Method and relevant apparatus for nasal ventilation, particularly for flow-synchronised neonatal assisted ventilation

• US 20060249156A1
• Filed: 05/05/2006
• Published: 11/09/2006
• Est. Priority Date: 05/06/2005
• Status: Active Grant

• Current Assignee: Ginevri S.r.l.
• Original Assignee: Ginevri S.r.l.
• Inventors: Moretti, Corrado
• Granted Patent: US 7,814,906 B2
• Time in Patent Office: Days
• US Class Current: 128/204.230
• CPC Class Codes: A61M 16/0666 Nasal cannulas or tubing devices for improving normal breathing through the nose A61F5/08; nose filters A62B23/06; outside holding devices A61M25/02
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2240/00 Specially adapted for neonatal use

Abstract

In a method for nasal ventilation and relevant apparatus, particularly for flow-synchronized neonatal assisted ventilation, wherein F(t) is a signal proportional to the ventilation flow, the following steps are performed: (a) inspiration, having a time length Ti, during which air is introduced at an inspiration pressure; (b) expiration, having a time length Te, during which the introduction of air is interrupted; (c) return to step (a); with a flow threshold Ftr, during the expiration step (b) the following steps are provided: (b1) a waiting step having a time length γ before activation of computation of the leakages; and (b2) a step of leakage computation, having a time length δ, so that γ+δ=Te, wherein if a normalized signal F′ (t), obtained by a processing by way of an algorithm of the surveyed signal F(t), exceeds the threshold Ftr, a spontaneous respiration activity is detected and the inspiration step (a) is reactivated.

Claims

1. Method for nasal ventilation and relevant apparatus, particularly for flow-synchronized neonatal assisted ventilation, wherein F(t) is a signal proportional to the ventilation flow, comprising the following steps:

(a) inspiration, having a time length Ti, during which air is introduced at an inspiration pressure;

(b) expiration, having a time length Te, during which the introduction of air is interrupted;

(c) return to step (a);

characterised in that it comprises a flow threshold Ftr, and in that during said expiration step (b) the following steps are provided;

(b1) a waiting step having a time length γ

before the activation of the computation of the leakages; and

(b2) a step of computation of the leakages, having a time length δ

, so that γ

+δ

=Te, wherein if a normalized signal F′

(t), obtained by a processing by means of an algorithm of the surveyed signal F(t), exceeds the threshold Ftr, a spontaneous respiration activity is detected and the inspiration step (a) is reactivated.

2. Method according to claim 1, characterised in that said algorithm provides the following sub-steps:

sampling of the F(t) signal;

calculation of the variable average M(t) for each sample for Ti+γ

<

t<

Ti+Te;

calculation of F′

(t) signal according to formula F′

(t)=F(t)−

M(t) (for each t value).

3. Method according to claim 2, characterised in that said variable average M(t) is calculated according to the following formula:

$M<br><br>\left(t\right)=\frac{\underset{i=1}{\overset{N}{\sum <br><br>}}<br><br>F_i<br><br>\left(t\right)}{N}$ $\mathrm{per}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{Ti}+\mathrm{\gamma <br><br>}<<br><br>t<<br><br>\mathrm{Ti}+\mathrm{Te},$

wherein i is the index numbering F(t) samples;

N is the number of samples used for calculation of leakages (b2).

4. Method according to claim 3, characterised in that calculation of average is carried out for each sample acquired during step (b2), inserting each time the new value acquired.

5. Method according to claim 3, characterised in that number N of said samples is 16.

6. Method according to claim 1, characterised in that step (b2) is divided into two further steps, during respectively α

and β

, so that γ

=α

+β

;

a first further waiting step;

a second step for verifying presence of spontaneous activity, wherein if F′

(t) passes threshold Ftr, inspiration step (a) is reactivated.

7. Method according to claim 1, characterised in that said time interval γ

in included in the range between 0.20 and 0.25 seconds.

8. Method according to claim 7, characterised in that said time interval γ

is of 0.20 seconds.

9. Method according to claim 6, characterised in that said time interval α

is included in the range between 0.20 and 0.25 seconds.

10. Method according to claim 6, characterised in that said time interval α

is of 0.20 seconds.

11. Method according to claim 6, characterised in that in said method, during step b(2), if signal F′

(t) takes value Ftr (with Ti+γ

+α

<

t<

Ti+γ

+δ

), inspiration step (a) can be reactivated.

12. Method according to claim 1, characterised in that during step (b2), within time interval δ

it is possible memorising pressure at the end of expiration.

13. Method according to claim 1, characterised in that at the end of step (a) it is memorised the maximum value of inspiration pressure.

14. Method according to claim 1, characterised in that said inspiration time interval Ti.

15. Method according to claim 1, characterised in that said expiration time interval Te can be varied.

16. Method according to claim 1, characterised in that said Ftr threshold can be varied.

17. Apparatus for carrying out method according claim 1, characterised in that it comprises a processing and control unit, interface means, suitable to adjust operation parameters by a user, a circuit for nasal ventilation and an electrovalve for activation—

deactivation of the inspiration step, said electrovalve being connected with said circuit for nasal respiration.

18. Method according to claim 14, characterised in that said nasal ventilation circuit comprises a nose-cannula connected with a pneumotachograph, to which flow tubes and pressure detection tubes are connected.

19. Method according to claim 16, characterised in that said apparatus comprises memorisation means and/or interface means.

20. Method according to claim 17, characterised in that, said interface means including a monitor.

21. Method according to claim 17, characterised in that said interface means comprise a push-button panel.

22. Method according to claim 17, characterised in that said interface means comprise a plurality of knobs.

23. Method according to claim 17, characterised in that said interface means comprise a plurality of optical and/or acoustic warning devices.

24. Method according to claim 17, characterised in that said parameters comprise inspiration time Ti, expiration time Te, expiration flow threshold Ftr, respiration frequency.

25. Method according to claim 17, characterised in that said apparatus comprise means for adjustment of respiration mixture.

26. Method ad apparatus according to each claim 1, substantially as illustrated and described.