WO2008023304A2

WO2008023304A2 - Administration of medicaments for cardiac resuscitation

Info

Publication number: WO2008023304A2
Application number: PCT/IB2007/053238
Authority: WO
Inventors: Giovanni Nisato; Shervin Ayati; Michael Perkuhn
Original assignee: Koninklijke Philips Electronics, N.V.
Priority date: 2006-08-21
Filing date: 2007-08-14
Publication date: 2008-02-28
Also published as: CN101505829A; JP2010501239A; WO2008023304A3; EP2056932A2

Abstract

An external defibrillator and method are described which enable a rescuer to administer epinephrine to a patient through transdermal injection controlled by the defibrillator. In one example a medicament injector is embedded in a defibrillation electrode. If attempts to resuscitate the patient through defibrillation are unsuccessful, the medicament injector is triggered from the controls of the defibrillator to cause the embedded injector to inject epinephrine into the skin of the patient. The injector may alternatively be attached to and controlled from the defibrillator independent of the defibrillation electrodes.

Description

ADMINISTRATION OF MEDICAMENTS FOR CARDIAC RESUSCITATION

This invention relates to cardiac resuscitation and, in particular, to the administration of medicaments such as epinephrine to patients experiencing cardiac arrest.

Cardiac arrest is a critical medical emergency. Following cardiac arrest oxygen can no longer be delivered to tissues, normal metabolism can no longer take place and irreversible damage (most notably to the heart itself and to the brain) rapidly occurs. After cardiac arrest oxygen pressure decreases rapidly in the brain (partial O₂ pressure decays from 13 kPa to < 3 kPa within 15 seconds) and consciousness is lost. Tissue damage is caused by metabolic changes brought about by the insufficient oxygen influx. Carbon dioxide is progressively accumulated and oxygen-haemoglobin dissociation rates are modified. In the case of ventricular fibrillation, anaerobic metabolism increases leading to acidosis, threatening brain damage in 5-6 minutes. Unless rapidly and correctly treated, cardiac arrest is fatal. Many cardiac arrests caused by ventricular fibrillation can be reversed using appropriate electrical defibrillation, but the chances of recovery decrease 2-7% for every minute after cardiac arrest. Defibrillation is induced by delivering large electrical currents through the myocardium. The current simultaneously depolarizes a critical mass of the heart and induces a refractory period, preventing for a short time the propagation of chaotic, uncoordinated electrical stimuli occurring during the arrhythmia. The sino-atrial pacemaker cells, the earliest myocardial cells to spontaneously depolarize, then have a chance then re-establish a normal sinusoidal rhythm. Pulseless electrical activity and asystolic conditions also require CPR and infusion of pharmaceutical compounds for resolution .

Defibrillators deliver a high-voltage impulse to the heart in order to restore the normal rhythm and contractile function in patients who are experiencing arrhythmia, such as ventricular fibrillation, also referred to as sudden cardiac arrest, or ventricular tachycardia. There are several classes of defibrillators, including manual defibrillators, implantable defibrillators, and automatic external defibrillators (AEDs) . AEDs differ from manual defibrillators in that AEDs are pre-programmed to automatically analyze the electrocardiogram ("ECG") rhythm to determine if defibrillation is necessary and to provide administration measures such as shock sequences of the appropriate energy level followed or succeeded by periods when CPR is administered to the patient. AEDs are thus suitable for use by rescuers with no extensive medical training. Manual defibrillators are used by clinicians trained and experienced in advanced cardiac life support (ACLS) who are capable of reading a patient's ECG waveform, determining whether a shock is appropriate, then setting up the defibrillator to deliver the proper shock sequence and energy level. FIG. 1 is an illustration of a defibrillator 100 being applied by a rescuer 112 to resuscitate a patient 114 suffering from cardiac arrest. In sudden cardiac arrest, the patient is stricken with a life threatening interruption to the normal heart rhythm, typically in the form of ventricular fibrillation or ventricular tachycardia that is not accompanied by a palpable pulse (i.e., shockable ventricular tachycardia) . In ventricular fibrillation, the normal rhythmic ventricular contractions are replaced by rapid, irregular twitching that results in ineffective and severely reduced pumping by the heart. In the use of the defibrillator 100 a pair of electrodes 116 are applied across the chest of the patient 114 by the rescuer 12 in order to acquire an ECG signal from the patient's heart. The rescuer 112 then analyzes the ECG signal for signs of arrhythmia. If a treatable arrhythmia is detected, the user presses a shock button on the defibrillator 100 to deliver defibrillation pulses to resuscitate the patient 14. A typical defibrillation protocol may deliver several series of shocks, each pulse in the series delivering an increased amount of energy. If the patient has not been resuscitated following the shock sequences and intervening periods of CPR, the rescuer may consider other forms of treatment including drug therapy.

