Infant Warmer-incubator

Abstract

An infant warmer-incubator constructed to provide a controlled air environment about the infant. The incubator maintains the proper environment in an "open" or "closed" position and will permit resuscitation, technical procedures, surgery or routine nursing care of the infant as with a crib or bassinet. In the "closed" position some nursing care may be performed while in the open position it may serve as an operating table and not materially disturb the controlled environment for the infant. The incubator control permits the premixing and careful measuring of a therapeutic gas, e.g., oxygen with air, and the humidification thereof, which mixture is delivered to the incubator to surround and maintain the infant in a preferred environment of warm, humidified and oxygen-abundant gases. This apparatus can be placed into operation very rapidly, within 3-5 minutes if needed for emergencies, e.g., deliveries of premature infants. It comprises a vaporizer having a small boiling chamber over which is drawn the therapeutic gas to be mixed with the vapor and discharged to the bottom shell of the incubator. From the bottom shell the mixture is distributed and is forced upward through a bed frame and around an infant. Continued movement carries the gases out the open top and the pressure inside avoids ambient room air from flowing down onto the infant.

Parent Case Text

RELATED CASES

This application is a continuation of application Ser. No. 111,305, now abandoned, filed Feb. 1, 1971 which is a continuation-in-part application of application Ser. No. 832,279, filed June 11, 1969.

Description

The present invention relates to an improved infant warmer-incubator utilizing a vaporizer and particularly to an improved incubator structure for premature infants where the environment must be carefully controlled and not altered when access to the infant is necessary for resuscitation, operations, X-ray studies or normal care of the infant in the incubator.

Improving incubators to protect premature infants against excessive heat loss is still a goal towards which much research is directed. Infant warmers utilized in delivery rooms have been designed to supply low energy radiant heat to an open-ended crib with a hood or an overhead canopy, which provides "deep heat" warmth to the top surface of the infant. Since part of the premature infant heat loss is by radiation, supplying warmth to the infant by radiant heat was considered the best course. This type of infant warmer supplies no humidity, and heats only one surface of the infant. It is also very uncomfortable and/or inconvenient for the technician to attend to the infant and still maintain the functions of the infant warmer. This type of warmer or incubator leaves much to be desired.

The presently known and now utilized infant warmers and incubators fail to meet the demand for careful treatment and care of the premature infant. There is not in existence a suitable incubator operating table or incubator X-ray table. There are prior known radiant heat type open bassinet infant warmers and examples of the enclosed type incubators are shown in U.S. Pat. Nos. 2,347,326; 2,624,333; 3,076,451; and 3,529,590.

The incubators now utilized in the hospital nurseries are typically a closed transparent container housing the infant for providing the infant with a controlled environment of a desired temperature and oxygen concentration, and to a lesser extent a desired humidity. This system requires very complicated and expensive oxygen mixing and dispensing valves and frequent oxygen concentration testing. They are relatively difficult to operate and maintain any constant conditions. Providing a desired relative humidity in a closed system is at best not well controlled and generally only haphazard. The most undesirable feature of the closed incubators is that it is difficult to provide nursing care, or other technical procedures on the baby and still maintain the proper environment in the incubator for the baby. Usually, the technician must put his hands through portholes in the container and work through the holes at great inconvenience to maintain the incubator environment for the infant. This makes surgical procedures next to impossible, especially if a sterile environment is to be maintained for surgical procedures.

To date, there is not an incubator operating table available to the medical profession. The procedure now used is to heat the whole operating room for premature infant surgery.

There is also no incubator X-ray table apparatus available to do X-ray studies on premature infants while maintaining it in its incubator environment. Lastly and most important, there is not an open bassinet-type infant warmer-incubator in existence which functions as an infant warmer-incubator and also provides ready access to the infant by nursing personnel and other technicians. There is not in existence a closed incubator system which accurately maintains an environment of desired temperature, humidity, and oxygen concentration since they require circulation and thus consistency is hard to achieve. There is not an apparatus presently available commercially which performs efficiently the function of an infant warmer, an incubator, an operating table, or an X-ray table, all in one single unit.

The transfer and handling of the premature infant from one environment and apparatus to another affords many hazards to its delicate and sensitive life-maintaining systems. Chilling, handling, the lack of or too much oxygen and improper humidty are often lethal to the premature infant. To a lesser extent crippling of the infant's vital systems may occur, such as the infant's respiratory system and central nervous system and cardiovascular system.

