Intensive care medicine

Overview
Intensive Care Medicine or critical care medicine is a branch of medicine concerned with the provision of life support or organ support systems in patients who are critically ill and who usually require intensive monitoring.

Patients requiring intensive care usually require support for hemodynamic instability (hypertension/hypotension), airway or respiratory compromise (such as ventilator support), acute renal failure, potentially lethal cardiac dysrhythmias, and frequently the cumulative affects of multiple organ system failure. Patients admitted to the intensive care unit not requiring support for the above are usually admitted for intensive/invasive monitoring, such as the crucial hours after major surgery when deemed too unstable to transfer to a less intensively monitored unit.

Ideally, 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. Since the critically ill are so close to dying, the outcome of this intervention is difficult to predict. Many patients, therefore, die in the Intensive Care Unit. A prime requisite for admission to an Intensive Care Unit is that the underlying condition can be overcome. Therefore, treatment is merely meant to win time in which the acute affliction can be resolved.

Medical studies suggest a relation between intensive care unit (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 intensivists), 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.

It is generally the most expensive, high technology and resource intensive area of medical care. In the United States estimates of the 2000 expenditure for critical care medicine ranged from US$15-55 billion accounting for about 0.5% of GDP and about 13% of national health care expenditure (Halpern, 2004).

Organ systems
Intensive care usually takes a system by system approach to treatment, rather than the SOAP (subjective, objective, analysis, plan) approach of high dependency care. The nine key systems (see below) are each considered on an observation-intervention-impression basis to produce a daily plan. As well as the key systems, intensive care treatment also raises other issues including psychological health, pressure points, mobilisation and physiotherapy, and secondary infections.

The nine key IC systems are (alphabetically): cardiovascular system, central nervous system, endocrine system, gastro-intestinal tract (and nutritional condition), hematology, microbiology (including sepsis status), peripheries (and skin), renal (and metabolic), respiratory system.

The provision of intensive care is generally administered in a specialized unit of a hospital called the Intensive Care Unit (ICU) or Critical Care Unit (CCU). Many hospitals also have designated intensive care areas for certain specialities of medicine, such as the Coronary Care Unit (CCU) 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), Shock/Trauma Intensive Care Unit (STICU), Neonatal Intensive Care Unit (NICU), and other units as dictated by the needs and available resources of each hospital. The naming is not rigidly standardized. For a time in the early 1960s, it was not clear that specialized intensive care units were needed, so intensive care resources (see below) were brought to the room of the patient who needed the additional monitoring, care, and resources. It became rapidly evident, though, that a fixed location where intensive care resources and personnel were available provided better care than ad hoc provision of intensive care services spread throughout a hospital.

Equipment and systems
Common equipment in an intensive care unit (ICU) includes mechanical ventilation to assist breathing through an endotracheal tube or a tracheotomy; hemofiltration equipment for acute renal failure; monitoring equipment; intravenous lines for drug infusions fluids or total parenteral nutrition, nasogastric tubes, suction pumps, drains and catheters; and a wide array of drugs including inotropes, sedatives, broad spectrum antibiotics and analgesics.

Physicians, Veterinary Criticalists and Intensivists
Critical care medicine is a relatively new but increasingly important medical specialty. Physicians who have training in critical care medicine are referred to as intensivists. The specialty requires additional fellowship training for physicians who complete their primary residency training in internal medicine, anesthesiology, or surgery. Board certification in critical care medicine is available through all three 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 Society of Critical Care Medicine is a well established multiprofessional society for pracitioners who work in the ICU, including intensivists. Medical research has repeatedly demonstrated that ICU care provided by intensivists produces better outcomes and more cost effective care. This has led the Leapfrog Group 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. Unfortunately there is a critical shortage of intensivists in the United States and most hospitals lack this critical physician team member.

In veterinary medicine, critical care medicine is recognized as a specialty and is closely allied with emergency medicine. Board-certified veterinary critical care specialists are known as criticalists, and generally are employed in referral institutions or universities.

Patient management in intensive care differs significantly between countries. In Australia, where Intensive Care Medicine is a well established speciality, ICUs are described as 'closed'. In a closed unit the intensive care specialist takes on the senior role where the patient's primary doctor now acts as a consultant. Other countries have open Intensive Care Units, where the primary doctor chooses to admit and generally makes the management decisions. There is increasingly strong evidence that 'closed' Intensive Care Units staffed by Intensivists provide better outcomes for patients.

Florence Nightingale era
The ICU's roots can be traced back to the Monitoring Unit of critical patients through nurse Florence Nightingale. In 1854 the Crimean War, in which Britain, France and Turkey declared war on Russia, began. Because of the lack of critical care and the high rate of infection, there was a high mortality rate of hospitalised soldiers, reaching as high as 40% of the deaths recorded during the war. Florence and 38 other volunteers had to leave for the Fields of Scurati, and took their "critical care protocol" with them. Upon arriving, and practicing, the mortality rate fell to 2%. Nightingale contracted typhoid, and returned in 1856 from the war. A School of Nursing was formed in 1859 in England dedicated to her. The School was recognized for its professional value and technical calibre, receiving prizes throughout the British government. The School of Nursing was established in Saint Thomas Hospital, as a one year course, and was given to doctors. It utilised theoretical and practical lessons, as opposed to purely academic lessons. Her work, and the school, paved the way for Intensive Care Medicine.

Dandy era
Walter Edward Dandy was born in Sedalia, Missouri. He received his BA in 1907 through the University of Missouri and his M.D. in 1910 through the Johns Hopkins University School of Medicine. Dandy worked one year with Dr. Harvey Cushing in the Hunterian Laboratory of Johns Hopkins before entering its boarding school and residence in the Johns Hopkins Hospital. He worked in the Johns Hopkins College in 1914 and remained there until his death in 1946. One of the most important contributions he made for neurosurgery was the air method in ventriculography, in which the cerebrospinal fluid is substituted with air to help an image form on an X-Ray of the ventricular space in the brain. This technique was extremely successful for identifying brain injuries. Dr. Dandy was also a pioneer in the advances in operations for illnesses of the brain affecting the glossopharyngeal as well as Meniere's syndrome, and he published studies that show that high activity can cause sciatic pain.

Safar era
Peter Safar, the first Intensivist doctor, was born in Austria as the son of two doctors. He migrated to the United States after being in a Nazi concentration camp. Safar first got certification as an anesthetist, and in the 1950s he started and praised the "Urgency & Emergency" room setup (now known as an ICU). It was at this time the ABCs (Airway, Breathing, and Circulation) protocols were formed, and artificial ventilation as well as external cardiac massage became popular. These experiments counted on volunteers of its team which only used minimum sedation. It was through these experiments that the techniques for maintaining life in the critical patient were established.

The first surgical ICU was established in Baltimore, and, in 1962, in the University of Pittsburgh, the first Critical Care Residency was established in the United States. It was around this time that the induction of hypothermia in critical patients was also tested.

More recently, the World Association for Disaster and Emergency Medicine was formed, as was the SCCM (Society of Critical Care Medicine).