FIELD AND BACKGROUND OF THE INVENTION The present invention relates to an emergency medical kit for rendering emergency medical treatment to a patient, and also to a respiratory pump and a face mask particularly useful in such a kit. The invention is particularly described below with respect to an automatic, simple to operate, emergency respiratory and defibrillator system that can be successfully operated by a bystander during emergency conditions and before the arrival of a professional medical team to the scene. Apparatus constructed in accordance with the present invention may contain advanced Human Machine Interface (HMI) and a control system facilitating a medical treatment for patients of different ventilation requirements and at different medical scenarios of cardiac arrest and respiratory emergencies.

The rationale behind the invention is the vital need for improving the survival rate of cardiac arrest victims. Cardiac arrest is the underlying cause of sudden death in two-thirds of out-of-hospital deaths. An early start of cardiopulmonary resuscitation and for early defibrillation is vital in most cases, since a delay of even a few minutes may lessen the chances of the patient's recovery. Unfortunately, in most emergency conditions, an Intensive Care Unit (ICU) is not immediately available, and critical time may be lost.

Since bystanders at the scene of an unexpected cardiac emergency are faced with a sudden crisis, they may feel panicky, anxious and helpless. Most people have no skills in performing basic cardiopulmonary resuscitation. Those who have some knowledge often fear catching diseases (e. g. AIDS, Hepatitis) by mouth-to-mouth ventilation (an inherent part of the CPR) or are repelled by the patient's physical characteristics (the presence of saliva, blood or emesis) or are concerned of making wrong decisions leading to further damage to the patient. As a result, early Cardiopulmonary Resuscitation (CPR) by bystanders starts in only 10-30 percent of witnessed cardiac arrest cases.

Recently, a large variety of Automatic External Defibrillator (AED) devices required for the Early Defibrillation stage of the"chain of survival"concept have become available in public places. In spite of their user-friendliness in analysing the patient's cardiac condition, and the simplicity of activating the electric shock, mouth-to-mouth ventilation is needed as an integral part of their operation. This limits the wide use of said devices by bystanders. Furthermore, even in cases where CPR starts, if ventilation is done without the supply of oxygen but with air, this may definitely reduce survival rate.

Thus, there is an urgent need for an emergency kit which can be used by bystanders during ex-hospital conditions to render vital medical treatments in emergency situations.

The prior art has attempted to address the need for providing non-professional persons equipment intended for emergency situations. Examples of such equipment are described in U. S. Patents 4, 197, 842, 4,198, 963,4, 297,990, 5,520, 170,5, 782,878, 5,857, 460,5, 873,361, 5,975, 081,5, 979,444, 6,029, 667,6, 062,219, 6,327, 497,6, 351,671, 6,402, 691,6, 428,483, 6,459, 933,6, 488,029 and 6,544, 190.

Some of the existing Continuous Positive Airway Pressure (CPAP) ventilators controllers are based on linear or non-linear electronic circuits, which represent the respiratory cycle. These models are used to derive a transfer function of circuit pressure, flow and a real time estimate of resistance, elasticity, lung compliance of the patient's respiratory system, and also to estimate the connecting tube compliance. These estimates preferably utilize non-invasive measurements of inlet flow and pressure, and also use real time closed-loop feedback systems. Examples, of prior art models and systems used for this purpose are described in U. S. Patents 3,036, 569,5, 752,509, 6,068, 602,6, 142,952, 6,257, 234,6, 332,463, 6,390, 091 and 6,557, 553.

The proper use of a respiratory face mask requires a high degree of skill and experience. A non-professional CPR operator is not able to properly use such a mask without advanced detailed guidance. Furthermore, a good mask-to-face seal has been attained in many instances only with considerable discomfort for the user. Examples of face masks described in the prior art appear in U. S. Patents 2,254, 854,2, 931,356, 4,739, 755,4, 907,584, 4,971, 051,5, 181,506 and 5,540, 223. Nevertheless, there is still an urgent need for providing a face mask that can be used by a non-professional operator for

assuring best quality of ventilation and the ability to ventilate a patient with oxygen- enriched air.

OBJECTS AND BRIEF SUMMARY OF THE INVENTION An object of the present invention is to provide an emergency medical kit enabling ex-hospital cardiopulmonary resuscitation to be more effectively rendered to a patient by a bystander or non-professional in one or more of the above respects. Another object of the invention is to provide a respiratory pump which may be efficiently driven and which provides a wide degree of controls. A further object of the invention is to provide a face mask particularly useful by a bystander to render an emergency medical treatment to a patient.

