ANESTHESIA PROCEDURE AND ASSOCIATED EQUIPMENT

Abstract

The invention relates to an anaesthesia procedure and associated anaesthetic equipment (3). In said procedure, a first respiratory gas (G1) is supplied to an anaesthetized patient (15) through a ventilator (3) with unidirectional flow or rapidly alternating flow direction. At least one adjustment parameter (F) of the ventilator (3) is controlled or regulated in such a manner that a current position (LA) of at least one body part (36) of the patient (15) is adjusted to a specified desired position (LS).

Claims

1. An anesthesia procedure comprising: supplying a patient whose own respiratory drive is suspended by a ventilator with a first respiratory gas with a unidirectional flow or rapidly alternating flow direction; and controlling at least one adjustment parameter of the ventilator in such a way that a current location of at least one body part of the patient is adjusted to a specified desired location.

2. The anesthesia procedure of claim 1, wherein the at least one adjustment parameter of the ventilator is controlled in such a way that the specified desired location is adjusted to a specified temporal desired path.

3. The anesthesia procedure of claim 1, wherein the specified desired location is specified based on a schedule of a device for irradiation.

4. The anesthesia procedure of claim 3, wherein the device for irradiation is movable, wherein the anesthesia procedure further comprises: performing a regulated adjustment of the specified desired location; and moving a the device for irradiation.

5. The anesthesia procedure of claim 3, further comprising: adjusting a control parameter of the device for irradiation a function of the current location.

6. The anesthesia procedure of claim 1, wherein the patient is arranged on a movable patient supporting device, wherein the current location of the at least one body part of the patient is adjusted to the specified desired location at least partially by a movement of the patient supporting device.

7. The anesthesia procedure of claim 1, wherein a flow rate, a pressure, an oxygen concentration, or a modulation of the flow rate or of the pressure of the first respiratory gas is controlled as the adjustment parameter of the ventilator.

8. The anesthesia procedure of claim 1, wherein the specified desired location of the body part is determined based on a default image data set of the body of the patient.

9. The anesthesia procedure of claim 8, further comprising: generating a current image data set of the body of the patient; determining the current location of the body part based on the current image data set; and changing the adjustment parameter of the ventilator in such a way that the current location of the body part approaches the specified desired location.

10. The anesthesia procedure of claim 1, wherein the specified desired location of the body part is determined indirectly based on a desired position of at least one marking provided in or on the patient.

11. The anesthesia procedure of claim 10, further comprising: determining a current position of the at least one marking; and wherein the adjustment parameter of the ventilator is changed in such a way that the current position of the at least one marking approaches its desired position.

12. The anesthesia procedure of claim 1, further comprising: starting, following adjustment of the current location of the body part to the specified desired location, image acquisition of the body of the patient.

13. The anesthesia procedure of claim 12, wherein at an end of or during an interruption to the image acquisition of the patient, ventilation is continued with a second respiratory gas with a slowly alternating flow direction.

14. A system comprising: a ventilator, which in a first operating mode is configured to supply a patient, whose own respiratory drive is suspended, with a first respiratory gas with unidirectional flow or rapidly alternating flow direction; and a control unit that is configured to control or regulate at least one adjustment parameter of the ventilator to adjust a current location of at least one body part of the patient to a desired location.

15. The system of claim 14, wherein the control unit is configured to control or regulate at least one adjustment parameter of the ventilator to adjust the desired location to a specified temporal desired path.

16. The system of claim 15, wherein the control unit is configured to specify the desired location based on a schedule of a device for irradiation.

17. The system of claim 16, wherein the control unit, on irradiation of the at least one body part of the patient by a movable device for irradiation, is configured to perform a regulated adjustment of the specified temporal desired path and of a movement trajectory of the device for irradiation.

18. The system of claim 15, wherein the control unit is configured to adjust a control parameter of the movable device for irradiation during an irradiation of the at least one body part of the patient, as a function of the current location.

