JP3053871B2 - Operating table air mat - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an air mat, and more particularly to an air mat for an operating table.

BACKGROUND ART When a person sleeps on a bed, the lower surface of the human body in contact with the bed receives the gravity of the human body present thereon. Circulatory organs, such as blood vessels, lymph vessels, etc., are compressed and reduce their function.
In the case of a healthy person, he or she rolls over to change the place where pressure is exerted by gravity and maintain the function of the circulatory system normally.

However, a person who cannot turn over on his own, such as a bedridden elderly person or an anesthetized patient, stays on the bed in the same posture. When a person sleeps on the bed in the same posture for a long time, the lower part of the human body in contact with the bed reduces the circulation function by compression by gravity,
Causes pressure sores. In order to prevent pressure ulcers, it is necessary to prevent pressure (body pressure) from being applied to the same part of the human body for a long time.

Air mats that can prevent pressure sores have been developed. An air mat is constituted by a plurality of sets of air cells, and compressed air is selectively supplied to the set of air cells. When the compressed air supply is intermittent, the surface part of the human body in contact with the organ air mat to which the compressed air is not supplied is released from the body pressure, and the function of the circulatory system is restored.

For example, a surface on which a person lies is formed by an air mat composed of a large number of air cells, the air cells are divided into two sets, and compressed air is alternately supplied to the two sets of air cells. Then, even in a human body sleeping in the same posture on the air mat, a place where the human body receives the body pressure changes. Since the place where the body pressure is received is changed, it is possible to prevent pressure sores.

With such an air mat, the nursing care labor of a person who cannot move himself by himself, such as a bedridden elderly person, is greatly reduced.

By the way, in an operation, a patient who undergoes an operation receives anesthesia or the like, and cannot change his or her own posture. Also, the posture of the patient must be kept the same for the doctor performing the operation. In order to prevent pressure ulcers in patients undergoing surgery, an air mat that can change the place where the weight of the patient is supported is extremely effective.

During surgery, the doctor moves the body for surgery and raises the body temperature. When the operating room temperature is high, the doctor sweats,
There is a risk that sweat will fall on the affected area of the patient. For this reason,
The room temperature of the operating room is usually cooled to about 22 to 25 ° C.

By the way, the patient who undergoes the operation keeps the same posture during the operation. In many cases, patients are anesthetized, reducing their vital activity. If a patient is left in a cooled room for a long time, the patient's body temperature will decrease. Patients whose body temperature has decreased during surgery will lose their physical strength. If the physical strength of a patient who has undergone surgery decreases, it will hinder recovery of physical strength after surgery.

Therefore, it is desirable to maintain the body temperature of a patient undergoing surgery at a predetermined level.

Japanese Utility Model Publication No. 60-129918 discloses an air mat in which a cord heater is arranged at a connection portion between adjacent air cells. The air cells are formed of a sheet of rubber or synthetic resin and are arranged adjacent to each other to form a bed surface. There is a gap between adjacent air cells and the cord heater is located in this gap.

However, when the air mat having this configuration is used as an operating table air mat, the following problems occur. During surgery, the patient maintains a constant position. For the convenience of the surgeon performing the surgery, the thickness of the air mat for the operating table cannot be increased. When the local heating is performed by the code heater, it is not easy to uniformly heat the patient's body. Temperature distribution tends to occur on the patient's body surface. It is desired that more uniform heating can be performed.

Further, in order to recover a patient's body temperature that has decreased during the operation, a body temperature recovery device that covers the patient's body after the operation and sends heated air inside has been developed.

DISCLOSURE OF THE INVENTION An object of the present invention is to provide an operating table air mat that can prevent a decrease in body temperature without causing pressure ulcers in patients undergoing surgery.

Another object of the invention is to prevent pressure ulcers in patients during surgery,
It is an object of the present invention to provide a method of operating an operating table air mat capable of preventing a decrease in body temperature.

According to one aspect of the invention, there are a plurality of groups of air cells arranged on a longitudinally extending bed surface, each air cell being formed of a deformable bag-shaped sheet and having an air-permeable opening. A plurality of groups of air cells that can cooperate to form a resilient support surface on which a patient undergoing surgery is placed on the upper surface; and A sheet heater having a sheet-like shape having an area including a main part of a body; a deformable bag enclosing the sheet heater and the plurality of groups of air cells; And a temperature sensor for generating a temperature signal representing the detected temperature T, and a group of air cells that do not supply air can be sequentially replaced. Selection Manner and the air supply means, receiving said temperature signal, based on the detected temperature, air mat device for operating table and a control unit for controlling the power supply to the planar heater is provided.

According to an aspect of the present invention, there is provided a method for operating an operating table air mat capable of periodically changing a patient's weight holding surface, wherein the heater provided on the lower surface of the air layer of the air mat is operated to generate heat. Heat generation step, a step of measuring the temperature T _i by a sensor provided on the upper surface of the air layer of the air mat, and comparing the measured temperature T _i with a comparison temperature (T ₀ −ΔT ₁ ) lower than the target temperature T ₀ by ΔT _1. And the measured temperature T _i
Reducing the driving current of the heater when the temperature reaches the comparison temperature (T ₀ −ΔT ₁ ).

Since the heater has a sheet-like planar shape corresponding to the main part of the patient, surface heat can be uniformly generated. The main part of the patient's body refers to an area including at least the torso of the patient's upper body. In addition, the heater is located below the air layer, and heat is transferred to the patient above it through the air layer, thus allowing for more uniform patient warming. Although there is a time lag between the temperature change of the heater and the temperature change of the upper surface of the air layer, high-precision temperature control becomes possible by measuring the temperature on the upper surface of the air layer and performing predictive control.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially broken plan view of an air mat according to an embodiment of the present invention.

 FIG. 2 is a sectional view taken along the line II-II in FIG.

 FIG. 3 is a plan view of a heater portion of the air mat.

FIG. 4 is a plan view showing the arrangement of a heater portion and a heater temperature detection sensor of the entire air mat.

FIG. 5 is a block diagram showing a heater control circuit of the air mat.

FIG. 6 is a more detailed block diagram of the heater control circuit of the air mat.

