VERIFIED CONTENTAuthor: lek. Łukasz Kujawa

Sudden cardiac arrest (SCA for short) is a condition in which the effective work of the heart stops. The cessation of blood circulation inevitably leads to damage to the brain and other organs from hypoxia and death. Only quick rescue actions, i.e. Cardiopulmonary resuscitation (CPR) gives you a chance for survival.

Sudden cardiac arrestis associated with high mortality. Even when normal heart function is restored, prolonged ischemia can lead to irreversible tissue damage.

The most sensitive organ to hypoxia and malnutrition is the brain. It is assumed that permanent changes in the central nervous system occur as early as 4 minutes after blood flow stops. This shows how important it is to undertake basic life support measures quickly to increase your chances of survival.

The behavior of the closest witnesses of the event is of particular importance. It is worth taking part in practical BLS training, disseminating knowledge, and striving to increase access to AED, which allows you to perform defibrillation before the arrival of specialist help.

Raise public awareness of how a few simple steps can save lives.

Causes of sudden cardiac arrest

There can be many causes of cardiac arrest. They can be divided into primary and secondary.

Root causes of SCA

Root causes include all conditions in which there is direct damage to the heart muscle. These include, first of all, acute coronary syndromes (ACS), including myocardial infarction. They are the most common primary cause of cardiac arrest.

Secondary causes of SCA

Secondary SCA occurs due to non-cardiac causes. They are potentially reversible. This means that in addition to performing CPR, it is important to take steps to correct the underlying cause. Then, the chances of the patient's survival increase.

Secondary causes include :

  • hypovolemia - i.e. reduction of circulating blood volume, e.g. as a result of post-traumatic hemorrhage
  • hypoxia - oxygen deficiency in tissuescaused by respiratory disorders
  • hypothermia - core body temperature drop below 35 degrees
  • electrolyte imbalance (e.g. severe potassium deficiency) or metabolic disorders - including too low blood glucose, i.e. hypoglycaemia
  • poisoning
  • thromboembolic complications, e.g. pulmonary embolism
  • heart tamponade
  • pneumothorax - the most dangerous type is a resilient pneumothorax, most often caused by a penetrating trauma to the chest

The above causes are listed in the emergency medicine algorithms as an easy-to-remember mnemonic abbreviation (4H and 4T - hypoxia, hypovolaemia, hypothermia, hypo / hyperercalaemia / metabolic disorders & toxins, thrombosis, tamponade, tension pneumothorax).

It is worth noting that sudden cardiac arrest in the pediatric population is usually non-cardiac. The cessation of heart rate is usually secondary to respiratory arrest. The underlying cause may be respiratory failure, e.g. caused by the presence of a foreign body in the respiratory tract.

Symptoms of sudden cardiac arrest

Sudden cardiac arrest causes:

  • loss of consciousness and lack of response to stimuli (due to cessation of cerebral blood flow)
  • no perceptible breath or so-called agonizing breath
  • no palpable pulse wave on large arteries

The finding of the above symptoms requires immediate first aid and resuscitation procedures.

Sudden cardiac arrest mechanisms

The fact that a cardiac arrest occurs does not necessarily mean that the heart always completely ceases electrical and mechanical activity. The basis of SCA that leads to death is arrhythmia. Rhythms related to cardiac arrest are divided into 2 main groups, depending on the indications for defibrillation:

  • shockable rhythms

- ventricular fibrillation (VF) - pulseless ventricular tachycardia (pVT)

  • non-defibrillation rhythms (their prognosis is worse)

- asystole - electrical activity without pulse (PEA)

Electrical defibrillation is a procedure performed during CPR to deliver a direct current electrical pulse through the heart. Defibrillator discharge is designed to "organize" the heart rhythm. During CPR, defibrillation is performed on the surface of the chest using the so-called spoons.

Rapid defibrillation within 3-5 minutes of unconsciousness increases the chances of survival by as much as50-70%. Each minute of delay reduces the probability of survival by 10-12%.

Principles of providing first aid in cardiac arrest - BLS algorithm

Everyone can witness a sudden cardiac arrest - at home, in a public place or while participating in road traffic. It should not be forgotten that the obligation to provide first aid is regulated by law.

