Air supply unit and hose

Abstract

An air supply unit for forced air warming comprises a reader to identify a type of an air supply hose and a controller configured to regulate the temperature of the forced air supplied through a port to the hose depending on the length of the air supply hose. The invention also relates to a system comprising such an air supply unit and an air supply hose as well as to a method of temperature regulation of air supplied by an air supply unit such a system.

Description

[0001] Air supply unit and hose

[0002] Field of the invention

[0003] The present invention relates to the field of air supply units for forced air warming of patients in a medical context.

[0004] Background to the invention

[0005] Forced air warming units are known in different medical settings to provide air of a controlled temperature to a patient, to regulate the temperature of a patient before, during or after a medical procedure. They typically comprise a port for connection with a removably attachable hose. The air supply unit can provide air at selected, controlled temperatures through a hose, connected to the port, to a forced air patient warming device such as a blanket, underbody or medical garment connected to the other (distal) end of the hose in use. The temperature of the air supplied to the patient is of critical importance, particularly during medical procedures, but it can be difficult to control due to varying losses between the air supply unit and the patient.

[0006] It is in this context that the present invention has been devised.

[0007] Summary of the invention

[0008] In accordance with an aspect of the present invention, there is provided an air supply unit comprising: a port, a controller, and a reader, the air supply unit configured to provide temperature-regulated forced air to the port (and thereby to a connected air supply hose in use), wherein the reader is configured to identify a type of an air supply hose (connected to the port in use) from amongst types with different lengths; and the controller is configured to regulate the temperature of the forced air supplied through the port (to the connected air supply hose in use) in dependence on the length of the identified type of hose.

[0009] Air supply units typically comprise an in-built functionality that controls the temperature of air supplied by the air supply unit via a software program which can only be manually changed by a trained medical engineer. Different length air supply hoses can be connected to the air supply unit depending on the end use of the air supplied and this can lead to inaccuracies in the temperature of the air supplied to a forced air warming device (such as a blanket, underbody or garment) from the distal end of the hose (i.e. the opposite end to the end which is connected to the air supply unit). Thus, it is advantageous to regulate the temperature of the air supplied by the air supply unit to compensate for heat loss along the different lengths of the hoses.

[0010] At the present time, air temperature regulation of the air supply unit must be carried out manually after a hose has been attached to the air supply unit and so this procedure is prone to human error or is completely forgotten about. This results in a suboptimal air temperature supply at the distal end of the hose and therefore a suboptimal temperature of air that reaches a patient. By providing an air supply unit that is configured to identify a type of the hose which is connected thereto, from amongst types with different lengths; an automatic regulation of the temperature of the forced air supplied to the air supply hose can be achieved based on the length of the type of hose which is connected at any given time to the air supply unit.

[0011] Accordingly, the air supply unit is automatically able to compensate for differing heat loss on connection of hoses of different lengths. Thus, the temperature of the forced air provided through the port can be regulated in order to regulate the temperature at the distal end of a connected hose, taking into account the length of the connected hose.

[0012] This can be done, for example, by changing a temperature set point on the air supply unit without any human intervention. This makes the air supply to the patient more reliable and improves the overall performance of the air supply unit to fulfil its role of supplying air of a specific temperature to a patient.

[0013] The controller regulates the temperature set point in dependence on the length of the hose. The controller need only know the type of the hose, from amongst a plurality of different types (e.g. different sizes, different models which have different lengths etc.) and it may adjust the temperature set point in dependence on the length of the type of hose which is detected. The controller may determine the length of the hose and make a calculation as to the required temperature set point, however it may be that the controller stores different temperature set points, or other parameters related to temperature, or different temperature control algorithms, and selects the appropriate one for use in dependence on the identified type of the hose.

[0014] Typically, the reader is configured to detect an identifier of the air supply hose, wherein the identifier is dependent on the type of the hose, from amongst types with different lengths.

[0015] In some embodiments, the reader is configured to receive an electrically communicated signal from an electronically readable identifier on the air supply hose.

