eMedicine Specialties > Clinical Procedures > Cardiothoracic Procedures

Cardiopulmonary Resuscitation (CPR)

Benjamin S Abella, MD, MPH, Assistant Professor, Department of Emergency Medicine, Clinical Research Director, Center for Resuscitation Science, Co-Chair, Hospital Code Committee, University of Pennsylvania
Noah T Sugerman, EMT, Clinical Research Assistant, Center for Resuscitation Science, Department of Emergency Medicine, Hospital of the University of Pennsylvania; Emergency Medical Technician, Narberth Ambulance, Ardmore, Pennsylvania

Updated: Mar 29, 2009

Introduction

Cardiopulmonary resuscitation (CPR) consists of chest compressions and artificial ventilation used to maintain circulatory flow and oxygenation during cardiac arrest.

Of the more than 300,000 cardiac arrests that occur annually in the United States, survival rates are typically less than 10% for out-of-hospital events and less than 20% for in-hospital events.^{[1,2,3,4,5 ]}Additionally, studies have shown that survival falls by 10-15% for each minute of cardiac arrest without CPR delivery.^{[6,7 ]}Bystander CPR initiated within minutes of the onset of arrest has been shown to improve survival rates 2- to 3-fold.^{[8 ]}

This article focuses on CPR, which is just one aspect of resuscitation care. Other interventions, such as the administration of pharmacologic agents, cardiac defibrillation, invasive airway procedures, and various diagnostic maneuvers^{[9,10 ]}are beyond the scope of this article. For more information, visit Medscape's Resuscitation Resource Center. For specific information on the resuscitation of neonates, see eMedicine article Neonatal Resuscitation.

Indications

CPR should be performed immediately on any person who has become unconscious and is found to be pulseless. Assessment of cardiac electrical activity via rapid "rhythm strip" recording can provide a more detailed analysis of the type of cardiac arrest as well as indicate additional treatment options.

Loss of effective cardiac activity is generally due to the spontaneous initiation of a nonperfusing arrhythmia, sometimes referred to as a "malignant arrhythmia." The most common nonperfusing arrhythmias include the following:

• Ventricular fibrillation (VF)
• Pulseless ventricular tachycardia (VT)
• Pulseless electrical activity (PEA)
• Asystole
• Pulseless bradycardia

Contraindications

• The only absolute contraindication for CPR is a Do Not Resuscitate (DNR) order or other advanced directive indicating a person's desire to not be resuscitated in the event of cardiac arrest.
• A relative contraindication for performing CPR is if a clinician justifiably feels that the intervention would be medically futile, although this is clearly a complex issue that is an active area of research.^{[14,15 ]}

Anesthesia

• Because a person in cardiac arrest is almost invariably unconscious, anesthetic agents are not typically required when performing CPR.

Equipment

• CPR, in its most basic form, can be performed anywhere without the need for specialized equipment.
• Universal precautions (ie, gloves, mask, gown) should be taken. However, the vast majority of CPR in the out-of-hospital setting is delivered without such protections, and no cases of disease transmission via CPR delivery have been reported.
• Although CPR can be performed with no equipment, proper technique (see Technique) is essential.
• Some hospitals and emergency medical services (EMS) systems employ devices to provide mechanical chest compressions, although studies have not yet shown such devices to be more effective than high-quality manual compressions.^{[16 ]}
• Additionally, other health systems have begun to implement devices to monitor CPR electronically and provide audiovisual CPR feedback to providers, thereby helping them improve the quality of compressions during CPR.^{[17,18,19,20 ]}
• Artificial respirations can be provided by bystanders in the absence of equipment using mouth-to-mouth technique (see Technique for instructions).
• An Advanced Cardiac Life Support (ACLS) provider (ie, physician, nurse, paramedic) may also elect to insert an endotracheal tube directly into the trachea of the patient (intubation), which provides the most efficient and effective ventilations.
• An additional device employed in the treatment of cardiac arrest is a cardiac defibrillator. This device provides an electrical shock to the heart via 2 electrodes placed on the patient's chest and can restore the heart into a normal perfusing rhythm.

