CN101756703B - Method for detecting expiratory humidity volumes and device using same - Google Patents

Abstract

The invention provides a method for detecting expiratory tidal volumes at a flow trigger of a ventilator and a device using the same. The method comprises the following steps: at the beginning of the action of expiration, detecting the first flow rate of gases inside inspiratory tubes of the ventilator, the second flow rate of gases inside the expiratory tubes of the ventilator and the pressure inside the expiratory tubes at a predetermined time interval at the same time; in accordance with the first flow rate and the second flow rate detected each time and the predetermined time interval, separately obtaining the expiratory tidal volume corresponding to each moment, wherein, the pressure detected each time is compared with the preset pressure, and the expiratory tidal volume at this time and the expiratory tidal volume in the expiratory phase at later time is set as 0 when the pressure is less than the preset pressure; and summarizing a plurality of expiratory tidal volumes to obtain the expiratory tidal volume of the whole inspiratory-expiratory phase. The invention realizes accurate measurement of the expiratory tidal volumes at the flow trigger of the ventilator.

Description

The detection method of expiration tidal volume and device

Technical field

The present invention relates to medical domain, more specifically, the detection method of the expiration tidal volume when relating to a kind of flow velocity that is used for respirator and triggering and the checkout gear of expiration tidal volume.

Background technology

The detection of the expiration tidal volume under flow velocity triggers is the control difficult point of respirator always, and current The common calculation methods is: adopt flow velocity that the integral and calculating of time is obtained the tidal volume of exhaling in whole expiratory phase.If inspiratory flow rate is F_In, exhalation flow rate F_Ex, expiratory duration T, expiration tidal volume V_T, then$V_T={\∫}_0^T(F_{\mathrm{Ex}}-F_{\mathrm{In}}),$This formula exhales flow velocity to subtract each other the back continuous flow to not influence of tidal volume according to suction.And in fact adopting the different flow rate pick off with exhaling owing to air-breathing, the flow speed data of collection must have error, so the result of integration often makes that breathing tidal volume error is very big, generally more than 20%.The flow process waveform of detected tidal volume of the prior art is as shown in Figure 1; With reference to Fig. 1; After exhale action was accomplished, the continuous flow influence made that a lot of spuious waveforms occur on the flow velocity waveform, when the integral and calculating tidal volume; In the error of spuious waveform all is calculated in, so the expiration tidal volume of calculating can not reflect practical situation truly.For example, when tidal volume 400ml was set, monitoring expiration tidal volume maybe be more than 500ml, and all there is relation the persistent period of these data and respiratory frequency, expiratory phase: respiratory frequency is low more, and expiratory phase time is long more, and error is just big more.

Summary of the invention

The object of the present invention is to provide a kind of detection method and device that under the flow velocity trigger condition, can accurately detect the expiration tidal volume that is used for respirator.

According to an aspect of the present invention; The detection method of the expiration tidal volume when providing a kind of flow velocity that is used for respirator to trigger; Comprise: when exhale action begins, detect second flow velocity of gas in the expiration pipeline of first flow velocity, respirator of gas in the aspirating air pipe of respirator and the force value in the expiration pipeline simultaneously with predetermined time interval; According to each detected first flow velocity of the moment and second flow velocity and predetermined time interval; Obtain respectively corresponding to each expiration tidal volume constantly; Wherein, Each detected force value and scheduled pressure value are compared, when force value during less than scheduled pressure value, this constantly and the expiration tidal volume that in expiratory phase, constantly obtains subsequently be set to 0; And to the tidal volume of a plurality of expiration tidal volumes summation with the expiration that obtains whole expiratory phase.

Wherein, can be through respectively each detected second flow velocity of the moment and first flow velocity being asked difference and the difference of second flow velocity and first flow velocity are carried out the integration acquisition corresponding to each expiration tidal volume constantly in the interval at the fixed time; And when force value during less than scheduled pressure value, this constantly and in expiratory phase subsequently constantly the difference of detected second flow velocity and first flow velocity be set to 0 and the expiration tidal volume is set to 0.

Preferably, predetermined time interval is 10ms.

Preferably, scheduled pressure value is 0.5 centimeter water column.

Preferably, detect first flow velocity and second flow velocity, and come the detected pressures value through pressure transducer through flow sensor.

According to a further aspect in the invention; A kind of expiration tidal volume checkout gear also is provided; Comprise: detection module; Be used for when exhale action begins, detect second flow velocity of gas in first flow velocity, expiration pipeline of gas in the aspirating air pipe in the respirator and the force value in the expiration pipeline with predetermined time interval simultaneously, and first flow velocity and second flow velocity in detected a plurality of moment is sent to processing module; Processing module; Be used for according to each detected first flow velocity of the moment and second flow velocity and predetermined time interval; Obtain the expiration tidal volume in each predetermined time interval respectively; And be used for each detected force value and scheduled pressure value are compared, when force value during less than scheduled pressure value, this constantly and the expiration tidal volume that in expiratory phase, constantly obtains subsequently be set to 0; And summation module, be used to store by the expiration tidal volume in a plurality of intervals that obtain after the processing module processing and to a plurality of expiration tidal volumes and sue for peace to obtain the expiration tidal volume of whole expiratory phase.