The humidity, temperature, nutrition and respiration are all maintained through the mother prior to birth. After birth the infant has to perform these functions on its own or have them performed by others for him. To lessen the shock to which he is subjected at birth due to the changes in temperature and humidity it is necessary to initially establish for premature infants an environment comparable to its previous maternal environment. It is also necessary to establish an initially satisfactory respiratory atmosphere for the infant. The initial minutes or seconds are of the utmost importance to restrict any respiratory damage to a new born infant. Providing the proper environment is especially important with premature infants who are not developed or prepared to make the physical changes that a full term baby is equipped and prepared to make at birth. This environment and atmosphere must be instantly available. It is dangerous to apply therapeutic gases, namely high concentrations of dry oxygen, to the premature lung tissues or to place the newborn in a lower temperature, unhumidified environment since the premature infant has left a warm wholly marine environment. The existing incubation equipment is not prepared to provide a comparable environment. The lack of such equipment is suspected to be a cause for premature infants developing Hyalin membrane disease and respiratory distress because the present equipment provides only radiant heat for the infant and it lacks any satisfactory temperature and humidity control for oxygen or ambient air for inhalation by the premature infant.

Hyalin membrane disease often results in a fatality, and always results in vastly expensive medical care once it has developed. Only infant lung tissue which has breathed or been exposed to environmental air through respiration has ever been found to have this disease. Upon autopsy of infants and premature infants who have expired, Hyalin disease has been observed only in lung parts expanded by performance of the respiratory function and has never been found in lung parts not yet expanded or utilized in performance of respiratory function. This is interesting because although there may be many predisposing maternal factors, plus defects in the new born infant's health, the air and added therapeutic gases, i.e., cold dry oxygen inhaled by the new born, either precipitates the disease or plays a large role in the progression of the disease.

Therefore, it stands to reason, the less "shock" which results after transferring the premature fetal lung from the maternal protective environment to a new postnatal air-land environment the less likelihood of Hyalin membrane disease to be percipitated. This shock can be reduced by immediate transfer of newborns to a controlled environment similar to that of its previous maternal environment immediately prior to the establishment of respiratory function by the newborn.

The apparatus of the present invention readily provides this controlled environment and atmosphere and should be available in the delivery room, operating room, and in the nursery for continued aftercare.

The ideal infant warmer-incubator and other apparatus utilized in maintaining the premature infant in a desired and controlled environment is one which provides all of the environmental functions available to the premature infant in the mother's womb, except those functions deleted by severance of the umbilical cord, namely, respiration and nutrition. These vital functions must be supplied by a controlled environment and by the helpful human hand. To provide these vital functions to the premature infant and still maintain it in an environment warm and moist like his maternal environment and yet make him readily and easily available for technician or nursing care, is the major advantage of the present invention.

Secondarily, the device of the present invention has the advantage of providing an operating table and an X-ray table with all of the convenience and utility necessary while retaining the function of an incubator for the premature baby.

In essence, the present invention will rapidly make available for the premature infant an environment which is its "mother's womb" than presently exists, but still make the infant available to perform vital functions which have been deleted by severance of the umbilical cord. The device of the present invention affords a means of performing technical procedures, diagnostic studies and general nursing care, in a sterile field, if necessary, without hindrance by cumbersome enclosing apparatus.

The infant warmer-incubator utilizes an improved vaporizer-humidifier which will readily provide mineral-free water vapor to be mixed with air or therapeutic gases. The gases withdraw the vapor rapidly enough to be discharged as super saturated ambient air or super cooled steam. This vaporizer affords a high relative humidity environment and one which is particularly high at normal body temperature.