While awaiting the arrival of specially trained medical personnel for expert treatment of an unresuscitated patient it is desirable provide any aid that will improve the chance of recover for, as previously mentioned, time without oxygenated blood flow is the greatest impediment to survival. One possible treatment following unsuccessful resuscitation is drug therapy. The primary drug used at the present time in these situations is epinephrine. This compound has the ability to increase blood flow to the heart and brain by restricting peripheral vascular flow through increased resistance to flow in the peripheral vasculature. However layperson rescuers usually lack the training to safely and effectively administer intravenous injections, and providing needles along with an AED suitable for use by minimally trained rescuers would complicate an already stressful situation and could lead to improper or untimely drug administration. Accordingly it is desirable to facilitate drug treatment in concert with electrical defibrillation in a manner which is safe and effective for use by both layperson rescuers and trained emergency personnel.

In accordance with the principles of the present invention, an external defibrillator is provided which is coupled to a medicament dispensing system. The defibrillator unit triggers the drug injection in the event the defibrillation procedure has failed to resuscitate the patient. To insure safety, ease of use and speed, the dispensing system is preferably a needle-less injection system. Examples of needle- free injectors include piezoelectric actuators, spring loaded or compressed gas units. The injection system in an example shown below is housed in an electrode or similar pad attached to the patient and is controlled from the defibrillator unit. In the drawings: FIG. 1 is an illustration of a defibrillator being applied to a patient suffering from cardiac arrest .

FIG. 2 illustrates in block diagram form an external defibrillator controlling a medicament injector in accordance with the principles of the present invention.

FIG. 3 illustrates the constituent parts of a medicament injector constructed in accordance with the principles of the present invention. FIG. 4 is an illustration of a medicament injector powered by compressed gas.

FIG. 5 is an illustration of a medicament injector with a piezoelectric driver.

FIG. 6 is an illustration of a medicament injector with a piezoelectric jet injector.

FIGS. 7 is a detailed drawing of the piezoelectric injector mechanism of FIG. 6.

FIG. 8 illustrates the incorporation of a medicament injector into a patient electrode in accordance with the principles of the present invention .

FIG. 9 is a perspective view of a pair of electrode pads constructed in accordance with the present invention. FIG. 10 is a cross sectional view of an electrode pad of FIG. 9 including a medicament injector .

FIG. 11a is a cross sectional view of another electrode pad of the present invention with a medicament inspection window.

FIG. lib shows a medicament injector with an automatic monitor for the medicament reservoir.

Referring to FIGURE 2, a patient monitor/ defibrillator constructed in accordance with the principles of the present invention is shown in block diagram form. The instrument shown in FIGURE 1 is capable of performing defibrillation of a patient who is experiencing ventricular fibrillation. It is also capable of performing ECG monitoring including the cardiac monitoring and ECG waveform analysis necessary for automatic defibrillation decision- making. The illustrated monitor is also capable of SpO₂ oxygen sensing, noninvasive blood pressure monitoring, and end tidal CO₂ monitoring. Other functions such as invasive blood pressure monitoring and patient temperature monitoring may also be found in such a multi-functional instrument. The monitor has a plurality of patient front-ends, which are input circuitry for the sensors attached to the patient. This circuitry includes conventional sensing and amplification circuitry for ECG electrodes, for optical oxygen sensors, for pressure sensing and for carbon dioxide sensing, among others. In this example this circuitry includes connections for defibrillator electrodes. The information received by the patient sensors and processed by the front-end circuitry 10 is digitized by front-end A/D converters 12. The digitized information is coupled to processing circuitry of the instrument by a communications bus 60 which connects data between the various modules of the instrument.