FIG. 7 is a graph for explaining the synthesis temperature control in the air mat.

FIG. 8 is a flowchart showing an example of the control of the synthesis temperature of the air mat.

FIG. 9 is a flowchart illustrating another example of controlling the synthesis temperature of the air mat.

FIGS. 10A and 10B are flowcharts showing another example of air mat synthesis temperature control.

FIG. 11A is a sectional view of an air mat according to another embodiment of the present invention.

 FIG. 11B is a plan view of the air mat of FIG. 11A.

12A to 12C are a front view, a partial front view, and a back view of the heater control device for the air mat.

FIG. 13 is a graph showing the body temperature holding performance of the air mat according to the embodiment of the present invention.

14A to 14E are schematic side views and graphs for explaining a preliminary experiment on which the present invention is based.

BEST MODE FOR CARRYING OUT THE INVENTION In surgery, a patient is required to maintain a certain position, especially in a long-time surgery requiring 3 hours or more.
May cause pressure ulcers and lower body temperature. Under general anesthesia, patients cannot move their own body. In addition, for a doctor who performs surgery, movement of a patient's body hinders operation for surgery.

Thus, the patient's body is maintained in a constant position during the operation. When sleeping in a constant posture for a long time, the function of the circulatory system is reduced on the lower surface of the body of a patient receiving weight, and pressure ulcers occur.
An air mat is used to prevent this pressure sore.

The air mat is composed of a plurality of air cells. The air cell filled with air and the air cell whose air pressure is released are mixed, and the weight of the patient is borne only by the air cell filled with air. The body pressure can be dispersed by replacing the air cells that have released the air pressure. In this manner, pressure ulcers can be prevented by periodically changing the air cells that receive the weight of the patient.

By the way, during the operation, the room temperature of the operating room is maintained at about 22 to 25 ° C., for example, about 23 ° C., to prevent the doctor from sweating. Patients undergoing surgery will be left at this low temperature for a long time with reduced physical activity. Therefore, the patient's body temperature during the operation decreases, and tremors and the like occur due to the decrease in the body temperature after the operation.

In order for a patient who undergoes surgery to properly recover physical strength after surgery, it is preferable to maintain the patient's body temperature at an appropriate temperature during surgery. As means for maintaining the patient's body temperature, use of an electric sheet or an electric blanket may be considered.

14A-14E show preliminary experiments for pressure ulcer prevention and body temperature maintenance at the operating table.

FIG. 14A shows an experimental apparatus. An operating table 51 is placed on the floor 50, and a normal mat 52 is placed on the operating table 51. The measuring device comprises a pressure-sensitive element 56 and a weight 58 disposed thereon.
It is. The pressure-sensitive element has a diameter of 9 mm, and the weight 58 is 12 kg. The operating table 51 is usually about 45 to 50 cm wide and 190 to 192 cm long
Have a degree.

FIG. 14B shows a measurement result when the pressure-sensitive element 56 and the weight 58 are directly arranged on the mat 52. The horizontal axis shows elapsed time,
The vertical axis shows the normalized pressure received by the pressure-sensitive element. When the pressure-sensitive element 56 and the weight 58 are directly placed on the air mat 52, the pressure received from the weight 58 slightly decreases with the passage of time, but becomes approximately 93% after 15 minutes, and hardly changes thereafter. If the patient continues to receive a constant body pressure, a pressure ulcer is formed on the patient's body.

Then, next, the air mat 54 was arranged on the mat 52, and the two sets of air cells in the air mat were alternately urged to distribute the body pressure.

FIG.14C arranges a pressure-sensitive element 56 on an air mat 54,
The measurement result when the weight 58 is arranged thereon is shown. When the air cell under the pressure sensing element 56 is filled with air,
The pressure of 58 is applied to the pressure-sensitive element 56, and when the air pressure of the air cell below the pressure-sensitive element 56 is released, the pressure received by the pressure-sensitive element is greatly reduced.

In the results shown, the pressure when the air pressure is applied to the air cell is about 98%, and when the pressure is released, the pressure received by the pressure-sensitive element 56 is reduced to about 8%. Thus, releasing the body pressure restores the function of the circulatory system and is effective in preventing pressure ulcers.

Further, in order to maintain the body temperature of the patient during the operation, a sheet-like heat retaining member was placed on the mat 54, and the same experiment was performed.

FIGS. 14D and 14E show two types of heat insulating sheets using air mat 54.
The results of an experiment in which the pressure-sensitive element 56 and the weight 58 are placed on the top and the pressure-sensitive element 56 and the weight 58 are shown. When the air cell under the pressure-sensitive element is filled with air and bears the pressure of the weight 58, both values are about 90
%, About 30 to 40% of the load remains even when the air is released from the air cell and the load is released. That is, when the heater sheet for maintaining body temperature is arranged on the air mat 54, the load releasing effect of the air mat is greatly reduced.

The present inventor has developed an operating table air mat that can maintain a patient's body temperature without losing the load distribution effect of the air mat based on the above experimental results.

1 to 5 schematically show the structure of an air mat according to one embodiment of the present invention. FIG. 1 is a partially cutaway plan view of the air mat, and FIG. 2 is a sectional view taken along line II-II of FIG. The air mat 1 includes a parallel arrangement of a number of air cells 1b extending in the lateral direction of the bed. Each air cell 1b
An elongated bag made of synthetic resin such as vinyl chloride, one end of which is closed and the other end is open.

The closed end extends and forms a support piece 1c. The open ends are alternately connected to the air supply pipes 2a, 2b.
A support sheet 1a made of a synthetic resin such as polypropylene or vinyl chloride is disposed below the air cell 1b.
The air cell 1b is connected to the air cell 1b by a locking means 1d such as a hook disposed on the closed end side.

Two air supply pipes 2a and 2b extend from the pump P arranged outside the bed to the open end side of the air cell 1b, and are alternately connected to the air cell 1b. That is, every other air cell 1b is connected to the same air pressure source. In a state in which pressurized air is supplied to the first set of air cells 1b,
The air pressure in the second air cell 1b is released, and then the second set of air cells is also supplied with pressurized air. After the second set of air cells is fully pressurized, the pressure in the first set of air cells is released.

