Cardiovascular Collapse

What to do if someone collapses

1. Check for danger, then check whether they respond: tap their shoulders and shout.
2. Call 911 or your local emergency number if they do not respond. Put the phone on speaker. The dispatcher will guide you.
3. Check breathing for no more than 10 seconds. Occasional gasps are not normal breathing.
4. If they are not breathing normally, start CPR: push hard and fast in the center of the chest, at least 5 cm (2 inches) deep, 100 to 120 times a minute. Hands-only CPR is fine if you are not trained in rescue breaths.
5. Send someone for an AED (automated external defibrillator). Turn it on and follow the spoken instructions.
6. If they are breathing, roll them onto their side (the recovery position), keep them warm and watch their breathing until help arrives.
7. If anaphylaxis is likely, give their epinephrine auto-injector into the outer thigh.

How cardiovascular collapse happens

Blood pressure depends on three things: the heart pumping, enough blood volume, and blood vessels with enough tone to keep pressure up. Cardiovascular collapse happens when one or more of these fails suddenly. The brain is the most sensitive organ to a drop in blood flow. Consciousness is lost within about 10 seconds of the circulation stopping, and permanent brain damage can start after a few minutes.

Doctors describe the forms by how long and how severe the failure is:

Causes

Heart causes

• Arrhythmias: dangerous rhythms such as ventricular fibrillation, the most common cause of sudden cardiac arrest. Very slow rhythms (heart block) can also cause collapse.
• Heart attack: can trigger an arrhythmia or weaken the pump, causing cardiogenic shock.
• Structural heart disease: severe aortic stenosis, hypertrophic cardiomyopathy and heart failure.

Obstruction of blood flow

• Pulmonary embolism: a large clot blocks blood flow through the lungs.
• Cardiac tamponade: fluid or blood around the heart squeezes it.
• Tension pneumothorax: air trapped in the chest presses on the heart and great vessels.

Loss of blood volume

• severe bleeding from injury, a ruptured aortic aneurysm, a stomach ulcer or an ectopic pregnancy
• severe dehydration from vomiting, diarrhea or heat

Blood vessels losing their tone (distributive shock)

• Anaphylaxis: a severe allergic reaction widens blood vessels and leaks fluid.
• Sepsis: the body's response to infection causes widespread vessel dilation.
• Spinal cord injury and some poisonings or overdoses.

Reflex fainting

The most common and least dangerous cause. A trigger (pain, standing for a long time, heat, the sight of blood) causes the heart rate and blood pressure to drop briefly. This is vasovagal syncope.

Warning signs

Some people collapse with no warning, especially with arrhythmias. Others have warning signs minutes to hours before:

• chest pain, palpitations or a racing heart
• severe breathlessness
• lightheadedness, tunnel vision or nausea
• pale, gray, cold or clammy skin
• confusion, restlessness or anxiety
• fast, weak pulse and fast breathing
• in anaphylaxis: hives, swelling and wheezing
• in sepsis: fever or low temperature, shivering and feeling very unwell

How it is diagnosed in hospital

Emergency teams treat first and investigate in parallel. They will check heart rhythm with an ECG and monitor, blood pressure and oxygen levels. Blood tests include troponin (heart damage), lactate (a marker of poor blood flow to organs), blood count, electrolytes and cultures for infection. Bedside ultrasound of the heart can quickly show tamponade, a weak pump or strain from a clot. Later tests may include echocardiography, CT scans and longer heart rhythm monitoring.

Treatment

• Cardiac arrest: CPR and defibrillation, then medicines such as epinephrine, and treatment of the cause, for example opening a blocked heart artery.
• Shock: intravenous fluids or blood, medicines to raise blood pressure (vasopressors), oxygen and intensive care.
• Anaphylaxis: intramuscular epinephrine, fluids and further doses as needed.
• Sepsis: antibiotics within the first hour and fluids.
• Pulmonary embolism: clot-dissolving medicines or clot removal for large clots.
• Arrhythmias: medicines, pacemakers or implantable defibrillators (ICDs) to prevent future episodes.

Outlook

Outlook depends on the cause and how quickly help arrives. Simple faints carry an excellent outlook. For cardiac arrest outside hospital, overall survival is low, but bystander CPR and early defibrillation can double or triple the chance of survival. People who survive shock or arrest often need rehabilitation and follow-up with a cardiologist.

Frequently asked questions

What is cardiovascular collapse?

It is a sudden failure of the heart or blood vessels to keep blood flowing to the brain and organs. The person usually loses consciousness and falls. It covers a range from a simple faint to shock and cardiac arrest, which is the most serious form.

What is the difference between cardiovascular collapse and cardiac arrest?

Cardiac arrest is one type of cardiovascular collapse, where the heart stops pumping effectively and there is no pulse. Collapse can also happen with a working heart, for example in a faint, anaphylaxis or blood loss, where blood pressure falls too low.

What causes sudden circulatory collapse?

The main causes are dangerous heart rhythms, heart attack, severe bleeding, severe allergic reactions, sepsis, large blood clots in the lungs, and fluid around the heart. The most common cause of a brief collapse is a simple faint triggered by standing, heat or pain.

Should I do CPR if I am not trained?

Yes. If an adult collapses and is not breathing normally, call 911 and push hard and fast in the center of the chest, 100 to 120 times a minute. Hands-only CPR is effective, and the dispatcher can coach you. An AED will tell you exactly what to do.