The instrument of FIGURE 2 includes high voltage circuitry 16 for defibrillator operation. The high voltage circuitry produces the high voltage pulse necessary for defibrillation which is connected at the appropriate time by switching logic 14 to defibrillator electrodes coupled to the patient. This circuitry provides the high voltage shock needed to disrupt the ventricular fibrillation and returns the heart to a normal rhythm. The shock level and waveform delivered for defibrillation can be automatically calculated by a processor in the monitor or can be manually set by an experienced medical technician or physician. Power for the modules within the instrument is distributed by power handling circuits 20. The power handling circuits 20 will distribute power from batteries 22, from an AC supply 24, or from a DC supply 26. The AC and DC supplies are also coupled to circuitry which charges the batteries when the monitor is powered from these external power sources.

The instrument of FIGURE 2 is operated and adjusted by means of a keypad and controls 32. In a constructed implementation the keypad is a membrane keypad providing integrity against environmental conditions. Controls such as an on/off switch, power level and shock delivery controls for defibrillation, a printer, and other functions may also be provided. The defibrillator/monitor is operated under control of a central processing unit (CPU) 40. The CPU runs software stored on a read-only memory (ROM) 38. Flash ROM is also provided for the control of feature setups and new or special capabilities such as waveform information. Removable memory 36 is provided for storage of information generated during a patient episode such a ventricular fibrillation. Patient information such as cardiac waveforms before and after defibrillation are also stored on the removable memory 36, which can be removed and given to a subsequent care-giver for review, record- keeping, and subsequent diagnosis. The removable memory 36 can also record voice information from a care-giver speaking into a microphone 48. The information obtained by the instrument may be sent to other instruments or locations by communications circuitry 30. This may include a network connection, an RS232 connection, or a wireless connection (e.g. Bluetooth, WiFi or infrared, etc.)

Beepers 34 are used to drive a solid-state sound source that produces short "chirping" sounds. These sounds indicate that the instrument's resident self- test has detected a low battery level or a malfunction in a patient-critical circuit group. There is also a dedicated display on the front of the instrument that presents a large, flashing, red X to indicate a low battery level or a large, fixed, red X to identify a circuit failure. The display is also used to signal events such as defibrillation or epinephrine injection as discussed below. The display can also signal the need to replace an epinephrine cartridge or pad set due to an expiration date, excessive storage temperature or instability of the drug solution as described below.