Next, while the second set of air cells is in a pressurized state, pressurized air is also supplied to the first set of air cells whose air pressure has been released. After the first set of air cells is fully pressurized,
Relieve the pressure in the second set of air cells. By doing so, it is possible to periodically change the load location while keeping the body position of the patient constant.

In order to keep the patient in a constant position and not hinder the physician's surgical operation, the diameter of each air cell under pressure should be approximately 4
About 8 cm is preferred. In particular, it is preferable to make the diameter of the air cell smaller in the center of the bed that receives the main part of the patient's body. For example, the air cell at the center of the bed is about 5 cm in diameter, and the air cells at both ends of the bed are about 6.5 cm in diameter.
cm. The diameter ratio between the small diameter cell and the large diameter cell is 1.25 to 1.35
Position is preferred.

A heater is arranged adjacent to the lower side of the air mat 1 to maintain the patient's body temperature. In order to perform uniform heating,
A surface heater that generates heat on the entire surface on which the heater is arranged is used. As shown in FIG. 2, a carbon heater layer 3 containing carbon and silver is formed on the upper surface of a polypropylene sheet 4 having excellent insulation, heat resistance, and heat insulation.
An air mat 5 with a heating function is constituted by the air cell 1b, the support sheet 1a, the carbon heater layer 3, and the support sheet 4. The air mat with heating function 5 is housed in a bag 6. The bag 6 has a layer 6a of an infrared reflective material such as aluminum on the inner surface of a synthetic resin sheet 6b made of polyester or the like having excellent heat resistance, heat retention and waterproofness.

As shown in FIG. 3, the carbon heater layer 3 is formed on almost the entire surface of the support sheet 4. Substantially the entire surface refers to the degree to which an empty area in the manufacturing process is left around. Accordingly, the carbon heater layer 3 can substantially uniformly heat a wide area of the bed surface including the area supporting the patient's body. A temperature detecting element 10 such as a thermistor is disposed at the center of the upper surface of the carbon heater layer 3. This temperature detecting element 10 is a carbon heater layer 3
Detects its own temperature.

As shown in FIG. 3, the carbon heater layer 3 has an electrode 3a along its long side, and current flows in parallel with the short side.

A thin, high-precision temperature detecting element 9 such as a semiconductor temperature sensor is embedded in the upper surface of the bag 6. The temperature detecting element 9 detects a combined temperature of a body temperature of a human body disposed thereon and a temperature of an air layer disposed thereunder.

As shown in FIG. 4, a planar heater may be formed on the entire bed surface in two parts. The support sheet 4 can be folded in two in the longitudinal direction,
A polygonal line 7a is formed and is divided into portions 4a and 4b on both sides thereof. The carbon heater layers 3a and 3b described above are formed on the surfaces 4a and 4b of the support sheet. One carbon heater layer 3a can heat the area including at least the torso of the upper body of the patient, and the entire carbon heater layers 3a and 3b can heat the area including substantially the whole body of the patient. These carbon heater layers 3a and 3b are electrically connected by a flexible conductor 8a that is strong against bending. Temperature detecting elements 10a and 10b such as thermistors are arranged at the center of each of the carbon heater layers 3a and 3b.

FIG. 5 schematically shows an electric circuit of a bed including the above-described heater. The power supply 11 is connected to the control circuit 12 via the switch 14. The planar heater 3 is connected to the control circuit 12 via a fuse 13. The fuse 13 is a thermal fuse, and is disconnected when an abnormally high temperature occurs. Further connected to the control circuit 12 are a temperature detecting element 10 for a heater and a sensor 9 for detecting a combined temperature of the body temperature and the temperature of the air layer. The control circuit 12 controls the driving power of the planar heater by comparing the set temperature with the combined temperature.

In the configuration of FIG. 5, each of the heaters 3a,
A control circuit may be provided for each 3b, or one control circuit may be provided for the entire heaters 3a and 3b. In addition, heater 3
a and 3b may be connected in parallel or in series. Note that the heater may be configured as a single unit without being divided into a plurality. Further, the heater can be divided into three or more portions.

Next, the operation of the above-described air mat will be described. By driving the air pump P shown in FIG. 1, the air mat 1 is expanded to a usable state.

In the circuit shown in FIG. 5, when the power switch 14 is turned on, the sheet heater 3, the combined temperature detecting sensor 9 and the heater temperature detecting sensor 10 are all turned on via the control circuit 12. The planar heater 3 generates heat and raises the temperature of the air mat to a predetermined temperature. When the combined temperature detecting sensor 9 on the surface of the bag 6 detects the set temperature, the drive current of the planar heater 3 is turned off. When the combined temperature decreases, a current is again supplied to the planar heater 3 to perform a temperature raising operation. As described above, the heating operation is repeated while detecting the combined temperature, and the body temperature of the person lying on the bag 6 is heated to the predetermined temperature.

When the heater temperature sensor 10 detects a temperature equal to or higher than a predetermined temperature during heating of the heater 3, it is determined that abnormal heating has occurred, and the drive current of the heater 3 is turned off. When the heater temperature falls below the predetermined temperature, the drive current of the surface heater 3 may be turned on again. When an abnormal temperature rise is detected,
If the operator does not reset the power supply after determining the cause of the abnormal temperature rise and resolving it, the drive current can be prevented from flowing.

The set temperature can be selected in the range of 35 to 42 ° C. If the temperature of the part in contact with the human body rises above 39 ° C, there is a danger of causing a low-temperature burn to the patient. In order to prevent low-temperature burns, it is preferable to arrange a plurality of sensors for detecting the synthesis temperature along the expected main part of the human body and control each synthesis temperature to 39 ° C. or lower.

FIG. 6 is a block diagram showing details of the control circuit. 2
The two planar heaters 3a and 3b are arranged along the bed surface, and temperature detecting sensors 10a and 10b are arranged respectively.
The planar heater is heated to, for example, about 70 ° C. The temperature detecting sensor is provided to detect a temperature significantly higher than the heater temperature. The drive current for the planar heaters 3a, 3b is supplied from a current supply source 11 via thermal fuses 13a, 13b. When the temperature of the sheet heater 3 becomes abnormally high, the temperature fuse 13 is disconnected and cuts off the drive current.

