Abstract: A chest compressor includes a piston (14) that moves in downward and upward strokes within a cylinder (12), with the piston undergoing a smooth reversal at the bottom of the downward stroke. A compression spring, such as a wave spring (60), is positioned to engage the piston only near the end of its downward stroke, to smoothly reverse the piston motion, limit downward force on the patient at the end of the stroke, and avoid a downward pulse due to the momentum of the downwardly-moving piston. A stop (90, 92) is latchable in an inward position to allow reduction in the piston stroke by engaging an outward flange (52) on the piston before the piston has moved fully downward.

Abstract: A chest compressor includes a piston (14) that moves in downward and upward strokes, with the piston undergoing a smooth reversal at the bottom of the downward stroke. A compression spring such as a wave spring (60), is positioned to engage the piston only near the end of its downward stroke, to smoothly reverse the piston motion, limit downward force on the patient at the end of the stroke, and avoid a downward pulse due to the momentum of the downwardly-moving piston. A stop (90, 92) is latchable in an inward position to allow reduction in the piston stroke by engaging an outward flange (56) on the piston before the piston has moved fully downward.

Abstract: An automatic chest compressor (10) for repeatedly compressing the chest of a patient, is constructed to have a small thickness (H) and light weight so it can be readily carried by an emergency worker. The chest compressor includes a piston support (34) at the top, a pressing part (40) at the bottom that presses towards the chest of the patient, and piston side walls (36) that repeatedly elongate to depress the pressing part. The piston side wall are flexible material that is repeatedly curled and uncurled as the side walls move the pressing part respectively up and down.

Abstract: Devices for treating a patient by measuring a condition, such as the partial pressure of CO2, at a location on a mucosal membrane surface in the mouth region of the patient, includes a sensor (14, 16) with an end (44, 46) that lies against the mucosal surface, and a seal (20) that extends 360° around the sensor end and presses against the mucosal surface. The sensor end and the seal lie on the first end portion (24) of a holder (22) which has a second end portion (26) that presses against the outside of the patient at a location opposite the sensor and seal. The holder is a clasp which can be formed as a single piece of resilient material that extends in a loop, or which can be formed in the manner of a clothespin with a spring that pivots two bars to urge their end portions towards each other.

Abstract: An image is created of blood circulation deep (e.g. a plurality of millimeters) below the surface of living tissue to aid in evaluating a patient. A first beam (26) of circularly polarized light is directed forwardly (F) against an outer surface (14) of the tissue. Light that has penetrated to only a shallow depth before moving rearwardly and out of the tissue remains polarized and is blocked by a filter (38). Light that has penetrated to greater depths (12), is scattered more and becomes depolarized, and a portion of it passes through the depolarizing filter (38) and is focused on a photodetector (48) to create an image. Light spots (54) on the image that move, represent spaces between blood platelets (52) that are moving through a capillary, and indicates the velocity of blood through the capillary.

Abstract: Apparatus is provided for treatment of a victim to reverse cardiac arrest by chest compression and by electrical defibrillation through electrodes applied to the chest area of the victim. The apparatus includes a dielectric layer which is placed on the victim to electrically isolate the rescuer who is performing chest compressions. The protective sheet includes a layer of electrically conductive material sandwiched between two dielectric layers to electrically isolate the rescuer. The sandwiched conductive layer is connected to a location on the body of the victim that is spaced a plurality of inches from each of the electrodes.

Abstract: A method is provided for analyzing the condition of a patient to determine whether or not a defibrillation shock should be applied, without stopping CPR (primarily chest compressions). While chest compressions continue to be applied to the victim, the system differentiates between (1) a perfusing rhythm that has the capability of leading to a beating heart without a shock and (2) ventricular fibrillation (VF) which sometimes occurs in the presence of ventricular tachycardia (VT), in which there is no capability for leading to a beating heart without a shock. Defibrillation shocks should be applied only when needed and that is in the presence of VF and sometimes in the presence of VT.

