In general, ICU is the most expensive, technologically-advanced and resource-intensive area of medical care. Intensive care is usually only offered to those whose condition is potentially reversible and who have a good chance of surviving with intensive care support. A prime requisite for admission to an Intensive Care Unit is that the underlying condition can be overcome.

The NICU is a unit of a hospital specializing in the care of ill or premature newborn infants. NICUs have greatly increased the survival of very low birth weight and extremely premature infants.

The PICU is an area within a hospital specializing in the care of critically ill infants, children, and teenagers. The ratio of professionals to patients is generally higher than in other areas of the hospital, reflecting the acuity of PICU patients and the risk of life-threatening complications. As with NICU, complex technology and equipment is often in use, particularly mechanical ventilators and patient monitoring systems. Consequently, PICUs have a larger operating budget than many other departments within the hospital.