CPR / AED Study Guide: Part 2

Using a Bag-Mask Device:

A bag-mask device (or BVM, bag-valve mask) consists of a mask attached to a reservoir bag. They are commonly used to provide positive-pressure ventilations during CPR. They can be attached to an oxygen source to provide 100% oxygenation during resuscitation. As with the face mask, it takes practice to be able to use a bag-mask device. It can also be very difficult for one person to use a bag-mask device; therefore, it is recommended that use of a bag-mask device be used only when there are two rescuers available.

The steps to using a bag-mask device are as follows:

• Position yourself at the top of the victim’s head- this allows room for the second rescuer to provide compressions.
• Place the mask of the bag-mask device on the victim’s face, using the bridge of the patient’s nose as a guide to correct positioning.
• Use the E-C clamp technique to hold the mask in the correct position while you lift the jaw to obtain an open airway. To perform the E-C clamp technique, take the index finger and thumb of your non-dominant hand and form them into a ‘C’ around the top of the mask. Your other fingers of the same hand are used to lift the jaw (the ‘E’ part of the E-C clamp technique.
• Squeeze the bag to deliver a breath- each breath should be delivered over 1 second. Watch for chest rise. If you do not observe chest rise, you do not have a tight seal. If this occurs, reposition the mask and try again. Be careful not to overinflate the lungs- each breath should result in visible and natural chest rise.
• Provide 2 ventilations after every 30 compressions. If the patient has a pulse but is not breathing, provide one breath every 5-6 seconds (10-12 breaths/minute) and check for a pulse every 2 minutes. If the victim loses their pulse, you will need to begin chest compressions.

The Jaw Thrust Maneuver

If you suspect that a victim may have a neck or spinal cord injury (i.e., the victim has fallen, been in a motor vehicle accident or suffered another mechanism of injury that could result in injury to the neck or spinal cord), you should not use the head tilt-chin lift maneuver to open the victim’s airway. This could further damage the neck or spinal cord. Instead, you should use the jaw thrust maneuver to open and maintain the victim’s airway.

To perform this maneuver:

• Place your hands on either side of the victim’s head. Rest your elbows on the surface that the victim is laying on.
• Put the fingers of both your hands under the angle of the victim’s lower jaw and lift so that the jaw slides forward.
• Use your thumb to push the lower lip away from you if the victim’s lips close.

If you come across a victim who is down and another person is available to help, send that person to activate the Emergency Response System and find an AED while you assess whether the victim needs CPR. When you have determined that the victim requires CPR, start CPR beginning with compressions. When the second person returns (without an AED in this case):

• You should continue chest compressions and count the compressions aloud each time you compress the victim’s chest.
• The second rescuer should keep the person’s airway open using the head tilt-chin lift maneuver. The second rescuer should give two rescue breaths after every 30 compressions, using a face mask or a bag-mask device.
• You and the second rescuer should switch positions/roles about every two minutes so neither one of you gets tired. If you are counting out loud, two minutes is about 5 cycles of thirty compressions and two breaths. You should change positions sooner if the person doing compressions becomes too tired to perform high-quality compressions.
• Continue switching roles as above until EMS arrives to relieve you or the victim regains consciousness.

An AED, or automated external defibrillator, is a device that has the ability to detect and treat, through electrical energy, the lethal arrhythmias known as ventricular fibrillation and ventricular tachycardia. These rhythms are a common cause of sudden cardiac arrest.

Ventricular fibrillation is a condition in which the lower chambers of the heart, the ventricles, quiver in an unorganized fashion, which renders them incapable of pumping blood to the rest of the body. Untreated, ventricular fibrillation rapidly causes cardiac arrest. Ventricular tachycardia is a rapid rhythm also originating in the ventricles. In ventricular tachycardia, the ventricles contract so quickly, albeit in a somewhat organized fashion, that inadequate blood flow is produced. Ventricular tachycardia often precedes ventricular fibrillation. Both rhythms are lethal if not treated.

An AED sends electrical energy (a ‘shock’) through the heart, which stuns the heart and allows the normal pacemaker of the heart, usually located in the right atrium, to take over and restore a normal heart rhythm.

