Medical device and method for operating a medical device

Abstract

Medical device (1) with means (3) for switching the device (1) on and off, where switching on activates the device and puts it into an operating state, and switching off deactivates the device and ends the operating state, wherein the device (1) performs at least one safety-related function in the operating state using at least one operating parameter with a defined setpoint, characterized by that the device (1) performs a first self-diagnosis after being switched on and before reaching the operating state and a second self-diagnosis after being switched off and before the end of the operating state, in each case checking the same operating parameter of the at least one operating parameter of the device (1) for deviations from the setpoint value, wherein a deviation of the operating parameter from the specified setpoint within a value range is stored by the device (1) as a tolerance, and a deviation outside the value range is stored by the device (1) as an error, where the first self-diagnosis is based on a first range of values ​​and the second self-diagnosis is based on a second range of values, the second range of values ​​being smaller than the first.

Description

[0001] The invention relates to a medical device with means for switching the device on and off, in order to activate the device and put it into an operating state, and to deactivate it and end an operating state. Upon switching on, the device performs a self-diagnosis.

[0002] Medical devices fulfill a wide range of functions in medicine. They serve, among other things, to provide liquids and gases, light, electricity, or heat; to supply connected medical instruments; and to control and regulate instruments, other devices, and components. Well-known medical devices include suction and irrigation pumps, light sources, generators for high-frequency surgery, as well as camera control units, insufflators, and devices for navigated surgery. What they all have in common is that they provide medical users with various functions necessary for the successful treatment of patients. Medical devices are often interconnected with instruments, other components such as input devices and monitors, or with each other, exchanging signals, power, or other utilities.The function of the devices has a direct impact on the intended application and the patient, and therefore represents a safety-relevant aspect. Medical devices are thus frequently equipped with redundant sensors and other means that enable safe operation and detect malfunctions. All safety-relevant functions of a device are continuously monitored during operation. It is standard practice that a detected malfunction or an operating parameter measured outside of specified target values ​​is automatically communicated to the user, and if necessary, further operation of the device is prevented. A balance must be struck between the greatest possible patient safety and the requirement for a smooth treatment process, such as surgery.The continuous availability of a medical device's function may be essential for a medical procedure, making any interruption of operation unacceptable. Therefore, any malfunction of a device should be detected promptly and with a high degree of certainty, and simultaneously communicated to the user at the appropriate time.

[0003] For example, US Patent 2008 / 0147136A1 discloses the practice of having a medical device perform regular self-diagnoses while deactivated, i.e., when it is not in operation. These self-diagnoses can be performed, for instance, after a certain period of time. This ensures that a device functions correctly when it is needed and that any deviations are detected before use, allowing for adjustments or repairs.

[0004] From DE102011118265A1 it is known to perform a second self-diagnosis when a device is shut down into a sleep mode, in which fewer functions are checked than in the first self-diagnosis.

[0005] From EP0671687A2 it is known to have a device perform a self-test independently outside of a normal operating phase and, if necessary, to save an error message.

[0006] US2015 / 0261637A1 describes a self-diagnostic unit for microcomputers that divides self-diagnosis into functional blocks that are performed at different times.

[0007] DE10146894C1 discloses an operating method for medical devices in which the device's condition is monitored during operation and, if necessary, a self-test is performed to avoid endangering patients during operation.

[0008] The disadvantage of this method is that the device must be constantly connected to a power source. This well-known type of self-diagnosis is particularly suitable for mobile, battery-powered devices that are used only rarely, such as defibrillators.

[0009] The aforementioned prior art also describes a known solution in which a self-diagnosis is performed during the power-on process. However, a negative result, such as a malfunction or operating parameters measured outside of predefined values, leads to potential delays or even interruptions after power-on, which can disrupt patient treatment. It is therefore an object of the present invention to provide a medical device and a method for operating a medical device that reliably detects malfunctions and deviations in the device's operating parameters and also increases the probability that the device is ready for operation at the time of use. The aforementioned disadvantages are to be avoided.

[0010] According to the invention, the problem is solved by a medical device according to claim 1 and a method according to claim 12.

