A patient warming system comprising an inflatable thermal blanket

Abstract

Invention relates to a patient warming system comprising an inflatable thermal blanket (1) having an inlet port (14) and an outlet port (15). The system comprises a heated air supply unit (2) that prepares and supplys a heated air flow (F) to the inflatable thermal blanket (1) via an inlet hose (3). The system characterized in that it comprises a recirculation hose (4) which from one of its ends is fluidly connected to the outlet port (15) of the inflatable thermal blanket (1) and from an opposite end is fluidly connected to the air flow inlet (28) of the heated air supply unit (2) providing the heated air flow (F) from the inflatable thermal blanket (1) back to the heated air supply unit (2). The invention also includes a method to control a supply of the heated air flow (F) to the inflatable thermal blanket (1) of the system.

Description

A PATIENT WARMING SYSTEM COMPRISING AN INFLATABLE THERMAL BLANKETDESCRIPTIONField of the invention

[0001] Invention relates to a patient warming system and control of the system for providing a safe operation thereof.Background of the invention

[0002] In patient warming systems, an inflatable thermal blanket is used to deliver a heated, thermally-regulated air to a patient, which is human or animal. The device is inflated with the pressurized, heated, thermally-regulated air and has one or more surfaces adapted for expelling the air onto a patient. Such devices are positioned on a patient. The U.S. patent application publications Nos. 5,324,320 and 5,405,371, for example, describe patient warming systems comprising inflatable thermal blankets that lie on a patient, expelling pressurized, heated or warmed air through multiple holes in lower surface that faces the patient.

[0003] The US patent application publication No. US2023 / 190516 discloses a thermal device comprising an inflatable blanket configured to transport warm air internally. The conduit structure is configured to provide conduit to transport the warm air externally to the inflatable blanket. The recirculating assembly is configured to inflate the inflatable blanket with the warm air and to cause the warm air to flow from the first port to the second port in a first direction, and to recirculate the warm air through the conduit structure to flow from the second port to the first port in the first direction. The upper wall faces ambient air and has a first thermal conductivity. The lower wall faces the subject body and has a second thermal conductivity higher than the first thermal conductivity.

[0004] Even though the prior art patient warming systems utilizes various materials for maintaining the warmth within the thermal blankets, it does not solve the problem of uneven distribution of warmth within the thermal blanket. Use of various materials cannot solve it and different approaches should be investigated. Hence, the aim of the invention is to search for solution, how to provide even distribution of warmth within the thermal blanket.

[0005] International patent application publication No. W02005007054A1 discloses a system for controlling pressure and temperature in a cushion intended for a patient. The system comprises a blanket made by a flexible material that is tight or is provided with a tight layer, wherein the blanket of the flexible material encloses at least one volume and is comprising at least a first connection portion and a second connection portion, which connection portions are arranged to function as inlets and / or outlets. The system also comprises a control unit that is arranged to transfer one or more pressurised, tempered mediums to the blanket alternately via the first connection portion and the second connection portion.

[0006] The prior art also includes a Bair Hugger™ system owned by 3M™ or Arizant Healthcare™ Inc., a 3M™ company. The system is covered by multiple patent publications Nos. EP1139827B1, EP1937196B1, EP2189137B1, EP3236893B1, US2019336328A1, US2023096465A1, WO2014189747A1 and WO2018075579A1. For example, the US patent application No. US11234860B2 discloses a warming blanket for patient warming having a structure comprising a first layer of material forming a bottom layer with openings to allow a profusion of air through the bottom layer, a second layer of material forming an upper layer wherein the upper layer is coupled to the bottom layer via a plurality of seals to form a plurality of interconnected air passageways, and an inlet located on the upper or bottom layers.Summary of the invention

[0007] The aim is reached by a design of a patient warming system comprising an inflatable thermal blanket, a heated air supply unit, an inlet hose fluidly interconnected between the inflatable thermal blanket and the heated air supply unit for providing a heated or warmed air flow from the heated air supply unit to an into the inflatable thermal blanket. The inflatable thermal blanket in this invention is intended to be any inflatable thermal device such as pads, mattresses, covers and equivalent structures.

