Intensive care medicine, also called critical care medicine, is a medical specialty
that deals with seriously or critically ill patients who have, are at risk of, or are recovering from conditions that may be life-threatening.
It includes providing
Life support comprises the treatments and techniques performed in an emergency in order to support life after the failure of one or more vital organs. Healthcare providers and emergency medical technicians are generally certified to perform basi ...
, invasive monitoring
End-of-life care (EoLC) refers to health care provided in the time leading up to a person's death. End-of-life care can be provided in the hours, days, or months before a person dies and encompasses care and support for a person's mental and emotio ...
Doctors in this specialty are often called intensive care physicians, critical care physicians or intensivists.
Intensive care relies on multidisciplinary teams composed of many different health professionals. Such teams often include doctors, nurses,
Physical therapy (PT), also known as physiotherapy, is one of the allied health professions. It is provided by physical therapists who promote, maintain, or restore health through physical examination, diagnosis, management, prognosis, patient ...
, respiratory therapist
A pharmacist, also known as a chemist ( Commonwealth English) or a druggist (North American and, archaically, Commonwealth English), is a healthcare professional who prepares, controls and distributes medicines and provides advice and instruc ...
s, among others. They usually work together in intensive care unit
s (ICUs) within a hospital.
Patients are admitted to the intensive care unit if their medical needs are greater than what the general hospital ward can provide. Indications for the ICU include blood pressure support for cardiovascular instability (
Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high blo ...
Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure (the top number) and the diast ...
Sepsis, formerly known as septicemia (septicaemia in British English) or blood poisoning, is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage is follo ...
, post-cardiac arrest syndrome
or certain cardiac arrhythmias
Other ICU needs include airway or
A ventilator is a piece of medical technology that provides mechanical ventilation by moving breathable air into and out of the lungs, to deliver breaths to a patient who is physically unable to breathe, or breathing insufficiently. Ventilators ...
support due to respiratory compromise
. The cumulative effects of
multiple organ failure
Multiple organ dysfunction syndrome (MODS) is altered organ function in an acutely ill patient requiring medical intervention to achieve homeostasis.
Although Irwin and Rippe cautioned in 2005 that the use of "multiple organ failure" or "multisy ...
, more commonly referred to as multiple organ dysfunction syndrome
, also requires advanced care.
Patients may also be admitted to the ICU for close monitoring or intensive needs following a major surgery.
There are two common ICU structures: closed and open.
In a closed unit, the intensivist takes on the primary role for all patients in the unit.
In an open ICU, the primary physician, who may or may not be an intensivist, can differ for each patient.
There is increasingly strong evidence that closed units provide better patient outcomes. Patient management in intensive care differs between countries. Open units are the most common structure in the United States, but closed units are often found at large academic centers.
Intermediate structures that fall between open and closed units also exist.
Types of intensive care units
Intensive care is usually provided in a specialized unit of a
A hospital is a health care institution providing patient treatment with specialized health science and auxiliary healthcare staff and medical equipment. The best-known type of hospital is the general hospital, which typically has an emergency ...
called the intensive care unit
(ICU) or critical care unit (CCU). Many hospitals also have designated intensive care areas for certain specialities of medicine.
The naming is not rigidly standardized, and types of units are dictated by the needs and available resources of each hospital. These include:
* coronary intensive care unit (CCU or sometimes CICU) for heart disease
* medical intensive care unit (MICU)
* surgical intensive care unit (SICU)
* pediatric intensive care unit (PICU)
* neuroscience critical care unit (NCCU)
* overnight intensive-recovery (OIR)
/trauma intensive-care unit (STICU)
* neonatal intensive care unit (NICU)
* ICU in the emergency department (E-ICU)
Medical studies suggest a relation between ICU volume and quality of care for mechanically ventilated patients. After adjustment for severity of illness, demographic variables, and characteristics of the ICUs (including staffing by intensivist
s), higher ICU volume was significantly associated with lower ICU and hospital mortality rates. For example, adjusted ICU mortality (for a patient at average predicted risk for ICU death) was 21.2% in hospitals with 87 to 150 mechanically ventilated patients annually, and 14.5% in hospitals with 401 to 617 mechanically ventilated patients annually. Hospitals with intermediate numbers of patients had outcomes between these extremes. ICU delirium
, formerly and inaccurately referred to as ICU psychosis, is a syndrome common in intensive care and cardiac units where patients who are in unfamiliar, monotonous surroundings develop symptoms of delirium (Maxmen & Ward, 1995). This may include interpreting machine noises as human voices, seeing walls quiver, or hallucinating that someone is tapping them on the shoulder.