[0011] A medical device includes means for switching the device on and off, wherein switching on activates the device and puts it into an operating state, and switching off deactivates the device and ends the operating state. In the operating state, the device performs at least one safety-related function, using at least one operating parameter with a defined setpoint for this purpose. After switching on and before reaching the operating state, the device performs an initial self-diagnosis, and after switching off and before ending the operating state, it performs a second self-diagnosis, in each case checking the same operating parameter of the device for deviations from the setpoint.

[0012] As previously described, a medical device provides various functions for patients and users. The device can be a single unit containing components for fulfilling its function, or it can be distributed across multiple components. It can include input devices, displays, and lines for power, signals, or fluids (liquids or gases). The device may have a control system. Devices of the same or different types can be interconnected, exchange signals, be controlled jointly by one of the devices, or be controlled centrally by a control unit. Input devices and displays can be attached directly to the device housing or positioned separately and connected via cables. Examples of input devices include keyboards, control buttons, touchscreens, foot switches, or microphones for voice control.

[0013] Medical devices include, for example, suction and / or irrigation pumps designed to perform a rinsing or suction function. They provide the user and patient with fluid for rinsing the surgical site or suction blood, fluid, or smoke gas from it. For this purpose, a pump is connected via fluid lines directly to the patient or to a channel of a medical instrument, such as an endoscope or instrument for high-frequency surgery, which is used on the patient.

[0014] The device has switches or other input devices for turning it on and off. This can be done via switches directly on the device, a touchscreen, voice input into a microphone, a switch on a central control unit, or another separate input device. Multiple devices can be activated or deactivated simultaneously. The switches or input devices can also be integrated into the medical instrument and control it. A switch can be a pressure switch, lever, or any other component known to a person skilled in the art for switching. The device can also be activated at a specific time or depending on the operating state of another device. For example, a smoke extraction pump or its associated pinch valve can be activated and deactivated depending on the activity of an RF generator or RF instrument.

[0015] In the following, switching on and off refer to triggering the on and off process, i.e., initiating an activation or deactivation in which the device is brought into an operating state or this operating state is ended. This can also include starting up or shutting down a device controlled by software. Switching on or off is a request to the device or its control system to activate or end the operating state. Switching on and off can also involve connecting the device's power supply to a power source. Alternatively, the device may be in an electrical standby state, from which it is awakened by switching on or returned to this state by switching off.

[0016] A device is in an operational state when it is ready to perform the function provided by the device. This can happen automatically or upon further prompting or input from the user.

[0017] In this context, a safety-relevant function is understood to be a function that the device performs or provides and that can affect the safety of a patient or operator. In medical devices, virtually all functions will be safety-relevant, although some functions may be more critical than others. For example, providing power for an electrosurgical application is a highly safety-relevant function, as the current poses a risk to both patient and operator. This function is therefore subject to strict limitations and specifications through setpoints and design features within the device to eliminate any risk to patients and operators.

[0018] Similarly, the provision of insufflation gas by a device such as an insufflator represents a safety-relevant function, since the gas is supplied directly to the patient and overpressure can harm the patient.

[0019] To control and monitor the device's function, at least one operating parameter is required, which defines and enables the device's operation. This could be, for example, a voltage, a current, a pressure, a temperature, a fluid flow rate such as CO2 gas or water, a luminous flux, or a supplied amount of energy. A voltage can be the supply voltage to the device or a component of the device, or it can be a voltage between components within the device.

[0020] The present invention relates in particular to mains-powered devices, i.e., devices that are connected to the mains power supply, for example via a power adapter, and are operated solely via mains power. In particular, they do not have a mobile energy source such as a battery.

[0021] An operating parameter is assigned a single setpoint or a range of setpoints that represent the preferred value for the device's operation and functionality. The setpoint may be programmed into the device, parts of the device, or device software, or it may be set by the user via input devices. The setpoint may depend on the medical application, the materials and components used, or even environmental conditions such as ambient temperature. The device may also include a control system that adjusts the setpoint based on other operating parameters or the intended application. The setpoint for the operating parameter may differ between the first and second self-diagnostics.

[0022] To ensure the safe operation of the device, it performs an initial self-diagnosis after being switched on and before reaching its actual operating state. This means that the device uses sensors or other components, such as an electrical circuit, to measure or record the actual value of the operating parameter(s) and compares it to the target value. Any deviation of the measured value from the target value should be detected. All operating parameters or only individual parameters can be checked.