According to one aspect of the present invention, there is provided an emergency medical kit for rendering emergency medical treatment to a patient, comprising: a housing, a pressurized-oxygen container within the housing; a face mask within the housing and removable therefrom for application to the face of a patient requiring emergency medical treatment; and a respiratory pump within the housing; the respiratory pump being connectable to the pressurized-oxygen container so as to be driven thereby to supply oxygen to the face mask for inhalation by the patient, and to discharge exhalations of the patient to the atmosphere.

According to further features in the described preferred embodiment, the respiratory pump includes a pump housing having first and second end walls at opposite ends thereof ; a partition wall between the end walls; a first piston movable between the first end wall and the partition wall and defining a first chamber with the first end wall, and a second chamber with the partition wall; a second piston movable between the partition wall and the second end wall, and defining a third chamber with the partition wall, and a fourth chamber with the second end wall; a stem coupling the first and second pistons for reciprocation together; and a valve assembly connectable to the pressurized- oxygen container for utilizing the energy of the pressurized oxygen therein to reciprocate the pistons within their respective chambers.

In the described preferred embodiment, the pressurized-oxygen container is connected to the first chamber by a first tube; the first chamber is connected to the face mask by a second tube; and the face mask is connected to the third chamber by a third tube.

According to still further features in the described preferred embodiment, the face mask includes a plate configured to cover the nose and mouth of the patient receiving the mask, and a flexible seal around the circumference of the plate engageable with the face of the patient for sealing the interior of the mask with respect to the outside atmosphere; the flexible seal including a deformable fluid compartment, and a pressure sensor sensing the pressure therein; the mask further including an indicator controlled by the pressure sensor for indicating, according to the sensed pressure, whether the face mask is properly sealed with respect to the face of the patient.

According to a still further feature of the invention, the kit further comprises a neck rest removably disposed within the housing; the neck rest being configured for supporting the neck of a patient in need of medical treatment, when the patient is in a reclining position, to facilitate application of the face mask to the patient, the delivery of oxygen for inhalation by the patient, and the discharge to the atmosphere of the exhalations of the patient with minimum flow resistance.

According to yet further features, the kit further includes a pulse detector probe for application to the patient to detect the patient's pulse. Preferably, the kit further includes a plurality of electrodes for application to the patient for administering electrical pulse therapy to the patient. The electrical conductors of the pulse detector probe, as well as of the plurality of electrodes, are preferably carried by the feed tube of the mask for connection to an electrical power supply, thereby facilitating the deployment of the pulse detector probe, as well as of the electrodes, in a quick and simple manner.

According to still further features in the described preferred embodiment, the kit further includes a telephone communication system for receiving remote instructions via the telephone, a GPS locator system for determining the location of the patient being treated, a data logging system for logging data inputted or generated during the operation of the system, a visual display for displaying data inputted or generated during the operation of the system, and/or an audio instruction and alarm system for receiving instructional information and/or for operating an alarm under predetermined conditions.

As will be described more particularly below, the foregoing features enable the construction of portable, compact, emergency medical kits which can be used for rendering emergency medical treatments to patients in a manner requiring a minimum of

professional skill and experience such as to enable bystanders or other non-professional persons to render such emergency medical treatments if and when required.

According to still further aspects of the present invention, there is provided a respiratory pump and also a face mask particularly useful in the described emergency <BR> <BR> medical kit, but also useful in many other applications, e. g. , for administering emergency oxygen in an aircraft or for otherwise rendering respiratory assistance to a person whenever it may be desired or required.

Further features and advantages of the invention will be apparent from the description below.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein : Fig. 1 is a three-dimensional view illustrating one form of an emergency medical kit constructed in accordance with the present invention, with the cover of the kit being open to illustrate many of the components therein; Fig. 2 is a block diagram illustrating the main components in the emergency medical kit of Fig. 1; Fig. 3 is a three-dimensional view illustrating the emergency medical kit of Figs.

1 and 2 during use for rendering an emergency medical treatment; Fig. 4 is a front view illustrating the face mask in the emergency medical kit of Figs. 1-3 ; Fig. 5 is a three-dimensional view illustrating the pair of neck rests in the emergency medical kit of Figs. 1-3 ; Figs. 6a, 6b and 6c illustrate three stages in the operation of the ventilator pump in the emergency medical kit of Figs. 1-3 ; and Fig. 7 is a schematic diagram illustrating an equivalent circuit that may be used for modeling the control parameters of the illustrated system.