SUMMARY OF THE INVENTION

The infant warmer-incubator of the present invention comprises a base member which will support a porous nonabsorbent soft sterile hammock-type bed for the infant and through which the environmental gases will be introduced to the infant. On top of the base is a hood which has an open upper aperture which is only slightly smaller in dimensions than the bed to permit easy access to the infant lying upon the hammock. The hammock is substantially level with the top of the base. The four sloping transparent sections which form the hood are hinged to a support frame and may be individually lowered as necessary when the medical nursing and/or surgical procedures are being performed. The base is provided at one end with an opening which will permit access at that end to the area beneath the hammock to change the urine tray, insert X-ray film cassettes etc., without removing the baby from the incubator. The controlled environment is supplied to the incubator through a vaporizer where the water vapors are mixed with ambient air and with therapeutic gases in measured quantities as desired. The environment can be maintained at a predetermined temperature and relative humidity or adjusted by proper controls of the quantity and the temperature of the ambient air drawn in, the amount of humidity, the amount of the therapeutic gas, and the temperature of the mixture directed into the incubator. The environment will be free of any minerals which may be present in the water (such as tap water) which is utilized for humidification, and there will be no danger of burns or of a clogging of the humidifier.

DESCRIPTION OF THE DRAWING

Referring now to the drawing there is illustrated in FIG. 1 an elevational view of the incubator formed in accordance with the present invention with parts in sections and including a schematic of the controls utilized for providing the desired environment;

FIG. 2 is a plan view of the incubator according to the present invention;

FIG. 3 is a fragmentary left end view of the incubator of the present invention;

FIG. 4 is a fragmentary right end view of the incubator;

FIG. 5 is a transverse sectional view taken along lines 5--5 of FIG. 2; and

FIG. 6 is a sectional view showing the bottom of the vaporization chamber of the humidifier as seen along lines 6--6 of FIG. 1.

Referring now to the drawing there is illustrated the infant warmer-incubator 11 comprising a base 12 and a hood 14. The base would typically be supported on a cabinet or wheeled frame which would support the electrical and mechanical hardware for providing the controlled environment within the wall of the incuabtor. The base 12 is provided with a centrally positioned depending plenum 15 beneath which is supported a vaporizer-humidifier 16 which discharges the warmed moist gas into the base under the force of a fan 17 forming a part of said vaporizer-humidifier 16. Certain control elements are connected to the vaporizer-humidifier 16 for regulating its operation to maintain the atmospheric conditions within the incubator at the desired level.

Referring now to the schematic portion of FIG. 1, the vaporizer-humidifier 16 comprises a reservoir formed by a shell 19 which may be generally circular in horizontal section and which is formed with an upper enlarged reservoir 24 and a reduced lower portion 20. The bottom of the shell or lower portion is conical or funnel-shaped to terminate in a reduced opening upon which is secured a flush valve or a removable cap to permit removal of the minerals collecting in the lower portion of the shell. The lower portion 20 is positioned to receive any minerals purged from the water as the same is changed to vapor in a vaporization chamber 21. The chamber 21 is defined by a cylindrical member positioned within the shell 19 and formed of an insulating material which for example may be a polystyrene or polyurethane foam with the interior surfaces coated with polytetrafluoroethylene or an epoxy resin coating to provide a generally heat-resistant self-cleaning and scale-resistant vaporization chamber. This chamber 21 is generally circular with a conical bottom wall having an opening 22 communicating with the lower portion 20 of the shell 19. This lower opening 22 of the chamber 21 permits the flow of fluid from the upper larger water storage chamber 24 surrounding the cylindrical vaporization chamber 21 into the chamber 21 via a one-way check valve 25 positioned in a support ring or flange 23 surrounding the chamber 21. The water enters the reservoir 24 through a suitable supply line 26 leading from a larger reservoir or from a main water supply line into the upper reservoir through a float-controlled or pressure-controlled valve 27. The valve 27 maintains a constant water level within the reservoir 24. Water from the reservoir 24 flows through the valve 25 and into the lower reservoir or portion 20 of the shell 19 and then into the vaporization chamber 21 where it is heated by suitable heating means such as a pair of circular conductive plates or electrodes 29 and 30 which are concentrically positioned within the vaporization chamber 21 and which are connected by suitable conductors 31 and 32 to a control box 34. The circular electrodes 29 and 30 protect the vaporizer against overheating in the event that some malady may occur in the supply of water to the reservoir and vaporization chamber. Yet the position of the electrodes permits the use of substantially all of the water in the reservoir before the supply of water is exhausted. Alternatively polytetrafluoroethylene coated immersion heaters equipped with thermostats may be used to bring the water in the vaporization chamber 21 to a boil.

