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Evidence-based patient blood management guidelines commonly recommend restrictive haemoglobin thresholds of 70 to 80g/L for asymptomatic adults. However, most transfusion trials have enrolled adults across a broad age span, with few exclusive to older adults. Our recent meta-analysis of transfusion trials that focussed on older adults paradoxically found lower mortality and fewer cardiac complications when these patients were managed using higher haemoglobin thresholds. We postulate that declining cardiac output with age contributes to deteriorating oxygen delivery capacity which impacts anaemia-associated outcomes in older adults and propose a model to explain this age-related difference.We reviewed evidence concerning the pathophysiology of ageing to explore the disparity in transfusion trial outcomes related to haemoglobin thresholds in different age groups. The literature was searched for normative cardiac output values at different ages in healthy adults.Using normative peak cardiac output data, we modelled oxygen delivery capacity in young, middle-aged and older adults at a range of haemoglobin levels.Cardiovascular and pulmonary systems are impacted by age-related pathophysiological changes. Diminishing peak cardiac associated with ageing output reduces the maximal oxygen delivery achievable under metabolic stress. Hence, at low haemoglobin levels, older adults are more susceptible to tissue hypoxia than younger adults. Our model predicts that an older adult with a haemoglobin of 100 g/L has a similar peak oxygen delivery capacity to a young adult with a haemoglobin of 70 g/L. Age-related pathophysiological changes provide some explanation as to why older adults have a lower tolerance for anaemia than younger adults. This indicates the need for patient blood management haemoglobin thresholds specific to older as distinct from younger adults.

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Restrictive transfusion practice is widely promoted, with many international guidelines recommending haemoglobin thresholds of 70 to 80 g/l for adult patients who are asymptomatic. Randomized controlled trials comparing outcomes associated with liberal and restrictive transfusion strategies underpin this approach. Meta‐analyses including trials of adult patients >18 years of age have concluded that restrictive practice is noninferior to liberal transfusion approaches. A restrictive approach to transfusion reduces resource consumption and cost, as well as the hazards associated with unnecessary exposure to blood products. Although adults aged ≥65 years consume over half of the blood supply, there are few randomized controlled transfusion trials exclusive to this cohort. Our 2017 meta‐analysis of a small number of trials focussed on older adults found that higher transfusion haemoglobin thresholds were associated with lower mortality and fewer cardiac complications in this age group. Other studies have also shown that higher transfusion haemoglobin thresholds are beneficial in older adults. This paper presents recent evidence regarding transfusion outcomes in older adults and discusses aspects of the pathophysiology of ageing that impact on the reduced resilience of older patients to anaemic states. This evidence challenges the use of Hb thresholds that apply across the adult lifespan, regardless of age. It proposes that older age be considered as a risk factor in assessing transfusion requirements, and that transfusion practice in older adults may require higher haemoglobin thresholds than for younger adults.

Objective This research aims to elucidate drivers of blood use in an older population, with a focus on unplanned transfusions following ED presentation. Methods In a retrospective cohort study we examined 2015 data for ED presentations and blood use in two hospitals serving a population containing a high proportion (21%) of adults aged ≥65 years. Unplanned blood use was defined as any transfusion ≤24 h of presentation. Data were analysed by age, sex, Major Diagnostic Category, triage category and time to transfusion. Results A total of 5294 blood components were transfused, comprising red cells (n = 3784), fresh frozen plasma (n = 657), platelets (n = 563) and cryoprecipitate (n = 290). Men aged ≥65 years were the highest users (40%, 2107 components). Unplanned transfusions accounted for 28% (n = 1057) of annual red cell use. Of 85 014 ED presentations, 494 (0.6%) were associated with unplanned red cell transfusion. Four Major Diagnostic Categories accounted for 81% (n = 853) of unplanned red cell use: gastrointestinal (n = 375), haematology (n = 267), trauma (n = 144) and cardiovascular (n = 67). Over one‐fifth of unplanned transfusions (21%, n = 222 of 1057) were associated with ICD‐10 codes for anaemia as a reason for presentation within the Haematology Major Diagnostic Category. Adults aged ≥65 years accounted for 62% of overall red cell use and 61% of transfusions ≤24 h of presentation. Odds of unplanned red cell transfusion increased with age, peaking at odds ratio 28.5 (95% confidence interval 14.2–57.4) in those aged 85 years and above. Conclusions Unplanned blood use accounted for 28% of annual hospital blood consumption. Blood component use increased with age and was greatest in older men. A significant burden of anaemia treatment was identified by the ED.