A Substruction Approach to Assessing the Theoretical Validity of Measures

Background Validity is about the logic, meaningfulness, and evidence used to defend inferences made when interpreting results. Substruction is a heuristic or process that visually represent the hierarchical structure between theory and measures. Purpose To describe substruction as a method for assessing the toretical validity of research measures. Methods Using Fawcett\u27s Conceptual-Theoretical-Empirical Structure. an exemplar is presented of substruction from the Individual and Family Self-Management Theory to the Striving to be strong study concepts and empirical measures. Results Substruction tables display evidence supporting theoretical validity of the instruments used in the study. Conclusion A high degree of congruence between theory and measure is critical to support the validity of the theory and to support attributions made about moderating, mediating, causal relationships, and intervention effects

Exercise training in patients awaiting liver transplantation and complex endovascular aortic aneurysm surgery

Introduction: Mounting evidence supports a relationship between physical fitness and perioperative outcomes. This thesis assesses the feasibility of a structured, preoperative exercise training programme in two high-risk surgical cohorts as two distinct studies: patients awaiting liver transplantation (LT) and fenestrated endovascular aortic aneurysm repair (FEVAR). Methods: Participants in the intervention arms for both studies performed thrice weekly directly supervised training sessions on a cycle ergometer for six weeks, individualised according to baseline fitness measured by cardiopulmonary exercise testing (CPET). Feasibility and acceptability outcomes were eligibility, recruitment, adverse events and adherence to exercise. The impact of training was assessed by repeat CPET after the intervention. In each study, changes in anaerobic threshold (AT) and peak oxygen-consumption (VO2peak) were compared to those among a group of control participants. The effect of exercise on cardiorespiratory fitness, health-related quality of life (HRQL) and exercise enjoyment was assessed along with the impact on postoperative outcomes. Results: Predefined feasibility and safety outcomes were met by both studies. A high participant drop-out rate in the LT study was noted (13 of 33 patients across both cohorts) attributed to transplantation, clinical deterioration and delisting. All 23 patients awaiting FEVAR (11 in the exercise and 12 in the control arm) completed the six week study period with a 97% compliance for exercise sessions in the intervention group. No difference in AT was observed between intervention and control cohorts in either study. In patients awaiting LT, an increase in VO2peak was demonstrated in the intervention group and a corresponding decrease in VO2peak in controls from baseline to week six. No change in HRQL scores were observed in either cohort, likewise no difference in postoperative intensive care lengths of stay were seen. Discussion: These two studies demonstrate feasibility for the exercise intervention and will form the basis for further evaluation of similar interventions in future studies

Short term physiological changes secondary to exercise in intermittent claudication : short term physiological changes in claudication

Background: In patients with intermittent claudication (IC), supervised exercise programmes (SEP) improve walking distance and quality of life (QoL); however the mechanisms by which these benefits are achieved remain unclear.Endothelial dysfunction is recognised as a trigger of the atheroinflammatory cascade and subsequent cardiovascular disease. In health, training improves cardiorespiratory physiology, inflammation and endothelial function. Changes in cardiorespiratory physiology, inflammatory markers and endothelial function are contradictory in IC.Objectives: This thesis aimed to assess the impact of SEP on cardiopulmonary physiology, endothelial function and athero-inflammatory markers in patients with IC.Methods: Following local research ethics committee and R & D approval, patients with IC were recruited from outpatient clinic. After providing informed written consent, patients underwent baseline assessment on two separate days.Session 1: participants completed a constant load treadmill test with pre and post exercise ankle brachial pressure indices.Session 2: measured QoL, endothelial function (EndoPAT2000, Itamar, Israel), venepuncture and a cardiopulmonary exercise test (CPET) using cycle ergometry. Participants then underwent a 12 week period of SEP which consisted of circuit training, with re-assessments at six and twelve weeks. The primary outcome measure was a 1.5ml/kg/min improvement in peak VO₂ after six weeks of exercise. Secondary outcomes included changes in endothelial function, quality of life, walking distance and inflammatory markers at both six and twelve weeks.Results: No significant improvements in CPET measurements, endothelial function or inflammation were demonstrated at any time point. Traditional markers of walking ability and QoL demonstrated an improvement by 12 weeks.Conclusions: The underlying mechanism through which exercise improves walking distance remains un-identified. Further work regarding the changes at the cellular level within the muscle is of importance