Abstract: A chest compressor includes a piston (14) that moves in downward and upward strokes, with the piston undergoing a smooth reversal at the bottom of the downward stroke. A compression spring such as a wave spring (60), is positioned to engage the piston only near the end of its downward stroke, to smoothly reverse the piston motion, limit downward force on the patient at the end of the stroke, and avoid a downward pulse due to the momentum of the downwardly-moving piston. A stop (90, 92) is latchable in an inward position to allow reduction in the piston stroke by engaging an outward flange (56) on the piston before the piston has moved fully downward.

Abstract: A real time image is created of blood circulation deep (e.g. a plurality of millimeters) below the surface of living tissue to aid in evaluating a patient. A first beam (26) of circularly polarized light is directed forwardly (F) against an outer surface (14) of the tissue, the circularly polarized beam penetrating into a deep region (12) of the tissue. Along shallow depths (42), light of the first beam is scattered a minimum amount from tissue and a portion of such light that passes rearwardly and out of the tissue remains polarized. Along greater depths (12), light of the first beam is scattered much more and becomes depolarized, and a portion of that deep light travels rearwardly (R) and back illuminates the overlying tissue. Light emerging from the outer surface of the tissue and traveling rearwardly, which constitutes a second beam (36), is passed through a depolarizing filter (24) that passes primarily only unpolarized light, so light from a shallow depth is largely blocked.

Abstract: Apparatus for compressing the chest of a patient to stimulate blood circulation, includes a torso wrap (32) that has a back portion (40) lying at the back of the patient's chest and a front portion (42) lying at the front of the patient's chest, and includes a compressor assembly with an actuator (16) having a pressing member (12) that can apply a series of force pulses to the sternum of the patient to stimulate blood circulation. The actuator is energized by pressured fluid, with a controlled pressured fluid source (20) connected by an elongated flexible hose (24) to the actuator so the pressured fluid source and a control (22) can lie on the ground and only the actuator lies on the torso wrap. The actuator includes a cylinder (66) and a plurality of telescoping piston parts (64, 66) to provide a long stroke in an actuator of small height. A stabilizer (150) that limits tilt of the actuator from the vertical, includes a saucer-shaped member that presses against the front of the patient.

Abstract: A method is provided for controlling an automatic external defibrillator without stopping CPR (primarily chest compressions). While chest compressions continue to be applied to the victim, the system differentiates between (1) a perfusing rhythm that has the capability of leading to a beating heart without a shock and (2) ventricular fibrillation (VF) which sometimes occurs in the presence of ventricular tachycardia (VT), in which there is no capability for leading to a beating heart without a shock. Defibrillation shocks should be applied only when needed and that is in the presence of VF and sometimes in the presence of VT. Electrocardiographic (ECG or EKG) signals obtained from electrodes applied to the patient's chest are analyzed so that the presence of a QRS signal characteristic of a rhythm which has the potential of supporting a beating heart, or the absence of a QRS signal which indicates ventricular fibrillation, may be detected in the presence of artifacts resulting from chest compressions.

Abstract: The condition of a patient who has signs of cardiopulmonary arrest, is evaluated by applying a pair of electrodes (12, 14) to the chest of the patient and passing a low level of alternating current through the patient to detect changes in transthoracic impedance which represent cardiopulmonary activity of the patient. An analyzing circuit determines the average frequency of those signals (40) representing heartbeat rate impedance and determines the average frequency of signals (42) representing breathing of the patient. When the heart rate is below about 20 beats per minutes, the respiratory rate is below about 4 breaths per minute, and cardiac and respiratory impedances are below 0.01 ohms, this indicates cardiac arrest of the patient and signifies that CPR (cardiopulmonary resuscitation) should start.

Abstract: A device is provided for assessing impairment of blood circulation in a patient, such as that in perfusion failure, by measurement of blood flow adjacent a mucosal surface accessible by a mouth or nose and connecting with the gastrointestinal tract or upper respiratory/digestive tract of a patient. The device includes a blood-flow sensor adapted to be positioned adjacent a mucosal surface with a patient's body and measuring blood flow in adjacent tissue and a PCO2 sensor adapted to be positioned adjacent the mucosal surface and measuring PCO2. In addition a pH sensor may be used in combination with the blood flow determination. The invention affords rapid measurement and detection of perfusion failure.