It is to be understood that the foregoing drawings, and the description below, are provided primarily for purposes of facilitating understanding the conceptual aspects of the invention and various possible embodiments thereof, including what is presently considered to be a preferred embodiment. In the interest of clarity and brevity, no attempt

is made to provide more details than necessary to enable one skilled in the art, using routine skill and design, to understand and practice the described invention. It is to be further understood that the embodiments described are for purposes of example only, and that the invention is capable of being embodied in other forms and applications than described herein.

DESCRIPTION OF THE ILLUSTRATED PREFERRED EMBODIMENT Overall Construction As indicated earlier, the emergency medical kit illustrated in the drawings is designed for use by a non-professional person, such as a bystander, for rendering a respiratory and/or defibrillator treatment to a patient or other person under emergency conditions. The emergency medical kit, as shown in Figs. 1 and 3, includes a housing, generally designated 10, having a cover 12 for opening the housing in order to provide access to its various components. When cover 12 is closed, it provides a relatively small, compact, portable unit that may be conveniently carried to the scene of an emergency, or that may be conveniently stored in a suitable nearby location for use during an emergency. The main operational components of the illustrated emergency medical kit are more particularly shown in the block diagram of Fig. 2.

As further shown in Figs. 1 and 3, housing 10 includes a container 14 of pressurized oxygen. Container 14 is normally retained within housing 10 during use of the kit, but can of course be removable therefrom, e. g. , for replacement or recharging purposes.

Housing 10 further includes a face mask, generally designated 20 and more particularly illustrated in Fig. 4. Face mask 20 is removable from housing 10 for application to the face of a patient requiring the emergency medical treatment, as shown in Fig. 3.

Face mask 20 is not viewable in Fig. 1 since it is covered by a neck rest, generally designated 30, which is also removably disposed within the housing and which must be removed before access is provided to the face mask underlying the neck rest. The neck rest is configured for supporting the neck of a patient in need of medical treatment, when the patient is in a reclining position, to facilitate application of the face mask to the

patient, the delivery of oxygen for low-resistance inhalation by the patient, and the low- resistance discharge to the atmosphere of the exhalations of the patient.

Preferably, the illustrated emergency medical kit includes two such neck rests as shown in Fig. 5 to be described more particularly below. One neck rest is dimensioned for use with an adult, and the other is dimensioned for use with a child.

The illustrated emergency medical kit further includes a respiratory pump, generally designated 40, within housing 10. Respiratory pump 40 is controlled by a valve assembly, generally designated 50, to connect, via a plurality of flexible feed tubes, the pressurized-oxygen container 14 to the face mask 20 such that the pump is driven by the pressurized oxygen to supply oxygen to the face mask for inhalation by the patient, and to discharge the exhalations of the patient via the face mask to the atmosphere. Pump 40 and valve assembly controller 50 controlling it are normally retained within housing 10 during the use of the emergency medical kit, but of course can be removable therefrom, e. g. , for replacement or repair purposes.

Thus, as shown particularly in Fig. 3, pump 40 is connected to the pressurized- oxygen container 14, via the valve assembly controller 50, by means of a first tube 50a (which corresponds to tube T1 in Figs. 6a-6c described below), which remains within the housing 10, with the container and the pump, during the normal use of the kit when rendering an emergency treatment; whereas the pump is connected by a long flexible tube 50b (containing the two feed tubes T2, T3 described below with respect to Figs. 6a-6c) to the face mask 20 to enable the face mask to be removed from the housing 10 and applied to the face of the patient P requiring the treatment.

The foregoing components of the illustrated emergency medical kit may be used for rendering respiratory assistance to a patient whenever required. The illustrated kit, however, is particularly useful for performing cardio-pulmonary resuscitation (CPR) and/or cardiac defibrillation under emergency conditions. For this purpose, the illustrated kit further includes a pulse detector probe 60 for application to the patient (e. g. , the patient's head as shown in Fig. 3) in order to detect the patient's pulse. The illustrated kit further includes a plurality of electrodes, designated 61 and 62 in Fig. 3, for administering electrical pulse therapy, e. g. , defibrillation pulses, to the patient. Electrodes 61,62 are

also used for diagnosing and monitoring the electro-cardiac condition of the patient by detecting the patient's heart signals.

