Comparison of Low-cost Interventions for Pain Reduction During Radial Artery Puncture in the Emergency Department: A Three-arm Randomized Controlled Trial

Inclusion Criteria: * Patients aged 18 years or older, who present to the emergency department of Queen Savang Vadhana Memorial Hospital that requires arterial blood sampling procedure for diagnostic purposes Exclusion Criteria: * Altered level of consciousness (Glasgow Coma Scale \< 15) * Cognitive impairment or communication barriers precluding accurate pain assessment (e.g., severe dementia, aphasia, intoxication, delirium) * Contraindications to radial artery cannulation (e.g., severe peripheral vascular disease, history of arteriovenous fistula at the puncture site, active infection at the puncture site) * Pregnancy * Need for emergency management which any delay could worsen patient care (e.g., cardiac arrest, respiratory failure requiring immediate intubation) * Known allergy or hypersensitivity to lidocaine or amide-type local anesthetics * Severe pain from other sources that could distracting pain assessment related to the arterial blood sampling procedure (e.g., significant trauma, bone fractures, severe burns) * Failure to obtain successful arterial access after two attempts by an experienced operator.