CPR Techniques May Require an Over Haul to Improve Survival

It is estimated that 900 Americans a day have a cardiac arrest (i.e. the heart stops beating). A very dangerous situation! Knowledge of CPR may be able to save a life, if applied correctly.

CPR: Small acronym for Cardio-Pulmonary Resuscitation. Everyone should be educated in how to apply CPR, as 75% of cardiac arrests occur at home.

Some form of resuscitation has probably existed for thousands of years. Witness the many examples in the Bible where it states someone breathes life into another. This breath of life is probably analogous to our current ‘rescue breaths’ given during a respiratory arrest, or as part of CPR.

Our current form of CPR originated in the late 60’s. CPR is one step in what is called the chain of survival for people with cardiac arrest, and consists of chest compression plus mouth-to-mouth ventilations. With only slight modification, no changes have been made since the 60’s.

However, to be effective, various criteria must be met. The number one criterion is that someone must witness the arrest. In 50% of cases, the arrest goes unwitnessed. If there are 900 arrests per day that would mean 450 people per day have a cardiac arrest that is not observed by anyone.

The second criterion is that the person who witnesses the arrest, or the by passer must attempt CPR. It is estimated that of the 50% of arrests witnessed, only 1/3 have CPR. Various reasons partially explain why this omission occurs:

• Fear of transmission of HIV (although no such cases exist, where this occurred)

• Fear of legal ramifications (although Good Samaritan laws exist in every state to protect the rescuer)

• Complexity of the CPR technique currently taught

The third criterion is that CPR must be performed correctly. Many times this does not occur, even with trained medical personnel.

• Rescue breaths do not inflate the lungs, but do inflate the stomach, contributing to the vomiting which frequently occurs during CPR

• In the chain of survival, the rescuer is to obtain a pulse. In the greater majority of cases, even with trained medical personnel, the pulse is not felt when present, or is felt when not present.

The fourth criterion is that the heart must be in ventricular fibrillation (i.e. a quivery rhythm). CPR does not stop VF but does extend the window of opportunity to make defibrillation effective. VF is fatal unless an electric shock is given. Most people will recognize this type of shock from hospital shows currently on TV, such as ER. When the word ‘clear’ is shouted, defibrillation is being given (or an electric shock to the heart, to regulate the heart beat). Defibrillation must be applied within 10-12 minutes of the arrest; otherwise, the heart gradually becomes exhausted and quits.

Fifth, CPR must be started within 4 minutes of the collapse; otherwise, neurological damage will occur.

It is easy to see, why most cardiac arrests result in death, when one realizes all the criterion which must be met for the person to survive.

However, a recent study which was initiated in Japan provides more hope for the future for the hapless victims of cardiac arrest. In this study, the results indicated that 20% vs 10% of people survived arrest with no neurological complications, when heart compressions only applied. Many possible reasons were cited for this improved survival:

• If the airway is open, gasping breathing and passive chest movements during compression provide some air exchange. NOTE: Irrespective of ventilation attempts, arterial oxygenation decreases after 4-10 minutes of CPR

• Bystanders are more likely to perform chest compressions, if mouth to mouth breathing is not included

• Lung pressure drops after each pause for mouth-to-mouth breathing, and several chest compressions have to be done before previous rates of blood flow to the heart and brain return (NOTE: This is a critical fact, as the blood flow, even with compressions, is only 20-30% of normal; or a trickle of blood flow)

• Rescue breathing is only effective if respiratory arrest (i.e. breathing stops, but not the heart). This occurs in drowning, electrocution, some drug overdoses, or suffocation. As noted above, most people can not discern respiratory from cardiac arrest, as the pulse is not interpreted correctly.

The American Heart Association stated they will not change their guidelines at this time, as they already note that if a bystander is unwilling or unable to provide mouth to mouth, chest compressions only can be used. Additionally, many more studies were advocated before definitive conclusions can be drawn.

The American Heart Association, March, 2007