As shown in Fig. 2, the overall operation of the various components of the system included in the kit are controlled by a microprocessor, generally designated 70, also included within housing 10. Microprocessor 70 includes a number of inputs from the patient P, as illustrated by inputs 71 in Fig. 2, as follows: carbon dioxide (CO2) concentration in the exhalations, as detected by a CO2 detector 29a (Fig. 4) in the gas exhalation path of the face mask 20 as will be described more particularly below; pulse signals from the pulse detector probe 60 (Fig. 3), which is preferably a pulse-oximetry detector; and heart signals which may be detected by the electrodes 61,62.

Microprocessor 70 includes a further input signal 72 from the face mask 20 indicative of the seal pressure in each of its three seal compartments, as will be described more particularly below ; and the ventilation pressure and flow signal 73, also from a sensor 29 (Fig. 4), inside the face mask 20, as will be described more particularly below.

The main output of microprocessor 70 is a ventilator control signal 74 which controls the valve assembly 50 to control the respiratory pump 40, as will also be described more particularly below. Microprocessor 70, however, includes a number of additional outputs, as follows: An output signal is produced to the defribillator, as shown at 75, e. g. , the cardiac electrode 61,62 (Fig. 3), when a defribillator activating button 75a (Figs. 1,3) is depressed.

An output is also produced to a visual display 76 for displaying operational instructions to the operator generated by microprocessor 70 during its operation. The outputs of microprocessor 70 are further monitored by a main BIT (built-in-test) module which automatically monitors any fault in the system and controls, via the microprocessor, an audio instruction and/or alarm module 78. The main BIT module 77 is backed-up by an independent BIT module 77a which is responsible to produce an independent alarm if the main BIT module 77 fails. A failure is defined as existing when module 77 fails to send module 77a a signal during a predetermined time interval.

Microprocessor 70 further includes an output to a data logger module 79, which records all the patient records and treatments received by the patient during the event.

As further shown in Fig. 2, microprocessor 70 may also be used for enabling remote telephone communication and/or GPS location, via a remote telephone communication module 80 and GPS locator module 81. Thus, the emergency medical kit may be used for communicating with professional persons at a remote location, e. g. , via a cellular telephone, for receiving treatment guidance, for advising such remotely-located persons of the exact location of the patient receiving the emergency treatment, and/or for directly defibrillating the patient.

As shown in Figs. 1 and 3, the visual display 76 is located on the inner surface of the cover 12 so as to be viewable when the cover is opened. It may be a touch screen for inputting data. The inner face of the cover further includes an alarm indicator 78a, such as a flashing light, to produce an optical alarm, or a speaker to produce an audio alarm, one or both of which may be activated by the alarm module 78 (Fig. 2) upon the occurrence of an alarm condition.

The inner face of cover 12 further includes a manual control button 82 which may be depressed to start the system, to open an electric valve 54a (Figs. 1, 3) between the oxygen container 14 and the pressure regulator 54, and to input, (e. g. , prior to or during the medical treatment) basic information relating to the patient being treated and the medical scenario involved, e. g. , cardiac arrest, respiratory emergency, etc. The microphone of the telephone communication 80 enables this data to be verbally inputted and recorded.

As the system should always be kept at a high reliability level, ready for operation in a very short notice, the apparatus is always in a self-testing condition by the main BIT 77, as well as by a back-up BIT 77a. Usually, cover 12 is closed during the standby condition of the kit. If a fault is diagnosed by the BIT module 77, the fault will be indicated on a screen 84, and/or by the light indicator 78b, carried by a ledge 85 of the housing 10 which is not covered by the cover 12 in the closed condition of the cover.

In addition, if alarm 78a carried by the cover is an audio alarm, this alarm will also be actuated.

To enable the kit to be used during emergency conditions, the kit also includes its own battery power supply, shown at 86 in Figs. 1-3. If the kit is to be carried by a

vehicle, the kit could include merely a connector to the vehicle battery, e. g. , via the cigar lighter terminal.

Construction of Face Mask 20 (Fig. 4) The construction of the face mask 20 is best seen in Fig. 4. It includes a rigid transparent frame plate 21 of generally triangular configuration such that the narrow end 21a covers the patient's nose, and the wide end 21b is aligned with the patient's chin so as to cover the patient's mouth. Triangular frame 21 is formed with an opening for receiving the ends of two feed tubes T2, T3 to be received in the mouth of the patient.