[0016] In some embodiments, the reader is a RFID reader. The identifier on the air supply hose may be an RFID tag (RFID transmitter or transceiver, passive or active). RFID readers are low cost, easy to incorporate into a range of materials and devices, and are efficient at the communication of information. With RFID communication, a range of frequencies can be used which can allow for a range of distances between the identifier and the reader. In some embodiments, the RFID reader is a low frequency reader. The operating frequency of the low frequency reader may be, for example, from between 100 - 150 kHz. By operating the RFID reader at low frequency, minimal interference with other equipment in an environment, for example, in a medical setting such as a hospital ward or an operating theatre. In some embodiments, the RFID reader is a high frequency reader. The operating frequency of the high frequency RFID reader may be between 10 - 20 MHz, for example 13.56 MHz. Using a high frequency reader enables the communication of the reader with the identifier over larger distances whilst still maintaining a strong communication link.

[0017] However, the identifier of the air supply hose may be another type of identifier. For example, different types of hose may comprise identifiers such as magnets, visual markings or electrical connections, in different locations or providing different readable data depending on the type of the hose, and the reader may detect the position of the identifier, or read the readable data, respectively. In some embodiments, the port comprises a receiving portion and the hose comprises a complementary formation which is complementary to the receiving portion, such as to cause the hose to connect with the port in a specific position and orientation. The position of the identifier relative to the complementary formation may be indicative of the type of the hose. It may be that the when the complementary formation mates with the receiving portion, data is read from the identifier of the hose.

[0018] In some embodiments, the receiving portion and complementary formation are a projection on the air supply hose and a complementary receiving groove or notch on the reader, or vice versa. The receiving portion may be located inwardly of the port or on an exterior wall of the port. For example, the receiving portion may be a notch that extends along an outer circumference of the port.

[0019] In some embodiments, the controller regulates the temperature of the air supplied through the port by selecting a temperature set point. The temperature set point can be automatically controlled by the air supply unit depending on the length of the hose attached to the air supply unit. When a longer hose is attached, the air supply unit can automatically increase the temperature set point to compensate for the heat loss through the hose before reaching the patient. This provides a highly efficient way of ensuring a patient is provided with an optimal temperature air supply.

[0020] In some embodiments, the temperature setpoint is selected in dependence on a rate of airflow through the port into the supply hose. The temperature of the air supplied by the air supply unit, and the amount of heat lost within the hose, can be affected by the rate of airflow. The air supply unit can automatically adjust a temperature setpoint based on this airflow rate which provides an efficient supply of optimal temperature air to the patient.

[0021] In some embodiments a user selects or inputs a target temperature to the air supply unit. This is typically a target for the temperature of air at the distal end of the hose, where it enters a forced air warming device in use. The air supply unit may compensate for the temperature difference between a temperature set point inputted by the user which is displayed on the air supply unit and the actual temperature of the forced air supplied to a hose end which is proximal to a patient by increasing the temperature set point relative to the user inputted set point. For example, if a user sets the air supply unit temperature to 37 °C, when a short hose is attached, for example a 1 ,8m hose, the air supply unit may adjust the temperature set point to 37.5 °C and when a longer hose (relative to the short hose) is used, for example a 3m hose, the air supply unit may adjust the temperature set point to 38.5 °C to compensate for heat loss along different lengths of the hose attached.

[0022] In accordance with a further aspect of the invention, there is provided a system comprising: an air supply unit according to any of the above-mentioned embodiments; and an air supply hose, wherein the air supply hose comprises an identifier which is indicative of the type of the hose.

[0023] By providing a system comprising the air supply unit able to identify the type of air supply hose connected thereto, and therefore determine the length of the hose, the temperature regulation of the air supplied by the air supply unit to the air supply hose can be achieved without any human intervention and thus reduce any human error in air supply temperature regulation as it is automatically controlled.

[0024] In some embodiments, the identifier is an electronically readable identifier.

[0025] In some embodiments, the identifier is a RFID identifier. In some embodiments, the identifier is a low frequency RFID identifier. In some embodiments, the identifier is a high frequency RFID identifier.

[0026] In some embodiments, the receiving portion and identifier are complementary formations.

