During CPR in veterinary patients, which set of reversible causes should be addressed?

• A. Ignore reversible causes.
• B. Address reversible causes (the 4 Hs and 4 Ts).
• C. Only administer drugs with no assessment.
• D. Check for breathing for 10 minutes before action.

Answer: (B)

During CPR, success depends not only on chest compressions and ventilation but also on quickly identifying and correcting problems that can cause or worsen cardiac arrest. These reversible problems are grouped as the 4 Hs and 4 Ts. The Hs include issues like not enough blood volume (hypovolemia), poor oxygenation (hypoxia), acid-base disruption from poor perfusion ( Hydrogen ion or acidosis), and electrolyte disturbances such as high potassium (hyperkalemia); hypothermia is also recognized as a complicating factor in some lists. The Ts include mechanical and toxic problems: tension pneumothorax, cardiac tamponade, thrombosis (such as a pulmonary or coronary clot), and toxins.

In practice, you perform high-quality CPR while rapidly assessing for these causes and addressing them as you go. For example, secure the airway and provide oxygen to fix hypoxia; establish IV access and give fluids or address hemorrhage to correct hypovolemia; monitor and correct acid-base and electrolyte abnormalities; manage body temperature; relieve a tension pneumothorax with decompression if present; perform pericardiocentesis for tamponade if indicated; consider thrombotic events and treat accordingly; and treat toxins as appropriate. This approach targets treatable underlying issues that can make ROSC more likely, which is why addressing the reversible causes is the best strategy during CPR.