Face mask 20 further includes a flexible seal 23 around the circumference of plate 21 engageable with the face of the patient receiving the mask for sealing the interior of the mask with respect to the outside atmosphere. Flexible seal 23 is divided into three separate air compartments 23a, 23b, 23c, each including a pressure sensor 24a, 24b, 24c, respectively. Each pressure sensor controls, via microprocessor 70, a green-light indicator 25a-25c or a red-light indicator 26a-26c according to the pressure sensed by the respective sensor. Thus, if the mask is properly applied over the patient's face, the pressure in all three compartments 23a-23c will be above a predetermined value needed for proper sealing, and therefore all three green indicator lights 25a-25c will be energized. On the other hand if any side of the mask is not properly pressed against the patient's face, the red indicator light 26a-26c for the respective compartment will be energized rather than the green indicator light.

Mask 20 illustrated in Fig. 4 further includes a maximum negative-pressure release valve 27, and a maximum positive-pressure release valve 28 to release the pressure within the mask should it exceed a predetermined negative or positive pressure.

Mask 20 further includes a pressure sensor 29 for sensing the pressure within the mask, and a carbon dioxide (CO2) sensor 29a for sensing the C02 concentration of the exhalations. The sensed pressure and C02 concentration are inputted into microprocessor 70 via input line 73 (Fig. 2).

As shown particularly in Fig. 3, the face mask 20 also carries the pulse detector probe 60 and the plurality of electrodes 61,62 so as to facilitate the deployment of probe 60 and electrodes 61,62 when the face mask is removed from housing 10 for application to the face of a patient requiring the medical treatment. Thus, pulse detector probe 60 is

connected, via microprocessor 70, to the power supply 86 within housing 10 by an electrical conductor 63 carried by the flexible feed tube 50b connecting the mask to the pump 40, and electrodes 61,62 are similarly connected by electrical conductors 64,65 carried by the flexible feed tube 50b. Such an arrangement is not only compact for accommodation within housing 10, but also greatly facilitates the application of the probe 60 and electrodes 61,62 to the patient when the mask 20 is removed from the housing for application to the patient.

The Neck Rest 30 (Fig. 5) While Figs. 1 and 3 illustrate only a single neck rest 30 included in the emergency medical kit, preferably there would be two such neck rests, as illustrated by neck rest 30 and 30a in Fig. 5. Both neck rests 30 and 30a are similarly configured for supporting the neck of a patient when in a reclining position. Neck rest 30 would be dimensioned for supporting the neck of an adult, whereas neck rest 30a would be dimensioned for supporting the neck of a child. As shown in Fig. 5, they are configured so as to be in a nested relationship when disposed within housing 10 of the emergency medical kit.

Thus, as shown in Fig. 5, each of the neck rests 30,30a, includes a pair of spaced, parallel side walls 31,32, 3 la, 32a engageable at their lower ends with a <BR> horizontal surface, e. g. , the ground or floor, receiving the patient in a reclining position.

Both neck rests further include an upper wall 33,33a, of concave configuration for supporting the neck of the patient when received in the reclining position, as shown in Fig. 3.

As indicated earlier, neck rest 30 (preferably with neck rest 30a) is disposed within housing 10 of the emergency medical kit to overlie the face mask 20, as shown in Fig. 1. This better assures that the neck rest will be removed from the kit so as to enable it be to properly deployed to receive the patient, before the face mask is removed from the kit for application to the patient.

The Respiratory Pump 40 (Figs. 2 and 6a-6c) As indicated earlier, the respiratory pump 40 included within housing 10 of the emergency medical kit is controlled by the valve assembly 50 so as to be driven by the

pressure within the pressurized-oxygen container 14, to supply oxygen from the pressurized-oxygen container 14 to the face mask 20 for inhalation by the patient, and to discharge the exhalations of the patient to the atmosphere. This is all done in a controlled manner as will be described more particularly below in the description of the overall operation of the system.

Respiratory pump 40 includes a pump housing 41 having an end wall 41 a at one end, an end wall 41b at the opposite end, and a partition wall 41c between the two end walls. Pump 40 further includes a first piston Pi movable between end wall 41a and partition wall 41c, to define a first chamber C I with end wall 4 1 a and a second chamber C2 with the partition wall 41c. pump 40 further includes a second piston P2 movable between partition wall 41c and end wall 41b, to define a third chamber C3 with the partition wall 41c, and a fourth chamber C4 with end wall 41b. Pump 40 further includes a stem 42 coupling the two pistons Pi, P2 for reciprocation together.

Chamber Cl includes a pressure-release valve 43 to prevent an excessive pressure within that chamber. Chamber C2 is preferably continuously vented to the atmosphere.

Piston P2 carries one or more one-way valves 44a, 44b, permitting air flow from chamber C3 into chamber C4, but blocking air flow from chamber C4 to chamber C3.

