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• Cardiopulmonary resuscitation (CPR): First aid

Learn the steps to perform this lifesaving technique on adults and children.

Cardiopulmonary resuscitation (CPR) is a lifesaving technique that's useful in many emergencies in which someone's breathing or heartbeat has stopped. For example, when someone has a heart attack or nearly drowns. The American Heart Association recommends starting CPR with hard and fast chest compressions. This hands-only CPR recommendation applies to both untrained bystanders and first responders.

If you're afraid to do CPR or unsure how to perform CPR correctly, know that it's always better to try than to do nothing at all. The difference between doing something and doing nothing could be someone's life.

Here's advice from the American Heart Association:

• Untrained. If you're not trained in CPR or worried about giving rescue breaths, then provide hands-only CPR . That means uninterrupted chest compressions of 100 to 120 a minute until paramedics arrive (described in more detail below). You don't need to try rescue breathing.
• Trained and ready to go. If you're well-trained and confident in your ability, check to see if there is a pulse and breathing. If there is no pulse or breathing within 10 seconds, begin chest compressions. Start CPR with 30 chest compressions before giving two rescue breaths.
• Trained but rusty. If you've previously received CPR training but you're not confident in your abilities, then just do chest compressions at a rate of 100 to 120 a minute. Details are described below.

The above advice applies to situations in which adults, children and infants need CPR , but not newborns. Newborns are babies up to 4 weeks old.

CPR can keep oxygen-rich blood flowing to the brain and other organs until emergency medical treatment can restore a typical heart rhythm. When the heart stops, the body no longer gets oxygen-rich blood. The lack of oxygen-rich blood can cause brain damage in only a few minutes.

If you are untrained and have immediate access to a phone, call 911 or your local emergency number before beginning CPR . The dispatcher can tell you how to do the proper procedures until help arrives. To learn CPR properly, take an accredited first-aid training course, including CPR and how to use an automated external defibrillator (AED).

Before you begin

Before starting CPR , check:

• Is the environment safe for the person?
• Is the person conscious or unconscious?
• If the person appears unconscious, tap or shake their shoulder and ask loudly, "Are you OK?"
• If the person doesn't respond and you're with another person who can help, have one person call 911 or the local emergency number and get the AED , if one is available. Have the other person begin CPR .
• If you are alone and have immediate access to a telephone, call 911 or your local emergency number before beginning CPR . Get the AED if one is available.
• As soon as an AED is available, deliver one shock if instructed by the device, then begin CPR .

Remember to spell C-A-B

Chest compressions

To perform chest compressions, kneel next to the person's neck and shoulders. Place the heel of one hand over the center of the person's chest and your other hand on top of the first hand. Keep your elbows straight and position your shoulders directly above your hands. Using your upper body weight, push straight down on the chest about 2 inches (5 centimeters), but not more than 2.4 inches (6 centimeters). Push hard at a rate of 100 to 120 compressions a minute. If you haven't been trained in CPR , continue chest compressions until there are signs of movement or until emergency medical personnel take over. If you have been trained in CPR , go on to opening the airway and rescue breathing.

Open the airway

If you're trained in CPR and you've performed 30 chest compressions, open the person's airway using the head-tilt, chin-lift maneuver. Put your palm on the person's forehead and gently tilt the head back. Then with the other hand, gently lift the chin forward to open the airway.

Rescue breathing

Open the airway using the head-tilt, chin-lift maneuver. Pinch the nostrils shut for mouth-to-mouth breathing and cover the person's mouth with yours, making a seal. Give the first rescue breath, lasting one second, and watch to see if the chest rises. If it rises, give the second breath. If the chest doesn't rise, repeat the head-tilt, chin-lift maneuver first and then give the second breath. Be careful not to provide too many breaths or to breathe with too much force. After two breaths, immediately restart chest compressions to restore blood flow.

The American Heart Association uses the letters C-A-B to help people remember the order to perform the steps of CPR .