19. The system of claim 14, wherein the control unit is configured to adjust the current location of the at least one body part of the patient, who is arranged on a moveable patient supporting device, to the desired location at least partially by a movement of the patient supporting device.

20. The system of claim 14, wherein the control unit is configured to control or regulate at least one of a flow rate, a pressure, an oxygen concentration, or a modulation of the flow rate or of the pressure of the first respiratory gas as an adjustment parameter of the ventilator.

21. The system of claim 14, wherein the control unit is configured to determine the desired location of the body part based on a default image data set of the body of the patient.

22. The system of claim 14, wherein the control unit is configured to determine the desired location of the body part based on a desired position, detected by a tracking mechanism, of at least one marking provided in or on the patient.

23. The system of claim 14, wherein the control unit, following adjustment of the current location of the body part to the desired location, is configured to start or enable image acquisition of the body of the patient or an intervention inside the body of the patient.

24. The system of claim 23, wherein the ventilator, in a second operating mode, is configured to supply the patient with a second respiratory gas, with slowly alternating flow direction, wherein the control unit is configured to switch over the ventilator from the first operating mode into the second operating mode at an end of or during an interruption to the image acquisition or the intervention.

25. (canceled)

26. (canceled)

Description

BRIEF DESCRIPTION OF THE FIGURES

[0062] FIG. 1 depicts in a schematic block diagram anesthesia equipment with a ventilator for ventilating a patient and with a control unit; a medical imaging device in the form of an X-Ray C-arm system and an optical tracking system with which the anesthesia equipment interacts according to an embodiment.

[0063] FIG. 2 depicts in a schematic simplified flow diagram an anesthesia procedure carried out by the anesthesia equipment according to FIG. 1 for ventilation of an anesthetized patient during acquisition of a medical 3D image data set according to an embodiment.

[0064] FIG. 3 depicts in more detail in a representation according to FIG. 2 a step of the method there in which an adjustment parameter of the ventilator is regulated in such a way that a current location of a body part of the patient is adjusted to a specified desired location according to an embodiment.

[0065] FIG. 4 depicts in a representation according to FIG. 2 a further application of the anesthesia procedure for ventilation of an anesthetized patient during an image-assisted intervention according to an embodiment.

[0066] FIG. 5 depicts in a schematic block diagram anesthesia equipment with a ventilator for ventilation of a patient arranged on a patient supporting device, with a control unit and a movable device for irradiation according to an embodiment.

DETAILED DESCRIPTION

[0067] FIG. 1 depicts in a schematic block diagram anesthesia equipment 1 with a ventilator 3 and a control unit 5. FIG. 1 also depicts a medical imaging device 7, that includes a (X-ray) C-arm 9 and an image computer 11. Optionally, an optical tracking system 13 is also present. The imaging device 7 and the tracking system 13 interact here with the anesthesia equipment 1 but do not themselves form an integral part of the latter.

[0068] In an embodiment, the ventilator 3 of the anesthesia equipment 1 is formed by a THRIVE ventilator that is conventional per se, that is configured to supply a patient 15 with a respiratory gas G1. For example, the patient 15 is supplied here with pure oxygen with a high flow rate F, unidirectionally and in a manner unmodulated over time, as the respiratory gas G1. The flow rate F may be adjusted here within a medically safe range, for example between 50 liters per minute and 90 liters per minute. The respiratory gas G1 is supplied to the patient 15 via the nose or alternatively via a ventilation tube (endotracheal tube). The supply of the respiratory gas G1, that is unmodulated over time, leads to motionless ventilation of the patient 15, in other words it does not cause any lasting movement of the patient's body.

[0069] In an embodiment, the ventilator 3, in addition to the THRIVE ventilator, includes conventional anesthesia equipment, that is configured to supply the patient 15 with a respiratory gas G2 with periodically alternating gas flow direction. Using this conventional anesthesia equipment, the ventilator 3 carries out conventional motion ventilation in which the gas flow direction of the respiratory gas G2 is slowly, with a frequency corresponding approximately to the natural respiratory rhythm, and actively alternated. The ventilator 3 generates a body movement corresponding to the customary respiratory movement of the patient 15 in which thorax and abdominal wall of the patient 15 periodically rise and fall and the internal organs in the chest area and abdominal region of the patient periodically change their position owing to the varying lung volume.

