Cardiopulmonary resuscitation

When a patient, family member, friend, or stranger stops breathing, his/her heart stops beating, or is found unresponsive, it can be one of the scariest situations of your career. However, this is also one of the times in which your knowledge and practice as a trained healthcare provider can make the difference between life and death. Basic life support (BLS) and cardiopulmonary resuscitation (CPR) is the skill set you will use to attempt to save the life of someone who otherwise would have no chance of survival. The rapid initiation and appropriate resuscitation of a person in sudden cardiac or respiratory arrest give that person the best hope of survival.

Cardiopulmonary resuscitation

How does cardiopulmonary resuscitation work?

For all of us to remain alive, our brains must have a constant flow of basic nutrients to function. One of the most important of these basic nutrients is oxygen. Oxygen is taken in from the air we breathe, absorbed into our blood through our lungs, and pumped by our hearts into our brains. If there is any significant interruption in this constant cycle of oxygenated blood flow to the brain, we die.

The heart is, in essence, a large muscle that pumps blood to the brain and all other parts of the body. As it is a muscle, the heart also needs the nutrients found in blood so that it can have the energy to function. It gets these nutrients through the blood delivered by the coronary arteries, the arteries that run over the top of the heart and come directly off of the aorta, the central artery of the body.

Blood is able to store a certain amount of oxygen and other basic nutrients for a short amount of time. This is why we are able to hold our breath for short periods and do not have to be constantly eating food to remain alive.

In essence, CPR is attempting to re-create the function of the heart and lungs when they are not able to function on their own. This is why it is called cardiopulmonary resuscitation: cardio – (Latin/Greek: “heart”), pulmo (Latin/Greek: “lungs”) resuscitation (Latin: “the act of reawakening something/someone”). By pushing down on someone’s chest and breathing air into the lungs, you are re-creating the function of the heart and lungs in an attempt to get the blood’s nutrients to the brain.

The first step of cardiopulmonary resuscitation: identify the need

How do you know if someone needs CPR? Identifying the need to start CPR can often be one of the hardest steps. A sense of shock and disbelief, in response to an event so out of the ordinary, often overwhelms the potential caregiver. However, rapid initiation of CPR leads to improved survival (the less time the brain is without the nutrients in blood, the better) and therefore is the most important step in CPR.

“Shake and shout” is the first step to establish if a person is responsive. If a person is responsive, he or she does not need CPR. If a person does not respond to attempts to be physically awoken (shaking a shoulder, pinching the arm, or doing something that would be uncomfortable for a person but would not cause harm) and shouting loudly into the ear, then you need to call for help.

The second step of cardiopulmonary resuscitation: call for help and get an automated external defibrillator

A crucial step in starting CPR is obtaining help. If you are alone, yell for help. Call an ambulance immediately (phone 911 in the United States and Canada, 080 in Mexico, 999 in the UK, 112 in many countries in Europe), then try to find an automated external defibrillator (AED). An AED may be found in many public spaces designed for large groups of people (such as sport arenas, airports, large business offices), and is often marked by special signs ( Fig. 45.1 ). If you are alone and do not have a mobile device, yell for help. If no one responds to your yells for help, your first priority is to call for an ambulance, even if this requires you to leave the patient temporarily. If you see an AED sign and can quickly get to it on your way back, obtain the AED. Otherwise, return immediately to the patient and check for breathing and a pulse.

Fig. 45.1

A sign alerting the provider where an automated external defibrillator ( AED ) can be found.

The third step of cardiopulmonary resuscitation: check for breathing and a pulse

Check if the person is breathing. Look at the person’s chest to see if it is rising and falling with breathing. Some people also find it useful to put their hand on the person’s chest. Look at the person’s face to see if any air is coming in or out of the mouth or nose. To determine whether someone is breathing, observe if the mouth is open slightly or nostrils are expanding.

Common mistakes

Most people are able to recognize if someone is not breathing; however, distinguishing “agonal gasping” or “agonal breathing” from normal breathing can be hard. Agonal gasping is a movement that mimics breathing but does not actually get air into the lungs. It often occurs right before a person dies. Agonal gasping can take on several forms, the most common of which is gagging and irregular chest and mouth movements. Agonal gasping is not breathing and you must continue the CPR sequence.

