Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Electrical therapeutic systems
Reexamination Certificate
2001-03-20
2003-06-17
Jeffery, John A. (Department: 3742)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Electrical therapeutic systems
Reexamination Certificate
active
06580945
ABSTRACT:
BACKGROUND OF THE INVENTION
Description of the Related Art
A cardiac arrest is a disruption of the heart's functioning that causes a lack of blood flow to vital organs. The majority of cardiac arrests are associated with a heart arrhythmia such as ventricular fibrillation. During ventricular fibrillation, the normal rhythmic ventricular contractions are replaced by rapid and irregular twitching that results in ineffective and severely reduced pumping of the heart. One method of treating ventricular fibrillation is to use a defibrillator to administer shocks to a patient's heart in order to restore the normal rhythmic ventricular contractions.
There are multiple types of defibrillators, each used for different purposes. Internal defibrillators are implanted in the patient and are used to prevent ventricular fibrillation and regulate the heart rhythms. External defibrillators are used by paramedics and hospitals in order to treat ventricular fibrillation after the occurrence of a heart attack. External defibrillators often have numerous additional features, such as smaller ECG units, that aid in treating the patient and evaluating the factors used in administering shocks. The external defibrillators can be fully automatic, semi-automatic, or manual, depending on the end operator. The more automatic a defibrillator, the greater the role of a controller within the defibrillator plays in administering treatment.
These defibrillators can be portable, such as those used by paramedics and EMS personnel, or attached to carts such as those found in clinics and hospitals. One such portable external defibrillator is disclosed in U.S. Pat. No. 6,141,584 to Rockwell et al., which is commonly assigned and the disclosure of which is incorporated herein by reference.
As shown in
FIG. 1
, a defibrillator system
1
includes a defibrillator
10
which administers a shock to the patient through paddles/electrodes
20
. As shown in
FIG. 2
, the paddles
20
are connected to a connector
22
by leads
30
. The connector
22
is inserted into socket
14
in order to deliver the charge from the defibrillator
10
to the paddles
20
. In order to direct the defibrillator
10
to administer the shock, the operator presses a shock button
12
that is located on the defibrillator
10
.
In addition, the defibrillator
10
also has a display
16
that is used by the operator to view ECG information or other information useful in the caring for and monitoring of the progress of the patient. The ECG information, which provides information on the condition of the patient's heart, is received through the paddles
20
that also provide the shock to the patient. Since the shown the defibrillator
10
is portable, it has a battery charge indicator
18
so that the operator can assess the ability of the defibrillator
10
to continue to administer treatment to the patient.
In operation, when a patient goes into cardiac arrest, the electrodes
20
are applied across the chest of the patient in order to acquire the ECG signal from the patient's heart. The ECG information is displayed to the operator on the display
16
. In a manual defibrillator, the operator determines from the ECG information whether to administer the shock. For automatic and semiautomatic defibrillators, the defibrillator
10
aids in this determination to varying degrees.
However determined, if ventricular fibrillation is to be treated with the defibrillator system
1
, the operator applies the paddles
20
to the patient and presses the shock button
12
. The defibrillator administers the shock through the paddles
20
to the patient in order to restore the normal rhythm of the heart. The defibrillator
10
is then used to again assess the condition of the patient, and to administer further treatments based on the detected ECG signal. In general, only three such treatments are provided with any likelihood of success.
FIG. 3
is a schematic representation of the defibrillator
10
. The paddles
20
provide an ECG signal to the ECG front end
102
, which provides the ECG signal to a controller
106
for evaluation and display to the operator via a user interface
114
. This information is also stored by the controller
106
in a memory
118
. Also stored in the memory
118
is an event summary
130
, in which information from an event mark
110
, a microphone
112
, and/or from a clock
116
are stored. This information is useful during a transfer (often called a handoff) between the hospital and the clinic in order to continue the treatment of the patient. In the device shown, an infrared communications port
120
is provided to communicate the information in memory
118
with an outside device during the transfer.
In addition, a power source
140
is provided in order to power the entire defibrillator
10
. The power source
140
can be a line source or a battery, or any similar device which provides sufficient power to provide the shock and the ECG monitoring functions described herein. For portable defibrillators such as that shown, a battery is typically used for the power source
140
. This battery may be disposable, or rechargeable.
A high voltage (HV) delivery device
108
administers the shock to the patient via the paddles
20
at the command of the controller
106
. At the command of the operator using the shock button
12
, the charge from the high voltage delivery device
108
is administered to the patient in order to bring about the normal rhythmic ventricular contractions. The power supply
140
supplies the charging energy to the high voltage delivery device
108
during a charging time in order to store sufficient energy to administer a treatment. This charging time is preferably small since the rapid administration of the treatments is desirable in order to produce a favorable result.
As schematically shown in
FIG. 4
, the high voltage delivery device
108
has two major components: a transformer
204
and a high voltage capacitor
206
(i.e., “HV cap”). When in operation, the power source
140
provides power through the transformer
204
to charge the HV cap
206
. The HV cap
206
stores the required voltage to be administered on the command of the operator or a controller
106
shown in FIG.
3
. The HV cap
206
is typically a 105 &mgr;f capacitor, and is capable of delivering a charge of 2100 volts to the patient through terminals
208
to the paddles
20
shown in FIG.
3
. After discharge, the HV cap
206
is then recharged by the power source
140
if there is a continued need for defibrillation treatment.
A second type of defibrillator is an internal defibrillator. Internal defibrillators use a similar process for charging an HV cap. As shown in
FIG. 5
, an internal defibrillator
300
uses a power source
310
to charge a high voltage delivery device
320
, which is a similar structure to the high voltage delivery device
108
shown in FIG.
4
. The controller
330
controls the discharge of the high voltage delivery device
320
through the heart in order to regulate the rhythm of the heart. Where multiple capacitors are used in the high voltage delivery device
320
, the high voltage delivery device
320
further includes an H-bridge in order to selectively provide shocks from the individual capacitors to the patient. In addition, the power source
310
is often a battery. An example of one such known internal defibrillator is found in U.S. Pat. No. 6,035,235 to Perttu et al.
A drawback to the conventional defibrillator designs, both external and internal, is the need for larger power sources to charge the HV cap in order to provide the necessary shock. For certain external defibrillators, especially those used in clinics, a line voltage can be supplied instead of a battery. However, such line sources limit the portability of these defibrillators when used in confined spaces.
A further problem encountered during the use of a defibrillator device is how to discharge or otherwise dissipate energy from the high voltage delivery device when the stored energy is not to be applied to a patient. A
Langguth Al
Mulhauser Daniel F.
Jeffery John A.
Koninklijke Philips Electronics , N.V.
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