[Nolen-Hoeksema, Susan. "Neurodevelopmental and Neurocognitive Disorders." ''(Ab)normal Psychology''. Sixth ed. New York City: McGraw-Hill Education, 2014. 314. Print.]
There exists systematic reviews in which interventions of sleep promotion related outcomes in the ICU have proven impactful in the overall health of patients in the ICU.
The English nurse
Florence Nightingale (; 12 May 1820 – 13 August 1910) was an English social reformer, statistician and the founder of modern nursing. Nightingale came to prominence while serving as a manager and trainer of nurses during the Crimean War, ...
pioneered efforts to use a separate hospital area for critically injured patients. During the
The Crimean War, , was fought from October 1853 to February 1856 between Russia and an ultimately victorious alliance of the Ottoman Empire, France, the United Kingdom and Piedmont-Sardinia.
Geopolitical causes of the war included the d ...
in the 1850s, she introduced the practice of moving the sickest patients to the beds directly opposite the nursing station on each ward so that they could be monitored more closely.
In 1923, the American
Neurosurgery or neurological surgery, known in common parlance as brain surgery, is the medical specialty concerned with the surgical treatment of disorders which affect any portion of the nervous system including the brain, spinal cord and peri ... Walter Dandy
created a three-bed unit at the Johns Hopkins Hospital
. In these units, specially trained nurses cared for critically ill postoperative neurosurgical patients.
The Danish ] anaesthesiologist
Anesthesiology, anaesthesiology, or anaesthesia is the medical specialty concerned with the total perioperative care of patients before, during and after surgery. It encompasses anesthesia, intensive care medicine, critical emergency medicine, ... Bjørn Aage Ibsen became involved in the 1952 poliomyelitis
Poliomyelitis, commonly shortened to polio, is an infectious disease caused by the poliovirus. Approximately 70% of cases are asymptomatic; mild symptoms which can occur include sore throat and fever; in a proportion of cases more severe sym ... epidemic in Copenhagen
Copenhagen ( or .; da, København ) is the capital and most populous city of Denmark, with a proper population of around 815.000 in the last quarter of 2022; and some 1.370,000 in the urban area; and the wider Copenhagen metropolitan ar ..., where 2722 patients developed the illness in a six-month period, with 316 of those developing some form of respiratory or airway paralysis. Some of these patients had been treated using the few available negative pressure ventilators, but these devices (while helpful) were limited in number and did not protect the patient's lungs from aspiration of secretions. Ibsen changed the management directly by instituting long-term positive pressure ventilation using tracheal intubation
Tracheal intubation, usually simply referred to as intubation, is the placement of a flexible plastic tube into the trachea (windpipe) to maintain an open airway or to serve as a conduit through which to administer certain drugs. It is frequently ..., and he enlisted 200 medical students to manually pump oxygen and air into the patients' lungs round the clock. At this time, Carl-Gunnar Engström had developed one of the first artificial positive-pressure volume-controlled ventilators, which eventually replaced the medical students. With the change in care, mortality during the epidemic declined from 90% to around 25%. Patients were managed in three special 35-bed areas, which aided charting medications and other management.
In 1953, Ibsen set up what became the world's first intensive care unit in a converted student nurse classroom in Copenhagen Municipal Hospital
Copenhagen Municipal Hospital ( Danish: Københavns Kommunehospital) was a hospital that existed from 1863 until 1999 in Copenhagen, Denmark. Its buildings, located on Øster Farimagsgade, opposite Copenhagen Botanical Garden, now form part of t .... He provided one of the first accounts of the management of tetanus
Tetanus, also known as lockjaw, is a bacterial infection caused by ''Clostridium tetani'', and is characterized by muscle spasms. In the most common type, the spasms begin in the jaw and then progress to the rest of the body. Each spasm usually ... using neuromuscular-blocking drugs and controlled ventilation. The following year, Ibsen was elected head of the department of anaesthesiology at that institution. He jointly authored the first known account of intensive care management principles in the journal ''Nordisk Medicin'', with Tone Dahl Kvittingen from Norway.
For a time in the early 1960s, it was not clear that specialized intensive care units were needed, so intensive care resources were brought to the room of the patient that needed the additional monitoring, care, and resources. It became rapidly evident, however, that a fixed location where intensive care resources and dedicated personnel were available provided better care than ''ad hoc'' provision of intensive care services spread throughout a hospital. In 1962, in the University of Pittsburgh, the first critical care residency was established in the United States. In 1970, the Society of Critical Care Medicine was formed.