• C: compressions
• B: breathing

Compressions: Restore blood flow

Compressions means you use your hands to push down hard and fast in a specific way on the person's chest. Compressions are the most important step in CPR . Follow these steps for performing CPR compressions:

• Put the person on their back on a firm surface.
• Kneel next to the person's neck and shoulders.
• Place the lower palm of your hand over the center of the person's chest, between the nipples.
• Place your other hand on top of the first hand. Keep your elbows straight. Place your shoulders directly above your hands.
• Push straight down on the chest at least 2 inches (5 centimeters) but no more than 2.4 inches (6 centimeters). Use your entire body weight, not just your arms, when doing compressions.
• Push hard at a rate of 100 to 120 compressions a minute. The American Heart Association suggests performing compressions to the beat of the song "Stayin' Alive." Allow the chest to spring back after each push.
• If you haven't been trained in CPR , continue chest compressions until there are signs of movement or until emergency medical personnel take over. If you have been trained in CPR , go on to opening the airway and rescue breathing.

Airway: Open the airway

Breathing: breathe for the person.

Rescue breathing can be mouth-to-mouth breathing or mouth-to-nose breathing if the mouth is seriously injured or can't be opened. Current recommendations suggest performing rescue breathing using a bag-mask device with a high-efficiency particulate air (HEPA) filter.

• After opening the airway (using the head-tilt, chin-lift maneuver), pinch the nostrils shut for mouth-to-mouth breathing and cover the person's mouth with yours, making a seal.
• Prepare to give two rescue breaths. Give the first rescue breath — lasting one second — and watch to see if the chest rises.
• If the chest rises, give a second breath.
• If the chest doesn't rise, repeat the head-tilt, chin-lift maneuver and then give a second breath. Thirty chest compressions followed by two rescue breaths is considered one cycle. Be careful not to provide too many breaths or to breathe with too much force.
• Continue chest compressions to restore blood flow.
• As soon as an automated external defibrillator (AED) is available, apply it and follow the prompts. Give one shock, then continue chest compressions for two more minutes before giving a second shock. If you're not trained to use an AED , a 911 operator or another emergency medical operator may be able to give you instructions. If an AED isn't available, go to step 5 below.
• Continue CPR until there are signs of movement or emergency medical personnel take over.

To perform CPR on a child

The procedure for giving CPR to a child age 1 through puberty is essentially the same as that for an adult — follow the C-A-B steps. The American Heart Association says you should not delay CPR and offers this advice on how to perform CPR on a child:

If you are alone and didn't see the child collapse, start chest compressions for about two minutes. Then quickly call 911 or your local emergency number and get the AED if one is available.

If you're alone and you did see the child collapse, call 911 or your local emergency number first. Then get the AED , if available, and start CPR . If another person is with you, have that person call for help and get the AED while you start CPR .

• Place the child on their back on a firm surface.
• Kneel next to the child's neck and shoulders.
• Place two hands — or only one hand if the child is very small — on the lower half of the child's breastbone.
• Using the heel of one or both hands, press straight down on the chest about 2 inches (approximately 5 centimeters) but not greater than 2.4 inches (approximately 6 centimeters). Push hard and fast — 100 to 120 compressions a minute.
• If you haven't been trained in CPR , continue chest compressions until the child moves or until emergency medical personnel take over. If you have been trained in CPR , open the airway and start rescue breathing.

If you're trained in CPR and you've performed 30 chest compressions, open the child's airway using the head-tilt, chin-lift maneuver.

• Place your palm on the child's forehead and gently tilt their head back.
• With the other hand, gently lift the chin forward to open the airway.

Breathing: Breathe for the child

Follow these steps for mouth-to-mouth breathing for a child.

• After using the head-tilt, chin-lift maneuver to open the airway, pinch the child's nostrils shut. Cover the child's mouth with yours, making a seal.
• Breathe into the child's mouth for one second. Watch to see if the chest rises. If it rises, give a second breath. If the chest doesn't rise, repeat the head-tilt, chin-lift maneuver first. Then give the second breath. Be careful not to provide too many breaths or to breathe with too much force.
• After the two breaths, immediately begin the next cycle of compressions and breaths. Note: If there are two people available to do CPR on the child, change rescuers every two minutes — or sooner if the rescuer is fatigued — and give one to two breaths every 15 compressions.
• As soon as an AED is available, apply it and follow the prompts. As soon as an AED is available, apply it and follow the prompts. Use pediatric pads for children older than 4 weeks old and up to age 8. If pediatric pads aren't available, use adult pads. Give one shock, then restart CPR — starting with chest compressions — for two more minutes before giving a second shock. If you're not trained to use an AED , a 911 operator or another emergency medical operator may be able to give you directions.