[0027] In some embodiments, the identifier is a curved projection that extends along an outer circumference of the air supply hose.

[0028] In some embodiments, the identifier is integrated into the hose. In some embodiments, the identifier is removably attached to the hose.

[0029] In accordance with a further aspect of the invention, there is provided a method of temperature regulation of air supplied by an air supply unit within a system according to any of the above-mentioned embodiments to an air supply hose connected thereto, the air supply hose comprising an identifier which is indicative of the type of the hose, the method comprising the steps of: connection of the air supply hose to the air supply unit; identification of the type of the hose by the air supply unit on connection of the air supply hose to the air supply unit; and regulation of the temperature of the air supplied to the air supply hose in dependence on the length of the identified hose.

[0030] Description of the Drawings

[0031] An example embodiment of the present invention will now be illustrated with reference to the following Figures in which:

[0032] Figure 1 is a perspective view of a system according to an embodiment of the invention.

[0033] Figure 2 is a perspective view of a system according to an embodiment of the invention.

[0034] Figure 3 is a flowchart of a method according to an embodiment of the invention.

[0035] Detailed Description of an Example Embodiment

[0036] Figure 1 shows a system 100 in accordance with an embodiment of the invention, during operation. The system 100 comprises an air supply unit 110 comprising a port 120, a low frequency RFID reader 160, a controller 130, a heater 170 and a temperature sensor 180. The controller 130 is in electrical communication with both the reader 160 and the heater 170. An air supply hose 140 is connected to the air supply unit 110 via the port 120. The air supply hose comprises a passive low frequency RFID tag 150, functioning as the identifier of the type of the hose, which can communicate wirelessly with the low frequency RFID reader 160 that is located in the air supply unit 110. When the air supply hose 140 is connected to the air supply unit 110, the distance between the identifier 150 and the reader 160 is approximately 5 cm. This enables a reliable RF connection between the two devices operating at low frequency.

[0037] When the hose 140 is connected to the air supply unit 110, the reader 160 queries the RFID tag 150. The RFID tag 150 responds with data including data indicating a type of the hose, for example a part number, model number etc. The reader 160 transmits this signal to the controller 130 and the controller 130 then controls the heater 170 to a temperature set point which depends on the length of the identified type of hose, using feedback from the temperature sensor 180 to ensure accurate control.

[0038] It would be possible for the data received from the RFID tag 150 to include data specifying the length of the hose (being an example of a type of a hose from amongst types with different lengths) and for the controller 130 to receive that length data, make calculations relating to expected heat loss for a hose of that length and to adjust the temperature setpoint as a result. However, in practice it is sufficient for the controller 130 to receive information about the type of hose from the reader 160 and to adjust the temperature setpoint depending on the length of that type of hose. This may be implemented as simply as by the controller 130 having a memory storing a plurality of temperature setpoints for different values of the type identifier data which may be received from the RFID tag 150 via the reader 160 and selecting the appropriate set point to use to set the temperature setpoint.

[0039] Alternatively, the controller may use a different temperature regulation algorithm for different values of type identifier data. Instead of storing temperature setpoints in numerical terms, it is also possible store temperature differences and to set the temperature setpoint to a temperature which differs from a requested target temperature by the respective temperature difference. Thus the invention can function where the user can select from a continuous ranges of target temperature.

[0040] As a result of the invention, when a longer hose 140 is attached, for example a 3m hose, the temperature set point of the air supply unit 110 is increased to a predetermined amount higher than the target air temperature at the distal end of the hose, to compensate for heat loss along the length of the hose 140. Similarly, when a shorter hose 140 is used, for example a 1 ,8m hose, the temperature set point is set to a temperature which is still higher than the target air temperature at the distal end of the hose, but by a lower amount, as less compensation is required for heat loss, due to the shorter hose.