[0023] Similarly, after being switched off and before the actual end of the operating state, the device performs a second self-diagnosis. This can be carried out in the same way as the first self-diagnosis. In both self-diagnostics, a specific operating parameter is measured, and the recorded value is compared with the target value. A deviation occurs if the measured value of the operating parameter does not correspond to the target value or the range of target values. For the purpose of controlling the device, triggering and carrying out the self-diagnosis, and / or evaluating and comparing the measured values, the device can have a control system of a known type. This includes, for example, at least one microprocessor and a memory. Alternatively, the evaluation takes place in another device connected to the device via signal lines.

[0024] A deviation from the target value of an operating parameter can have various causes. For example, advanced age and wear of the device's components can lead to deviations. Stress on electronic and other components due to high temperatures, contamination of mechanical parts, or improper handling of the device by operators can also cause desired values ​​for voltage, power output, airflow, or similar parameters to no longer correspond to the target values. In this context, a deviation from a target value is initially only a quantitatively recorded event. Depending on its extent and assessment, it can then be safety-relevant or even indicate a malfunction of the device. However, it can also be negligible and, for example, occur due to the device heating up during operation, which is then detected during the second self-diagnosis.

[0025] Similarly, deviations can occur due to the influence of high temperature or other environmental conditions on the measuring sensors. This means that the detected deviation of an operating parameter may not actually be attributable to the operating state of the device, but rather to the sensor itself, which may be delivering incorrect or inaccurate readings due to less-than-ideal environmental conditions. The second self-diagnostic function can also detect and account for this, especially if the sensor's behavior is known to vary depending on ambient temperature or other environmental conditions.

[0026] Performing two self-diagnostics at different times, one after switching on and one after switching off, increases the reliability, quality, and reliability of the measurement. This is because multiple measurements are taken and different phases of the device's operation are considered. A device that has warmed up during operation behaves differently than one that has just been switched on.

[0027] Each time the device is switched on, it triggers the first self-diagnosis, and each time it is switched off, it triggers the second self-diagnosis. The self-diagnostics are therefore performed by the device during every power-on and power-off process, which further increases safety.

[0028] Furthermore, two self-diagnostic functions offer various possibilities for comparing and processing the values ​​and deviations, and for drawing conclusions about the actual condition of the device. For this purpose, the technician will install software on the device that processes and evaluates the operating parameter values ​​as required.

[0029] If a deviation or error is detected after the device is switched off and during the second self-diagnosis, this can be addressed before the device is restarted by recalibrating or servicing it. Unexpected deviations occurring only after the device is switched on are avoided as much as possible, so that the device can be brought into operating mode and used as planned. This is particularly important in operating rooms to prevent disruptions to schedules or the need to cancel operations due to the lack of an alternative device.

[0030] For example, during the first and second self-diagnostics, the device can check whether an internal supply or reference voltage deviates from the target value and whether safe operation of the device is still possible. Alternatively, the flow of an internal cooling airflow could be measured to detect deviations that would result in undesirable heating of the device. The amount of energy generated in high-frequency current, ultrasound, or laser applications can also be measured and checked for deviations from the target value.

[0031] In one embodiment of the invention, a detected deviation of the operating parameter from the specified target value within a value range is stored by the device as tolerance and a deviation outside the value range is stored by the device as an error, wherein the first self-diagnosis is based on a first value range and the second self-diagnosis is based on a second value range and the second value range is smaller than the first.

[0032] Here, the data can be stored in memory within the device itself or in the memory of a connected component or controller. As previously described, software can be available on the device that evaluates the measured values ​​of the operating parameter and determines whether a deviation from the target value is still within or already outside the value range. The value range is a range of possible values ​​that the operating parameter can assume, encompassing the target value, and which is considered tolerable. The result of this evaluation is then stored as an error if the deviation is outside the value range, or as a tolerance if it is within the value range. This can be a value representing an error and a value representing a tolerance, or a more detailed result corresponding to an error or a tolerance as defined here.For further analysis, software can access the memory and read the value.

