This study will be conducted to evaluate the effect of the Traction, Pressure, and Rapid Muscle Release (TPR) technique, an innovative method used during intramuscular vitamin B12 (cyanocobalamin) injections, on patients' pain and satisfaction levels compared with the conventional injection method.

Intramuscular (IM) drug injection is one of the most commonly used invasive medication administration methods performed under the responsibility of a licensed nurse in all healthcare settings where patients receive care. Medications administered via the IM route are often preferred because they allow faster drug absorption compared with oral or subcutaneous administration and enable the safe administration of irritating medications. The most frequently administered drug groups via the IM route include vaccines, hormones, vitamins, and antibiotics. Since IM injections are routinely performed by nurses as part of daily treatment practices, the procedure is often considered a simple technique. However, if IM injections are not performed correctly and carefully, serious complications may occur. Potential complications associated with IM injections include abscess, pain, cellulitis, tissue damage, hematoma, nerve injury, muscle fibrosis, and necrosis. Among these complications, pain is the most commonly reported. Studies have indicated that patients often perceive pain associated with intramuscular injections as one of the most severe types of pain, which may lead to the development of significant fear in patients. Inadequate management of pain during injection procedures may lead to the development of injection-related fear and non-adherence to treatment and care, which may eventually result in delayed care and treatment, needle phobia, and avoidance of healthcare services. Pain management is a fundamental component of nursing care and is considered both a legal and ethical responsibility of nurses. Moreover, reducing pain associated with IM injections can strengthen the patient-nurse relationship, increase patient satisfaction, and improve cooperation during care. For painless and comfortable IM injections, it is important to follow safe injection practices such as selecting the appropriate injection site, patient position, and needle length; using the double-needle technique; applying sterile technique; injecting the medication slowly; and distracting the patient. However, despite these precautions, some patients may still experience pain during IM injection procedures. Therefore, pharmacological and non-pharmacological methods may be used to reduce pain. Among the pharmacological methods commonly used to reduce pain are topical anesthetic agents and cold spray applications. However, the use of topical anesthetics is limited due to the risk of systemic toxicity, local complications, and their relatively slow and weak analgesic effects. Currently, in addition to pharmacological treatments, various non-pharmacological methods such as massage, pressure, local cold-heat application, acupressure, Buzzy, and ShotBlocker devices are also used in the management of pain associated with IM injections. Nevertheless, not all of these interventions are practical, quick to apply, or cost-effective. Therefore, there is a need for easy-to-use, rapid, and cost-effective methods to reduce pain associated with IM injections. One of the recently introduced techniques is the Traction, Pressure, and Rapid Muscle Release (TPR) technique. In the TPR technique, after identifying the injection site within the muscle tissue, the skin layers are pulled using the thumb and index finger while the needle is held at a 90° angle. Then, deep pressure is applied to the muscle with the same two fingers simultaneously, after which the pressure is rapidly released, and the medication is injected quickly. The mechanism of the TPR technique is based on the gate control theory of pain. In this method, skin traction and deep pressure applied to the muscle simultaneously with the injection activate large-diameter, low-threshold mechanoreceptive nerve fibers (thick A-beta fibers). This activation facilitates the closure of the pain gate at the spinal cord level, thereby reducing the perception of pain. Studies conducted using the TPR method have reported reduced pain levels among patients. A review of the literature shows that only two studies have investigated this innovative, simple, and cost-effective technique, and it has been recommended that the method be tested in different sample groups and cultural contexts. In this context, the present study was planned as a randomized controlled experimental study to determine the effect of the TPR technique applied during intramuscular injections on patients' pain and satisfaction levels among patients presenting to the emergency department of a public hospital in Türkiye.

This study will be conducted using a post-test control group randomized controlled experimental design. The sample of the study will consist of patients who present to the emergency department of a hospital to receive intramuscular (IM) cyanocobalamin (vitamin B12) injection, who voluntarily agree to participate in the study, and who meet the inclusion and exclusion criteria. Patients to be included in the study sample will be randomly assigned to the experimental and control groups according to the last digit of the protocol number given to them at the time of hospital admission. The sample size of the study was calculated by power analysis. The sample size was determined using the G*Power 3.1.9.7 program with the t-test for the difference between two independent means. In the analysis, 80% statistical power, a 95% confidence level (1-α), an effect size of f = 0.50, and a one-tailed hypothesis assumption were considered. As a result of the calculation, the minimum sample size was determined as 102 participants (experimental: 51; control: 51). Accordingly, in the study, 51 patients in the experimental group will receive cyanocobalamin injection using the TPR injection technique, while 51 patients in the control group will receive cyanocobalamin injection using the conventional injection technique. The data obtained from the study will be analyzed using the SPSS (Statistical Package for the Social Sciences) 29.0 software package. Data will be collected using the "Patient Information Form," "Visual Analog Scale (VAS) - Pain," and "Visual Analog Scale (VAS) - Satisfaction."

Inclusion Criteria:

• Voluntary participation in the study
• Ability to speak and understand Turkish
• Being between 18 and 65 years of age
• Having a body mass index (BMI) between 18.5 and 30
• No sensory impairment in the ventrogluteal muscles

Exclusion Criteria:

• Presence of a scar, burn, redness, hematoma, bruising, tenderness, or induration at the injection site
• History of intramuscular injection in the ventrogluteal region within the last 15 days
• Presence of injection-related fear
• Diagnosis of Diabetes Mellitus
• History of neuropathy
• Presence of any hearing, visual, or speech impairment
• Presence of a mental disability
• Use of oral or parenteral analgesic medication before the procedure.

The data of the patients included in this study are not publicly available due to confidentiality considerations but are available from the corresponding author upon reasonable request.

Participants: Patients included in the study will be blinded to the injection technique used.

Outcomes Assessor: All injections administered to patients in the experimental and control groups will be performed by a nurse who is a member of the research team. However, an independent nurse who is not involved in the research will be responsible for assessing the outcome measures obtained from the patients immediately after the procedure. This nurse will also be blinded to the study groups.