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July 2010_eng_05

Incubators

How to choose the best A sensible Guide

to the choice of an Incubator

Incubators - How to choose the best 2

July 2010_eng_05

INDEX:

FUNDAMENTAL CHARACTERISTICS ............................................................7

CHOICE OF MATERIALS....................................................................................9

FUNCTION ............................................................................................................10

GOOD WORKING ORDER ................................................................................11

UNIVERSITY OF CAGLIARI.............................................................................13

NOISE .....................................................................................................................19

STANDARD HUMIDIFIER .................................................................................20

OPENING THE DOORS ......................................................................................21

MAINTAINING THE INCUBATOR INTERNAL HEAT LEVEL WITH THE DOORS OPEN .......................................................................................................22

CRITERION FOR THE CHOICE OF INCUBATOR TYPE...........................24

HUMIDIFICATION SYSTEM CONSIDERATIONS.......................................26

COMPARISION BETWEEN INCUBATOR HOODS MADE OF ACRYLIC AND POLYCARBONATE (LEXAN)..................................................................27

CHARACTERISTICS OF “LEXAN” POLYCARBONATE ...........................28

CONSIDERATIONS ABOUT THE USEFULNESS OF A DOUBLE HOOD29

HEAD BOX MICRO-CLIMATE.........................................................................31

HEATING WITH A HOT AIR BARRIER ACROSS AN OPEN DOORWAY32

TECHNICAL REPORT ON GINEVRI INCUBATORS ..................................35


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PREFACE

It is with great satisfaction that I read this step-by-step guide to the choice of a neo-natal incubator

and, once again, I must acknowledge the deep insight of “Ginevri srl” into the world of neo-natal

incubators.

In the last 30 years this company has designed and manufactured “made in Italy” neo-natal incu-

bators which have always been distinguished by their original technical solutions and up-to-date

performance.

The secret of these products depends, on one hand, on a close relationship with university scien-

tific research, and a constant search for simple and new technological solutions and, on the other

hand, on the awareness that medical equipment, besides assisting the patient in the best possible

way, should make life easier for the medical staff rather than making it difficult.

This guide-book, the outcome of long experience, summarises clearly and in a few lines the evo-

lution of clinical incubators through the years, depicts “the state of the art” in this field and states

the indispensable technical requirements which neo-natal incubators should comply with in the

year 2000. I must express my appreciation of the “stubborn” dedication of Mr. Ginevri in the

world of neonatology and congratulate him on this scientifically flawless ad accessible guide-

book.


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Fundamental Characteristics

he Incubator is an apparatus researched, designed and constructed to create and maintain

an ideal “micro-climate” for the needs of newborns who are pre-mature and also to al-

low easy access for a complete range of medical assistance procedures .

The Incubator is different from a “Thermo-static crib” because the circulation of air, in-

side the patient dome, is forced by means of an electric ventilator.

Knowing that a baby in an incubator, breathing, produces 36 ml / min and the concentra-

tion of CO2 of that gas in the air we breathe, is one per thousand, the incubator should re-

new (36 l / min 1) to have a such concentration. Not more of this because “hyper ventila-

tion”, not only predisposes the newborn to heat loss (especially through evaporation) and in-

creases the internal noise level, but, when the doors must be opened (even one), it raises the

risk of contamination because the built in safety features of the apparatus are diminished

(for example: the micro-filtering of the air).

Taking into consideration the above mentioned, the principle characteristics to which an incubator

must correspond are:

• Careful choice of the construction materials;

• Manufacture of various components in one only piece die casting / injection

• Simple assembly and dismantling of the components;

• Even thermo-regulation of the circulated air;

• Noise level kept to less <45 db);

• Maximum thermal isolation;

• Equipment for humidification of the micro-climate;

• Unbreakable, fire retardant, washable, non-conductive for electricity, maximum isolation of the internal

noise level, not sensitive to normal disinfectants, nor in general to oils, fats, and diluted acids;

• Optimum visibility from both inside and outside the hood;

• Possibility to allow the little patient to participate in the sounds around him (including his Mamma’s

voice).

• Air exchange 36 L / min

• Maximum visibility and accessibility to the patient even for surgical procedures, X-rays, to reanimation

and continuous ventilation, to posturing to photo-therapy, weighing, and to connection to various other

apparatus - monitoring, etc...

• Inter-changeability of all components and all accessories (necessary for the various types of therapy).

• The capacity to maintain, with pre-selected values and for the time necessary, the body temperature of

the little patient even when the doors must be opened.

T


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• The hood must be spacious, particularly for height, to allow for ample manoeuvrability by the operators

both with the bed level and with the little posture bed incorporated and must be capable of being com-

pletely opened, with the doors completely opened to “total light” from both sides, even both at the same

time.

• For medical assistance routines it must have 6 portholes (two for each long side and one for each short

side). The hinges for the doors must be the sliding hinge type, in one single piece and without fixing

screws.

• Door opening must be made possible both upwards and downwards on both the long sides, again simul-

taneously. To avoid cross infection upwards opening is recommended.

• With the doors opened to totally to “full light”, the visibility of the interior must stay unblocked and the

top of the incubator hood must remain free and accessible.

• The hood must also allow for the passage and anchoring of the tubes and wires necessary for connection

to a respirator, infusion pump, drainage, and the monitoring apparatus.

• Easy to dismantle control panel both for cleaning and disinfection as well as for technical repairs and of

complete substitution(inter-changeability).

• Easy to use control panel with digital and contemporaneous monitoring of the various parameters pre-

selected and in action.

• Micro-processor management.

• "Soft touch" buttons - "Key" button.

