The Pathophysiology of Cardiopulmonary Resuscitation (CPR)
The Pathophysiology of Cardiopulmonary Resuscitation (CPR)
According to Catherine Bon, assistant clinical instructor state university of New York (2017), Cardiopulmonary Resuscitation involves the application of chest compressions and artificial ventilation to sustain circulatory flow and oxygenation during cardiac arrest. A variation of CPR known as hands or compression only CPR (COCPR) consists exclusively of chest compressions. Even though the survival rates and neurological outcomes are dismal for patients with severe cardiac arrest, timely and appropriate resuscitation including defibrillation and implementation of post cardiac arrest care improves the survival rate and neurologic outcomes.
CPR is indicated for anyone with unresponsive normal breathing. According to Wikipedia, studies have shown that immediate CPR followed by defibrillation within 3-5 minutes improves the survival rates. In countries or cities where CPR training is among the emerging trends, the survival rates are very high since the bystanders have the adequate know how of CPR and vice versa to the countries and cities where CPR has not been upheld
Increased trainings and education given to emergency medical services (EMS) professionals and the public concerning treatment of cardiac arrest, has greatly increased cardiac arrest survival tolls.
INDICATIONS AND CONTRAINDICATIONS
CPR should be performed as soon as possible to anyone who has become unconscious and is found pulseless. Assessment of cardiac electrical activity can yield a more detailed analysis of the type of cardiac arrest as well as treatment options.
Failure of effective cardiac functioning is in most cases due to spontaneous initiation of a nonperfusing arrhythmia, also known as malignant arrhythmia. Some of the common arrhythmia include asystole, pulseless bradycardia and ventricular fibrillation (VF).
CPR should be started before the rhythm is identified and should continue whereas the defibrillator is being applied and charged. In addition, CPR should be resumed after the defibrillatory shock until pulsatile is achieved.
This is supported by studies showing that preshock pauses in CPR result in lower rates of defibrillation success and patient recovery.
The American College of Surgeons, the American College of Emergency Physicians, the National Association of EMS Physicians, and the American Academy of Pediatrics have issued guidelines on the withholding or termination of resuscitation in pediatric out-of-hospital traumatic cardiopulmonary arrest. Recommendations (as given by them) include the following:
Withholding resuscitation should be considered in cases of penetrating or blunt trauma victims who will obviously not survive.
Standard resuscitation should be initiated in arrested patients who have not experienced a traumatic injury.
Victims of lighting strike or drowning with significant hypothermia should be resuscitated.
Children who showed signs of life before traumatic CPR should be taken immediately to the emergency room; CPR should be performed, the airway should be managed, and intravenous or intraosseous lines should be placed on route.
In cases in which the trauma was not witnessed, it may be assumed that a longer period of hypoxia might have occurred and limiting CPR to 30 minutes or less may be considered.
When the circumstances or timing of the traumatic event is in doubt, resuscitation can be initiated and continued until arrival at the hospital.
Terminating resuscitation in children should be included in state protocols.
The only unconditional contraindication to CPR is the do-not-resuscitate order (DNR) or other advanced directive indicating a person’s desire to not be resuscitated in the event of cardiac arrest. A relative one if a clinician justifiably feels that the intervention would be medically ineffective. In hospitals, while administering the CPR, there is no administration of anesthesia because a person in cardiac arrest is literally unconscious, thus anesthetic agents are not characteristically required for cardiopulmonary resuscitation (CPR).
IMPORTANCE OF LEARNING CPR
Statistically, about 70-80% of cardiac arrest cases happen at home or public places where a person next to you is if not always sometimes a bystander with no medical knowledge. If the bystander is able to provide CPR then the victim’s chances of survival increases rapidly. According to Singapore Heart Foundation on The Importance of CPR, once the heart stops beating and blood flow stops, a person will lose consciousness within 15 seconds. Within another 30 to 60 seconds, he will stop breathing, and irreversible damage to his brain cells will follow after several minutes of oxygen deprivation. Therefore, time is of the essence.
It is of great need to have the knowledge of CPR as a general knowledge to the public
According to the Resuscitation Council of UK, there are various equipment that are relevant in conducting of CPR, these equipment include: protective equipment, oxygen cylinder, automated external defibrillator, adhesive defibrillator, razor, stethoscope and an absorbent towel. All these items should be available immediately a patient experiences a cardiac arrest.
