WO2005116958A1

WO2005116958A1 - An anatomical simulator

Info

Publication number: WO2005116958A1
Application number: PCT/AU2005/000752
Authority: WO
Inventors: Harry Owen; Karen Reynolds
Original assignee: FLINDERS MEDITECH Pty Ltd
Current assignee: FLINDERS MEDITECH Pty Ltd
Priority date: 2004-05-27
Filing date: 2005-05-27
Publication date: 2005-12-08
Anticipated expiration: 2006-11-27

Abstract

An anatomical simulator simulates colouring of a human being which is indicative of a physiological condition. The anatomical simulator includes a body tissue simulating portion (2), illumination sources (4), and an illumination controller (6). The illumination sources emit light in a plurality of colours and are configured to diffuse light through the body tissue simulating portion. The illumination controller controls the illumination sources to create a colour effect in the body tissue simulating portion which is indicative of a physiological condition.

Description

AN ANATOMICAL SIMULATOR

Field of the Invention

This invention relates to an anatomical simulator for simulating colouring of a human being which is indicative of a physiological condition. In particular, it relates to an anatomical simulator for simulating a change in colour which occurs in response to a change in physiological conditions and a method for simulating the same.

Background to the Invention

Medical training is essential for establishing and maintaining a skilled medical workforce. In the past, many health professionals have been trained to a large degree "on the job" or using traditional classroom learning techniques and hypothetical scenarios. Traditional classroom learning techniques rely on texts and images of actual patients who have presented with particular symptoms in response to which students hypothesise diagnosis and/or treatment. Whilst this is useful for initial training, it does not provide students with a realistic scenario or permit development of real-life patient treatment skills.

More advanced students complete placements in hospitals and other care institutions, or environments where they have an opportunity to put their theoretical learning into practice. However student placements have a major drawback because poor or incorrect treatment resulting from lack of experience or know-how can result in an adverse patient outcome which may be so serious that it causes brain damage or even death.

Patient simulators are increasingly being used in the training of health professionals because they provide a somewhat realistic scenario but do not carry the risk attached to students treating live patients who, in some cases, may already be quite ill. Patient simulators can be used by individuals learning and developing practical skills and by groups of individuals learning to work as a team. Some simulators may provide only a part of the anatomy in relation to which the student is being trained. This may be the head, chest and torso, pelvis, arm, leg, hand or foot. Simulators exist to facilitate training in dentistry and other areas of medicine also. Other "full" body training mannequins exist which are used to teach first aid, including CPR and intubation. Although these mannequins may vary in size, gender, race and age, they do not give a realistic appearance for the physiological conditions they are supposed to simulate.

Existing patient simulators are made from a synthetic material which is representative of the skin and mucous membranes. For these simulators, designers must strike a balance between realism of appearance and feel, and durability and robustness. These simulators generally have the appearance of a "healthy" patient. However, such an appearance may not be realistic in all training scenarios, for example, when a patient is being treated for shock or low blood pressure.

An attempt has been made to use colour in patient simulators whereby blue light is made to shine through the face, hands and feet of a neonatal simulator. These neonatal mannequins are used for training medical staff in ventilation and resuscitation (e.g. by performing chest compressions) of infants and the blue colouring is used to indicate that the neonatal simulator has received ineffective ventilation and/or compressions. It does not give a realistic simulation of an actual colour change in the patient.

The discussion of the background to the invention included herein including reference to documents, acts, materials, devices, articles and the like is intended to explain the context of the present invention. This is not to be taken as an admission or a suggestion that any of the material referred to was published, known or part of the common general knowledge in Australia as at the priority date of any of the claims.

It is an object of the present invention to overcome or ameliorate one or more of the disadvantages of the prior art, or at least to provide a useful alternative. Summary of the Invention

In a first aspect of the present invention there is provided an anatomical simulator for simulating colouring of a human being which is indicative of a physiological condition, the anatomical simulator including: (a) a body tissue simulating portion;

(b) illumination sources; and

(c) an illumination controller; wherein the illumination sources emit light in a plurality of colours and are configured to diffuse light through the body tissue simulating portion, and wherein the illumination controller controls the illumination sources to create a colour effect in the body tissue simulating portion which is indicative of a physiological condition.

In some arrangements, the illumination sources are configured to emit the plurality of colours at the same time in differing proportions.

