Cardiopulmonary Resuscitation (CPR) is a life-saving technique used when a person’s heart stops beating, aiming to maintain blood flow to the brain and other organs until professional help arrives. Historically, CPR involved both chest compressions and mouth-to-mouth rescue breaths. Public guidance has shifted significantly, leading to the widespread promotion of “Hands-Only CPR” for bystanders. The medical consensus recognizes that prompt action is paramount, and a simplified method increases the likelihood of immediate bystander intervention.
Defining Hands-Only CPR
Hands-Only Cardiopulmonary Resuscitation (HOCPR) is a simplified technique involving continuous, rapid chest compressions without pausing for rescue breaths. This method focuses entirely on maintaining circulation by pushing hard and fast in the center of the victim’s chest. The process begins with calling the local emergency number, followed immediately by initiating chest compressions.
The quality of compressions is precisely defined to maximize blood flow. For an adult victim, the recommended rate is between 100 and 120 compressions per minute. Each compression should achieve a depth of at least two inches, but not exceed 2.4 inches, on the breastbone. This technique is designed to be less intimidating and easier for an untrained rescuer to perform without hesitation.
Conventional CPR requires the rescuer to alternate between chest compressions and rescue breaths, typically at a 30:2 ratio. The compression-only approach eliminates the need for mouth-to-mouth contact, which has historically been a barrier to bystander intervention due to concerns about disease transmission.
Measuring Effectiveness: Hands-Only Versus Conventional CPR
Research indicates that for sudden out-of-hospital cardiac arrests (OHCA) witnessed by a bystander, Hands-Only CPR can be equivalent to, or in some cases superior to, conventional CPR. The American Heart Association (AHA) supports HOCPR for lay rescuers responding to adult collapse. Studies show that when performed by an untrained person, the simplified technique often results in better patient outcomes.
HOCPR increases the rate of bystander action, which is the most important factor in improving OHCA survival rates. When bystanders are only required to perform compressions, they are more likely to act quickly, minimizing delay until professional help arrives. This immediate intervention can nearly double or triple a person’s chance of survival.
Survival to hospital discharge for victims receiving HOCPR has been reported in a range of 4% to 15%, comparing favorably with conventional CPR in similar scenarios. Neurologically favorable survival can be slightly higher with HOCPR compared to conventional CPR performed by a bystander. This improved outcome is primarily due to the reduction in interruptions, as eliminating the pause for rescue breaths ensures more consistent blood flow to the brain and heart.
Situations When Hands-Only CPR is Recommended
Hands-Only CPR is recommended for adults who suddenly collapse and are not breathing normally, particularly when the cause is a primary cardiac problem. This includes the majority of adult cardiac arrests occurring in public or at home, typically caused by an electrical malfunction in the heart. In these instances, the victim has adequate oxygen reserves in their bloodstream for the first few minutes, making continuous circulation the priority.
When cardiac arrest is likely due to a respiratory cause, such as drowning, opioid overdose, or prolonged smoke inhalation, the guidance changes. In these asphyxial arrests, the body’s oxygen supply is depleted immediately, requiring oxygen delivery in addition to circulation. For these specific scenarios, especially in pediatric arrests where respiratory issues are common, conventional CPR with rescue breaths is the preferred method.
A lay rescuer who is trained and confident in performing the 30:2 compression-to-breath ratio should use conventional CPR in all situations. If an untrained bystander is unwilling or unable to deliver rescue breaths, HOCPR is still far better than doing nothing at all. The simplified technique ensures that life-sustaining circulation is provided until emergency medical services take over.
The Physiological Basis for Compression-Only Resuscitation
The effectiveness of compression-only resuscitation is rooted in the physiological state of an adult experiencing sudden cardiac arrest from a primary heart event. When the heart stops, the lungs and blood still contain a reserve of oxygen, which is often sufficient for the first four to six minutes of the emergency. This residual oxygen is important for sustaining the brain and heart until defibrillation or advanced care can be administered.
Chest compressions act as a mechanical pump, artificially squeezing the heart between the sternum and the spine to generate blood pressure. This action propels the existing oxygen-rich blood to the body’s most sensitive organs, particularly the brain and the coronary arteries of the heart muscle itself. Minimizing interruptions ensures that the pressure generated by the compressions remains high, which is necessary to overcome the resistance in the blood vessels and perfuse the tissues.
Allowing the chest to fully recoil after each compression is equally important, as this creates a negative pressure inside the chest cavity. This negative pressure draws blood back into the heart chambers, preparing them to be pumped out again with the next compression. Focusing solely on continuous mechanical circulation, HOCPR maximizes the delivery of the patient’s remaining oxygen supply, buying precious time for survival.