Clinical Research Directory

Inclusion Criteria: * Patient age ≥ 18 years * Patient managed in pre-hospital setting for a ST elevation myocardial infarction (STEMI) : Chest pain \< 12 hours with moderate to severe pain (VAS \> 6/10) or STEMI on ECG according to 2017 ESC guidelines Exclusion Criteria: * Previous analgesic treatment for this episode of chest pain * Hypersensitivity to morphine, methoxyflurane, any fluorinated anesthetic or any of the excipients listed in SmPC, * Decompensated respiratory failure (in the absence of artificial ventilation), * Severe hepatocellular insufficiency (with encephalopathy), * Acute head trauma and intracranial hypertension in the absence of controlled ventilation, * Uncontrolled epilepsy, * Treatment with buprenorphine, nalbuphine and pentazocine, naltrexone, nalmefene or sodium oxybate, * Breastfeeding, in case of initiation or continuation after birth of a long-term treatment. * Known malignant hyperthermia or genetic predisposition of the patient. * History of serious adverse effects of the patient or his family after administration of inhaled anesthetics. * History of signs of liver damage after use of methoxyflurane or after anesthesia with a halogenated hydrocarbon. * Clinically significant renal impairment. * Known renal failure with creatinine clearance below 30 ml/min or undergoing extracorporeal renal replacement therapy. * Altered level of consciousness due to any cause, including head trauma, drug or alcohol use. * Clinical evidence of cardiovascular instability (PAS \<90 mm Hg). * Clinical evidence of respiratory depression. * Incapacity to self-assess pain intensity * Incapacity to methoxyflurane self-administration * Known pregnancy, breastfeeding, minors or incapacity (curatorship or guardianship) * Participation in another interventional study involving human participants or being in the exclusion period at the end of a previous study involving human participants * Absence of a Social Security