The Acute Rehabilitation Unit (ARU), sometimes referred to as an Inpatient Rehabilitation Facility (IRF), is a specialized hospital setting. It serves as an intermediary step between a patient’s initial acute hospitalization—such as after major surgery, injury, or illness—and their eventual return home. Its purpose is to provide a highly structured and intensive environment where patients can regain functional independence before they are medically ready to be discharged to a less supervised setting. It offers specialized care focused on physical and cognitive recovery, with a level of medical oversight that is greater than what is found in a sub-acute facility.
Defining the Acute Rehabilitation Unit (ARU)
The ARU is distinct from a general medical floor or a Skilled Nursing Facility (SNF). These units are governed by specific federal regulations, such as those set by the Centers for Medicare & Medicaid Services (CMS), which dictates the intensity and type of care provided. The goal of an ARU stay is to help patients achieve significant, measurable improvements in their functional status. Unlike a SNF, the ARU is designed for patients who are already medically stable enough to tolerate a high-intensity therapy schedule. The unit operates within the hospital structure, ensuring immediate access to advanced diagnostic and medical services if an unexpected complication arises. The environment is structured to promote independence, with specialized equipment and a therapeutic atmosphere that encourages patients to practice their newly learned skills in activities of daily living.
Patient Eligibility and Admission Requirements
Admission to an ARU is based on strict medical and functional criteria. The patient must be medically stable and no longer require the constant monitoring of an Intensive Care Unit (ICU) or acute care setting. They must also require the active intervention of multiple therapy disciplines, which typically includes physical therapy and occupational therapy, with speech-language pathology often included as a third.
A patient must demonstrate the ability and willingness to participate actively in the rigorous rehabilitation program, as they must have the potential to make measurable functional gains that necessitate an inpatient stay. Common conditions treated include:
- Stroke
- Spinal cord injury
- Major trauma
- Brain injury
- Hip fracture
- Certain complex neurological disorders
The medical necessity for the admission must be documented, demonstrating that the patient’s complex needs cannot be met in a less-intensive setting, such as home health or a Skilled Nursing Facility.
The Intensive Care Model
The intensity and coordination of rehabilitation treatment define the ARU model. Patients are required to participate in an intensive therapy program, receiving a minimum of three hours of combined physical, occupational, and/or speech therapy services per day, at least five days a week. This “three-hour rule” ensures that patients are receiving a high volume of therapeutic intervention.
Care is delivered by a highly specialized, multidisciplinary team that meets regularly to coordinate the patient’s individual plan. This team is led by a physiatrist—a physician specializing in physical medicine and rehabilitation—who provides daily oversight and manages complex medical issues. The team also includes:
- Rehabilitation nurses
- Physical therapists
- Occupational therapists
- Speech-language pathologists
- Social workers or case managers
This coordinated approach ensures that all aspects of the patient’s physical, cognitive, and social needs are addressed simultaneously, under the close supervision of a physician.
Discharge Planning and Post-ARU Care
The ARU stay is short-term, with the national average length of stay around two weeks, though this varies significantly depending on the diagnosis and the patient’s progress. Discharge planning begins immediately upon admission, aiming to return the patient to their home environment with the highest level of independence possible. The interdisciplinary team works to set realistic, objective functional goals that dictate the expected length of the inpatient stay.
The social worker or case manager coordinates the patient’s transition. They arrange necessary support services, which may include home health nursing or therapy, outpatient rehabilitation, and the procurement of durable medical equipment, such as wheelchairs or hospital beds. If a patient is unable to return directly home, the team may coordinate a transfer to a lower level of care, such as a Skilled Nursing Facility, where they can continue to receive sub-acute rehabilitation at a less-intensive pace.