Early defibrillation is key to survival in cardiac arrest. For each minute that defibrillation is delayed, the chance of survival is reduced by 10%. (after 10 minutes, few people are successfully resuscitated.)

Early defibrillation can increase survival rates to greater than 50%. Rescuers should immediately begin chest compressions, and use the AED as soon as it is available and ready to use.

AEDs can be found wherever crowds of people gather- swimming pools, airports, malls, sporting arenas, schools, hotels…More and more businesses are also investing in these life-saving machines. In some communities, private AED owners are registering their AEDs with ambulance dispatch, so that they can be easily located by bystanders when needed. Make it a point to learn where the AEDs in your neighborhood or town are located- you never know when you might need one!

AEDs have been designed to be extremely “user friendly”. All you need to do as a rescuer is turn on the machine (the most important step) and listen as the machine guides you through the steps to use the AED safely and effectively. Although there are many brands of AEDs on the market, they all work in a similar fashion and are designed to be used by lay rescuers.

When an AED becomes available (i.e., when you or another rescuer have retrieved it), place it at the victim’s side, closest to the rescuer who will operate it. In this way, the other rescuer can continue performing CPR until the AED is ready to analyze and deliver a shock (if needed).

There are four universal steps to using any AED. These will be highlighted in the following list of steps so they are easily recognizable.

The steps to use an AED are as follows:

1. Turn on the machine. This is the most important step- turning on the machine will enable the AED unit to guide you through the next steps. To turn on the AED, open the top of the carrying case and push the ON button. Note: some models will turn on automatically when you lift the lid of the carrying case.
2. ATTACH AED pads to the victim’s bare chest. Expose the patient’s chest. Dry it off if wet, shave excessive hair if possible. Use adult pads for victims who are 8 years of age or older. Peel off the adhesive backing. Place one pad on the upper right chest just below the collarbone. Place the other pad on the patient’s lower left ribcage, a couple of centimeters beneath the armpit. Some pads are marked- there will be a red heart on the pad that is to be placed on the victim’s left side (the heart side).
   Press pads firmly onto the patient’s chest. Then attach the connecting cables to the AED unit. Note: some cables will come preconnected.
3. Analyze the rhythm. When the AED unit instructs you to, CLEAR the victim while the machine is analyzing the victim’s heart rhythm. This means you should ensure that no one is touching the victim, including yourself. The rescuer performing chest compressions or giving breaths will need to stop at this point. Note: some AEDs will begin to analyze the victim’s rhythm independently; for others, you will need to push the ANALYZE button. Analyzing the victim’s rhythm will take up to 10 seconds, so don’t be alarmed by this.
4. Push to shock. If a shock is advised, the machine will clearly state “SHOCK ADVISED, STAND CLEAR”. You should ensure that no one is touching the victim, including yourself. You need to look around to make sure no one is touching the victim’s body while stating “CLEAR” or some similar message that warns others a shock is to be delivered. Once you are certain that no one is touching the victim, push the SHOCK button. You will notice that the victim’s muscles contract strongly.

• If a shock is not necessary (the rhythm is not ventricular fibrillation or pulseless ventricular tachycardia), the AED will state NO SHOCK ADVISED and tell you to resume CPR
• After approximately 5 cycles of compressions and ventilations, or 2 minutes of CPR, the AED will instruct you to repeat steps 3 and 4- analyze the rhythm and push to shock if the rhythm requires a shock and the AED instructs you to do so.
• Continue CPR alternating with analysis of the rhythm until help arrives (i.e. EMS).

