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Cardiopulmonary resuscitation (CPR)

Author: Alexandra Juhász

Sudden cardiac arrest can happen to anyone at any time. It can affect all age groups, including healthy young and older adults.

Quick and proper treatment is crucial in a sudden cardiac arrest; if not, it will cause sudden death within a few minutes. A minute without help decreases the success of reanimation by 7–10%.

Reanimation

Reanimation (cardiopulmonary resuscitation – CPR) is an emergency procedure that combines chest compressions, often with artificial ventilation, to preserve intact brain function until further measures are taken to restore spontaneous blood circulation and breathing in a person who is in cardiac arrest.

It includes recognizing critically ill patients and the actions taken to prevent fatal heart conditions.

First, in 1960, an electrical engineer and his medical colleagues presented closed-chest cardiac massage to clinical medicine practitioners. Until then, only ventilation techniques with or without instruments were used and developed simply because the physiology of breathing and circulation and their relationship had not yet been discovered.

Scientists were aware of the fact that the cause of death was cardiac arrest, but their only hope of restoring circulation was artificial respiration.

It was discovered during thoracic and cardiac surgeries that the heart's pump function can be artificially stimulated. In case of cardiac arrest, internal or open cardiac massage has been successfully used several times during surgeries, and with the experience gained from this technique, external cardiac massage has also been successfully performed over time.

Peter Safar, a pioneer in critical care medicine and a three-time Nobel prize nominee for medicine, was known as the father of cardiopulmonary resuscitation (CPR).

There are two types of life support: advanced (ALS) and basic (BLS). BLS is the basic procedure that anyone can start, even without a device.

The main goal of BLS is to immediately recognize sudden cardiac arrest, activate the emergency response system (chain of survival), and support the patient's circulation and respiration.

Advanced Life Support (ALS), also known as Advanced Cardiac Life Support (ACLS), is a set of life-saving protocols and skills that extend beyond Basic Life Support (BLS) but are based on it. Healthcare professionals perform ALS.

The steps of the ALS and the decisions are made by a team leader, who proceeds with the course of action based on reading the patient’s ECG. The procedure involves using a manual defibrillator, airway management devices, and administering specific medication.

Cardiac arrest causes poor and ineffective tissue perfusion. Anaerobic metabolism ensues, resulting in the production of lactic acid. This creates a “gap” metabolic acidosis, and in certain tissues, irreversible cell damage occurs.

In cardiac arrest, circulating blood in the arteries drains into the veins, putting a more significant load on the right ventricle. After the pressure becomes equal in both ventricles, the interventricular septum deviates to the left, decreasing the cavity of the left ventricle.

If circulation started spontaneously in this case, the stroke volume of the left ventricle and the perfusion of the coronary arteries would be extremely low.

Continuous chest compression may be performed with or without rescue breathing. The theory is that CPR mimics the heart's pumping blood throughout the body and maintains the supply of oxygen and nutrients to essential organs such as the brain.

The external cardiac massage model suggests that chest compressions directly compress the heart between the depressed sternum and the thoracic spine.

This ejects blood into the systemic and pulmonary circulations, while backward flow during decompression is limited by the cardiac valves. Continuous chest compressions generate a small but critical amount of blood flow to the coronary arteries. Interrupting chest compression prevents blood from flowing to vital areas in the body.

The return of spontaneous circulation (ROSC) is the resumption of sustained perfusing cardiac activity associated with significant respiratory effort after cardiac arrest. (Signs of ROSC include breathing, coughing, or movement and a palpable pulse or a measurable blood pressure.)

Most common causes of cardiac arrest are ventricular fibrillation and pulseless ventricular tachycardia.

Ventricular fibrillation (rhythm strip)

Ventricular tachycardia (rhythm strip)

These are the two types of heart electrical activities that are likely to be repaired by delivering energy. If so, this is known as a shockable rhythm.