• Proportional heating with monitoring of the percentage of the heated used, with the possibility to con-

nect to the “data net”.

• Command panel which is water-proof and completely smooth.


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Choice of materials The choice of the construction materials for an incubator is of fundamental importance. In fact, the follow-

ing aspects depend upon this choice:

• How it functions;

• Its practical qualities;

• Disinfection;

• Estetics;

• Durability and resistance.

Every component of the incubator has a specific function, and the more the material used in its construc-

tion is technologically adapted for that use, the better its output will be.

Following this rule it will, therefore, be very easy to assess the conformity of the entire machine to the per-

formance and services which it will have to carry out.

Recent studies recommend that metal be avoided. Metal, in fact, even if treated using modern methods can

lose not only its integrity with time, but the magnetic field which is formed can create disturbances to the

various therapy and monitoring apparatus. In addition, the latest studies, now being carried out, have

shown that it can possibly cause disturbances which then manifest, over time, in the patients who have

passed long periods in incubators.

Therefore, now that “noble” types of plastics are available it is good practice to make use of these materi-

als.

POLYCARBONATE, for example "LEXAN", turns out to be very adapted to

this use because of its properties: non-toxic – unbreakable- fire retardant –

noise absorbent – heat resistant – water repellent – non- sensitive to oils, fats,

diluted acids or normal disinfectants..

POLYCARBONATE can be commonly used to manufacture “components” like:

baby feeling bottles, breast pumps, etc. It can be stamped out perfectly transpar-

ent and in different colours using a pressure fusion process.


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Function The practical aspects and function of an incubator is achieved when all the procedures needed to be carried

out by the newborn carer’s, from cleaning and disinfection after use to technical repairs, are made a self-

evident, practical and simple to carry out.

The wires for connecting the various functions (also optional functions) to the control panel must be con-

nected by use of non-interchangeable plugs.

The ability to completely disengage the incubator from the various electrical connections in an intuitive,

self-evident, practical and simple way permits staff, also non- specialist personnel, to completely dismantle

the apparatus in just a few minutes without the use of tools.

The components must be unbreakable, washable (for example with a hand cloth), able to be safely disin-

fected, totally resistant to changing shape and unalterable.

In addition, the pressure mould stamping process used adds to the component’s robustness, harmony

of shape and the duplicability of the components themselves which can, therefore, be substituted eas-

ily and without need for adjustment. Another advantage of pressure mould stamping is the ability to

manufacture components with rounded corners which improve air circulation, reduce internal noise

and guarantee complete sanitization because of the absence of inaccessible or difficult to reach angles

and corners.

ALL THESE FACTORS BECAUSE AFTER USE, EVEN WITH AN INFECTIOUS NEWBORN INSIDE, THE

APPARATUS CAN BE RE-USED WITH MAXIMUM GUARANTEE OF STERILITY.


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Good working order A good working order occurs when the air flow enter in and leave out the bell with a low regular and non-swirling flow in the path from the input to the output section. An optimal solution, scientifically proven, is adopted in our incubators where the air enters and exits the bell through eyelet spars developed along the perimeter of the base (around the tray pa-tient). This allows, together with the aerodynamic design of the bell, to obtain different advantages, in-cluding: the decrease in flow velocity, the decrease in noise inside, the decrease of contamination, uniform heating and humidifying of the newborn, the certainty of elimination of co2 produced by the newborn. We don’t have a scientific evidence indicating this optimal operation in incubators with the dou-ble bell. THE AIR SHALL ENTER PASSENGER COMPARTMENT "SLIP" ALONG THE FOUR INNER SIDES OF THE BELL TO CREATE AROUND THE NEWBORN, A QUIET AND UNIFORM DISTRIBUTION OF MICRO-CLIMATE THAT PERMIT THE HEATING AND HUMIDIFICATION OF THE SMALL PATIENT HOW PURE THE REMOVAL OF CO2 PRODUCED BY THE SAME. The studies, new materials and advanced technologies have allowed ginevri to realize its incuba-tor with these benefits, then, very valid:

- the system of air circulation is less constrained; - the aerodynamic shape of the bell; - the material used is polycarbonate; - the various components are printed in die / injection.


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Air flow in the bell without the double wall. (high velocity and turbulence)

Air flow in the bell with double radiant partition wall. (precarious both humidification and CO2 exchange)

Air flow in the bell without the double wall of Ginevri incuba-tors. (top shape)


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UNIVERSITY OF CAGLIARI

MECHANICAL ENGINEERING

EXTRACT REPORT OF GINEVRI’S INCUBATOR FUNCTIONALITY


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1. System Analysis

The analysis of Ginevri’s incubator was accomplished by decomposing the thermoregulation

system of its basic components, listed below:

• Filter air inlet

• Motor and blower

• Resistance heating

• Passage of air ducts

• Thermostatic System

• Cap

2. Electromagnetic Compatibility

It was used a measuring system provided by the Department of Electrical and Electronics Engineering for

measurements of the electric and magnetic fields.

The measured values are within the rules. We believe may be considerably reduced with appro-

priate shielding already being implementation.

3. Acoustic Analysis

Results show that the environment inside the incubator is home to acoustic intensity when sounds

are generated internally and externally (the crying baby, business department). The nature of the

reflecting surface of the cap (even if double) has very low coefficients absorption of sound en-

ergy. Unfortunately, this condition can not be changed because the cap (bell) must preserve the

characteristics of transparency, easy to clean, simple geometry. Therefore, we have designed and

implemented a system that allows you to play, inside the bell, songs and background music,

Mother's voice and other sounds, all pleasing to listening, creating a calming effect up to the in-

fant.