The power supply source 11 can selectively supply power to each of the planar heaters 3a and 3b, and can also supply a driving current to the planar heaters 3a and 3b at the same time. The operation of the power supply source 11 is controlled by the control circuit 12.

In the operating room, usable voltage is often limited in order to prevent noise on an electrocardiogram or the like. For example,
Only AC up to 20V and DC up to 50V are available. It is preferable to use a direct current in order to generate more heat with the same resistance heater. Hereinafter, description will be made assuming that a series drive current is supplied to the planar heater.

The control circuit 12 is constituted by a central processing unit CPU, and detects detection signals from the combined temperature detection sensors 9a and 9b, a target temperature signal input from the key 16, a start / off instruction signal input from the key 19, and the like. Receive.

The detection signals from the combined temperature detection sensors 9a and 9b are converted into voltage signals via current / voltage conversion circuits 13a and 13b, and supplied to the selection circuit 21 in the control circuit 12. The selection circuit 21
The two temperature signals are periodically supplied to the conversion circuit 22. The conversion circuit 22 calculates the temperature T measured from the temperature detection signal, and causes the temperature display 15 to display the averaged detected temperature,
A temperature detection signal is supplied to the control block 24.

The selection circuit 21 also outputs the detected temperature signal to the abnormality detection circuit.
Supply 23. When detecting an abnormally high temperature, the abnormality detection circuit 23 supplies an abnormality detection signal to the protection circuit 28 immediately. The protection circuit 28 controls the power supply source 11 to
The power supply to 3a and 3b is stopped.

The abnormality detection signal is sent from the abnormality detection circuit 23 to the control block 24.
Also sent to. The control block 24 stops the normal control during the abnormality detection.

Similarly, an electrosurgical or laser scalpel device in the operating room
From 40, a knife use signal is supplied to the abnormality detection circuit 23. Since strong noise is generated while the scalpel is being used, the abnormality detection circuit 23 generates an abnormality detection signal and stops driving the planar heater, similarly to the case of detecting an abnormally high temperature. As shown by a broken line, a female use signal and the protection signal may be directly supplied to the protection circuit 28.

The target temperature T ₀ set by the key 16 is displayed on the set temperature display 17 and is supplied to the control block 24. The key 19 gives a signal for instructing power supply to the planar heaters 3a and 3b.

Control block when heating operation is turned on by key 19.
24 compares the measured temperature T sent from the conversion circuit 22 with the target temperature T ₀ , performs a predetermined calculation, and generates an instruction signal to the heater prediction control circuit 25. The heater prediction control circuit 25
The power supply source 11 is controlled while predicting a change in the detected temperature.

FIG. 7 is a graph for schematically explaining the prediction control. The horizontal axis indicates time t, and the vertical axis indicates synthesis temperature T.
The target temperature to be set by a key 16 and T _0.
The combined temperature T gradually increases due to the heat generated by the planar heaters 3a and 3b, and the comparison temperature T ₀ − which is lower by ΔT ₁ than the target temperature T _0.
When ΔT ₁ is reached, power supply to the planar heater is stopped. At this time, the planar heater has a temperature of, for example, 70 ° C. and is higher than a synthesis temperature T of, for example, 38 ° C. Even if the drive current to the planar heater is cut off, the combined temperature T continues to rise for a while. Therefore, the comparative temperature T ₀ −ΔT ₁ is set in consideration of the overshoot of this temperature rise. When the supply of electric power to the planar heater is stopped, the temperature rise gradually becomes gentle, eventually saturates, and then begins to fall.

Detection synthetic temperature T, also supplies a drive current again to the heater when it reaches the target temperature T ₀ descends, synthesis temperature T is not immediately recovered. There is also a time delay before the amount of heat generated from the planar heater affects the synthesis temperature. Then, after the supply of the driving current to the planar heater is stopped and the temperature rise is saturated, the temperature becomes T ₀ +
When it becomes lower than ΔT _2, the driving of the planar heater is restarted. Even if the driving of the planar heater is restarted, the combined temperature decreases for a while, and then the temperature starts to rise due to the heat generated by the planar heater. Thus, by predicting a change in synthesis temperature, controls the synthesis temperature T in the vicinity of the target temperature T _0.

In addition, at the time of the initial temperature rise, it is preferable that a relatively large current is applied and heating is performed rapidly in order to raise the temperature to the set temperature in a short time. In this case, since the overshoot of the synthesis temperature also becomes large, ΔT ₁ is set to be relatively large.

Once the synthesis temperature T after reaching the vicinity of _zero target temperature T, in order to improve the accuracy of the temperature control, the drive current to the plane heater is preferably lower than the initial drive current. In this case, the comparison temperature T ₀ −ΔT ₃ of the drive current restart is:
It is preferable to set higher than the initial comparative temperature T ₀ −ΔT ₁ . [Delta] T _2, if set small [Delta] T _3, the synthesis temperature T can be controlled within a narrow temperature range around the target temperature T _0. However, the drive current may be one type, and ΔT ₁ and ΔT ₃ may be the same.

FIG. 8 shows a flowchart of the temperature control when the drive current is one type. When control starts, first step
Power is supplied in S1, and the planar heaters 3a and 3b generate heat. Next, in step S2, the synthesis temperature T is measured. In addition,
Measurements order to be periodically repeated, and the detected temperature T of a certain moment T _i.

A plurality of measurements may be calculated T _i by averaging. If there are a plurality of combined temperature detecting sensors, a higher combined temperature or an average value is used.

Next, in step S3, it is determined whether or not power is on. When being power-on, the process proceeds to step S4 follows an arrow Y, the detected temperature T _i is compared temperature (T ₀ -ΔT ₁₎
It is determined whether it is greater than. Since the determination is negative until the combined temperature T reaches the comparison temperature (T ₀ −ΔT ₁ ), the process returns to step S2 according to the arrow N to continue heating.

When the detected temperature T _i is higher than the comparison temperature (T ₀ -ΔT _1), the process proceeds to step S5 follows an arrow Y, to turn off the drive current to the plane heater. After turning off the drive current to the planar heater, the process returns to step S2 to detect the combined temperature. The synthesis temperature continues to rise for some time with residual heat.

