Final answer:
Post-cardiac arrest, the recommended duration for targeted temperature management is at least 24 hours (option a) to reduce heart damage by slowing the metabolic rate.
Step-by-step explanation:
During post-cardiac arrest, the recommended duration of targeted temperature management (TTM) after reaching the correct temperature range is at least 24 hours. This practice is employed in settings such as the emergency department to reduce further damage to the heart after a patient has suffered a cardiac arrest. By inducing a coma and cooling the patient's body temperature to approximately 91 degrees Fahrenheit, the metabolic rate is slowed, and the patient's organs require less blood to function, effectively reducing the heart's workload.
Additionally, controlled hypothermia is used in other clinical scenarios such as open-heart surgery where it helps reduce metabolic needs and the risk of damage.