Sendir 2015

Methods	Randomised parallel controlled trial
Participants	Baseline: 60 participants were divided into 3 groups. We reported the results of 20 participants in the 10‐second heparin injection group and 20 participants in the 30‐second heparin injection group ‐ 13 male and 27 female; mean age in the intervention group was 62.7 (SD 8.83) years and in the control group 57.9 (SD 12.5) years. Setting: patients who were hospitalised in the orthopedic wards of a university hospital in Turkey Country: Turkey Injection site: LMWH was injected SC into the tissue of the lower abdominal wall (umbilical region) Injection protocol: insertion angle 90°, grasping of tissue at injection site, injection without drug aspiration Inclusion criteria: 18 years of age or older, received SC injections of LMWH once a day, had normal platelet values, were conscious, did not have any complications in the perioperative days, did not have acute painful disease Exclusion criteria: were pregnant, had abnormalities of coagulation or haematologic and allergic diseases, received any other injections at the abdominal site during the days of the research, had any incision or scar tissue at the abdominal site
Interventions	Slow injection (30 seconds) vs fast injection of heparin (10 seconds)
Outcomes	Site pain intensity was assessed by VAS (0 to 100 mm) immediately, and at 48, 60, and 72 hr after injection. Injection site bruising was evaluated at 48, 60, and 72 hr after each injection with a transparent mm ruler to measure the surface area of the bruise and record it as mm2.
Notes	Study authors were contacted about any use of anticoagulant drugs; they reported that participants were excluded if participants took any anticoagulant drugs before the start of the study. Funding sources: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "A computerized randomisation program was used to allocate the patients."
Allocation concealment (selection bias)	Unclear risk	Method not stated
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "non‐blinded study design was used."
Blinding of outcome assessment (detection bias) All outcomes	High risk	Quote: "non‐blinded study design was used."
Incomplete outcome data (attrition bias) All outcomes	High risk	6.25% dropout after randomisation in the intervention group, as 4 participants were hospitalised in intensive care unit after randomisation. Use of intention‐to‐treat analysis was not reported.
Selective reporting (reporting bias)	Low risk	All stated outcomes were reported.
Other bias	Unclear risk	Other aspects of heparin injection (e.g. heparin temperature, syringe size, injection volume, air bubble in the syringe) were not clearly described. This may have affected study outcomes.