Design and organisation of intensive care units

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Chapter 1 Design and organisation of intensive care units

An intensive care unit (ICU) is a specially staffed and equipped area of a hospital dedicated to the management of patients with life-threatening illnesses, injuries or complications. ICUs developed from the postoperative recovery rooms and respiratory units of the 1920s, 1930s and 1940s when it became clear that concentrating the sickest patients in one area was beneficial. Intermittent positive-pressure ventilation (IPPV) was pioneered in the treatment of respiratory failure in the 1948–1949 poliomyelitis epidemic and particularly in the 1952 Copenhagen poliomyelitis epidemic when IPPV was delivered using an endotracheal tube and a manual bag.1 Subsequently mechanical ventilators were developed and became increasingly used for the treatment of thoracic surgery, general surgery, tetanus and ‘crushed chests’.

The 1970s saw a heightened interest in intensive care medicine, with research into the pathophysiological processes, treatment regimens and outcomes of the critically ill and the founding of specialty journals, training programmes and qualifications dedicated to intensive care. Modern intensive care or critical care medicine is not limited to postoperative care or mechanical ventilation. It is a separate specialty and, although some period of training in an ICU is valuable to all specialties, it can no longer be regarded as ‘part of’ anaesthesia, medicine, surgery or any other discipline.

As outlined below, the ICU is not just a ward but a department with dedicated medical, nursing and allied health staff: it operates with defined policies and procedures and has its own quality improvement, continuing education and research programmes. Through its care of critically ill patients in the ICU and its outreach activities (see Chapter 2), the intensive care department provides an integrated service to the hospital, without which many programmes (e.g. cardiac surgery, trauma, transplantation) could not function.


The delineation of roles of hospitals in a region or area is necessary to rationalise services and optimise the use of resources. Each ICU should similarly have its role in the region defined and should support the defined duties of its hospital. In general, small hospitals require ICUs that provide basic intensive care. Critically ill patients who need complex management and sophisticated investigative back-up should be managed in an ICU located in a large tertiary referral hospital. Three levels of adult ICUs are classified as follows by the Joint Faculty of Intensive Care Medicine (Australia and New Zealand).2 The European Society of Intensive Care Medicine has a similar classification.3 The American College of Critical Care Medicine also has a similar classification but uses a reversed-numbering system.4 It should be noted that full-time directors and directors with qualifications in intensive care medicine are less common in the USA,5 as are the requirement for a dedicated doctor for the ICU around the clock and referral to the attending ICU specialist for management.6

The classification of types of ICU must not be confused with the description of critical care beds throughout a hospital, as with the UK classification of critical care beds (Table 1.1).

Table 1.1 UK classification of critical care beds

Level 0
Patients whose needs can be met through normal ward care in an acute hospital
Level I
Patients at risk of their condition deteriorating, or those recently relocated from higher levels of care whose needs can be met on an acute ward with additional advice and support from the critical care team
Level II
Patients requiring more detailed observation or intervention, including support for a single failing organ system or postoperative care, and those stepping down from higher levels of care
Level III
Patients requiring advanced respiratory support alone or basic respiratory support together with support of at least two organ systems. This level includes all complex patients requiring support for multiorgan failure (


Within each of these classifications, an ICU may not be able to provide intensive care for all subspecialties, or may need to be more oriented towards a particular area of expertise (e.g. neurosurgery, cardiac surgery, burns or trauma). An institution may organise its intensive care beds into multiple units, under separate management by single-discipline specialists, for example, medical ICU, surgical ICU and burns ICU. Although this may be functional in some hospitals, Australasian experience has favoured the development of general multidisciplinary ICUs. Thus, with the exception of dialysis units, coronary care units (CCUs) and neonatal ICUs, critically ill patients are admitted to the hospital’s multidisciplinary ICU and are managed by intensive care specialists (or paediatric intensivists in paediatric hospitals).

There are good economic and operational arguments for a multidisciplinary ICU as against separate, single-discipline ICUs. Duplication of equipment and services is avoided. Critically ill patients develop the same pathophysiological processes no matter whether they are classified as medical or surgical and they require the same approaches to support of vital organs. Doctors without intensive care training lack the experience and expertise to deal with the complexities of multiorgan failure.

The number of ICU beds in a hospital usually ranges from 1 to 4 per 100 total hospital beds. This depends on the role and type of ICU. Multidisciplinary ICUs require more beds than single-specialty ICUs, especially if high-dependency beds are integrated into the unit. ICUs with fewer than four beds are considered not to be cost-effective and are too small to provide adequate clinical experience for skills maintenance for medical and nursing staff. On the other hand, the emerging trend of ICUs having 267 or more beds creates major management problems. Although the evidence is scant, there is a suggestion that efficiency deteriorates once the number of critically ill patients per medical team exceeds 12.8 Consequently two or more medical teams may need to work together in these ‘mega-units’.


The ICU should be sited in close proximity to relevant acute areas, that is, operating rooms, emergency department, CCU, labour ward and acute wards, and to investigational departments (e.g. radiology department, cardiac catheterisation laboratory). Safe transport of critically ill patients to and from the ICU should be facilitated by sufficient numbers of lifts and these, with doors and corridors, should be spacious enough to allow easy passage of beds and equipment – vital points often ignored by ‘planning experts’.

There should be a single entry and exit point, attended by the unit receptionist. Through traffic of goods or people to other hospital areas must never be allowed. An ICU should have areas and rooms for public reception, patient management and support services. The whole unit should be 2.5–3 times the area of the specific patient care areas.


Each patient bed area in an adult ICU requires a minimum floor space of 20 m2 (215 ft2), with single rooms being larger (at least 25 m2), to accommodate patient, staff and equipment without overcrowding. The ratio of single-room beds to open-ward beds will depend on the role and type of the ICU, but with a recommended range of between 1:6 and 1:2. They should be equipped with an anteroom of 2.5 m2. Single rooms are essential for isolation and, less importantly, privacy for conscious long-stay patients. The emergence of resistant bacterial strains in ICUs around the world has increased the need for isolation facilities in recent years. A non-splash hand wash basin with elbow- or foot-operated taps should be close to each bed and a hand disinfection facility at each bed.

Bedside service outlets should conform to local standards and requirements (including electrical safety and emergency supply, such as to the Australian Standard, Cardiac Protected Status AS3003).

Utilities per bed space as recommended for a level III ICU are:

Adequate and appropriate lighting for clinical observation must be available. How the services are supplied (e.g. from floor column, wall-mounted, or ceiling-pendant) depends on individual preferences. There should be room to place or attach additional portable monitoring equipment and, as much as possible, equipment should be kept off the floor. Space for charts, syringes, sampling tubes, pillows, suction catheters and patient personal belongings should be available, often in a moveable bedside trolley.

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