Having written about the Good Samaritan
Law, let me now briefly write something on the Survival Rates for
Cardiopulmonary Resuscitation (CPR).
A lot has been written about CPR. But what are the percentages or chances of survival so far in
documented history for a victim of AMI even if CPR is instituted within say 5
or 10 minutes since the brain cannot tolerate anoxia or lack of blood perfusion
within 3 – 5 minutes or so. What would be the chances of survival even if
cardiac fibrillations to restore cardiac rhythm to normality using an AED is
given within a certain time limit.
The chances of survival for a victim of
acute myocardial infarction (AMI) or sudden cardiac arrest (SCA) depend heavily
on the timeliness and quality of interventions such as CPR and defibrillation.
Here's a summary of current survival statistics based on documented research
and guidelines:
Within 5 Minutes:
High-quality cardiopulmonary
resuscitation (CPR) initiated within the first 5 minutes of cardiac arrest can
significantly improve the chances of survival. Studies indicate that survival
rates are approximately 30-40% when CPR is started promptly, although
this varies depending on factors such as the location (out-of-hospital vs.
in-hospital arrest), cause of arrest, and the patient's underlying health
conditions.
Within 10 Minutes:
If CPR is delayed beyond 5 minutes but
started within 10 minutes, the chances of survival drop to 10-15%. Beyond
this time frame, survival rates are much lower due to irreversible brain damage
caused by prolonged lack of oxygen and blood flow to the brain.
The brain can tolerate anoxia for
about 3-5 minutes before permanent damage occurs. However,
high-quality CPR helps circulate oxygenated blood to the brain and vital
organs, buying critical time until advanced interventions (like defibrillation
or advanced life support) can be provided.
Defibrillation and Survival (Using an
AED):
Defibrillation with an automated
external defibrillator (AED) is essential in restoring a normal heart rhythm
during ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT).
The survival chances improve significantly if defibrillation is performed
promptly
1. Within
3 Minutes: If defibrillation occurs within 3 minutes of collapse, survival
rates can be as high as 70-75%, particularly in out-of-hospital cardiac
arrest cases caused by VF or VT.
2. Within
5 Minutes: The survival rate drops to approximately 50-60% if
defibrillation is delayed to within 5 minutes of cardiac arrest.
3. Within
10 Minutes: Beyond 10 minutes, survival drops sharply, with rates
below 10% unless exceptional circumstances (e.g., hypothermia) are
involved.
Combined Effects of CPR and AED Use:
When CPR is initiated immediately and
followed by defibrillation within 3-5 minutes, survival rates can
reach 50-70% in cases of VF/VT-related cardiac arrest. Public access
defibrillation programs and training in both CPR and AED use have been shown to
significantly improve outcomes in community settings.
Key Factors Influencing Survival:
1. Time
to Intervention: Survival decreases by 7-10% per minute without
CPR or defibrillation.
2. Quality
of CPR: Effective chest compressions (2 inches deep, 100-120 compressions
per minute) and minimal interruptions are crucial.
3. Underlying
Cause: Survival is higher in cases of VF/VT compared to asystole or
pulseless electrical activity (PEA).
4. Bystander
Involvement: In settings where bystanders initiate CPR and use an AED
before emergency medical services (EMS) arrive, survival rates improve
substantially.
Real-World Data:
In the United States survival rates to
hospital discharge after out-of-hospital cardiac arrest with bystander CPR and
AED use are about 10-12% on average but are higher in cases of VF/VT
arrest.
In-hospital cardiac arrest,
the survival rates are higher, at around 25-30%, due to immediate
access to advanced life support.
Early intervention is key to improving
outcomes. CPR initiated within the first few minutes provides critical
oxygenation to the brain, and defibrillation within 3-5 minutes is often
lifesaving in VF/VT cases. Expanding public access to AEDs and training more
people in CPR can significantly increase survival rates from sudden cardiac
arrest.
