Data collection and interventions
NRS, pain
Before the first intervention, informed and written consent was obtained from the patients, and the pain rating scale was trained. The first needle insertion was considered the primary intervention for all patients, and the vascular access procedure was performed without any intervention. The pain score was determined and recorded one minute after needle insertion by the Numerical Rating Scale (NRS). Each patient received one of the interventions in the next HD session (2 days later), including cooling spray (ethyl chloride), 10% lidocaine spray, or placebo spray. Patients who first received a cooling spray (i.e., 2 days after the initial non-intervention needle insertion) received lidocaine spray 2 weeks later and placebo spray 4 weeks later. Patients who first received lidocaine spray received the placebo spray 2 weeks later and the cooling spray 4 weeks later. Patients who first received placebo spray received cooling spray 2 weeks later and lidocaine spray 4 weeks later [
The design of the studyIn the case of using a cooling spray, after disinfecting the skin, the spray was sprayed on the skin for 3 to 4 s at a distance of 15 to 20 cm, allowing the spray to evaporate from the skin for 10 s, and vascular access occurred after the disinfection of skin [A particular container for lidocaine spray was emptied, washed, and filled with drinking water to prepare the placebo spray. All three sprays’ exterior parts were covered with paper to look almost identical. In all three cases, 1 min after vascular access, the patient’s pain score was determined by asking the patient and using the NRS [