In a state where the power is cut off, the determination in step S3 is negative, and the process proceeds to step S6 according to the arrow of N. Steps
In S6, the difference (T _i −T _i−1 ) between the current detected temperature T _i and the previous detected temperature T _i−1 is calculated, and is set as ΔT _i .

Next, in step S7, it is determined whether ΔT _i has become 0 or negative. When ΔT _i becomes 0 or a negative value, it indicates that the temperature rise ends and the temperature falls thereafter. Therefore, the process proceeds to step S8 according to the arrow Y.

In step S8, the detected temperature T _i is set to the comparison temperature (T ₀ −ΔT ₂ ).
It is determined whether it is lower than. The detected temperature is the comparison temperature (T ₀
If the temperature is lower than −ΔT ₂ ), it means that the combined temperature will be lower than the target temperature T ₀ soon. Therefore, the process proceeds to step S9 according to the arrow Y, and power is supplied to the planar heater. Then, the process returns to step S2.

After the power is turned off, if the temperature change ΔT _i is positive in step S7, the temperature rise is still spelled out, and the process returns to step S2 according to the arrow N. Similarly, in step S8, the temperature rise has ended, but if the detected temperature T _i is higher than the comparison temperature (T ₀ −ΔT ₂ ), the drive current will be higher than the target temperature when the drive current is turned on again. , N, and returns to step S2.

Thus, by providing the temperature change prediction widths ΔT ₁ and ΔT ₂ with the target temperature T ₀ interposed therebetween and predicting the change in the combined temperature, temperature control with little overshoot can be performed.

FIG. 9 shows another example of temperature control for performing more precise control. The control starts. In step M1, electric power P1 is supplied, and heating of the planar heater starts. This electric power P1 is set to a large value in order to heat the air mat to a predetermined temperature in a short time.

Next, in step M2, the temperature _Ti is detected. In Step M3, it is determined whether or not the detected temperature Ti has become higher than the comparison temperature (T ₀ −ΔT ₁ ). The detected temperature Ti is the comparison temperature (T ₀
If it is not higher than -ΔT ₁ ), it is determined that heating is still necessary, and the process returns to step M2 according to the arrow of N.

When the detected temperature Ti becomes higher than the comparison temperature (T ₀ −ΔT ₁ ), it is determined that sufficient heating has been performed to reach the target temperature T ₀ , and the process proceeds to step M 4 according to the arrow Y, and the power P 1 Sever.

After refused power supply, again it detects periodically synthesis temperature T _i in step M5. In step M6, a difference (T _i −T _i−1 ) between the present detection temperature T _i and the previous detection temperature T _i−1 is obtained, and is set as ΔT _i .

In the next step M7, it is determined whether ΔT _i has become 0 or negative.

When ΔT _i becomes 0 or negative, it means that the synthesis temperature will decrease thereafter.

When ΔT _i becomes 0 or negative, the process proceeds to step M8 according to the arrow Y, and it is determined whether the detected temperature T _i is lower than the comparison temperature (T ₀ −ΔT ₂ ). The detected temperature _Ti is the comparison temperature (T ₀ −
If it is lower than ΔT ₂ ), follow the steps according to the arrow of Y
Proceed to M9 to determine whether power is on or off. If the power has been cut off, the process proceeds to step M10 according to the arrow Y, and the power P2 is supplied. Then step M5
Return to The planar heater resumes heat generation so that the combined temperature does not become too low. Electric power P2 is set to P1 to keep it warm.
It is selected smaller.

Incidentally, the detected temperature T _i is compared temperature in step M8 (T ₀ -Δ
If not lower than T ₂ ), it is not necessary to restart the heat generation yet, so the flow returns to step M5 according to the arrow of N. If the power has not been cut off in step M9, since the power has already been turned on again, the process returns to step M5 according to the arrow of N.

If the temperature change ΔT _i is positive in step M7, the process proceeds to step M11 according to the arrow of N. In Step M11, it is determined whether or not power is on. If the power is turned on, it means that the power P2 has been turned on in step M10. In that case, follow step Y12 to step M12.
Proceed to.

In step M12, the detected temperature T _i is compared temperature (T ₀ - [delta
T ₃₎ to determine higher or not than. If the temperature Ti is higher than the comparison temperature (T ₀ −ΔT ₃ ), it is determined that sufficient heating has been performed to reach the target temperature T ₀ , the process proceeds to step M13 according to the arrow Y, and power is cut off. Then step M
Return to 5.

If power is not supplied in step M11,
Since the power is cut off but the temperature rise is continuing, the flow returns to step M5 according to the arrow of N. If the detected temperature Ti is not higher than the comparison temperature (T ₀ −ΔT ₃ ) in step M12, it is necessary to continue the heat generation to reach the target temperature T _0. M5
Return to

In the control shown in FIG. 9, the comparison temperature (T ₀ −ΔT ₁ ) in the initial heating and the comparison temperature (T ₀ −Δ
T ₃ ) can be set separately. Further, the driving power P1 for initial heating and the driving power P2 for reheating can be set separately. Therefore, finer control than the control shown in FIG. 8 is possible.

10A and 10B are flowcharts illustrating another example of the synthesis temperature control. This process is repeatedly performed at a fixed timing. In this control, three types of temperatures lower than the target temperature are used as comparison temperatures, and two types of driving power are used. Also, the heat history shows whether the current power is on or off,
If the power is off, the determination is made based on whether the previous energization was performed with high power or low power.

As the comparison temperature, for example, temperatures lower by 0.5 ° C., 5 ° C., and 8 ° C. respectively than the target temperature are used. When the current synthesis temperature is lower than the target temperature by 8 ° C. or more, heating is performed with large power.

In FIG. 10A, when the process starts, step Q1
, The synthesis temperature T is detected. Next, in step Q2, it is determined whether or not power is currently being supplied. If power is being supplied, the heater is generating heat and Y
According to the arrow, the process proceeds to the process after the QB terminal shown in FIG. 10B.

At the time of startup, power has not yet been supplied, and the determination in step Q2 is negative. Therefore, the process proceeds to step Q10 according to the arrow of N.

