FR2696645A1 - Insufflator for the treatment of a body cavity of a patient. - Google Patents

Abstract

Device for blowing medium into a body cavity, comprising a throttle member and an electromagnetically actuatable valve, a valve drive and, a pressure measuring device, characterized in that it is provided , in the driving path (13), a flow measuring device (20, 21) which generates a signal FR EEL representative of the flow during a cycle, in that there is provided a generator device (26) which generates a signal FT HEORIQUE representative of the average flow to be regulated during a cycle, and in that an AND circuit (33) is provided which, at the coincidence of the signal FR EEL and the signal FT HEORIQUE, respectively triggers the end of a phase of filling of a cycle and thus the start of a measurement phase of the next cycle.

Description

The invention relates to a device for insuf-

  flation of a medium in a body cavity, comprising a throttle and an electromagnetically operable valve in a path between a supply line and an outlet line, a valve control which, respectively, closes

  and opens the valve during a measurement phase

  at the beginning of a cycle and during the filling phase

  consecutive wise until the end of the cycle, a timing generator determining each time the duration of the measurement phase and a pressure measuring device, which generates an electric PREEL signal determining the pressure in the body cavity , signal that is provided,

  each time, during a measurement phase.

  A device of this type is known from the DE 3 000 218 C 2 The intermittent operation is determinant so that, through the insufflation channel, the pressure can be simultaneously determined in the body cavity La duration of the phase

  measurement and the filling phase is pre-determined

  born by means of a command by a device to rhythm.

  In order to influence the filling operation, several throttling bodies are provided which can intervene alternatively in the path of the pipes.

  and which have different hydraulic resistances

  Thus, the flow rate (Volume per unit of time) can only be modified in an approximate way, because these throttles are only one element of flow determination among many others. An optimization in the sense of a fastest possible filling of the body cavity, respecting medically predetermined limit parameters, is not possible.

  The object of the invention is therefore to create a device

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  the technique, which allows to perform an insufflation automatically as quickly as possible, while respecting, in a precise way, the

  predetermined limit parameters.

  This object is achieved by providing, in the driving path, a flow measurement device which generates a FREEL signal representative of the flow rate during a cycle, that there is provided a generating device, which generates a signal Representative of the average flow rate to be adjusted during a cycle,

  and that an AND circuit is provided which coincides with

  dence of the FREEL signal and the FTHEORIQUE signal,

  triggers respectively the end of a filling phase

  wise of a cycle and so, the beginning of a measurement phase

next cycle.

  The regulation of the average flow rate, thus averaged over a whole cycle, compensates for the interruption or the reduction of the flow required for the measurement of the pressure during the measurement phases. The average flow rate, which is automatically adjusted, therefore corresponds to a filling. uninterrupted with this regulated flow rate, which

  thus guarantees a very fast filling operation.

  In this case, the respect of the predetermined flow rate is regulated so precisely that there is no danger for the patient in normal operation. The desired average flow rate control automatically compensates for all the factors influencing the flow rate, such as in particular the difference in speed. decreasing pressure between the cavity of the

body and the supply line.

  Because the flow measurement device

  generates a FREEL signal that represents the volume being

  lant by the throttling member accumulated since the beginning of the filling phase of a cycle, and the fact that the generating device delivers a signal FTHEORIQUE which represents the volume of the medium that must flow in the path of the pipes, accumulated since the beginning of the measurement phase of a cycle, the increase of this

  volume per unit of time being adjustable, the

  signal processing and processing are clear and effective. Since the generating device has a first function generator for transmitting a signal Fmax whose increase per unit time is adjustable via a manually operable adjustment element, the generator device has a second generator of functions. functions for transmitting a signal F whose increase per unit of time is modified by a

  signal t P, which is established by a differentiating element

  according to the difference between a PREEL signal and a PTHEORIC signal, the increase being zero for a zero difference and becoming steeper with increasing difference and,

  that the generating device has a control

  selection, which provides the smallest signal value of the signal F or the signal Fmax as an ETHEORIQUE signal, it can be performed a "filling of

  departure "taking place with the pre-determined maximum

  manually, in which case the maximum value is

  predetermined by the physician from a medical point of view.

  As soon as the pressure in the body cavity reaches a zone close to the theoretical pressure, it is automatically switched to a "final filling", where the filling phases become shorter and shorter, until produce more than

  filling when the theoretical pressure is reached.

  Considering that the flow measuring device has a calculation unit, which receives an input signal representing a pressure drop by the throttle bodies, from which the calculation unit determines the corresponding respective flow rate and the delivers in the form of the FREEL signal, it is possible to use pressure sensors which, according to the current technology, detect very fine pressure differences and thus make it possible to calculate the flow rate more accurately than is possible with measuring instruments

direct debit.

