Which ASA classification refers to a moribund patient who is not expected to survive without an operation?

The ASA classification system, created by the American Society of Anesthesiologists, is used to assess the physical status of patients prior to undergoing anesthesia and surgery. The classification ranges from P1 to P6, with each category representing a different level of patient health.

The classification that specifically indicates a moribund patient who is not expected to survive without a surgical intervention is P5. This classification encapsulates patients whose life is in jeopardy and critical care or an urgent surgery is required for their survival. Such patients are often facing severe systemic issues that could lead to imminent death if no surgical action is taken.

In contrast, the other classifications represent different levels of health and risk. For instance, P3 refers to patients with severe systemic disease, P4 indicates patients with severe systemic disease that is a constant threat to life, and P6 pertains to declared brain-dead patients waiting for organ retrieval. Thus, P5 is the appropriate choice for identifying those who are in a dire state and need immediate surgical intervention to survive.