Thromboembolism is a frequently seen complication in patients who undergo long-term movement restriction and undergo surgical intervention, causing serious consequences such as pulmonary embolism . For this reason, heparin is frequently used for protective or therapeutic purposes in clinical situations where there is a risk of venous thromboembolism or thromboembolytic events . In the 1980s, low molecular weight heparin (LMWH) preparations, often administered subcutaneously (SC), were developed in order to increase the desired effect and reduce the side effects of heparin applications . It is stated in the literature that SC injection applications can be safely injected into the outer-lateral side of the upper arm, anterior aspect of the thigh, under the scapula and abdominal region . However, in the literature, it is emphasized that ecchymosis and hematoma formation is more common in SC LMWH applications, especially in the arm and thigh areas after SC injection. Therefore, in LMWH applications, it is stated that abdominal region is the most reliable injection site because it has thicker SC tissue compared to other parts of the body . In summary studies, it is recommended as the preferred site for LMWH applications due to the excess of SC fat tissue in the abdominal region, its width to allow rotation of the injection site and the lack of muscle activity .

Systemic and local complications may occur due to heparin injection by SC route. The most important local complications are; ecchymosis at the injection site, hematoma formation and local pain formation at the injection site . In this study, the frequency of ecchymosis; Kuz and Uçar (2001) 11.4%, Dursun and Balcı Akpınar (2014) 28.7%, Küçükgüçlü and Okumuş (2010) 31%, Varghese et al. (2006) 36%, Palese (2013) 38%, Yildirim and Atalay (2005) 57%, Zaybak and Khorshid (2008) reported as 64%. These treatment-related complications complicate the use of the damaged area in subsequent injections, adversely affect drug absorption, and cause physical trauma (ecchymosis, hematoma and pain) and changes in body image.

Pain is a subjective experience that can occur in very different qualities and severity. Pain experienced due to injection is generally defined as a condition that occurs as a result of mechanical trauma in the tissue and stimulates the nerve fiber ends with the entry of the needle into the tissue. Due to the presence of pain receptors in SC tissue, patients often experience discomfort and pain during and after LMWH applications. Pain during injection significantly affects the patient's non-compliance to treatment and pain after injection significantly affects the comfort and life activities of the patient by restricting the use of the extremity . One of the methods used to prevent these negative complications is cold applications.

Local cold administration reduces blood flow through vasoconstriction of the arterioles, controls bleeding and reduces ecchymosis and hematoma development . In addition, local cold application provides vasoconstriction in the tissue to which it is applied, slows blood flow and increases the viscosity of the blood, limits edema and inflammatory process, controls bleeding by reducing capillary permability, and reduces pain perception . With this localized sensory effect, attention is directed towards cold from pain, and thus pain is alleviated by the anesthetic effect of cold . In the studies carried out on the subject; It has been reported that 5 minutes of local humid cold application after SC injection results in a reduction in the severity and pain rate of ecchymosis . Küçükgüçlü and Okumuş (2010); SC indicated that two minutes of ice application to the heparin administration site before and after administration was an effective method of reducing ecchymosis and hematoma. Avşar and Kaşıkçı (2013); They found that two minutes of cold application to the SC injection site reduced ecchymosis and pain. Şendir et al. (2015) SC injection time of 30 seconds and 5 minutes before and after the injection of local ice application, effective in reducing the intensity of pain and ecchymosis was reported to be effective. Similarly, Korkmazcan (2016) emphasizes that application of local ice to the skin is effective for reducing ecchymosis, hematoma and pain in SC LMWH injections. In addition, it is reported that pre-injection coolant spray and thermo-mechanical analgesia method reduce pain intensity in LMWH applications via SC .

SC injection applications are an important part of drug applications and are frequently performed by nurses in clinical practice. Complications resulting from these applications cause physical and mental trauma in patients, they are reluctant to make the next injection, and for nurses, ecchymosis, hematoma and pain occurring at the injection site play a restrictive role in the selection of the site. This is an important problem for patients receiving heparin treatment for a long time; It is seen that different cold application methods such as ice application, cooling spray and thermo-mechanical analgesia techniques are used in heparin injections by SC route. However, there is no study on which these methods are used together and the effects of these methods are compared. This work; The aim of this study was to investigate the effect of three different cold application methods on ecchymosis and pain formation at the injection site in patients undergoing LMWH injection via SC.