Evaluation of interventions to prevent vasovagal reactions among whole blood donors: rationale and design of a large cluster randomised trial.

BACKGROUND: Vasovagal reactions (VVRs) are the most common acute complications of blood donation. Responsible for substantial morbidity, they also reduce the likelihood of repeated donations and are disruptive and costly for blood services. Although blood establishments worldwide have adopted different strategies to prevent VVRs (including water loading and applied muscle tension [AMT]), robust evidence is limited. The Strategies to Improve Donor Experiences (STRIDES) trial aims to reliably assess the impact of four different interventions to prevent VVRs among blood donors. METHODS: STRIDES is a cluster-randomised cross-over/stepped-wedge factorial trial of four interventions to reduce VVRs involving about 1.4 million whole blood donors enrolled from all 73 blood donation sites (mobile teams and donor centres) of National Health Service Blood and Transplant (NHSBT) in England. Each site ("cluster") has been randomly allocated to receive one or more interventions during a 36-month period, using principles of cross-over, stepped-wedge and factorial trial design to assign the sequence of interventions. Each of the four interventions is compared to NHSBT's current practices: (i) 500-ml isotonic drink before donation (vs current 500-ml plain water); (ii) 3-min rest on donation chair after donation (vs current 2 min); (iii) new modified AMT (vs current practice of AMT); and (iv) psychosocial intervention using preparatory materials (vs current practice of nothing). The primary outcome is the number of in-session VVRs with loss of consciousness (i.e. episodes involving loss of consciousness of any duration, with or without additional complications). Secondary outcomes include all in-session VVRs (i.e. with and without loss of consciousness), all delayed VVRs (i.e. those occurring after leaving the venue) and any in-session non-VVR adverse events or reactions. DISCUSSION: The STRIDES trial should yield novel information about interventions, singly and in combination, for the prevention of VVRs, with the aim of generating policy-shaping evidence to help inform blood services to improve donor health, donor experience, and service efficiency. TRIAL REGISTRATION: ISRCTN: 10412338. Registration date: October 24, 2019.

Healthy snacks in hospitals: Testing the potential effects of changes in availability.

BACKGROUND: Hospitals offer snacks for sale to patients, staff and visitors. AIM: As food choice is heavily influenced by the options available, the present study (a) audited snack availability and purchase in NHS hospital sites across a large UK city; and (b) tested the potential effects of changes to this availability in an online choice experiment. METHODS: In Study 1 (audit), single-serve snacks (n=376) available in 76 hospital food retail units were audited. Purchasing data were obtained from six food retail units over four weeks (27,989 sales). In Study 2 (online experiment), participants (n=159) chose snacks from pictured ranges containing 25% (minority), 50% (equivalent) or 75% (majority) healthy options. RESULTS: Available single-serve snacks varied markedly in calorie (18-641 kcals), fat (0-39 g), sugar (0.1-76 g) and salt (0-2.9 g). Only 30% of available snacks were healthy options and only 25% of the most commonly purchased snacks were healthy options. In Study 2, snack choice was significantly associated with the availability of healthy options in the choice array (X2 (2)= 59.71, p<.01). More participants made healthy choices when product ranges contained 75% healthy options compared to 50% (p<.01) and 50% healthy options compared with 25% (p<.01). CONCLUSIONS: Healthy snacks are readily available in NHS sites but there is a greater relative variety of unhealthy snack products. Many consumers continue to purchase unhealthy items. Further increasing the availability and variety of healthy options may support consumers to make healthier choices.