Cardiac arrest
| Cardiac arrest |
Unless associated with torsades de pointes (discussed in Torsades de pointes), cardiac arrest is generally due to ventricular tachycardia or fibrillation, asystole, or electromechanical dissociation.
Immediate management
Call for assistance.
Institute life support—that is, cardiopulmonary resuscitation (CPR).
If an electrocardiographic diagnosis of the underlying rhythm is unavailable, apply:
| | immediate defibrillation beginning at 200 joules. |
This should be on a background of ongoing CPR. Subsequent treatment is probably best based on the assumption that the underlying rhythm is ventricular tachycardia or fibrillation. When a rhythm record is available, treat according to the underlying disorder.
Ventricular tachycardia or fibrillation
For management of ventricular tachycardia or fibrillation, apply:
| | up to three further defibrillation shocks in rapid succession, using the maximal output of the defibrillator. |
If this is unsuccessful, give:
| | adrenaline 1 mg (1 mL of 1 in 1000 or 10 mL of 1 in 10 000) bolus IV, repeated at 5 minute intervals until the return of spontaneous circulation. |
If possible, institute endotracheal intubation and positive pressure ventilation with 100% oxygen.
If there is no venous access, adrenaline can be given by intratracheal administration. There are no universally agreed dosage guidelines for this route, but animal studies suggest doses two to three times the intravenous dose may be required. Evidence regarding efficacy is conflicting.
Further defibrillations at maximal output, alternating with doses of adrenaline and antiarrhythmic therapy should follow.
For antiarrhythmic therapy, give:
| 1 | amiodarone 5 mg/kg IV, as a bolus, then 10 to 15 mg/kg over 24 hours | |
| | OR | |
| 2 | lignocaine 75 to 100 mg IV, over 1 to 2 minutes, followed by an IV infusion at 4 mg/minute for a maximum of 1 hour, then 1 to 3 mg/minute. |
While it was once common practice to give sodium bicarbonate routinely during CPR, this is not always necessary. If resuscitation is prolonged beyond 10 to 15 minutes, or if acidosis is confirmed by blood-gas analysis, use:
| | sodium bicarbonate 8.4% (1 mmol/mL) 1 mmol/kg IV, over 5 to 15 minutes. |
Asystole
For management of asystole, in addition to continued CPR, give:
| | adrenaline 1 mg (1 mL of 1 in 1000 or 10 mL of 1 in 10 000) bolus IV, repeated at 5 minute intervals until the return of spontaneous circulation. |
If resuscitation is not immediately successful, institute endotracheal intubation and positive pressure ventilation with 100% oxygen, if available.
If resuscitation is prolonged or acidosis is confirmed, consider:
| | sodium bicarbonate 8.4% (1 mmol/mL) 1 mmol/kg IV, over 5 to 15 minutes | |
| | AND | |
| | atropine 0.5 to 1.5 mg IV. |
The prognosis of established asystole is almost universally poor, and a decision will usually have to be made at some point to terminate resuscitation.
Electromechanical dissociation
Treatment of electromechanical dissociation is as for asystole, except that urgent consideration should be given to possible reversible causes, such as cardiac tamponade (including left ventricular rupture), severe hypovolaemia, tension pneumothorax, pulmonary embolus, and overdosage of calcium channel blockers.
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