[0033] Furthermore, the first self-diagnosis after power-up now assumes a larger range of acceptable deviations than the second self-diagnosis after power-off. In the second self-diagnosis, a narrower or smaller range of permissible deviations of the operating parameter is used around the target value, thus applying a stricter standard to the permissible deviation than in the first self-diagnosis. Generally, the range of values ​​can also correspond to a single target value. The second range of values ​​can be at least 25% smaller than the first, and in particular at least 50% smaller. The size of the range refers to the difference between a maximum and a minimum value within the respective range. The ranges encompass the target value; however, the smaller second range does not necessarily have to be completely contained within the larger first range.

[0034] This advantageously allows the device to operate even with larger deviations in the values ​​after the initial diagnosis. Only when the device is switched off is a smaller value range permitted, meaning that less serious deviations are not recorded as errors. Conversely, even minor deviations now result in an error. After the device has been operated, the user can react and correct the error before putting it back into operation, ensuring the device is then available in perfect working order.

[0035] The smaller, second value range for the second self-diagnosis also has the advantage that deviations in the measured values ​​from the target value of the operating parameter caused by changes in environmental conditions during the device's operation can be taken into account and compensated for. For example, if the device has heated up during operation and this heating affects the measuring electronics of the sensors, it can happen that values ​​of the operating parameter, such as voltage or pressure, no longer correspond to the actual values. The measured values ​​deviate or are somewhat erroneous, so that for safety reasons it makes sense to allow a smaller tolerance, i.e., to use a smaller value range for the second self-diagnosis, so that completely impermissible values ​​of the operating parameter are always registered as errors. This also occurs if the sensors no longer measure reliably or display values ​​that deviate from reality.The expected deviations are taken into account by the smaller value range. This is particularly possible when the behavior of the sensors under changing operating conditions is known.

[0036] The effects of a detected error during the first and / or second self-diagnosis can vary depending on the operating parameter, for example, determined by software on the device, as will be described in more detail below.

[0037] If a fault is stored during self-diagnosis, an audible or visual warning can be generated. The device itself can generate the warning. Alternatively, the stored fault can be communicated to another device or connected component, which can then generate the warning. The visual warning can be a light such as an activated LED, a flashing light, or a display such as text. An audible warning can be a tone or voice output generated by the device or the connected component. The device may have a built-in speaker for this purpose.

[0038] If the measured deviation of the operating parameter from the specified range is so large that an error is recorded, the user is alerted by a generated warning. Depending on the severity of the deviation or malfunction, this can occur immediately, when the device is switched off, or after it is switched on again. The warning allows the user to react to the deviation or error and, if necessary, take corrective action. In this way, a malfunctioning device can prevent it from affecting the user or the patient. For example, this can prevent overheating or overvoltage.

[0039] The warning can be generated if the first self-diagnosis detects a fault, if the second diagnosis detects a fault, or only if both diagnoses detect a fault for the relevant operating parameter. This can also depend on the relevance of the parameter and the affected components and functions to the application. When selecting these options, the person skilled in the art will consider that, according to the task to be solved, the safe operation of the device must be ensured on the one hand, and on the other hand, it must be possible to react to faults in the operation of the device at the appropriate time.

[0040] In general, both the first and second self-diagnostics can involve multiple measurements of an operating parameter, or multiple sensors can determine the same parameter value.

[0041] For devices and additional components such as foot switches, monitors, and the like that are interconnected via signal lines, wireless connections, BUS systems, or the like, the first and second self-diagnostics can also include operating parameters of these additional devices and components.

[0042] In one embodiment of the invention, the warning is generated after a further power-on and before another initial self-diagnosis of the device. If an error was stored during the first or second diagnosis in the previous operation of the device, this error can also be communicated to the user as a warning after a further power-on.

[0043] The warning can advantageously also include instructions for the user. That is, it can give the user guidance on how to deal with the displayed error. This can be done via an audio message, as text on a display, or through a visual or audible signal with a meaning defined, for example, in a user manual. The instructions can guide the user on how to rectify the error.

[0044] A stored error detected during the first and / or second self-diagnosis may prevent the device from being switched back on. In an emergency, this can prevent the faulty device from being used and endangering the patient or user.

[0045] In a further implementation, and possibly depending on the relevant operating parameter, the warning is only generated if an error is stored during the first and second self-diagnostics. This ensures that an error actually exists and that the cause has not already disappeared during operation.