In the upper portion of the vaporization chamber 21 are a series of openings 36 which permit gases to enter the vaporization chamber at the top thereof. The upper end of the vaporization chamber 21 communicates with the inlet side of the fan 17 such that the fan serves to draw gases through the openings 36 and to draw the vapor rising from the liquid in the vaporization chamber 21 directly into the fan 17 to be mixed with the gases and forced upward into the plenum 15.

The air and/or therapeutic gas to be mixed with the steam is introduced into the upper portion of the reservoir 24 through the cover 37 of the reservoir. A fluid supply line 39 is connected to the cover 37. This fluid is drawn by the suction of the inlet side of the fan 17 through the supply line 39. The gas that will enter the vaporizer-humidifier may be either ambient room air or it may be special therapeutic gas, for example, oxygen. It may be a combination of the ambient air and the oxygen. A valve 40 has one inlet permitting the ambient air to enter the valve and is provided with a fitting to which may be connected, through a suitable constant pressure regulator valve 41, a tank of oxygen 42. The valve 40 has a volume control which regulates the percentage of the gas which is mixed with the air and the amount of either which will be introduced to the humidifier. A specific embodiment of this valve may be the valve illustrated in copending application Ser. No. 25,986, filed Apr. 6, 1970 now U.S. Pat. No. 3,633,602. The fluid drawn into the vaporizer-humidifier 16 may be preheated by a heater 44 positioned within the conduit 39 between the valve 40 and the inlet to the reservoir to control the humidity of the gas entering the incubator. The temperature of the gas is set to a predetermined temperature by a regulator 45, such as rheostat, connected to the heater for controlling the amount of heat added to fluid before it enters the humidifier. As the temperature of the fluid entering the reservoir is increased the percentage of relative humidity in the gas finally directed into the incubator will be lowered while maintaining the same at a constant temperature.

The control unit 34 is responsive to a thermistor 47 positioned in the plenum 15 above the discharge side of the fan 17. The thermistor 47 will sense the change in temperature of the warmed moist gas entering the base 12. This thermistor 47 will thus provide means to signal the control unit 34 to electronically regulate the power supplied to the vaporizer heating means 29 and 30, to afford an effective control on the amount of steam vapor generated from the vaporization chamber 21 which is mixed with the air by the fan. A regulator 48 is provided to adjust the temperature to be maintained by the control unit 34 for the gases entering the incubator.

The vaporizer-humidifier 16 is capable of providing a supercooled steam or a supersaturated atmosphere at any given temperature below 100.degree.C and one atmosphere pressure. The physical characteristics of steam or pure H.sub.2 O gas under one atmosphere are well known and tabulated in handbooks of physical chemistry. The characteristics of steam are tabulated down to 100.degree.C or the boiling point of H.sub.2 O. There have been none established below 100.degree.C and one atmosphere because it has been unknown to exist below this temperature except up to 100 percent saturation at any given temperature.

This apparatus draws the stem or gaseous H.sub.2 O vapor off the boiling water at 100.degree.C and immediately and thoroughly mixes it with ambient air or other preferred gases, i.e., O.sub.2. This is done so rapidly that the steam has no time to condense to liquid H.sub.2 O nor does the H.sub.2 O have a particle to condense around. This mixture of supercooled steam or supersaturated air is immediately discharged from the apparatus.

With a highly efficient apparatus a negligable amount of steam will be able to condense to H.sub.2 O liquid and release its heat of condensation (540 Cal/gm H.sub.2 O). Calculations of "relative humidity" will thus deal with only the specific heat of gaseous H.sub.2 O (0.482 Cal/gm H.sub.2 O) and the specific heat of air (0.243 Cal/gm H.sub.2 O). This permits the cooling of steam with relatively small quantities of air or other gases to a safe temperature or one which will not cause damaging burns to live tissue. In brief, this vaporizer has taken the burn out of steam and made it safe as a source of humidity for medical applications. There may be many other applications other than in medicine for such a vaporizer but only those in medicine will be mentioned here. There is not known an apparatus in the prior art which provides humidity in excess of 100 percent relative humidity at a given temperature at one atmosphere. The closest apparatus is a nebulizer but they merely suspend fine water particles in the atmosphere by ultrasonic sound waves or by atomization ("cold" humidifier). These particles of liquid H.sub.2 O may carry dangerous organisms, allergens or mineral dust and therefore pose many medical hazards not taken lightly in recent studies. Supercooled steam contains no dangerous organisms, allergens or mineral dust. It does still retain its heat of vaporization which is released slowly as condensation occurs and does not pose a burn hazard, thus immediate and obvious medical applications are with inhalation therapy and humidification of medicinal gases (i.e., O.sub.2) for inhalation purposes. The present invention combines the above applications and, in addition, utilizes the inherent heat of condensation to very efficiently and exactingly heat an infant warmer-incubator.

