Effects of cold application before subcutaneous injection of low-molecular-weight heparin on pain, bruising, and hematoma formation: A randomized controlled trial

Aims: With daily subcutaneous low-molecular-weight heparin (LMWH) injections for long periods, there is a high risk of local side effects, such as pain, bruising, and hematoma. This study aimed to compare the impact of cold application on post-injection pain, bruising, and hematoma in patients receiving subcutaneous LMWH following urologic surgery. Methods: This was a single-blind, randomized control trial. Urology inpatients were randomly assigned to three groups; Group 1: cold application for 2 min before injection, Group 2: cold application for 5 min before injection, and Group 3: control group with no cold application. Post-injection pain was assessed immediately after injection. Bruising and hematoma were assessed at 48th and 72nd hours. Results: The study included 26 patients in Group 1 (age=63.85±9.89 years; male=84.6%), 26 patients in Group 2 (age=64.54±11.66 years; male=80.8%), and 26 patients in Group 3 (age=65.65±11.36 years; male=88.5%). The pain scores in Groups 1 (11.58±12.06) and Group 2 (6.08±9.11) were lower than Group 3 (28.35±20.97) (p<0.001). At the 48th hour, the frequency of bruising in Group 1 (11.5%) and Group 2 (11.5%) was lower than that in Group 3 (38.5%) (p=0.021), and the bruise size in Group 1 (4.00±1.73 mm) was lower than that in Group 3 (15.00±7.07 mm) (p=0.020). No hematomas was detected in any patient groups at the 48th and 72nd hours. Conclusions: This study showed that although cold application for 2 or 5 minutes before injection reduced pain and bruising frequency, application for 2 minutes was more effective on bruise size.