Exploring the experiences and perspectives of substitute decision-makers involved in decisions about deceased organ donation: a qualitative study protocol.

INTRODUCTION: In Canada, deceased organ donation provides over 80% of transplanted organs. At the time of death, families, friends or others assume responsibility as substitute decision-makers (SDMs) to consent to organ donation. Despite their central role in this process, little is known about what barriers, enablers and beliefs influence decision-making among SDMs. This study aims to explore the experiences and perspectives of SDMs involved in making decisions around the withdrawal of life-sustaining therapies, end-of-life care and deceased organ donation. METHODS AND ANALYSIS: SDMs of 60 patients admitted to intensive care units will be enrolled for this study. Ten hospitals across five provinces in Canada in a prospective multicentre qualitative cohort study. We will conduct semistructured telephone interviews in English or French with SDMs between 6 and 8 weeks after the patient's death. Our sampling frame will stratify SDMs into three groups: SDMs who were not approached for organ donation; SDMs who were approached and consented to donate and SDMs who were approached but did not consent to donate. We will use two complementary theoretical frameworks-the Common-Sense Self-Regulation Model and the Theoretical Domains Framework- to inform our interview guide. Interview data will be analysed using deductive directed content analysis and inductive thematic analysis. ETHICS AND DISSEMINATION: This study has been approved by the Centre Hospitalier de l'Université de Montréal Research Ethics Board. The findings from this study will help identify key factors affecting substitute decision-making in deceased organ donation, reasons for non-consent and barriers to achieve congruency between SDM and patient wishes. Ultimately, these data will contribute to the development and evaluation of tools and training for healthcare providers to support SDMs in making decisions about organ donation. TRIAL REGISTRATION NUMBER: NCT03850847.

Initial Dietary Protein Intake Influence Muscle Function Adaptations in Older Men and Women Following High-Intensity Interval Training Combined with Citrulline.

BACKGROUND: This study evaluates whether the initial amount of dietary protein intake could influence the combined effect of high-intensity interval training (HIIT) and citrulline (CIT), or HIIT alone, on body composition, muscle strength, and functional capacities in obese older adults. METHODS: Seventy-three sedentary obese older men and women who completed a 12-week elliptical HIIT program with double-blinded randomized supplementation of CIT or placebo (PLA) were divided into four groups according to their initial protein intake (CIT-PROT+: n = 21; CIT-PROT-: n = 19; PLA-PROT+: n = 19; PLA-PROT-: n = 14). Body composition (fat and fat-free masses), handgrip (HSr) strength, knee extensor (KESr) strength, muscle power, and functional capacities were measured pre-intervention and post-intervention. RESULTS: Following the intervention, the four groups improved significantly regarding all the parameters measured. For the same initial amount of protein intake, the CIT-PROT- group decreased more gynoid fat mass (p = 0.04) than the PLA-PROT- group. The CIT-PROT+ group increased more KESr (p = 0.04) than the PLA-PROT+ group. In addition, the CIT-PROT- group decreased more gynoid FM (p = 0.02) and improved more leg FFM (p = 0.02) and HSr (p = 0.02) than the CIT-PROT+ group. CONCLUSION: HIIT combined with CIT induced greater positive changes than in the PLA groups. The combination seems more beneficial in participants consuming less than 1 g/kg/d of protein, since greater improvements on body composition and muscle strength were observed.

Muscle Strength and Body Weight Mediate the Relationship Between Physical Activity and Usual Gait Speed.

BACKGROUND: Usual gait speed (UGS) is recognized as a good indicator of a variety of health conditions as well as a predictor of future disability and mortality. There is evidence that UGS increases with physical activity. Muscle function and body composition changes may mediate these changes. However, we do not know exactly which of these factors contribute to the effect of physical activity on gait speed or the magnitude of their contribution. METHODS: Data are from 1378 women aged 75 years and older recruited in the Toulouse EPIDémiologie de l'OStéoporose cohort. Body weight and composition (dual energy X-ray absorptiometry), knee extension strength, and physical activity habits were assessed. The INDIRECT macro for SPSS (SPSS Inc, Chicago, IL) was used to determine total and specific indirect effects of physical activity on UGS through body weight (BW) and composition as well as muscle mass and strength. RESULTS: Knee extension strength [95% confidence interval (CI) 0.0091, 0.0231] and BW (95% CI 0.0037, 0.0412), but not fat mass or muscle mass, were mediators of the relationship between physical activity and gait speed. However, muscle mass significantly mediated the relationship between physical activity and muscle strength (95% CI -3.0722, -0.6265). CONCLUSIONS: Results suggest that muscle strength and BW are the most significant mediators of the relationship between physical activity and UGS. Although the specific effect of muscle mass appears negligible at first sight, its role should not be overlooked given its impact on muscle strength.