CPR volume exchanger valve system with safety feature and methods
View Patent ↗A method for regulating gas flows into and out of a patient includes repetitively forcing respiratory gases out of the lungs. Respiratory gases are prevented from entering back into the lungs during a time between when respiratory gases are forced out of the lungs. Periodically, an oxygen-containing gas is supplied to the lungs.
1. A method to perform cardiopulmonary resuscitation in a patient in cardiac arrest, the method comprising:
providing a valve system comprising a pressure-responsive valve that is configured to be coupled to the patient's airway;
providing at least one timing light that is configured to help guide a rescuer in performing a desired compression rate when repetitively compressing the chest;
providing instructions to repetitively compress the chest and permit the chest to recoil a rate of about 60 to about 120 times/min by following a cadence of the timing light;
providing instructions as to a proper depth for each chest compression;
wherein with each compression a volume of respiratory gas is expelled from the lungs;
wherein for a plurality of chest recoils, respiratory gases are prevented from returning to the lungs with the valve system such that over successive chest compression/chest recoil cycles there is a successive decrease in respiratory gases within the lungs thereby allowing more blood to enter the thoracic space; and
providing instructions to periodically actively expand the lungs with an oxygen-containing gas.
2. A method as in claim 1 , wherein the step of permitting the chest to recoil comprises permitting the chest to recoil by its own resilience or by actively pulling upward on the chest to achieve complete chest wall recoil.
3. A method as in claim 1 , wherein during the chest recoil, intracranial pressures are decreased more rapidly and to a lower value thereby further increasing the duration and magnitude of cerebral perfusion pressure, and further comprising providing a pressure-responsive one way valve that opens to permit air to flow into the lungs through the valve if the patient begins to breathe.
4. A method as in claim 1 , wherein the volume of respiratory gas expelled over a series of chest compression/recoil cycles is in the range from about 1 to about 15 cc/kg.
5. A method as in claim 1 , further comprising expelling the volume of respiratory gas from the chest against a low level of fixed or variable resistance that is in the range from about 0 to about 10 cm H2O.
6. A method as in claim 1 , further comprising providing visual or audible instructions to a rescuer as to a desired compression or ventilation rate.
7. A method as in claim 1 , further comprising measuring patient gas volumes or airway pressures, and using a controller having a memory and a computer processor to estimate the rate and depth of chest compressions by evaluating variations in the amount of gasses delivered or airway pressure produced by positive-pressure ventilations to the amount of gasses expelled or airway pressures produced during chest compressions or chest recoil.
8. A method as in claim 1 , wherein respiratory gases are prevented from reaching the lungs until about 2 to about 6 compressions have been performed.
9. A method to perform cardiopulmonary resuscitation in a patient in cardiac arrest, the method comprising:
providing a valve system comprising a pressure-responsive valve that is configured to be coupled to the patient's airway;
providing at least one sensor to sense at least one of: ventilation rate, degree of chest compression or rate of chest compression;
providing instructions to repetitively compress the chest and permit the chest to recoil a rate of about 60 to about 120 times/min;
providing instructions as to a proper depth for each chest compression;
wherein with each compression a volume of respiratory gas is expelled from the lungs;
wherein for a plurality of chest recoils, respiratory gases are prevented from returning to the lungs such that over successive chest compression/chest recoil cycles there is a successive decrease in respiratory gases within the lungs thereby allowing more blood to enter the thoracic space;
providing instructions to periodically actively expand the lungs with an oxygen-containing gas; and
wherein the sensor is configured to provide feedback to a rescuer as to whether the ventilation rate, degree of chest compression and/or rate of chest compression are proper.