The illumination sources may be any suitable illumination sources such as cold cathode fluorescence, electro-luminescence, light emitting diodes (LEDs), tricolour LEDs, optical fibres or the like, which are capable of diffusing light through the body tissue simulating portion. An array of illumination sources may also be used. Preferably, the plurality of colours include two or more of red, green and blue although other colours may be used to achieve a desired colour effect.

In one embodiment, the anatomical simulator further includes an illumination conduit configured to deliver light emitted from the illumination sources to the body tissue simulating portion to create the colour effect therein. That is, the coloured light emitted from the illumination sources can be piped or delivered to the body part. This enables the sources, such as LEDs and the like to be positioned away from the specific site of the body tissue simulating portion in which the colour effect is created. This is particularly useful for creating a colour effect in smaller body parts such as the lips, eyes and fingertips etc. The illumination conduit may be provided in any suitable form. However, it has been found that optical fibres are particularly suitable such conduits. Preferably, the anatomical simulator also includes an illumination sensor which senses ambient illumination conditions. A measure of these conditions such as intensity and/or colour can then be used by the illumination controller to adjust the colour effect in order to compensate for ambient illumination conditions, which may otherwise affect the realism or effectiveness of the simulation.

In one embodiment, the illumination controller includes a microprocessor which is pre-programmed to control the illumination sources to create one or more colour effects which correspond to colouring of a human which is indicative of one or more physiological conditions. Preferably, the microprocessor is also configured to control the illumination sources to create a change in colour effect which corresponds to a change in physiological condition. Controlling the illumination sources preferably includes controlling the colour and intensity (or brightness) of the illumination sources.

In one embodiment, the illumination controller is operable in isolation. As an alternative, the illumination controller may be integrated with another simulation device or system or another control system.

The body tissue simulating portion may be manufactured from any material or combination of materials in which light may be diffused. Preferably this includes urethane rubber coloured with a grey dye although other materials such as Perspex, glass and fibreglass etc. may be suitable.

The anatomical simulator may simulate a number of physiological conditions which are identifiable by observing the colour of tissue or a change in the colour of tissue. These physiological conditions may include but are not limited to hypoxia or another blood saturation level, low blood pressure or another blood pressure level, low perfusion or another perfusion level, jaundice, blood loss, or a combination of these. Tissues for which the anatomical simulator may simulate physiological conditions include but are not limited to the lips, skin, a finger or fingertip, a fingernail, a toe or toenail, and the conjunctiva and tissues around the eyes. In a second aspect of the present invention, there is provided a method for simulating colouring of a human being using an anatomical simulator including the steps of: (a) using an illumination controller to control illumination sources; and

(b) diffusing light emitted from the illumination sources in a body simulating portion to create a colour effect; wherein the illumination sources emit light in a plurality of colours and the illumination controller is pre-programmed with one or more algorithms which control the illumination sources to create colour effects simulating colouring of a human being indicative of a physiological condition.

In one embodiment, the method further includes the step of using an illumination conduit to deliver light emitted from the illumination sources to the body simulating portion before diffusing the light to create the colour effect therein. Any suitable conduit capable of delivering the light may be used, although optical fibres have been found particularly suitable.

Preferably, the method also includes detecting ambient illumination conditions and using the illumination controller to adjust the colour effect to compensate for the detected ambient illumination conditions. Detected ambient illumination conditions may include light intensity and/or colour.

In one preferred embodiment, the illumination controller is configured to create a change in colour effect which simulates a colour change in a human in response to a change physiological condition. The illumination controller may operate in isolation. Alternatively, the illumination controller can be integrated with another simulation device or system.

Brief description of the drawings

The present invention will now be described in greater detail with reference to the accompanying drawings. It is to be understood that the particularity of the accompanying drawings does not supersede the generality of the preceding description of the invention.

Figure 1 is a block diagram illustrating components of an embodiment of the invention.

Figure 2A illustrates a schematic for a PIC18F452 microcontroller suitable for controlling the LED array according to an embodiment of the invention. Figure 2B illustrates a schematic for an illumination sensor configured for use as an input to the microcontroller of Figure 2A. Figure 2C illustrates a schematic for user controllable input to the microcontroller of Figure 2A, for controlling the oxygen saturation and blood pressure values used to create the colour effect.

Figure 3 is a graph illustrating the relationship between oxygen saturation and red and blue light illumination over the oxygen saturation range 50% to 100% at a blood pressure level of 120 mmHg.

Figure 4 is a graph illustrating the relationship between blood pressure and green light illumination over the blood pressure range 60mmHg to 120mmHg.

Figure 5 is a graph illustrating the relationship between oxygen saturation and red and blue light illumination over the oxygen saturation range 50% to 100% for a number of blood pressure values less than 120mmHg.