[0046] Alternatively or additionally, a warning can be generated if a tolerance is stored during the first self-diagnosis and an error is recorded during the second. An error recorded after shutdown and during the second self-diagnosis allows the user to react to the error without interrupting the treatment process. If a smaller range of values ​​for the deviation of the operating parameter was used as the basis for the second self-diagnosis, it will often occur that a value is still within the larger range after startup, but even if the value does not change during operation, it falls outside the narrower range of the second diagnosis after shutdown and generates an error. At this point, the user can again react to the error.

[0047] To ensure that the user takes note of an error, the device may be configured so that after an error is stored, during the first or second or both self-diagnostics, it does not immediately terminate its operating state even after being switched off. Specifically, a warning is generated and displayed. The operating state is then only terminated once the error has been addressed appropriately.

[0048] It is an aspect of the present invention that the device performs a self-diagnosis only after being switched on and after being switched off, but not in a standby state after the end of operation.

[0049] A method according to the invention for operating a medical device comprises the steps - Switching on the device - Performing an initial self-diagnosis, in which at least one operating parameter is checked for deviation from a target value of the operating parameter, - Activating the device and putting the device into an operating state - Switching off the device - Performing a second self-diagnosis, in which at least the first operating parameter is checked for deviation from a target value of the operating parameter, - Ending the operating state.

[0050] In one embodiment of the method, a deviation of the operating parameter from the specified target value within a value range is stored by the device as tolerance and a deviation outside the value range as error, wherein the first self-diagnosis is based on a first value range and the second self-diagnosis is based on a second value range, the second value range being smaller than the first.

[0051] The procedure may include, after the step of performing the second self-diagnosis, the additional step of generating a visual or audible warning in the event that an error is stored after the second self-diagnosis.

[0052] Furthermore, all other previously described possible aspects of a medical device according to the invention can also be aspects of the device operated by the method described here.

[0053] Further aspects of the invention will become apparent from the following description of the preferred embodiments and the accompanying drawings. These show: Fig. 1 an embodiment of a medical device according to the invention Fig. 2 a circuit diagram of a medical device according to the invention Fig. 3 a diagram of measured values ​​from the first and second self-diagnosis, as well as the first and second value ranges Fig. 4 a diagram of a method according to the invention

[0054] A in Fig. The medical device 1 shown in Figure 1 has a housing 2 and an on / off switch 3 in the form of a push button, located on the housing 2. A gauge 4, for indicating a set pressure, and a display 5 are located on the front of the housing. A light-emitting diode 6 is located on the top of the housing 2, and a speaker 7 is located on one side of the housing 2. The device 1 is connected via a power cord 8 to a power outlet (not shown), which supplies mains voltage. A signal line 9 connects the device 1 to an input device in the form of a foot switch 12. On the opposite side of the housing 2, a fluid line 10 in the form of a tube is connected to the device 1. The fluid line 10 leads to a trocar 11.In the present embodiment, the device 1 is an insufflator that can supply a patient with an insufflation gas, for example CO2, via the fluid line 10 and the trocar 11. For this purpose, the gas is introduced under pressure into the patient's body by the insufflator 1 via the line 10 and the trocar 11, for example, to expand the abdominal cavity for an endoscopic operation. The trocar 11 is inserted into the patient's abdominal wall for this purpose.

[0055] Fig. Figure 2 shows a schematic circuit diagram of device 1. Device 1, whose housing 2 is indicated by the dashed lines, has a control unit in the form of a microcontroller 21 and two sensors 22a and 22b, which measure and regulate the pressure in line 10 between gas cylinder 20, device 1, and the patient to prevent overpressure in the patient. Overpressure would endanger the patient's safety. Regulation is achieved, for example, via a pressure regulator (not shown) connected to line 10 and also controlled by the microcontroller 21. The target pressure, either specified by device 1 or set by the user, is displayed to the user on display 4. Sensors 22a and 22b, along with other electronic components, are mounted on a circuit board (not shown) inside housing 2. Device 1 heats up during operation, which increases the temperature inside housing 2.The electronic components and sensors 22a, b must be protected from overheating, as otherwise they could malfunction and provide faulty readings. A target temperature Ttarget is specified for device 1 via software running on the microcontroller 21 of device 1. The circuit board therefore also includes a temperature sensor 23, which measures the temperature inside the housing 2. The controller 21 of device 1 also monitors this measured value.