Monitoring refers to various tools and technologies used to obtain information about a patient's condition. These can include tests to evaluate
Hemodynamics or haemodynamics are the dynamics of blood flow. The circulatory system is controlled by homeostatic mechanisms of autoregulation, just as hydraulic circuits are controlled by control systems. The hemodynamic response continuously m ... and gas exchange in the body, or to assess the function of organs such as the heart and lungs. Broadly, there are two common types of monitoring in the ICU: noninvasive and invasive.
Noninvasive monitoring does not require puncturing the skin and usually does not cause pain. These tools are more inexpensive, easier to perform, and faster to result.
* Vital signs which includes heart rate, blood pressure, breathing rate, body temperature
* Echocardiogram to evaluate the function and structure of the heart
* Electroencephalography (EEG) to assess electrical activity of the brain
* Electrocardiogram to detect abnormal heart rhythms, electrolyte disturbances, and coronary blood flow
* Pulse oximetry for monitoring oxygen levels in the blood
* Thoracic electric bioimpedance (TEB) cardiography to monitor fluid status and heart function
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies fr ... to evaluate internal structures including the heart, lungs, gallbladder, liver, kidneys, bladder, and blood vessels
Invasive monitoring generally provides more accurate measurements, but these tests may require blood draws, puncturing the skin, and can be painful or uncomfortable.
* Arterial line to directly monitor blood pressure and obtain arterial blood gas measurements
* Blood draws or venipucture to monitor various blood components as well as administer therapeutic treatments
* Intracranial pressure monitoring to assess pressures inside the skull and on the brain
*Intravesicular manometry (bladder pressure) measurements to assess for intra-abdominal pressure
* Central line and peripherally inserted central catheter (PICC) lines for drug infusions, fluids or total parenteral nutrition
Parenteral nutrition (PN) is the feeding of nutritional products to a person intravenously, bypassing the usual process of eating and digestion. The products are made by pharmaceutical compounding companies. The person receives a nutritional mi ...
Bronchoscopy is an endoscopic technique of visualizing the inside of the airways for diagnostic and therapeutic purposes. An instrument (bronchoscope) is inserted into the airways, usually through the nose or mouth, or occasionally through a tra ... to look at lungs and airways and sample fluid within the lungs
* Pulmonary artery catheter to monitor the function of the heart, blood volume, and tissue oxygenation
Procedures and treatments
Intensive care usually takes a system-by-system approach to treatment.
In alphabetical order, the nine key systems considered in the intensive care setting are: cardiovascular system
The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, tha ..., central nervous system
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all ..., endocrine system
The endocrine system is a messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs. In vertebrates, the hypothalamus is the neur ..., gastro-intestinal tract (and nutritional condition), hematology
Hematology ( always spelled haematology in British English) is the branch of medicine concerned with the study of the cause, prognosis, treatment, and prevention of diseases related to blood. It involves treating diseases that affect the produc ..., integumentary system
The integumentary system is the set of organs forming the outermost layer of an animal's body. It comprises the skin and its appendages, which act as a physical barrier between the external environment and the internal environment that it serves ..., microbiology
Microbiology () is the scientific study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). Microbiology encompasses numerous sub-disciplines including virology, bacteriology, pr ... (including sepsis status), renal (and metabolic), and respiratory system
The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies gre .... As such, the nine key systems are each considered on an observation–intervention–impression basis to produce a daily plan.
* Temporary cardiac pacing catheters for atrial, ventricular, or dual-chamber pacing
Intra-aortic balloon pump
The intra-aortic balloon pump (IABP) is a mechanical device that increases myocardial oxygen perfusion and indirectly increases cardiac output through afterload reduction. It consists of a cylindrical polyurethane balloon that sits in the aorta ...ing to stabilize patients with cardiogenic shock
* Ventricular assist device to aid in the function of the left ventricle, commonly in patients with advanced heart failure
Eating (also known as consuming) is the ingestion of food, typically to provide a heterotrophic organism with energy and to allow for growth. Animals and other heterotrophs must eat in order to survive — carnivores eat other animals, herb ... for artificial nutrition
* Nasogastric intubation can be used to deliver artificial nutrition, but can also be used to remove stomach and intestinal contents
* Peritoneal aspiration and lavage to sample fluid in the abdominal cavity
* Hemofiltration for acute kidney injury
Mechanical ventilation, assisted ventilation or intermittent mandatory ventilation (IMV), is the medical term for using a machine called a ventilator to fully or partially provide artificial ventilation. Mechanical ventilation helps move air ... to assist breathing and oxygenation through an endotracheal tube, tracheotomy (invasive) or mask, helmet (non-invasive).