The computations hereunder lend support to the statement that the present invention does actually produce superaturated atmosphere or supercooled steam at one atmosphere and at temperatures below 100.degree.C, although to date no prior apparatus has been available and no physical properties are available in handbooks of physics and chemistry relating thereto. These properties shall undoubtedly be proven out and made available in the near future.

The following sample computations are based on a machine where there is no condensation and show the relative humidity of the mixture at various temperatures and volumns of air required to cool the steam to a given temperature, with the air originally at 72.degree.F (22.22.degree.C) 30 percent relative humidity and at one atmosphere.

1. (Mw)(Cps)(.DELTA.t) = Cal. given up in cooling 1 molar volume of steam from 100.degree.C.

2. (ma)(Cpa)(.DELTA.t) = Cal. taken up by 1 molar volume of air in heating to desired temperature.

3. Calories given by steam/Calories taken up by air = moles of air at given temperature required to cool 1 mole of steam. ##SPC1##

5. [Answer from (3) above + 1 mole steam] [grams H.sub.2 O/mole gas at 100 percent R.H. and 100.degree.C] = grams of H.sub.2 O capacity of gas at 100 percent R.H. for number of volumes of air and steam.

6. (grams H.sub.2 O/mole) + (grams H.sub.2 O/mole of air at 72.degree.F and 30 percent R.H.)[moles of air from (3)] = grams of H.sub.2 O actually present in mixture.

7. Grams of H.sub.2 O in mixture .times. 100/Grams of H.sub.2 O in air at 100 percent R.H. = percent R.H. of mixture.

wherein:

Mw is - molecular weight of H.sub.2 O,

Ma is - molecular weight of air,

Cps is - specific heat of steam,

Cpa is - specific heat of air,

.DELTA.t is - change in temperature in degrees centigrade,

Cal. is - calories, and

R.h. is - relative humidity, however, by definition relative humidity does not exceed 100 percent.

Computations for Relative Humidity of Gas Discharged From Vaporizer-Humidifier:

I. At 99.6.degree.F or 37.56.degree.C.

1 (18.0) (0.482) (62.445.degree.c) = 541.773 cal.

2 (29.0) (0.243) (15.333.degree.C) = 108.054 Cal.

3 541.773 Cal. from steam/108.054 Cal. to air = 5.014 molar volume of air at 72.degree.F required to cool 1 molar volume steam from 100.degree.C to 37.555.degree.C.

4 (24.2) (5.014) 30.7 = 3.952 volumes of air to cool 1 volume steam from 100.degree.C to 37.555.degree.C.

5 (6.014) (1.1517) = grams H.sub.2 O (6.926) capacity with R.H. 100 percent for 6.014 molar volume of mixed steam and air.

6 18 + (0.143)(5.014) = 18.717 gram H.sub.2 O actually present in the mixture.

7 18.717 gram H.sub.2 O .times. 100/6.926 gram H.sub.2 O capacity = 270.243 percent R.H.

II. At 85.degree.F or 29.degree.C.

1 (18)(0.482)(71.degree.c) = 616.0 cal. from steam.

2 (29)(0.213)(7.degree.C) = 49 Cal. required by air.

3 616.3/49 = 12.6 molar volume air to 1 molar volume steam.

4 (24.2)(12.6)/30.7 = 10.8 volume air to 1 volume steam.

5 (13.6)(0.7 gram H.sub.2 O) = 9.5 grams H.sub.2 O capacity at 29.degree.C and 100 percent R.H.

6 18 + (12.6)(0.143) = 19.8 grams H.sub.2 O actually present.

7 19.8/9.5 = 208 percent R.H.

III. At 80.degree.F or 26.66.degree.C.

1 (18.0)(0.482)(73.333.degree.c) = 636.237 cal. (steam).

2 (29.0)(0.243)(4.444.degree.C) = 31.320 Cal. received by air.

