Angina pectoris emergency first aid guide: scientific dosage of nitroglycerin and home coping strategies

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The 2022 "China Cardiovascular Disease Report" shows that there are more than 2 million new angina patients in my country each year. Nitroglycerin is a key emergency drug. Proper use can reduce the risk of myocardial infarction by 70%. However, clinical data show that 38% of patients have medication misunderstandings. This article will deeply analyze the emergency pharmacology mechanism, combine the latest clinical guidelines, and provide a scientific and rigorous home emergency plan.

1. Identification of the disease: the golden 4-minute judgment method

1. Typical symptoms: squeezing pain behind the sternum (the first symptom in 87% of patients)

2. Pain radiates to: left shoulder/jaw/back (accounting for 62%)

3. Associated symptoms: cold sweat (79%), dyspnea (54%)

4. Duration: 3-5 minutes (beware of myocardial infarction if it exceeds 15 minutes)

2. Nitroglycerin Usage Guidelines

1. Initial dose:

Sublingual 0.3-0.6 mg (standard tablet 0.5 mg/tablet)

Take it while sitting (to reduce the risk of postural hypotension)

Swallowing is strictly prohibited (the first-pass effect reduces the bioavailability to 8%)

2. Repeated administration:

You can add one more time every 5 minutes

Maximum dose: 3 times/15 minutes (total dose ≤ 1.8 mg)

Blood pressure monitoring: systolic blood pressure needs to be >110 mmHg (contraindicated for patients with hypotension)

3. Drug failure judgment:

No burning sensation when taking the medicine (indicating that the drug is ineffective)

Shelf life after opening: Brown bottle, store away from light ≤ 3 months

3. Collaborative emergency measures

1. Posture management:

Semi-recumbent position (head of bed raised 45°)

Avoid lying flat (increases blood return to the heart by 12-15%)

2. Environmental Control:

Room temperature 22-24℃ (reduce myocardial oxygen consumption)

Open the window to ensure oxygen concentration > 21%

3. Vital Signs Monitoring:

Measure pulse every 2 minutes (target 60-100 beats/min)

Blood oxygen saturation monitoring (maintain > 95%)

4. Identification of taboo situations

1. Absolute taboos:

Systolic blood pressure <90 mmHg

Take sildenafil within 24 hours

Right ventricular myocardial infarction (3.2%)

2. Relative taboos:

Glaucoma patients (intraocular pressure ＞21mmHg)

Severe anemia (Hb < 70 g/L)

5. Indications for emergency medical treatment

1. Taking the medicine three times is ineffective (the probability of myocardial infarction increases to 68%)

2. Pain lasts for more than 20 minutes

3. Impaired consciousness/projectile vomiting

Conclusion: The correct use of nitroglycerin is a key link in the first aid of angina pectoris, but the "3-5-15" principle must be strictly followed: identification within 3 minutes, administration at 5-minute intervals, and medical attention if ineffective within 15 minutes. It is recommended that patients check the effectiveness of the drug every 6 months and cooperate with doctors to develop individualized medication plans. Remember: first aid drugs can only buy time, and timely professional treatment is the fundamental. A "four-piece first aid kit" should be established on a daily basis: nitroglycerin, sphygmomanometer, oximeter, and medical records.

Data sources: American Heart Association (AHA), European Society of Cardiology (ESC), Chinese Journal of Cardiology