There are times when using an AED may present special challenges. Here’s what to do when faced with one of the following:

• The victim has a hairy chest- ideally, you should use a razor to shave the areas that will be covered by the AED pads. If a razor is not available and the AED machine is prompting you to CHECK PADS or CHECK ELECTRODES, try pressing down firmly on the AED pads to ensure good contact with the skin. If the machine continues to prompt you, quickly pull off the pads- this should remove enough hair to allow a new set of pads to adhere firmly to the victim’s skin. Many AED machines are coming equipped with a razor in the carrying case to combat this problem. If you happen to own an AED, ensure that a razor is included in the case.
• The victim is in water- if the victim is in water, pull the victim to a dry area. You are not in danger of getting a shock if the victim is in water. Water is a great conductor of electricity, so if the victim is in water, the shock will be dispersed across the skin of the victim, and the victim will not receive the full dose of electrical energy required to convert them to a normal rhythm. If the victim’s chest is wet, quickly dry the chest with a towel or your sleeve; however, the chest does NOT need to be completely dry. If the victim is lying in a small puddle or in snow, you can safely use the AED without moving the victim.
• The victim has an implanted pacemaker or defibrillator- obviously, if the victim has one of these devices, it must have failed! You will recognize these devices as a small lump under the skin on the chest, usually the upper chest on either side. Some older models may be implanted in the abdomen. They are generally about the size of a deck of cards or smaller. You will also be able to see a scar over the area. If the victim has one of these devices, avoid placing the AED pad directly over it; doing so may block delivery of the shock.
• The victim has a medication patch on their chest- many medications can now be delivered transdermally (through the skin). These includes pain medications, hormones, smoking cessation drugs, nitroglycerin and others. Do not place an AED pad over one of these patches. If it won’t delay delivery of a shock, remove the patch and wipe the skin before applying the AED pad. These patches may cause the skin to burn under the AED pad if left in place, or they may block delivery of the shock.

Now you know what to do should you encounter one of these special circumstances.

We’ve learned a lot so far! Thus far, we’ve learned how to perform compressions, maintain the airway and use an AED on an adult victim. Now it’s time to put it all together. The following steps outline how to perform CPR with an AED when there are two rescuers present.

When you come across a victim who is down and there are two rescuers present:

• Rescuer 1 checks for response and breathing- tap the victim on the shoulder and ask if they are okay. At the same time, observe the victim’s chest for breathing. If the victim is not breathing, or is breathing abnormally or only gasping, stay with the patient and prepare to perform the next steps.
• Rescuer 2 activates the emergency response system and leaves to retrieve an AED.
• Rescuer 1 checks for a carotid pulse for 5 to not more than 10 seconds. If a pulse is not felt, or the rescuer is not sure if there is a pulse, the rescuer will expose the chest (in preparation for AED use) and begin CPR, starting with chest compressions. Rescuer 1 will continue cycles of chest compressions and ventilations with a pocket mask or bag-mask device until Rescuer 2 returns with an AED.
• Rescuer 2 arrives with an AED and places it on the side opposite to Rescuer 1, who is performing chest compressions. Rescuer 2 powers on the AED and attaches the pads to the victim’s chest, also attaching the cables to the AED unit if necessary. Rescuer 1 should continue CPR while the pads are being placed, right up until it is time to analyze the victim’s heart rhythm.
• Rescuer 2 CLEARS the victim, ensuring neither rescuer is touching the victim, and waits for the AED to ANALYZE, or pushes the ANALYZE button when prompted by the AED to do so.
• Rescuer 2 pushes the SHOCK button if a shock is indicated, making sure that the victim is CLEAR beforehand.
• If no shock is needed, or after the victim has been shocked, Rescuer 2 should resume chest compressions (as Rescuer 1 may be fatigued by this time) while Rescuer 1 manages the victim’s airway and delivers breaths using the face mask or bag-mask device.
• After approximately 5 cycles of CPR, or 2 minutes, the AED will state that the victim’s rhythm should be ANALYZED. During analysis, which can take up to 10 seconds, Rescuer 2 and Rescuer 1 should switch positions, so that Rescuer 1 CLEARS the victim, pushes SHOCK if a shock is advised, and immediately resumes chest compressions (or performs chest compressions if no shock is advised). Rescuer 2 then takes over management of airway and breathing. Rescuers should switch positions every 2 minutes when it is time to ANALYZE the victim’s heart rhythm. This will prevent rescuer fatigue and ensure that rescuers are able to provide high-quality chest compressions at the proper rate and depth. CPR and analysis with the AED should continue until EMS arrives.

When there is no advanced airway in place, rescuers must pause compressions to deliver breaths using a face mask or bag-mask device. Once an advanced airway is in place, there is no longer a need to pause compressions to deliver breaths.