Respiratory pump 40 further includes a spring 45 interposed between piston Pi and partition wall 41c for urging piston Pl to contract chamber Cl and expand chamber C2. As will be described more particularly below, piston Pi (and with it piston P2) is driven in one direction by the high-pressure of the oxygen container 14, and is driven in the opposite direction by spring 45.

Respiratory pump 40 further includes a tube connector 46 leading into chamber Ci, and a second tube connector 47 leading into chamber C3.

Valve Assembly Controller 50 (Figs. 2 and 6a-6c) Valve assembly controller 50, which controls the respiratory pump 40, includes a block 51 formed with a plurality of passageways PWI, PW2 and PW3, therethrough.

Valve assembly controller 50 further includes a valve member 52 movable within a further passageway PW4 in block 51 by means of an electrical motor 53 to control fluid flow through passageways PWI-PW3. Thus, valve member 52 is in the form of a

cylindrical stem having reduced-diameter sections at 52a, 52b, to define three valves Vi, V2, V3 with respect to passageways PWI, PW2, PW3, respectively, which may be selectively opened or closed, according to the position of valve stem 52 within passageway PW4.

Passageway PWI is connected at one end to the pressurized-oxygen container 14 via a tube Tl and a pressure regulator 54. The opposite end of passageway PWI is connected to passageway PW2 at the side thereof facing the respiratory pump 40.

Passageway PW2 is connected at the latter end to tube connector 46 of the respiratory pump 40, and at the opposite end to the face mask 20 via flexible tube T2.

Passageway PW3 is connected at one end to tube connector 47 of the respiratory pump 40, and at the opposite end via a flexible tube T3 to the face mask 20. Tube Tl corresponds to tube 50a shown in Figs. 1 and 3, whereas tubes T2 and T3 are disposed coaxially within the long flexible feed tube 50b shown in Figs. 1 and 3. Flexible feed tube 50b also carries the conductors from sensors 29,29a, 60,61 and 62 to microprocessor 70.

As shown schematically in Figs. 6a-6c, which will be described below in connection with the description of the overall operation of the system, the end of tube T2 includes a one-way valve 55 which permits only inflow of gas (oxygen, as described below) into the face mask, and a second one-way valve 56 which permits only outflow of gas (exhalations) from the mask into tube T3. Thus, a minimum dead space of inflow and outflow gases is achieved.

Valve stem 52 is reciprocated by electrical motor 53 under the control of the ventilator control signal 74 outputted from microprocessor 70. Thus, when motor 53 moves valve stem 52 to the extreme right position as illustrated in Fig. 6a, valves Vl and V3 are open, and valve V2 is closed; whereas when the motor moves the valve stem to the extreme left position as illustrated in Fig. 6c, valves V1 and V3 are closed, whereas valve V2 is open. The opening and closing of these valves drives the respiratory pump 40 to supply oxygen for inhalation by the patient, and to discharge the exhalations of the patient to the atmosphere, as will be described more particularly below.

Overall Operation As indicated earlier, the illustrated emergency medical kit continuously makes a self-check by means of the main BIT module 77, and the independent BIT module 77a. If

a fault is found to be present by module 77, this information will be displayed on screen 84 and/or indicated by the light indicator 78b, even when the cover 12 is in its closed condition closing the housing 10. Independent BIT module 77a has an independent power source and alarm system, and continuously monitors the routine operation of module 77.

In case module 77a detects a problem in module 77, module 77a activates its independent alarm system.

When an emergency condition occurs, cover 12 is opened. At that time, the user may input basic information relating to the patient needing the emergency treatment and the medical scenario existing (e. g. , cardiac arrest, approximate age of the patient), etc.

This information may be inputted via the touch screen 76 or the microphone at the remote telephone communication 80, may be recorded in the data logger module 79, and may be transmitted via the telephone communication unit 80 to a remote location. The specific location of the episode may also be communicated as determined by the GPS locator 81.

Neck rest 30 (or both necks rests 30,30a, Fig. 5) are removed, and the appropriate one (adult or child) is placed under the neck of the patient while in a reclining position. The face mask 20, thus rendered accessible by removal of the neck rest 30, is then applied to the patient's face, with the end of the feed tube 50b (containing tubes Ta, T3, Figs 6a-6c) received in the patient's mouth, and the peripheral seal 23 firmly pressed against the patient's face. If the seal is not properly applied so that one or more sides of the face mask are not firmly pressed against the patient's face, this will be indicated by the energization of a red indicator lamp 26a-26c at the respective side of the mask, rather than a green indicator lamp 25a-25c. Accordingly, the operator will be able to immediately discern and correct any improper sealing of the face mask with respect to the patient's face. In addition, an audible signal will be automatically transmitted by module 78a, and a visual demonstration will be displayed on screen 76.