Continue until the child moves or help arrives.

To perform CPR on a baby 4 weeks old or older

Cardiac arrest in babies is usually due to a lack of oxygen, such as from choking. If you know that the baby has an airway blockage, perform first aid for choking. If you don't know why the baby isn't breathing, perform CPR .

First, evaluate the situation. Touch the baby and watch for a response, such as movement. Don't shake the baby.

If there's no response, call 911 or your local emergency number, then immediately start CPR .

Follow the compressions, airway and breathing method for a baby under age 1. Do not follow this procedure for newborns, which include babies up to 4 weeks old.

If you saw the baby collapse, get the AED , if one is available, before starting CPR . If another person is available, have that person call for help immediately and get the AED while you stay with the baby and perform CPR .

• Place the baby on their back on a firm, flat surface, such as a table or floor.
• Imagine a horizontal line drawn between the baby's nipples. Place two fingers of one hand just below this line, in the center of the chest.
• Gently compress the chest about 1.5 inches, which is about 4 centimeters.
• Count aloud as you push in a fairly rapid rhythm. You should push at a rate of 100 to 120 compressions a minute, just as you would when giving an adult CPR .

After 30 compressions, gently tip the head back by lifting the chin with one hand and pushing down on the forehead with the other hand.

Breathing: Breathe for the baby

• Cover the baby's mouth and nose with your mouth.
• Prepare to give two rescue breaths. Use the strength of your cheeks to deliver gentle puffs of air, instead of deep breaths from your lungs. Gently puff a breath into the baby's mouth one time, taking one second for the breath. Watch to see if the baby's chest rises. If it does, give a second rescue breath. If the chest does not rise, repeat the head-tilt, chin-lift maneuver and then give the second breath.
• If the baby's chest still doesn't rise, continue chest compressions.
• Give two breaths after every 30 chest compressions. If two people are doing CPR , give one to two breaths after every 15 chest compressions.
• Continue CPR until you see signs of life or until medical personnel arrive.

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• Highlights of the 2020 AHA guidelines update for CPR and ECC. American Heart Association. https://cpr.heart.org/en/resuscitation-science/cpr-and-ecc-guidelines. Accessed Jan. 18, 2022.
• Pozner CN. Adult basic life support (BLS) for health care providers. https://www.uptodate.com/contents/search. Accessed Jan. 18, 2022.
• FAQ: Hands-only CPR. American Heart Association. https://cpr.heart.org/en/cpr-courses-and-kits/hands-only-cpr/hands-only-cpr-resources. Accessed Jan. 18, 2022.
• Duff JP, et al. 2019 American Heart Association focused update on Pediatric Advanced Life Support: An update to the American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation. 2019; doi:10.1161/CIR.0000000000000731.
• Atkins DL, et al. 2019 American Heart Association focused update on pediatric basic life support: An update to the American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation. 2019; doi:10.1161/CIR.0000000000000736.
• Ralson ME. Pediatric basic life support (BLS) for health care providers. https://www.uptodate.com/contents/search. Accessed Jan. 18, 2022.
• Topjian AA, et al. Part 4: Pediatric basic and advanced life support: 2020 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation. 2020; doi:10.1161/CIR.0000000000000901.
• Infant. Dorland's Medical Dictionary Online. https://www.dorlandsonline.com. Accessed March 1, 2021.
• Panchal AR, et al. Part 3: Adult basic and advanced life support: 2020 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation. 2020; doi:10.1161/CIR.0000000000000916.
• Cetta Jr F (expert opinion). Mayo Clinic. April 21, 2021.
• Automated external defibrillators: Do you need an AED?
• Marathon CPR Saves Life

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CPR: What You Need to Know

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You're playing your usual weekend pickup basketball game with friends. Without warning, one of your teammates suddenly crumples to the ground. You scream out his name, but there's no response. His face turns pale and blue, and you can't see his chest rise and fall. You listen for a heartbeat, but you can't find a pulse at all. You quickly grab your cell phone and dial 911.