Two types of non-shockable heart rhythms exist: pulseless electrical activity (PEA) and asystole. Therefore, defibrillation is not a viable treatment for these heart rhythms.

The semi-automatic and fully automatic external defibrillator (AED) automatically analyses the patient's heart rhythm to determine if a shock is needed.

DNAR (do not attempt resuscitation) orders apply in any care facility, in or out of the hospital, within the constraints of applicable law. In the event a patient suffers a cardiopulmonary arrest when there is no DNAR order in the medical record, resuscitation must be attempted.

A DNR is a written decision not to perform CPR in case of cardiac arrest. It is made and recorded by a senior healthcare team member, such as a general practitioner or oncologist.
DNR orders are often placed late in the disease process, e.g., in cancer care in the terminal phase of the illness.
When irreversible signs of death, such as rigor mortis, dependent lividity, decapitation, decomposition, incineration, and other apparent lethal injuries, are present, CPR should not start.

The chain of survival refers to the chain of events that must occur in rapid succession to maximize the chances of survival from sudden cardiac arrest.

Chain of survival

Early recognition and
activation of the emergency
response systemEarly CPREarly defibrillationPost resuscitation careTo prevent
cardiac arrestTo buy timeTo restart
the heartTo restore quality
of life

Elements of chain of survival

Early recognition and activation of the emergency response system
Early initiated basic life support (BLS)
Early defibrillation
Post-resuscitation care (following successful reanimation)

Steps of BLS

The main goal of BLS is to provide care for patients with life-threatening conditions until advanced-level life support can be provided.

1.) SAFETY

Assess scene safety.

Look for clear and less obvious hazards to caregivers, patients, and bystanders. Continually assess the scene for danger properly before responding to an emergency, and mitigate these if possible. Focus on the evident hazards (e.g., fire, smoke, fallen power line, biohazards, chemicals; dangers that are hidden (e.g., a needle under a casualty) or hazards which may develop (e.g., a change in the weather, movement of a vehicle or a structure, a fire which is out of control). In the case of a road accident, make sure that the ignition switches of all vehicles involved are turned off.

2.) RESPONSE

Check if there is any response from the patient.

Gently shake the patient's shoulders and loudly ask, "Can you hear me?” or “Are you alright?”
Then, give some basic commands, such as “Tell me your name!” “Open your eyes!” or” Squeeze my hand!”
Check if the patient can respond to you and follow simple commands.

3.) AIRWAY

Assess the patient’s breathing.

Look, listen, and feel for any evidence of breath sounds,
and feel for air blowing against your cheek for no more than 10 seconds.

Check that the patient’s mouth and throat are clear. Remove any apparent blockages in the mouth or nose, such as vomit, blood, food, or lost teeth. Then, with your hand on the forehead and your fingertips under the point of the patient’s chin, gently tilt the victim’s head backward, lifting the chin to open the airway. Place your face and ear over the patient’s mouth while you look for the chest rising and falling.

Gasping, or agonal respiration is a sign of irregular breathing patterns and an indicator of cardiac arrest. Gasping often sounds like snoring, snorting, or labored breathing. Agonal breathing is not proper breathing.

It is essential not to mistake agonal breathing for actual breathing and to respond to cardiac arrest victims immediately. Agonal breathing can happen in patients suffering from sudden cardiac arrest when the lower brainstem gets deprived of oxygen and produces a nonvoluntary breathing reflex. Other conditions and emergencies that can cause gasping include (cerebral) situations where restricted blood flow to the brain causes the body to desperately try to intake oxygen via a nonvoluntary agonal respiration reflex.
Lay rescuers are not expected and should not check patient’s circulation, but bystanders (lay responders) should immediately call their local emergency number to initiate a response anytime they find an unresponsive victim.

4.) CALL FOR HELP!

Call the ambulance (emergency medical service – EMS).