However, it is important to note that CPR can be done anywhere, the most important thing is, and the provider of CPR should know the basic procedures or techniques of carrying out the procedure.
Several devices have been brought on board to assist the rescuer in technique perfection. These devices include:
Mobile apps have been published as the easiest way to learn how to conduct a CPR training. These apps come with pictures and videos that assist the users know whether they are doing the right or wrong thing
These are the devices used by the rescuer in the quest for achieving the right rate. In most cases, they are available to the health providers and may be in possession by victims who have had a history with cardiac arrest. These devices have units that give timing reminders for performing compressions.
Manual assist devices
Though they have not been enough, but these mechanical devices for chest compression is more efficient than the archaic hand technique
According to the 2010 American Heart Association (AHA) guidelines CPR comprises of three steps, performed chronologically:
For lay rescuers, compression-only CPR is recommended. Healthcare providers, however, should perform all three components of CPR (chest compressions, airway, and breathing).
CPR is effectively performed by laying the patient on a hard surface delivery of CPR on soft surfaces is generally less effective.
Chest compressions is done as follows:
put the heel of your left hand and that of your right hand on top of the left one on the patient’s chest
keep your arms straight and shoulders directly over your hands (for stability and prevent hurting the patient)
push hard and fast
Allow the chest to rise completely before pushing it down.
Compress as many times as you can
You are supposed to keep on with the compression and stop only when the following happens
The patient resumes breathing
If there is an automated external defibrillator (AED) to use
A professional comes for the rescue
AED is normally used in hospitals; it has clear and precise instructions of how to use it in the hospital setting, where patients are in gurneys or beds, appropriate positioning is often achieved by lowering the bed, having the CPR provider stand on a step stool.
Hands only CPR is not advisable to be used on patients whose cardiac arrest is due to drowning. In that case, a combination of compression with rescue breathing is of essence.
According to Catherine A. Bon, (CPR 2017) she gives a step by step procedure for doing the mouth to mouth “breathing rescue” or the bag valve mask (BVM) If the patient is not breathing. To provide the BVM, the provider does the following:
Ensure a tight seal between the mask and the patients face
Squeeze the bag with one hand for approximately 1 second forcing air into the patient’s lungs.
To provide mouth to mouth, the provider does the following:
Pinch the patient’s nostrils closed to assist with an airtight seal
Put the mouth completely over the patient’s mouth
After 30 chest compression, give 2 breaths (the 30:2 cycle of CPR)
Give each breath for approximately 1 second with enough force to make the patient’s chest rise
Failure to observe chest rise indicates an inadequate mouth seal or airway occlusion
After giving the 2 breaths, resume the CPR cycle
More commonly, health care providers use a 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.
Next, the provider checks for a carotid or femoral pulse. If the patient has no pulse, chest compressions are begun.
CPR is a lifesaving process, however, the process is so vigorous and physically not conducive to the victims. Therefore it does carry a lot of risks and also future or present complications if not done “gently” but these complications however, according to Elizabeth Otto (Complications Of CPR 2017) asserts that “the risk of complication is small and should not deter the use of CPR for a victim in need”
The following are some of the complications as by Elizabeth Otto:
Rib fracture are among the common complication of CPR. Chest compressions are normally given quickly and with enough compression that provides a lot of pressure to the ribs (which are not as strong as we may think) which may result to fracture. Elderly victims or children have the highest risk of getting a fracture during the vigorous compressions.
During the compression, ribs and bones can break. When this happens, the nearby organs such as lungs and liver can be punctured.
Vomiting and aspirations
Compressions builds pressure inside the body, which can force stomach contents up the oesophagus resulting vomiting. This causes the risk of aspiration, which makes it now difficult to supply the victim with adequate air, and can damage the lung tissue.
Body fluid exposure
Providing mouth-to-mouth rescue breathing to a victim without using a mask results to not only saliva exposure but also vomit and blood, which are in most cases present during the CPR between the victim and the rescuer. This may result to the spread of communicable disease such as AIDS.
It is important to note that The American Heart Association promotes the use of barrier mask when administering rescue breathing during the CPR.