[0008] The present invention is characterized in that the inflatable thermal blanket having an upper wall or sheet, a lower wall or sheet and a side wall interconnecting said upper and lower walls forming an inner environment that is sealed from an outer environment. The inflatable thermal blanket comprises an inlet port and an outlet port. The inflatable thermal blanket further comprises an intermediate wall arranged between the upper wall and the lower wall dividing and separating the inner volume of the inflatable thermal blanket so that an upper volume is formed between the upper wall and the intermediate wall and so that a lower volume is formed between the intermediate wall and the lower wall. In addition, an intermediateopening is formed in the intermediate wall fluidly connecting the lower volume to the upper volume so that the heated air can flow from the lower volume into the upper volume. The intermediate opening is arranged in a middle of a distance that is travelled by the incoming heated airflow from the inlet port to the outlet port of the inflatable thermal blanket.

[0009] In case of the inflatable thermal blanket with the intermediate wall, the inlet port of the inflatable thermal blanket is arranged at the lower volume of the inflatable thermal blanket so that the incoming heated airflow first enters the lower volume. The outlet port of the inflatable thermal blanket is arranged at the upper volume of the inflatable thermal blanket so that the heated airflow within the upper volume exits the inflatable thermal blanket. Such arrangement of the intermediate opening, the outlet port and the inlet port provides thermal equilibrium.

[0010] The heated air supply unit comprises an air blower, a heater, an outlet temperature sensor, a flow sensor and a pressure sensor. The heated air supply unit comprises an air flow outlet and an air flow inlet, where the heated air supply unit by means of the air blower takes an air from the air flow inlet, heats up the air by means of the heater and releases the heated air flow from the heated air supply unit through the air flow outlet. The inlet hose from one of its ends is fluidly connected to the air flow outlet of the heated air supply unit and from an opposite end is fluidly connected to the inlet port of the inflatable thermal blanket providing the heated air flow from the heated air supply unit and into the inflatable thermal blanket.[Oi l] The patient warming system further comprises a recirculation hose, which from one of its ends is fluidly connected to the outlet port of the inflatable thermal blanket and from an opposite end is fluidly connected to the air flow inlet of the heated air supply unit providing the heated air flow from the inflatable thermal blanket back to the heated air supply unit. Hence, completely closed and recirculated air flow is provided without forced air exit as it is with the prior art systems. One from many benefits of such recirculating systems is such that the air exiting from inflatable thermal blanket is not expelled into environment which can be a surgery room. Hence, there is no unnecessary air flow withing the operation room that would disturb climate-control of the operation room as well as no forced flow that could bring any unwanted dirt from the floor and into operation area. Moreover, such recirculating system allows to provide more efficient energy conversion as the heated air is not expelled from the system but is used repeatedly multiple times.

[0012] The patient warming system further comprises a flow control valve installed at the outlet port or in the recirculation hose. The control valve through the control unit of the system is configured to control the flow of air.

[0013] The patient warming system further comprises an auxiliary pump which is in fluid connection with the heated air supply unit and configured to maintain a pre-set pressure within the inflatable thermal blanket.

[0014] Moreover, the heated air supply unit comprises a recirculated air flow temperature sensor configured to measure a temperature of the heated air flow that enters the heated air supply unit from the inflatable thermal blanket. The heated air supply unit further comprises a pressure limiting valve configured to release an air within the system if the air pressure within the system exceeds a pre-set threshold value.

[0015] Implementation of the recirculated air flow system with the inflatable thermal blanket consisting of three layers of air non-permeable material forming two volumes. The lower volume facing the patent and the upper volume facing the outer environment provide multiple technical advantages. First, in contrast to the prior art, implementation of the recirculated air flow provides closed air flow cycle, in result of which an air circulation in the outer environment is not disturbed. It also uses forced air circulation in such a way that in contrast to the prior art, in the design of which every time the system heats air into inflatable thermal blanket from room temperature to the required temperature, and the warm air then exits into the outer environment, therefore the invention has less influence on the outer environment temperature as it uses recirculation, that is, it heats the already warm air from the mattress. Also, the system uses less energy as it warms the air that exits from the inflatable thermal blanket and its temperature is higher than the temperature of the outer environment. This is crucial for medical operation halls, where any disturbance of the outer environment can have negative consequences, for example, raising or circulating the particles in the air into the operation field. Secondly, notwithstanding that the primary function of the inflatable thermal blanket is to warm the patient, in solutions of the prior art the surface of the blanket facing the patient and the surface of the blanket facing the environment, are heated nearly identically, thus the irradiated energy from the patient’s side and the outer environment’s side is the same, which also reduces the energy efficiency of the inflatable thermal blanket and is warming up the outer environment which it is not designed for. The present invention is superior in comparison to the prior art in the design aspects that provide a closed-cycle system therefore it is energy efficient and does not emit unwanted hot air volume into the outer environment.