Why is this? If the chest is compressed during ventilations, most of the air (and thus oxygen) delivered would be forced out of the victim’s mouth before it could enter the lungs. An advanced airway means that air is reliably delivered to the lungs, regardless of whether a rescuer is applying force to the chest at the same time a breath is being delivered.

Advanced airways include:

• Laryngeal mask airways (LMAs)
• Supraglottic airway (Combitube or King LT)
• Endotracheal (ET) tube

When an advanced airway is in place, compressions are delivered at a rate of 100-120 compressions per minute. Breaths are delivered over 1 second simultaneously at a rate of 1 breath every 6 seconds (10-12 breaths per minute).

Although it is necessary to use a pocket mask or bag-mask device to deliver breaths in the healthcare setting, there are times when these devices may not be available. Should a cardiac arrest occur at home, you would likely not hesitate to perform mouth-to-mouth breathing for a relative or loved one; you might choose to give mouth-to-mouth to a friend as well. In cases such as these, you will likely decide the benefit outweighs the risk to your own health.

To provide mouth-to-mouth breaths to an adult (or child aged 1 to 8 years):

• Use the head tilt-chin lift to hold the victim’s airway open.
• Using the hand on the victim’s forehead that is maintaining the head tilt-chin lift, pinch the victim’s nose closed using the thumb and index finger.
• Inhale a regular breath, then cover the victim’s mouth with your own, creating a tight seal.
• Give one breath over 1 second, watching to see if the chest rises.
• If the chest doesn’t rise as you give the breath, repeat the head tilt-chin lift.
• Give a second breath over 1 second and watch for chest rise.
• If the second breath fails to go in, go immediately to chest compressions.

You may wonder how mouth-to-mouth breathing can sustain the victim. In actual fact, your expired air contains about 17% oxygen- this is just enough oxygen to meet the victim’s needs.

When providing mouth-to-mouth breathing, it is important not to provide breaths that are too forceful or too rapid. Doing so may cause air to enter the stomach rather than the lungs, which can cause gastric inflation. Gastric inflation may result in vomiting, and an unconscious victim may develop pneumonia if vomitus makes its way to the lungs. To avoid gastric inflation, give each breath slowly over 1 second and deliver just enough air to make the chest rise.

Respiratory arrest is defined as the cessation of breathing. During respiratory arrest, as well as inadequate breathing, the victim will still have some amount of cardiac output, which you will be able to detect as a palpable pulse.

It is important to be able to recognize respiratory arrest, or impending respiratory arrest, which may be seen as slow, irregular or gasping respirations. These abnormal respirations are inadequate to support life. Respiratory arrest inevitably leads to cardiac arrest if not treated, therefore healthcare providers should intervene quickly to prevent this deterioration by providing rescue breathing.

To provide rescue breathing when the victim has a pulse, give 1 breath every 5 to 6 seconds.

Choking in the Conscious Adult or Child (older than 1 year of age)

• Stand (Or Kneel) Behind The Victim And Wrap Your Arms Around The Victim’s Waist.
• Put One Foot In Between The Victim’s Feet And One Foot Behind You-This Position Provides Stability Should The Victim Become Unconscious And You Need To Ease The Victim To The Ground.
• Place Your Fist With The Thumb Side In Just Above The Victim’s Bellybutton And Well Below The Sternum (Breastbone).
• Grab Your Fist With Your Other Hand.
• Administer Abdominal Thrusts, Pulling Inward And Upward Until The Foreign Object Comes Out Or The Patient Becomes Unconscious. Each Thrust Should Be Forceful, Distinct And Separate.

Note: For Pregnant Or Obese Patients, Give Chest Thrusts Instead Of Abdominal Thrusts.