4. Analysis of aerodynamic field

The tests carried out were based on the finite element method using the package ANSYS /

FLOTRAN.

The program solves, at the same step, the aerodynamic problem with the determination of the ve-

locity and thermal fields making use of law equations of gas, in this particular case the air. It is

obtained, so, a full information on the conditions of indoor climate and on the flow velocity near

the position occupied by the baby. The climate control of Ginevri’s incubator we analyzed, is im-

plemented by finned electrical resistance, which is crossed by the air flow produced by an axial


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fan. In the suction room of fan, you create a vacuum which tends to draw air from outside through

a filter. The hot air is blown by series of small grooves on the periphery of the tray support of the

couch and sucked in correspondence of other jets. The total area of input is equal to about 4 times

the area of the exit ports. The speed of the incoming air is, therefore, very low, the magnitude is

0.3 m / sec. Field shape is well represented in Figures 11/12. In the next volume of the space oc-

cupied by the baby, the speed air is rather low and does not give rise to phenomena of noise.

Fig.11: Air Velocity field shape inside the shell

Fig.12: Velocity field related to a median cross section of the shell

5. Thermal analysis

The results obtained are well represented in Figures 13 and 14, and show the trajectories of some

particles from entering section to the outflow. Examination of the trajectories of individual air

particles shows a steady and no vortex flow in the path from input section to output. The analysis

of the velocity air field near the volume occupied by the infant, shows the average values in the

order of 0.0133 m/sec. And maximum values around 0.1113 mt/sec. As was already said the ve-

locity field is regular and uniform; it not exist concerns about compliance with legislation. In


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Figures 15 and 16 is represented the temperature range for two middle sections, longitudinal and

transverse, respectively, while in Fig. 17, it is represented the field temperature of a horizontal

section mail to a height of 0.1 meters from the plane containing the mat and 5-point temperature

sensing, on the mat itself, wich showed a difference (∆T) of 0.5 °C compared to that point (0.1 m)

allowed from legislation.


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Fig. 13: Speed and evolution of some fluid particles Fig. 14: Temperature and evolution of some fluid particles

Fig. 15: Temperature range in a median longitudinal section Fig. 16: Temperature range in a median trasversal section

Fig. 17: Temperature field in a section at a height of 0.1 meters from the floor


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CONCLUSIONS

The work has revealed interesting results for each of the issues analyzed. As for noise problems

various simulations have conducted highlighted how the cap and the volume inside is essentially a

cavity insulated with strong intensity attenuation for sounds coming from the external and multi-

ple reflections to the sounds generated internally. The infant is therefore subjected to high pres-

sure values for these acoustic sounds while receiving, strongly attenuated, the sounds outside.

This involves an isolation of the child outside world, especially when this is represented by

sounds pleasant and familiar. We applied, with encouraging results on the incubator under consid-

eration, a system of setting welcome sound that is generated within termoculla. Development this

system we hope will be the subject of our future cooperation. In this context we also studied the

implementation of a system for eliminating active sounds unpleasant and unwanted. The aerody-

namic analysis has shown that the air velocity field inside the incubator has values prevailing me-

dium-low and is very regular. Therefore, there are concerns relating to any possible disturbance to

the baby. Since the section of air passage entrant in the volume inside the shell is relatively large

compared to that of exit, relationship between the two sections is about 4, we have velocity input

rather modest corresponding to a laminar flow with a slow and regular air hot. The air accelerates

only, as was evidenced in the views submitted, in the vicinity of the jets out in a limited volume,

external to that occupied by newborn. The very low values of velocity mean that it sells, without

turbulence, significant amounts of heat during its path in the internal volume of the dome. The

temperature field is smooth near the volume occupied by the baby as well, sufficient, is the wash-

ing of CO2. We should also note that the indoor air quality is related to the placing of fresh air

through a light and a next to the filter intake area of the fan. The quantity of fresh air is, therefore,

related to operating conditions of the fan and the degree of cleanliness of the filter aspiration. Sys-

tems have been realized with a cavity (double bell) to make independent of each other parts and

systems for recycling air in order to optimize and dedicate the internal flow to wash only CO2

but, still, there is no scientific documentation on the question.


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NOISE 10dB RUSTLING OF LEAVES

20dB WHISPER

QUIET 30dB COUNTRY ROAD

40dB LIBRARY, PAPER RUSTLING

50dB HOUSES, SHOPS

THRESHHOLD OF DISCOMFORT 60dB CONVERSATION OUT LOAD, RADIO

70dB TELEPHONE, RADIO AND TV AT HIGH VOLUME

80dB ALARM, DANCE PARTY

RISK OF HEARING LOSS 90dB INTENSE TRAFFIC

100dB TRUCKS, BUILDING SITES, TRAINS, THUNDER

110dB ROCK CONCERT, UNDERGROUND, WORKSHOP

120dB SIRENS, PNEUMATIC DRILL

PAIN AND SERIOUS DAMAGE 130dB CANNON

TO HEARING 140 - 150dB JET FLYING PAST

160 - 170dB MACHINEGUN

180dB MISSILE, INDUSTRIAL FORGE


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Standard Humidifier For effective functioning of the neonatal incubator a

micro-filtering system of air and oxygen must be

present.

The humidification system must be easy to control,

regulate, dismantle and disinfect. The control panel

and controls must be naturally intuitive and easy to

manipulate.

All procedures necessary for the neonate’s care must be able to be carried out.