  According to the preferred configuration of the invention in which the valve is also used as an organ

  the existing valve which

  At the same time, a throttling action is used as a throttling device. This reduces the expense and avoids additional resistance reducing the flow rate.

  higher peak for a given inlet pressure.

  The configuration in which is arranged between the valve and the outlet pipe, an accumulator for the medium to be blown, the pace of the pressure in the accumulator being evaluated during the measuring phase to determine each time the pressure in the body cavity, shows a way of determining the pressure as described in DE 4,019,239. In this case, by three measurements of the pressure in the following, during the measurement phase, the following is identified: the curve of the pressure drop, from which, without having to wait for the static compensation of the pressure, the pressure of the body cavity is calculated in advance in the static state. can be considerably reduced compared to the known principle according to the DE 3 000 218 C 2 cited in

  introduction, according to which it is necessary to wait for

  pressure to measure the effective pressure.

  The accumulator required for this "dynamic pressure measurement" needs to maintain a decreasing flow rate (exponentially) that the time to perform the three pressure measurements Plus the measuring element of the available pressure is accurate and the resolution of the measurement good, the more the pressure measurements can be performed afterwards at increasingly short intervals Thus, for a self-compressible medium (gas), a tube or a piece of flexible pipe 10 cm long can

  already serve as sufficient accumulation volume.

  Various other features of the invention

  come out from the detailed description which

follows.

  Forms of realization of the object of the invention

  are represented, as non-limitative examples

in the accompanying drawings.

  FIG. 1 is a circuit of principle of a

device according to the invention.

  Figure 2 is a diagram as a function of time

  to illustrate the operation of the device.

  In the following description, it is presumed,

  for the sake of simplicity that the medium to be blown is gas (in particular C 02). In accordance with FIG. 1, a gas cartridge 10 supplies a supply line 12, via a pressure reducer 11, in

  gas that is here available at a set pressure Pmax -

  In the course of the pipe 13 which follows, there is a throttle member 14 and an electromagnetically operable valve which can close and open the pipe to connect it to a subsequent accumulator 16. The output of the accumulator 16 leads to an outlet pipe 17 to which is connected an insufflation needle 19 via a flexible pipe 18 The path of the pipe for the gas

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  is highlighted by lines in strong lines, at the

  difference of the electric lines.

  Thus, on both sides of the throttle member 14, a differential pressure sensor 20 is impacted by the gas and provides an electrical signal corresponding to the pressure drop at the throttle member 14, to a computing unit 21 which, at

  from there, taking into account the hydraulic resistance

  1 or the pressure drop of the throttling element 14, calculates the flow rate through the throttling element and expresses it by the signal FTHEORIQUE The sensor of

  differential pressure 20 and the computation unit 21 con-

  constitute a flow measuring device.

  The pressure P in the accumulator 16 is converted

  by a pressure converter 22 into an electrical signal, which is analyzed by a pressure measuring device 23 described in more detail in DE 4019 239 A1, to generate from there a signal

  PREEL, which represents the extra pressure

  polished from the original curve of the curve, into the abdominal cavity, after the pressure compensation

  between the battery and the abdominal cavity.

  The signal PREEL and a signal PTHEORIQUE, taken by a manually adjustable theoretical value indicator 24, are input into a differentiating element 25 which, from there, forms a signal A P. A generating device 26 consists of a first, a second function generator 27, 28 and a selection control 29 The first function generator 27 transmits a linear growth value signal Fmax with time, always starting from zero, as is explained again with the help of fig 2 In this case, the increment per unit of time can be modified via a setting element

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  Manual 30 The second function generator 28 transmits a signal F of growth value that is also linear with time, always starting from zero, as is

  also explained in more detail using fig 2.

  In this case, the increment per time unit is variable according to the LP signal and this so that

  for a P zero, the signal F also remains at zero (-

  no increase) and that, for an increasing value of A P, an increasingly rapid increase

is carried out.

  The selection control 29 then delivers

  the smaller of the two signals F and Fmax as

signal FTHEORIQUE-

  A valve control 31 comprises an amplification

  controller 32 which drives the magnetic coil of the valve 15 and an AND circuit 33, which receives the signal FREEL and the signal FTHEORIC If these signals coincide, the AND circuit 33 triggers a control signal S which causes the start of a new cycle,

  in a way that will be described.

  Since various functions take place as a function of time, a generator of

  rhythm or clock 34, which acts both on the device

  generator 26 only on the valve control 31.

  If analog signals are processed, then depending on the signal value, they are correspondingly high voltage values. In the case of digitally encoded signals, the value appears in binary characters. In the following diagram of FIG.

  signal values are represented in analog form

  for a better understanding.