During the rescue breathing, if air is delivered too fast or forcefully for a long time, the victim can accumulate air build up in the stomach called gastric distention. It causes the stomach to swell and places pressure on the lungs. If gastric distention occurs, CPR process may become effortless due to the decrease in oxygen supply in the lungs and can also result to aspirations and vomiting
Updated CPR and ECC Guidelines. Catherine Bon’s article gives an updated CPR and ECC guidelines as issued by three main organizations, namely The American Heart Association, The international Liaison Committee on Resuscitation (ILCOR) and finally the European Resuscitation Council as discussed below.
ILCOR is a committee that comprises of representatives from renowned resuscitation bodies and organizations. It was formed in the year 1993 with the aim of providing an opportunity for the major organizations in resuscitation to work and share ideas. One of its role apart from uniting these organizations is looking at the necessary responses in the treatment of cardiac arrest cases. European Resuscitation Council (ERC) is the European interdisciplinary council for resuscitation medicine and medical care. Formed in the year 1989 responsible for giving out algorithms through their mission statement “to preserve human life by making high quality resuscitation available to all” while The American heart Association (AHA), is an American non-profit organization well known for fostering appropriate cardiac care to reduce disability and death caused by cardiovascular disease and stroke. Was formed in 1924 as “association for the prevention and relief of heart diseases” both ERC and AHA have representatives in the ILCOR.
These organizations rolled out a number of recommendations in the reviewed guidelines that touched on various areas that needed more efficiency. These areas included:
Post cardiac arrest care
Adult basic life support
Cardiac arrest in special circumstances
Principles of education in resuscitation
Education, implementation and team (EIT)
Also in the year 2015, the AHA’s revision of the CPR sequence of chest, airway and breathing from the initial airway, breathing and chest compression was confirmed. This update according to an article by Catherine Bon, Cardiopulmonary Resuscitation 2017, gave rise to new recommendations for efficiency in CPR. These recommendations included:
100-120/min rate of compressions of the chest
For an adult, compression depth should not exceed 2.4 inches
“Pre and postshock” pauses should be as short as possible to prevent complications and enhance the CPR
It also lay recommendations to the responders. Which included:
Responders if untrained, should ONLY provide the chest compression CPR, to prevent the risks associated with mouth to mouth or the rescue breathing process
Responders should continue the compressions until the assistance of a trained personnel is available
Recommendations for the dispatchers include:
The dispatchers should enquire whether the victim is unresponsive with unusual breathing. If the victim has abnormal breathing, then it can be assumed to be a cardiac arrest.
Telephone instruction on the chest compressions should be provided to the callers. This improves the performance of the bystanders thus improving the survival rates of the victim.
Emphasis to the caller should not only be on the unresponsive to normal breathing, but also the detection to pulse since cardiac arrest results to lack of detectable pulse.
Recommendations have also been made to healthcare providers and the EMS professionals regarding their approach in the CPR process. Some of the recommendations include:
Emergency response system should always be activated once a victim shows unresponsiveness to normal breathing and the pulse cannot be detected
Just like the bystanders, chest compressions should always be initiated and sufficient ventilation should be provided to the victims if the victim experiences no breathing or no felt pulse
For victims of OHCA or IHCA rapid defibrillation should be applied. However, for OHCA with a shockable rhythm the EMS system with a priority based multitier response to be applied.
While administering the CPR, if there is signs trauma suggesting spinal injury, a jaw thrust without head tilt should be used to open the airway
Chang, M. P., Lu, Y., Aramendi, E., ; Idris, A. H. (2017). Ventilation is Associated With Increased Survival During 30: 2 Cardiopulmonary Resuscitation (CPR).
Do, W. S. Y. (2015). Cardiopulmonary resuscitation (CPR).
Gillum, S. (2017). American Heart Association e-Books Platform: A Review. Journal of Electronic Resources in Medical Libraries, 14(3-4), 145-149.
Kleinman, M. E., Brennan, E. E., Goldberger, Z. D., Swor, R. A., Terry, M., Bobrow, B. J., … ; Rea, T. (2015). Part 5: Adult basic life support and cardiopulmonary resuscitation quality. Circulation, 132(18 suppl 2), S414-S435.
Soar, J., Callaway, C. W., Aibiki, M., Böttiger, B. W., Brooks, S. C., Deakin, C. D., … ; Morrison, L. J. (2015). Part 4: advanced life support: 2015 international consensus on cardiopulmonary resuscitation and emergency cardiovascular care science with treatment recommendations. Resuscitation, 95, e71-e120.