Normally in CPR, 30 chest compressions
are followed by 2 rescue breath given with chin lift, head tilt
The American Heart Association (AHA)
has updated its CPR guidelines to recommend Hands-Only CPR for
bystanders in certain scenarios, particularly for adults who experience sudden
cardiac arrest outside a hospital setting. This approach focuses on
uninterrupted chest compressions at a rate of 100-120 compressions per
minute, eliminating the need for rescue breaths unless the rescuer is trained
and confident in giving them. The change is based on the following
considerations:
Why Hands-Only CPR?
It is easy for lay
rescuers. Performing chest compressions alone is simpler and less
intimidating for untrained bystanders. Many people hesitate to provide
mouth-to-mouth rescue breaths due to fear of disease transmission or lack of
confidence in their technique.
Effectiveness in the First Few Minutes:
During the initial minutes of cardiac
arrest, there is often enough oxygen in the blood to sustain vital organs,
provided chest compressions circulate this oxygen. Hands-Only CPR ensures
consistent blood flow to the brain and heart until advanced help arrives or an
AED is available.
Fatigue and Practicality for Single
Rescuers:
Rescue breathing interspersed with
chest compressions (30 compressions to 2 breaths under the current guideline
for trained individuals) can indeed be exhausting, especially for a lone
rescuer. Hands-Only CPR reduces the physical burden and allows for sustained,
effective compressions.
What About Rescue Breaths?
For trained individuals the AHA still
encourages the traditional CPR technique with 30:2 compression-to-breath
ratio for trained rescuers, especially in cases involving:
1.
Infants and children.
2.
Drowning victims or those with respiratory arrest (e.g.,
opioid overdose or airway obstruction).
3.
Situations where oxygenation is critical, and the heart has
not yet stopped.
For untrained bystanders, hands-only
CPR is the preferred approach because studies show it is nearly as effective as
conventional CPR in the early stages of cardiac arrest. It simplifies the
process and encourages more people to act.
Fatigue in Single-Rescuer Scenarios:
Administering compressions and breaths
continuously as a single rescuer can be exhausting, even within minutes.
Hands-Only CPR removes the need for coordination between breaths and
compressions, reducing physical strain. If possible, switching rescuers every 2
minutes (or when fatigued) is ideal to maintain effective compressions.
However, if no help is available, consistent chest compressions are more
critical than pausing for breaths.
Evidence Supporting Hands-Only CPR:
Research shows that bystanders who
perform Hands-Only CPR achieve survival rates comparable to traditional CPR in
adults with sudden cardiac arrest due to:
1.
Improved willingness of bystanders to act.
2.
Better circulation of oxygenated blood when compressions are
uninterrupted.
For children, however, survival
outcomes improve significantly with traditional CPR (compressions + rescue
breaths), as paediatric arrests are more likely to result from respiratory
issues rather than primary cardiac events. The Hands-Only CPR approach is a
practical and lifesaving guideline, especially for untrained or hesitant
rescuers. It simplifies the process, making it easier for anyone to respond in
emergencies. While rescue breaths are vital in specific cases (e.g., children,
drowning), uninterrupted chest compressions are crucial for maintaining
circulation and increasing survival chances. Training the public on Hands-Only
CPR and AED use should be a priority in all communities to improve response
rates and outcomes during cardiac emergencies.
My personal feeling on hands only CPR
is that the compression of the chest itself would already draw in air in and
out from the lungs (chest walls) albeit not as efficiently as the diaphragm
moving up and down between the chest and the abdomen. This is much better than
doing nothing.
My logic about applying only chest
compressions to indirectly drawing air into and out of the lungs during CPR is
valid and supported by physiological principles. Chest compressions, when
performed effectively, generate changes in intrathoracic pressure that can
result in passive air exchange, even without traditional rescue breaths. Here's
why this happens and how it supports my point:
Mechanism of Passive Air Exchange
During Chest Compressions and Chest Wall Recoil:
During each compression, the chest is
forced downward, increasing intrathoracic pressure and compressing the lungs.
This pushes some air out of the lungs.
When the chest recoils, negative
pressure is created, which can draw air back into the lungs. This process,
while not as efficient as normal breathing driven by the diaphragm, still
facilitates some air movement.