Tones 46 are produced by the software and then used to drive the speaker 42. This capability is used during certain monitoring functions such as a short tone in response to each heart cycle. Combinations of tones are used to issue audible alerts and alarms when a patient's vital measurements fall outside the alarm limits selected. The speaker 42 can reproduce pre-recorded voice instructions (prompts) and information stored and reproduced from voice out circuitry 44. The speaker can also announce the completion of an epinephrine injection. A display 50 is provided for the display of patient parameters and waveforms and other instrument and patient related information. The information to be displayed is provided to a display controller 52 which provides the necessary drive signals for display of the information on the display. In a constructed implementation the display is a color LCD display, although other types of display such as a CRT display may be used in a particular implementation . In accordance with the principles of the present invention a medicament injector 54 is coupled to and controlled by the defibrillator/monitor . As explained more fully below the injector may be applied to the patient independent of any other instrument device or sensor. The injector 54 may alternatively be combined with another device or sensor such as being embedded in a defibrillator electrode pad applied to the patient. Preferably the medicament injector 54 is needle-free so as not to pose a hazard to an untrained rescuer. The injector is coupled to the defibrillator/monitor by a control line through which control signals are applied to trigger the administration of injections. FIGURE 3 provides a simple example of a medicament injector 54 of the present invention. A nozzle 72 emits the drug or medication under pressure to the skin of the patient. The example of FIGURE 3 thus applies medicaments transdermally, that is, directly through the skin. The top layer of the skin is the stratum- corneum (SC), the main layer insuring barrier properties of the skin, which essentially consists of dead cells (corneocytes) surrounded by lipid bilayers. Due to their respective composition and structures, the stratum corneum is mostly hydrophobic and impermeable while the lower layers, epidermis and dermis, are mostly hydrophilic. In a transdermal injection system, the fluid to be dispensed is accelerated to speeds high enough to disrupt the stratum corneum and to penetrate into the epidermis and dermis, accessing peripheral blood vessels. Such injection systems are able to penetrate the multiple layers constituting the skin and deliver drugs into the micro-vascularization of the dermis (subdermal injection), thereby achieving systemic drug delivery. The energy in these systems is usually provided by: spring-loaded systems, gas-discharge, or energetic materials, electric discharges and piezoelectric actuators. In the example of FIGURE 3, an injection chamber 74 containing the medicament to be applied is located above the nozzle. A piston 76 is actuated to compress the fluid in the injection chamber, thereby ejecting the fluid through the nozzle. The piston is moved by an actuator in the actuator chamber 78, which can utilize one of the above mentioned energy mechanisms. The actuator is activated by a trigger circuit 80 in response to a trigger circuit applied by the defibrillator/monitor .

FIGURE 4 illustrates an example of an injector of the present invention which is energized by the gas discharge of a CO₂ cartridge 82. The injector is contained in a housing 90. The discharge is triggered by a trigger 84 in response to a signal applied over a conductor 86 from drive electronics 102 of the defibrillator/monitor 100. The discharge of gas from the CO₂ cartridge 82 causes the piston 76 to move to the left, compressing the medicament in the reservoir or injection chamber 74 and ejecting the medicament through the nozzle 72.

FIGURE 5 illustrates another example of an injector of the present invention which is energized by a piezoelectric actuator 88. When a drive signal from the drive electronics 102 is applied to the actuator 88 by way of the conductor 86, the piezoelectric actuator moves the piston 76 to the left, compressing the medicament in the reservoir or injection chamber 74 and ejecting the medicament through the nozzle 72.

FIGURE 6 illustrates another piezoelectrically driven injector of the present invention. In this example the medicament contained within the reservoir 74 flows into an injection chamber of a piezoelectric actuator 89. When the actuator is pulsed by a signal provided by the drive electronics 102 over a conductor 86, the actuator ejects medicament through a nozzle 72 attached to the piezoelectric actuator 89. A more detailed drawing of the piezoelectric actuator 89 is shown in FIGURE 7. The actuator includes a small bulk piezoelectric transducer 92 which has typical dimensions ranging from lxlxl mm³ up to 5x5x15 mm³. The piezoelectric transducer 92 is formed of multi layer ceramic which is mechanically connected to both the top of its casing and a flexible membrane 94 by a support structure 93. The membrane is supported below by a support structure 95 which extends circumferentially around a fluid chamber 96 except for the narrow access of an intake channel to a fluid intake 98. The control lines 86 connect the piezoelectric transducer 92 to the drive electronics 102. During actuation of the transducer 92, the piezoelectric transducer expands and pushes on the flexible membrane 94. This will compress the fluid in the fluid chamber 96, resulting in a pressure build-up in the chamber and as a consequence a fluid flow out of the nozzle 72, which exhibit a diameter typically ranging from 10 to 200 μm and a length between 50 to 200 μm. As soon as the driving of the piezoelectric transducer stops, both the piezoelectric transducer 92 and the membrane 94 return to their rest states and fluid will enter the fluid chamber through the intake channel by capillary force and, in some cases, pressure drop caused by the membrane displacement. The fluid intake channel 98 accesses the fluid in the fluid reservoir 74. A tubing connector may be employed as shown if desired to connect to a remotely located fluid reservoir.

