Association between preoperative haemoglobin concentration and cardiopulmonary exercise variables: a multicentre study

Background: Preoperative anaemia and low exertional oxygen uptake are both associated with greater postoperative morbidity and mortality. This study reports the association among haemoglobin concentration ([Hb]), peak oxygen uptake (V_O2 peak) and anaerobic threshold (AT) in elective surgical patients. Methods: Between 1999 and 2011, preoperative [Hb] and cardiopulmonary exercise tests were recorded in 1,777 preoperative patients in four hospitals. The associations between [Hb], V_O2 peak and AT were analysed by linear regression and covariance. Results: In 436 (24.5%) patients, [Hb] was <12 g dl-1 and, in 83 of these, <10 g dl-1. Both AT and V_O2 peak rose modestly with increasing [Hb] (r2 = 0.24, P <0.0001 and r2 = 0.30, P <0.0001, respectively). After covariate adjustment, an increase in [Hb] of one standard deviation was associated with a 6.7 to 9.7% increase in V_O2 peak, and a rise of 4.4 to 6.0% in AT. Haemoglobin concentration accounted for 9% and 6% of the variation in V_O2 peak and AT respectively. Conclusions: To a modest extent, lower haemoglobin concentrations are independently associated with lower oxygen uptake during preoperative cardiopulmonary exercise testing. It is unknown whether this association is causative

What motivates children to play outdoors? Potential applications for interactive digital tools

Copyright 2014 ACM. Children (8-12 years) living in urban, western contexts are increasingly spending their free time indoors engaging in digital recreation, rather than outdoor, child-directed play. There is potential for place-specific, digital technology to be designed to motivate children 'off the couch' and outdoors into their local natural places. This paper presents the outcomes of three workshops conducted with eleven children (8-12 years) in Aalborg, Denmark, designed to understand key motivators for outdoor play in children. Children were divided into five design groups. Fictional inquiry and a series of artifacts and triggers were used to communicate the design task to children and inspire a range of relevant designs. Here, we report on the design outcomes of workshops, the motivators for outdoor play, and potential applications for interactive digital technology to inspire more regular, outdoor play experiences in children