[0070] The respiratory gas G2 is a mixture of pure oxygen and nitrogen gas or purified ambient air with an oxygen content that substantially matches the customary oxygen content of air or is slightly raised compared thereto. Optionally, a proportion of the anesthetic, for example laughing gas (nitrous oxide, N.sub.2O) is also added to the respiratory gas G2.

[0071] In order to produce the respiratory gases G1 and G2 the ventilator 3 includes connecting lines 17 for oxygen O2, nitrogen N2 or air and laughing gas N2O, that are fed from a supply network of a hospital and/or from corresponding gas bottles.

[0072] Optionally, the anesthesia equipment 1 also includes an injection device (not shown), that is configured to inject the patient 15 with a liquid anesthetic.

[0073] The C-arm 9 of the imaging device 7 is configured to acquire digital (X-ray) projection images P of the inside of the body of the patient 15 from different perspectives and to transfer them to the image computer 11. The image computer 11 is configured to calculate a digital (3D) image data set B of the inside of the body of the patient 15 from these projection images P using conventional image reconstruction algorithms.

[0074] The tracking system 13 includes a (3D) camera 21 with an electronic image processing device, that is configured to determine the position M in the three-dimensional space of a plurality of (adhesive) markings 23 provided on the body of the patient 15 from images acquired by the 3D camera 21.

[0075] The control unit 5 is formed, for example, by a computer (for example a personal computer). A control program 19 is installed to be executable in the control unit 5 and automatically carries out an anesthesia procedure described below. The projection images P and 3D image data sets B of the patient 15 as well as the positions M of the adhesive markings 23, if present, determined by the tracking system 13 are supplied as input variables to the control unit 5 by the image computer 11 of the imaging device 7.

[0076] The control unit 5 in turn actuates the ventilator 3 as well as, optionally, the imaging device 7.

[0077] FIG. 2 schematically represents one embodiment of the anesthesia procedure carried out by the anesthesia equipment 1 in an application in which the anesthesia procedure for ventilation of the patient 15 is used during acquisition of a medical (3D) image data set B2 (generally also referred to as a “scan”) of the inside of the body by the imaging device 7. This imaging acquisition is, for example, a follow-up scan, that is carried out as an interval of, for example, several days or weeks, after a first scan, in other words a first (3D) image data set B1 acquired in advance, in order, for example, to document the course of a disease or a therapy. To provide the comparability and/or simple ability to register the image data sets B1 and B2 it is regularly of great importance that the image data sets B1 and B2 map the inside of the body of the patient 15 at an interval that is a similar as possible, and this is complicated by the respiration-induced body movement of the patient 15.

[0078] Only the method steps, that are entered in the diagram according to FIG. 2 as rectangles denoted by solid lines, form part of the actual anesthesia procedure. Further measures, that do not form part of the anesthesia procedure but merely provide input data for this procedure or are carried out at the same time as the anesthesia procedure, are represented in FIG. 2 as rectangles denoted by dotted lines. Arrows denoted by solid lines identify a successive implementation of the method steps connected therewith. Arrows denoted by dot-dash lines represent a transfer of data and other signals.

[0079] In the application case according to FIG. 2, the image data set B1 is acquired, for example, by the imaging device 7, as a preparatory action before implementation of the anesthesia procedure. To avoid movement artifacts during image acquisition the image data set B1 is acquired optionally under anesthesia and deactivation of the respiratory movement of the patient 15. For this, the patient 15 is anesthetized in a step 27, for example by anesthesia equipment 1, and is motionlessly ventilated by THRIVE (as described above) with the respiratory gas G1 at a specified flow rate of, for example, 70 liters per minute.

