CHAPTER 1
INTRODUCTION
1-1 PROBLEM STATEMENT:
Burns are one of the most cases that cause extreme pain and also make the patient unable to sleep or sit for a long time. Also it is known how difficult to treat patients with severe (strong) burns in large or sensitive areas of the body. In such case it is impossible to use standard beds for this kind of patients, but we need beds with special features such as:
1. Keep the patients skin dry and maintain its temperature at a reasonable degree.
2. Absorb the fluids that body excretes to prevent inflammation.
3. Allow regular patient movement to prevent bed sores.
4. Decrease the pressure on the skin to help blood flow, leading to pain reduction and faster healing.
So we believe that the Air Fluidized Bed (CLINITRON) is a satisfactory solution to this problem. It is not only useful for burn patients but also for long-term patients and those from whom it is necessary to exfoliate superficial skin like layer in their dorsal region.
1-2 SCOPE OF STUDY:
The scope and general objectives of the present work are:
The design, construction and installation of the Air Fluidized Bed (Clinitron). The Clinitron should be simple in design, easy to maintain, cheap and provides the lowest interface pressures and greatest sheer reduction of all support beds. To achieve these objectives a literature survey has been made to know the most common types of Clinitron used for heavily burned patients and simulate an actual model for the Clinitron.
CHAPTER 2
BURNS AND THE CLINITRON
2-1 INTRODUCTION:
The heavily burned people are more sensitive to pain than others. In addition they need to lie on the bed for long time. Therefore, the normal beds become unsuitable for these types of patients. They need a special type of beds which should be suitable for their requirements. So the thinking and developing the Air Fluidized Bed (Clinitron) was the aim of some researchers and medical companies. The main features of this bed that it gives some kind of movement to prevent bed sores. Because of that bed was used mainly for heavily burned people. In the following sections we will describe the main types and degree of burns as well as Clinitron types, design and parts.
2-2 BURNS:
2-2-1 Definition:
It is the destruction of the tissues due to exposure to heat whatever its source or type.
2-2-2 Types of Burns (According to the Type of Heat):
a. Dry burn: cause by dry heat.
b. Moist burn: caused by moist heat.
c. Chemical burn: caused by corrosives.
d. Electric burns.
e. Radiation burns.
2-2-3 Classification of Burns:
According to the changes or tissue destruction:
a. 1st degree: redness of the skin due to hyperemia.
b. 2nd degree: formation of vesicles full of fluid.
c. 3rd degree: destruction of the superficial layer of the skin.
d. They were 4th degree: destruction of the whole skin thickness.
e. 5th degree: destruction of SC tissues and muscles.
f. 6th degree: complete charring of tissues.
2-2-4 Factors Affecting the Prognosis of Burns:
Factors taken into consideration in giving the priority for a patient on another to be treated on the Clinitron:
a. Extent of the burns: involvement of more than 1/3 of the body surface area is very dangerous and may be fatal.
b. Degree of the burns: the 3rd degree is the most painful degree “due to exposure of sensory nerve endings” and the most liable to cause neurogenic shock.
c. Site of the burn: burns of the head and neck, trunk and genitalia are more dangerous than those of the limbs.
d. General health: patients with chronic diseases ‘cardiac, renal, hepatic’ can not tolerate burn as healthy people and are more liable to death.
e. Age: children and elderly are more affected than adults.
f. Females and some susceptible persons are more liable to neurogenic shock.
2-3 ANOTHER USE OF CLINITRON:
a. Orthopedic Surgery:
All problems or traction during post-operative immobilization, and after major surgery.
b. Plastic Surgery:
Skin grafts and flap rotation, healing of donor sites treatment of pressure sores, treatment of skin loss.
c. Physiotherapy:
Prevention and treatment of pressure sores, passive Physiotherapy.
d. General Surgery:
Pyonidal cysts; those patients who would have difficulty in moving in the immediate post-operative period.
e. Intensive Cares:
Ideal support for Post-operatives, the comatose patients under myorelaxants, and make control of hypothermia and hyperthermia
f. Cancer:
Reduces pain for patients suffering from skeletal cancer.
2-4 TYPES OF CLINITRON:
This system was first described by Hargest and Artz of South Carolina University in 1968 and it is basically used in burns treatment.
2-4-1 Clinitron at Home:
The CLINITRON AT-HOME Air Fluidized Therapy Unit is designed especially for home care patients who require the unique benefits of an air fluidized support surface to treat full thickness wounds. It provides the lowest interface pressures and greatest sheer reduction of all special support beds.
