The word "intensive" means something that requires a lot of effort, focus, or time. It describes a task or activity that is done with great concentration or in a concentrated manner. Full definition
Many dogs require several days of intensive care in order to recover. (dogster.com)
Depending on the severity of the patient's symptoms and blood work abnormalities, they may require multiple days of intensive care with aggressive medical management. (gcvs.com)
Family members thought the program should be available to all families and during all phases of hospitalization, including in intensive care units. (sciencedaily.com)