3 (6.36.237) Cal. (steam)/(31.32) Cal. (air) = 20.314 molar volume air to cool 1 molar volume steam to 80.degree.F.

4 (24.2)(20.314)/30.7 = 16.007 volume air to cool 1 volume steam to 80.degree.F.

5 (21.314)(0.6186) = 13.185 gram H.sub.2 O capacity in mixture at 100percent R.H. at 80.degree.F.

6 18 + (0.143)(20.314) = 20.905 gram H.sub.2 O vapor actually present in mixture

7 20.905 gram H.sub.2 O .times. 100 percent/13.185 gram H.sub.2 O = 158.551 percent R.H.

The plenum 15 as best illustrated in FIGS. 1 and 5 is connected generally centrally of the base 12. The gases entering the base under the pressure of the fan 17 tend to be dispersed by a baffle 49 and by a pan 50 which is slidable from one end into the base and supported by a suitable guide and support means on the bottom wall 51 of the base 12 such as the spacers or legs 52. The pan 50 serves to collect any fluids excreted by the infant or otherwise dispelled into the incubator during the nursing care or surgical treatment of the infant. The pan 50 or its supports may also serve to support an X-ray cassette to permit X-rays to be taken without removing the infant from the incubator.

Side walls 55 and 56, as illustrated, are formed with longitudinally extending rails or guides 57 which form guide means for receiving the hood 14 and a frame 60 having a large central opening over which is positioned a porous nonabsorbent material 61 which will form the hammock-type bed for the infant. Alternatively, the walls 55 and 56 could be thicker. An example of a suitable material from which to form this bed may be loosely woven fibers of polypropylene forming a continuous porous water repellent, non-absorbent fabric. This bed frame 60 may thus be made to be disposable as a diaper during the time an infant is confined to the incubator and may be furnished in sterilized form for replacement.

The end wall 53 is formed as a hinged panel connected to the bottom wall 51. This panel or end wall 53 permits ready access to the pan 50 allowing insertion and removal and insertion of the X-ray film cassette as discussed above.

The guides 57 in the side walls have a shouldered area or are set below the upper edge of the walls to form a ledge to receive a generally rectangular hood 14 having an open bottom to mate with the open upper side of the base and an open top. The hood 14 comprises an open rectangular frame and four converging walls to form a smaller open top for the hood 14. The frame is formed by a four narrow strips to form a plate 66 having a large central opening. Around the outer periphery of the plate 66 are hinges 68 connecting four transparent trapezoidal panels 70, 71, 72 and 73 forming the walls which are normally disposed in a converging relation from the base 12. The upper free edges of the panels define an upper aperture 74 slightly smaller than the dimensions of the hammock. The plate 66 is formed with a rib 75 which depends therefrom and which fits inside the end walls 53 and 54 and the side walls 55 and 56 of the base. The rib 75 and the plate 66 permit the frame 60 for the hammock to be easily inserted into the incubator by lowering one wall 72 or 73. The converging panels 70, 71, 72 and 73 serve to apply back pressure to the gases within the incubator, thus restricting air from entering the incubator through the aperture 74, resulting thereby in generally unidirectional (upward) flow of the warm, humidified, oxygen-abundant gases in the incubator. This aperture 74 also permits easy access to the infant on the frame 60. The panels may be moved individually to a position near the walls 53-56 as illustratd in FIG. 5 to permit nursing care or surgical treatment (i.e., endotracheal intubation) on the child. The panels could all be lowered and a drape placed over the base 12 if necessary and the child would be maintained in a warm humid environment.

In operation the desired environment is determined. If it is desired that there be a large amount of vapor in the environmental gas, at normal body temperature with an abundance of oxygen, the valves 41 and 40 are adjusted for regulation of the amount and mixture of gases. The control 34 will be set for the proper temperature which will be maintained by the thermistor 47. The vaporization chamber is heated to deliver the steam and the fan 17 will direct the gases into the plenum 15 to be distributed through the incubator and later exhausted through the aperture 74.

The control of the heat to the vaporizer allows a constant temperature condition to be maintained. The amount of fluid to be mixed with the steam is preset and the temperature thereof is seto provide a control for the humidity of the fluid delivered through the plenum into the incubator. The baby may remain unclothed in the incubator of this invention and will be easily observed by the nurses such that they can grade the progress and condition of the child.