Servo-control and monitoring of the air temperature inside the hood, the skin temperature(also pe-

ripheral temperature), the oxygen concentration inside the hood, the oxygen saturation in the

blood, the humidity, the weight and also naturally the ability to connect the little patient to other

apparatus (respirators, etc.) are all very useful and important functions to maximize the care for

the newborn, also those in serious condition.

Today with electronic micro-components it is possible to integrate many functions into the incu-

bator’s control panel always remembering, however, that the incubator needs to be able to be eas-

ily and quickly dismantled to permit thorough cleaning and sanitizing of all the components.

The newborn’s care must be total, safe, and comfortable both for the patient and for the operators as it must also be possible for more than one person to treat the patient at the same time. When re-quired, for example when manoeuvrability through the portholes is difficult, it must be designed to facilitate the complete opening of the hood on both the long sides.


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Opening the doors The door opening possibilities are:

• Downwards; • Upwards; • Upwards and Downwards.

Opening Downwards − Safety devices are necessary (usually two to be manipulated one at a time) to avoid accidental (falling)

opening of the door; − Cross infections are possible because of the inevitable contact of the internal wall of the door with the

operator’s jacket or blouse; − The top of the hood stays free for the eventual need to rest apparatus, including photo-therapy lamps. Opening Upwards − Safety devices are not necessary against accidental opening of the door as this safety feature is inher-

ent and automatic when the door itself is closed ( the seating of the door itself prevents accidental opening);

− The door when opened and turned upwards rests on the hood wall at an angle less than 40° which prevents it being accidentally closed.

− Cross infection by contact is not possible. − The top of the hood remains free and unencumbered for the possible

need to rest apparatus, including photo-therapy lamps. Opening upwards and downwards − The best solution as it permits opening according to the needs of each particular situation.

38°


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Maintaining the Incubator internal heat level with the Doors Open

Given that when the doors are opened there is an inevitable alteration to the micro-climate, in order to maintain it unaltered, the incubator must have warm air circulating so that it enters into the patient space passing through slits situated around the patient tray, from bottom upwards. In such a way that a barrier of warm air is created which helps to maintain the little patient’s temperature when it is necessary to completely open the hood doors. For prolonged opening, and to diminish the heating time for a

neonate with serious h

pothermia, a supplementary static heat source is recommended: using an AQUAGEL thermal mat-

tress or a small suspended INFRA-RED RADIANT HEATER directed onto the patient.

We have recommended static because the systems involved with part of the hot air circulating around the neonate to compensate for the inevitable lowering of the internal hood temperature with the doors open are to be avoided for various reasons: • the air directed onto the newborn is no longer micro-filtered; • this ventilation accentuates liquid loss (phon effect) • can cause burning due to the raised air temperature level which

is much more marked when there is a great loss of heat from the hood

While these static sources are preferred: • AQUAGEL soft, impermeable mattress; • HOT SPOT infra-red suspended heater.

The first, AQUAGEL, because it has the capacity to store heat and to then give it to the little patient while the incubator is open for the normal routine (it can also be heat and servo-controlled by the patient); The second, HOT SPOT, because being a supplementary Infra-red sus-pended source of radiant heat servo-controlled from the patient, it facili-tates the maintenance of the patient’s temperature – keeping it rigorously constant for long periods with both the doors completely open. This heating system can also be used, with great success, with hypo-thermic newborns to reduce the body reheating time, with respect to that necessary when the reheat-ing is dependant solely on hot air (max 39°C ) circulating inside the hood. And at last because, with both systems: • Eliminate both hyperventilation and contamination; • Reduce, considerable, the loss of liquids due to evaporation

(*) It has been noted that with respect to acrylic (Plexiglas) hoods that require a double wall, the polycarbonate pressure fused

hoods have less heat dispersion and therefore does not require a double walled hood and they also have a smaller ∆ between the

heat source and the hood. .

Opening and closing the porthole access must be able to be done with a simple mechanism activated by a

small pressure.


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The possibility to “position” the newborn in the Trendelemburg and Fowler must be “soft and grad-

ual” and, when taking the patient tray out of the hood, it must guarantee the stability of the patient tray it-

self.

The Incubator must be mounted on a trolley equipped with, in addition to perimeter protection handles,

rubber rollers of a reasonable diameter and smooth action (two with brakes). The possibility to vary, by

way of foot controls, the height of the working level of the incubator between approximately 60.5cm and

80.5cm; fixed is at approximately 71cm).

Support surface, set of drawers, IV pole support and for assistance apparatus and monitoring must be

available and easy to use..


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Criterion for the choice of Incubator type The choice of an incubator should be made in relation to the level of neonatal assistance for which it is des-tined to be used:

• MINIMUM THERAPY - SUB-INTENSIVE

• INTENSIVE THERAPY/SURGURY

• SUPER-INTENSIVE THERAPY/SURGURY

This requirement is made simple and practical by those manufacturers that, whilst still keeping all the fun-

damental characteristics for an incubator already mentioned in place, design the

INTERCHANGABILITY OF THE CONTROL PANEL to offer different operational characteris-

tics: therefore using the same outside measurements, and having the following performance charac-

teristics:

• Servo-control and monitoring of the Air and Skin temperature values (Air and Skin Mode).

• Servo-control of the Air and Skin temperature (also peripheral) with monitoring of those same

values and of the humidity percentage, oxygen concentration inside the hood or head box micro-

climate.

• Servo-control of the Air and Skin temperature (also peripheral), of the humidity level and the

oxygen concentration inside the hood and the head box micro-climate.

• Servo control of the Air and Skin temperature (also peripheral), of the humidity level, oxygen

concentration inside the hood or head box micro-climate, of the oxygen saturation in the blood

and the weight – all visible on a LCD monitor in digital mode with graphs showing the relative

trends.