[0056] The user activates device 1 via switch 3, thereby establishing a power supply from a power source 25 to device 1 via the power cord 8. Immediately after being switched on, device 1 performs an initial self-diagnosis. During this process, various operating parameters of device 1 are checked, including the temperature T of the housing interior measured by temperature sensor 23.

[0057] In Fig. Figure 3 shows the result of the temperature measurement. At time t1, the first measurement is performed as part of the initial self-diagnosis, and a value Ta for the internal temperature is determined. This value is above the target temperature Ttarget, but within a first value range shown with dotted lines, defined by a lower limit T1 and an upper limit T2. The controller 21 of device 1 evaluates the measurement result as part of the initial self-diagnosis and compares the first measured value Ta with the predefined first value range. This value range represents the range within which deviations from the target temperature Ttarget are acceptable, as they do not pose an immediate risk to the electronic components. The controller 21 of device 1 stores the measurement result, which is within tolerance, in a memory location 24. Since no error has occurred, device 1 is put into an operating state and is available to the user.The gas supply to the patient can now be triggered by the user via foot switch 12 as needed.

[0058] After completion of the medical procedure, the user switches off device 1 using switch 3. At this time t2, device 1 performs a second self-diagnosis and, among other things, checks the temperature inside housing 2 again. As in Fig. As can be seen in Figure 2, the measured value Tb is now higher than the measured value Ta at the beginning of the intervention. Device 1 has heated up during operation. The second self-diagnosis is based on a second value range for the temperature T, with a minimum temperature T3 and a maximum temperature T4, shown hatched in the diagram. This range is smaller than the first value range; in particular, the maximum temperature T4 is below the maximum temperature T2 of the first value range. The measured temperature Tb inside device 1 is no longer within the second value range, but above it. The controller 21 therefore detects an intolerable deviation of the temperature T from the setpoint temperature Tsetpoint and stores the value as an error in memory 24.

[0059] In Fig.Figure 4 illustrates the process according to the invention by way of example. It begins with the step of switching on the device 41, followed by the first self-diagnosis step 42 of the device 1. Here, two cases can occur: either an error is detected and stored in memory 24 in the next step 43, or no error is present, in which case the device 1 enters the operating state in the next step 44.

[0060] After completion of a medical procedure, device 1 is switched off in the next step 45, followed by the second self-diagnosis 46. Here again, two scenarios are possible: either an error is recorded in the next step 47, or the operating state is terminated in the final step 48.

[0061] In this case, an error was stored during the second self-diagnosis. To inform the user of the error, a tone is generated via the speaker 7 and the LED 6 illuminates as a warning in a further step of the procedure, before step 48. A message appears on the display 5 indicating that the device 1 has overheated. The message also advises the user to ensure that the cooling slots 13 on the housing 2 are not obstructed and not to switch the device 1 on again for a period of 15 minutes to allow it to cool down. The operating state of the device 1 is not terminated immediately after the second self-diagnosis 46 is completed; instead, the device 1, and in particular the fan 14, continue to run for another five minutes to lower the internal housing temperature more quickly and prevent damage to the electronic components.Only then does device 1 finally switch off and the connection to mains power 25 is interrupted.