[0080] As soon as the anesthetized test state is achieved, image acquisition (step 25) is automatically started or provided for manual implementation. In the first case, for example the control unit 5 of the anesthesia equipment 1 emits in a step 29 a start signal S to the imaging device 7, which thereupon automatically begins the image acquisition. In the second case, the control unit 5 outputs the start signal S, for example via a connected screen 31 (see FIG. 1), in order to signal enabling of image acquisition to a radiologist carrying out the treatment.

[0081] After the image data set B1 has been acquired, an end signal E is returned to the control unit 5—automatically by the imaging device 7 or manually by the radiologist—which thereupon cancels the anesthesia in a step 33.

[0082] During the course of the anesthesia procedure, that according to FIG. 2 is carried out in accompaniment to the follow-up scan, in other words the acquisition of the subsequent image data set B2 (step 35), the control unit 5 determines initially in a step 37 a desired location LS of a body part 36 (see FIG. 1) of the patient 15, for example of a lobe of the lung, from the image data set B1 used here as the default image data set. For this, a 2-dimensional projection representation according to a specified characteristic perspective is derived, for example from the 3D image data set B1. The contour of the body part 36 is then determined in this projection representation using methods of automatic image recognition, for example segmentation. For example, the coordinates of the determined contour line, that for comparability are indicated relative to the stationary body structures, are used as the desired location LS.

[0083] The anesthesia is then (alternatively before or at the same time as step 37) initiated (step 27) by the anesthesia equipment 1 as described above.

[0084] In a subsequent step 39, the control unit 5 induces the imaging device 7 to acquire a current image data set of the inside of the body of the patient 15 (step 41) by emitting a request signal A once or several times. The current image data set is acquired, for example by the C-arm 9, as a two-dimensional projection image PA from the same perspective, that formed the basis of the creation of the projection representation in step 37 and determination of the desired location LS, therefore (step 41).

[0085] Analogously to step 37, the control unit 5 determines from the projection image PA the contour of the body part 36 (for example here the lobe of the lung, therefore) and determines a current location LA of the body part 36 hereby.

[0086] The control unit 5 changes an adjustment parameter of the ventilator 3, for example the flow rate F (FIG. 1) of the respiratory gas G1, on the basis of the difference D of the current location LA of the body part 36 from the desired location LS, so the current location LA is adjusted to the desired location LS. For example, the flow rate F is increased, so the lobe of the lung used as the body part 36 is inflated to a volume corresponding to the state in image data set B1.

[0087] Furthermore, the adjustment parameter F of the ventilator 3 may be controlled or regulated in such a way that the specified desired location LS is adjusted to a specified temporal desired path PS. The specified temporal desired path PS may include a plurality of desired locations LS, that may be achieved, for example in a chronological sequence, by an adjustment of the current location LA.

[0088] As soon as this adjustment has been made the control unit 5 outputs the start signal S (step 29) to start or provide the follow-up scan and therewith the acquisition of image data set B2 (step 35). On the end signal E, that announces completion of the follow-up scan, the control unit 5 then in turn ends the anesthesia (step 33).

[0089] In step 39, described above in a very simplified manner, the control unit 5 carries out, in detail, an iterative closed-loop control shown in more detail in FIG. 3.

[0090] In a first step 43 of this closed-loop control, the control unit 5 induces the imaging device 7 to acquire the current projection image PA (step 41) by emitting the request signal A. On the end signal E (for example automatically generated by the imaging device 7), the control unit 5 determines in a step 45 the current location LA of the body part 36 by evaluation of the projection image PA (for example by automatic segmentation).

[0091] In a following step 47, the control unit 5 determines the difference D of the current location LA from the desired location LS. As a measure for the difference D the control unit 5 uses, for example, the size of the non-overlapping surface areas within the contour lines of the body part 36 extracted from the image data set B1 and the current projection image PA. The control unit 5 tests the difference D in a step 49 in respect of a specified termination criterion, for example for undershooting a specified tolerance limit. As soon as the termination criteria is met (Y), if the difference D undershoots the tolerance limit, therefore, the control unit 5 ends the closed-loop control.