In order to generate a high-speed jet the actuator housing has to be mechanically as stiff as possible. If there is too much mechanical deformation of the housing during driving of the transducer, the pressure in the fluid chamber will be too low to the generate a high speed jet of fluid. The material of choice for the construction of the housing is stainless steel, but other materials with the appropriate mechanical properties can be used such as aluminum, ceramic, glass, bronze, or brass, in each case with an appropriate biomechanical coating if needed.

The piezoelectric transducer 92 is driven using a voltage step function which is applied to the transducer. In normal operation, the height of the voltage step can vary between 0 to 100 volts. Increasing the voltage increases the speed of the fluid jet. The length of an applied pulse normally varies between 10 and 500 μs . Increasing the pulse length will influence the volume of the ejected jet and to a certain extent also the speed. By changing the repetition rate of the pulse, the amount of ejected fluid per second can be changed. Common frequencies are between 1 to 1000 Hz. Dosing at low speed requires a square voltage pulse, whereas high speed jetting requires a sudden volume change by a stepwise change in voltage level. In the high speed jet mode of operation, high voltages typically ranging from 20 to 100 volts are applied to the piezoelectric element, thereby creating large volume displacements in the nozzle chamber ranging from 1 to 8 nl . The ejection speeds range from 10 to 150 m/sec. High speeds ranging from 60 to greater than 200 m/sec for transdermal injection are achieved by driving the piezoelectric element with a step-wise change in voltage of a minimal duration ranging from 10 μs to 500 μs . In a dispensing mode of operation the device operates with a low volume displacement, and acts as a highly reliable pump for accurately controlled small dosage. In this mode, the piezoelectric transducer is driven with low voltage square wave voltage pulses.

In accordance with a further aspect of the present invention the medicament injector may be integrated into a patient electrode which may also be used for ECG signal sensing and the application of defibrillation shocks as shown in FIGURE 8. This example illustrates a patient electrode including a conductive layer 202 covered on its patient-facing side with a conductive adhesive layer 204. The medicament injector 89 is located above the conductive layer 202 with its nozzle directed through a hole in the conductive layer. The injector is connected to a trigger lead 86 and, in a particular implementation, may have a fluid intake 98 coupled to an external medicament reservoir. The upper surface of the electrode and injector is covered with a nonconductive substrate 200.

FIGURE 9 shows a pair of patient electrodes with an embedded medicament injector in accordance with the principles of the present invention in a perspective view. The electrode pads 200 are comprised of two components, the first component being the electrode layer 220 and the second component being the releasing layer 240. An advantage of this two-part construction is that it streamlines the use of the electrodes to two steps: deployment and attachment. The electrode is deployed with one motion prior to applying the electrode to the patient. This construction eliminates additional steps, such as opening electrode packaging and removing the electrodes prior to applying the electrodes to the patient. One side of each component 220, 240 forms a non-conductive outer sealing layer 206, 242. In a preferred implementation, the outer sealing layer is a coated outer sealing layer formed from heat sealing material, such as polyethylene coated polyester or polyethylene coated foil. The electrode layer 220 is formed from the outer sealing layer 206 adhered to a non-conductive layer 228 with an adhesive. An electrode disk 202 is adhered to the non-conductive layer 228 of the outer sealing layer using an appropriate adhesive. The electrode disk 202 is formed of a suitable conductive material such as 2 mil tin and is attached to the interior surface of the outer sealing layer 206 with a suitable medical grade adhesive. The electrode disks are electrically connected to a lead wire 230 between the non- conductive sealing layer and the electrode disk on the outer surface of the electrode disk. The inner surface of the electrode disk is covered with a layer of conductive gel 204. A suitable conductive gel would be, for example, RG 63T hydrogel. The conductive gel has adhesive qualities that enable the gel to adhere to the skin of the patient. As will be appreciated by those skilled in the art, other gels may be used without departing from the scope of the invention. Additionally, the electrode layer may be formed so that one end forms a pull tab 232. In a preferred embodiment, the electrode is connected to the lead wire 230 which is connected to an electrode connector 236 or directly connected to the defibrillator. The lead wire 230 may be attached to a ring terminal (not shown) prior to attaching to the electrode disk 202. Further, a washer may be provided between the ring terminal and the electrode disk 202 to improve the electrical connection. Finally, an insulating disk may be provided between the electrode disk 202 and the washer. The releasing layer 240 is formed from an outer sealing layer 242 which is adhered to a non-conductive layer 246 with the use of an appropriate adhesive. In a preferred embodiment, the non-conductive layer 246 is formed of a silicon coated polypropylene impregnated material. The releasing layer 240 is formed so that one end forms a pull tab 248 thus allowing the electrode conductive surface to be exposed with a single pulling motion when grasping pull tabs 232 and 248. FIGURE 10 illustrates one of the electrode pads of FIGURE 9 with the embedded medicament injector in a partial cross-sectional view. In FIGURE 10 the outer sealing layers 206, 242 are shown sealed at opposite ends of the electrode. The conductor 230 leading to the electrode disk 202 and the conductor 86 which carries the trigger signals to the injector mechanism 54, not shown in this illustration, pass through this seal. The conductor 230 is connected to the electrode disk at the connection block 234, which may include the ring terminal, washer, and insulating disk as previously described. When the pull tabs are grasped and pulled apart the two components of the electrode pad are separated and the releasing layer, including the outer sealing layer 242 and the adhesively attached non-conductive layer 246 fall away, exposing the conductive gel 204 on the electrode disk 202. The rescuer may hold a grip element 252 on the outer surface of the outer sealing layer of the electrode layer 220 while positioning the electrode layer for proper placement on the skin of the patient. The electrode disk 202 will now sense the patient's ECG signal, which is analyzed automatically by the defibrillator/monitor or directly by a trained rescuer to determine whether a defibrillating shock should be applied. If a shock is to be applied the rescuer will depress the shock button on the defibrillator/monitor to apply the shock .