[0016] Solutions described in the prior art, in regards to warming a patient, comprise asymmetric solution, that is they are designed so that in the prior art the warm air comes in from the bottom part and exits at the upper part, therefore it is warmer at the bottom and cools down until it reaches the upper part; also in the prior art the heating surface is divided into twoparts - left and right. The air first heats the one side of the patient’s body where the flow comes from the left side of the patient from the side of the legs towards the head zone, then turns from left to right, forming U shaped flow from left side to the right side and as it gives away the energy for heating the patient’s left side, thus the temperature of the air circulating in the mattress’s left side is higher than the temperature of the air circulating in the mattress’s right side. Thus, the left and the right side of the body are not heated uniformly, especially in the area of the patient’s legs. In the present invention the surface facing the patient warms up first, after that the air flow turns, and warms up the surface facing the outer environment, thus the thermal energy primarily is used for warming the patient as the side of the mattress facing the patient, is warmed up first. Also, due to the design, the layer of the mattress facing the outer environment performs insulation function for the flow facing the patient, thus stabilizing the temperature along all the parts of the mattress facing the patient. Thus, a larger portion of the energy is directed to the patient than to the mattress which results in double benefit, and the amount of the energy, which is emitted from the layer facing the patent, is higher than the energy emitted from the layer facing the outer environment. Thirdly, the flow is provided from the entire width of the mattress, due to which the supplied warm air is distributed evenly along both the left and the right side, in contrast to the prior art, left and right side are heated uniformly. At the same time, in the present invention, the lower volume of the thermal blanket functions as a heating means and the upper volume of the thermal blanket functions as an insulation means. Due to fact that the volume facing the patient is additionally insulated from outer environment by the second volume facing the outer environment, the lower and upper parts of the body are heated much more uniformly. Moreover, such arrangement with minimal or no temperature drops within the thermal blanket provides more effective thermal management, which is superior in comparison to solutions of the prior art, which do not comprise an insulation layer between the patient heating layer and the outer environment.

[0017] The present invention is also a method for controlling a pre-set supply of a heated air flow to the inflatable thermal blanket of the patient warming system. The method comprises a step, where the supply of the heated air flow to the inflatable thermal blanket is stopped if the pressure sensor through its control unit detects a drop of pressure below a pre-set threshold pressure value and that dropped pressure is maintained for a pre-set period of time. The pre-set threshold pressure value and the pre-set period of time is set through the control of the system by a user of the system.

[0018] Additionally, the supply of the heated air flow to the inflatable thermal blanket is stopped if a temperature difference between the outlet temperature sensor and the recirculatedair flow temperature sensor increases above a pre-set threshold temperature difference value. The pre-set threshold temperature difference value is set through the control of the system by a user of the system.

[0019] Aforementioned method steps make system safer. In case of blanket or hose puncture, or any malfunction of the heated air supply unit, the system will stop avoiding patient injury.Brief description of the drawings

[0020] The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments of the invention.

[0021] Fig. l is a block diagram showing the elements of the patient warming system and their relationships to each other. The thermal blanket is in one volume configuration.

[0022] Fig. 2 is a cross-section view (A-A) of the inflatable thermal blanket (1) as seen in Fig. 1 in its transversal direction.

[0023] Fig. 3 is a cross-section view (A-A) of the inflatable thermal blanket (1) as seen in Fig. 1 in its longitudinal direction.

[0024] Fig. 4 is a block diagram showing the elements of the patient warming system and their relationships to each other. The thermal blanket is in double volume configuration having an upper volume (92) and a lower volume (91) divided by an intermediate wall (17)

[0025] Fig. 5 is a block diagram of the inflatable thermal blanket (1) comprising the intermediate wall (17) that divided the thermal blanket in the upper volume (92) and the lower volume (91) as seen in Fig. 4.

[0026] Fig. 6 is a cross-section view (A-A) of the inflatable thermal blanket (1) as seen in Fig. 5 in its transversal direction.

[0027] Fig. 7 is a cross-section view (B-B) of an inlet port (14) and an outlet port (15) of the inflatable thermal blanket (1) as seen in Fig. 5.

[0028] Fig. 8 is a cross-section view (C-C) of the inflatable thermal blanket (1) as seen in Fig. 5 in its longitudinal direction.Detailed description of the embodiments

[0029] The preferred embodiments of the invention are now described with reference to the figures to illustrate objectives, advantages, and efficiency of the present invention.