  It is understood that in the case of digital signal processing, most of the circuits and devices mentioned above take place as "organization programs", in which a homogeneous hardware executes, being controlled by program,

  different operations shifted in time.

  In FIG. 2a, the curve of the pressure P depends on

  The time in the accumulator 16 is shown for several cycles. FIG. 2b illustrates the flow rate F., in particular FREEL. In FIG.

  V gas is shown as a function of time t.

  The pressure P in the accumulator 16 can reach

  When the valve 15 is open, at most the predetermined limit value Pmax by the expander 11 This state is found at the beginning of the time scale At the time tol, a new cycle begins with the beginning of a measurement phase , so the valve 15 closes In

  consequence, the accumulator is exponentially empty

  the asymptote of the curve here representing the pressure occurring last in the static state at the moment of pressure compensation, in the body cavity. But, we do not need to wait for this state. identify the shape of the curve using three pressure measurements symbolized by points on the curve A curve system is stored in a model memory, which is part of the device 23 for measuring the pressure A identification of one of the curves, the pressure measuring device delivers the corresponding value of PREE Lo In FIG. 2 a, it can be recognized that firstly PREE Lo is still very far from PTHEORIC The measurement phase lasts approximately

  0.2 sec and ends at the moment.

  At time t11, a filling phase begins with the opening of the valve 15. The pressure P in

  the accumulator 16 rises rapidly to Pmax (FIG. 2 a).

  Since the pressure difference with respect to the still very low pressure in the body cavity is PREE Lo, a high flow FREE Lo (fig 2 b) can be formed during the filling phase The purpose of the regulation consists, during "initial filling", of setting a homogeneous mean flow Fmax over the whole duration of a cycle If the duration of the measurement phase is fixed and if the magnitude of the flow FREEL depends substantially on the difference of pressure and hydraulic resistance, the regulation intervenes by

  automatically vary the duration of the filling phase

  To do this, according to fig 2 c, the generation at time t Ol of the signal Fmax starting at zero is started. At the moment til, the signal FREE Lo occurs.

  at the opening of the valve 15, and increases with the flow

  As the flow rate is equal to the volume of gas V per time unit t, the diagrams for imax and FREE Lo in the V-t diagram are

  represented by lines of origin in tol, respectively

  til, and of different steepness of the slope

  of intersection of the two lines, the condition FREE Lo -

  Fmax is full This state is registered by the circuit

  ET 33, which indicates on this the end of the phase of filling

  wise and so the end of the cycle in progress so far.

  This state corresponds to the beginning of a new phase

  measuring a new cycle at the moment to 2.

  After completion of the measurement phase at time t 12, a reduced flow rate FREEL 1 occurs because the pressure difference with respect to the body cavity has become smaller due to the previous filling In the diagram of FIG. right for

  FREEL 1 is therefore a little less inclined than before.

  As a result, the point of intersection with the straight lines Fmax starting at t O 2 occurs this time later, so that the filling phase lasts longer in

  compensation of a lower FREEL rate.

  This process is repeated in the following cycles in a similar way, more FREEL decreases constantly with increasing degree of filling of the cavity of the

  body, the longer the filling time.

  Following the example of the fourth cycle, the formation of

  the average value is represented again.

  The magnitude of the FREEL 4 X t F 4 surface is equal to the

surface Fmax x t Z 4-.

  In the diagram of FIG. 2, only the principle of the operation is represented.

  Absolutes and the time relationships are different.

  Thus, the measurement phase is mostly shorter than the filling phase. However, if the

  real reports are represented, we can no longer repro-

  in the format of the drawing several cycles differ

  This is obvious when you think that a cycle can actually last up to several seconds compared to a measurement phase that lasts

maximum one second.

  Heretofore, the course of the adjustment during "initial filling", in which

  it's about filling the body cavity the fastest-

  As a medical criterion, the values of Pmax and Fmax are here predetermined, the value Fmax which has been transmitted until now as a reference quantity FTHEORIC by the selection control 29 Assuming that the

  doctor leaves the setting of the regulator unchanged.

  ge, the increase of the straight lines Fmax then remains identi-

than at each cycle.

  However, as soon as the pressure in the body cavity approaches the set theoretical value PTHEORIQUE, another "final filling" procedure is performed in which the smaller the AP difference, the smaller the reference quantity FTHEORIQUE. Here, the criterion is the signal F according to FIG. 1 As long as its signal value is greater than that of the signal Fmax, the latter will be used as a reference variable FTHEORIQUE But as soon as the signal F, whose rise as a function of time is a function of AP, is equal to or less than Fmax signal, F resumes

the command.