Choking in the Unconscious Adult or Child

• If You Are Carinig For Someone Who Is Choking And They Lose Consciousness, Lower The Victim Gently To The Ground.
• Activate Ems/Call 9-1-1
• Begin Cpr, Starting With Chest Compressions- Do Not Check For A Pulse.
• Each Time You Open The Airway To Provide Ventilations, Open The Victim’s Mouth And Check For The Object. If You Can See The Object, Turn The Victim’s Head To The Side And Sweep It Out Of The Victim’s Mouth With Your Index Finger. Never Perform A Blind Finger Sweep– This May Force The Object Farther Down The Victim’s Airway.
• If You Do Not See The Object, Attempt To Provide Breaths. If Breaths Will Not Go In, Resume Chest Compressions.
• After Approximately 5 Cycles Of Compressions And (Attempted) Ventilations, Activate Ems/Call 9-1-1 If Not Already Done.
• If The Obstruction Is Relieved, Check Responsiveness, Breathing And Pulse. Provide Rescue Breathing Or Cpr As Required. If The Victim Is Responsive, They Should Be Taken To Hospital To Rule Out Any Injury Caused By Abdominal Or Chest Thrusts.

It is generally not recommended that a rescuer move a victim unless there is a direct danger to the victim’s (or rescuer’s) life, or if it is necessary to provide care. Try to immobilize the spine and protect the head, neck, and back if it is necessary to move a victim.

The Team Approach

In many situations, there may be only one rescuer who will carry out the normal sequence of assessments and actions. However, in many situations, there is often more than one rescuer trained and willing to help.

This is when a team approach can be used. The first rescuer should take the role of team leader and delegate tasks. One rescuer can provide compressions, one can prepare to give breaths with a bag-valve mask, and one can prepare the AED. By working together, the most efficient care can be given to the patient.

Chest Compressions for Adults

Chest compressions are the most important component of CPR. Chest compressions are an attempt to mimic the normal activity of the heart. When a rescuer presses down on a victim’s chest, blood is forced out of the heart and into the arteries. When pressure on the chest is released, blood is allowed to return to the heart. A small amount of oxygen will be present in the bloodstream for several minutes after the heart ceases to beat, just enough to keep the brain alive. Compressions can keep vital organs functioning until higher level care is available.

Adult Chest Compressions

To perform compressions on an adult, place the heel of your non-dominant hand on the victim’s chest between the nipples. Then place your other hand on top of the first and interlace your fingers. The heel of your hand should be pressing on the bottom two-thirds of the sternum, avoiding the xiphoid process (the small bony prominence at the very bottom of the sternum (breastbone). You should be as close to the victim’s side as possible, with your knees against the victim’s side (this will help prevent back injury). Lock your elbows and press down hard, depressing the sternum at least 2 inches (5 cm), but no more than 2.4 inches (6 cm). Your shoulders should be positioned directly over your hands in a straight line. Push hard and fast 100 to 120 times per minute, counting out loud as you do so. It’s important that you allow the chest to recoil (return to it’s normal, relaxed position) in between compressions. If you do not allow the chest to recoil, the heart will not fill completely, which means that less blood (and therefore oxygen) will be pumped out of the heart to vital organs with the next compression.

Performing compressions is exhausting. Most people find that they become very tired after providing compressions for 2 or 3 minutes. When a person performing compressions becomes fatigued, there is a tendency to compress less firmly and more slowly; for this reason, it is recommended that rescuers trade off doing compressions every 2 minutes to prevent fatigue and optimize the quality of compressions. If you are alone, you will have to do the best you can- keep performing compressions until help arrives or you are physically so exhausted that you cannot continue.

An unconscious victim who is breathing and has a pulse should be assisted into the recovery position to protect the airway.

This position keeps the airway open, prevents aspiration of fluids into the lungs and allows fluid (such as saliva or blood that could occlude the airway) to drain from the mouth.

• Extend the victim’s arm that is closest to you above the victim’s head.
• Place the victim’s leg that is farthest away from you over his other leg.
• Place the victim’s arm that is farthest from you across his chest.
• Supporting the head and neck, roll the victim towards you.
• Position his or her top leg so the knee props up the victim’s body
• Place the victim’s hand or arm under his/ her chin to aid in keeping the airway open.

Congratulations! You’ve reached the end of the course. All that’s left to do is pass the multiple choice examination. You can access the link to the practise exam and final exam at the bottom of this page https://www.nationalcprassociation.com/courses/cpraed-certification or by going to My Account.