Wherein, processing module can comprise: ask the differential mode piece, be used for respectively each detected second flow velocity of the moment and first flow velocity being asked poor; Integration module is used for the difference of second flow velocity and first flow velocity is carried out the integration acquisition corresponding to each expiration tidal volume constantly in the interval at the fixed time; And relatively reach module be set, be used in force value during less than scheduled pressure value, this constantly and in expiratory phase subsequently constantly the difference of detected second flow velocity and first flow velocity be set to 0 and the expiration tidal volume is set to 0.

Preferably, predetermined time interval is 10ms.

Preferably, scheduled pressure value is 0.5 centimeter water column.

Preferably, detection module comprises flow sensor and pressure transducer.

Beneficial effect of the present invention is: through in testing process, adding pressure in the expiration road as Rule of judgment, eliminated that continuous flow makes that to the influence of expiration tidal volume the accuracy of detection of expiration tidal volume is higher under the flow velocity trigger condition.

Other features and advantages of the present invention will be set forth in specification subsequently, and, partly from specification, become apparent, perhaps understand by embodiment of the present invention.The object of the invention can be realized through the structure that in the description of being write, claims and accompanying drawing, is particularly pointed out and obtained with other advantages.

Description of drawings

Accompanying drawing described herein is used to provide further understanding of the present invention, constitutes the application's a part, and illustrative examples of the present invention and explanation thereof are used to explain the present invention, do not constitute improper qualification of the present invention.In the accompanying drawings:

The flow velocity waveform figure that the traditional technique in measuring that is to use Fig. 1 arrives;

Fig. 2 is the flow chart according to the detection method of the expiration tidal volume of the embodiment of the invention;

Fig. 3 is the block diagram of checkout gear of tidal volume of exhaling according to another embodiment of the present invention; And

Fig. 4 is according to the detected flow velocity waveform figure of the embodiment of the invention.

The specific embodiment

Below in conjunction with accompanying drawing the preferred embodiments of the present invention are described, should be appreciated that preferred embodiment described herein only is used for explanation and explains the present invention, and be not used in qualification the present invention.In full, same reference numerals is represented same apparatus.

Fig. 2 is the flow chart according to the detection method of the expiration tidal volume of the embodiment of the invention.

With reference to Fig. 2, may further comprise the steps according to the detection method of the expiration tidal volume of the embodiment of the invention:

Step S202 when exhale action begins, detects second flow velocity of gas in the expiration pipeline of first flow velocity, respirator of gas in the aspirating air pipe of respirator and the force value in the expiration pipeline simultaneously with predetermined time interval;

Step S204; According to each detected first flow velocity of the moment and second flow velocity and predetermined time interval; Obtain respectively wherein, each detected force value and scheduled pressure value being compared corresponding to each expiration tidal volume constantly; When force value during less than scheduled pressure value, this constantly and the expiration tidal volume that in expiratory phase, constantly obtains subsequently be set to 0; And

Step S206 is to the tidal volume of a plurality of expiration tidal volumes summation with the expiration that obtains whole expiratory phase.

Step S204 can comprise: through respectively each detected second flow velocity of the moment and first flow velocity being asked difference and the difference of second flow velocity and first flow velocity is carried out the integration acquisition corresponding to each expiration tidal volume constantly in the interval at the fixed time; And when force value during less than scheduled pressure value, this constantly and in expiratory phase subsequently constantly the difference of detected second flow velocity and first flow velocity be set to 0 and the expiration tidal volume is set to 0.

The difference of this moment and detected subsequently second flow velocity and first flow velocity is set to 0 and can comprises: this second flow velocity and first flow speed value constantly is set to equate; And in this expiratory phase, constantly stop detection subsequently to first flow velocity and second flow velocity, directly it is recorded as 0.Preferably, being set to equate is that it all is set to 0.

Predetermined time interval can be 10ms.

Scheduled pressure value can be according to being 0.5 centimeter water column.

Can detect first flow velocity and second flow velocity through the flow monitor of for example flow sensor, and can come detected pressures through the pressure-detecting device of for example pressure transducer.

Fig. 3 is the block diagram of checkout gear 300 of tidal volume of exhaling according to another embodiment of the present invention.

