Zaybak 2008

Methods	Design: randomised self‐controlled trial
Participants	Baseline: 50 participants ‐ 25 male and 25 female; mean age of participants was 55.25 (SD 12.37) years Setting: patients who were hospitalised in the neurology, orthopaedics, and cardiology units of a university hospital in Izmir, Turkey Country: Turkey Injection site: right or left side of abdomen Injection protocol: insertion angle 90°, grasping the tissue of the injection site, injection without drug aspiration Inclusion criteria: received SC injection of LMWH, were conscious, platelet values were within normal limits before the trial started Exclusion criteria: were pregnant; had haematological disease, abnormal coagulation, or any allergic disease; received any other injections at the abdominal site during the trial, had any incision or scar tissue at the abdominal site
Interventions	Slow injection (30 seconds) versus fast injection of heparin (10 seconds) Time between 2 injections was 12 hr.
Outcomes	Site pain intensity was assessed by VAS (0 to 100 mm) immediately after injection. Injection site bruising was evaluated at 48 and 72 hr after each injection with millimetric measuring paper to measure area of the bruise recorded as mm2.
Notes	Study authors were contacted, but no response was received. Funding sources: Research Foundation of Ege University, Izmir, Turkey
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation was reported but how sequence was generated was not described. Quote: "Each of participant randomised into intervention or control group according to treatment order."
Allocation concealment (selection bias)	Unclear risk	Method not stated
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding of participants and personnel was impossible in this trial.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Quote: "Another rater who was blind to the research operated the stop‐watch to determine the pain period." Assessor blinding for measurement of bruise was not reported.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No dropouts or losses to follow‐up
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, needle gauge, injection volume, air bubble in the syringe) were not clearly described. This may have affected outcomes.