[0030] Fig. l is a block diagram showing the elements of the patient warming system and their relationships to each other. A patient warming system comprises an inflatable thermal blanket (1) that has an inlet port (14) and an outlet port (15). The system comprises a heated air supply unit (2) that prepares and supply a heated or thermally regulated airflow (F) to the inflatable thermal blanket (1). This connection between the heated air supply unit (2) and the inflatable thermal blanket (1) is provided by an inlet hose (3). The inlet hose (3) from one of its ends is fluidly connected to the air flow outlet (27) of the heated air supply unit (2) and from an opposite end is fluidly connected to the inlet port (14) of the inflatable thermal blanket (1) providing the heated air flow (F) from the heated air supply unit (2) and into the inflatable thermal blanket (1).

[0031] As seen in Figs. 1 and 4, the heated air supply unit (2) comprises an air blower (21), a heater (22), an outlet temperature sensor (23), a flow sensor (24), and a pressure sensor (25). The heated air supply unit (2) also comprises an air flow outlet (27) and an air flow inlet (28), where the heated air supply unit (2) by means of the air blower (21) takes an air from the air flow inlet (28), heats up the air by means of the heater (22) and releases the heated air flow (F) from the heated air supply unit (2) through the air flow outlet (27). The heated air supply unit (2) is controlled by means of a control (8) and a display (9) attached thereto.

[0032] The patient warming system characterized in that it comprises a recirculation hose (4) which from one of its ends is fluidly connected to the outlet port (15) of the inflatable thermal blanket (1) and from an opposite end is fluidly connected to the air flow inlet (28) of the heated air supply unit (2) providing the heated air flow (F) from the inflatable thermal blanket (1) back to the heated air supply unit (2). The system further comprises a flow control valve (5) installed at the outlet port (15) or in the recirculation hose (4) (see Figs. 1 and 4).

[0033] The patient warming system is also characterized in that the heated air supply unit (2) comprises a recirculated air flow temperature sensor (7) configured to measure a temperature of the heated air flow (F) that enters the heated air supply unit (2) from the inflatable thermal blanket (1) and a pressure limiting valve (26) configured to release an air within the system if the ir pressure within the system exceed a pre-set threshold value. The system also comprises an auxiliary pump (6) which is in fluid connection with the heated air supply unit (2) and configured to maintain a pre-set pressure within the inflatable thermal blanket (1), The auxiliary pump (6) comprises an environment air inlet (61) for taking an air from outer environment and supplying it to the heated air supply unit (2) (see Fig. 1 and 4).

[0034] As seen in Figs. 1 to 3, the inflatable thermal blanket (1) has an upper wall (11), a lower wall (12) and a side wall (13) interconnecting said upper and lower walls (11; 12) forming an inner environment (IN) that is sealed from an outer environment (OUT).

[0035] The inflatable thermal blanket (1) further comprises intermediate side walls (16) (see Fig. 1, 2, 5 and 6) increasing overall integrity of the inflatable thermal blanket (1).

[0036] Figs. 4 to 8 disclose the invention having the inflatable thermal blanket (1) that comprises an intermediate wall (17) arranged between the upper wall (11) and the lower wall (12) dividing and separating the inner volume of the inflatable thermal blanket (1) into an upper volume (92) and a lower volume (91). The intermediate wall (17) comprises four intermediate openings (18) fluidly connecting the upper volume (19) to the lower volume (91). The intermediate openings (18) are arranged in a middle of a distance that is travelled by the incoming heated airflow (F) from the inlet port (14) to the outlet port (15) of the inflatable thermal blanket (1). The intermediate wall (17) itself is arranged parallel to the upper wall (11) and the lower wall (12) so that the intermediate wall (17) forms intermediate separating layer. The inlet port (14) of the inflatable thermal blanket (1) is arranged at the lower volume (91) of the inflatable thermal blanket (1) so that the heated airflow (F) incoming from the heated air supply unit (2) first enters the lower volume (91) of inflatable thermal blanket (1). However, the outlet port (15) of the inflatable thermal blanket (1) is arranged at the upper volume (19) of the inflatable thermal blanket (1) so that the heated airflow (F) within the upper volume (19) exits the inflatable thermal blanket (1) and goes into the recirculation hose (4), and back to the heated air supply unit (2). Aforementioned arrangement of the inlet port (14), the intermediate openings (18) and the outlet port (15) provides even distribution of warmth within the thermal blanket.

[0037] While the invention may be susceptible to various modifications and alternative forms, specific embodiments of which have been shown by way of example in the figures and have been described in detail herein, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention includes all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the following claims.