Positioning

• CPR is most easily and effectively performed by laying the patient supine on a relatively hard surface, which allows for effective compression of the sternum. Delivery of CPR on a mattress or other soft material is generally less effective.
• The health care provider giving compressions should be positioned high enough above the patient so he or she is able to gain leverage and use his or her body weight to adequately compress the chest.
  • 
    

    

    CPR positioning. Video courtesy of Daniel Herzberg, 2008.

    
    
  • In the hospital setting with patients in gurneys or beds, this is often achieved by lowering the bed, having the CPR provider stand on a step-stool, or both.
  • In the out-of-hospital setting, the patient is often positioned on the floor with the CPR provider kneeling over the patient.

Technique

• For an unconscious adult, CPR is initiated using the head-tilt chin-lift maneuver to open the airway and determine if the patient is breathing.
• Before beginning ventilations, rule out airway obstruction by looking in the patient’s mouth for a foreign body blocking the patient’s airway. CPR in the presence of an airway obstruction results in ineffective ventilation/oxygenation and may lead to worsening hypoxemia.
• Effective mouth-to-mouth ventilation is determined by observation of chest rise during each exhalation. Failure to observe chest rise indicates an inadequate mouth seal or airway occlusion. Two such exhalations should be given in sequence after 30 compressions (the 30:2 cycle of CPR). When breaths are completed, compressions are restarted.
  • If available, a barrier device (pocket mask or face shield) should be used.
  • More commonly, health care providers use a positive pressure bag-valve-mask (BVM), which forces air into the lungs when the bag is squeezed.
  • Several adjunct devices may be used with a BVM, including oropharyngeal and nasopharyngeal airways.
• If the patient is not breathing, 2 ventilations are given using the provider’s mouth or a BVM.
• Delivery of mouth-to-mouth ventilations. The rescuer has lifted the chin to ensure an open airway and has pinched the nostrils shut to assist with an airtight seal. Two breaths should be given, followed 30 compressions, as shown below.
  • 
    

    

    Delivery of mouth-to-mouth ventilations.

    
    
  • 
    

    

    CPR ventilation. Video courtesy of Daniel Herzberg, 2008.

    
    
  • The mouth-to-mouth technique is performed as follows:
    • The nostrils of the patient are pinched closed.
    • The provider puts his mouth completely over the patient’s mouth.
    • The provider gives a breath for approximately 1 second with enough force to make the patient’s chest rise.
  • The BVM or invasive airway technique is performed as follows:
    • The provider ensures a tight seal between the mask and the patient’s face.
    • The bag is squeezed with one hand for approximately 1 second, forcing at least 500 mL of air into the patient’s lungs.
• Next, the provider checks for a carotid or femoral pulse.
• If the patient has no pulse, chest compressions are begun, as shown below.
  • 
    

    

    Delivery of chest compressions. Note the overlapping hands placed on the center of the sternum, with the rescuer's arms extended. Chest compressions are to be delivered at a rate of 100 compressions per minute.

    
    
  • 
    

    

    CPR compressions. Video courtesy of Daniel Herzberg, 2008.

    
    
  • The heel of one hand is placed on the patient’s sternum and the other hand is placed on top of the first, fingers interlaced.
  • The elbows are extended and the provider leans directly over the patient.
  • The provider presses down, compressing the chest 1.5 to 2 inches.
  • The chest is released and allowed to recoil completely.
  • Keeping the hands in place, the compressions are repeated 30 times at a rate of 100 compressions per minute.
• After 30 compressions, 2 breaths are given.
• This entire process is repeated until a pulse returns or the patient is transferred to definitive care.
• Chest compressions can become quickly tiring. Another bystander should be prepared to take over if the initial rescuer becomes fatigued. 
• Care should be taken to not lean on the patient between compressions, as this prevents chest recoil and worsens blood flow.
• Of note, an intubated patient should receive continuous compressions while ventilations are given 8-10 times per minute.
• The above techniques refer specifically to CPR as prescribed by the basic cardiac life support (BCLS) guidelines. In the in-hospital setting, or when a paramedic or other advanced provider is present in the out-of-hospital setting, Advanced Cardiac Life Support (ACLS) guidelines call for a more robust treatment of cardiac arrest including drug interventions, ECG monitoring, defibrillation, and invasive airway procedures.