This capability permits the passage from super intensive care to intensive care and then to sub-intensive

care and less by only changing the control panel without having to move the little patient from the incuba-

tor which first welcomed him, thereby avoiding the traumas and risks of contamination.

Also from the economic point of view it an excellent solution when you take into consideration the cost of

a control panel compared to the cost of an entire Intensive care/Surgical incubator.


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Digital data screen Menu Screen Temperature trend screen


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Humidification System Considerations

With the Humidification inside an incubator a very important factor, even if the humidity is generated by

system which produces “Truly Sterile” humidity, that is to say in which the water has not had any con-

tact with the interior of the incubator. To achieve this

objective the water must be taken from an external con-

tainer using a measuring system with a peristaltic pump

managed by a micro-processor sensitive to the selected

humidity level which allows the water to fall, drop by drop,

onto an evaporation plate heated to 135°C. It must all be

isolated from the patient environment in such a way that

inside the hood only vapour will enter and diffuse (SERVO

STEAM).

N.B.

• The Evaporator (1) and the peristaltic pump (2), are

located in a specially designed space inside the incuba-

tor base, they are completely isolated from the patient

cockpit; but can be easily inspected from the outside;

• The Water container (3), is located outside the incubator in the provided holder “anchored” to the

trolley and easily taken off for cleaning, re-filling, etc.

Instead, servo-controlled humidification systems in which the hot air, destined for humidifying the pa-

tient cockpit, touches the water contained in reservoir, can in this way achieve the desired level of

humidity, but CANNOT GUARANTEE the sterility of the humidity even if the container has been

filled with sterile water.

HUMIDIFIED AIR STERILE

EXTERNAL AIR MICRO

(1) EVAPORATOR (2) PERISTALTIC PUMP (3) WATER CONTAINER

HOOD


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Comparision between Incubator Hoods made of Acrylic and Polycarbonate (LEXAN) HOOD IN ACRYLIC (Plexiglas/Perspex) Inflammable not self-extinguishing Deforms due to heat at: 80°C Hygroscopic Subject to micro-cracking with possibility of microbes at-taching and difficulty with disinfection also because the parts are glued. Not resistant to impacts and bangs. Delicate to external agents and cleaning materials. Traditional hinges which do not allow for easy dismantling nor safe disinfection. Noise on opening the doors with traditional hinges: In the norm considering the only function which it has, i.e. The opening of the door. Critical of the dismantling for cleaning/(sterilization. Limited barrier to heat loss: need to use a double hood Heavy and sensitive to all cleaning and disinfection proce-dures. Useful space: generally fairly limited – particularly the height – which does not allow for easy manoeuvrability to carry out care routines, in particular in intensive therapy and surgical procedures.

HOOD IN POLYCARBONATE (Lexan) Non inflammable and self-extinguishing. Deforms due to heat at: 180°C. Not hygroscopic. Not Subject to micro-cracking. Completely smooth because it is stamped out in pressure fusion in one single piece. Unbreakable. Non-toxic, not attackable by oils, fats, or to normal disin-fectants. Special hinges which permit easy and rapid dismantling and a safe and total disinfection. Noise on opening the doors: less than the norm because of hinges are made with silicon which is silent with the fol-lowing possibilities:

• Open upwards (retractable door); • Open downards (door hinged down). • Everything to facilitate easy dismantling for

cleaning and sterilization. Insulating due to the compact molecular structure of the polycarbonate material. Light, easily manageable even when taking into considera-tion its unbreakable nature. Possibility of thorough clea-ning and disinfection., Useful space: not limited to permit maximum manoeuvra-bility in all types of care including surgical and making these procedures comfortable both from the open porthole doors, even simultaneously, and also gives the possibility to have supplementary radiant heating for operations which require the porthole doors to be open for long periods of time.

Characteristics of “LEXAN” polycarbonate As is shown above the superiority of pressure fusion stamped Polycarbonate with respect to Acrylic (plexiglas, etc…) with glued walls.

In sunlight it is 111°C and the shade it is -193°C. Micro-particles are hitting you at a velocity

of more than 75,000 km per hour. There is no air….. Would you take a work without

the protection of LEXAN in your helmet?

L E X A N One of the hardest polycarbonate resins in the world

There, outside in space, there is no second chance.

And this is why NASA has chosen GE Plastics’ LEXAN for the face plates in their helmets for the

NASA space walks.

Lexan is not only one of the hardest polycarbonate resins in the world, but it possible to select dif-

ferent grades which offer the clearest view of the supreme vista, a decisive advantage if you find

yourself face to face with the highest challenge.

Also on land LEXAN is taking technology to new limits. Its great transparency, unequalled resis-

tance to impacts, high thermal resistance, self-extinguishing properties, exceptional dimensional

stability, the high grade of flow during the stamping process, the wide range of colours available,

offers to producers of the most diverse sectors – hospitals, houses, schools, offices…. – great advan-

tages in focusing on new boundaries and limits - as if one could wait for a new material made to

safely take man to the farthest destinations and back.

. . . and it is out of pressure fusion LEXAN that all the Ginevri Incubators are manufactured!!!


