ICU is critical area, monitoring plays important role . Since patient needs 24 hour monitoring nursing staff are required in additional number. Its not clear why there is 1:1,1:2, 1:3 why there is variation in ratios.
The classification of nurse patients is based on the patient’s acuity and medical needs. For critical care facilities such as the ICU, the ratio can be 1:1 for the sickest patients and 1:2 or 1:3 for patients who are acutely ill but healthy.
The licensed nurse-to-patient ratio in a critical care unit shall be 1:2 or fewer at all times