With reference to Fig. 3; The checkout gear 300 of the tidal volume of exhaling according to another embodiment of the present invention comprises: detection module 302; Be used for when exhale action begins; Detect second flow velocity of gas in first flow velocity, expiration pipeline of gas in the aspirating air pipe in the respirator and the force value in the expiration pipeline with predetermined time interval simultaneously, and first flow velocity and second flow velocity in detected a plurality of moment is sent to processing module 304; Processing module 304; Be used for according to each detected first flow velocity of the moment and second flow velocity and predetermined time interval; Obtain the expiration tidal volume in each predetermined time interval respectively; And be used for each detected force value and scheduled pressure value are compared, when force value during less than scheduled pressure value, this constantly and the expiration tidal volume that in expiratory phase, constantly obtains subsequently be set to 0; And summation module 306, be used to store by the expiration tidal volume in a plurality of intervals that obtain after processing module 304 processing and to a plurality of expiration tidal volumes and sue for peace to obtain the expiration tidal volume of whole expiratory phase.

Processing module 304 can comprise: ask the differential mode piece, be used for respectively each detected second flow velocity of the moment and first flow velocity being asked poor; Integration module is used for the difference of second flow velocity and first flow velocity is carried out the integration acquisition corresponding to each expiration tidal volume constantly in the interval at the fixed time; And relatively reach module be set, be used in force value during less than scheduled pressure value, this constantly and in expiratory phase subsequently constantly the difference of detected second flow velocity and first flow velocity be set to 0 and the expiration tidal volume is set to 0.

Predetermined time interval can be 10ms.

Scheduled pressure value can be 0.5 centimeter water column.

Particularly, detection module 302 can also comprise: flow sensor, be used for when exhale action begins, and detect second flow velocity of gas in first flow velocity and the expiration pipeline of gas in the aspirating air pipe in the respirator simultaneously with predetermined time interval; And pressure transducer, be used for when detecting first flow velocity and second flow velocity, detecting the pressure in the expiration road.

Wherein, detection module 302 is positioned at respirator inside, and the flow rate detection module comprises that at least two flow sensors in the aspirating air pipe that lays respectively at respirator and the expiration pipeline are to detect first flow velocity and second flow velocity respectively.

Owing to have continuous flow in the respirator, therefore remove continuous flow causes in second flow velocity flow velocity and eliminate and when asking the expiration tidal volume, need eliminate the influence of continuous flow the expiration tidal volume through deduct first flow velocity with second flow velocity.

Followingindex map 2 is explained an alternative embodiment of the invention with Fig. 4.

Fig. 4 is according to the detected flow velocity waveform figure of the embodiment of the invention.

With reference to Fig. 4,, in the process that detects the expiration tidal volume, added pressure judging point Plimit based on this embodiment.Therefore, the detection method step according to the embodiment of the invention is following:

When exhale action begins, detect second flow velocity of gas in the expiration pipeline of first flow velocity, respirator of gas in the aspirating air pipe of respirator and the force value in the expiration pipeline simultaneously with the predetermined time interval of 10ms;

Other to each constantly detected second flow velocity and first flow velocity is asked and to the difference of second flow velocity and first flow velocity at the 10ms integration; To obtain respectively corresponding to each a plurality of expiration tidal volume constantly; Wherein, Each detected force value and scheduled pressure value are compared, when force value during less than scheduled pressure value, this constantly and in expiratory phase subsequently constantly the difference of detected second flow velocity and first flow velocity be set to 0; And

To the tidal volume of a plurality of expiration tidal volumes summation with the expiration that obtains whole expiratory phase.

With this constantly and detected subsequently first flow velocity and said second flow velocity all be set to equate also can comprise: this first flow velocity and second flow speed value constantly is set to equate; And, directly it is recorded as 0 constantly stopping detection subsequently to first flow velocity and second flow velocity.Preferably, being set to equate is that it all is set to 0.

After above-mentioned testing process is accomplished; When calculating the expiration tidal volume; Because only the dash area to the flow velocity shown in Fig. 4 has carried out integration, promptly expiration is begun to reduce to the velocity integral between the Plimit to pressure, so eliminated the influence of continuous flow afterwards of this moment; Reflected tidal volume really, had no relation with parameter settings such as respiratory frequencys.Its another favourable influence that brings is exactly that flow velocity waveform is very level and smooth.According to test, when pressure reached the 0.5cm water column, the tidal volume that calculates relatively accurately, can think when pressure drops to the 0.5cm water column that exhale action is accomplished.

Particularly, integral process also can carry out as follows: expiratory duration T is divided into the n segment: Δ t1, Δ t2 ... Δ tn, i.e. Δ t1+ Δ t2+ ... + Δ tn=T.