* Thoracentesis or tube thoracostomy to remove fluid or air in the pleural cavity
A wide array of
A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via inhalati ... including but not limited to: inotropes, sedatives
A sedative or tranquilliser is a substance that induces sedation by reducing irritability or excitement. They are CNS depressants and interact with brain activity causing its deceleration. Various kinds of sedatives can be distinguished, but t ..., broad spectrum antibiotics
An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ... and analgesics
An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It i ....
Physiotherapy and mobilization
Interventions such as early mobilization or exercises to improve muscle strength are sometimes suggested.
Common complications in the ICU
Intensive care units are associated with increased risk of various complications that may lengthen a patient's hospitalization.
Common complications in the ICU include:
* Acute renal failure
* Catheter-associated bloodstream infection
* Catheter-associated urinary tract infection
Delirium (also known as acute confusional state) is an organically caused decline from a previous baseline of mental function that develops over a short period of time, typically hours to days. Delirium is a syndrome encompassing disturbances ...
* Gastrointestinal bleeding
Gastrointestinal bleeding (GI bleed), also called gastrointestinal hemorrhage (GIB), is all forms of bleeding in the gastrointestinal tract, from the mouth to the rectum. When there is significant blood loss over a short time, symptoms may include ...
* Pressure ulcer
* Venous thromboembolism
* Ventilator-associated pneumonia
Ventilator-associated pneumonia (VAP) is a type of lung infection that occurs in people who are on mechanical ventilation breathing machines in hospitals. As such, VAP typically affects critically ill persons that are in an intensive care unit (I ...
* Ventilator-induced barotrauma
Death is the irreversible cessation of all biological functions that sustain an organism. For organisms with a brain, death can also be defined as the irreversible cessation of functioning of the whole brain, including brainstem, and brain ...
ICU care requires more specialized patient care; this need has led to the use of a multidisciplinary team to provide care for patients.
Staffing between Intensive care units by country, hospital, unit, or institution.
Critical care medicine is an increasingly important medical specialty.
A physician (American English), medical practitioner ( Commonwealth English), medical doctor, or simply doctor, is a health professional who practices medicine, which is concerned with promoting, maintaining or restoring health through t ...s with training in critical care medicine are referred to as intensivists.
Most medical research has demonstrated that ICU care provided by intensivists produces better outcomes and more cost-effective care. This has led the Leapfrog Group
A Patient Safety Organization (PSO) is a group, institution, or association that improves medical care by reducing medical errors. Common functions of patient safety organizations are data collection and analysis, reporting, education, funding ... to make a primary recommendation that all ICU patients be managed or co-managed by a dedicated intensivist who is exclusively responsible for patients in one ICU.
In Australia, the training in intensive care medicine is through College of Intensive Care Medicine.
In the United Kingdom
In the UK, doctors can only enter intensive care medicine training after completing two foundation years and core training in either emergency medicine, anaesthetics, acute medicine or core medicine. Most trainees dual train with one of these specialties; however, it has recently become possible to train purely in intensive care medicine. It has also possible to train in sub-specialties of intensive care medicine including
pre-hospital emergency medicine
Pre-hospital emergency medicine (abbreviated PHEM), also referred to as pre-hospital care, immediate care, or emergency medical services medicine (abbreviated EMS medicine), is a medical subspecialty which focuses on caring for seriously ill or ....
In the United States
In the United States, the specialty requires additional fellowship training for physicians having completed their primary residency training in internal medicine,
Pediatrics ( also spelled ''paediatrics'' or ''pædiatrics'') is the branch of medicine that involves the medical care of infants, children, adolescents, and young adults. In the United Kingdom, paediatrics covers many of their youth until the ..., anesthesiology
Anesthesiology, anaesthesiology, or anaesthesia is the medical specialty concerned with the total perioperative care of patients before, during and after surgery. It encompasses anesthesia, intensive care medicine, critical emergency medicine, ..., surgery
Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pat ... or emergency medicine
Emergency medicine is the medical speciality concerned with the care of illnesses or injuries requiring immediate medical attention. Emergency physicians (often called “ER doctors” in the United States) continuously learn to care for unsch .... US board certification in critical care medicine is available through all five specialty boards. Intensivists with a primary training in internal medicine sometimes pursue combined fellowship training in another subspecialty such as pulmonary medicine, cardiology, infectious disease, or nephrology. The American Society of Critical Care Medicine is a well-established multi professional society for practitioners working in the ICU including nurses, respiratory therapists, and physicians.
Intensive care physicians have some of the highest percentages of physician burnout among all medical specialties, at 48 percent.
Nurses that work in the critical care setting are typically registered nurses.
