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Clean, clear and bright light is paramount to all medical staff

A hospital’s number one precedence is patient care. Improving patient care has become a priority for all health care providers with the overall objective of achieving a high degree of patient satisfaction.

‘The Australian health system is world-class in both its effectiveness and efficiency: Australia consistently ranks in the best performing group of countries for healthy life expectancy and health expenditure per person.’ (Doctor connect, 2015)

The quality of patient care is essentially determined by the quality of infrastructure, quality of training, competence of personnel and efficiency of operational systems. However, fundamental to any hospital effectiveness is the quality of medical and technical expertise and the equipment in practice. One (of the many) crucial aspects of medical diagnosis is from clinical observation.

Regular measurement and documentation of clinical observations are essential requirements for patient assessment and the recognition of health deterioration. An important aspect of medical diagnosis through clinical observation is the reliable detection of Cyanosis.

Cyanosis is a physical sign where the skin and mucous membranes give off a bluish discolouration, indicating that the oxygen levels in the blood are dangerously depleted. Cyanosis is associated with cold temperatures, heart failure, lung diseases and smothering. It is seen in infants at birth as a result of heart defects, respiratory distress syndrome, or lung and breathing problems. (Gale Encyclopedia of Medicine, 2008) While pulse oximeters are used in operating rooms and recovery areas, there are areas within hospitals where these are not universally used and there are some medical conditions, for example where patients have poor peripheral circulation, which can make their use unreliable. In such instances,the ability of medical staff to reliably detect the onset of cyanosis by visual observation may be critical to a patient’s health and well being.

Colour is observed by reflection of light from objects. Daylight or artificial light sources are not optimal for detecting cyanosis. The detection of cyanosis requires an adequate light wavelength of around the 660nm. (Midolo, 2007) If the output is too low a patient’s skin colour may appear darker and they may be misdiagnosed. Subsequently, if the output is too high it may disguise the cyanosis and it may not be diagnosed when it is in fact present. The underlying key is that clinical staff cannot rely on visual detection alone.

Extensive clinical trials carried out at Royal Prince Alfred Hospital in Sydney in the early 1970s identified a number of lamps that were suitable for reliable diagnosis of cyanosis. This led to the publication of AS 1765:1975 which included a graphical method of determining which lamps were suitable based on colour temperature and the colour rendering indices Ra and R13. An outline of the method can be found in AS/NZS 1680.2.5:1997 Appendix H.4

The lamps identified in the 1970s used halo-phosphor technology and generally had a continuous spectrum. In the 1980s, however, tri-phosphor lamps entered the market and over a period of time have replaced halo-phosphor lamps except for special purposes. Tri-phosphor lamps provide major efficacy and life benefits.

As part of a review of AS 1680 in the 1990s, Standards Australia Committee LG/1, Interior Lighting, revisited hospital lighting. Resources were not available to carry out the large scale trials of the 1970s, which had established the original cyanosis observation criteria. However, using the data from the first trials and the known reflective properties of blood, a methodology for calculating a Cyanosis Observation Index (COI) was established and published in AS 1680.2.5:1997. This publication sets out lighting recommendations for a variety of tasks carried out within hospitals and medical facilities, specifically for particular tasks associated with clinical observation, treatment and care.

The COI is a dimensionless number and is calculated from the spectral power distribution of a lamp. The methodology calculates the colour difference between blood viewed under the test lamp and when viewed under the reference lamp. To meet the Australian Hospital Standard and be suitable for detecting cyanosis in hospitals, all lamps must meet two criteria: a Cyanosis Observation Index of less than 3.3 and a colour temperature between 3200K and 5500K. Lamps with colour temperatures above 5500K provide false positive diagnoses of cyanosis and lamps with colour temperatures below 3200K results in failure to detect cyanosis.

During the development of the COI method and leading up to the publication of AS 1680.2.5:1997 a number of different lamps were assessed. At this time no triphosphor lamps or triphosphor based lamps were found to comply. It should also be noted that normal tungsten (incandescent) or tungsten halogen lamps generally do not meet the AS/NZS1680.2.5:1997 criteria although some special high colour temperature or filtered light sources will comply.

Modern lamps use rare earth-based phosphors which provide better colour rendering and provide more light output. Fluorescent lamps commonly in use may not have a continuous spectrum. When selecting lamps for the reliable diagnosis of cyanosis, Hospitals need to ensure that the lamps chosen have a COI of 3.3 or lower, have a colour temperature between 3200K and 5500K and are long lasting and cost effective.

