Surgery – Respiratory method or device – Means for supplying respiratory gas under positive pressure
Reexamination Certificate
2000-10-18
2003-05-06
Lo, Weilun (Department: 3761)
Surgery
Respiratory method or device
Means for supplying respiratory gas under positive pressure
C128S204210
Reexamination Certificate
active
06557554
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an artificial respiration apparatus and in particular, to a high-frequency oscillation respiration apparatus.
2. Description of the Related Art
As shown in
FIG. 16
, in a conventional high-frequency oscillation aspiration apparatus
200
, an inhale gas containing a high-concentration oxygen is supplied from an oxygen supply source
201
to flow through a fluid path system having a three-way branching pipe
202
for branching to a patient X and an exhale side. The inhale gas is urged by a high-frequency (3 to 15 Hz) oscillating air pressure generated by an oscillating air pressure urging unit
203
to flow with a flow rate of 10 to 30 [1/min] at a normal mode and 60 [1/min] at maximum for supplying oxygen to lungs of the patient X. Here, the average pressure applied to the lungs of the patient is controlled according to an open degree of a rubber valve of an inhale valve
204
provided at an outlet of the inhale gas. The average pressure is normally set so as to maintain 5 to 15 [cm H
2
O] (490 to 1470 [Pa]) (hereinafter, the pressure values represent values added to the atmospheric pressure).
Explanation will be given on a principle of oxygen supply in the high-frequency oscillation artificial respiration apparatus
200
. Firstly, when an inhale gas to be supplied to a patient is urged by a high-frequency oscillation oscillating air pressure, the pressure amplitude of the inhale gas causes a small-amount ventilation (gas exchange like convection) with respect to the gas containing carbon dioxide to be exhaled (hereinafter, referred to as an exhale gas). Simultaneously with this, vibration of the inhale gas causes a diffusion movement, which causes the inhale gas to intrude into the lungs via an in-trachea tube
207
and the exhale gas to be transferred out of the lungs (up to the mouth of the patient). A subsequent exhale gas portion performs the aforementioned ventilation and urges the exhale gas, which has been transferred out of the lungs, to be sent to the outlet. Thus, it is possible to maintain a constant oxygen concentration in the lungs of the patient.
Japanese Utility Model Publication (examined) 2-7569 discloses a high-frequency oscillation artificial respiration apparatus using a mechanical piston and electrical speaker vibration as an oscillating air pressure urging unit. However, these methods provide only a small amplitude of oscillating air pressure for urging the inhale gas and cannot perform a sufficient ventilation for lungs of a grow-up and have been used only for new-born babies.
In the high-frequency oscillation artificial respiration apparatus as shown in
FIG. 16
, which is disclosed in Japanese Patent Nos. 2798255, 2798256, and 2798257, a blower
205
and a rotary valve
206
are used as the oscillating air pressure urging unit
203
so as to improve the high-frequency oscillation oscillation.
Moreover, in the aforementioned high-frequency oscillation artificial respiration apparatus
200
, the user (doctor) can set the following basic parameters according to the state of the patient: (1) inner pressure (5 to 15 [cmH
2
O] (490 to 1470 [Pa]) of a flow path from the oxygen supply source to the patient x; (2) a ventilation amount per oscillation cycle with respect to the lungs of the patient (hereinafter, referred to as one ventilation amount against the lungs of the patient; more specifically, several to several hundreds of [ml] according to the weight of the patient); and (3) ventilation frequency (3 to 15 [Hz]) of the oscillating air pressure. In addition to these, there are accompanying parameters: an inhale gas supply amount and an inhale gas oxygen concentration of the inhale gas sent to the patient. According to the state of the patient, the aforementioned basic parameters are controlled as follows to control respiration.
(1) When oxidation is required, i.e., when it is necessary to increase the partial pressure of oxygen (PaO
2
) in the artery blood of the patient X, the average inner pressure in the flow path up to the patient is increased.
(2) When it is necessary to quickly exhaust carbon dioxide, i.e., when it is necessary to lower the partial pressure of carbon dioxide (PaO
2
) in the artery blood, one ventilation amount against the lungs of the patient is increased.
(3) The inherent frequency increasing the ventilation efficiency varies depending of each of the patients X as well as the state of the patient. The ventilation frequency is regulated so that the frequency is near the inherent frequency.
The ventilation frequency, at the initial stage, is determined according to the weight of the patient, and then adjusted to a frequency at which resonance is generated with the body of the patient X to increase the gas (oxygen) diffusion efficiency and the gas exchange (between oxygen and carbon dioxide) is effectively performed. In general, the ventilation frequency is set to about 15 {Hz] for a new-born baby and 3 to 10 {Hz] for a child or a grown-up.
During an artificial respiration, the ventilation frequency is normally fixed unless a sudden change is caused in the state of the patient X. The ventilation frequency is not often changed. Accordingly, normally, in order to perform a desired artificial respiration according to the state of the patient X, the respiration state is adjusted with the parameter (1) or (2).
In the aforementioned conventional high-frequency oscillation artificial respiration apparatus
200
, the oscillating air pressure amplitude is increased by using a blower
205
having a large output, thus enabling to obtain a sufficient ventilation for lungs of a grown-up.
FIG. 17
graphically shows an inner pressure change in the vicinity of the three-way branching pipe
202
during a high-frequency oscillation artificial respiration.
However, in the oscillating air pressure urging unit
203
of the aforementioned conventional high-frequency oscillation artificial respiration apparatus
200
, the inner pressure amplitude (difference between the uppermost pressure and the lowermost pressure) in the vicinity of the three-way branching pipe
202
during a high-frequency oscillation artificial respiration exceeds 100 [cm H
2
O] (9800 [Pa]) and accordingly, it is necessary to carefully adjust the pressure for a patient.
The pressure applied to lungs of a human being is a load to the lungs if the pressure is too high or too low. In the conventional example, the pressure amplitude is increased to perform a sufficient ventilation, which means that the pressure approaches the uppermost or the lowermost pressure. In order to perform a high-frequency oscillation artificial respiration without applying a load to the lungs of a patient, it is necessary to set the pressure with a great care.
Moreover, in the aforementioned high-frequency oscillation artificial respiration apparatus
200
, even when the pressure is in a range not applying a load to a patient, a high-frequency oscillation artificial respiration with a large pressure amplitude causes a large vibration of the breast of the patient X, which is not preferable when a medical instrument of instillation or a catheter is applied to the patient X or when a measurement is to be performed using a measurement apparatus.
Furthermore, when the pressure amplitude is increased in the high-frequency oscillation artificial respiration apparatus
200
, there arises a problem that the oscillating air pressure urging unit
203
causes a large noise and the power consumption is also increased.
Moreover, there is a case that the patient state is suddenly changed, resulting in an excessive decrease or increase of PaO
2
. In such a case, the inherent frequency of the patient X has been changed and the adjustments of (1) and (2) alone are insufficient. The ventilation frequency should be changed.
However, when the ventilation frequency is changed, the oscillating flow state in the in-trachea tube is
Greenblum & Bernstein P.L.C.
Lo Weilun
Patel Mital
Suzuki Motor Corporation
LandOfFree
High-frequency oscillation artificial respiration apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with High-frequency oscillation artificial respiration apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High-frequency oscillation artificial respiration apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3057793