If breathing is absent or abnormal, start CPR immediately. Ask other bystanders to help you and call EMS. If you are alone with the patient and do not have a mobile phone, call out loudly for help. If you are alone, dial the emergency number, activate the speaker, or use the hands-free option to start CPR while getting assistance from the dispatcher immediately.

When you call to report an emergency, tell the dispatcher your current location and that CPR is performed.

The dispatcher will likely ask you further questions, so it is crucial to describe the emergency briefly. While it might be challenging to do so, try to stay calm. Include the number of people injured or in trouble and what caused the emergency. Follow the dispatcher's instructions.

5.) SEND A BYSTANDER TO GO AND FETCH AN AUTOMATED EXTERNAL DEFIBRILLATOR (AED) OR A SEMI-AUTOMATIC MODEL

Proper technique for chest compressions

Place the person on their back on a firm, flat surface.
Kneel next to the person's shoulders.
Place the heel of your hand in the center of the person's breastbone.
Place the heel of your other hand on the top of the first hand and interlock your fingers.
Keep your arms straight.

Position yourself vertically above the victim's chest and press down on the sternum at least 5 cm (but not more than 6 cm).

After each compression, release all the pressure on the chest without losing contact between your hands and the sternum. Allow the chest to recoil completely; do not lean on it.

Repeat at a rate of 100–120 compressions per minute.
Each compression and release should take an equal amount of time.

Combine rescue breathing with chest compressions:

After 30 chest compressions, open the airway again, using head tilt and chin lift.
Pinch the soft part of the nose closed using the index finger and thumb.
Allow the victim's mouth to open, but maintain a chin lift.

Take a normal breath and place your lips around the victim's mouth, ensuring you have an airtight seal.
Blow steadily into the mouth whilst watching for the chest to rise, taking about 1 second as in normal breathing.
Maintaining head tilt and chin lift, take your mouth away from the victim and watch for the chest to fall as air comes out.
Take another normal breath and blow into the victim's mouth once more to achieve a total of two rescue breaths.
Do not interrupt compressions by more than 10 seconds to deliver the two breaths, even if one or both are ineffective.
Then, return your hands to the correct position on the sternum without delay and give a further 30 chest compressions.
Continue with chest compressions and rescue breaths in a ratio of 30:2.

Available evidence from randomized controlled trials suggests that compression-only CPR is superior to standard CPR, at least when performed by untrained bystanders.

WHEN AED IS AVAILABLE

Steps to use an AED:

1. Assess scene.

Switch on the AED and follow the instructions of the AED for placing the pads on the victim's bare chest. Minimize pauses in chest compressions, if possible.

The area of CPR should be dry. Also, thoroughly dry the victim’s bare chest, upper stomach, armpits, the sides of their ribcage, and neck with a towel or dry clothing.

2. Switch on the device.

3. Once the victim’s chest is completely dry, attach the AED pads to the patient’s skin and continue CPR.

4. Before pressing the shock button (for semi-automatic models) or before the device delivers a shock automatically (for fully automatic models), shout “stand clear” to make sure that no one is touching the patient’s body.

5. After 2 minutes, the AED will say, “Stop CPR, analyzing.”

The AED is now analyzing the victim to see whether a shockable rhythm is present and instructs you again to either ”Shock advised” or “No Shock advised.”

6. Follow the instructions on the AED and perform CPR until the patient responds, you cannot continue, or a health care professional arrives and takes over care or directs cessation.

Ventricular tachycardia (VT) and ventricular fibrillation (VF) are the most common causes of sudden cardiac death.

Early defibrillation is the primary determinant of the success of resuscitative attempts. The latest Adult Basic Life Support (BLS) guidelines support the inclusion of the use of the automated or semi-automated external defibrillator (AED) as part of BLS.

These devices can measure core parameters such as compression depth and rate in real-time, helping the rescuer correct the technique if necessary. AEDs use voice prompts and visual indicators to guide the rescuer through a resuscitation sequence that may include defibrillation and/or CPR.

Basic Life Support (BLS)

Kardiovaskulárny systém

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