Management of Cardiac Arrest

Aparna Budhakar

The international guidelines for managing cardiopulmonary arrest were produced by the International Liaison Committee on Resuscitation (ILCOR) in the year 2000. The 2005 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendation (CoSTR) contains new guidelines presented by ILCOR. These changes are made to simplify resuscitation training and improve effectiveness.

This article reviews these guidelines
Cardiovascular disease is the leading cause of death all over world and sudden cardiac arrest is the major complication of cardiovascular disease.

Cardiac arrest is the cessation of cardiac mechanical activity. It is a clinical diagnosis, confirmed by unresponsiveness, absence of detectable pulse, and apnoea (or agonal respiration). Management of cardiac arrest needs good understanding of Emergency Cardiovascular Care (ECC). The two components of ECC are Basic Life Support (BLS) and Advanced Cardiac Life Support (ACLS).

Basic life support (BLS)- is the phase of ECC that includes recognition of cardiac arrest, access to the EMS system, and basic cardiopulmonary resuscitation (CPR).

Advanced cardiovascular support (ACLS)- is the phase of ECC that includes attempts to restore spontaneous circulation with basic CPR plus advanced airway management, tracheal intubation, defibrillation, and intravenous medications.

Cardiopulmonary resuscitation (CPR)- CPR is an attempt to restore spontaneous circulation through any of a broad range of manoeuvres and techniques.

Basic Life Support
Basic Life Support establishes a clear airway followed by assisted ventilation and support of the circulation, all without the aid of specialized equipment.

The steps of BLS consist of a series of sequential assessments and actions. The intent of the algorithm is to present the steps in a logical and concise manner that will be easy to learn, remember, and perform.

Before approaching the victim, the rescuer must ensure that the scene is safe. Rescuers should move trauma victims only if absolutely necessary (e.g., the victim is in a dangerous location, such as a burning building).

1) Check for Response (Fig. 1)
Once the rescuer has ensured that the scene is safe, the rescuer should check for response. To check for response, tap the victim on the shoulder and ask, “Are you all right”?

2) Activate the EMS System (Fig. 1)
If a lone rescuer finds an unresponsive adult (i.e., no movement or response to stimulation), the rescuer should activate the Emergency medical services (EMS), get an automated external defibrillator (AED) (if available), and return to the victim to provide CPR and defibrillation if needed. When 2 or more rescuers are present, one rescuer should begin the steps of CPR while a second rescuer activates the EMS system and gets the AED (Fig. 1).

3) Open the Airway and Check Breathing (Fig. 2)
To prepare for CPR, place the victim on a hard surface in a face up (supine) position. If an unresponsive victim is face down (prone), roll the victim to a supine (face up) position. A rescuer should use the head tilt-chin lift manoeuvre to open the airway of a victim without evidence of head or neck trauma. If rescuer suspects a cervical spine injury, open the airway using a jaw thrust without head extension. Because maintaining a patent airway and providing adequate ventilation is a priority in CPR, use a head tilt-chin lift manoeuvre if the jaw thrust does not open the airway (Fig. 2).

Check Breathing
While maintaining an open airway, look, listen, and feel for breathing. If rescuer do not detect adequate breathing within 10 seconds, give 2 breaths. Treat the victim who has occasional gasps as if he or she is not breathing and give rescue breaths.

4) Give Rescue Breaths
Give 2 rescue breaths, each over 1 second, with enough volume to produce visible chest rise. During CPR, blood flow to the lungs is much less than normal, so the victim needs less ventilation than normal. Also limiting the time to deliver rescue breath will reduce interruption in chest compression. Purpose of ventilation is to maintain adequate oxygenation. Avoid rapid or forceful breaths. Rescue breaths given during CPR increase pressure in the chest. This pressure reduces the amount of blood that refills the heart and in turn reduces the blood flow generated by the next group of chest compression. Therefore hyperventilation is not necessary and may be harmful because it can actually reduce the blood flow generated by chest compressions. In addition delivery of large and forceful breaths may cause gastric inflation and its complications.

Mouth-to-mouth Rescue Breathing (Fig. 3)
To provide mouth-to-mouth rescue breaths, open the victim’s airway, pinch the victim’s nose, and create an airtight mouth-to-mouth seal. Give 1 breath over 1 second, take a “regular” (not a deep) breath, and give a second rescue breath over 1 second. Taking a regular rather than a deep breath prevents rescuer from getting dizzy or lightheaded.