Fig. 2.1Clinitron at home
2-4-1-1 Features & benefits:
a. Small Particle Fluidization:
Air is channeled through microspheres or beads which sets them in motion and creates a fluid effect that supports the patient.
b. Push Button Head Elevation:
Patients or caregivers can easily elevate or lower the head of the bed in seconds with one touch effort. Head elevation simplifies postural changes and feeding on the unit.
c. Installs in Homes:
This bed is aesthetically pleasing in most home decors and its modular design allows the bed to fit through small stairways and halls.
2-4-1-2 Dimensions and Weight:
Overall length: 234.4 cm
Width: 91.4 cm.
Height: 90 cm; Height of headboard: 119.5 cm.
Total weight without patient: 567 kg.
2-4-2 Clinitron Air Fluidized Therapy Unit:
fig. 2.2 Clinitron Air Fluidized Therapy Unit
2-4-2-1 Dimensions and Weight:
Overall length: 223 cm
Width: 91.5 cm; Height: 90 cm.
Ground clearance: 16 cm.
Weight empty: 220 kg, Clinispheres: 650 kg.
Total weight without patient: 870 kg.
Fig. 2.3 Dimension of Air Fluidized Therapy Unit
CHAPTER 3
EXPREMENTAL WORK
3-1 INTRODUCTION:
The aim of the present work is to design a prototype of clinitron. This clinitron is required to be easy for use, simple in design and cheap. The air fluidized bed (CLINITRON) uses the principle of "floatation", obtained by the means of pumping a weak air using a compressor through a diffuser to a special filter sheet layer which the patient is laying on. The bed temperature is controlled by temperature controller.
The component of the bed can be divided into 2 main categories:
a. Non electrical components.
b. Electrical components.
3-2 NONELECTRICAL COMPONENT:
There nonelectrical components consist of 8 units:
1. Air filter.
2. Blower.
3. Heat exchanger.
4. Heating device.
5. Plenum chamber and diffuser.
6. Fluidizing tank.
7. Microspheres.
8. Filter sheet.
Fig. 3.1
3-2-1 Air Filter:
The air, as it enters the CLINITRON, is cleared of dust and suspended particles by a filter similar to that used in motor cars (porosity of the filter: 5 microns).
3-2-2 Blower:
Fig. 3.2 Blower
The air fluidized bed (Clinitron) uses the principle of "floatation", obtained by the means of pumping a weak air using a compressor through a special filter sheet which the patient is laying on. For this purpose, an electric blower of 350 watt has been used for pumping the air to the bed system.
This energy is sufficient for giving a certain movement in the microsphere which carries the filter sheet. Due to compressing the air by the blower, the air temperature increases about 10°C to 12°C above the ambient temperature. So the equipment is supplied with a cooling system which is used for decreasing the air temperature to the required range.
The blower noise is eliminated either by the muffler situated at the entry to the blower, or by the sound insulation material lining the metallic cabinet.
3-2-3 Heat Exchangers (Cooling System):
Fig. 3.3 Cooling System
The temperature of air inside the clinitron should be controlled within a certain range to achieve the suitable range of temperature for each patient. This requires a cooling and heating system inside the Clinitron system.
Due to the adiabatic rise of air temperature due to blowing it from atmosphere pressure to a high pressure head, the air passes through a water heat exchanger (cooling system) to decrease its temperature. This heat exchanger unit is shown in Fig 3.3
3-2-4 Heating Device:
Fig. 3.4 Heater Fig. 3.5
An electronic heater is placed between the cooling system and the tank that containing the microspheres to heat the air coming from the heat exchanger. The final temperature is obtained by passing the air over this electric heater which is controlled by the temperature probe system located in the microspheres. The system temperature is displayed and controlled through the control panel.
3-2-5 Plenum Chamber and Diffuser:
Fig. 3.6 Plenum Chamber
To get a uniform air pressure and also to make sure that the air is uniformally distributed across the microsphere, the air is firstly collected at a tank "plenum chamber" covered with the diffuser. The diffuser looks like a wooden sheet with small pores. It allows the air to distribute uniformally at low velocity to the fluidization tank "where the microsphere is stored".
At the same time the diffuser doesn't allow the microsphere for passing through to the plenum chamber. Fig 3.6, 3.7, 3.8 show the photos of plenum chamber and diffuser.
Fig.3.7 Diffuser Fig. 3.8
3-2-6 Fluidizing Tank:
Fig. 3.9
The temperature controlled air leaves the diffuser in to the fluidizing tank filled with the microsphere (Fig 3.9). Before filling the tank with microspheres the sieve should be put in place, taking care not to damage the thermometer. The microsphere is, then poured into the tank to a depth of approximately 5cm. (fig 3.10) shows microspheres when the compressed air enter and when it stops.
