Every second counts: The application of drugs in cardiac arrest is a matter of seconds. In addition to rapid response, timely and effective CRP and other measures, the application of drugs is also very critical. I will summarize for you the main application of drugs in resuscitation.
I. Vasopressure drugs
1, epinephrine: epinephrine mainly because of its alpha-adrenergic receptor agonist properties. Its adrenergic effect can increase myocardial and cerebral blood supply during cardiopulmonary resuscitation, but it is controversial whether its β-adrenergic effect is beneficial to resuscitation because it can increase myocardial oxygen consumption and reduce subendocardial blood supply.
According to the latest 2010 AHA guidelines. Ventricular fibrillation and ventricular tachycardia, cardiac arrest, and pulseless electrical activity that are not responding to electroshock are usually detected on ECG and auscultation, and epinephrine 1 mg (1:10,000 solution) should be given immediately as a static push, with 20 ml of intravenous fluid flushed after each push from a peripheral vein to ensure delivery of the drug to the heart. The dose can be repeated after 3-5 minutes and incremental dosing is not recommended.
2. Vasopressin: Antidiuretic hormone, when administered in doses much greater than its antidiuretic effect, exerts a non-adrenergic peripheral vasoconstrictor effect. The current dose is 40 U instead of the first or second epinephrine.
Anti-arrhythmic drugs
Amiodarone is a broad-spectrum antiarrhythmic drug, mainly used in the treatment of rapid ventricular arrhythmias, such as ventricular tachycardia and ventricular fibrillation. In ventricular fibrillation, if defibrillation is ineffective, amiodarone can be administered intravenously followed by defibrillation for effective defibrillation. In CPR, it is indicated for ventricular fibrillation or pulseless ventricular tachycardia that has failed to respond to defibrillation, CRP and vasoactive drug therapy.
Dosage: The first dose of 300 mg (or 5 mg/kg) is administered intravenously or intramyocardially, diluted with 20 ml of 5% glucose solution and given as a rapid push, followed by one dose of electrical defibrillation, followed by a second dose of 150 mg 10-15 minutes later if there is no recovery, which can be repeated 6-8 times if needed. A maintenance dose of 1 mg/min for the first 24 hours, followed by 0.5 mg/min for the next 18 hours, should be used for a total of no more than 2.0-2.2 g. The drug should not interfere with CPR and defibrillation.
If amiodarone is not available, lidocaine may be used instead.
Dosage: An initial dose of 1-1.5 mg/kg intravenously, followed by 0.5-0.75 mg/kg intravenously every 5-10 minutes if ventricular fibrillation/pulseless ventricular tachycardia persists, until a maximum amount of 3 mg/kg is administered.
If the patient has definite tip-twist ventricular tachycardia, magnesium can be used. The recommended dose is 1-2 g, diluted to 10 ml with 5% glucose and then slowly pushed for 5-20 minutes. But it should be noted that magnesium is not effective for irregular or polymorphic ventricular tachycardia with normal Q-T interval.
Three, bicarbonate of Na
Sodium bicarbonate is not routinely used. In patients in cardiac arrest, appropriate aerobic ventilation to restore oxygen levels, high-quality chest compressions to maintain tissue perfusion and cardiac output, and restoration of autonomic circulation as soon as possible are the main methods to restore acid-base balance.
It is recommended only in special cases where metabolic acidosis is the cause of cardiac arrest.
Dosage: The initial dose is 1 mmol/kg, followed by 0.5 mmol/kg after 10 minutes, and the dosage is calculated based on blood gas results during resuscitation.
The dosage of sodium bicarbonate (mmol) = BE × body weight (kg) × 0.25
IV. Vasoactive drugs
Dopamine is also a non-conventional drug, which can only be used as a temporary blood pressure elevator and should not be maintained. The effects on different receptors are dose dependent.
At low doses (2-5 μg/kgqmin) and low titration, it excites dopamine receptors and causes dilation of renal, mesenteric, coronary and cerebral blood vessels. It also agonizes β1 receptors in the heart to produce positive inotropic effects. At moderate doses (5-10 μg/kgqmin), it can significantly agonize β1 receptors and enhance myocardial contractility. It also agonizes α receptors and causes peripheral vasoconstriction of skin and mucous membranes.
At high doses (> 10 μg/kgqmin), the positive inotropic and vasoconstrictive effects are more pronounced. It is used for various types of shock, especially for patients with renal insufficiency, reduced cardiac output, and increased peripheral vascular resistance who have been repleted with blood volume.
Therefore, the choice must be careful, do not get the dose wrong. Dosage: Add 20 mg of dopamine to 5% glucose 250 ml and start with 20 drops/min intravenously, adjusting the drip rate as needed, up to a maximum of 0.5 mg/min.
It is important to note that atropine may cause and/or exacerbate ventricular quiescence due to the potential for vagal hypertonia. 2010 AHA Guidelines for Cardiopulmonary Resuscitation and 2011 Chinese Expert Guidelines for Cardiopulmonary Resuscitation do not recommend routine use of atropine.
Dosing procedure.
1. ventricular fibrillation/pulseless ventricular tachycardia: When ventricular fibrillation/pulseless ventricular tachycardia persists after at least 1 defibrillation and 2 minutes of CPR, give epinephrine 1 mg or vasopressin 40 U. When ventricular fibrillation/pulseless ventricular tachycardia does not respond to CPR, defibrillation, and vasoactive drugs, give amiodarone. If amiodarone is not available, lidocaine may be given.
2, pulseless electrical activity/ventricular arrest: resuscitators should immediately perform CPR for 2 minutes, then recheck the heart rhythm and observe whether there is any change in the rhythm, and if there is no change continue to circulate for the above resuscitation measures. Once the condition of applying resuscitation drugs is available, epinephrine or vasopressin should be given, and atropine is not recommended.