Sudden cardiac arrest -- or sudden cardiopulmonary arrest as it's also known -- is the leading cause of death in the United States, killing more than 325,000 men and women every year [source: Mayo Clinic ]. Fortunately, modern medicine has come up with a number of tools to help revive those who experience sudden cardiac arrest. Many of these emergency procedures require medical training and/or complex equipment; but one -- cardiopulmonary resuscitation (CPR) -- needs no additional devices and can be performed by a layperson with only a little bit of training.

In this article, we'll explore how this first aid technique can help save lives.

PLEASE NOTE: This article is not intended to be used as a method for teaching CPR. For proper CPR training, consult your local hospital or American Red Cross chapter for available classes.

Sudden Cardiac Arrest and Other Emergencies

Cpr step-by-step.

• Hands-Only CPR

CPR vs. Defibrillation

Cpr and infectious disease.

Contrary to popular belief, sudden cardiac arrest (SCA) is not the same thing as a heart attack . SCA occurs when abnormal rhythms disrupt the electrical impulses of the heart, which cause it to abruptly stop pumping. On the other hand, a heart attack (myocardial infarction) is the final stage of heart disease, a condition that slows blood flow over time. Both medical events require immediate attention; however, the prognosis for SCA is much more grim. Only about 5 percent of people who experience sudden cardiac arrest survive, while many heart attack sufferers can expect to recover [sources: Red Cross ; American Heart Association ].

Despite the varying prognoses of these heart conditions, CPR does help play a role in survival by extending the window of time a person can be kept alive before they receive additional medical attention, such as defibrillation and emergency surgery. In addition, other sudden medical events -- such as near drowning, carbon monoxide poisoning or an electrical shock -- can lead to loss of heart or lung functioning that requires CPR.

If you witness someone collapse suddenly, or if you come across a person who appears lifeless, tap him or her on the shoulder and ask if they are OK. If they don't respond, you should immediately call for emergency responders and then try to resuscitate the unconscious per using CPR. If it's a baby that appears to be in distress, stroke the infant to see if he or she responds to touch; but never shake a baby to try to get a response.

On the next page, we'll look at the different levels of CPR.

The odds of surviving sudden cardiac arrest are low, but administering CPR immediately can double or even triple a person's chances of surviving the heart episode [source: American Heart Association].

CPR is a first-aid technique used to keep victims of sudden cardiac arrest and other emergencies alive and to prevent brain damage until more advanced medical professionals can arrive. Traditional CPR has two goals: to keep oxygen flowing in and out of the lungs and to keep oxygenated blood flowing throughout the body.

While the modern emergency room has high-tech equipment and an arsenal of drugs to help treat people who are experiencing heart and breathing emergencies, CPR is a simple technique most anyone can do with little or no equipment.

There are different types of CPR, and the one you perform on a person depends on your level of training and your access to additional lifesaving aids. The following are varying levels of CPR broken down by the Mayo Clinic:

• Untrained persons -- If you've never been taught CPR, you should perform hands-only resuscitation (we'll discuss this more in detail later), which requires applying uninterrupted chest compressions at a rate of approximately 100 compressions a minute until emergency personnel arrive.
• Trained, but rusty -- If you've been trained in CPR but are unsure of your skills, experts recommend that you use the hands-only method.
• Trained and confident -- If you've taken a CPR class and are prepared to administer resuscitation, you should perform compression CPR in coordination with rescue breathing.
• Trained with access to an automatic external defibrillator -- Deliver one shock with the AED according to the device's instructions and then begin CPR.

When it comes to CPR, comprehensive training is ideal, but even some knowledge is better than no knowledge at all. In fact, hands-only CPR is just as effective as traditional CPR in the first few minutes following an attack [source: Mayo Clinic]. In the next section, we'll go over the step-by-step basics of CPR so you can be better prepared to help others in case of emergency.

In one form or another, CPR has been in use since 1740 [source: American Heart Association].

What should you do to help a seemingly unconscious victim? As we mentioned previously, the first thing you do is determine whether or not the victim is really unconscious. Call out to them, tap them and gently shake them to try and provoke a response. However, you should never shake an infant, even if you suspect he or she is unconscious.