Nursing is a profession within the health care sector focused on the care of individuals, families, and communities so they may attain, maintain, or recover optimal health and quality of life. Nurses may be differentiated from other health c ...s may pursue additional education and training in critical care medicine leading to certification as a CCRN by the American Association of Critical Care Nurses a standard that was begun in 1975. These certifications became more specialized to the patient population in 1997 by the American Association of Critical care Nurses, to include pediatrics, neonatal and adult.
Nurse practitioners and physician assistants
A nurse practitioner (NP) is an advanced practice registered nurse and a type of mid-level practitioner. NPs are trained to assess patient needs, order and interpret diagnostic and laboratory tests, diagnose disease, formulate and prescribe ...s and physician assistant
A physician assistant or physician associate (PA) is a type of mid-level health care provider. In North America PAs may diagnose illnesses, develop and manage treatment plans, prescribe medications, and may serve as a principal healthcare prov ...s are other types of non-physician providers that care for patients in ICUs. These providers have fewer years of in-school training, typically receive further clinical on the job education, and work as part of the team under the supervision of physicians.
Critical care pharmacists work with the medical team in many aspects, but some include, monitoring serum concentrations of medication, past medication use, current medication use, and medication allergies.
Their typically round with the team, but it may differ by institution. Some pharmacist after attaining their doctorate or pharmacy may pursue additional training in a postgraduate residency and become certified as critical care pharmacists. Pharmacists help manage all aspects of drug therapy and may pursue additional credentialing in critical care medicine as BCCCP by the Board of Pharmaceutical Specialties. Many critical care pharmacists are a part of the multi-professional Society of Critical Care Medicine. Inclusion of pharmacist decreases drug reactions and poor outcomes for patients.
Nutrition in intensive care units presents unique challenges due to changes in patient metabolism and physiology while critically ill. Critical care nutrition is rapidly becoming a subspecialty for dieticians who can pursue additional training and achieve certification in enteral and parenteral nutrition through the American Society for Parenteral and Enteral Nutrition (ASPEN).
Respiratory therapists often work in intensive care units to monitor how well a patient is breathing.
Respiratory therapists may pursue additional education and training leading to credentialing in adult critical care (ACCS) and neonatal and pediatric (NPS) specialties. These therapists have been trained to monitor a patient's breathing, provide treatments to help their breathing and evaluate for respiratory improvement. They may be involved in emergency care like managing an airway, humidification of oxygen, administering diagnostic test, invasive or non-invasive mechanical ventilation management, training patients weaning the ventilator, aerosol therapy, inhaled Nitric oxide therapy, artery blood gas analysis and providing physiotherapy.
Ethical and medicolegal issues
In general, it is the most expensive, technologically advanced and resource-intensive area of medical care. In the
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ..., estimates of the 2000 expenditure for critical care medicine ranged from US$19–55 billion. During that year, critical care medicine accounted for 0.56% of GDP
Gross domestic product (GDP) is a monetary measure of the market value of all the final goods and services produced and sold (not resold) in a specific time period by countries. Due to its complex and subjective nature this measure is ofte ..., 4.2% of national health expenditure and about 13% of hospital costs.
In 2011, hospital stays with ICU services accounted for just over one-quarter of all discharges (29.9%) but nearly one-half of aggregate total hospital charges (47.5%) in the United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie .... The mean hospital charge was 2.5 times higher for discharges with ICU services than for those without.
Mechanical ventilation, assisted ventilation or intermittent mandatory ventilation (IMV), is the medical term for using a machine called a ventilator to fully or partially provide artificial ventilation. Mechanical ventilation helps move air ...
* Extracorporeal membrane oxygenation
Telemetry is the in situ collection of measurements or other data at remote points and their automatic transmission to receiving equipment ( telecommunication) for monitoring. The word is derived from the Greek roots ''tele'', "remote", and ...
* Chronic critical illness
* Critical care nursing
Intensive Care Medicine by Irwin and Rippe
Civetta, Taylor, and Kirby's Critical Care
The ICU Book by Marino
''Procedures and Techniques in Intensive Care Medicine by Irwin and Rippe''
Brazilian Society of Intensive Care - SOBRATI
Society of Critical Care Medicine
College of Intensive Care Medicine - Australia and New Zealand
Australia and New Zealand Intensive Care Society
Society of Critical Care Medicine
Veterinary Emergency And Critical Care Society
ESICM: European Society of Intensive Care Medicine
ESPNIC: The society for paediatric and neonatal intensive care healthcare professionals in Europe
UK Intensive Care Society
Scottish Intensive Care Society
Hong Kong Society of Critical Care Medicine
Chinese Society of Critical Care Medicine
Taiwan Society of Critical Care Medicine
From Iron Lungs to Intensive Care
Royal Institution debate, February 2012