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Considerations about the Usefulness of a Double Hood From the time when incubators came into use, the authorities and specialists in neonatology have been doing continuously improving through research and development of the incubator in order to find and provide the very best care for premature newborns. In order for the circulation of forced air inside the patient cockpit space to be most effective it must be homogenous in order to obtain the micro-climate necessary for the little patient. This premise has for many years been the “goal” to overcome for manufacturers that they could then con-firm to be the only one. There were many constructive attempts carried out by the manufacturers to obtain that homogeneity; but all failed until, in the period 1960 -1965, one manufacturer thought to install a second hood in such a way to achieve an airspace in which to pass the hot air. This did not form the harmful turbulence and heated the patient cockpit by radiating the heat from the second hood. Although this “solution” was appreciated and adopted by all the manufacturers which in the meantime had “flowered” copying the original manufacturer, other studies started to demonstrate that that sys-tem had some problems:

• Greater heating of the air to send into the inter wall airspace which leads to a much higher tem-perature under the patient cockpit (that means under the patient), a temperature much higher than that necessary for the patient, therefore dangerous for both burns and for the high concentra-tions of oxygen often necessarily circulating inside the hood.

• Limited useful space for the carers and medics; • Change of the internal hood air, critical; • More noise both because of the need to increase the forced hot air circulating in the inter wall

space and because the path of that air is angular; • Higher consumption of energy, oxygen and everything else necessary for the ideal micro-climate

for the little patient; • Difficult to clean and sterilize.

ARIA CALDA ARIA CALDA

Single hood Double hood

WARM AIR

WARM AIR


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So commenced the study of incubators without a double hoods.

New materials and advanced technologies permitted the realization of an extremely effective incubator:

The air circulation system is less restricted; The hood shape is aerodynamic; The material used is polycarbonate; The various component parts are pressure fusion stamped.

In fact with such materials the following characteristics are achieved: The hot air flows into the patient cockpit slipping along the whole surface of the hood’s interior walls them-selves at low speed, uniformly warming the patient cockpit and the little patient the “delta” between the air temperature entering and that diffused inside the patient cockpit is minimal as is the loss of heat to the out-side because polycarbonate is extremely resistant to heat ( the pressure fusion process works at approx. 300°C while Plexiglas and similar products work at approx. only 80°C).

If you add to the above the study carried out years ago (published in Paediatrics) which demonstrates how efficient a little HEAD BOX placed above the newborn is for considerably diminishing the little patient’s heat loss and thus unequivocally demonstrates, the inefficiency of the double hood. ROOM TEMPERATURE 25°C – 27°C

INCUBATOR WITH DOUBLE INCUBATOR WITH INCUBATOR WITH WALL CONVENTIONAL HOOD CONVENTIONAL HOOD AND

MICRO-CLIMATE HEADBOX

Temp. 35°C o più Temp. 30°C Temp. 30°C

Temp. 30°C LEAK FOR:

NEGLIGIBLE RISES WITH INCUBATOR OPEN MINOR THAN FOR A STANDARD INCUBATOR HIGH

CONDUCTION CONVECTON RADIATION EVAPORATION

NEGLIGIBLE RISES WITH INCUBATOR OPEN IN RAPPORT WITH THE ROOM TEMPERATURE ALTA

NEGLIGIBLE DOES NOT RISE AUMENTA WITH INCUBATOR OPEN MINORE THAN FOR A STANDARD INCUBATOR WITH DOUBLE WALL INCUBATOR NEGLIGIBLE


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HEAD BOX MICRO-CLIMATE

Useful to create a micro-climate for very low weight newborns in an Incuba-tor, by means of a closed tent around the body. The newborn in the Incubator heat dis-persion occurs in four ways: - conduction (loss of heat to the mat-

tress where in contact with the body); - convection (loss of heat to the air cir-

culating around the body and which is continuously carried away with the forced air circulation);

- radiation (emission of radiant heat towards the surrounding environ-ment);

- evaporation ( heat loss associated with the imperceptible water loss).

With the newborn in an incubator the loss due to conduction is negligible and loss by convection is minimized by the fact that the air coming into the incuba-tor has a temperature very near to body temperature. However, the loss due to radiation and evaporation can be signi-ficant. The heat loss due to radiation is due to the fact that the baby‘s skin being hotter than the incubator walls, the quantity of radiant heat which goes from the baby’s skin to the Incubator wall is greater than that which goes from the walls to the baby. This loss is not influenced by ei-ther the temperature nor the humidity of the air inside the Incubator (which only change losses due to convection and evaporation), and the loss is greater the colder the external Incubator walls are (and therefore also depends on the room temperature).

Heat loss due to evaporation is greater as the Incubator’s internal relative hu-midity is lower (because evaporation is much greater the more the drier the am-bient air). And the more premature the baby is (due to the thinness of the horny layer).

This carries a loss of not only heat but also water, which can be enormous: in fact, premature babies of 26 or 27 weeks have been measured to have lost water up to 100ml/kg/day if the relative humidity is 30%. To eliminate the loss due to radiation, Incubators have been manufactured with double walls to minimize this loss because the inner wall has a temperature very similar to the that of the baby’s skin. In any case these incubators (apart from the prob-lems of cost, maintenance and accessi-bility which they bring) do not resolve the problem of heat loss (and water) due to evaporation which represent the prin-ciple loss of heat for very premature newborns. This loss, already substantial in stable ambient conditions, (where the relative humidity does not go over 40-50%, while it must ideally be not less than 60%), is still further worsened by opening of the access portholes and doors frequently practiced per the many indispensable care and medical assis-tance procedures necessary: it can, in fact, be documented by using the con-tinuous recordings which show that with the opening of the porthole doors, even for just a few seconds, results in a per-ceptible reduction in both relative hu-midity(and therefore increases the loss due to evaporation) and the temperature ( and therefore an increase in the con-vective heat loss), and that the return to the starting levels can also be surpris-ingly long. The loss from both radiation and evaporation(and also the convection heat loss due to the incubator being opened) would have to be gradually re-duced through the simple practice of covering the newborn head with a transparent plastic box closed at the col-lar. This “head box” minimizes the ra-diation heat loss because, being the same temperature as the circulating air, it has a very low thermal gradient with