Mouth-to-Barrier Device Breathing
Barrier devices are available in 2 types: face shields and face masks. Face shields are clear plastic or silicone sheets that reduce direct contact between the victim and rescuer but do not prevent contamination of the rescuer’s side of the shield. Masks used for mouth-to-mask breathing contains a 1-way valve that directs the rescuer’s breath into the patient while diverting the patient’s exhaled air away from the rescuer.

Mouth-to-Nose and Mouth-to-stoma Ventilation
Mouth-to-nose ventilation is recommended if it is impossible to ventilate through the victim’s mouth (e.g., the mouth is seriously injured, the mouth cannot be opened, the victim is in water, or a mouth-to-mouth seal is difficult to achieve). Rescuer should give mouth-to-stoma rescue breaths to a victim with a tracheal stoma who requires rescue breathing.

Ventilation with Bag and Mask (Fig. 4)
Rescuers should provide bag-mask ventilation with supplemental oxygen whenever possible. Masks should be made of transparent material to allow detection of regurgitation. They should be capable of creating a tight seal on the face, covering both mouth and nose (Fig. 4).

Ventilation with an Advanced Airway
When the victim has an advanced airway in place during CPR, 2 rescuers no longer deliver cycles of CPR (i.e., compressions interrupted by pauses for ventilation). Instead, the compressing rescuer should give continuous chest compressions at a rate of 100 per minute without pauses for ventilation. The rescuer delivering ventilation provides 8 to 10 breaths per minute. The 2 rescuers should change compressor and ventilator roles approximately every 2 minutes to prevent compressor fatigue and deterioration in quality and rate of chest compressions.

5) Pulse Check (Fig. 5)
The rescuer should take no more than 10 seconds to check for a pulse. If a pulse is not definitely felt within 10 seconds, proceed with chest compressions.

6) Chest Compressions (Fig. 6)
Chest compressions consist of rhythmic applications of pressure over the lower half of the sternum. Victims of cardiac arrest need immediate chest compressions. These compressions create blood flow by increasing intrathoracic pressure and directly compressing the heart. Blood flow generated by chest compressions delivers a small but critical amount of oxygen and substrate to the brain and myocardium (Fig. 6).

Technique
To maximize the effectiveness of compressions, the victim should lie supine on a hard surface (e.g., backboard or floor), with the rescuer kneeling beside the victim’s thorax. The rescuer should compress the lower half of the victim’s sternum in the centre (middle) of the chest, between the nipples. The rescuer should place the heel of the hand on the sternum in the centre (middle) of the chest between the nipples and then place the heel of the second hand on top of the first so that the hands are overlapped and parallel. Depress the sternum approximately 1½ to 2 inches (approximately 4 to 5 cm) and then allow the chest to return to its normal position. Complete chest recoil allows venous return to the heart, necessary for effective CPR.

Compression-Ventilation Ratio (Fig. 7)
A compression-ventilation ratio of 30:2 is designed to increase the number of compressions, reduce the likelihood of hyperventilation, minimize interruptions in chest compressions for ventilation, and simplify instruction for teaching and skills retention (Fig.7).

Researchers at the 2005 Consensus Conference, reached several conclusions about chest compressions:

1. “Effective” chest compressions are essential for providing blood flow during CPR
2. To give “effective” chest compressions, “push hard and push fast.” Compress the adult chest at a rate of about 100 compressions per minute, with a compression depth of 1 to 2 inches (approximately 4 to 5 cm). Allow the chest to recoil completely after each compression, and allow approximately equal compression and relaxation times.
3. Minimize interruptions in chest compressions. Every time you stop chest compressions, blood flow stops. Every time chest compression begin again, the first few compressions are not as effective as the later compression. The more interruptions in chest compressions, the worse the victim’s chance of survival from cardiac arrest.

7) Defibrillation (Fig. 8)
When Defibrillator arrives, check rhythm. Four rhythms produce pulseless cardiac arrest: ventricular fibrillation (VF), rapid ventricular tachycardia (VT), pulseless electrical activity (PEA), and asystole. Of this ventricular fibrillation (VF) and ventricular tachycardia (VT) are shockable rhythm. VF is characterized by chaotic rapid depolarizations and repolarizations that cause the heart to quiver so that it is unable to pump blood effectively. Defibrillation “stuns” the heart, briefly stopping VF and other cardiac electrical activity. If the heart is still viable, its normal pacemakers may then resume firing and produce an effective ECG rhythm that may ultimately produce adequate blood flow. Lay rescuers can be trained to use a computerized device called an Automated External Defibrillators (AED) to analyze the victim’s rhythm and deliver a shock if the victim has VF or rapid VT. The AED uses audio and visual prompts to guide the rescuer. It analyzes the victim’s rhythm and informs the rescuer if a shock is needed. Immediate defibrillation is the treatment of choice for VF and pulseless VT (Fig. 8).