Detailed Description

Referring firstly to Figure 1 , the anatomical simulator includes a body tissue simulating portion 2, an illumination controller 6 and illumination sources 4. Illumination sources 4 emit light in a plurality of colours as determined by the illumination controller, to create a colour effect in the body tissue simulating portion which is indicative of a physiological condition.

It is well understood that one of the first body parts to change colour in response to oxygen deficiency or major blood loss (shock) are the lips. Therefore, health-care professionals are trained to examine the lips as a quick way of determining the likelihood of a patient being hypoxic or in shock. Accordingly, the anatomical simulator of Figure 1 provides the body tissue simulating portion in the form of lips 2.

It is to be understood, however, that the present invention also has applicability to other tissues in which a particular colour or a change in colour can be indicative of a physiological condition. Whilst in most cases these physiological conditions are evident by inspection of skin colouring of a body part such as a fingertip, toe, or lips, applications of the present invention should not be limited to changes in skin colour. The present invention may also be used to create a colour effect or change in colour effect in other tissues such as the fingernails, toenails, or the eyes, or even internal organs to simulate a colouring which is indicative of a physiological condition or change.

Preferably, the anatomical simulator simulates changes in colour which are brought about in humans in response to physiological changes (i.e. changes in physiological conditions). Such physiological changes may include changes in blood pressure and/or blood-oxygen saturation. However, as would be understood by the skilled addressee, colour changes in response to other physiological changes or conditions may also be simulated using the present invention.

In the embodiment illustrated in Figure 1 , illumination sources 4 are provided in the form of an array of tri-colour LEDs. The illumination sources are illuminated in various colour combinations to produce the desired colour effect in the lips. Lips 2 are formed from an opaque urethane rubber material (Clear Flex 50 distributed by Resimax, Adelaide) moulded into the desired shape and applied over the LED array 4 to a supporting surface (not shown). In this embodiment, a more realistic simulation (i.e. colour effect) is achieved by adding a small amount of grey dye to the rubber during the rubber-moulding process although addition of the dye may not be essential.

The urethane rubber material conducts the light emitted from the LED array in such a way that it is diffused through the urethane rubber thereby illuminating the lips by diffusing through them and resulting in a colour effect which is viewed by an observer as a realistic lip colouring for a particular physiological condition.

In an alternative embodiment, the illumination sources may be located away from the body tissue simulating sources and the emitted light may be delivered or piped to the body tissue simulating portion 4. A conduit such as optical fibre cabling 12 illustrated in Figure 1 may be suitable. This is suitable for application of the invention to body parts such as the lips, which may be too small to accommodate the number of illumination sources required to achieve the desired colour effect in their immediate vicinity. Rather, the illumination sources emit light at a distance from the body tissue simulating portion and the light is carried by the conduit to the body tissue simulating portion where the light is diffused. A further advantage is that the LEDs may be located in an area of the simulator which is easier access for maintenance and replacement.

It is desirable that a mannequin incorporating an anatomical simulator according to the present invention can receive treatment from a student in response to physiological conditions which are being simulated. Accordingly, it is also desirable that the illumination conduit is sufficiently flexible or resilient to withstand such treatment without damaging or affecting the operation of the illumination sources. Treatment may include mouth-to-mouth resuscitation, chest compressions or the like. Optical fibres possess a degree of flexibility and therefore are suitable for use as an illumination conduit. In such an embodiment, it is also desirable that the illumination controller is configurable to receive feedback determined by the treatment being administered. This enables the anatomical simulator to change the colour effect according to the treatment giving an even more realistic simulation.

Each pixel of the LED array 4 is made up of matched red, green and blue LEDs which can be combined in different ways to produce rich colours. It is desirable that the illumination sources are sufficiently small and arranged so that the colour effect is smooth and realistic. Accordingly, certain large LED arrays or illumination sources may not be suitable. In some embodiments, it may be desirable to mount a plurality of individually controllable LEDs into an array of any size or shape which is appropriate for the body part being simulated. In some embodiments it is desirable to control the intensity of each LED individually.

Illumination of the LED array is controlled by illumination controller 6. One suitable illumination controller is a Motorola PIC18F452 microcontroller which comes in a 40 pin DIP package. A suitable control circuit for this microcontroller is illustrated in the schematic of Figure 2A. To aid in miniaturisation, microcontroller 6 could be replaced with a smaller quad flat pack (QFP) part for use on a custom made printed circuit board (PCB). Alternatively the control system may be miniaturised into an integrated circuit (IC) or the like.