respect to the baby’s skin temperature and thus reproducing the same situation found when using the double wall sys-tem. At the same time minimizing the evaporation losses as a micro-climate will be very quickly created from the baby’s slight perspiration (resulting that the water vapour produced by the baby’s skin is no longer taken away by the forced air circulation inside the in-cubator, as happens in the absence of the head box). Finally, the convection and evaporation heat losses resulting from the incubator being opened are minimized as the mi-cro-climate around the head remains much more stable. Preliminary experi-ments have demonstrated that, with the head box: - when the Incubator’s relative humid-

ity is at standard operating levels from 40-45%, the relative humidity of the head box reaches levels around 70%;

- when the baby, previously in standard conditions and with servo-control, is placed under the head box, the body temperature reduces by 1°C-2°C;

- the micro-climate under the head box does not appreciably change when the porthole doors are opened for normal care procedures. These preliminary observations suggest that the head box is a more efficient than the double wall incubator for reducing the loss of body heat, water and the consumption of oxygen. Other advantages are:

- low cost; - flexibility of use, as the head box can

be put on or taken away according to the needs at that time.

- Raised relative humidity only where it is useful and reducing, therefore the risk of bacteriological multiplication and spreading.


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Heating with a Hot Air Barrier across an open doorway

Hot Air BarrierIncubators

JOEL ANCELLIN, ENGINEER Potiers Hospital Centre of Biomedical Engineering

Ingegneria Biomedica del Centro Ospedaliero di Poitiers (Francia)

Technical Service of Clinical VigilanceServizio Tecnico di Vigilanza Clinica


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Joel Ancellin, Engineer Biomedical Engineering of the Hospital Centre

di Poitiers – France – Le Banc D’Essais – La Materiovigilance (Material Vigilance) - pg. 5 – 17


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(Translation of the text in French above)

Two new cases of burning to newborns have happened and have required the partial amputation of the fingers of newborns. The circumstances of the supervision of both of these cases is similar and, therefore, it can be concluded that the re-sponsibility for this could be due to the type of heating. Le us remember that incubators with a curtain of crossing hot air have been made and, therefore, distributed for more than 10 years in the French market (Airsheilds, Dragar, Ohmeda, etc). In this type of apparatus the heating of the patient cockpit arrives through an air conduit which allows the circulation of the air across two side bottle (one entry and one exit). Give that to carry out various operations on the newborn (for example to place an umbilical catheter) the opening of the access ports are not enough for the operator and consequently it is necessary to open, at the very least, one side door of the incubator, naturally as a consequence the temperature inside the hood and of the newborn both must de-crease and therefore a supplementary source of heating becomes indispensable in order to maintain the little pa-tient’s temperature to the levels reached when the incubator is closed. To get this result one can choose to transport the newborn from a traditional incubator to a topless incubator (Infant Resuscitation Table), but obviously, this car-ries other risks due to the trauma of being moved, especially for intubated infants. Therefore, the cases mentioned above thought, to avoid the inconvenient and risk of the lowering of the newborn’s temperature, to deviate a part of the hot air flow, meant to heat the entire patient cockpit, onto the newborn. This has caused the above incidents. In fact, the temperature of the hot air exiting the deviation device, easily went over 50°C. In both the cases, the babies’ organs, exposed for the time necessary to carry out the operation to this exces-sive temperature, received irreversible burns. A notice of 2 August1995 (ref. 95-3136) had already brought an identical incident to the awareness of the compe-tent authorities, but being unique, this was considered an individual accidental case. However, in light of the facts above, today this could not have been more confirmed. The manufacturers defend themselves by attributing the blame to misuse of the apparatus itself by the operators, as the injuries could have been caused because the patient or part of the patient could have been placed in contact with the heating unit outlet of this hot air current. So, not only, does this go against the most simple operating conditions on the part of the extremely expert newborn carers, but it must also be considered as an important defect of the in-cubator. In conclusion, at the moment, it is necessary to look into, with great care and attention into these possible inci-dents. As it also counselled to recommend to the manufacturers to put-off the manufacture of this type of solution (hot air across the baby). Better still, at the moment, it would be better to not use this type of heating in the incubators, or transfer the new-born to an open topped incubator (Infant Resuscitation Table) which will be put, as a preventative measure, near the intensive care incubator.

Joel Ancellin, Engineer

Biomedical Engineering of the Hospital Centre di Poitiers – France –

Le Banc D’Essais – La Materiovigilance (Material Vigilance) - pg. 5 – 17


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Technical Report on Ginevri Incubators

TECHNICAL REPORT ON THE

GINEVRI

INCUBATORS

Compiled by: GG MOUTON from Dept. Clinical Engineering


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TYGERBERG HOSPITAL (S. AFRICA) Department of Clinical Engineering Private Bag X5, Milton Road 117 Goodwood 7460

(traduzione del testo in inglese a fianco) DATE: 15/01/98 Incubators Utilized: Poly Care 2 The following results have come out during the tests: REPORT of TEMPERATURE TEST:

Ambient Temperature: 22°C Incubator Temperature set at: 34°C Time taken by the incubator to reach the set tempera-ture(34°C):

11 min.