Claims

CLAIMS1. A patient warming system comprising: an inflatable thermal blanket (1) having an upper wall (11), a lower wall (12) adapted to be faced against a patient (P) and a side wall (13) interconnecting said upper and lower walls (11; 12) forming an inner environment (IN) that is sealed from an outer environment (OUT), wherein the inflatable thermal blanket (1) comprises an inlet port (14) and an outlet port (15); a heated air supply unit (2) comprising: an air blower (21); a heater (22); an outlet temperature sensor (23); a flow sensor (24); a pressure sensor (25); a recirculated air flow temperature sensor (7), a control (8) and a display (9) attached thereto, wherein the heated air supply unit (2) comprises an air flow outlet (27) and an air flow inlet (28), where the heated air supply unit (2) by means of the air blower (21) takes an air from the air flow inlet (28), heats up the air by means of the heater (22) and releases the heated air flow (F) from the heated air supply unit (2) through the air flow outlet (27), and wherein the recirculated air flow temperature sensor (7) is configured to measure a temperature of the heated air flow (F) that enters the heated air supply unit (2) from the inflatable thermal blanket (1) and a pressure limiting valve (26) configured to release an air within the system if the ir pressure within the system exceed a pre-set threshold value; an inlet hose (3), which from one of its ends is fluidly connected to the air flow outlet (27) of the heated air supply unit (2) and from an opposite end is fluidly connected to the inlet port (14) of the inflatable thermal blanket (1) providing the heated air flow (F) from the heated air supply unit (2) and into the inflatable thermal blanket (1); a recirculation hose (4) which from one of its ends is fluidly connected to the outlet port (15) of the inflatable thermal blanket (1) and from an opposite end is fluidly connected to the air flow inlet (28) of the heated air supply unit (2) providing the heated air flow (F) from the inflatable thermal blanket (1) back to the heated air supply unit (2); an auxiliary pump (6) which is in fluid connection with the heated air supply unit (2) and configured to maintain a pre-set pressure within the inflatable thermal blanket (1), wherein the auxiliary pump (6) comprises an environment air inlet (61);characterized in that the inflatable thermal blanket (1) comprises an intermediate wall (17) arranged between the upper wall (11) and the lower wall (12) dividing and separating the inner volume of the inflatable thermal blanket (1) so that an upper volume (19) is formed between the upper wall (11) and the intermediate wall (17) and so that a lower volume (91) is formed between the intermediate wall (17) and the lower wall (12), and in that an intermediate opening (18) is formed in the intermediate wall (17) fluidly connecting the lower volume (91) to the upper volume (19) so that the heated air can flow from the lower volume (91) into the upper volume (92).

2. The patient warming system according to claim 1 , characterized in that the intermediate wall (17) is arranged parallel to the upper wall (11) and the lower wall (12) of the inflatable thermal blanket (1).

3. The patient warming system according to claim 1 or 2, characterized in that the inlet port (14) of the inflatable thermal blanket (1) is arranged at the lower volume (91) of the inflatable thermal blanket (1) so that the incoming heated airflow (F) first enters the lower volume (91).

4. The patient warming system according to any of claim 1 to 3, characterized in that the outlet port (15) of the inflatable thermal blanket (1) is arranged at the upper volume (19) of the inflatable thermal blanket (1) so that the heated airflow (F) within the upper volume (19) exits the inflatable thermal blanket (1).

5. The patient warming system according to any of claim 1 to 4, characterized in that the intermediate opening (18) is arranged in a middle of a distance that is travelled by the incoming heated airflow (F) from the inlet port (14) to the outlet port (15) of the inflatable thermal blanket (1).

6. The patient warming system according to any of claim 1 to 5, characterized in that the system further comprises a flow control valve (5) installed at the outlet port (15) or in the recirculation hose (4) and through the control unit (8) of the system is configured to control the flow of air.

7. A method for controlling a pre-set supply of a heated air flow (F) to a inflatable thermal blanket (1) of the patient warming system according to any of claim 1 to 6, wherein the supply of the heated air flow (F) to the inflatable thermal blanket (1) is stopped if the control (8) of the system by means of the pressure sensor (25) detects a drop of pressure below a pre-set threshold pressure value and that dropped pressure is maintained for a pre-set period of time, wherein the pre-set threshold pressure value and the pre-set period of time is set through the control (8) of the system by a user of the system.

8. The method according to Claim 7, wherein the supply of the heated air flow (F) to the inflatable thermal blanket (1) is stopped if a temperature difference between the outlet temperature sensor (23) and the recirculated air flow temperature sensor (7) increases above a pre-set threshold temperature difference value, wherein the pre-set threshold temperature difference value is set through the control (8) of the system by a user of the system.

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