In step Q10, the subsequent flow is branched by the flag PR indicating the state of the previous power supply. At the time of activation, the flag PR is “none”. If the previous energization is high power, the flag PR is basically "high",
If the power is low, the flag PR is “low”.

If the flag PR is "None" at startup, step Q11
The process proceeds, the detected synthesis temperature T is to determine higher or not than the higher comparison temperature T _H. Typically, synthesis temperature T is a temperature sufficiently lower than the high comparison temperature T _H, the process proceeds to step Q12 according to the arrow of N.

In step Q12, it is determined whether or not the combined temperature T is higher than the lower comparison temperature _TL . Synthetic temperature T is low comparison temperature T _L
If not higher, go to step Q13 and
Supply _H to heat the bed at a fast heating rate. High heat generated by high power can raise the bed temperature in a short time, but is not suitable for high-precision temperature control. In the vicinity of the target temperature, the small heat generated by the small electric power enables more accurate control.

In summer or the like, the combined temperature T may be higher than the low comparison temperature _TL . In this case, step Q1
The judgment of 2 is yes, go to step Q15,
And supplies the P _L. In this case, the bed heats up at a relatively slow rate. In the case of supplying a high power P _H and low power P _L is a flag PR are "high", set to "low".

Note that, in step Q11, when synthesis temperature T is higher already than the high comparison temperature T _H is not necessary to heat the bed, the flow proceeds to step Q14 follows an arrow Y, the flag P
Set R to low.

Or at the time of startup, normally the above processing high power P _H is supplied to the heater by the step Q13, step Q15
This supplies low power to the heater. Thereafter, when the process returns, in the next step Q2, since power is supplied, step Q50 in FIG.
Proceed to.

In step Q50, the power being supplied to determine whether the high power P _H. If the power is high, the process proceeds to step Q51 according to the arrow Y.

In step Q51, it is determined whether or not the flag RAP is “1”. The normal RAP is “0”, and the process proceeds to step Q52 according to the arrow of N.

In step Q52, it is determined whether or not the combined temperature T is higher than the intermediate comparison temperature T _M. When the combined temperature T becomes higher than the intermediate comparison temperature T _M due to heating by the heater, the process proceeds to step Q53 according to the arrow Y, and the supplied power is turned off. Thereafter, the process returns. If the combined temperature T is not higher than the intermediate comparison temperature T _M , step Q53 is bypassed and power supply is continued.

Thus, when a high power P _H is energized at startup,
Synthesis temperature T is energized to over intermediate comparison temperature T _M is continued, when exceeding the intermediate comparison temperature T _M, energization is terminated. Even after the power is turned off, the bed keeps heating due to the residual heat.

When the power is cut off in step Q53, the next step Q2
Is negative, and the process proceeds to step Q10 according to the arrow of N.

As described above, when the previous energization is high power, the flag PR is “high”, and the process proceeds to step Q21.

At step Q21, it is determined whether synthesis temperature T is higher than the high comparison temperature T _H. Since the supply of high power is stopped at the intermediate comparison temperature T _M , the high power supply does not normally reach the high comparison temperature T _H immediately.

If the synthesis temperature T is not higher than the high comparison temperature T _H is
The process proceeds to step Q22 according to the arrow N, and it is determined whether or not the combined temperature T is higher than the intermediate comparison temperature T _M.

Since the high power has been supplied until the temperature exceeds the intermediate temperature T _M , the determination in step Q22 is normally YES, and the process proceeds to step Q23 according to the arrow Y.

In step Q23, the off timer that counts the length of the power supply stop period after the high power cutoff is incremented. Subsequently, in Q24, it is determined whether or not the count of the off timer has exceeded the count set as the standby time.

Without reaching the high comparison temperature T _H, when the elapsed wait time, the process proceeds to step Q25, starts supplying low power P _L. Thereafter, the process returns. Until the count of the off timer reaches the standby time, the process of step Q24 is NO, and step Q25 is bypassed according to the arrow of N.

That is, after the supply of high power is stopped, if the high comparison temperature _TH is not reached during a certain standby period (for example, three minutes), power is supplied again. Even after the waiting period, if the synthesis temperature than the intermediate comparison temperature T _M is high, low power P _L is supplied.

By the time the standby time elapses, the combined temperature T becomes the intermediate comparison temperature.
If it is equal to or lower than T _M , the determination in step Q22 is NO. This means, for example, that the heat consumption is larger than the residual heat. In this case, the process proceeds to step Q26 according to the arrow of N, for supplying a high power P _H.
In this case, the same control as described above is repeated.

Also, when the synthesis temperature T within the waiting time becomes higher than the high comparison temperature T _H, the process proceeds from step Q21 to step Q27 follows an arrow Y. Since the temperature has been sufficiently increased, the flag PR is changed to “low”.

After initial heating, the supply of low power P _L begins at step Q25, the determination in step Q50 the following figure 10B becomes no, the flow proceeds to step Q61 according to the arrow of N.

Until synthesis temperature T reaches the high comparison temperature T _H, the process proceeds to step Q63 according to the arrow of N, synthesis temperature T is low compared temperature T
_Judge whether it is higher than _L or not. If the combined temperature T is higher than the low comparison temperature _TL , the process proceeds to step Q64, and the on-timer for counting the length of the low power supply period is incremented.

Subsequently, the process proceeds to step Q65, where it is determined whether or not the time of the on-timer has passed, for example, 10 minutes. The process is returned until 10 minutes have elapsed. If the synthesis temperature T is higher than the high comparison temperature T _H in 10 minutes, step Q61
Then, the process proceeds to step Q62 according to the arrow of Y to terminate the power supply.

When after 10 minutes does not exceed T _H, the process proceeds from step Q65 to step Q66 follows an arrow Y, to supply high power P _H, sets the flag RAP to "1". Then, the process returns.

In this case, the answer is yes in the next step Q50, and the answer is yes in step Q51. Synthesis temperature T in step Q56 is determined whether exceeds the high comparison temperature T _H, when it exceeds returned to "0" flag RAP with interrupts power proceeds to step Q57.

That is, when the high comparison temperature _TH is not reached even after the low power is supplied for 10 minutes, it is determined that rapid heating is necessary, and the high power is supplied, but the flag RAP is set to distinguish this state. .