The pulse detector probe 60 is then applied, e. g. , at the top of the patient's head as shown in Fig. 3, and the cardiac electrodes 62,63 are also applied to the patient's chest.

If needed, the defibrillator module 75 (Fig. 2) may be activated by depressing defibrillator button 75a on the inner face of the cover 12 (Figs. 1,3). The operator may also communicate with a professional health care person to inform that

person of the situation and to receive further instructions via the audio instruction and alarm module 78.

In addition, if no breathing is detected by the carbon dioxide sensor 29a, the respiratory pump 40 is activated by depressing button 82 to activate the valve assembly electric motor 53. Motor 53 reciprocates valve stem 52 of the valve assembly controller 50 first in one direction to one limit position (e. g. , as shown in Fig. 6a) and then in the<BR> opposite direction to the opposite limit position (e. g. , as shown in Fig. 6c). Fig. 6b merely illustrates an intermediate position between the two limit positions of Figs. 6a and 6c.

This reciprocation of valve stem 52 connects the respiratory pump 40 to the pressurized oxygen container 14, to utilize the energy therein to supply pressurized oxygen from container 14 into chamber Cl for later inhalation by the patient, and to discharge exhalations of the patient from chamber C3 to the atmosphere. This is done in the following manner: Assuming the valve stem 52 is in the limit position illustrated in Fig. 6a, in this position valves V I and V3 are opened, whereas valve V2 is closed. Thus, in this position oxygen is supplied from the pressurized-oxygen container 14 via tube Tl passageway PWI and connector 46 to chamber Cl of the respiratory pump 40. This moves piston Pi leftwardly, compressing spring 45, to expand chamber Cl and to contract chamber C2.

Since piston Pl is coupled by piston stem 42 to piston P2, the latter piston will also move leftwardly, thereby expanding chamber C3 and contracting chamber C4. The expansion of chamber Cl fills it with oxygen, and the expansion of chamber C3 draws exhalations from the patient's mask 20 into chamber C3 via tube T3. The one-way valves 44a, 44b carried by piston P2 are closed and thereby retain the exhalations within chamber C3. Opening 44c in chamber C4 permits a free contraction of chamber C4, and also effects the discharge of the air (previous exhalations) within that chamber to the atmosphere during the next cycle.

Thus, during the stroke indicated by Fig. 6a, chamber Cl is filled with pressurized oxygen, while chamber C3 is filled with exhalations from the patient.

Fig. 6b illustrates an intermediate position of valve stem 52, wherein all three valves Vl, V2 and V3 in passageways PWi, PW2, PW3 are closed.

Fig. 6c illustrates the opposite extreme position of the valve stem 52, wherein the previously open valves Vl, V3 (in passageways PWI, PW3, ) are now closed, and the previously closed valve V2 (in passageway PW2) is now open.

In this condition of the respiratory pump, the closing of passageway PWl disconnects chamber Cl from the pressurized-oxygen container 14, thereby permitting the spring 45 within chamber C2 to move piston Pl rightwardly, as shown in Fig. 6c, to contract chamber Cl, and to force the oxygen therein via connector 46, passageway PW2, and tube T2 into the patient's mouthpiece for inhalation by the patient.

In addition, piston P2, rigidly coupled to piston Pl, also moves rightwardly, thereby contracting chamber C3 and expanding chamber C4. This movement of piston P2 permits the gas (exhalations) within chamber C3 to be transferred via the one-way valves 44a, 44b into chamber C4, for discharge from that chamber through opening 44c.

As noted earlier, chambers Cl and C2, as well as the piston Pi movable therein, are of smaller cross-sectional area than chambers C3, C4 and piston P2. Thus, the volume of chamber Cl is less then that of chamber C3 so that the pressure within chamber C3 is less than that within chamber Cl. The control of the end pressure in chamber Cl permits not only to regulate inhalation pressure, but also to regulate the exhalation pressure such that it can even be made sub-atmospheric to aid exhalations from the patient. This control can be effected by controlling the electric motor 53, via the control signal outputted by microprocessor 70 to the ventilator control module 74, to control the movements of the reciprocatory stem 52 of the valve assembly controller 50.

Such an action particularly when accompanied by chest compressions, increases the chances of patient survival if the emergency treatment is taken in time. As shown above, the respiratory pump may be operated according to an Active Compression- Decompression (ACD) mode, and also according to a Positive End-Expiratory Pressure (PEEP) mode, with relative low electric power consumption.