  In FIG. 2c, the straight line Flo has a growth rate which is much lower than that of the straight line Fmax. Consequently, the point of intersection of the lines Flo and FREEL 10 lies in the time closer to the time til O, although the slope of the right FREE Ll O

  is even lower than in previous cycles.

  This is why the filling phase is now considerably shortened, in which case with the value FREE LL O lower, it results in a medium flow Flo

  corresponding lower for this cycle.

  In the next eleventh cycle, PREEL 11 is even closer to PTHEORIQUE, with the result that the filling phase from t111 to t 012 is even shorter In this way, the compensation of PREEL to PTHEORIQUE is brought very smoothly, without the risk of exceeding the objective As soon as we have PREEL PTHEORIQUE, the growth of the signal F is zero, that means that its value remains at zero, so that a measurement phase is immediately followed by another measurement phase As appropriate, a monitoring circuit can be activated here, which has the consequence that

  a laying interval of possibly 500 ms is inter-

pose.

  When a loss of pressure occurs in the body cavity, it is recorded in the phase

  following measurement and according to the magnitude of the

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  this triggers again a filling phase of appropriate duration, so that the theoretical pressure

is reached automatically.

  In the example of FIG. 1, the throttle member

  14 is shown as a separate element. However, the valve 15 also represents a throttling element, even if at its construction we are looking for

  a hydraulic resistance as small as possible.

  But using enough pressure sensors

  as they are already available today.

  This weak throttling effect can also be used to determine the flow rate.

  not use a valve acting as a foreign

  but a normal valve and thus another limitation of the maximum flow rate is

  anyway is already restricted by the insufflation needle.

  tion. The present regulation illustrated is independent of the principle according to which the pressure is determined

  in the body cavity is in the state of compensation

  static pressure according to DE 3 000 218 C 2, ie in the state of dynamic interpolation

DE 4,019,239 Ai.

  The aforementioned valve is representative for such elements with which the flow can be influenced in a comparable manner, for example with the aid of a

controlled pressure regulator.

Claims (6)

  Apparatus for blowing medium into a body cavity, comprising a throttle member and an electromagnetically operable valve in a path between a supply line and an outlet line, a valve control which, respectively, closed   and opens the valve during a measurement phase   at the beginning of a cycle and during the filling phase   consecutive wise up to the end of the cycle, a clock generator or clock determining each time the duration of the measurement phase and a pressure measuring device, which generates an electric PREEL signal determining the pressure in the cavity of the body, which signal is provided, each time during a measuring phase, characterized in that a flow measuring device (20, 21) is provided in the driving path (13) which generates a FREEL signal representative of the flow rate during a cycle, in that there is provided a generator device (26) which generates a FTHEORIC signal representative of the average flow rate to be adjusted during a cycle, and that an AND circuit (33) is provided which, at the coincidence of the signal FREEL and the signal FTHEORIQUE, respectively triggers the end of a filling phase of a cycle and thus, the beginning of a phase next cycle measurement.   2 Device according to claim 1, characterized   in that the flow measuring device (20, 21)   generates a FREEL signal that represents the volume being   lant by the throttle member (14) accumulated from the beginning of the filling phase of a cycle and, in that the generating device (26) generates a signal FTHEORIQUE which represents the volume of the medium that must flow in the path of the pipe (13),   accumulated since the beginning of a measurement phase,   this volume per unit of time being adjustable.   3 Device according to claim 2, characterized   characterized in that the generating device (26) has a first function generator (27) for transmitting a signal Fmax whose increment per unit of time is adjustable via a manually operable adjusting element (30). in that the generating device (26) has a second function generator (28) for outputting a signal F whose increase per unit time is modified by a signal t P, which is set by a differentiating element ( 25) according to the difference between a PREEL signal and a PTHEORIQUE signal, the increase being zero for a zero difference and becoming steeper with increasing difference and in that the generating device (26) has a selection control (29) , which provides the smallest signal value of signal F or signal Fmax in as signal FTHEORIQUE-   4 Device according to claim 1, characterized   in that the flow measuring device has a calculation unit (21) which receives an input signal   representing a pressure drop by the foreign   the calculation unit determines the corresponding respective flow rate and delivers it FREEL signal.   Device according to Claim 1, characterized in that the valve (15) is used at the same time as a throttling organ.   Device according to claim 1, characterized 2696645   in that an accumulator (16) for the medium to   insufflation is arranged between the valve (15) and the   output die (17), the pace of the pressure in the accumulator (16) being evaluated during the measurement phase to determine each time the pressure in the body cavity.   7 Device according to one of claims 2, 4   or 6, characterized in that the throttle member (14) is disposed between the supply line (12) and the valve (15).