Cardiopulmonary Resuscitation (CPR): How to Perfom It in Adults?

Cardiopulmonary resuscitation (CPR) can save a life in out-of-hospital conditions. Here, you'll find out the basic aspects of it.
Cardiopulmonary Resuscitation (CPR): How to Perfom It in Adults?
Diego Pereira

Written and verified by el médico Diego Pereira.

Last update: 25 March, 2023

Cardiopulmonary resuscitation (CPR) is a simple technique that can replace and restore cardiovascular and respiratory function in patients who’ve suffered cardiorespiratory arrest. There are many reasons that can cause this condition and they usually occur in out-of-hospital settings.

The following article doesn’t intend to offer a detailed explanation of the technique, as it requires in-depth study and the completion of courses certified by certain associations. Instead, below is some brief, introductory information that can help you understand cardiopulmonary resuscitation a bit better. Keep reading!

When should CPR be done?

Cardiopulmonary resuscitation should be performed as soon as possible when an absence of pulse or breathing is detected. This is very important in the first seconds after the event that triggered the cardiorespiratory arrest, as resuscitation becomes very unlikely as time progresses.

The pulse can be measured in the femoral and carotid arteries, which are accessible and provide good information. In turn, victims of a cardiorespiratory arrest often lose consciousness very quickly, have bluish discoloration in the extremities (cyanosis, due to lack of oxygen), and pupillary dilation (mydriasis).

In many countries, it’s possible to access equipment capable of detecting the electrical activity of the heart, including in homes and common areas of cities. This includes automatic and semiautomatic defibrillators, which have easy instructions for use and which we’ll mention a little later.

What can lead to a cardiorespiratory arrest?

Despite the fact that in an out-of-hospital environment, the objective isn’t to determine the cause, knowing what the main causes of cardiorespiratory arrest are could help to identify this type of situation early. The most common causes that can be reversible by CPR are the following:

  • Hypovolemia: Due to blood loss.
  • Hypoxia: When there’s deficient oxygenation, which can occur in very severe cases of pneumonia, for example.
  • Acidosis.
  • Hypo or hyperkalemia.
  • Hypothermia: A pathological decrease in body temperature.
  • Pulmonary or coronary thrombosis: The latter is related to myocardial infarction and may be preceded by angina pectoris.
An older woman with chest pain.
A myocardial infarction is a condition that may require CPR anywhere it’s detected, whether at home or on public roads.

To understand the causes of cardiorespiratory arrest, as well as the objectives of CPR, it’s important to consider that in cardiorespiratory arrest, all circulation processes are interrupted.

The heart stops pumping, even though it has electrical activity. The identification of this activity is vital in order to conduct adequate CPR, both at the out-of-hospital and hospital level.

For its part, the respiratory system suffers due to the link with blood. Objectively, when it’s seen that a patient isn’t ventilating (their chest doesn’t expand) or does so very erratically, performing ventilatory support is necessary.

What are the types of CPR?

There are two main types of CPR: Basic and advanced. Basic CPR is intended to precariously replace cardiovascular and respiratory function, generally in out-of-hospital conditions and by non-health personnel. It’s usually done in the first moments after the cardiorespiratory arrest is detected and its final objective is to guarantee an adequate transfer to a care center.

On the other hand, advanced CPR is that which includes trained health personnel and special equipment. In addition, the use of drugs in hospital conditions is possible, which is closely related to the success of resuscitation.

In recent years, the terms basic and advanced life support have been formulated. The difference is that both incorporate training aspects related to prevention and critical care after resuscitation.

The first objective of these maneuvers is to substitute or replace cardiovascular and respiratory functions. This is accomplished through cardiac compressions or massages, which may cause the heart to pump blood, in addition to assisted ventilation.

This doesn’t mean that resuscitation is always achieved during the process, as this term can only be used when contractions and ventilation have recovered spontaneously.

How to do CPR?

Basic CPR requires knowledge of the chain of survival. In its early phases, the intention is to recognize cardiorespiratory arrest and alert other people to ensure transfer to a hospital.

Early recognition

This implies the detection of a cardiorespiratory arrest, taking into account the aspects mentioned at the beginning of the article. The absence of ventilation and pulse are indicative to start CPR immediately.

If the patient is breathing and has a pulse but isn’t conscious, they’re not in cardiac arrest. The measures should be directed toward what could have caused the loss of consciousness, such as bleeding, dehydration, and trauma, among others.

It’s important to secure the area and avoid risks for the person who’s going to initiate CPR, especially in areas of car accidents or related scenes. After this, asking for help is vital to guarantee an adequate CPR process and transfer to a care center.

Early CPR

It’s crucial to verify that the airway is open, as in many cases, the tongue can obstruct it. To do this, the neck must be hyperextended, placing one hand on the forehead and the other on the chin, while pulling backward. This should be avoided in cases of suspected whiplash.

To start compressions, the operator should stand on one side of the patient and on a rigid surface. You’ll have to place one of your hands in the precordial region and extend all the fingers. The other hand should be closed into a fist on top of the outstretched hand, interlocking all the fingers.

The number of compressions varies depending on the literature, although it’s considered acceptable to perform 30 compressions in a row or about 100 per minute. For these to be effective, they have to be constant, firm, but not too abrupt, without bending the elbows.

After the compressions, ventilations or insufflations can begin, two being necessary before proceeding to the next cycle.

Early defibrillation

Some causes of cardiorespiratory arrest, such as heart attacks, also involve abnormal electrical activity of the heart. This isn’t enough to pump blood, which is why the stop occurs. Depending on the type of pattern seen on the electrocardiogram, there are rhythms that can be shockable by electricity.

This means that they can be reversed, greatly improving the patient’s prognosis. The difference with non-shockable rhythms is that, in the absence of electrical intervention, survival decreases in a few minutes.

These rhythms are ventricular fibrillation and pulseless ventricular tachycardia. This may all sound a bit complicated, but the presence of semi-automatic defibrillators makes everything easier.

These are devices that can be easily purchased, even in public places in some cities. They’re placed on the patient and allow the identification of a shockable rhythm in cases of cardiorespiratory arrest. In positive cases, it can be activated to emit electrical activity.

Doctor reads an electrocardiogram.
The electrical activity of the heart determines the possibility of reversing the process or not with a discharge from a defibrillator.

Advanced CPR or post-resuscitation care

Resuscitation should be maintained until resuscitation is achieved, at least in out-of-hospital settings. In the event that this isn’t possible, the transfer of the patient to a hospital must be managed from the first moments of the chain of survival.

In the hospital, health professionals will be able to continue the process and use medicines or defibrillators, in the case of not having a semi-automatic device. It’s not always possible to achieve resuscitation, especially in elderly patients.

But when this is achieved, doctors must perform a series of steps post-resuscitation, which includes recognizing the cause that led to the arrest and transferring the patient to an intensive care unit (ICU).

Cardiopulmonary resuscitation saves lives

Cardiopulmonary resuscitation is a simple process that, in its basic stage, can be performed by anyone in out-of-hospital settings. A novel aspect is the incorporation of semiautomatic defibrillators in public places and homes, which could help save many lives.

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