To observe the efficacy and safety of hydromorphone in the treatment of acute chest pain, and to explore the potential advantages of hydromorphone for analgesia in patients with acute chest pain, so as to provide more theoretical basis for individualized analgesia and rapid recovery in patients with acute chest pain.

Inclusion criteria:

1. Age 18-64 years old;
2. Gender is not limited;
3. Patients with acute chest pain, with the time from pain onset to visit the doctor ≤ 24 days;
4. Severe pain that requires the use of opioids to control as determined by emergency physicians;
5. Obtain informed consent from the patient or family members.

Exclusion criteria:

1. Known allergy to hydromorphone or morphine;
2. Systolic blood pressure <100 mmHg, oxygen saturation <95%, pulse less than 60 beats/min;
3. Use of acetaminophen or nonsteroidal anti-inflammatory drugs in the past 8 hours;
4. Chronic pain, defined as pain lasting for more than 12 weeks;
5. Delirium, alcohol withdrawal symptoms or other drug intoxication;
6. Pregnant or lactating women;
7. Patients with mental or neurological diseases, cognitive and consciousness disorders and inability to express correctly;
8. Participating in any other research at the same time;
9. Factors that increase the risk of participating in the study (life-threatening chest pain patients who require rapid diagnosis or treatment intervention, such as resuscitation status, excluding chest pain caused by myocardial infarction), who are judged by the researchers to be unsuitable for inclusion in the study.