The probability of successful defibrillation decreases by approximately 7% to 10% for every minute without defibrillation. Most victims of cardiac arrest demonstrate ventricular fibrillation (VF) at some point in their arrest but by the time of first analysis the rhythm has deteriorated to asystole. Resuscitation is most successful if defibrillation is performed in about the first 5 minutes after collapse. Because the interval between call to the emergency medical services (EMS) system and arrival of EMS personnel at the victim’s side is typically longer than 5 minutes, achieving high survival rates depends on a public trained in CPR and availability of AED at public places.

CPR is important both before and after shock delivery. When performed immediately after collapse from VF cardiac arrest, CPR can double or triple the victim’s chance of survival. CPR should be provided until an automated external defibrillator (AED) or manual defibrillator is available. After about 5 minutes of VF with no treatment, outcome may be better if shock delivery (attempted defibrillation) is preceded by a period of CPR with effective chest compressions that deliver some blood to the coronary arteries and brain.

It is important that shock should be immediately followed by CPR beginning with chest compression. The rhythm analysis by current AEDs after each shock typically results in delays of 37 seconds or even longer before the delivery of the first post-shock compression which can be harmful. With most defibrillators now available, the first shock eliminates VF more than 85% of the time. In cases where the first shock fails, resumption of CPR is likely to confer a greater value than another shock.

Even when shock eliminates VF, it takes several minutes for a normal heart rhythm to return and more time for the heart to create blood flow. A brief period of chest compression can deliver oxygen and sources of energy to the heart, increasing the likelihood that the heart will be able to effectively pump blood after the shock.

The American Heart Association uses 4 links in a chain (the “Chain of Survival”) to illustrate the important time-sensitive actions for victims of VF Sudden Cardiac Arrest . These links are:

• Early recognition of the emergency and activation of the emergency medical services (EMS) or local emergency response system.
• Early bystander CPR: immediate CPR can double or triple the victim’s chance of survival from VF Sudden Cardiac Arrest (SCA).
• Early delivery of a shock with a defibrillator: CPR plus defibrillation within 3 to 5 minutes of collapse can produce survival rates as high as 49% to 75%.
• Early advanced life support followed by post resuscitation care delivered by healthcare providers.

Advanced cardiovascular support
Advanced cardiovascular support (ACLS) refers to attempts to restore spontaneous circulation with basic CPR plus advanced airway management, tracheal intubation, defibrillation, and intravenous medications. It is the 4th link of survival.
Four rhythms produce pulseless cardiac arrest: ventricular fibrillation (VF), rapid ventricular tachycardia (VT), pulseless electrical activity (PEA), and asystole. Ventricular Fibrillation (VF) is the most frequent initial rhythm documented in witnessed sudden cardiac arrest.

Ventricular Fibrillation (Fig. 9)/Pulseless Ventricular Tachycardia (Figs. 9,10).
The most critical interventions during the first minutes of VF or pulseless VT are immediate bystander CPR with minimal interruption in chest compressions and defibrillation as soon as it can be accomplished.

If VF/pulseless VT is present, providers should deliver 1 shock and then resume CPR immediately, beginning with chest compressions. If a biphasic defibrillator is available, providers should use the dose at which that defibrillator has been shown to be effective for terminating VF (typically a selected energy of 120 J to 200 J). If the provider is unaware of the effective dose range of the device, the rescuer may use a dose of 200 J for the first shock and an equal or higher shock dose for the second and subsequent shocks. If a monophasic defibrillator is used, providers should deliver an initial shock of 360 J and use that dose for subsequent shocks. Rescuer should give 5 cycles (about 2 minutes of CPR) immediately after the shock and then check the rhythm. Ideally, compression should be interrupted only for ventilation (until an advanced airway is placed), rhythm check, or shock delivery.

