Cardiac arrest is caused by the absence of appropriate mechanical activity of the heart, resulting in a cessation of circulation and inevitable death if resuscitation is not initiated. Although it is mostly of cardiogenic etiology, cardiac arrest can also be noncardiogenic. Noncardiogenic causes are mostly reversible, meaning that timely recognition and treatment can lead to the return of spontaneous circulation and cessation of cardiac arrest. The European Resuscitation Council guidelines in their ALS (Advanced Life Support) algorithm recommend the use of the mnemonic "4H and 4T" to recognize noncardiogenic causes, where the four H's stand for hypoxia, hypovolemia, hypo- and hyperkalemia, and hypo- and hyperthermia. The four T's are tamponade, tension pneumothorax, thrombosis, i.e., pulmonary embolism and coronary artery thrombosis, and toxins. Hypoxia is the most common cause of cardiac arrest in the pediatric population. It mostly occurs due to asphyxia and is preceded by a pre-arrest period of progressive worsening of cardiopulmonary function. Cardiac arrest due to hypovolemia is mostly seen in trauma patients due to significant blood loss. The key to treatment is stopping the bleeding and quickly replacing volume with solutions and blood products. Hyperkalemia and hypokalemia are the most common electrolyte disturbances causing cardiac arrest and are frequent in patients with impaired renal function. Hypothermia is not as common, but patients with cardiac arrest due to hypothermia have very good survival and neurological outcomes since hypothermia has a protective effect on the brain. Hyperthermia is also uncommon, but it is important for anesthesiologists to pay attention to the patient's susceptibility to malignant hyperthermia, a hypermetabolic reaction of skeletal muscles to inhalation anesthetics and succinylcholine. Cardiac tamponade and tension pneumothorax mostly occur during injuries and traumas, causing cardiac arrest through mechanical obstruction of blood flow, so standard resuscitation procedures without treating these causes are often futile. Pulmonary embolism and coronary artery thrombosis are the most common causes of cardiac arrest and require urgent transport of the patient to a hospital where treatment is possible. Cardiac arrest caused by toxins occurs due to direct toxic effects on the heart or electrolyte disturbances and is most commonly caused by overdose of opioids, benzodiazepines in combination with alcohol, and tricyclic antidepressants.