Particle in Particle in
Particle in Particle in
Fluidizing tank Fluidizing tank
When the compressed when the compressed
Air entered to it air stopped
Principle of fluidization
Fig. 3.10
3-2-7 The Microspheres:
3-2-7-1 General information
The microspheres used in the CLINITRON have a diameter of between 50 and 150 microns. Their perfect shape allows limitation of the airspeed necessary for their fluidization. They are made of soda lime glass with silicone coating making them less sensitive to humidity. These microspheres do not represent any danger; either for the patient or for medical stuff. They are not dangerous for the eyes, the respiratory tract, or digestive system. If accidentally in contact with wounds, these microspheres will not cause any harm. They have, in fact, bactericidal and homeostatic properties. However if for some reason microspheres are lying on the floor, they make it very slippery and so should be removed quickly.
3-2-7-2 Decontamination of the microspheres:
The presence of a patient on the CLINITRON is a permanent source of bacteria. The liquids containing these bacteria cross the filter sheet and with the microspheres progressively form solid conglomerates which are heavier than the fluid. These clumps fall through gravity to the bottom of the tank on to a removable sieve, which enables their easy elimination each week.
Fig. 3.11 How the microspheres work
In the presence of humidity, the soda-lime glass microspheres form an alkaline mixture with a pH of 9 which is a very hostile environment to bacteria.
3-2-8 Filter Sheet:
It is made from special material that h pores. The pores don’t allow micro-spheres to get through. At the same time it allows fluids to go through it to powder.
3-3 ELECTRICAL COMPONENT:
3-3-1 General Block Diagram:
3-3-2 Power Supply:
It is the main power supply in the equipment and it supplies all circuit.
3-3-2-1 Block diagram:
3-3-2-2 Circuit diagram:
3-3-2-3 Power supply components:
a. Transformer:
We used center-tap transformer to convert the voltage from 220V to 16V. -16V with current 2A. In our power supply we need circuit with output 5V, 12V.
b. Bridge:
It main property to convert the current from AC current to DC current.
c. Filters:
It is L.P.F and it used to smoothing the signal and gives it shape of DC current with some ripple, we used capacitor with high value 1000µF as L.P.
d. Regulators:
It is device to make the current pure stable DC current.
3-3-3 Pulsator:
3-3-3-1 Circuit diagram:
3-3-4 Mechanical Switch:
It has 3 positions:
a. Pulsating:
On time: 15 sec, 30 sec, 45 sec …
Off time: 80 sec, 160 sec, 240 sec …
b. Off.
c. Continuous.
3-3-5 Temperature Controller:
3-3-5-1 General description:
It is a one-intervention point electronic temperature controller specially designed for controlled the temperature.
The differential shall be set to positive values; the compressor cuts off at set point and is started at a temperature of set point plus differential.
3-3-5-2 Front keypad:
a. SET: The set point can be changed within 15 seconds with the "up" or "down" button. The new value is automatically stored after 15 seconds since the last operation.
b. UP: Used to increase the set point value, as well as the parameters when in programming. When held down for a few seconds, the change rate accelerates.
c. DOWN: Used to decrease the set point value, as well as the parameters when in programming mode. When held down for a few seconds, the change rate accelerates.
d. Led "OUT": Led related to the compressor relay.
e. Led "SET": Blinks during set point display/change and programming mode.
3-3-5-3 Parameter programming:
Programming is accessed by holding the "SET" button down for more than 5 seconds. The first parameter label is displayed; other parameters are accessed with the "UP" and "DOWN" button, the current setting of each parameter is displayed. To change a parameter setting. Push the "UP" or "DOWN" key. New values are stored on exiting programming mode (when no key is pressed for 15 seconds).
3-3-5-4 Description of parameters:
Parameter / Description / Range / Default / UnitLS
HS
d
ct
cd
cP
On
OF
od
Lc
dr
CA
tA / lower set
higher set
differential
compressor type protection
compressor delay protection
compressor Probe Protection
time(compressor)on
time(compressor)off
output delay at power-on
lock keyboard
display read-out
calibration
table of parameters / -50…set point
set point...50
-12…12
0…3
0…99
of/on/dc
1…99
1…99
0…99
n / y
ْ C/ ْ F
-12…12
/ / -50
50
2
0
0
of
5
5
0
n
ْ C
0
/ / ْ C/ ْ F
ْ C/ ْ F
ْ C/ ْ F
number
min / sec
flag
minutes
minutes
minutes
flag
flag
ْ C/ ْ F
/
Table. 3.1