Patients requiring intensive care are usually at higher risk than other patients of becoming colonized or infected with organisms of special clinical or epidemiologic significance. Three reasons are that contacts between these patients and personnel are frequent, the patients are clustered in a confined area, and many of them are unusually susceptible to infection. Moreover, critically ill patients are more likely to have multiple invasive procedures performed on them. Because there is ample opportunity for cross-infection in the Intensive Care Unit (ICU), infection control precautions must be done scrupulously. Frequent in-service training and close supervision to ensure adequate application of infection control and isolation precautions are particularly important for ICU personnel. (See Guideline for Hospital Environmental Control: Intensive Care Units.)

Most ICUs pose special problems for applying isolation precautions, hence some modifications that will neither compromise patient care nor increase the risk of infection to other patients or personnel may be necessary. The isolation precaution that will most often have to be modified is the use of a private room. Ideally, private rooms should be available in ICUs, but some ICUs do not have them or do not use them for patients who are critically ill if frequent and easy accessibility by personnel is crucial. When a private room is not available or is not desirable because of the patient's critical condition, and if airborne transmission is not likely, an isolation area can be defined within the ICU by curtains, partitions, or an area marked off on the floor with tape. Instructional cards can be posted to inform personnel and visitors about the isolation precautions in use.