[0062] In an alternative embodiment, the device 1 is configured as described above and connected to the other components 11, 12, and the gas cylinder 20, but it does not have a temperature sensor to measure the temperature in the housing 2 of the device 1. Instead, during the first self-diagnosis, the pressure P1 applied to line 10 is measured by the pressure sensors 22a and b. If the measured values ​​of the pressure P1 are within a first range around the setpoint pressure Psetpoint, the device 1 is activated and put into operating mode. After the end of the medical procedure, the device 1 is switched off again, and the second self-diagnosis is then performed by the device 1 itself. It is known that the device 1 heats up during operation, and the increased temperature in the device 1 affects the measurement results of the pressure sensors 22a and b.During the second self-diagnosis, the pressure P2 in line 10 is measured using pressure sensors 22a and 22b. When evaluating the measured values, a second, smaller range of values ​​around the target pressure Ptarget is used. This smaller second range is stored in the device control unit 21 and sets a narrower limit for the permissible pressure P2 values ​​that are to be tolerated than the first range. This takes into account that pressure values ​​measured by the heated pressure sensors 22a and 22b may not always correspond to the actual pressure values ​​in line 10 due to thermally induced influences on the electronics. For safety reasons, a stricter standard is applied to the permissible pressure values, and this determines whether a fault or a tolerance exists when the measured values ​​are evaluated in the control unit 21. Depending on the measurement result, the device 1 can then be deactivated or a warning issued, as described previously. Reference symbol list: 1 medical device 2 cases 3 switches 4 Display 5 Display 6 LEDs 7 speakers 8 power cables 9 Signal line 10 Fluid line 11 trocar 12 foot switches 13 cooling slots 14 Fan 20 gas cylinders 21 microcontrollers 22a, b Pressure sensors 23 Temperature sensor 24 storage 25 Power source 41 Switch on 42 first self-diagnosis 43 Saving an error 44 Activating an operating state 45 Switch off 46 second self-diagnosis 47 Saving an error 48 Ending the operating state t1 Time of 1st self-diagnosis t2 Time of the 2nd self-diagnosis Tsetpoint setpoint temperature T1 Minimum first temperature range T2 Maximum first temperature range T3 Minimum second temperature range T4 Maximum second temperature range Ta first measured value Tb second measurement

Claims

[1] Medical device (1) with means (3) for switching the device (1) on and off, where switching on activates the device and puts it into an operating state, and switching off deactivates the device and ends the operating state, wherein the device (1) performs at least one safety-related function in the operating state using at least one operating parameter with a defined setpoint, characterized by , that the device (1) performs a first self-diagnosis after being switched on and before reaching the operating state and a second self-diagnosis after being switched off and before the end of the operating state, in each case checking the same operating parameter of the at least one operating parameter of the device (1) for deviations from the setpoint value, wherein a deviation of the operating parameter from the specified setpoint within a value range is stored by the device (1) as a tolerance, and a deviation outside the value range is stored by the device (1) as an error, where the first self-diagnosis is based on a first range of values ​​and the second self-diagnosis is based on a second range of values, the second range of values ​​being smaller than the first. [2] Medical device (1) according to the preceding claim, wherein the operating parameter is a voltage, a current, a fluid flow, a pressure, a quantity of light or a temperature. [3] Medical device (1) according to one of claims 1 or 2, wherein in the event that an error is stored, an optical or acoustic warning is generated. [4] Medical device (1) according to claim 3, wherein the warning is generated after a further switching on and before a further first self-diagnosis. [5] Medical device (1) according to claim 3 or 4, wherein the warning comprises a notice for the user of the device (1). [6] Medical device (1) according to claim 4, wherein the device (1) is not put into the operating state. [7] Medical device (1) according to any one of claims 3 to 5, wherein the warning is generated only in the case where an error is stored during the first and second self-diagnosis. [8] Medical device (1) according to any one of claims 3 to 5, wherein the warning is generated in the case where a tolerance is stored during the first self-diagnosis and an error is stored during the second self-diagnosis. [9] Medical device (1) according to any one of claims 1 to 8, wherein in the event that an error is stored, the device (1) does not immediately terminate the operating state after being switched off. [10] Medical device (1) according to any of the preceding claims, wherein no self-diagnosis takes place when the device (1) is deactivated. [11] Medical device (1) according to claims 1 to 10, wherein the second range of values ​​is at least 25% and in particular at least 50% smaller than the first. [12] Method for operating a medical device (1), comprising the steps - Switching on (41) the device (1) - Performing an initial self-diagnosis (42) in which at least one initial operating parameter is checked for deviation from a target value of the operating parameter, - Activating the device (1) and placing the device (1) into an operating state (44) - Switching off (45) the device (1) - Performing a second self-diagnosis (46) in which at least the first operating parameter is checked for deviation from a target value of the operating parameter, - Ending the operating state (48), wherein a deviation of the operating parameter from the setpoint within a value range is stored by the device (1) as tolerance and a deviation outside the value range is stored by the device (1) as error, where the first self-diagnosis is based on a first range of values ​​and the second self-diagnosis is based on a second range of values, the second range of values ​​being smaller than the first. [13] Method according to claim 12, additionally comprising the step of generating an optical or acoustic warning in the case where an error is stored after the second self-diagnosis.

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