In meeting such strict requirements, the COI compliant Hitachi AAA tube was developed. The Hitachi AAA tube uses a new type of high colour rendering phosphor for the highest CRI of 98 emitting the closest light output to natural light and reproduces all colours accurately. This fluorescent tube is suitable for hospital lighting applications in operating theatres, patient treatment rooms, consultation rooms, accident emergency areas and other areas that require close colour rendition of skin.

Since the research and work carried out based on the publication of AS/NZS 1680.2.5:1997 and prior in 1970, there are now several lamp types available in Australia that meet the COI and colour temperature requirements of AS/NZS 1680.2.5:1997. The Hitachi AAA fluorescent tube has a COI of 3.0, a colour temperature of 5000K and the highest colour rendition index of all lamps currently on the market.

Selection criteria for lamps for clinical observation:

The following selection criteria should be taken into account when selecting lamps for the reliable diagnosis of cyanosis:

  • COI of 3.3 or lower
  • colour temperature between 3300 K and 5300 K
  • lamp price
  • lamp availability
  • lamp life
  • lamp efficacy
  • lumen maintenance
  • lamp range

Moreover, with the continual influx of new technologies and the shift in focus for sustainable, energy efficient products, hospitals are continuing to look to the benefits of COI compliant LED lighting. LED technology has largely progressed and the technical development of LED continues to stride ahead.

Hospitals and healthcare facilities have some of the most rigorous lighting requirements of any setting. Clean, clear and bright light is paramount to all medical staff, whilst warm and welcoming environments can promote tranquillity for patients and visitors and denote safety. Hospital lighting must support the overall integrity of the most general – to the most highly specialised health care environments within the facility.

With such abundant amounts of electricity usage to be exercised, alongside the increasing outward cost pressures, it is paramount that hospitals make use of the benefits of LED lighting and its energy efficiency.

‘Energy efficiency’ entails using less energy to achieve the same level of outcome, or improved level of outcome for the same amount of energy. Improving energy efficiency offers economic benefits as it reduces energy consumption and thus energy expenditure. In an environment of increasing energy prices energy efficiency could stabilise energy expenditure.

Today’s LED lights are also more than 5 times energy efficient than conventional incandescent lights, cut energy use by more than 80 percent and can 10 times longer. The longer service life, reduced maintenance and lower energy requirements of LEDs result in substantial overall savings for any hospital or clinic.

Along with advantages such as energy-efficiency and controllability, the use of LEDs can help facilities managers lower maintenance costs because of their longevity. Hospital staff will spend less time maintaining the lighting and changing bulbs, which in turn potentially reduces the risks of install injuries such as ladder climbing, resulting in fewer accidents and work compensation claims.

Victorian public health services have been implementing energy efficiency initiatives for over ten years. Some of the more common initiatives include:5

  • installing more efficient lighting such as LED
  • installing lighting controls, for example motion sensors in infrequently occupied rooms, such as store rooms
  • installing variable speed drives for fans or pumps
  • installing newer and more efficient air-conditioning plant
  • installing air-conditioning controls such as time controllers that switch equipment off after hours
  • improving the maintenance of building systems.

Hospitals are focused on patient care and the patient experience, and lighting greatly influences the comfort of staff and patients. It is critical to foster environments that protect and promote the health and wellbeing of communities. The health and medical department plays a key role to communicate the importance of the natural and built environments to health and wellbeing of people.


1. Doctor Connect. (2015). Australia’s health system – an overview.
Retrieved April 28 2015 from http://www.doctorconnect.gov.au/internet/otd/publishing.nsf/Content/australiasHealthSystem

2. For Gale Encyclopedia of Medicine: cyanosis. (n.d.) Gale Encyclopedia of Medicine. (2008). Retrieved April 28 2015 from

3. Midolo, N.A. (2007) Lighting for clinical observation of cyanosis.
Retrieved April 28 2015 from

4. AS/NZS 1680.2.5:1997, Interior lighting, Part 2.5:
Hospital and medical tasks, Standards Australia, 1997

5. Sustainability in Healthcare (n.d.).
Retrieved from http://www.health.vic.gov.au/sustainability/energy/efficiency.htm 

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