During a cardiac arrest, this mnemonic helps you think through potential etiologies. In some cases, unless the underlying cause of the cardiac arrest is identified and addressed, the patient may not recover. These “5 Hs and Ts” are:

The Hs

  • Hypoxia
  • Hypovolemia
  • Hypokalemia
  • Hyperkalemia
  • Hypothermia
  • Hydrogen (i.e. profound acidosis)

The Ts

  • Toxins
  • Trauma
  • Tamponade (cardiac)
  • Tension pneumothorax
  • Thrombosis (i.e. pulmonary embolism, coronary artery plaque rupture)