top of page



Acute respiratory distress syndrome. Known as ARDS

A health problem that occurs when the lungs are not able to give the blood enough oxygen. Patients who have ARDS are very ill and need medical treatment. They usually end up in the intensive care unit (ICU) on a machine that helps them breathe (ventilator). 


ARDS is caused by liquid that gets into the lungs, which should never have liquid in them. The goal of treating ARDS is to support the patient in the ICU until his or her lungs heal.

Advance directive


Instructions in writing for your family and the care team, if you are a patient. They state your wishes about medical treatment, should you become too ill to do so yourself. An advance directive is a living will or durable power of attorney. The durable power of attorney gives another person the power to make decisions about your treatment.


Laws about advance directives are different in each state, so you should write one for all states in which you spend a lot of time. An advance directive will not expire unless the person who wrote it writes a new version. Every few years, you should review and update your advance directives.

Allied health professional


A caregiver who is not a doctor or direct care registered nurse but has medical skills. An allied health professional has studied medical care, trained in it, and often earned proof of his or her efforts.  


Allied health professionals are in charge of different things. Some offer dietary tips. Some make sure medical records are up-to-date. Some lead or perform medical procedures.


Examples of allied health professionals include:

  • Emergency medical technicians

  • Pharmacists

  • Physical and occupational therapists

  • Physician assistants and nurse practitioners

  • Radiologic technologists

  • Respiratory therapists


A medicine that reduces or gets rid of pain, fever or swelling. In the intensive care unit (ICU), the care team put it on or into the patient's body to: 

  • Decrease the patient’s stress

  • Help the patient sleep through the noise and light of the ICU

  • Make the patient feel less sick, sore, stiff, forgetful or constipated


An analgesic can also reduce side effects and discomfort caused by a medical procedure.


A medicine put on or into the patient's body to cause a temporary loss of feeling. An anesthetic can also make the patient sleepy.


An anesthetic may help the patient feel more comfortable during an invasive procedure. During this kind of procedure, the skin is broken or a tube is inserted into one of the body's natural openings. This helps the care team see and treat parts inside of the patient's body, such as organs.


A condition in which the level of hemoglobin (blood) is low due to decreased production, increased destruction, or loss of red blood cells.


Medications used to treat and prevent bacterial infections.

Arterial line


Called a-line or art line


A small tube in the artery, usually placed in the wrist. The care team use this tube to check the patient’s blood pressure and take blood samples.


Some patients in the intensive care unit (ICU) need drugs that can harm their bodies over time. If so, they need their blood checked regularly. Having an a-line is more comfortable for them than getting stuck with a needle each time.



A type of blood vessel that carries oxygen-rich blood away from the heart to the rest of the body. This helps a person stay alive.

Attending physician


A medical doctor who oversees all of the patient’s care. The attending physician is also in charge of medical interns, students, and residents (those training to become doctors). He or she can change any decision made by a doctor-in-training.


Blood pressure

A force that pushes against the walls of an artery as blood moves through the artery. Having high blood pressure for a long time is dangerous. It stiffens arteries and makes them vulnerable to fat buildup, which can lead to a heart attack, a stroke or kidney failure.

Blood pressure cuff


A wide strip of fabric placed around the arm or leg. The care team automatically or manually inflate it. This helps them assess the amount of blood pressure in the patient’s veins.


Brain death


One of two kinds of death known by law—the first and most common kind occurs when the heart stops. Brain death occurs when the brain stops working. The heart of the patient who is brain dead may continue to beat, but the patient cannot breathe without machines. He or she cannot have any thoughts or feelings, including pain. When this happens, all life support is turned off. Turned-off support is not the same as withdrawn support. Support is withdrawn when the patient is alive but has chosen to die comfortably over time.



Cardiac arrest

The sudden loss of all heart function. Cardiac arrest is not the same as a heart attack, which occurs when blockage causes sudden damage to the heart. A heart attack may lead to cardiac arrest, but cardiac arrest is usually caused by:

  • Choking

  • Coronary heart disease

  • Electrocution

  • Drowning


Cardiac arrest permanently damages the brain within four to six minutes of occurring. Ninety-five percent of people who experience it do not survive. Those who do survive are likely to need critical care.


Cardiac monitor

Called heart monitor

A machine that records electrical activity of the heart. It has a screen with lines that move across it, known as tracings. Tracings appear once the care team place leads on the patient’s body. They use tracings to assess and respond to the patient’s heartbeat. Unusual beating can be a chemical or mechanical problem with the heart.


Cardiopulmonary resuscitation

Known as CPR

Medical treatment that supplies oxygen to the lungs and keeps blood flowing in the body of someone whose heart has suddenly stopped. CPR helps the caregiver prevent brain damage until he or she can better treat the patient. The caregiver who does CPR has trained in it. CPR has three steps, called circulation, airway, and breathing, or CAB.

  1. Circulation (done by compressions): The caregiver places both hands on the patient's chest and presses down about two inches. The caregiver does this one hundred times a minute.