In accordance with the present invention a medicament injector 54 is enclosed in the electrode layer 220 between the non-conductive layer 228 and the outer sealing layer 206. In this example the injector 54 is adhesively secured in place between these two layers. If the patient has not been resuscitated and a normal heart rhythm restored following application of a shock protocol which may include, for example, two series of shocks, the rescuer may actuate one of the controls 32 on the defibrillator/monitor to transdermally inject a drug such as epinephrine through the patient's skin surface. The defibrillator/monitor applies a trigger pulse to the injector actuator 78 which causes the piston 76 to compress the fluid in the fluid chamber 74 and eject the epinephrine through the nozzle 72 which extends into the gel layer 204 through a hole in the electrode disk. The epinephrine will help concentrate any flow of blood to the head to stabilize the patient until additional expert care or other drug compounds can be administered. FIGURE 11a is a partial view of another electrode pad 200 constructed in accordance with the present invention. This pad includes an optically transparent inspection window 260 through the outer sealing layer 206 of the electrode pad. Epinephrine solutions generally have a finite shelf life.

Furthermore, instructions for some compounds specify that epinephrine can be stored at temperatures of up to 84.1 degrees F (28.9 degrees C) for up to 45 days and can tolerate sudden temperature increases of up to 125 degrees F (51.7 degrees C) for a cumulative time of 795 minutes (13.25 hours) before degradation occurs. Temperature and relative humidity sensors can be incorporated in the pad storage unit or the pad itself to periodically monitor these parameters. In addition, epinephrine compounds generally need to be shielded from UV radiation. Upon degradation, the color of the epinephrine solution often becomes slightly yellow of pinkish. A small optical window 206 in the defibrillator pad enables the epinephrine solution in the reservoir 74 to be visually inspected prior to use. In the example of FIGURE lib the appearance of the epinephrine in the reservoir is monitored by a simple module 270 combining an LED source, an optical filter and a photodiode. This module can be actuated regularly by a timer or self- test circuitry to insure that the optical absorption of the epinephrine in the reservoir 74 has not changed. In case of a detected change, the defibrillator can alert the user by an audible or visible display message for the need of maintenance.

