What is 5 HS and 5 TS?
The "5 Hs and 5 Ts" are a crucial mnemonic used in emergency medicine to remember the most common reversible causes of pulseless arrest. This structured approach helps healthcare professionals quickly identify and address underlying factors contributing to a patient's cardiac arrest, which is vital for improving patient outcomes.
This mnemonic is a cornerstone of advanced cardiac life support (ACLS) protocols, guiding systematic assessment and intervention during critical medical emergencies.
The 5 Hs
These factors typically relate to internal physiological imbalances or environmental conditions that can profoundly affect the body's ability to maintain vital functions, potentially leading to cardiac arrest.
| Factor | Description |
|---|---|
| Hypovolemia | An insufficient volume of blood or other fluid in the circulatory system, often due to severe fluid loss. |
| Hypoxia | A state where the body or a region of the body is deprived of adequate oxygen supply. |
| Hydrogen Ion (Acidosis) | An excess of acid in the body fluids, leading to a decreased pH level and metabolic dysfunction. |
| Hyper-/Hypokalemia | Imbalances in potassium levels in the blood: either dangerously high (hyperkalemia) or dangerously low (hypokalemia). |
| Hypothermia | A condition in which the body loses heat faster than it can produce it, resulting in a dangerously low body temperature. |
The 5 Ts
These factors generally involve mechanical issues, obstructions, or external substances that impede the heart and circulatory system's normal function.
| Factor | Description |
|---|---|
| Toxins | The presence of harmful substances or drugs in the body, causing poisoning or overdose. |
| Tamponade (Cardiac) | A buildup of fluid or blood in the sac surrounding the heart (pericardium), which compresses the heart and prevents it from pumping effectively. |
| Tension Pneumothorax | A life-threatening condition where air accumulates in the space between the lung and chest wall, building pressure that collapses the lung and shifts the heart and major blood vessels. |
| Thrombosis (Coronary) | The formation of a blood clot within a coronary artery, blocking blood flow to the heart muscle and causing a heart attack. |
| Thrombosis (Pulmonary) | The formation of a blood clot in the pulmonary arteries, blocking blood flow to the lungs and causing a pulmonary embolism. |
Understanding and rapidly assessing for these reversible causes is a cornerstone of advanced cardiac life support (ACLS) protocols, as highlighted in medical literature concerning cardiac arrest management, such as studies found on the National Library of Medicine.