  2. Airway: The caregiver positions the patient for breathing.

  3. Breathing: The caregiver opens the patient's mouth and slowly breathes into it two times to make the chest rise. Then the caregiver checks if the patient has a pulse. If not, the caregiver repeats all three steps until the patient has a pulse.


During CPR, the caregiver may also use a machine to restart the heart. CPR does not always work and is not the right treatment for all patients.


Case manager

A caregiver who makes sure the doctor's plan of care and post-hospital care meets the patient’s needs. These needs are based on culture, health coverage, and other factors in the patient’s life.




A thin, flexible tube inserted into the patient's body so fluids can move into and out of his or her systems. There are many types of catheters, each with a different purpose. A catheter is important in critical care because it provides the patient with:

  • Food, through the nose or stomach, when the patient is not able to eat

  • Relief, through the bladder, when the patient is not able to go to the bathroom

  • Medicine, into the vein, when the patient is feeling pain


Not being able to eat, go to the bathroom, or feel well is the result of illness or medical treatment. The care team often use peripherally inserted central catheters, or PICCs, to help the patient get better. A PICC goes through the arm into a vein until it reaches the heart.

Central venous catheter

Called CVC or central line 

A tube in the neck, chest or groin that helps the care team check and treat blood flow. It also helps them give the patient fluids, medicine or nutrients.


Sometimes, the care team put a CVC into a large vein in the arm, which is known as a peripherally inserted central catheter, or PICC. Before placing a CVC, the care team usually give the patient medicine for pain or anxiety. A CVC can stay in the patient’s body for days or weeks, as long as it shows no signs of infection.



A clergy member in the hospital who talks with patients, families and staff. The chaplain provides spiritual support and may help find a clergy member of the patient’s faith to better meet the patient’s spiritual needs. Often the chaplain plays an important role in end-of-life care.

Chest tube

A large tube inserted through the skin into the lungs. The chest tube removes air or blood that makes breathing hard to do for the patient.

Child life specialist


An expert in child development who works with ill children. The child life specialist provides play and distraction therapy. He or she often works with other experts in the pediatric intensive care unit (PICU) to improve the health and well-being of very ill children.

Chronic illness

An illness that affects the patient for a long time, sometimes for his or her entire life. Examples of this kind of illness include diabetes and emphysema. The patient may need to visit the doctor often to control symptoms of the illness. Many chronic illnesses do not have cures, so the doctor is likely to focus on improving the patient's quality of life.


Chronic obstructive pulmonary disease

Known as COPD

An illness that makes breathing hard to do. The lungs are too stiff or too floppy. Patients with COPD cough often, producing too much mucus. They may wheeze or feel tightness in their chest. Common COPDs include bronchitis and emphysema. Asthma is also a COPD. It has no cure, but the care team can treat it with medicine.


Critical care

Medical care for patients whose illness requires close, constant watch by a team of specially trained caregivers. Nearly 80% of Americans will experience this kind of illness, either as the patient or family. Most critical care takes place in an intensive care unit (ICU) or trauma center. Both places of care contain all kinds of machines, tubes, and equipment used to treat the illness. 


Critical care nurse

A highly skilled nurse who provides all aspects of care for a very ill patient. This nurse helps all of the people involved in that care talk to one another. He or she has close contact with the patient and family and can often uphold the patient's wishes. The critical care nurse becomes an important part of decision-making with the patient, the family, and the care team.


A registered nurse (RN) who is certified in critical care is known as a CCRN. CCRNs are certified by the American Association of Critical-Care Nurses.


Critical care team

A group of specially trained caregivers who work in a special area of the hospital known as the intensive care unit (ICU). They come from many professions and can help very ill patients get better. The care team often teach the patient and family strategies that improve health and well-being.


Members of the team usually include one or more of these caregivers: 

  • Intensivist

  • Critical care nurse

  • Pharmacist

  • Registered dietitian

  • Respiratory therapist

  • Physical therapist

  • Occupational therapist 

  • Chaplain


Members of the team may also include one or more of these caregivers:

  • Physician assistant or nurse practitioner

  • Child life specialist




A machine that sends an electrical charge through the chest to the heart. The care team use the defibrillator to make the patient's heart beat again or to stop it from beating in a bad pattern, which may lead to no heart beat. When the patient's heart stops beating, he or she goes into cardiac arrest. Defibrillation is the act of electrically shocking the heart.



Removing waste from the blood with special medical equipment. Dialysis helps the patient whose kidneys have failed.


Dialysis catheter

A tube in the groin or neck that connects to a machine. The tube and machine work together to clean the patient's blood when his or her kidneys are not able to do so themselves.


Donation after cardiac death

Called DCD


A process that occurs when the patient will not regain health and is removed from life support. If the patient's heart stops beating in a somewhat short timeframe, he or she can be a candidate for organ donation.


Do-not-attempt-resuscitation order

Called DNAR or DNR


Instructions on the medical chart written by the doctor but based on patient request. The order tells the care team not to attempt cardiopulmonary resuscitation (CPR) if the patient’s heart stops. It is simply a choice to say no to CPR but yes to all other appropriate medical treatments.



