Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Electrical energy applicator
Reexamination Certificate
1999-02-23
2004-09-07
Kamm, William E. (Department: 3762)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Electrical energy applicator
Reexamination Certificate
active
06786917
ABSTRACT:
The invention relates to a method and a device for producing a helper signal with the features of the preamble of the independent patent claims. Furthermore the invention relates to a flow measuring arrangement which is particularly suitable for the method according to the invention and the device according to the invention.
It is known with a cardiac arrest or with heart malfunctioning to apply electroshocks or cardiac massage. Defibrillators (for producing electroshocks) or cardiac massages are often used in first aid activity. Electrical stimulations may however also be carried out via external pacemakers.
It is important to know at which point in time and whether a defibrillation or a cardiac massage must be carried out. With a tachycardia or rhythm malfunctioning defibrillations may also be carried out when a pulse is ascertained, but is irregular or too fast. Generally, a defibrillation should only be carried out, when with the patient a pulse can no longer be ascertained. Normally with this the (carotid) pulse of the patient is manually felt. With this above all with a weak pulse a superposition of the pulse of the patient with the pulse of the helper may arise.
Furthermore it is important to determine the necessity of a defibrillation or of a cardiac massage as well as the point in time at which the reanimation may be stopped.
It is further known to check the course of a reanimation with an electrocardiogram.
Such a checking of the reanimation however has various disadvantages. The blood circulation of the head must be recreated within three minutes of cardiac arrest in order to avoid irreparable brain damage. Although during a reanimation a heart beat may already set in and lead to a corresponding ECG signal, however the blood circulation of the brain is not yet sufficient to permit the halt of the reanimation.
On account of the ECG signal alone it is furthermore difficult to determine the necessity for activating the defibrillation current or cardiac massage. For this reason during the reanimation the pulse of the patient is manually measured. A defibrillation is not only activated with a loss of pulse.
Defibrillation may be required in varying situations. With so-called ventricular fibrillation (i.e. with irregular electrical action potentials with a frequency band width of 0 to approx. 15 Hz) the fibrillation may be ended by defibrillation. After the defibrillation has been effected the heart again finds its own rhythm. The pump output with ventricular fibrillation is practically equal to zero.
With so-called tachycardia the pulse beat with a heart which is not strained is very high. The beat volume with this is considerably reduced. Tachycardia may lead to ventricular palpitation which in turn leads to ventricular fibrillation.
In both cases a defibrillation is only carried out as soon as a pulse can no longer be felt. As soon as the pulse can be felt, synchronously a defibrillation with a low energy step (cardioversion) may be carried out.
With ventricular fibrillation the delivery of shock is effected a synchronously to the ECG, with cardioversion the delivery of shock is effected synchronously to the R-zag of the ECG.
With all applications of defibrillation the mechanical activity of the heart is acquired. Since often in the extremities of the patient a hypoxaemia prevails, the carotid pulse at the carotid artery is measured.
Above all with cardiac pressure massage the mechanical condition of the heart is important. The pressure point and the massage frequency should be determined in dependence on the measured pumping volume and where appropriate be changed, i.e. optimised.
It is the object of the present invention to avoid the disadvantages of that which is known, thus in particular to provide a method and a device for producing a helper signal as an aid to the decision for the activation of a defibrillation and/or a cardiac massage with heart malfunctioning, which ensures that the reanimation is only ended after reaching an adequate circulation of the brain. Furthermore the necessity to activate the individual defibrillation current shocks or cardiac massage is to be able to be determined with the method according to the invention and with the device according to the invention.
According to the invention these objects are achieved with a method and a device with the features of the characterising part of the independent patent claims.
In a method for producing a helper signal for determining the point in time for the actuation of a defibrillation and/or a cardiac massage with heart malfunctioning of a mammal, in particular of a human, the flow or the speed of the blood in the carotid artery is measured and a helper signal is activated dependent on the value of the speed of the blood flow into the head of the mammal and where appropriate dependent on an ECG signal. With this the basic concept of the invention lies in the fact that the pulse, in particular the blood flow into the head is automatically measured and displayed in the form of a helper signal. The helper signal may be used for determining the necessity of a treatment, for optimising the treatment or for monitoring. The helper signal aids the treating person.
In this context heart malfunctioning is to be understood as a momentary cardiac arrest as well as also an insufficient or irregular heart beat. Here and in the following a heart beat is to be understood as the contraction of the cardiac muscle.
The activation of electroshocks for the reanimation of the heart (defibrillation) and the drawing up of electrocardiograms during the reanimation is already known as such and is not the subject-matter of the present invention.
Principally the method according to the invention may be used with a defibrillation as well as with a cardiac massage.
Because the helper signal is actuated in dependence on the value of the blood flow it is guaranteed that the reanimation is continued for so long until an adequate blood circulation of the brain is ensured. In combination with an ECG also the necessity of a defibrillation may be judged much better. Furthermore the dependence of the helper signal on the value of the blood flow leads to the fact that the helper signal may be produced synchronously with the heart beat. Above all with cardiac massage the helper signal permits a feedback. In dependence on the signal the pressure point for the massage may be optimised. The helper signal furthermore also lends itself to monitoring.
In this context blood flow is to be understood as the volume of blood which flows from the heart into the head part per certain unit of time. The flow of blood may be measured most simply at the carotid artery.
Thanks to the helper signal an ambulance man may follow the pulse in the carotid artery without having to manually measure. In a further developed embodiment example the value of the blood flow is compared to a predeterminable nominal value. As long as at least the value of the amplitude of the blood flow lies below the corresponding nominal value, the helper signal is actuated. As soon as a heart beat can be recognised the helper signal is preferably activated at the point in time of the heart beat (i.e. at maximum flow) as long as the value of the maximum flow lies below the nominal value. The comparison arrangement computes, proceeding from the signals, the necessity and where appropriate the point in time for carrying out a reanimation.
As soon as a heart beat sets in after cardiac arrest, the helper signal may be used for monitoring the efficiency of the heart activity.
As a helper signal basically any signal is conceivable which displays to the person doing the treating the blood flow or the heart beat for activating the defibrillation and/or the cardiac massage. Acoustic or optical signals can be particularly simply realised and are effective. As an optical signal for example a flow curve indicated on a monitor but also a signal lamp are conceivable.
The helper signal may continuously display the value of the flow as a time-dependent curve. It is however also conceivable to produc
Schiller Alfred
Stemple Günter
Kamm William E.
Shoemaker and Mattare Ltd.
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