Methods	Randomisation was carried out in blocks of 10 and was stratified for repair of abdominal aortic aneurysm (AAA) or aorto-femoral bypass for occlusive disease. Patients were randomised by drawing a sealed envelope that contained a prescription for either desmopressin (DDAVP) or placebo. The method used to generate allocation sequences was not described. The only person to have knowledge of treatment assignment was the pharmacist, who kept records and prepared the DDAVP or placebo in identical-appearing plastic bags of 50 ml normal saline solution
Participants	91 male patients undergoing elective aortic surgical operations were randomly assigned to one of two groups Desmopressin (DDAVP) group: n = 43; mean age (+/−SD) = 62 (9) years. Placebo group: n = 48; mean age (+/−SD) = 64 (8) years.
Interventions	DDAVP group received 20 ug of DDAVP intravenously for 15 minutes immediately after IV heparisation with 100 units/kg and just before aortic cross-clamp application was performed. Placebo group received 0.9% normal saline. NB: Both groups were exposed to autotransfusion and cell salvage
Outcomes	Number of patients transfused allogeneic blood (n) Amount of allogeneic blood transfused (units) Blood loss (mls) Mortality (n) Myocardial infarction (n) Deep vein thrombosis (n) Pulmonary embolus (n) Acute limb ischemia (n) Bowel infarction (n)
Notes	Quality assessment score (Schulz criteria): 5/7 Transfusion protocol not described.
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Unclear	Method of randomisation was not described.
Allocation concealment?	No	C - Inadequate. Allocation concealment was by means of sealed envelopes
Blinding? All outcomes	Yes	Double blind.