Preoperative supervised exercise and outcomes following elective abdominal aortic aneurysm repair

ObjectiveThe aim of this research was to evaluate the role of preoperative supervised exercise training on perioperative outcomes and cardiopulmonary exercise testing (CPET) parameters in patients undergoing elective abdominal aortic aneurysm (AAA) repair, and to analyse the value of different preoperative risk assessment tools in predicting postoperative complications following this intervention.MethodsParticipants in this project were patients with large AAA (≥ 5.5 cm), awaiting elective open or endovascular repair.Study 1: was a prospective randomised controlled trial. Participants were randomised in two parallel groups: a 6-week preoperative exercise training programme or standard treatment.The primary outcome measure was the composite endpoint of postoperative cardiac, pulmonary and renal complications. Secondary outcome measures were: lengths of hospital and critical care stay, APACHE II scores recorded within 6 hours postoperatively, SIRS criteria, thirty-day mortality, reoperation and postoperative bleeding. Patients were followed up for 3 months postoperatively.Study 2: was a sub-group study within Study 1.A sub-group of patients from Study 1 consented to undergo two rather than one preoperative CPETs: the first at baseline, and a second following completion of 6 weeks of exercise or on the day immediately prior to surgery. The primary outcome measure was the effect of exercise on CPET parameters.Study 3 utilised univariate and multivariate analysis to assess the value of different preoperative risk assessment tools in predicting postoperative complications in patients undergoing elective AAA repair.Results:Study 1: 136 patients were recruited, 12 withdrew before operative interventions and were not included in the analysis. A total of 124 patients (62 in each group) were included (111 men, mean (s.d.) age 73 (7) years), of which 46 patients underwent EVAR (23 in each group).14 patients (22.6 per cent) sustained postoperative complications in the exercise group, compared to 26 (41.9 per cent) in the non-exercise group (P=0.021). Four patients (3.2 per cent; 2 in each group) died within 30 days postoperatively.Length of hospital stay was significantly shorter in the exercise group (median (IQR) 7 (5-9) days) than the control group (median (IQR) 8 (6.0 - 12.3) days) (P=0.025).There were no significant differences in the length of critical care stay (P=0.845), APACHE II scores (P=0.256), incidence of re-operations (P=1.000) or postoperative bleeding (P=0.343) between the two study groups.Study 2: 48 patients were recruited: 33 patients in the exercise group, and 15 in the control group. All participants completed their two CPET assessments. A 6-week exercise schedule improved aerobic fitness parameters compared to the control group. Median (IQR) VO2 peak improved from 18.4 (15.0-20.9) to 20.0 (16.9-21.3) ml O2/kg/min; P=0.004, and median AT improved from 12.0 (10.4-14.5) to 13.9 (10.6-15.1) ml O2/kg/min; P=0.012. There were no statistically significant changes in CPET parameters in the control group.Study 3: In 124 patients undergoing elective AAA repair, lower AT (OR 0.59, 9% C.I. 0.38 to 0.89, p=0.014) and higher V-POSSUM scores (OR 1.42, 95% C.I. 1.16 to 1.75, p=0.001) were the only independent predictors of postoperative complications.A low AT was an independent predictor of cardiac complications (OR 0.59, 95% C.I. 0.36 to 0.96, p=0.034) and a high VE/VCO2 predicted pulmonary complications (OR 1.24, 95% C.I. 1.03 to 1.51, p=0.027).ConclusionPreoperative supervised exercise training appears to reduce postoperative complications and length of hospital stay in patients undergoing elective AAA repair. The mechanism appears to be an improvement in aerobic fitness preoperatively.CPET is a valuable preoperative assessment tool for elective AAA patients as it predicts organ-specific complications and may be useful in directing perioperative care

