Cardiopulmonary resuscitation (CPR) is a critical intervention performed when someone’s heart or breathing stops, aiming to circulate oxygen-rich blood to the brain and other organs. While CPR is a life-saving technique, it is not always successful. Understanding its limitations helps manage expectations and highlights areas for improvement in emergency response.
The Impact of Delayed Response
The immediate initiation of CPR significantly influences survival chances during sudden cardiac arrest. Brain cells begin to die within minutes of oxygen deprivation, with severe and potentially irreversible injury risk becoming high around five minutes. Every minute without CPR reduces the likelihood of survival.
Bystander hesitation often contributes to critical delays in starting CPR. People may hesitate due to uncertainty, fear of causing harm, or waiting for professional help. This psychological phenomenon, known as the bystander effect, can lead to a diffusion of responsibility, where individuals assume someone else will intervene. Such delays can substantially decrease resuscitation effectiveness.
Promptly calling emergency services is also crucial. Even if untrained, a 911 dispatcher can guide a bystander through CPR steps until first responders arrive. A delay of 2 to 3 minutes in bystander CPR can make a patient 9% less likely to survive to hospital discharge, and a delay of 4 to 5 minutes can make them 27% less likely.
Challenges with CPR Execution
The quality of CPR execution directly impacts its effectiveness; improper technique significantly reduces success rates. Insufficient compression depth is a common error, failing to generate enough pressure to circulate blood to vital organs. For adults, compressions should be about 2 to 2.4 inches (5 to 6 cm) deep.
Incorrect hand placement further compromises the effectiveness of chest compressions. Placing hands too high, too low, or not centered can lead to ineffective blood circulation and may also increase the risk of injuries such as rib fractures. The heel of one hand should be placed in the center of the chest, between the nipples, with the other hand on top.
An inadequate compression rate also hinders effective blood flow. Compressions should be delivered at 100 to 120 per minute. Leaning on the chest between compressions prevents full chest recoil, which is essential for the heart to refill. Incomplete recoil reduces blood return to the heart, limiting the amount of blood available for subsequent pumps.
Patient’s Pre-existing Conditions
An individual’s underlying health status significantly influences CPR success. CPR is primarily designed to reverse sudden cardiac arrest, not to cure long-standing or terminal illnesses. Patients with severe pre-existing medical conditions often have lower survival rates after CPR.
Conditions like advanced heart disease, chronic respiratory conditions, multi-organ failure, and terminal illnesses make resuscitation challenging. Cancer patients generally have lower survival rates following CPR compared to those with other conditions. The presence of multiple chronic health conditions and a low pre-CPR functional status also reduce survival rates.
CPR attempts in these situations may temporarily restore cardiac function but often do not lead to long-term survival or a return to a previous quality of life. The severity and type of illness, along with functional dependence, are factors that affect the likelihood of a positive outcome.
The Role of Advanced Support
Basic CPR, involving chest compressions and rescue breaths, serves as a temporary measure to maintain blood flow and oxygen to vital organs. For definitive treatment and long-term survival, advanced medical interventions are essential. These typically include defibrillation, advanced airway management, and medications administered by paramedics or hospital staff.
An Automated External Defibrillator (AED) is particularly important for many cardiac arrest cases. An AED analyzes the heart’s rhythm and delivers an electrical shock to restore a normal heartbeat if needed. For every minute without defibrillation, the chance of survival can decrease by 7 to 10 percent. Combining bystander CPR with early AED use significantly increases survival rates.
CPR buys time until these advanced life support measures can be applied. While chest compressions manually pump blood, they cannot correct the underlying electrical problem in the heart that causes many cardiac arrests. The absence or delay of these advanced medical interventions, even after effective basic CPR, can ultimately lead to an unsuccessful resuscitation effort.