Once an advanced airway (e.g., endotracheal tube, oesophageal-tracheal combitube [Combitube], laryngeal mask airway [LMA]) is placed, 2 rescuers no longer deliver cycles of compressions interrupted with pauses for ventilation. Instead, the compressing rescuer should give continuous chest compressions at a rate of 100 per minute without pauses for ventilation. The rescuer delivering ventilation provides 8 to 10 breaths per minute.

Establishing IV access is important, but it should not interfere with CPR and delivery of shocks. If VF/VT persists after delivery of 1 or 2 shocks plus CPR, give a vasopressor (epinephrine every 3 to 5 minutes during cardiac arrest; one dose of vasopressin may replace either the first or second dose of epinephrine). Do not interrupt CPR to give medications.

The drug should be administered during CPR and as soon as possible after the rhythm is checked. It can be administered before or after shock delivery. Timing of drug delivery is less important than the need to minimize interruptions in chest compressions.
When VF/pulseless VT persists after 2 to 3 shocks plus CPR and administration of a vasopressor, consider administering an antiarrhythmic such as amiodarone. If amiodarone is unavailable, lidocaine may be considered. Consider magnesium for torsades de pointes associated with a long QT interval.

Pulseless Electrical Activity (Fig. 11) and Asystole (Fig. 12)
PEA encompasses a heterogeneous group of pulseless rhythms that includes pseudo-electromechanical dissociation (pseudo-EMD), idioventricular rhythms, ventricular escape rhythms, postdefibrillation idioventricular rhythms, and bradyasystolic rhythms. Research with cardiac ultrasonography and indwelling pressure catheters has confirmed that pulseless patients with electrical activity have associated mechanical contractions, but these contractions are too weak to produce a blood pressure detectable by palpation or noninvasive blood pressure monitoring. PEA is often caused by reversible conditions and can be treated if those conditions are identified and corrected. The possible causes of PEA are presented as the 6 H’s and the 6 T’s. These 6 H’s are hypovolaemia, hypoxia, hydrogen ion-acidosis, hyper-/hypokalaemia, hypothermia, hypoglycaemia and 6 T’s are tablets (drug overdose), tamponade (cardiac tamponade), tension pneumothorax, thrombosis (coronary), thrombosis (pulmonary) and trauma. Information from the ECG, the history, and the physical examination can be used to identify possible diagnoses. If rescuer can identify the specific condition and treat appropriately, cardiac arrest can be reversed.

The survival rate from cardiac arrest with asystole is dismal. During a resuscitation attempt, brief periods of an organized complex may appear on the monitor screen, but spontaneous circulation rarely emerges. As with PEA, the hope for resuscitation is to identify and treat a reversible cause.

When the rhythm check confirms asystole or PEA, resume CPR immediately. A vasopressor (epinephrine or vasopressin) may be administered at this time. Epinephrine can be administered approximately every 3 to 5 minutes during cardiac arrest; one dose of vasopressin may be substituted for either the first or second epinephrine dose. For a patient in asystole or slow PEA, consider atropine. Do not interrupt CPR to deliver any medication. Give the drug as soon as possible after the rhythm check.
After drug delivery and approximately 5 cycles (or about 2 minutes) of CPR, recheck the rhythm. If a shockable rhythm is present, deliver a shock. If no rhythm is present or if there is no change in the appearance of the electrocardiogram, immediately resume CPR.

Patients who have either asystole or PEA will not benefit from defibrillation attempts. The focus of resuscitation is to perform high-quality CPR with minimal interruptions and to identify reversible causes or complicating factors.

ACLS Pulseless Arrest Algorithm
Not all adult deaths are due to SCA and VF. An unknown number have an asphyxial mechanism, as in drowning or drug overdose. Asphyxia is also the mechanism of cardiac arrest in most children, although about 5% to 15% have VF. Best results for resuscitation from asphyxial arrest are obtained by a combination of chest compressions and ventilations, although chest compressions alone are better than doing nothing.

It is of utmost importance to start resuscitation as soon as possible to improve survival. The developed countries have well established Emergency Medical Services who reach to the person when alerted in shortest possible time. Also the lay person is aware of the basic skills of resuscitation. Unfortunately in India even the Health Care Workers are not well trained. It is important that all of us should be trained in CPR skills and also upgrade knowledge and skills time to time to remain aware with recent guidelines. This will bring order and organization to the treatment of cardiac arrest. Resuscitation attempts are complex emotional and professional challenges. The more your thinking becomes automatic, the better you will respond.