[0092] Otherwise (N), in a step 51, the control unit 5, by appropriate actuation of the ventilator 3, induces the change in the flow rate F. The control unit 5 determines the size and direction of this change, for example according to the Newton method. The flow rate F is changed, for example, in such a way that, as a consequence of the changed flow rate F, the current location LS of the body part 36 approaches the desired location LA. The control unit 5 then jumps back to step 43 and runs through the closed-loop control again, therefore.

[0093] FIG. 4 depicts another application case of the anesthesia procedure in which this is used for ventilation of the patient 15 during an image-assisted medical intervention.

[0094] Parallel to the anesthesia procedure, but not as part of it, firstly a first scan (step 25) is carried out. The image data set B1 resulting therefrom is used for treatment planning (step 53). The actual intervention (step 55), for example the introduction of a catheter into the upper body of the patient 15, is performed according to the treatment planning. In order to check the success of treatment a follow-up scan (step 35) is finally again performed.

[0095] An optimally uniform location of the organs and other body parts in the chest area and abdominal region of the patient 15 is in turn required for steps 25, 55 and 35. However, motionless ventilation of the patient 15 is often not possible for the entire duration of steps 25, 53, 55 and 35. During the course of the anesthesia procedure, the control unit 5 repeatedly switches the ventilator 3 back and forth between the operating modes of motionless ventilation (THRIVE) and conventional motion ventilation.

[0096] In detail, the anesthesia equipment 1 initially anaesthetizes the patient 15 (step 27) by motionless ventilation (THRIVE) and induces the first scan (step 25) in step 29.

[0097] Upon receiving the end signal E, the control unit 5 switches the ventilator 3 in a step 57 for the duration of the treatment planning (step 53) from motionless ventilation (THIRVE) to motion ventilation.

[0098] Completion of treatment planning is signaled to the control unit 5 by a (for example manually generated) further end signal E. Hereupon the control unit 5 switches over the ventilator 3 again in a step 59 from motion ventilation to motionless ventilation (THRIVE) and adjusts the current location LA of the body part 36 by carrying out steps 37 and 39 by regulation of the flow rate F to the desired location LS derived from the image data set B1.

[0099] In a step 61, the control unit 5 then provides implementation of the intervention (step 55) by emitting the start signal S once again.

[0100] After receiving the end signal E, that in this case indicates completion of the intervention, the control unit 5 switches over the ventilator 3 again from motionless ventilation (THRIVE) to motion ventilation (step 57), for example to reduce an elevated CO.sub.2 concentration in the blood of the patient 15.

[0101] For implementation of the follow-up scan, control unit 5 switches over (step 59) the ventilator 3 again at a subsequent instant from motion ventilation to motionless ventilation (THRIVE), adjusts the current location LA of the body part 36 again by regulation of the flow rate F to the desired location LS derived from the image data set B1 (steps 37 and 39) and with renewed implementation of step 29 induces the follow-up scan, for example the acquisition of image data set 2 (step 35).

[0102] After completion of acquisition and reception of the corresponding end signal E the control unit 5 then in turn ends the anesthesia (step 33).

[0103] In an embodiment of the anesthesia procedure (not shown), the desired location LS of the body part 36 is not determined from a default image data set. Instead, the position M of the adhesive markings 23 on the body of the patient 15 is determined by the tracking system 13 here, for example at the instant of a first scan, as an indirect reference (desired position MS, see FIG. 1) for the desired location LS.

[0104] For regulated adjustment of the current location LA of the body part 36 to the desired location LS, for example analogous to step 39 in FIG. 2 before a follow-up scan, a current position MA (FIG. 1) of the adhesive markings 23 is determined during the anesthesia and motionless ventilation (THRIVE) of the patient 15 by the tracking system 13. For each adhesive marking 23, the control unit 5 determines the difference of the current position MA from the desired position MS and adjusts the adjustment parameter of the ventilator 3, for example the flow rate F, analogously to the closed-loop control in FIG. 3 in such a way that the current position MA of every adhesive marking 23 within specified tolerance limits is matched to the desired location MS. The current location LA of the body part 36 is also indirectly adjusted thereby to the desired location LS.