Whilst microcontroller 6 controls illumination of each of the coloured LEDs in array 4, it is also desirable that the microcontroller controls the brightness of light emitted from the LEDs. Brightness (or intensity) may be adjusted by any suitable means. However, for ease of integration of components, it is preferable that the brightness is adjusted using pulse width modulation, as determined by the microcontroller. It is to be understood that brightness of the array of illumination sources may be controlled together or, the brightness of each source may be controlled individually.

In Figure 1 , illumination sensor 10 is provided in the form of a photodetector configured to measure the ambient lighting conditions and provide an illumination sensor signal to the illumination controller 6. This signal is used by the illumination controller to adjust the overall brightness of light emitted from the LED array. This enables the level of illumination to be adjusted to facilitate use of the anatomical simulator in different ambient lighting environments. For example, when the anatomical simulator is used outdoors during daytime where there is bright ambient lighting, the intensity of the colour effect created by the LED array is increased so that it can be seen easily. Similarly, in dimmer ambient lighting conditions the intensity of the colour effect created by the LED array is decreased so that the LED array doesn't have the appearance of a lamp or beacon. In most instances, in order to create a realistic colour effect which represents the colouring of a human being which is indicative of a physiological condition or a physiological change, a combination of red, green and blue light is required. However, it is also possible that a combination of only two colours of light emitted from the illumination sources may be sufficient to created a desirable colour effect in the body tissue simulating portion. It is also possible that colours other than red, green and blue may be suitable for creating a desired colour effect.

Referring again to the example illustrated in Figure 1 , it has been found that the colour of the lips changes significantly in response to two parameters: oxygen saturation and blood pressure. As oxygen saturation drops, the colour of the lips turns from red to a bluish colour. This may be simulated by controlling illumination of the red and blue illumination sources. As blood pressure drops or blood loss occurs, the lips turn a paler colour. This may be simulated by controlling illumination of a green light source with the blue and red.

It follows that values for oxygen saturation and blood pressure may be used as inputs 8 to the illumination controller 6 to control illumination of the red, blue and green LEDs in LED array 4 to create the desired colour effect. In one embodiment, these inputs are provided in the form user-adjustable buttons (as illustrated in Figure 2C). However, in an alternative embodiment, values for oxygen saturation, blood pressure and parameters for other relevant physiological conditions could be read from another device automatically, or extracted from another application. Such a device may be a control unit for a sophisticated medical mannequin. Alternatively, an algorithm used by another simulation control unit may be used to provide inputs to the microcontroller, or the functionality of the microcontroller may be built into a larger control system.

In the embodiment illustrated, illumination controller 6 determines a control signal (being a number value between 0 and 255) for each of the red, green and blue LEDs using oxygen saturation and blood pressure as parameters in the following cubic relationships. For oxygen saturation, S, an algorithm for determining illumination of the red LED, R is:

R = R₃S³ + R₂S + R,S + R₀ (equation 1)

Similarly, an algorithm for determining illumination of the blue LED, B is:

B = B₃S' +B₂S' + B_lS + B_Q +f(BP) (equation 2)

Typical values of constants R_n and B_n are provided in the following table.

Typical illumination distribution curves are illustrated in Figure 3, showing red and blue illumination content over the oxygen saturation range 50 to 100% for a blood pressure of 120mmHg.

It is to be noted that equation 2 contains a function of blood pressure, f(BP) .

This function is approximately zero at BP = 120 mmHg, but becomes significant as blood pressure drops. It is also to be noted that as the blood pressure drops, the lips appear paler. This colour effect is achieved in the anatomical simulator by increasing the amount of green light emitted from LED array 4. The green light value, G is determined based on the blood pressure value, BP, according equation 3.

G = 497 -BP*4.1 (equation 3)

This is clearly illustrated in Figure 4 which shows a linear relationship between blood pressure and green light illumination over the range 60mmHg to 120mmHg. At 60mmHg (very low blood pressure) green light emission is at a maximum value (255) which will result in a colour effect representative of very pale tissue colouring. That is, as the blood pressure input value is decreased, green light illumination is increased to create a paler colour effect in the lips 2. At 120mmHg (normal blood pressure) green light emission is just above zero.