[0041] Figure 2 shows an alternative system 200 in accordance with an embodiment of the invention. The system 200 comprises an air supply unit 210 comprising port 220, controller 230, reader 260, heater 270 and temperature sensor 280. The controller is in electrical communication with both the reader 260 and the heater 270. The reader 260 comprises receiving portions 261 , 262. Receiving portion 261 is a pair of curved notches located along the circumference of the port 220. Receiving portion 262 is a pair of elongate rectangular notches located along an inner region of the port 220. The air supply unit 200 is therefore configured to attach two different hoses of different lengths 241 , 242. Air supply hose 241 comprises a pair of projections 243 which are of complementary dimensions to be specifically received by the receiving portion 261 on the air supply unit. Air supply hose 242 comprises a pair of projections 244 which are of complementary shape to be received by the receiving portion 262 on the air supply unit.

[0042] The specific projection of the air supply hose 241 , 242 connects with the complementary receiving portion 261 , 262. Described below is the connection between air supply hose 241 and the air supply unit 210; however, it will be understood that the same working principle applies to connection of air supply hose 242 with the air supply unit 210.

[0043] On connection of air supply hose 242 to the air supply unit 210, projections 244 are inserted into receiving portion 261 and secured into place by a locking mechanism which closes a circuit (not shown). The closure of the circuit relays a signal which is indicative of the type of air supply hose 241 to the controller 230. The controller 230 again regulates the temperature of the air supplied to the hose 241 by the air supply unit 210 by adjusting a temperature set point of the air supply unit 210 depending on the length of air supply hoses of that type.

[0044] Figure 3 shows the steps of a method of temperature regulation 300 in accordance with the invention. A first step 310 is the connection of the hose to the air supply unit. A second step 320 is identification of the type of the hose by the air supply unit on connection of the hose to the air supply unit. A third step 330 is regulation of the temperature of the air supplied to the air supply hose which takes into account the identified type of the hose and is adapted to compensate for the length of hoses of that identified type.

[0045] Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to and do not exclude other components, integers, or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0046] Features, integers, characteristics, or groups described in conjunction with a particular aspect, embodiment, or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

Claims1. An air supply unit comprising:- a port,- a controller, and- a reader, wherein the air supply unit is configured to provide temperature-regulated forced air to the port, wherein the reader is configured to identify a type of an air supply hose, from amongst types with different lengths, and wherein the controller is configured to regulate the temperature of the forced air supplied through the port in dependence on the length of the identified type of hose.

2. An air supply unit according to claim 1 , wherein the reader is configured to detect an identifier of the air supply hose, wherein the identifier is dependent on the type of the hose.

3. The air supply unit according to claim 1 or claim 2, wherein the reader is able to receive an electrically communicated signal from an electronically readable identifier on the air supply hose.

4. The air supply unit according to claim 3, wherein the reader is a RFID reader.

5. The air supply unit according to any one of the preceding claims, wherein the port comprises a receiving portion and the hose comprises a complementary formation which is complementary to the receiving portion, such as to cause the hose to connect with the port in a specific position and orientation.

6. The air supply unit according to any one of the preceding claims, wherein the controller regulates the temperature of the air supplied through the port by selecting a temperature set point.

7. The air supply unit according to claim 6, wherein the temperature setpoint is selected in dependence on a rate of airflow through the port into the supply hose.

8. A system comprising: an air supply unit according to any one of claims 1 to 7; and an air supply hose, wherein the air supply hose comprises an identifier which is indicative of the type of the hose.

9. The system according to claim 8, wherein the identifier is an electronically readable identifier.

10. The system according to any one of claims 8 to 9, wherein the identifier is a RFID identifier.11 . The system according to claim 8, wherein the receiving portion and identifier are complementary formations.

12. The system according to claim 11 , wherein the identifier is a curved projection that extends along an outer circumference of the air supply hose.

13. The system according to any one of claims 8 to 12, wherein the identifier is integrated into the hose.

14. The system according to any one of claims 8 to 12, wherein the identifier is removably attached to the hose.

15. A method of temperature regulation of air supplied by an air supply unit within a system according to any one of claims 8 to 14 to an air supply hose connected thereto, the method comprising the steps of:- connecting the air supply hose to the air supply unit;- identifying the type of the hose by the air supply unit on connection of the air supply hose to the air supply unit; and- regulating the temperature of the air supplied to the air supply hose in dependence on the length of the identified type of hose.

Images