Therefore, there is no doubt that everyone should know the basic principles of first aid in case of cardiac arrest.

It is worth getting acquainted with the BLS (basic life support) algorithm. It is a set of basic life support activities intended for people without medical education who are witnesses of the event. Quickly undertaken CPR significantly increases the chances of survival.

The basic steps for BLS in adults are:

1. ASSESSMENT AND ENSURING THE SAFETY OF THE VICTIM, THE VICTIM AND THE WITNESSES OF THE EVENT

2. EVALUATION OF CONSCIOUSNESS

Gently shake the victim by the shoulders and ask loudly: "Are you alright?"

When no response:

3. AIRWAY OPENING

Lay the injured on his back, place a hand on his forehead and gently tilt his head back; place the fingertips of the other hand under the lower jaw and gently lift it

4. BREATHING EVALUATION

Holding the above-described airway unblocking maneuver, try to check if the injured is breathing; use the principle of "see, listen and feel" - lean your cheek over the mouth area while observing the movements of the chest and listening; the evaluation should not take longer than 10 seconds

NOTE: During the first few minutes of cardiac arrest, the patient may present with so-called agonizing breathing, loud, slow, irregular sighs. If abnormal breathing occurs or there is doubt about its assessment, initiate resuscitation measures.

When the patient does not respond and does not breathe properly - call the EMERGENCY TEAM (999 or 112). If there are more than one SCA witnesses, ask someone to call for help so that CPR will not be interrupted.

The medical dispatcher receiving the notification is not only responsible for sending the ambulance. It plays an important role in recognizing cardiac arrest, instructing witnesses of the incident in terms of providing help and locating the nearest AED point.

5. START CPR - 30: 2 rule

  • start chest compressions
  • after 30 compressions give 2 mouth-to-mouth rescue breaths (if you cannot / are not trained to perform effective breathsperform exclusive chest compressions)
  • continue alternating chest compressions and 30: 2 breaths

Do not interrupt CPR until:

  • professional help will arrive
  • you will be sure that the injured shows signs of life: such as: moving around, opening the eyes, proper breathing, recovery
  • you will run out

It should be mentioned that in terms of basic life support, AED is gaining more and more importance. automatic external defibrillator.

AED is a simple and intuitive device that instructs you to perform CPR by voice commands, and can analyze the rhythm and recommend a shock using self-adhesive electrodes stuck to the victim's chest.

The use of AEDs by both trained and laypeople significantly increases the patient's chances of survival. While the fact that the number of AEDs in public places is increasing, we should strive to increase public awareness and the availability of devices.

Correct Chest Compression Technique

High-quality chest compressions are essential during CPR. Quick CPR helps keep the blood flow to the most vital organs to a minimum.

This increases the chance of restoring normal heart rhythm through effective defibrillation. The following are the basic rules for the correct squeeze technique:

  • kneel at the side of the victim
  • put the wrist in the middle of the chest (lower half of the sternum - be careful not to put pressure on the ribs, abdomen or xiphoid process)
  • put the wrist of your other hand on your hand and clasp your fingers together
  • arms must be straight at elbows and perpendicular to the chest
  • the sternum is pressed to a depth of about 5 cm with a frequency of 100-120 / min

BLS in children - differences

Due to the obvious differences in the anatomy of the child and the most often different mechanism of cardiac arrest - basic life support procedures in children are slightly different.

Basic differences in BLS algorithm in children:

  • in case of lack of breathing or abnormal breathing, start CPR with 5 rescue breaths (SCA in children occurs most often in the respiratory mechanism)
  • after 5 breaths, continue CPR in the ratio of 15 chest compressions: 2 breaths
  • If CPR is provided by a lonely rescuer, it should be continued for a periodapprox. 1 minute before he or she steps away from the injured child to call for help
  • depending on the age of the child, we can use a different technique of compressing the lower half of the sternum; in the case of infants, we use the pads of two fingers or the thumbs of both hands encircling the infant's chest; in an older child, depending on his height, we can compress the chest with one or, similarly to adults - two hands with intertwined fingers.

Category:

Cardiology