Physical activity levels in individuals after stroke

L'augmentation du niveau d'activité physique, définie comme tout mouvement corporel volontaire nécessitant une dépense d'énergie, pourrait améliorer la fonction et la santé des personnes après un accident vasculaire cérébral (AVC). L’objectif général était d’analyser le niveau d’évidences des interventions visant à augmenter le niveau d'activité physique après un AVC et de comparer l’effets d’interventions. La première étude a proposé un protocole pour une revue systématique (PROSPERO 2016: CRD42016037750) des effets d’interventions sur les niveaux d'activité physique après un AVC. La deuxième étude a consisté en une revue systématique d'essais contrôlés randomisés qui ont examiné les interventions utilisées pour augmenter les niveaux d'activité physique après un AVC. Dix-huit études ont été incluses (bons scores PEDro et très bas scores GRADE). Dans sept études, les groupes expérimentaux (aérobique seulement, résistance et entraînement à domicile; conseils, aérobie, résistance et entraînement à domicile; stimulation électrique; entraînement aux tâches fonctionnelles; thérapie assistée par robot; rétroaction basée sur accéléromètre; et encouragement à réaliser de l’activité physique) ont montré une amélioration de l'activité physique. Cependant, le petit nombre d'études et l'hétérogénéité des interventions, des mesures de résultats et des résultats ont limité les conclusions. La troisième étude a décrit un protocole d'un essai contrôlé randomisé (ClinicalTrials.gov: NCT02798237) visant à déterminer l'efficacité de l'entraînement aérobique sur l'amélioration du niveau d'activité physique et du temps consacré aux activités à faible dépense énergétique après un AVC. La quatrième étude a comparé les effets de deux interventions (essai contrôlé randomisé) de marche sur le niveau d'activité physique, le temps consacré aux activités à faible consommation d'énergie, la condition cardiorespiratoire, la dépression, l’endurance, la mobilité, la participation et la qualité de vie. Vingt-deux adultes vivant dans la communauté après un AVC chronique ont été randomisé en deux groupes. Les participants du groupe expérimental ont suivi un entraînement aérobique sur tapis roulant de 40 minutes à 60-80% de sa fréquence cardiaque de réserve, trois jours/semaine pendant 12 semaines. Les participants du groupe contrôle ont reçu la même intervention mais en limitant l’effort à 40% de la fréquence cardiaque de réserve. Il n'y a pas eu de changements significatifs sur le niveau d'activité physique ou le temps consacré aux activités à faible consommation d'énergie. Seuls les participants du groupe expérimental ont amélioré leur qualité de vie améliorée (13 points; IC95%: 3,5-23 points). Les deux groupes ont amélioré la dépression (2,2 points; IC95%: 0,01-4,3 points), leur endurance (31-55 m; IC95%: 3,8-107 m) et leur mobilité (0,12 m/s; IC95% : 0,02-0,2 m/s). Il n'y a pas eu d'autres changements significatifs. Les résultats de cette thèse ont permis de démontrer l’insuffisance d’évidences pour recommander des interventions visant à augmenter les niveaux d'activité physique des individus après un AVC. Aussi, ils nous ont amené à conclure que d’autres études sont requises pour clarifier les avantages de l'entraînement aérobique sur l'activité physique et le temps consacré aux activités à faible consommation d'énergie.The increase of physical activity levels, defined as any voluntary bodily movement that requires energy expenditure, might improve function and health in individuals after stroke. The general objective of this thesis was to analyze the current level of evidence about interventions to increase physical activity level after stroke and to develop an experimental study that could provide evidence that could help clinical practice. The first study had the objective to describe a protocol for the development of a systematic review (PROSPERO 2016: CRD42016037750) about the effects of interventions on physical activity levels after stroke. The objective of second study was to develop a systematic review of randomized controlled trials that examined which interventions have been employed for increasing physical activity levels after stroke. Eighteen studies were included (good PEDro and very low GRADE-scores). In seven studies, the experimental groups (aerobics, resistance, and home-based training; counseling, aerobics, resistance, and home-based training; electrical stimulation; functional-task training; robot-assisted therapy; accelerometer-based feedback, and physical activity encouragement) showed significant increases in physical activity. However, the small number of studies and the heterogeneity in the interventions, outcome measures, and results limit the conclusions. The third study had the objective to describe the protocol of a randomized controlled trial (ClinicalTrials.gov: NCT02798237) aimed to investigate if aerobic training