In the Δ t1 time, gather flow velocity (F_Ex-F_In)₁, in the Δ t2 time, gather flow velocity (F_Ex-F_In)₂,

Then$V_T={\&Integral;}_0^T(F_{\mathrm{Ex}}-F_{\mathrm{In}})={(F_{\mathrm{Ex}}-F_{\mathrm{In}})}_1*\mathrm{\&Delta;\; t}1+{(F_{\mathrm{Ex}}-F_{\mathrm{In}})}_2*\mathrm{\&Delta;<figure-callout\; label="t"\; filenames="H2008102410700E00011.png,H2008102410700E00022.png"\; state="\{\{state\}\}">t</figure-callout>}2+......$$+{(F_{\mathrm{Ex}}-F_{\mathrm{In}})}_n*\mathrm{\&Delta;\; Tn}$

Δ tx (x=1,2,3 in the present embodiment ... N) be 10ms, this value also can adopt different values according to different control systems.

Pass through the foregoing description; The present invention has realized through the pressure in the adding expiration road in testing process as Rule of judgment; Eliminated under the flow velocity trigger condition continuous flow to the influence of expiration tidal volume; Make the error of expiration tidal volume to be controlled at effectively in 10%, simultaneously the more level and smooth technique effect of flow velocity waveform.

The above is merely the preferred embodiments of the present invention, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.All within spirit of the present invention and principle, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (10)

1. the detection method of the expiration tidal volume a when flow velocity that is used for respirator triggers is characterized in that, comprising:

When exhale action begins, detect second flow velocity of gas in the expiration pipeline of first flow velocity of gas in the aspirating air pipe of said respirator, said respirator and the force value in the said expiration pipeline simultaneously with predetermined time interval;

According to each detected said first flow velocity of the moment and said second flow velocity and said predetermined time interval, obtain respectively corresponding to said each expiration tidal volume constantly,

Wherein, each detected said force value is compared with scheduled pressure value, when said force value during less than said scheduled pressure value, this constantly and in expiratory phase subsequently the expiration tidal volume that obtains of the moment be set to 0; And

To the tidal volume of a plurality of said expiration tidal volumes summations with the expiration that obtains whole expiratory phase.

2. method according to claim 1 is characterized in that,

Through respectively each detected said second flow velocity of the moment and said first flow velocity being asked difference and the difference of said second flow velocity and said first flow velocity is carried out the integration acquisition corresponding to each expiration tidal volume constantly in said predetermined time intervals; And

When said force value during less than said scheduled pressure value, this constantly and in said expiratory phase subsequently constantly the difference of detected said second flow velocity and said first flow velocity be set to 0 and said expiration tidal volume is set to 0.

3. method according to claim 1 is characterized in that, said predetermined time interval is 10ms.

4. method according to claim 1 is characterized in that, said scheduled pressure value is 0.5 centimeter water column.

5. method according to claim 1 is characterized in that, detects said first flow velocity and said second flow velocity through flow sensor, detects said force value through pressure transducer.

6. an expiration tidal volume checkout gear is characterized in that, comprising:

Detection module; Be used for when exhale action begins; Detect second flow velocity of gas in first flow velocity, expiration pipeline of gas in the aspirating air pipe in the respirator and the force value in the said expiration pipeline with predetermined time interval simultaneously, and said first flow velocity and said second flow velocity in detected a plurality of moment is sent to processing module;

Said processing module; Be used for according to each detected said first flow velocity of the moment and said second flow velocity and said predetermined time interval; Obtain the expiration tidal volume in each predetermined time interval respectively; And be used for each detected said force value and scheduled pressure value are compared, when said force value during less than said scheduled pressure value, this constantly and in expiratory phase subsequently the expiration tidal volume that obtains of the moment be set to 0; And

Summation module is used to store by a plurality of said expiration tidal volume in a plurality of said predetermined time interval that obtains after the said processing module processing and to said a plurality of expiration tidal volumes and sues for peace to obtain the expiration tidal volume of whole expiratory phase.

7. device according to claim 6 is characterized in that, said processing module comprises:

Ask the differential mode piece, be used for respectively each detected said second flow velocity of the moment and said first flow velocity being asked poor;

Integration module is used for that the difference of said second flow velocity and said first flow velocity is carried out integration in said predetermined time interval and obtains corresponding to each expiration tidal volume constantly; And

Relatively reach module be set, be used in said force value during less than said scheduled pressure value, this constantly and in said expiratory phase subsequently constantly the difference of detected said second flow velocity and said first flow velocity be set to 0 and said expiration tidal volume is set to 0.

8. checkout gear according to claim 6 is characterized in that, said predetermined time interval is 10ms.

9. checkout gear according to claim 6 is characterized in that, said scheduled pressure value is 0.5 centimeter water column.

10. checkout gear according to claim 6 is characterized in that said detection module comprises flow sensor and pressure transducer.

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