“Bystander CPR is the most important predictor of survival from cardiac arrest,” says an article in the Canadian Medical Association Journal (CMAJ January 9, 2017).
The article is titled “Five Things to Know About Cardio-pulmonary Resuscitation.” Here is the summary.
1. Chest compressions – importance of fast pushes
Chest compressions during CPR should be fast pushes. In adult patients with out-of-hospital cardiac arrest, a large multicentric study has shown patient survival to hospital discharge was highest when compressions were between 100 and 120 per minute.
2. During the use of a defibrillator – importance of peri-shock pauses
During cardiac arrest the heart needs to be shocked with a defibrillator. To do this chest compression has to stop for a brief moment. This is called peri-shock pauses. Peri-shock pauses should be limited to improve survival. High priority is given to minimizing interruptions for chest compressions. It is recommended that total pre-shock and post-shock pauses in chest compressions be as short as possible.
Studies have shown survival is higher for those patients who received pre-shock pauses of less than 10 seconds and total peri-shock pauses of less than 20 seconds during CPR. Peri-shock pauses should be minimized during CPR by performing compressions while the defibrillator is charging.
3. Interrupted or continuous CPR strategy?
Bystander CPR is the most important predictor of survival from cardiac arrest. Any interruptions in chest compressions are associated with reduced blood flow and worse survival.
For this reason, and because ventilation (mouth to mouthing breathing) is a difficult skill to acquire for those who are not health care professionals, the guideline update recommends that members of the public provide uninterrupted continuous chest compressions.
Trained rescuers should provide 30 chest compressions that are interrupted by no more than 10 seconds to provide two ventilations (mouth to mouth breathing).
4. Role of medications during cardiac arrest
Should we use vasopressin or epinephrine during resuscitation? The aim is to improve return of spontaneous circulation and improve survival.
Vasopressin is a hormone. Its two primary functions are to retain water in the body and to constrict blood vessels to raise blood pressure.
Epinephrine, also known as adrenaline, is a hormone. It plays an important role in the fight-or-flight response of the body by increasing blood flow to muscles, output of the heart, pupil dilation, and blood sugar. As a medication it is used to treat a number of conditions, including anaphylaxis, cardiac arrest, and superficial bleeding.
The CMAJ article says vasopressin offers no advantage over epinephrine in cardiac arrest.
There is limited evidence to suggest that vasopressin and epinephrine can improve return of spontaneous circulation. Because simplicity is important during resuscitation efforts, the guideline update specifically recommends that epinephrine be administered as soon as possible following onset of cardiac arrest.
5. Maintain patient’s temperature during cardiac arrest
A target temperature should be maintained in the post-cardiac arrest period.
All adult patients who are comatose with return of spontaneous circulation following cardiac arrest should receive targeted temperature management. The guideline update recommends selecting and achieving a single target temperature between 32°C and 36°C, which should be maintained constantly for at least 24 hours.
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