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

• US 7,814,906 B2
• Filed: 05/05/2006
• Issued: 10/19/2010
• Est. Priority Date: 05/06/2005
• Status: Active Grant

• Current Assignee: Ginevri S.r.l.
• Original Assignee: Ginevri S.r.l.
• Inventors: Moretti, Corrado
• Primary Examiner(s): Yu; Justine R
• Assistant Examiner(s): Young; Rachel T
• Application Number:
  US11/418,196
• Publication Number:
  US 20060249156A1
• Time in Patent Office: 1,628 Days
• Field of Search: 12820024-20026, 128/204.18, 12820421-20423, 128/204.26, 12820429-20512, 128/207.16, 128/207.18
• US Class Current: 128/204.23
• 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. A method, for flow-synchronized neonatal assisted ventilation, wherein F(t) is a signal proportional to the ventilation flow, comprising the following steps:

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

(b) deactivating the electrovalve for expiration, for a time length Te, during which the introduction of air is interrupted; and

(c) returning to step (a);

during said expiration step (b) the following steps are provided;

(b1) a waiting step having a non-zero time length γ

before activation of computation of leakages in a ventilation circuit configured for a newborn; and

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

, so that γ

+δ

=Te, wherein when a normalized signal F′

(t), obtained by processing said detected signal F(t) according to a normalizing algorithm, exceeds an expiration flow rate threshold Ftr, a spontaneous respiration activity is determined and the step (a) is reactivated,

wherein said algorithm provides the following sub-steps;

sampling of the F(t) signal;

calculation of a 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),

wherein said variable average M(t) is calculated according to the following formula;

2. The method according to claim 1, wherein number N of said samples is 16.

3. The method according to claim 1, wherein 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 when F′

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

4. The method according to claim 1, wherein said time interval γ

is in the range between 0.20 and 0.25 seconds.

5. The method according to claim 4, wherein said time interval γ

is 0.20 seconds.

6. The method according to claim 3, wherein said time interval α

is included in the range between 0.20 and 0.25 seconds.

7. The method according to claim 3, wherein said time interval a is 0.20 seconds.

8. The method according to claim 3, wherein 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.

9. The method according to claim 1, wherein during step (b2), within time interval δ

it is possible to memorize the pressure at the end of expiration.

10. The method according to claim 1, wherein at the end of step (a), the maximum value of inspiration pressure is memorized.

11. The method according to claim 1, wherein said inspiration time interval is Ti.

12. The method according to claim 1, wherein said expiration time interval Te can be varied.

13. The method according to claim 1, wherein said Ftr threshold can be varied.

14. An apparatus for carrying out flow-synchronized neonatal assisted ventilation, said apparatus comprising:

interface means, suitable to adjust operation parameters by a user,

a circuit for nasal ventilation configured for a newborn,

a pneumotachograph connected to said circuit and connected to flow tubes and pressure detection tubes, said pneumotachograph is configured to detect a signal F(t) proportional to the ventilation flow rate and to detect a plurality of parameters, said plurality of parameters comprise inspiration time Ti, expiration time Te, expiration flow threshold Ftr and respiration frequency, wherein said circuit for nasal ventilation comprises a nose-cannula connected with said pneumotachograph,

an electrovalve connected with said circuit for nasal respiration for activating—

deactivating the introduction of air at an inspiration pressure through said circuit for nasal respiration, and

a processing and control unit, connected to said electrovalve and configured to control said electrovalve for activation during inspiration and deactivation during expiration, said deactivation including a waiting step having a non-zero time length γ

,

wherein the signal F(t) detected by the pneumotacograph is sampled,

wherein said processing and control unit is provided with processing means that activates said electrovalve for inspiration, for the time Ti, during which air is introduced at an inspiration pressure, deactivating said electrovalve for expiration, for the time Te, during which the introduction of air is interrupted,

wherein said processing means is configured to carry out the following electrovalve control;

waiting a time length g; and

computation of the leakages, having a time length d, so that g+d=Te, in which when a normalized signal F′

(t), obtained by processing said detected signal F(t), exceeds said expiration flow rate threshold Ftr, a spontaneous respiration activity is determined and the activation of the electrovalve for inspiration is reactivated,

said normalized signal F′

(t) being calculated for each sample for Ti+g<

t<

Ti<

Te, according to the formula F′

(t)=F(t)−

M(t) (for each t value), where M(t) is a variable average M(t), calculated according to the following formula;

15. The apparatus according to claim 14, further comprising memorisation means.

16. The apparatus according to claim 14, wherein, said interface means including a monitor.

17. The apparatus according to claim 14, wherein said interface means comprise a push-button panel.

18. The apparatus according to claim 14, wherein said interface means comprise a plurality of knobs.

19. The apparatus according to claim 14, wherein said interface means further comprise at least one of a plurality of optical warning devices and acoustic warning devices.

20. The apparatus according to claim 14, wherein said apparatus further comprise means for adjustment of respiration mixture.

21. An apparatus for nasal ventilation, for flow-synchronized neonatal assisted ventilation, comprising:

a circuit for nasal ventilation, configured to be applied to a newborn;

an electrovalve connected with said circuit for nasal ventilation, for activating—

deactivating the introduction of air at an inspiration pressure through said circuit for nasal ventilation;

a pneumotachograph, connected to flow tubes and pressure detection tubes, suitable to detect a signal F(t) proportional to the ventilation flow rate and a plurality of parameters, said parameters comprise inspiration time Ti, expiration time Te, expiration flow threshold Ftr and respiration frequency, said circuit for nasal ventilation comprises a nose-cannula connected with said pneumotachograph; and

a processing and control unit, connected to said electrovalve and said pneumotachograph, adapted to control said electrovalve, said processing and control unit being configured to;

(a) activate said electrovalve for inspiration, for a time length Ti, during which air is introduced at an inspiration pressure;

(b) deactivate said electrovalve for expiration, for a time length Te, during which the introduction of air is interrupted; and

then to return to activating said electrovalve for inspiration;

said (b) includes;

(b1) a wait having a time length γ

; and

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

, so that γ

+δ

=Te, in which when a normalized signal F′

(t), obtained by processing said detected signal F(t) according to a normalizing algorithm, exceeds an expiration flow rate threshold Ftr, a spontaneous respiration activity is determined and wherein said processing and control unit is provided with processing means that activate said electrovalve for inspiration, for the time Ti, during which air is introduced at an inspiration pressure, deactivating said electrovalve for expiration, for the time Te, during which the introduction of air is interrupted,

wherein said processing means carry out the following electrovalve control;

waiting a time length g; and

computation of the leakages, having a time length d, so that g+d=Te, in which when a normalized signal F′

(t), obtained by processing said detected signal F(t), exceeds said expiration flow rate threshold Ftr, a spontaneous respiration activity is determined and the activation of the electrovalve for inspiration is reactivated,

said normalized signal F′

(t) being calculated for each sample for Ti+g<

t<

Ti+Te, according to the formula F′

(t)=F(t)−

M(t) (for each t value), where M(t) is a variable average M(t), calculated according to the following formula;