The Electronic Model (Fig. 7) The electronic model of the pneumatic and of the respiratory systems is shown in Fig. 7, schematically indicating the pump 40 (having a sinusoidal operation), the circuit pressure elements, circuit compliance elements, and the one-way flow elements (diodes).

Pm is the pressure in the mask bulk (cmH20); PI is the lung pressure (cmH20); Cin, Cout, Cl and Cb are the entering circuit compliance through connector 46 and tube T2 and the exhaust circuit compliance through connector 47 and tube T3, lung compliance and patient's airway and mask compliance, respectively (liters/cm H20); Rm is the mask sealing resistance (cmH20/liter/sec) represents the rate of sealing; (when the mask is sealed completely, Rm can be considered as infinite); Ra, in and Ra, out are the patient's airway resistance during inhalation and exhalation phases, respectively (cmH20/liter/sec); Rt, in and Rt, out are the connecting circuit resistances during inhalation and exhalation, respectively (cmH20/liter/sec); and Ps is the pressure (sinusoidal) supplied by the ventilator's pump 40 (cmH20). D l, D2, D3, D4, D5 and D6 are ideal diodes. D1 and D5 are conductive during inhalation, while D6 and D2 are in closed condition, and verse versa, during exhalation process. D3 is opened when the pressure in the mask exceeds a maximum positive threshold pressure of Vth, as determined by value 42. D4 is opened when the pressure inside the mask is below a maximum negative threshold pressure-Vth, as determined by valve 43.

The model derives a real time estimate of patient airway resistance, lung compliance, connecting tube compliance and lung elasticity. These estimates are used to regulate pump parameters in real time using closed loop monitoring of output signals.

The illustrated apparatus is able to provide consistent regulation for each individual patient throughout the whole medical treatment as well as automatically adjust itself for wide range of different patients, from small infants to large adults.

Sinusoidal pump 40 is able to provide positive and negative end-expiratory pressures by selecting the oxygen chamber end pressure Cl, taking into consideration the system fixed parameters (the increased volume for the same displacements of pistons Pi and P2, as well as the dynamic parameters at each instant of operation.

The illustrated model allows different resistances at inhalation and exhalation phases. Separation of inhalation and exhalation resistances results from different diameter of the inhalation and exhalation tubes and from possible elasticity differences of the lungs and thorax during inhalation. Prior art considers inhalation and exhalation airway resistances in two alternatives: as linear or as non-linear functions. Recognizing the fact that gas flow through an endotracheal tube may be turbulent, a non-linear approach is recommended: P » Kp * f (t)" P (F) is the pressure due to the flow across the patient airway, f (t) is the bi-directional flow, n is an empirically invariant exponential (usually ranged between 1.4 to 1.7) and Kp is constant within a single breath.

When analyzing the above electronic circuit by using well-known Kirchoff's voltage laws and transferring the results to the frequency domain, a transfer function of circuit pressure to flow at the mask area can be found for inhalation and exhalation phases.

Pressure and flow rate sensors signals may be transmitted via an analog to digital converter (A\D converter) and an anti-aliasing filter. These inputs enable the microprocessor to calculate Cin, Cout, Ca, Ra, in, Ra, out and the mask leakage volume- using standard analytical techniques, such as the recursive least squares method. The output signal generates by the microprocessor are used for controlling and optimizing the pump parameters. Closed-loop method is used for minimizing the error signal and for achieving desired parameters at real time.

It will be appreciated that the described apparatus is very user-friendly, and does not require a high degree of skill or experience on the part of the user. The system may be provided with other detectors and sensors to detect other medical conditions, such as airway obstructions indicated by high impedance pressures, carbon dioxide detectors 29a to analyze the exhalations and thereby to indicate the return of a spontaneous pulse and to prevent hyperventilation. In addition, heart signal sensors may be provided to monitor the cardiac electrical signals.

The pulse probe 60 may be an optical oximetry type detector to monitor the oxygen level of the blood, which would thereby also facilitate the early detection of the return of natural circulation on the part of the patient.

All the operations of the described apparatus are controlled by microprocessor 70 which may be programmed to produce optimal ventilation pressures and flows for patients of different ventilation requirements and involved in different medical scenarios of cardiac arrest and respiratory emergencies.

While the invention has been described with respect to one preferred embodiment, it will be appreciated that this is set forth merely for purposes of example, and that many other variations, modifications and applications of the invention may be made.