is effective on improving physical activity levels and time spent in low-energy expenditure activities after stroke. The fourth study, a randomized controlled trial, aimed to investigate if aerobic training would improve physical activity levels and time spent in low-energy expenditure activities (primary outcomes), and cardiorespiratory fitness, depression, endurance, mobility, participation and quality of life (secondary outcomes) after stroke. Twenty-two community-dwelling adults with chronic stroke were randomized in two groups. The experimental group performed aerobic treadmill training at 60-80% of their heart rate reserve. The control group performed overground walking below 40% of heart rate reserve. Both groups received 40 minutes of intervention three days per week over 12-weeks. There were no significant changes on physical activity levels and time spent in low-energy expenditure activities. Compared to the controls, the experimental group showed increased quality of life (13 points; 95%CI: 3.5 to 23 points). Both groups improved depression (2.2 points; 95%CI: 0.01 to 4.3 points), endurance (31-55 m; 95%CI: 3.8 to 107 m), and mobility (0.12 m/s; 95%CI: 0.02 to 0.2 m/s). There were no other significant changes. The results of this thesis showed that the limited evidence currently available is insufficient to make a recommendation about interventions to increase physical activity levels of individuals after stroke. Further studies are needed to clarify the benefits of aerobic training on physical activity and time spent in low-energy expenditure activities.O aumento do nível de atividade física, definido como qualquer movimento corporal voluntário que requer gasto energético, pode melhorar a função e a saúde dos indivíduos após o acidente vascular encefálico (AVE). O objetivo geral dessa tese foi analisar o estado atual das evidências sobre intervenções com o objetivo de aumentar o nível de atividade física pós-AVE e desenvolver um estudo experimental que forneça evidências que possam auxiliar a prática clínica. O primeiro estudo teve como objetivo descrever um protocolo de uma revisão sistemática (PROSPERO 2016: CRD42016037750) sobre os efeitos de intervenções no nível de atividade física pós-AVE. O objetivo do segundo estudo foi realizar uma revisão sistemática de ensaios clínicos randomizados que examinaram quais intervenções foram empregadas para aumentar o nível de atividade física pós-AVE. Dezoito estudos foram incluídos (escores PEDro bons e GRADE muito baixo). Em sete estudos, os grupos experimentais (fortalecimento, exercícios aeróbios e domiciliares; aconselhamento, fortalecimento, exercícios aeróbios e domiciliares; estimulação elétrica; treino específico da tarefa; terapia robótica; feedback baseado em acelerômetro; e encorajamento à atividade física) mostraram aumento do nível de atividade física. Entretanto, o número limitado de estudos e a heterogeneidade das intervenções, dos desfechos mensurados e dos resultados limitam as conclusões. O terceiro estudo teve como objetivo descrever o protocolo de um ensaio clínico randomizado (ClinicalTrials.gov: NCT02798237) para investigar a eficácia do treinamento aeróbio na melhora do nível de atividade física e do tempo gasto em atividades de baixo consumo energético pós-AVE. O quarto estudo, um ensaio clínico randomizado, teve como objetivo investigar se o treinamento aeróbio melhora o nível de atividade física e o tempo gasto em atividades de baixo consumo energético (desfechos primários), a aptidão cardiorrespiratória, a depressão, a capacidade de caminhada, a mobilidade, a participação e a qualidade de vida (desfechos secundários) pós-AVE. Vinte e dois adultos residentes na comunidade pós-AVE crônico foram randomizados em dois grupos. O grupo experimental realizou treinamento aeróbio em esteira a 60-80% da frequência cardíaca de reserva. O grupo controle realizou caminhada no solo com intensidade inferior a 40% da frequência cardíaca de reserva. Ambos os grupos receberam 40 minutos de intervenção três dias por semana durante 12 semanas. Não houve diferença estatisticamente significativa no nível de atividade física e no tempo gasto em atividades de baixo consumo energético. Comparado ao grupo controle, o grupo experimental apresentou aumento da qualidade de vida (13 pontos; IC95%: 3,5-23 pontos). Ambos os grupos melhoraram a depressão (2,2 pontos; IC95%: 0,01-4,3 pontos), a capacidade de caminhada (31-55 m; IC95%: 3,8-107m) e a mobilidade (0,12 m/s; IC95%: 0,02-0,2 m/s). Não houve outras alterações significativas. Os resultados desta tese mostram que a evidência limitada disponível atualmente é insuficiente para fazer uma recomendação sobre intervenções para aumentar o nível de atividade física dos indivíduos pós-AVE. Ensaios clínicos futuros são necessários para determinar os benefícios do treinamento aeróbio no nível de atividade física e no tempo gasto em atividades de baixo consumo energético