At the same time as you are determining if the person is breathing, use no more than 10 seconds to check for a pulse. The most reliable parts on the body to find a pulse are the neck (for the carotid pulse, Fig. 45.2A ), followed by the groin (for the femoral pulse, Fig. 45.2B ), and then the wrist (for the radial pulse, Fig. 45.2C ). If the patient has no pulse, begin chest compressions. If the patient does have a pulse but is not breathing or has agonal gasping, give one breath every 5 to 6 seconds for 2 minutes (“rescue breathing,” see following text) and then recheck to see if the patient has a pulse. If there is a pulse but the person is still not breathing, or are having agonal gasping, continue rescue breathing. If there is no longer a pulse, begin chest compressions.

Fig. 45.2

(A) Finding the carotid pulse. (B) Finding the femoral pulse. (C) Finding the radial pulse.


It can often be very difficult to feel a patient’s pulse because of a multitude of factors (if the patient has a large amount of fat overlying the pulse, if the patient has a weak pulse because his or her heart is not functioning well, or if the pulse is irregular or very slow). There are several techniques you can use to feel for a pulse.

The first is to make sure that you are feeling in the correct location on the body. For the carotid pulse, begin at the midline of the neck and feel the hard tubular structure, the trachea or “windpipe.” Slide your fingers to either side of it and into the slight nook or soft spot between the trachea and neck muscle (the sternocleidomastoid). There are two carotids, one on either side of the trachea. For the femoral pulse, find the hip bone (the anterior superior iliac spine, which is the hard bony point on top of the hip, not on the side of the hip) and go halfway across the hip toward the groin as a starting point. Move your fingers every few seconds to the right and left if you do not feel a pulse. For the radial pulse, mentally divide the back side of the wrist in half. Using the half of the wrist that is on the thumb side, mentally divide this area in half again. Put your fingers along this imaginary line.

For all pulse checks, use two fingers (your index and middle finger) and the most sensitive area of your finger (this is the very tip of your finger just underneath your fingernail). If there are multiple people, have at least two people check for pulses simultaneously (carotid and femoral or carotid and radial if the patient is clothed).

If you still do not feel a pulse, if you are unsure that you are checking the correct spot, or if you think the patient has a pulse but you are unable to feel it, you must start chest compressions. If the patient really does have a pulse and you are unable to feel it, chest compressions will not stop a heart from beating. If the patient does not have a pulse, then you have taken the correct step by starting chest compressions immediately.

The fourth and most critical step of cardiopulmonary resuscitation: perform chest compressions

Of all the steps you do as part of CPR, early and correctly performed chest compressions are the most critical to saving a patient’s life. These are done as a cycle: 30 chest compressions followed by two breaths, done for 2 minutes, then 10 seconds to feel for a pulse. If there is no pulse, continue the cycle of 30 chest compressions followed by two breaths, done for 2 minutes, before checking for a pulse again. If two rescuers are available, one person should do chest compressions and the other person should perform the rescue breaths ( Fig. 45.3 ), as well as help the person doing the chest compressions to count and provide feedback when needed (“go faster,” “push deeper,” “let the chest recoil”).

Fig. 45.3

Two-rescuer cardiopulmonary resuscitation with one person performing chest compressions and the other performing rescue breathing.

How to perform chest compressions

Performing chest compressions can be exhausting. However, fast and deep chest compressions are critical to saving a patient’s life. High-quality chest compressions should have all of the following elements: between 100 and 120 compressions per minute, pushing down between 2 and 2.5 inches (5–6 cm) into the chest, letting the chest wall recoil all the way so that it comes back to its normal starting position between each chest compression, and having as few interruptions or pauses in chest compressions as possible.


