Background Definitions for massive transfusion (MT) vary widely between studies, contributing to challenges in interpretation of research findings and practice evaluation. In this first systematic review, we aimed to identify all MT definitions used in randomised controlled trials (RCTs) to date to inform the development of consensus definitions for MT. Methods We systematically searched the following databases for RCTs from inception until 11 August 2022: MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Cumulative Index to Nursing and Allied Health Literature, and Transfusion Evidence Library. Ongoing trials were sought from CENTRAL, ClinicalTrials.gov, and World Health Organisation International Clinical Trials Registry Platform. To be eligible for inclusion, studies had to fulfil all the following three criteria: (1) be an RCT; (2) include an adult patient population with major bleeding who had received, or were anticipated to receive, an MT in any clinical setting; and (3) specify a definition for MT as an inclusion criterion or outcome measure. Results Of the 8,458 distinct references identified, 30 trials were included for analysis (19 published, 11 ongoing). Trauma was the most common clinical setting in published trials, while for ongoing trials, it was obstetrics. A total of 15 different definitions of MT were identified across published and ongoing trials, varying greatly in cut-offs for volume transfused and time period. Almost all definitions specified the number of red blood cells (RBCs) within a set time period, with none including plasma, platelets or other haemostatic agents that are part of contemporary transfusion resuscitation. For completed trials, the most commonly used definition was transfusion of ≥ 10 RBC units in 24 h (9/19, all in trauma), while for ongoing trials it was 3–5 RBC units (n = 7), with the timing for transfusion being poorly defined, or in some trials not provided at all (n = 5). Conclusions Transfusion of ≥ 10 RBC units within 24 h was the most commonly used definition in published RCTs, while lower RBC volumes are being used in ongoing RCTs. Any consensus definitions should reflect the need to incorporate different blood components/products for MT and agree on whether a ‘one-size-fits-all’ approach should be used across different clinical settings.

No standardized or universally accepted definition for massive transfusion (MT) currently exists, making it difficult to compare safety and efficacy data across studies on critically bleeding patients. The Bleeding Academic Research Consortium successfully standardized definitions for major bleeding in both surgical and non-surgical patients, providing proof of principle for a similar approach to be adopted for the definition of MT.

Colitis caused by vasculitis is a rare and poorly understood pathology. Little evidence exists on its clinical presentation, path to diagnosis, and surgical management. In this report, we present a case report and literature review. A healthy 20-year-old male patient presented with hemorrhagic colitis requiring total colectomy with end ileostomy. Pathological examination showed pancolitis with multiple ulcers, transmural inflammation, hemorrhage, and microvascular thrombosis. Extensive serological testing revealed elevated cytoplasmic antineutrophil cytoplasmic antibody (c-ANCA) and eosinophilia, leading to a diagnosis of eosinophilic granulomatosis with polyangiitis (EGPA) and vasculitis-induced colitis. A literature review was subsequently conducted. Nineteen studies were found documenting vasculitis-induced colitis in the absence of inflammatory bowel disease (IBD). Systemic signs of vasculitis, hemorrhagic colitis, and progression to fulminant colitis were present. Of all patients, 40.0% required colorectal surgery and 62.5% of those patients received a stoma; 25% underwent emergency surgery following failed immunosuppression. All cases relied on clinical correlation with serology and/or histopathology to reach a final diagnosis. We report a case of vasculitis-induced colitis caused by c-ANCA− positive EGPA. The review shows that vasculitis-induced colitis without IBD is an important differential that clinicians should be aware of in patients presenting with colitis.