A caregiver who helps plan therapy that destroys cancer cells. The dosimetrist determines how best and safely to supply the amount of radiation the patient needs.



A bag of fluids, medicine, or nutrients that go into the vein to help the patient get better. The bag runs constantly on a pump.


Durable power of attorney

A legal document that gives another person the power to make decisions about the patient's medical treatment. The person only has power if the patient becomes too ill to make decisions on his or her own. What the document includes varies from state to state. It may include:

  • A sworn, signed statement from the patient that confirms who will make the decisions

  • A list of medical treatments the patient desires, such as removal of life support

  • The name and contact information of the decision-maker and two other people, should the original person not be able to make the decisions

  • The amount of time the person will have this duty



Emergency department

Called ED


A place of medical care where doctors and nurses stabilize the patient first. Then they transport the patient to the intensive care unit (ICU) or another area of the hospital for further treatment. The ED is not the same as the ICU. In the ED, caregivers determine what kind of care the patient needs and then transfer the patient to a place with that care. Sometimes, they discharge the patient home.


Emergency medical technician

Called EMT

A caregiver who responds to a medical emergency where it has happened. EMTs provide on-the-spot care for an ill patient. Then they bring the patient to the hospital for further medical treatment. Examples of care that EMTs provide include:

  • Opening airways

  • Controlling bleeding

  • Assisting with childbirth

End-of-life care


The medical care that a very ill patient receives when he or she will not regain health. Many intensive care units (ICUs) have rules in place for this care. The goal of end-of-life care is to make sure the patient dies as dignified and pain-free as possible. End-of-life care can take place in the hospital, a home or the hospice unit.

Endotracheal tube

Called ETT


A tube connected to a machine that helps the patient breathe. The tube is inserted through the mouth or nose. Oxygen moves from the machine, through the tube, into the lungs, and throughout the body.


Foley catheter

Called urinary catheter


A tube inserted into the bladder and kept in place by a balloon that drains the bladder. The urinary catheter helps the care team measure how much urine the patient is producing. It helps them determine if that amount is normal or if the patient’s kidneys are not working in the way they should.



Not being able to perform a function that involves the body, thoughts, feelings or mind. Examples of these functions include:

  • Eating

  • Walking

  • Caring for oneself

  • Making decisions

  • Being aware of one's surroundings


Informed consent

Permission you give to the doctor to treat you, if you are the patient. Before you give permission, the doctor should explain the risks and benefits of the treatment to you. By law, doctors must have informed consent before starting any treatment. If you are too ill to consent, consent will likely be from someone you have chosen ahead of time as your decision-maker.


Inpatient care

Medical treatment in a hospital. To receive inpatient care, the patient stays in the hospital for at least one day, but often more. Critical care is almost always inpatient care.


Intensive care unit

Called ICU


An area in the hospital with special equipment and staff, who are known as the critical care team. The care team check on and treat very ill patients all day and all night. Patients come to the ICU from the emergency department or another area of the hospital—usually after surgery. They may also come from a place of care outside of the hospital.


There are many kinds of ICUs, including: 

  • Burn or trauma unit

  • Coronary care unit, or CCU

  • Medical intensive care unit, or MICU

  • Neonatal intensive care unit, or NICU

  • Neurosurgery intensive care unit, or NSICU

  • Pediatric intensive care unit, or PICU

  • Surgical intensive care unit, or SICU


A medical doctor who has studied, trained, and tested in caring for very ill patients. The intensivist is often an expert in one of these areas:

  • Surgery

  • Internal medicine

  • Pediatrics

  • Anesthesiology

Intra-aortic balloon pump

A machine that helps a weak heart pump blood throughout the body. The machine has a tube that goes into the body's main artery, and the tube has a balloon that inflates and deflates to match the natural beating of the heart.


Intracranial pressure catheter

A small tube placed into the brain. It helps the care team keep an eye on swelling in the brain and, if necessary, drain excess fluid from around the brain.



In a vein.


Intravenous feeding

Called intravenous catheter or IV.

Giving the patient nutrients in the form of liquid through a tube when the patient is not able to eat or his or her digestive system needs to rest. The tube goes into a vein in the arm or neck. Keywords: intravenous, feeding, catheter, IV


Intravenous therapy


Giving the patient fluids, medicine, or nutrients through a tube in a vein. Some patients need this therapy once, and other patients need it nonstop. Intravenous therapy can help the patient:

  • Regain lost body fluids or moisture

  • Eat

  • Receive medicine that controls blood pressure or heart rate

  • Feel numb during an unpleasant medical treatment



it, such as breathing. The patient has no control.

Understanding the terminology used in the intensive care unit ("ICU") is important for patients, caregivers and family members.

This glossary covers most of the words that you may here medical professionals use in the ICU.

Click on any letter to find the glossary term that you are looking for

N, O & P
H, I, J & K
L & M
Q, R & S
T, U & V
W, X, Y & Z
C & D
E, F & G

Glossary of Hospital ICU Terms.

ICU Terminology


Laboratory technician

A caregiver who obtains and tests samples from the b