Correct positioning allows for effective chest compressions, as well as preventing the rescuer from getting exhausted too early in the resuscitation. Pushing down on the middle of the chest (above the xiphoid process, where the soft abdomen meets the hard chest wall in the middle of the body), have one hand on top of the other and use the heel of your hand to push down hard in the middle of the chest ( Fig. 45.4 ). Keep your elbows just slightly bent and your back straight. Instead of using your shoulder, back, and arm muscles to push down on the chest, have the motion start near your lower back from your waist. Performing CPR by using your waist will make you feel hot and sweaty, but allows for more muscle endurance so that you can perform effective CPR longer. Have your chest leaning over the patient so you can use the weight of your chest pushing down on your arms. This will increase the strength of your chest compressions while decreasing the amount of energy your muscles are using to further increase your endurance ( Fig. 45.5 ).

Fig. 45.4

Hand positioning for effective chest compressions.

Fig. 45.5

Proper body positioning for effective chest compressions. (A) Find the correct hand position by feeling the soft belly. (B) Move up the belly until you feel the hard chest wall and xiphoid process. (C) Place the heel of your hand at this spot on the chest wall, then place your other hand on top with fingers interlaced. (D) Proper body positioning.

One of the most common mistakes in performing chest compressions is going too slowly. You should be doing at least 100 chest compressions per minute, although no faster than 120 chest compressions per minute, as long as you are performing them effectively. To avoid going too slowly, either have someone count for you or frequently ask yourself if you can go faster. To be effective, however, compressions must be between 2 and 2.5 inches deep and allow for full chest recoil.

Sometimes, especially in the case of older adult patients, chest compressions break the ribs. When doing chest compressions, broken ribs have a crunching, clicking, or popping sensation. If you feel this, continue CPR without any interruptions or pauses. Although it is not ideal to break ribs, it is better to have broken ribs and be alive than be dead without broken ribs.

If you have multiple trained people available during CPR, use them: performing CPR is exhausting. Switch out the person performing chest compressions often. Do this with minimal amounts of pauses in chest compressions by having the next person to perform get into position with arms ready. Place yourself right next to and in parallel to the person currently performing chest compressions and count down to switch so that it happens smoothly and without pauses. One provider can check the pulse while the other performs chest compressions. Well-performed chest compressions should result in one pulse per chest compression.

How it works

The concept behind chest compressions explains why appropriate compression depth and allowing for recoil are so important. By pushing down on a patient’s chest, you are creating a pressure within the chest cavity that causes the blood in the heart to go forward toward the brain. Pushing down hard enough provides the appropriate amount of pressure necessary to allow for the blood to move forward. During the temporary pause in a chest compression, the chest is able to recoil, causing a negative “sucking” pressure within the chest that allows blood to fill up the heart, as well as to flow through the coronary arteries, giving the heart much needed oxygen and nutrients.

Rescue breathing

Rescue breathing becomes more important the longer CPR continues before a patient’s heart starts beating and he or she begins breathing spontaneously. The oxygen that is stored in the blood is used up by the brain and other parts of the body and needs to be replenished.

Effective rescue breathing first requires proper positioning of the airway (the mouth, throat, and windpipe). This can be done through the head tilt–chin lift maneuver ( Fig. 45.6 ). Place one hand on the back of the head and the other hand underneath the chin. Push with both hands (down with the hand that is on the back of the head, up with the hand underneath the chin) so that the patient’s head moves upward. It will seem as if he or she is trying to look up toward the forehead. This movement, called extension, straightens out the larynx and trachea and locks down the tongue into the floor of the mouth. This way air can pass smoothly from the mouth into the lungs. Using the hand that was on the back of the head to hold the head in place in extension, breathe one full breath into the patient’s mouth over the course of 1 second (mouth-to-mouth resuscitation, Fig. 45.7 ). Breathe enough to see the patient’s chest rise. Let the air come out of the chest fully and then repeat one more full breath: a total of two rescue breaths. Then immediately return to chest compressions. When performing rescue breathing as part of CPR, it should be done in cycles of 30 chest compressions to two rescue breaths.

Fig. 45.6

(A) Airway in need of proper positioning. (B) Head tilt–chin lift for proper airway positioning.

Jun 26, 2022 | Posted by in OPHTHALMOLOGY | Comments Off on Cardiopulmonary resuscitation
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