Pearls

• The key thing to keep in mind when doing chest compressions during CPR is to push fast and hard.
• Chest compressions can become quickly tiring. Another bystander should be prepared to take over if the initial rescuer becomes fatigued.
• Care should be taken to not lean on the patient between compressions, as this prevents chest recoil and worsens blood flow.
• A key determinant of survival is the rapid delivery of high-quality CPR (within minutes of cardiac arrest).
• Attempting to perform CPR is better than doing nothing at all, even if the provider is unsure if he or she is doing it correctly. This especially applies to many people’s aversion to providing mouth-to-mouth ventilations. If one does not feel comfortable giving ventilations, chest compressions alone are still better than doing nothing.

Complications

• Performing chest compressions may result in the fracturing of ribs or the sternum, though the incidence of such fractures is widely considered to be low.
• Artificial respiration using noninvasive ventilation methods (eg, mouth-to-mouth, BVM) can often result in gastric insufflation. This can lead to vomiting, which can further lead to airway compromise or aspiration. This problem is eliminated by inserting an invasive airway, which prevents air from entering the esophagus.
• When done properly, CPR can be quite fatiguing for the provider. If possible, in order to give consistent, high-quality CPR and prevent provider fatigue or injury, new providers should intervene every 2-3 minutes (ie, providers should swap out, giving the chest compressor a rest while another rescuer continues CPR).

American Heart Association CPR Guidelines

In 2005, the American Heart Association Emergency Cardiovascular Care Committee (ECC) released their newest set of guidelines for CPR. In these guidelines, the compression/ventilation ratio was changed from 15:2 to 30:2, reflecting a greater emphasis on compressions.

Several recent studies have looked at the quality of CPR being performed in hospitals and EMS systems and found that providers often did not perform CPR up to the standards of the ECC guidelines.^{[20,21,13,22 ]}Specifically, they found that providers were often deficient in both rate and depth of chest compressions and often provided ventilations at too high a rate. Other studies have demonstrated the impact of inadequate rate and depth on survival.^{[23 ]} 

Another active controversy in the world of CPR research is the question of whether ventilations should be given at all during bystander CPR in the out-of-hospital setting. Several studies have concluded that stopping compressions in order to give ventilations may be detrimental to the patient’s outcome.^{[24,25,26 ]}While a bystander halts compressions to give 2 breaths, blood flow also stops and leads to a quick drop in the blood pressure that had been built up during the previous set of compressions.^{[27 ]}These data will be considered for the next revision of the ECC CPR guidelines, scheduled for 2010.

Multimedia

Media file 1: Delivery of chest compressions. Note the overlapping hands placed on the center of the sternum, with the rescuer's arms extended. Chest compressions are to be delivered at a rate of 100 compressions per minute.

Media file 2: Delivery of mouth-to-mouth ventilations.

Media file 3: CPR positioning. Video courtesy of Daniel Herzberg, 2008.

Media file 4: CPR ventilation. Video courtesy of Daniel Herzberg, 2008.

Media file 5: CPR compressions. Video courtesy of Daniel Herzberg, 2008.

References

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2. Eckstein M, Stratton SJ, Chan LS. Cardiac Arrest Resuscitation Evaluation in Los Angeles: CARE-LA. Ann Emerg Med. May 2005;45(5):504-9. [Medline].

3. Dunne RB, Compton S, Zalenski RJ, et al. Outcomes from out-of-hospital cardiac arrest in Detroit. Resuscitation. Jan 2007;72(1):59-65. [Medline].