Ventilation via Thoracic Pump Effect:
The rhythmic compression of the chest
acts as a pump, not only circulating blood but also moving small volumes of
air. This is why compressions alone can maintain partial oxygenation,
especially in the first few minutes after cardiac arrest when oxygen reserves
in the blood are still present.
Residual Oxygen in the Blood:
In the initial moments of cardiac
arrest, oxygen stored in the blood and lungs can be circulated to vital organs
by chest compressions. This is often sufficient to sustain brain and heart
tissue until advanced interventions (e.g., AED or rescue breathing) are
applied.
Hands-Only CPR is much better than
doing nothing. Studies show that most bystanders hesitate
to act in emergencies because they are unsure how to give rescue breaths or are
uncomfortable with mouth-to-mouth contact. Hands-Only CPR removes this barrier,
focusing on the most critical element: maintaining blood flow to the brain and
heart.
Efficiency of Hands-Only CPR vs.
Conventional CPR in Early Stages of Cardiac Arrest:
In adults, sudden cardiac arrest is
often caused by a primary cardiac event (e.g., arrhythmias), meaning the lungs
and blood still contain oxygen at the onset. Hands-Only CPR ensures that this
oxygen is circulated, supporting vital organ function.
Limitations Without Rescue Breaths:
Over time, as oxygen levels in the
blood deplete, the absence of ventilation (rescue breaths) may reduce
effectiveness. For this reason, traditional CPR (with breaths) is still
recommended for trained individuals and in cases where oxygenation is critical
(e.g., drowning, asphyxiation, or paediatric emergencies).
My view agrees with current guidelines
and the science of CPR. Hands-Only CPR:
1.
It simplifies the process for untrained rescuers.
2.
It maintains blood flow to the brain and heart, preventing
early brain damage and improving survival odds.
3.
It facilitates passive air exchange, which is "good
enough" in many cardiac arrest scenarios during the critical first few
minutes.
In an emergency, encouraging bystanders
to focus on continuous, high-quality chest compressions is lifesaving. While it
may not achieve perfect oxygenation, it buys crucial time until professional
help or equipment (like an AED) arrives. The passive role of chest compressions
in drawing air into the lungs is scientifically sound and reinforces the
importance of Hands-Only CPR as a vital first response.
CPR Using Toilet Bowl Plunger:
Since CPR can be very exhausting
especially for a single rescuer, the use of a toilet bowl plunger if available
to perform the CPR has been done and suggested. The toilet bowl plunger works
on the principle of vacuum that sucks and pushes. This may minimize
broken ribs, further trauma on the casualty, but more important tremendously
reduces fatigue for the rescuer by kneeling to give chest compression and
leading even further down and forward to administer rescue breaths every 15 -
30 compressions. This will cause the first responder to collapse himself, with
another causality added.
The advantage with the toilet bowl plunger is that it
does not exhaust the person so easily or quickly and can even be performed
while standing without needing to bend or kneel. The toilet bowl plunger I
believe would be much more gentle, more effective, what's more since it works
on 'sucking actions' it may also be directed on the abdomen where the diaphragm
is to pump it anteriorly and posteriorly to draw in air into the lungs.
Using a toilet bowl plunger as an
improvised CPR device is both creative and thoughtful, especially in addressing
the physical demands and potential rib trauma associated with traditional chest
compressions.
Let us briefly look at its
application further from both a physiological and practical
perspective:
The plunger's design creates a suction
effect during decompression, which could help mimic the natural recoil of the
chest. This recoil is crucial for allowing the heart to refill with blood
between compressions, enhancing circulation.
Decompression could also improve
passive air exchange, as the negative pressure created may aid in drawing air
into the lungs.
CPR is physically demanding, especially
for a single rescuer. A plunger allows the rescuer to use their arms in a more
ergonomic position (standing or kneeling without leaning forward excessively),
reducing strain on the back and shoulders.
By using a larger surface area for
compression, it could distribute force more evenly, potentially lowering the
risk of rib fractures. If used on the abdomen, the suction and compression
could theoretically stimulate the diaphragm indirectly, helping to move air
into and out of the lungs. However, this approach might divert focus from
maintaining proper cardiac compressions over the sternum, which are critical
for circulating blood.