Figure 5 shows the relationship between oxygen saturation and red and blue light illumination over the oxygen saturation range 50% to 100%. It has been found that when using equations 1 , 2 and 3 to create the colour effect, the extra green light causes an undesirable yellow tinge for oxygen saturation values above approximately 85%. To overcome this, for values of oxygen saturation greater than 85%, the amount of blue light emitted should be slightly increased. This new colour effect can be summarised in equations 2A and 2B. or S < 85% B = B₃S³ +B₂S² +B_{S + B₀ (equation 2A) or S ≥ 85% B (equation 2B)

This is clearly illustrated in Figure 4 which shows an increase in the amount of blue light emitted as blood pressure decreases (simulated by an increase in the amount of green light emitted), for oxygen saturation levels above 85%.

Equations 1 to 3 are suitable only for generating values for R, G and B between 0 and 255. If these equations produce a value forR, G or B which exceeds 255, then illumination effect of the respective LED will be restricted to a maximum value of 255. Similarly, if the equations produce a value for R, G and B which is less than zero, then the illumination effect of the respective LED will be zero.

It is to be understood that the present invention may be used to simulate a colour effect in a number of model body parts simultaneously to create a realistic anatomical model. Such a model may include lips, fingertips and eyes that simulate a colour response to physiological conditions or physiological changes which are provided as inputs to an illumination controller. Use of an array of tri-colour LEDs enables fine control of the colour effect to give a realistic simulation.

The formulae specified herein facilitate continuous variation in the colour effect to simulate realistic and smooth colour changes as exhibited by actual patients experiencing certain changes in physiological conditions. This has obvious advantages over look up tables which may only allow incremental changes in the colour effect and which would result in a less realistic simulation. The system can also be scaled readily for use in both small (neonatal) and large (adult) simulators. Whilst formulae are specified herein, it is to be understood that numerous different algorithms may be derived to create a desired colour effect whilst remaining within the scope of the invention. Accordingly, the present invention should not be limited by reference to the particular formulae specified herein.

An advantage of the present invention is that the body tissue simulation portion is not directly illuminated on a surface which is viewed by an observer. Rather, use of the illuminating sources in the present invention causes the body tissue simulation portion to become illuminating by diffusing light through the material from which it is formed.

A further advantage is that the present invention enables illumination to be modified according to the ambient illumination conditions. This enables light diffused from the anatomical simulator to be viewed in a wide range of conditions, both indoors and out, without the problem of the illumination sources appearing like a beacon. Also, the use of urethane rubber with grey dye added enables realistic simulation of colouring of the lips and other tissues for very low simulated oxygen levels (severe hypoxia). Moreover, varying the proportion of green light emitted from the illumination sources in combination with controlled amounts of blue and red light enables clinically realistic hues to be simulated for a range of blood pressure conditions and oxygen saturation conditions. It is to be understood that various modifications, additions and/or alterations may be made to the parts previously described without departing from the ambit of the present invention as defined in the claims appended hereto.

Claims

1. An anatomical simulator for simulating colouring of a human being which is indicative of a physiological condition, the anatomical simulator including: (a) a body tissue simulating portion;

(b) illumination sources;

2. An anatomical simulator according to claim 1 wherein the illumination sources include one or more of the following:

(a) light emitting diodes (LEDs);

(b) tricolour light emitting diodes;

(c) optical fibres;

(d) Cold cathode fluorescence; and (e) Electro-luminescence.

3. An anatomical simulator according to claim 1 or claim 2 wherein the illumination sources emit the plurality of colours at the same time in differing proportions.

4. An anatomical simulator according to any one of claims 1 to 3 further including an illumination conduit configured to deliver light emitted from the illumination sources to the body tissue simulating portion to create the colour effect therein.

5. An anatomical simulator according to claim 4 wherein the illumination conduit includes one or more optical fibres.

6. An anatomical sensor according to any one of the preceding claims further including an illumination sensor for detecting ambient illumination conditions, wherein the illumination controller adjusts control of the illumination sources to compensate for the sensed ambient illumination conditions.

7. An anatomical simulator according to claim 6, wherein the illumination controller adjusts the intensity of light emitted from the illumination sources to compensate for the sensed ambient lighting conditions.

8. An anatomical simulator according to any one of the preceding claims wherein the illumination controller includes a microprocessor pre-programmed to create one or more colour effects which correspond to physiological conditions and is configured to create a change in colour effect to simulate a change in physiological condition by controlling illumination of the one or more illumination sources.

9. An anatomical simulator according to any one of the preceding claims wherein the illumination controller is operable in isolation.

10. An anatomical simulator according to any one of claims 1 to 9 wherein the illumination controller is integrated with another simulation device or system.