If the synthesis temperature T is not higher than the low comparison temperature _TL before 10 minutes have elapsed, it is determined that the synthesis temperature has dropped too much. Go from step Q63 to step Q67 to get high power
And supplies the P _H.

Although the low power supply period is set to 10 minutes, this time may be changed according to the power, operating room conditions, and the like.

If the high comparison temperature _TH is exceeded by low power supply,
Proceeding from step Q61 to step Q62, power supply was terminated. Thereafter, the determination in step Q10 becomes "low", and the process proceeds to step Q31.

In step Q31, the synthesis temperature T is to determine higher or not than the high comparison temperature T _H. If the synthesis temperature T is higher than the high comparison temperature T _H, the process returns follows an arrow Y.

If the synthesis temperature is not higher than the high comparison temperature T _H is, N
The process proceeds to step Q32 according to the arrow of (3) to determine whether the combined temperature T is higher than the low comparison temperature _TL . If the synthesis temperature T is higher than the low comparative temperature T _L, the process proceeds to step Q33 follows an arrow Y, and supplies the low power P _L. That is, the synthesis temperature T exceeds the high comparison temperature T _H low power P _L is turned off, T _H
If cracking a low power P _L is turned on.

In Step Q32, if the synthesis temperature T is not higher than the low comparative temperature T _L is not normally occur, if it occurs if the process proceeds to step Q34, supplying a high power P _H. Steps Q34 and Q67 are for performing rapid heating with high power when the synthesis temperature drops rapidly for a special reason that does not normally occur.

In the control flow shown in FIGS. 10A and 10B, the temperature change Δ
The prediction control is performed based on the past power supply without detecting T. The intermediate comparison temperature T _M is used only for high power interruption and subsequent monitoring, and is lower than the high comparison temperature T _H , but is not necessarily higher than the low comparison temperature T _L. Two types of comparison temperatures may be used, and T _M and T _L may be the same.

In the above control, when two types of power are used, for example, these powers can be formed by full-wave and half-wave AC power. In the case of DC drive, a full-wave and a half-wave may be extracted and rectified by a triac. Power is provided with a simple configuration.

The control shown in FIGS. 8, 9, 10A, and 10B is only a control portion based on the combined temperature T. When an abnormal signal from the temperature detection sensor 10 of the sheet heater or the electric knife is detected,
The control is interrupted regardless of this control flow.

FIG. 11A shows an air mat with a heating function according to another embodiment of the present invention. A plurality of air cells 1 are arranged in parallel, and adjacent side wall portions are bonded to each other by welding or the like. On the lower side of the air cell 1, a support sheet 33 enclosing a planar heater is disposed.

Wrapped in air cell and support sheet 33, bag 6
Is arranged. A compressed air and power connector 35 is arranged beside the parallel arrangement of the air cells 1.

FIG. 11B shows a planar shape of the air mat shown in FIG. 11A. The planar heater is formed by being divided into two portions 33a and 33b. The planar heater 33b corresponds to the upper body of the patient, and the planar heaters 33a and 33b correspond to the whole body of the patient. Temperature fuses 13a, 13b are arranged on these planar heaters 33a, 33b. In addition, on the upper surface of the air mat, the combined temperature detection sensors 9a, 9b correspond to the respective planar heaters 33a, 33b.
Is arranged. Note that the thermistor 10 for detecting the temperature of the heater is provided only in the planar heater 33b for the upper body. In addition, a connection pipe 37 for transmitting compressed air, a drive current, and a detection signal is connected to the socket 35.

The connecting pipe is connected to the control device shown in FIGS.
In FIG. 12A, a control panel 41 is arranged on the upper front part of the control device 40, and an air pump P is arranged below it.

As shown in FIG.12B, in the control panel 41, a power switch 42, an air supply switch 43, an upper body heating switch 44, a whole body heating switch 45, a set temperature lowering switch 46, and a set temperature increasing switch 47 are arranged. I have. The combined temperature is displayed on the display 48, and the set temperature is displayed on the display 49. Further, lamps 51 and 5 are provided above these indicators 48 and 49.
2 and 53 are arranged to display a heated state, a warmed state, and an abnormal state, respectively.

As shown in FIG. 12, a socket 55 is arranged on the control device surface, and is connected to the communication pipe 37 shown in FIG. 11B. The control device is housed in a metal housing. The power supply for the heater and the control circuit is constituted by an electrically shielded transformer or the like, and is housed in a metal housing. The electric shield prevents adverse effects on the electrocardiogram and the like.

FIG. 13 is a graph showing the measurement results of the operating table air mat described above. The horizontal axis indicates the passage of time t, and the vertical axis indicates the synthesis temperature T. The set temperature is 38 ° C.

The curve t1 is obtained by following the control of FIGS. 10A and 10B, T _M = T _L = T ₀ −5
° C, T _H = T ₀ −0.5 ° C., and indicates the synthesis temperature detected by the synthesis temperature detection sensor. Synthetic temperature by initial heating
t1 once rises to 40.7 ° C., then falls, and is then maintained at around the set temperature of 38 ° C.

In the illustrated state, excluding the initial overshoot, the synthesis temperature is kept in the range of 37.2 ° C. to 38.6 ° C.

Curve t2 shows the change in the patient's body temperature. The patient's body temperature
Although slightly lower after the start of the operation, it maintains an almost constant body temperature and reaches 36.1 ° C when awake after the end of the operation.
The room temperature t ₃ in the operating room is shown on the lower side for comparison. room temperature
t ₃ is lowered at the start of the operation, is maintained at approximately 23 ° C. during the operation, and drops to 22.5 ° C. after the operation. That is, even if the room temperature is cooled to around 23 ° C, the patient's body temperature can be kept at around 36 ° C.

Note that this measurement is performed when two types of comparison temperatures are set. If three kinds of comparison temperatures are set as in the control shown in FIGS. 10A and 10B, finer control becomes possible. For example, it is possible to further reduce the initial overshoot.

Further, the planar heater driving current is turned on / off or increased / reduced.
Although the case of changing to small / off has been described, the heater drive current may not be turned off during use of the air mat, and the current off state may be replaced with an idle state in which a constant small current flows. The current value may be set to multiple levels. Further, the current value may be controlled continuously.

Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. For example, various changes,
It will be obvious to those skilled in the art in the claims that improvements, combinations, and the like can be made.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-222915 (JP, A) JP-A-58-116216 (JP, A) JP-A-6-13158 (JP, A) JP-A-6-158 343664 (JP, A) Japanese Utility Model Application Showa 57-57836 (JP, U) Japanese Utility Model Application Showa 60-129918 (JP, U) Japanese Translation of PCT International Publication No. 3-502410 (JP, A) US Patent 4,175,297 (US, A) US Patent 4,149,066 (US, a) United States Patent 5267365 (US, a) United States Patent 4652726 (US, a) United States Patent 2998817 (US, a) United States Patent 4814583 (US, a) (58 ) investigated the field (Int.Cl. ^7, (DB name) A61G 13/00 A61G 7/04 A47C 27/08

Claims (21)

(57) [Claims] 1. A plurality of groups of air cells arranged on a longitudinally extending bed surface, each air cell being formed of a deformable bag-like sheet, having an air-permeable opening,
A plurality of groups of air cells that can cooperate to form a resilient support surface on which the patient undergoing surgery is placed, and disposed below the plurality of groups of air cells, A sheet heater having a sheet-like shape having an area including a portion; a deformable bag enclosing the sheet heater and the plurality of groups of air cells; and a temperature T which is mounted on the upper surface of the bag and detected. A temperature sensor for generating a temperature signal representative of: a group of air cells that do not supply air; and a selective air supply means for selectively supplying air to the plurality of groups of air cells. A control means for receiving a temperature signal and controlling power supply to the planar heater based on the measured temperature. 2. The operating table air mat according to claim 1, wherein said control means controls the power supply based on a value of the temperature T represented by said temperature signal and a history of changes in the temperature T up to that value. apparatus. 3. The control means can set a target temperature T _0, and when the temperature T rises, supply power when the temperature exceeds a temperature (T ₀ −ΔT ₁ ) lower than the target temperature T ₀ by a predetermined temperature ΔT _1. 3. The air mat apparatus for an operating table according to claim 2, wherein the air mat is reduced. 4. The control means can set a target temperature T _0, and when the temperature T is falling, supply power when the temperature falls below a temperature (T ₀ + ΔT ₂ ) higher than the target temperature T ₀ by a predetermined temperature ΔT _2. 3. The air mat device for an operating table according to claim 2, wherein the air mat device is increased. 5. The operating table air mat apparatus according to claim 2, wherein said control means is capable of supplying a large power and a small power smaller than said power, and varying control after power supply according to the power. 6. The control means according to claim 1, wherein said control means controls a time after a large power supply is stopped
6. The air mat apparatus for an operating table according to claim 5, wherein the control is changed based on a time during which the small electric power is supplied. 7. The operating table air mat apparatus according to claim 1, wherein each of said air cells has a diameter of about 4 to 8 cm when air is filled therein. 8. Each of the air cells is long in a direction substantially perpendicular to the length direction, and the diameter of an air cell disposed at a central portion in the length direction of the bed surface is in the length direction of the bed surface. 8. The air mat apparatus for an operating table according to claim 7, wherein the diameter is smaller than the diameter of the air cells arranged at both ends. 9. An air mat apparatus for an operating table according to claim 1, wherein said bag includes a sheet formed of polyester and a metal layer formed on an inner surface of the sheet. 10. The apparatus according to claim 1, further comprising a terminal for receiving a signal indicating the use of the electric knife or the laser knife, wherein the control means stops supplying power to the planar heater while the electric knife or the laser knife is being used. 2. An air mat device for an operating table according to claim 1. 11. A sheet heater according to claim 1, wherein said sheet heater has a support sheet and a resistance heater layer formed on the surface thereof.
Item 11. An air mat device for an operating table according to any one of Items 10. 12. The air mat apparatus for an operating table according to claim 11, wherein said resistance heater layer contains carbon. 13. A method of operating an operating table air mat capable of periodically changing a patient's weight supporting surface, comprising: activating a heater provided on a lower surface of an air layer of the air mat.
The temperature T _{i is determined} by the heat generation step of generating heat and the sensor provided on the upper surface of the air layer of the air mat.
Measuring a, the measured temperature T _i target temperature T ₀ than [Delta] T ₁ lower compared temperature (T ₀ -.DELTA.T ₁₎ and comparing with the measured temperature T _i is compared temperature (T ₀ -.DELTA.T ₁₎ Lowering the drive current of the heater when the air conditioner reaches the operating temperature. 14. Further, the measured temperature T _i and the previous measured temperature T
a step of obtaining a difference _{ΔT i = T i -T i-} 1 of the _i-1, the measured temperature on the basis of the T _i and the difference [Delta] T _i, surgery claims Paragraph 13, further comprising a control step of controlling the heater How to operate the table air mat. 15. The control step according to claim 14, wherein the control step includes a heat keeping step of increasing the drive current of the heater when ΔT _i becomes zero or negative and the measured temperature T _i becomes lower than T ₀ + ΔT _2. The operating method of the operating table air mat described. 16. The control method according to claim 1, wherein ΔT _i is positive and the measured temperature T _i
16. The operating method for an operating table air mat according to claim 15, further comprising a temperature rise prevention step of reducing a drive current of the heater when the temperature is higher than T ₀ + ΔT ₃ . 17. The operating method for an operating table air mat according to claim 15, wherein the heat generation step and the heat retaining step in the control step are performed at different current values. 18. The operating method of an operating table air mat according to claim 13, further comprising a control step of performing current supply control based on the measured temperature T _i and a history of current supply. 19. The operating table for an operating table according to claim 18, wherein the control step performs different control depending on whether the measured temperature T _i once exceeds another comparison temperature higher than the comparison temperature or not. How to operate the air mat. 20. The operating method of an operating table air mat according to claim 19, wherein the driving current lowering step is a step of cutting off a current, and further includes a step of measuring a current cutting time. 21. The operating table air according to claim 20, wherein said control step supplies a drive current lower than said drive current when a set temperature rise cannot be obtained even when the current disconnection time reaches a set value. How to drive the mat.