You also should check for signs of breathing. If a person looks slightly blue in the face or if their chest is not rising and falling, there's a good chance they've stopped breathing and will need CPR. If you perform CPR on someone who does not need it, you could actually do damage, so be certain before you begin.

If you suspect someone is unconscious and you can't rouse them, the very next thing to do is have someone call 911 so paramedics will be on their way while you are performing CPR. This is very important because, with the exception of choking, CPR doesn't address the underlying causes of cardiac arrest and other breathing emergencies. It is only meant to buy time until the victim can get intensive medical care.

After you've called for medical assistance, you should begin CPR. In order for CPR to work, the person must be lying on his or her back on a hard, flat surface. If he or she is face down, gently roll him or her toward you while, supporting the neck. Once the person is on their back, you can then use the C-A-B method, which stands for:

• Circulation -- start chest compressions
• Airway -- clear obstructed airways
• Breathing -- perform mouth-to-mouth or mouth-to-nose breathing

Step one ("circulation") is the only one you should perform if you have no training in CPR -- it's called the hands-only method and we discuss it in detail next.

Current CPR guidelines don't require a layperson to check a victim's pulse before starting CPR. Why not? Because the average person has a lot of trouble finding and accurately determining a pulse. Think about how difficult it can be to find your own pulse, and then imagine trying to repeat the process on an unresponsive person. Skipping an initial pulse check simplifies CPR and saves valuable time; every minute that you delay starting CPR reduces the odds that the victim will survive.

You probably know that mouth-to-mouth resuscitation has always been a prominent component of CPR. However, in recent years, experts have changed the process to emphasize the highest-priority method -- chest compressions -- and to make layperson-conducted CPR more effective.

The steps for performing CPR used to follow the acronym "A-B-C" -- airway, breathing and circulation. But as we discussed earlier, CPR should now be performed C-A-B -- circulation, airway and breathing. The American Heart Association introduced this new approach in 2010 as a way to make chest compressions the priority of CPR.

If you take classes to learn advanced CPR methods, you'll be trained to provide airway and breathing support to a victim. If you are untrained, however, you should focus only on the circulation step.

For this method, known as hands-only CPR, you essentially become a surrogate heart to pump oxygenated blood to the rest of the victim's body. How can you have any effect on blood flow from outside of the body? All it takes is your hands and some strength. The steps are simple and include the following:

• While kneeling near the victim's neck and shoulders, place the heel of your hands one atop the other in the center of the person's chest (midway between the nipples). Keep your elbows straight and your shoulders positioned over the same area as your hands.
• Using the weight of your upper body (rather than just your arms), push the chest down. You should try to compress his or her chest 1 to 2 inches (2.54 to 5.08 cm).
• Push hard, and aim to complete at least 100 (or more) compressions per minute. To keep the appropriate speed and pace, try the mnemonic technique of singing "Stayin' Alive" by the Bee Gees and match the chest compressions to the pace of the song. This particular disco classic has 103 beats per minutes and can stay in your head easily as you perform CPR [source: Fox News ].
• If your victim is a baby, use two fingers rather than two hands to compress the middle of the chest, and be less aggressive with your compressions -- about 1.5 inches (4 cm) deep. Still try to complete at least 100 in one a minute, just as you would with an adult [source: Mayo Clinic].

In reality, all you are doing is squeezing the heart between the breastbone and the backbone to force blood out. Compressing the chest creates positive pressure inside the chest that pushes oxygenated blood out of the heart through the aorta. From here, it travels to the brain and then on to other parts of the body, delivering oxygen for cellular respiration.

It may sound easy enough in theory, but when someone collapses in front of you, your first reactions can be confusion and terror. But while you're panicked and unable to act, valuable minutes are slipping away. To counter this, many organizations, such as the American Red Cross, offer classes that give you hands-on practice to hone your CPR skills. There are even online sites, like HandsOnlyCPR.org, that simulate the compression-only method online and help you learn the speed and rhythm at which you need to perform it.

Keep reading to learn more about the difference between CPR and defibrillation.

CPR extends the window of opportunity for professionals to perform more elaborate first aid procedures, but by itself it cannot save the majority of victims of sudden cardiac arrest. Most of the people who experience SCA have ventricular fibrillation (VF) , which causes the heart muscle to quiver rapidly and beat improperly. CPR cannot correct VF. An electrical shock, known as defibrillation , is what's required to successfully restore a normal heartbeat in someone with the condition.