One skilled in the art will recognize that the injector 54 may be connected to the defibrillator/ monitor separate from the defibrillation electrodes, with its own adhesive for attachment to the skin of the patient and injection of the epinephrine. It is also possible for a skilled medical practitioner to manually hold the injector against the skin of the patient while the drug is administered instead of adhesively attaching the injector to the skin. It will also be appreciated that drugs can be injected in response to the detection of other physiological conditions such as blood oxygen or CO₂ levels, body temperature, heart rate or other symptomatic conditions .

Claims

WHAT IS CLAIMED IS:

1. An external defibrillator comprising: a pair of electrodes operable to deliver a defibrillation shock and to receive ECG signals; a controller, responsive to the ECG signals which acts to analyze the ECG signals to determine whether a defibrillation shock is advised; and a medicament injector coupled to the defibrillator and operable to inject a medicament.

2. The external defibrillator of Claim 1, wherein the medicament injector is embedded into one of the electrodes.

3. The external defibrillator of Claim 2, wherein the electrode includes a conductive layer which is coated with a conductive adhesive..

4. The external defibrillator of Claim 3, wherein the medicament injector includes a nozzle through which a drug is ejected, the nozzle extending through a hole in the conductive layer of the electrode .

5. The external defibrillator of Claim 1, wherein the medicament injector includes an injection device which operates to produce injection energy, the device comprising one of a compressed gas, a spring, an electric discharge, or a piezoelectric device .

6. The external defibrillator of Claim 5, wherein the injection device is actuated by a trigger signal provided by the defibrillator.

7. The external defibrillator of Claim 6, wherein the injection device includes a piezoelectric element, a fluid chamber, and a nozzle, wherein actuation of the piezoelectric element by a trigger signal compresses fluid in the fluid chamber and expels the fluid through the nozzle.

8. The external defibrillator of Claim 1, wherein the medicament injector includes: an actuation device; a piston moved by operation of the actuation device; a fluid chamber, the contents of which is compressed by movement of the piston; and a nozzle coupled to the fluid chamber through which compressed contents of the fluid chamber is ejected.

9. The external defibrillator of Claim 8, wherein the actuation device is responsive to a trigger signal produced by the defibrillator to eject a drug compound through the nozzle.

10. The external defibrillator of Claim 9. wherein the drug compound comprises epinephrine.

11. The external defibrillator of Claim 1, wherein the medicament injector further includes an adhesive for attachment of the injector to the skin of a patient during injection of a medicament.

12. A method of operating an external defibrillator comprising: applying electrodes to a subject; receiving ECG signals; analyzing the ECG signals to determine whether a defibrillation shock is advised; delivering a defibrillation shock; and following delivery of a defibrillation shock, applying a medicament by means of a medicament injector controlled by the defibrillator.

13. The method of Claim 12, wherein following delivery further comprises following delivery of a defibrillation shock which fails to resuscitate the subject .

14. The method of Claim 12, wherein following delivery further comprises injecting epinephrine by means of an injector controlled by the defibrillator.

15. The method of Claim 12, wherein applying electrodes further comprises applying an electrode which includes a medicament injector controlled by the defibrillator.

16. The method of Claim 12, further comprising adhesively attaching a medicament injector to the skin of the subject.

17. The method of Claim 12, wherein applying a medicament further comprises actuating a medicament injector from the defibrillator to inject a drug transdermally .

18. The method of Claim 17, wherein actuating a medicament injector further comprises triggering a medicament injector powered by one of a compressed gas, a spring, an electric discharge, or a piezoelectric device.

19. A device which administers a medical solution to a patient comprising: a sensor which receives physiological signals from a patient; a controller, responsive to the physiological signals which operates to analyze the physiological signals to determine whether a medicament should be delivered to the patient; and a medicament injector coupled to the controller and adhesively attached to the skin of a patient and responsive to a delivery signal to inject a medicament .

20. The device of Claim 19, wherein the medicament injector further includes an optical window through which a condition of the medicament can be observed.

21. The device of Claim 19, wherein the medicament injector further includes a sensor in proximity to the medicament and coupled to the controller for sensing a condition of the medicament, wherein the condition of the medicament is reported to the controller.