Final answer:
The assessment phase is when a nurse establishes a comprehensive baseline of data for a patient, including collecting health history and confirming the patient's identity and the sterility of equipment.
Step-by-step explanation:
The phase of the nursing process that requires the nurse to establish a comprehensive baseline of data concerning a particular patient is the assessment phase. During this initial step, the nurse collects a complete health history and performs a physical examination. The data collected includes, but is not limited to, reviewing patient records, confirming patient's identity, discussing past and current medical conditions, checking vital signs, and ensuring that all equipment and instruments are sterile and functional. This thorough inspection supports the creation of an appropriate care plan by identifying the patient's needs and any potential risks or complications that may arise from the treatment or procedure.