The shock itself doesn't switch the heart back on -- it's not like flipping a tripped circuit breaker. Instead, defibrillation actually stops the heart briefly. This gives the pacemaking cells a chance to re-establish a normal heartbeat.

So why do CPR at all if it can't address the root causes of sudden cardiac arrest? The bottom line is that CPR is an important part of a comprehensive response to a cardiac emergency. Defibrillation requires special equipment -- an automatic external defibrillator (AED) -- that has to be brought to the patient, and CPR can keep a patient alive until it arrives. In fact, defibrillation is less successful when CPR hasn't been performed [source: American College of Emergency Physicians].

CPR is helpful for those suffering from SCA, but does it pose any hazards to the person performing it? Check out the next section to learn more.

It's clear that CPR is an effective part of the emergency response to cardiac arrest and other emergencies -- one that could potentially save thousands of lives a year. Yet, in most cases, victims aren't getting this lifesaving treatment, even when bystanders are familiar with CPR.

Why won't people perform CPR on strangers? It turns out that most people are afraid of doing it incorrectly or inadvertently harming the victim further [source: Sayre, et. al ]. Some people, however, may even fear they'll contract an infectious disease, if they perform CPR on a stranger. Even though there have been no documented cases of anyone catching a serious disease from performing CPR, the new recommendation of hands-only resuscitation offers an alternative that should help assuage any fears a person may have about the practice.

As we discussed, hands-only CPR focuses only on chest compressions. The mouth-to-mouth and mouth-to-nose components are left out. If you still have concerns about coming into contact with a bodily fluid like blood when performing CPR, you should keep a pair of latex gloves in your first aid kit.

Continue reading for more links to information on CPR and first aid.

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More Great Links

• American Heart Association: CPR Saves Lives
• Medline Plus: CPR
• Facts about CPR
• American College of Emergency Physicians. "Automatic External Defibrillators." (Sept. 19, 2011) http://www.emergencycareforyou.org/YourHealth/AboutEmergencies/Default.aspx?id=26022
• American Heart Association. "CPR Saves Lives." (Sept. 19, 2011) http://www.heart.org/HEARTORG/CPRAndECC/WhatisCPR/What-is-CPR_UCM_001120_SubHomePage.jsp
• American Heart Association. "Heart Attack Recovery FAQs." (Sept. 19, 2011) http://www.heart.org/HEARTORG/Conditions/HeartAttack/PreventionTreatmentofHeartAttack/Heart-Attack-Recovery-FAQS_UCM_303936_Article.jsp
• American Heart Association. "History of CPR." Feb. 8, 2011. (Sept. 19, 2011) http://www.heart.org/HEARTORG/CPRAndECC/WhatisCPR/CPRFactsandStats/History-of-CPR_UCM_307549_Article.jsp
• American Heart Association. "Resources and Learning." Oct. 24, 2009. (Sept. 19, 2011) http://handsonlycpr.org/resources
• American Red Cross. "AED Frequently Asked Questions." (Sept. 19, 2011) http://www.redcross.org/www-files/Documents/pdf/Preparedness/AED_FAQs.pdf
• American Red Cross. "Hands-Only CPR." (Sept. 19, 2011) http://www.redcross.org/portal/site/en/menuitem.d8aaecf214c576bf971e4cfe43181aa0/?vgnextoid=22f388a2e2ccb210VgnVCM10000089f0870aRCRD
• American Red Cross. "Hands-Only CPR for Witnessed Sudden Collapse." (Sept. 19, 2011) http://www.redcross.org/www-files/Documents/pdf/training/HandsOnlyCPRsheet.pdf
• FamilyDoctor.org "Cardiopulmonary Resuscitation (CPR)." Dec. 2010. (Sept. 19, 2011) http://familydoctor.org/online/famdocen/home/healthy/firstaid/basics/630.printerview.html
• Fox News. "Study: Bee Gees' 'Stayin' Alive' Has Perfect Beat for CPR." Oct. 17, 2008. (Sept. 19, 2011) http://www.foxnews.com/story/0,2933,439543,00.html
• Mayo Clinic. "Cardiopulmonary Resuscitation (CPR): First Aid." Nov. 12, 2010. (Sept. 19, 2011) http://www.mayoclinic.com/print/first-aid-cpr/FA00061/METHOD=print
• Mayo Clinic. "New Guidelines for Cardiopulmonary Resuscitation." Nov. 14, 2008. (Sept. 19, 2011) http://www.mayoclinic.org/medical-edge-newspaper-2008/nov-14c.html
• Mayo Clinic. "Sudden Cardiac Arrest." (Sept. 19, 2011) http://www.mayoclinic.org/sudden-cardiac-arrest/
• Medline Plus. "CPR." June 30, 2011. (Sept. 19, 2011) http://vsearch.nlm.nih.gov/vivisimo/cgi-bin/query-meta?v%3Aproject=medlineplus&query=cpr&x=0&y=0
• Sayre, Michael R.; Berg, Robert A.; Cave, Diana M.; Page, Richard L.; Potts, Jerald; and White, Roger D. "Hands-Only (Compression-Only) Cardiopulmonary Resuscitation: A Call to Action for Bystander Response to Adults Who Experience Out-of-Hospital Sudden Cardiac Arrest : A Science Advisory for the Public From the American Heart Association Emergency Cardiovascular Care Committee." Circulation, Journal of the American Heart Association. March 31, 2008. (Sept. 19, 2011) http://circ.ahajournals.org/content/117/16/2162.full.pdf
• WebMD. "Heart Attack Causes and Symptoms." Feb. 28, 2010. (Sept. 19, 2011) http://www.webmd.com/heart-disease/heart-attack-causes-treatments