4. Nadkarni VM, Larkin GL, Peberdy MA, et al. First documented rhythm and clinical outcome from in-hospital cardiac arrest among children and adults. JAMA. Jan 4 2006;295(1):50-7. [Medline].

5. Peberdy MA, Kaye W, Ornato JP, et al. Cardiopulmonary resuscitation of adults in the hospital: a report of 14720 cardiac arrests from the National Registry of Cardiopulmonary Resuscitation. Resuscitation. Sep 2003;58(3):297-308. [Medline].

6. Valenzuela TD, Roe DJ, Cretin S, et al. Estimating effectiveness of cardiac arrest interventions: a logistic regression survival model. Circulation. Nov 18 1997;96(10):3308-13. [Medline].

7. Wik L, Hansen TB, Fylling F, et al. Delaying defibrillation to give basic cardiopulmonary resuscitation to patients with out-of-hospital ventricular fibrillation: a randomized trial. JAMA. Mar 19 2003;289(11):1389-95. [Medline].

8. Herlitz J, Svensson L, Holmberg S, et al. Efficacy of bystander CPR: intervention by lay people and by health care professionals. Resuscitation. Sep 2005;66(3):291-5. [Medline].

9. American Heart Association. Part 4: Advanced Life Support. Circulation. 2005;112:III-25-III-54. [Full Text].

10. Nolan JP, De Latorre FJ, Steen PA, et al. Advanced life support drugs: do they really work?. Curr Opin Crit Care. Jun 2002;8(3):212-8. [Medline].

11. Chan PS, Krumholz HM, Nichol G, et al. Delayed time to defibrillation after in-hospital cardiac arrest. N Engl J Med. Jan 3 2008;358(1):9-17. [Medline].

12. Edelson DP, Abella BS, Kramer-Johansen J, et al. Effects of compression depth and pre-shock pauses predict defibrillation failure during cardiac arrest. Resuscitation. Nov 2006;71(2):137-45. [Medline].

13. Wik L, Kramer-Johansen J, Myklebust H, et al. Quality of cardiopulmonary resuscitation during out-of-hospital cardiac arrest. JAMA. Jan 19 2005;293(3):299-304. [Medline].

14. Morrison LJ, Visentin LM, Kiss A, et al. Validation of a rule for termination of resuscitation in out-of-hospital cardiac arrest. N Engl J Med. Aug 3 2006;355(5):478-87. [Medline].

15. Morrison LJ, Verbeek PR, Vermeulen MJ, et al. Derivation and evaluation of a termination of resuscitation clinical prediction rule for advanced life support providers. Resuscitation. Aug 2007;74(2):266-75. [Medline].

16. [Best Evidence] Hallstrom A, Rea TD, Sayre MR, et al. Manual chest compression vs use of an automated chest compression device during resuscitation following out-of-hospital cardiac arrest: a randomized trial. JAMA. Jun 14 2006;295(22):2620-8. [Medline].

17. Abella BS, Edelson DP, Kim S, et al. CPR quality improvement during in-hospital cardiac arrest using a real-time audiovisual feedback system. Resuscitation. Apr 2007;73(1):54-61. [Medline].

18. Morley PT. Monitoring the quality of cardiopulmonary resuscitation. Curr Opin Crit Care. Jun 2007;13(3):261-7. [Medline].

19. Kramer-Johansen J, Myklebust H, Wik L, et al. Quality of out-of-hospital cardiopulmonary resuscitation with real time automated feedback: a prospective interventional study. Resuscitation. Dec 2006;71(3):283-92. [Medline].

20. Abella BS, Sandbo N, Vassilatos P, et al. Chest compression rates during cardiopulmonary resuscitation are suboptimal: a prospective study during in-hospital cardiac arrest. Circulation. Feb 1 2005;111(4):428-34. [Medline].

21. Abella BS, Alvarado JP, Myklebust H, et al. Quality of cardiopulmonary resuscitation during in-hospital cardiac arrest. JAMA. Jan 19 2005;293(3):305-10. [Medline].