Maximum range of temperature oscillation with respect to the set temperature (34°C):

33.9 Min. - 34.3 Max

Tolerance with respect to the set temperature (34°C): < 0.5°C

Temperature read by the thermostat when the display screen shows an effective of 34°C:

34.2°C

Noise level inside the hood 44 Db MEASUREMENT OF THE TEMPERATURE VARIATIONS WITH ONE OF THE TWO PORTHOLE DOORS

OPEN AND THE BED IN A RAISED POSITION

Incubator Temperature set at: 34°C Measurements taken at the patient’s bed level Time Interval Temperature

Fluctuations Thermometer reading

1 min. 33.5°C 33.0°C 2 min. 33.2°C 32.8°C 3 min. 33.0°C 32.5°C 4 min. 32.8°C 32.0°C 5 min. 32.9°C 32.0°C The temperature is stabilized after 5 min. and has commenced to rise after 7 min. 10 min. 33.4°C 32.3°C 15 min. 33.7°C 33.1°C 20 min. 33.9°C 33.2°C 25 min. 33.9°C 33.1°C 30 min. 34.1°C 33.4°C The air circulation inside the incubator is much higher that the standard required. The ease of circulation of the air was made possible by a well designed hood which produces an excellent thermal barrier to the hot air.


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MEASUREMENT OF THE TEMPERATURE VARIATIONS WITH BOTH THE PORTHOLE DOORS OPEN AND THE BED IN A RAISED

Incubator Temperature set at: 34°C Measurements taken at the patient’s bed level Time Intervals Temperature

Fluctuations Thermometer reading

1 min. 33.3°C 29.9°C 2 min. 33.1°C 29.7°C 3 min. 32.9°C 29.4°C 4 min. 32.6°C 29.1°C 5 min. 32.7°C 29.0°C The temperature stabilized after 4 min 35 sec and started to rise after 6 min. At a sudden change in the temperature an immediate corresponding activation fo the heater, at maximum power, creating an increase in the circulating hot air. This speed of response by the heater created a hot air barrier, perpendicular to the hood opening with the aim to limit the temperature lowering without creating turbulence around the patient inside the incubator hood. 10 min. 33.1°C 31.3°C 15 min. 33.4°C 31.4°C 20 min. 33.7°C 31.8°C 25 min. 33.9°C 32.7°C 30 min. 33.9°C 33.3°C I risultati ottenuti con l’incubatrice Poly Care 4 sono esattamente gli stessi di quelli rilevati per la Poly Care 2. Siamo molto soddisfatti per le prestazioni di questa linea di incubatrici, che si sono rilevate nella maggior parte dei casi di gran lunga superiori a quelle dell’incubatrice Isolette QT prodotta dalla società Air-Shields e tutto ciò rap-presenta un indiscutibile successo per la Ginevri. The optional accessories with are available with the Poly Care 4 Incubator are excellent. The Poly Care 4 Incubator allows and makes treatment for premature babies possible in all situations and ones at high risk where capillary checks and controls of the patient are necessary, an action to determine the ambient conditions suited to him, that is to be able to control the humidity and oxygen concentration, as well as the oxygen concentration supplied, without utilizing the add-on monitoring systems which could be used elsewhere. A Pulsometer is recommended every time the treatment requires oxygen to be administered. HOOD The hood is made of polycarbonate stamped in a single piece with a hot pressure fusion process. This material represents a phenomenal innovation with respect to traditional transparent Perspex, which easily cracks, breaks or distorts the view of the patient due to irregular curves in the surface. Pressure fusion in a single piece guarantees ex-treme durability and the absence of joints makes very thorough cleaning and sterilization extremely easy, the hood is also able to withstand heat up to 150°C, is not vulnerable to chemical agents and is not toxic, characteristics which make this incubator undoubtedly superior to all others on the market.


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BASE Also the base is made from polycarbonate pressure fused in on single piece, with smooth surfaces and rounded cor-ners both internally and externally. These characteristics allow for total cleaning and sterilization. The base consists of a patient tray, in a micro-filtered air system, a humidifier and two oxygen inlets. It is also fitted with a SMOOTH TILT mechanism for adjusting the bed inclination into Trendelemburg and Fowler, rotating the two handles, located on the right and left of the base, clockwise and anti-clockwise The patient tray can also hold the electronic BILLA weighing scales which consists of a control unit managed by a micro-processor, is a power unit and a weighing unit compatible with other incubators. The electronic BILLA scales have the advantage of making it possible to weigh the patient, during and after feeding and or administration of drugs without having to take the newborn out of the warm incubator environment.

OPTIONAL ACCESSORIES

X-ray Plate - the plate consists of a wide surface needed to carry out the X-ray exam. The

plate is easily inserted under the patient tray which has been placed in an ele-

vated position.

IV pole - consists of a stainless steel pole to support eventual monitoring systems and

IV bottles. The Incubator can be moved anywhere without disconnecting the

infusion setup.

Trolley - available in three versions: Standard Open Trolley with a shelf underneath,

Closed Trolley (optional), Height Adjustable Open Trolley (optional).

CONCLUSIONS

Ginevri has contributed greatly to the progress and development of the existing incubators. The use of Ginevri’s in-

cubators and their accessories allows for the total care and assistance to premature babies. The incubators have be

tested by Mr. J.C. Carstens of the Technical Department of the Tygerberg Hospital. Mr. Carstens and I agree on the

technical performances and the advantages deriving from using this product. We both sincerely recommend the pur-

chase of Ginevri incubators for all the Provincial hospitals.

G.G. Mouton J.C.C.Carstens J.N.van den Berg

Tech. Director Electronic Dept. Tech Director Anesthesia Dept. Tech.Director Re-animation Dept.

(Written and compiled by Mr. G.G. Mouton of the Clinical Engineering Department)


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