11. An anatomical simulator according to any one of the preceding claims wherein the body tissue simulating portion is manufactured from a material which includes urethane rubber coloured with a grey dye.

12. An anatomical simulator according to any one of the preceding claims wherein the physiological conditions being simulated include one or more of:

(a) hypoxia; (b) other blood saturation level;

(c) low blood pressure;

(d) other blood pressure level;

(e) low perfusion; and

(f) other perfusion level.

13. An anatomical simulator according to any one of the preceding claims wherein the body tissue simulating portion represents one or more of the following body tissues: (a) lips;

(b) skin;

(c) a finger or fingertip;

(d) a fingernail;

(e) a toe; (f) a toenail;

(e) eyes; and

(f) internal organs.

14. An anatomical simulator according to any one of the preceding claims wherein the plurality of colours include two or more of red, green and blue.

15. A method for simulating colouring of a human being using an anatomical simulator, including the steps of:

(a) using an illumination controller to control an array of illumination sources; and

(b) diffusing light emitted from the illumination sources in a body simulating portion of the anatomical simulator to create a colour effect; wherein the illumination sources emit light in a plurality of colours and the illumination controller is pre-programmed with one or more algorithms which control the illumination sources to create a colour effect simulating colouring of a human being which is indicative of a physiological condition.

16. A method for simulating colouring of a human being according to claim

15 further including the step of using an illumination conduit to deliver light emitted from the illumination sources to the body simulating portion to create the colour effect therein.

17. A method for simulating colouring of a human being according to claim

16 wherein the illumination conduit includes one or more optical fibres.

18. A method for simulating colouring of a human being according to any one of claims 15 to 17 further including the steps of:

(a) detecting ambient illumination conditions; and (b) using the illumination controller to adjust an intensity of the colour effect to compensate for the detected ambient illumination conditions.

19. A method for simulating colouring of a human being according to any one of claims 15 to 18 wherein the illumination controller is configured to create a change in colour effect, which simulates a colour change in a human, which is indicative of a change in physiological condition.

20. A method for simulating colouring of a human being according to any one of claims 15 to 19 wherein the illumination controller operates in isolation.

21. A method for simulating colouring of a human being according to any one of claims 15 to 19 wherein the illumination controller is integrated with another simulation device or system.

22. A method for simulating colouring of a human being according to any one of claims 15 to 21 wherein the physiological condition includes oxygen saturation S , with a corresponding colour effect created by illumination of at least a red illuminating source.

23. A method for simulating colouring of a human being according to any one of claims 15 to 22 wherein the physiological condition includes oxygen saturation S , with a corresponding colour effect created by illumination of at least a blue illuminating source.

24. A method for simulating colouring of a human being according to claim

22. wherein illumination of the red illumination source is determined by the following algorithm: R = R₃S³ +R₂S² + R_lS + R₀ where: R₃ = 7.82*10^"3 ; R₂ =-2.241 ; R, = 214.9 ; and R₀ = -6642 .

25. A method for simulating colouring of a human being according to claim 23, wherein physiological condition further includes blood pressure, BP , and illumination of the blue illumination source is determined by the following algorithm: B = B₃S³ + B₂S² + B,S + B₀ + f(BP) where: f(BP) = 0 for BP = 120mmHg; and B₃ = -3.90*10^"3 ; B₂ = 1.153 ; B = -115.7 ; and 5₀ = 3939 .

26. A method for simulating colouring of a human being according to any one of claims 15 to 25 wherein illumination of a green illumination source creates a colour effect indicative of blood pressure, BP .

27. A method for simulating colouring of a human being according to claim 26 wherein illumination of the green illumination source is determined using the following algorithm: G = 497 -BP* 4.1 .

28. A method for simulating colouring of a human being according to any one of claims 15 to 27 wherein:

(i) for S < 85% B = B₃S³ +B₂S² +B_]S + B₀ ; and

(ii) for S > 85% B = B₃S³ + B₂S² ÷ B + B_o + G * (S -85, 3 15 where: S is oxygen saturation; B determines illumination of a blue illumination source; R determines illumination of a red illumination source; and G determines illumination of a green illumination source.

29. An anatomical simulator substantially as hereinbefore described with reference to any one of the embodiments exemplified, or illustrated in the accompanying drawings.

30. A simulator including an anatomical simulator for simulating physiological conditions of a human being according to any one of the preceding claims.

31. A method for simulating colouring of a human being substantially as hereinbefore described with reference to any one of the embodiments exemplified, or illustrated in the accompanying drawings.