22. Valenzuela TD, Kern KB, Clark LL, et al. Interruptions of chest compressions during emergency medical systems resuscitation. Circulation. Aug 30 2005;112(9):1259-65. [Medline].

23. Edelson DP, Abella BS, Kramer-Johansen J, et al. Effects of compression depth and pre-shock pauses predict defibrillation failure during cardiac arrest. Resuscitation. Nov 2006;71(2):137-45. [Medline].

24. Ewy GA. Cardiac arrest--guideline changes urgently needed. Lancet. Mar 17 2007;369(9565):882-4. [Medline].

25. Ewy GA. Continuous-chest-compression cardiopulmonary resuscitation for cardiac arrest. Circulation. Dec 18 2007;116(25):2894-6. [Medline].

26. Cardiopulmonary resuscitation by bystanders with chest compression only (SOS-KANTO): an observational study. Lancet. Mar 17 2007;369(9565):920-6. [Medline].

27. Berg RA, Sanders AB, Kern KB, et al. Adverse hemodynamic effects of interrupting chest compressions for rescue breathing during cardiopulmonary resuscitation for ventricular fibrillation cardiac arrest. Circulation. Nov 13 2001;104(20):2465-70. [Medline].

28. Caffrey S. Feasibility of public access to defibrillation. Curr Opin Crit Care. Jun 2002;8(3):195-8. [Medline].

29. [Best Evidence] Kudenchuk PJ, Cobb LA, Copass MK, et al. Transthoracic incremental monophasic versus biphasic defibrillation by emergency responders (TIMBER): a randomized comparison of monophasic with biphasic waveform ascending energy defibrillation for the resuscitation of out-of-hospital cardiac arrest due to ventricular fibrillation. Circulation. Nov 7 2006;114(19):2010-8. [Medline].

30. Ornato JP, Hankins DG. Public-access defibrillation. Prehosp Emerg Care. Oct-Dec 1999;3(4):297-302. [Medline].

Keywords

CPR, cpr, cardiopulmonary resuscitation, resuscitation, AED, automated external defibrillator, chest compression, basic life support, cardiac arrest, defibrillation, ventricular fibrillation, ventricular tachycardia, asystole, mouth-to-mouth, pulseless ventricular tachycardia, pulseless electrical activity, pulseless bradycardia, bystander CPR, chest compressions

Contributor Information and Disclosures

Author

Benjamin S Abella, MD, MPH, Assistant Professor, Department of Emergency Medicine, Clinical Research Director, Center for Resuscitation Science, Co-Chair, Hospital Code Committee, University of Pennsylvania
Benjamin S Abella, MD, MPH is a member of the following medical societies: Alpha Omega Alpha, American Heart Association, Phi Beta Kappa, Sigma Xi, and Society for Academic Emergency Medicine
Disclosure: Philips Healthcare Grant/research funds Other; Cardiac Science Corporation Grant/research funds Other; Philips Healthcare Honoraria Speaking and teaching; Alsius Corporation Honoraria Speaking and teaching; Medivance Corporation Honoraria Speaking and teaching

Coauthor(s)

Noah T Sugerman, EMT, Clinical Research Assistant, Center for Resuscitation Science, Department of Emergency Medicine, Hospital of the University of Pennsylvania; Emergency Medical Technician, Narberth Ambulance, Ardmore, Pennsylvania
Disclosure: Nothing to disclose.

Medical Editor

Andrew K Chang, MD, Associate Professor, Department of Emergency Medicine, Albert Einstein College of Medicine, Montefiore Medical Center
Andrew K Chang, MD is a member of the following medical societies: American Academy of Emergency Medicine, American Academy of Neurology, American College of Emergency Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Chief Editor

Rick Kulkarni, MD, Assistant Professor of Surgery, Section of Emergency Medicine, Yale-New Haven Hospital
Rick Kulkarni, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: WebMD Salary Employment

Special thanks to Matthew Jones for appearing in the video demonstrations.

Web Links

American Heart Association

CPR and ECC 2005 guidelines in Circulation

University of Pennsylvania Center for Resuscitation Science

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