient CT images using a genetic algorithm. The so called “Clustured Lumpy Background” texture synthesis framework was used to generate the modeled texture. Three textured phantoms and a corresponding uniform phantom were fabricated with a multi-material 3D printer and imaged on the SOMATOM Flash scanner. Images were reconstructed with FBP and SAFIRE and analyzed using a multi-slice channelized Hotelling observer to measure detectability and the dose reduction potential of SAFIRE based on the uniform and textured phantoms. It was found that at the same dose, the improvement in detectability from SAFIRE (compared to FBP) was higher when measured in a uniform phantom compared to textured phantoms.

The final trajectory of this project aimed at developing methods to mathematically model lesions, as a means to help assess image quality directly from patient images. The mathematical modeling framework is first presented. The models describe a lesion’s morphology in terms of size, shape, contrast, and edge profile as an analytical equation. The models can be voxelized and inserted into patient images to create so-called “hybrid” images. These hybrid images can then be used to assess detectability or estimability with the advantage that the ground truth of the lesion morphology and location is known exactly. Based on this framework, a series of liver lesions, lung nodules, and kidney stones were modeled based on images of real lesions. The lesion models were virtually inserted into patient images to create a database of hybrid images to go along with the original database of real lesion images. ROI images from each database were assessed by radiologists in a blinded fashion to determine the realism of the hybrid images. It was found that the radiologists could not readily distinguish between real and virtual lesion images (area under the ROC curve was 0.55). This study provided evidence that the proposed mathematical lesion modeling framework could produce reasonably realistic lesion images.

Based on that result, two studies were conducted which demonstrated the utility of the lesion models. The first study used the modeling framework as a measurement tool to determine how dose and reconstruction algorithm affected the quantitative analysis of liver lesions, lung nodules, and renal stones in terms of their size, shape, attenuation, edge profile, and texture features. The same database of real lesion images used in the previous study was used for this study. That database contained images of the same patient at 2 dose levels (50% and 100%) along with 3 reconstruction algorithms from a GE 750HD CT system (GE Healthcare). The algorithms in question were FBP, Adaptive Statistical Iterative Reconstruction (ASiR), and Model-Based Iterative Reconstruction (MBIR). A total of 23 quantitative features were extracted from the lesions under each condition. It was found that both dose and reconstruction algorithm had a statistically significant effect on the feature measurements. In particular, radiation dose affected five, three, and four of the 23 features (related to lesion size, conspicuity, and pixel-value distribution) for liver lesions, lung nodules, and renal stones, respectively. MBIR significantly affected 9, 11, and 15 of the 23 features (including size, attenuation, and texture features) for liver lesions, lung nodules, and renal stones, respectively. Lesion texture was not significantly affected by radiation dose.

The second study demonstrating the utility of the lesion modeling framework focused on assessing detectability of very low-contrast liver lesions in abdominal imaging. Specifically, detectability was assessed as a function of dose and reconstruction algorithm. As part of a parallel clinical trial, images from 21 patients were collected at 6 dose levels per patient on a SOMATOM Flash scanner. Subtle liver lesion models (contrast = -15 HU) were inserted into the raw projection data from the patient scans. The projections were then reconstructed with FBP and SAFIRE (strength 5). Also, lesion-less images were reconstructed. Noise, contrast, CNR, and detectability index of an observer model (non-prewhitening matched filter) were assessed. It was found that SAFIRE reduced noise by 52%, reduced contrast by 12%, increased CNR by 87%. and increased detectability index by 65% compared to FBP. Further, a 2AFC human perception experiment was performed to assess the dose reduction potential of SAFIRE, which was found to be 22% compared to the standard of care dose.

In conclusion, this dissertation provides to the scientific community a series of new methodologies, phantoms, analysis techniques, and modeling tools that can be used to rigorously assess image quality from modern CT systems. Specifically, methods to properly evaluate iterative reconstruction have been developed and are expected to aid in the safe clinical implementation of dose reduction technologies.

Resigning: a classic grounded theory of working within constraints when caring for stroke patients in the acute general care setting

This research aims to explore the challenges nurses face, when caring for stroke patients on a general medical/surgical ward, in the acute care setting and identify how nurses resolve or process this challenge. Healthcare environments continue to face the pressures of constraints such as reduced staffing levels, budgets, resources and less time, which influence care provision. Patient safety is central in care provision where nurses face the challenge of delivering best quality care when working within constraints. The incidence of stroke is increasing worldwide and internationally stroke units are the recognised minimum standard of care. In Ireland with few designated stroke units in operation many stroke patients are cared for in the acute general care setting. A classic grounded theory methodology was utilised for this study. Data was collected and analysed simultaneously through coding, constant comparison, theoretical sampling and memoing. Individual unstructured interviews with thirty two nurses were carried out. Twenty hours of non-participant observations in the acute general care setting were undertaken. The main concern that emerged was working within constraints. This concern is processed by nurses through resigning which consists of three phases; idealistic striving, resourcing and care accommodation. Through the process of resigning nurses engage in an energy maintenance process enabling them to continue working within constraints. The generation of the theory of resigning explains how nurses’ resolve or process working within constraints. This theory adds to the body of knowledge on stroke care provision. This theory has the potential to enhance nursing care, minimise burnout and make better use of resources while advocating for best care of stroke patients.

The Effects of Advanced Practice Nurses (APNs) as Intensivists in a Surgical Intensive Care Unit (SICU) on Patient Outcomes, Healthcare Charges, and APN Intensivist Services in the SICU

Intensive Care Units (ICUs) account for over 10 percent of all US hospital beds, have over 4.4 million patient admissions yearly, approximately 360,000 deaths, and account for close to 30% of acute care hospital costs. The need for critical care services has increased due to an aging population and medical advances that extend life. The result is efforts to improve patient outcomes, optimize financial performance, and implement models of ICU care that enhance quality of care and reduce health care costs. This retrospective chart review study examined the dose effect of APN Intensivists in a surgical intensive care unit (SICU) on differences in patient outcomes, healthcare charges, SICU length of stay, charges for APN intensivist services, and frequency of APNs special initiatives when the SICU was staffed by differing levels of APN Intensivist staffing over four time periods (T1-T4) between 2009 and 2011. The sample consisted of 816 randomly selected (204 per T1-T4) patient chart data. Study findings indicated reported ventilator associated pneumonia (VAP) rates, ventilator days, catheter days and catheter associated urinary tract infection (CAUTI) rates increased at T4 (when there was the lowest number of APN Intensivists), and there was increased pressure ulcer incidence in first two quarters of T4. There was no statistically significant difference in post-surgical glycemic control (M = 142.84, SD= 40.00), t (223) = 1.40, p = .17, and no statistically significant difference in the SICU length of stay among the time-periods (M= 3.27, SD = 3.32), t (202) = 1.02, p= .31. Charges for APN services increased over the 4 time periods from $11,268 at T1 to $51,727 at T4 when a system to capture APN billing was put into place. The number of new APN initiatives declined in T4 as the number of APN Intensivists declined. Study results suggest a dose effect of APN Intensivists on important patient health outcomes and on the number of APNs initiatives to prevent health complications in the SICU.