Final answer:
A situation is considered sterile by a PN when medical procedures at risk of contamination are carried out in a designated sterile field, free from all potential microbes and maintained through stringent aseptic technique.
Step-by-step explanation:
Based on the principle of asepsis, the PN (Practical Nurse) should consider a situation to be sterile when it involves medical procedures that carry the risk of contamination and are performed in a sterile field. This sterile field must be kept free of all vegetative microbes, endospores, and viruses, and is maintained by proper aseptic technique. Sterile items, such as surgical instruments, catheters, and intravenous fluids, are considered critical items and must be kept completely sterile as they are used inside the body, often penetrating sterile tissues or the bloodstream.
Protocols for maintaining asepsis involve using sterilized materials, proper washing techniques, application of sterilants, and procedures that prevent contamination during medical procedures. It's essential for the PN to use pre-sterilized equipment and to practice aseptic technique rigorously to prevent the transmission of infections to the patient.