[0105] In a further embodiment of the anesthesia equipment 1, the ventilator 3, for example as an alternative to the THRIVE apparatus, includes a further ventilator for carrying out jet ventilation. During operation of this apparatus the respiratory gas G1 is applied to the patient 15 in pulses and at a high pulse frequency (compared to the customary respiratory cycle) into the airways that are open to the outside. In addition to the (gas) flow rate F, the pulse frequency of the gas pulses may also be set here within a medically safe range, for example between 0.5 Hz and 10 Hz. Optionally, the mean pressure of the respiratory gas G1, by which the instantaneous pressure of the respiratory gas G1 fluctuates as a consequence of the pulsed application, may be set in addition to the flow rate and/or the pulse frequency. A rapid movement with low amplitude—corresponding to the pulse frequency—is generated in the body of the patient 15 by the jet ventilation, which movement fundamentally differs from a customary respiratory movement of the body.

[0106] For example, air with a customary or slightly enriched oxygen content as well as the optional addition of at least one gaseous anesthetic is used as the respiratory gas G1 in this variant of the anesthesia equipment 1.

[0107] Within the framework of the anesthesia procedure, jet ventilation is used as the method of motionless ventilation instead of the THRIVE anesthesia used in the examples described above.

[0108] In a schematic block diagram FIG. 5 depicts anesthesia equipment 1 with a ventilator 3 for ventilating a patient 15 arranged on a patient supporting device 70, and a control unit 5. In the embodiment illustrated here, the desired location LS may be specified on the basis of a schedule of a device for irradiation VB. For this, the device for irradiation VB may include, for example, a control unit, that is configured to send a corresponding control command 72 to the control unit 5.

[0109] Furthermore, the device for irradiation VB may be moveable. Advantageously, a regulated adjustment of the desired location LS and a movement trajectory of the device for irradiation VB may take place hereby. Regulation by the control unit 5 by the specification of the adjustment parameter F and/or a control command 72 to the device for irradiation VB may be conducive for this.

[0110] Furthermore, a control parameter, for example an operating parameter of a movement and/or for control of an irradiation intensity, of the device for irradiation VB may be adjusted as a function of the current location LA. The schedule of the device for irradiation VB may include, for example, a spatial distribution of irradiation dose. An adjustment of the control parameter as a function of the current location LA ensures that the at least one body part 36 of the patient 15 may be irradiated in accordance with the specified schedule. Furthermore, it is possible to ensure that further body parts 36′ of the patient 15 are always arranged outside of a target area ZG of the device for irradiation VB.

[0111] In an embodiment, the patient supporting device 70, on which the patient 15 is arranged, may be moveable. As a result, the adjustment of the location LA of the at least one body part 36 of the patient 15 to the specified desired location LS may take place at least partially by the movement of the patient supporting device 70. For this, the control unit 5 may send a control command 73 to the patient supporting device 70. The movement of the patient supporting device 17 may take place, for example, semi-automatically and/or automatically.

[0112] It is to be understood that the elements and features recited in the appended claims may be combined in different ways to produce new claims that likewise fall within the scope of the present embodiments. Thus, whereas the dependent claims appended below depend from only a single independent or dependent claim, it is to be understood that these dependent claims may, alternatively, be made to depend in the alternative from any preceding or following claim, whether independent or dependent, and that such new combinations are to be understood as forming a part of the present specification.

[0113] While the present embodiments have been described above by reference to various embodiments, it may be understood that many changes and modifications may be made to the described embodiments. It is therefore intended that the foregoing description be regarded as illustrative rather than limiting, and that it be understood that all equivalents and/or combinations of embodiments are intended to be included in this description.