Please copy/paste the following text to properly cite this HowStuffWorks.com article:

C alibrated P eer R eview ®

Web-based writing and peer review, introduction.

Calibrated Peer Review (CPR) is a web-based, instructional tool that enables frequent writing assignments in any discipline, with any class size, even in large classes with limited instructional resources. In fact, CPR can reduce the time an instructor now spends reading and assessing student writing.

CPR offers instructors the choice of creating their own writing assignments or using the existing assignments in the rapidly-expanding central assignment library. Although CPR stems from a science-based model, it has the exciting feature that it is discipline independent and level independent. CPR has been adopted in undergraduate and graduate institutions, in professional medical and business schools, and even in secondary schools.

Calibrated Peer Review 6.4 is now available

Thursday, June 13, 2019

We are pleased to announce the release of CPR 6.4 with the following enhancements:

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Spatial Variations of the Activity of 137 Cs and the Contents of Heavy Metals and Petroleum Products in the Polluted Soils of the City of Elektrostal

• DEGRADATION, REHABILITATION, AND CONSERVATION OF SOILS
• Open access
• Published: 15 June 2022
• volume  55 ,  pages 840–848 ( 2022 )

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• D. N. Lipatov 1 ,
• V. A. Varachenkov 1 ,
• D. V. Manakhov 1 ,
• M. M. Karpukhin 1 &
• S. V. Mamikhin 1  

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The levels of specific activity of 137 Cs and the contents of mobile forms (1 M ammonium acetate extraction) of heavy metals (Zn, Cu, Ni, Co, Cr, Pb) and petroleum products were studied in the upper soil horizon of urban landscapes of the city of Elektrostal under conditions of local radioactive and chemical contamination were studied. In the soils within a short radius (0–100 m) around the heavy engineering plant, the specific activity of 137 Cs and the contents of mobile forms of Pb, Cu, and Zn were increased. The lognormal distribution law of 137 Cs was found in the upper (0–10 cm) soil layer; five years after the radiation accident, the specific activity of 137 Cs varied from 6 to 4238 Bq/kg. The coefficients of variation increased with an increase in the degree of soil contamination in the following sequence: Co < Ni < petroleum products < Cr < 137 Cs < Zn < Pb < Cu ranging from 50 to 435%. Statistically significant direct correlation was found between the specific activity of 137 Cs and the contents of mobile forms of Pb, Cu, and Zn in the upper horizon of urban soils, and this fact indicated the spatial conjugacy of local spots of radioactive and polymetallic contamination in the studied area. It was shown that the specific activity of 137 Cs, as well as the content of heavy metals and petroleum products in the upper layer (0–10 cm) of the soils disturbed in the course of decontamination, earthwork and reclamation is reduced.

