The “H’s and T’s” refer to a mnemonic used in medicine to help healthcare professionals quickly recall the most common causes of cardiac arrest during a code (a medical emergency requiring CPR). Memorizing these is crucial because identifying and addressing these causes rapidly can improve the chances of saving a patient’s life.

Here’s a breakdown:

The H’s: OK TV

Hypoxia - Lack of oxygen to tissues can lead to a heart stopping, so ensuring proper oxygenation is key.

Hypo-/Hyperkalemia - Abnormal potassium levels affect the heart’s electrical activity, potentially causing it to stop.

Hypothermia - Low body temperature can slow heart function and lead to cardiac arrest.

Hypovolemia - Loss of blood or fluids can lead to insufficient circulation and cardiac arrest.

Hydrogen ion (acidosis) - A build-up of acid in the blood (often due to respiratory failure or shock) can disrupt heart function.

The T’s: THROW TEN TOXIC TAMPONS

Thrombosis (pulmonary or coronary) - Blood clots in the lungs (pulmonary embolism) or heart (myocardial infarction) can obstruct blood flow, leading to cardiac arrest.

Tension Pneumothorax - Air trapped in the chest cavity compresses the heart and lungs, affecting circulation.

Toxins - Certain substances (medications, drugs, poisons) can disrupt heart rhythms.

Tamponade (cardiac) - Accumulation of fluid around the heart prevents it from pumping effectively.

Importance of Memorizing the H’s and T’s:

These causes cover many reversible conditions that may lead to cardiac arrest. During a code, time is critical, so having these potential causes at the top of your mind helps quickly assess and treat the patient. Remembering the “H’s and T’s” mnemonic ensures that a healthcare provider methodically works through possible causes and provides the best chance of resuscitation.