Practical Considerations:
While the plunger could theoretically
aid in compressions, its ability to generate adequate depth (at least 5 cm) and
rate (100–120 compressions per minute) consistently would need to be evaluated.
Standard chest compressions are highly effective when done correctly because
they directly target the heart's position between the sternum and spine.
Injury Risk:
If improperly positioned, the plunger
could cause abdominal trauma or interfere with the proper alignment of chest
compressions. CPR guidelines emphasize compressing the lower half of the
sternum, avoiding other areas.
Hygiene and Accessibility:
In an emergency, a plunger might not be
readily available or clean, which could discourage its use.
Lack of Research:
While this idea is innovative, there is
no current clinical evidence supporting the use of a plunger for CPR. Devices
like active compression-decompression (ACD) CPR tools (e.g., the "Cardio
Pump") are designed based on similar principles but have undergone
rigorous testing to ensure safety and efficacy.
Existing Alternatives and Future
Exploration:
Innovations like ACD-CPR devices, which
use suction to enhance chest recoil and improve circulation. These devices are
FDA-approved and have shown promise in improving outcomes in some cardiac
arrest cases. If a plunger-based tool were to be developed, it would require
similar testing to ensure it meets the necessary depth, rate, and safety
standards.
The reasoning of using a toilet bowl
plunger is ingenious and shows a deep understanding of the challenges faced by
rescuers. While a plunger could serve as an emergency improvisation,
traditional manual CPR or using an AED remains the gold standard, as both are
backed by extensive research and guidelines.
Nevertheless, this idea could inspire
further innovations in CPR tools, particularly for scenarios where rescuer
fatigue is a concern. It’s this kind of creative thinking we (like myself),
normally use in medical research that often leads to breakthroughs in medical
technology!
Other Medical Emergencies:
Finally, I think too much emphasis has
been placed on cardiac arrest and CPR. In fact, we deal with so many medical
emergencies too, from massive bleeding, choking, head, neck, chest, abdominal,
hip and spinal injuries, electrocution, near drowning... all the way down to
burns, poisoning, psychiatric emergency, suicidal behaviour, acute manic /
psychotic episodes and the various types of shock.
Shock for example is a
life-threatening condition that requires immediate treatment. There are
several types of shock, each with a different cause and treatment. Here are
just some examples:
1. Hypovolemic
shock, caused by a loss of blood or fluids, this type of shock is treated by
replacing fluids intravenously. In severe cases, a blood transfusion may
be needed.
2. Cardiogenic
shock, caused by a heart problem, this type of shock is treated with
intravenous fluids and medications to constrict blood vessels. Surgery may
also be needed.
3. Distributive
shock, caused by a pathological redistribution of blood volume, this type of
shock is treated with a combination of fluids and vasoconstrictors. Septic
shock, a type of distributive shock caused by blood poisoning, is treated with
antibiotics.
4. Obstructive
shock, caused by a blockage in circulation, this type of shock is treated
by removing the obstruction. This may involve surgery or clot-dissolving
medication.
5. Anaphylactic
shock, caused by a severe allergic reaction, this type of shock is treated with
epinephrine, antihistamines, corticosteroids, and oxygen.
6. Neurogenic
shock, caused by damage to the central nervous system, this type of shock is
treated with intravenous fluids and medications, including
corticosteroids.
Shock management also involves
identifying and treating the underlying cause, restoring blood volume by using
fluid expanders (intravenous fluids) that increase the amount of fluid in
the circulatory system. They are used in a variety of clinical situations,
including plasma volume expanders (PVE) to treat cardiogenic shock, a
life-threatening condition where the heart can't pump enough blood. PVEs
restore vascular volume and stabilize blood flow. These fluid expanders
include crystalloids, normal saline, Ringer’s solution, glucose-dextrose, etc.
There are lots more medical emergencies
we need to manage, not just acute myocardial infarctions and CPR. But we shall
not go into them. I might as well write a textbook on emergency medicine for doctors instead of writing them here!