All materials of which the incubator is formed may be radiolucent materials so as not to interfere with X-ray or fluoroscopy studies.

While this invention is directed to and describes a single modification of the present invention, it will be understood that certain changes may be made therein without departing from the spirit or scope of the invention as defined in the appended claims. One modification may be to provide the opening for the ingress of the warm humidified gases at an end of the incubator rather than in the bottom wall. While the air flow pattern may be more difficult to regulate the bottom of the incubator may be more exposed for purposes of fluoroscopy studies.

Claims

What is claimed is:

1. An incubator for providing a controlled environment of a predetermined temperature and humidity to an infant while permitting ready access to the infant for routine nursing care and technical procedures without removing the infant or working through portholes, said incubator comprising:

a generally rectangular base having a bottom wall,

side and end walls with an open upper side,

a generally rectangular hood having an open end positioned over said open upper side of said base and comprising four walls which are hinged along their lower edges and, in their normal position, are inclined to converge upwardly from said base, said four walls have an extent less than required to meet along their upper edges to define an aperture above said base smaller than said open upper side of said base but large enough to permit some nursing care to be carried out therethrough,

bed means forming a porous nonabsorbent support for an infant,

means for supporting said bed means and said hood to dispose said bed means and the lower edges of said four walls substantially in a common plane,

plenum means communicating with said base for directing warm, humidified fluid into the incubator below said bed means, and

environmental control means for introducing warm, humidified gases into said plenum means at a pressure above atmospheric pressure sufficient to maintain flow of fluid upward through the incubator and out said aperture, said environmental control means comprising,

vaporizer means including a water vaporization chamber and heating means disposed in said chamber for producing a supply of steam,

valve means for admitting fluid into said vaporizer means, and

blower means for mixing said fluid and said steam and directing said mixture into said plenum means and said base at said pressure above atmospheric pressure whereby said mixture passes through said bed means and said inclined walls of said hood serve to maintain said mixture about a said infant on said bed means.

2. The incubator according to claim 1 wherein said four walls are transparent trapezoidal panels and said hood comprises:

a rectangular frame supported on the upper edge of said walls forming said base, and

hinge means on said frame for mounting said four walls to the periphery of said frame to be individually lowered along said walls of said base.

3. The incubator according to claim 1 wherein at least one end wall of said base is hinged to permit access below said bed means, and wherein a removable tray is supported in said base below said bed means, said tray being formed and disposed to distribute fluid entering said base through said plenum means.

4. The incubator according to claim 1 wherein said vaporizer means comprises a cylindrical vaporization chamber, means for maintaining a supply of water in said vaporization chamber, said heating means being disposed in said vaporization chamber to heat the water to boiling temperature to produce said supply of steam, said vaporization chamber having an open bottom through which purged minerals may fall and having openings about its upper edge to permit fluid to enter the vaporization chamber, and wherein said blower means is disposed with its inlet opening directly above and over the upper end of said vaporization chamber.

5. The incubator according to claim 4 wherein a thermistor is positioned in said plenum and control means are provided for adjusting said heating means.

6. The incubator according to claim 4 wherein gas mixing valve means is connected to communicate through said openings with said chamber for mixing ambient air and at least one therapeutic gas in predetermined proportions and controlling the flow of said mixture of fluid into said chamber.

7. The incubator according to claim 6 wherein a second heating means is positioned between said mixing valve means and said chamber for heating said fluid flowing into said chamber.

8. The incubator according to claim 4 wherein said heating means comprises a pair of concentrically positioned conductive cylindrical rings each connected to a conductor.

9. The incubator according to claim 1 wherein said bed means comprises a rectangular frame upon which is mounted a nonabsorbent fabric, and said incubator comprises support means for supporting said bed means at said open upper side of said base.

10. The incubator according to claim 3 wherein said plenum means is positioned to communicate with the central portion of the bottom wall of said base, whereby said fluid and steam will be directed around said tray and upward through said bed means.

11. The incubator according to claim 10 wherein said hood comprises,

a rectangular frame supported on the upper edge of said walls forming said base, and

four transparent trapezoidal panels hinged to the periphery of said frame to be individually lowered along said walls of said base, and

wherein guide means support said bed means at said open upper side.