Abstract: Methods, formulations and kits are described for resuscitating a patient suffering from cardiac arrest, for enhancing the efficacy of cardiopulmonary resuscitation, for treating post-resuscitation hypotension, and for reducing the incidence of ventricular arrhythmias and myocardial dysfunction in a patient following cardiopulmonary resuscitation. Prior methods and agents often cause inotropic or chronotropic effects, which can lead to undesirable post-resuscitation myocardial dysfunction. The invention comprises administering a therapeutically effective amount of an &agr;2-receptor agonist that does not cross the blood-brain barrier, such as &agr;-methylnorepinephrine, to enhance cardiopulmonary resuscitation.

Abstract: Apparatus is provided for use during the treatment of a victim undergoing cardiac arrest, to facilitate treatment by chest compression as well as by shocks from an automatic defribrillator. The apparatus includes a sheet of dielectric material that covers much of the victim to electrically isolate a rescuer who is performing chest compressions, from the victim to whom electric shocks are being delivered. Defribrillator electrodes are mounted on the lower face of the sheet and are connected to the defribillator. The sheet extends down along the sides of the victim to isolate the rescuer, who is either standing or kneeling beside the victim to apply chest compressions.

Abstract: The condition of a patient who has signs of cardiopulmonary arrest, is evaluated by applying a pair of electrodes (12,14) to the chest of the patient and passing a low level of alternating current through the patient to detect changes in transthoracic impedance which represent cardiopulmonary activity of the patient. An analyzing circuit determines the average frequency of those signals (40) representing heartbeat rate impedance and determines the average frequency of signals (42) representing breathing of the patient. When the heart rate is below about 20 beats per minutes, the respiratory rate is below about 4 breaths per minute, and cardiac and respiratory impedances are below 0.01 ohms, this indicates cardiac arrest of the patient and signifies that CPR (cardiopulmonary resuscitation) should start.

Abstract: Apparatus is provided for treatment of a victim to reverse cardiac arrest by chest compression and by electrical defibrillation through electrodes applied to the chest area of the victim. The apparatus includes a dielectric layer which is placed on the victim to electrically isolate the rescuer who is performing chest compressions. The protective sheet includes a layer of electrically conductive material sandwiched between two dielectric layers to electrically isolate the rescuer. The sandwiched conductive layer is connected to a location on the body of the victim that is spaced a plurality of inches from each of the electrodes.

Abstract: Methods and devices are provided for assessing impairment of blood circulation in a patient, such as that in perfusion failure, by measurement of blood flow in the gastrointestinal tract or upper respiratory/digestive tract of the patient. The method comprises introducing a blood-flow sensor into the gastrointestinal tract or the upper respiratory/digestive tract of a patient, placing the sensor adjacent a mucosal surface therein, and measuring blood flow in adjacent tissue to determine blood flow in that tissue. The method may also involve measurement of PCO2 and/or pH in combination with the blood flow determination. The invention affords rapid measurement and detection of perfusion failure.

Abstract: Methods and devices are provided for assessing impairment of blood circulation in a patient, such as that in perfusion failure, by measurement of blood flow in the gastrointestinal tract or upper respiratory/digestive tract of the patient. The method comprises introducing a blood-flow sensor into the gastrointestinal tract or the upper respiratory/digestive tract of a patient, placing the sensor adjacent a mucosal surface therein, and measuring blood flow in adjacent tissue to determine blood flow in that tissue. The method may also involve measurement of PCO2 and/or pH in combination with the blood flow determination. The invention affords rapid measurement and detection of perfusion failure.

Abstract: Methods and devices are provided for assessing impairment of blood circulation in a patient, such as that in perfusion failure, by measurement of pCO2 (partial pressure of carbon dioxide) in the upper digestive and/or respiratory tract of the patient. The method comprises introducing a carbon dioxide sensor into the upper digestive and/or respiratory tract of a patient, without passing the sensor down through or beyond the patient's epiglottis. Specifically, a carbon dioxide sensor is placed adjacent a mucosal surface within the upper digestive and/or respiratory tract, preferably within the patient's mouth or inside the patient's nose. By avoiding passage through the mouth into the throat and esophagus, discomfort is substantially avoided and the potential for injury minimized.