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Contaminants migrate and accumulate in urban ecosystems under the impact of both natural and technogenic factors. The processes of technogenic migration of 137 Cs are most pronounced in radioactively contaminated territories. It was found in urboecological studies that the intensity of sedimentation of aerosol particles containing radionuclides and heavy metals is determined by the types of the surfaces of roofs, walls, roads, lawns, and parks and by their position within the urban wind field [ 12 , 26 ]. Traffic in the cities results in significant transport of dust and associated contaminants and radionuclides [ 15 , 24 ]. During decontamination measures in the areas of Chernobyl radioactive trace, not only the decrease in the level of contamination but also the possibility of secondary radioactive contamination because of the transportation of contaminated soil particles by wind or water, or anthropogenic transfer of transferring of ground were observed [ 5 , 6 ]. Rainstorm runoff and hydrological transport of dissolved and colloidal forms of 137 Cs can result in the accumulation of this radionuclide in meso- and microdepressions, where sedimentation takes place [ 10 , 16 ]. Different spatial distribution patterns of 137 Cs in soils of particular urban landscapes were found in the city of Ozersk near the nuclear fuel cycle works [ 17 ]. Natural character of 137 Cs migration in soils of Moscow forest-parks and a decrease in its specific activity in industrial areas have been revealed [ 10 ]. Determination of the mean level and parameters of spatial variations of 137 Cs in soils is one of primary tasks of radioecological monitoring of cities, including both unpolluted (background) and contaminated territories.

Emissions and discharges from numerous sources of contamination can cause the accumulation of a wide range of toxicants in urban soils: heavy metals (HMs), oil products (OPs), polycyclic aromatic hydrocarbons (PAHs), and other chemical substances. Soil contamination by several groups of toxicants is often observed in urban landscapes [ 20 , 23 ] because of the common contamination source or close pathways of the migration of different contaminants. A comprehensive analysis of contamination of urban soils by radionuclides and heavy metals has been performed in some studies [ 21 , 25 ]. The determination of possible spatial interrelationships between radioactive and chemical contaminations in urban soils is an important problem in urban ecology.

A radiation accident took place in the Elektrostal heavy engineering works (EHEW) in April 2013: a capacious source of 137 Cs entered the smelt furnace, and emission of radioactive aerosols from the aerating duct into the urban environment took place. The activity of molten source was estimated at about 1000–7000 Ci [ 14 ]. The area of contamination in the territory of the plant reached 7500 m 2 . However, radioactive aerosols affected a much larger area around the EHEW, including Krasnaya and Pervomaiskaya streets, and reached Lenin Prospect.

Geochemical evaluation of contamination of the upper soil horizon in the city of Elektrostal was carried out in 1989–1991. This survey indicated the anomalies of concentrations of wolfram, nickel, molybdenum, chromium, and other heavy metals related to accumulation of alloying constituent and impurities of non-ferrous metals in the emissions of steelmaking works [ 19 ].

The aim of our work was to determine the levels of specific activity of 137 Cs, concentrations of mobile forms of heavy metals (Zn, Cu, Ni, Co, Cr, and Pb) and oil products in the upper soil horizons in different urban landscapes of the city of Elektrostal under the conditions of local radioactive and chemical contamination.

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Lomonosov Moscow State University, 119991, Moscow, Russia

D. N. Lipatov, V. A. Varachenkov, D. V. Manakhov, M. M. Karpukhin & S. V. Mamikhin

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Lipatov, D.N., Varachenkov, V.A., Manakhov, D.V. et al. Spatial Variations of the Activity of 137 Cs and the Contents of Heavy Metals and Petroleum Products in the Polluted Soils of the City of Elektrostal. Eurasian Soil Sc. 55 , 840–848 (2022). https://doi.org/10.1134/S1064229322060072

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Received : 21 October 2021

Revised : 22 December 2021

Accepted : 30 December 2021

Published : 15 June 2022

Issue Date : June 2022

DOI : https://doi.org/10.1134/S1064229322060072

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