Surgery – Respiratory method or device – Means for supplying respiratory gas under positive pressure
Reexamination Certificate
1998-12-10
2001-07-03
Lewis, Aaron J. (Department: 3761)
Surgery
Respiratory method or device
Means for supplying respiratory gas under positive pressure
C128S205140, C128S205150, C128S205160, C128S205170
Reexamination Certificate
active
06253767
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a gas concentrator, and, more particularly, to an enhanced oxygen/gas concentrator utilizing a unique oxygen/gas concentration device providing instantaneous delivery of rich oxygen/gas concentrations to a patient.
2. Description of the Background Art
Resuscitation devices are used to temporarily emulate a patient's natural breathing. Resuscitation generally refers to externally applied assistance to supplement or restore an individual's respiratory activity. Resuscitation devices force oxygen-air mixtures through a patient's airway system to the lungs at staged intervals, while intermittently applying pressure to the patient's chest cavity inducing exhalation. “Squeeze bag” or “bag-valve-mask” resuscitators make use of some type of manually compressible and self-restoring bag in fluid communication with a face-mask. The operation of prior art resuscitation devices can be broken down into a two step process. First, the mask is applied to the face of a patient while manually squeezing the bag to force air from the bag through the mask and into the patient's lungs. Second, releasing the manually applied pressure from the bag and removing the mask from the patient's face to permit escape of air from the patient's lungs. During this step, the bag would self-inflate with atmospheric air through the mask. The bag would then remain in its restored condition until the next cycle, repeating as necessary. A squeeze bag resuscitator allows a trained person administering treatment to control the quantity and rate of air forced into the patient's lungs.
Squeeze bag resuscitators soon incorporated various refinements. To increase portability and facilitate use by a single person, resilient squeeze bags were adapted to be conveniently held in one hand with the face-masks attached directly to the frontal extremities of the bags. A one-way check valve in fluid communication with the interior of the bag and the atmosphere was introduced to permit refilling of the bag with fresh air during its restoration phase without removing the mask from the face of the patient. Additionally, the patient non-rebreathing valve assembly emerged. The assembly is located between the bag and the mask and permits fresh air to move from the bag into the mask during the squeeze phase, but vents to the atmosphere air returned to the mask from the patient's lungs during the bag restoration phase, preventing passage of the expired air into the bag from which it would be forced back into the patients lungs or “rebreathed” during the next squeeze phase.
During the course of development of squeeze bag type resuscitators, it was recognized that it would be desirable to administer pure oxygen, or at least oxygen enriched air, rather than merely atmospheric air, in treating some resuscitation patients. Accordingly, the development of a practical means for introducing oxygen into the squeeze bag initially entailed providing “oxygen enrichment” for the air drawn into the squeeze bag from the atmosphere during the restoration phase of the bag cycle. A common method for oxygen enrichment is to provide an elongate tube of relatively large diameter having one end in fluid communication with the fill valve opening of the bag and the other end exposed to the atmosphere, together with a considerably smaller tube extending into the larger tube and coupled with a pressurized oxygen source for continuously releasing oxygen into the air entering and accumulating within the large tube from the atmosphere. Such devices are referred to as “oxygen accumulators” and are effective to introduce air-oxygen mixtures into the bag during the restoration phase of its cycle, without significantly increasing the pressure within the bag. Examples of these and other oxygen accumulator resuscitators may be found in U.S. Pat. Nos. 4,501,271, 4,774,941, 4,821,713, 5,067,487, 5,109,840, 5,140,982 and 5,279,289. A shortcoming of resuscitators of this type is that the ambient air can dilute the concentration of the continuously flowing oxygen gas.
In the oxygen accumulator resuscitators described in U.S. Pat. Nos. 4,821,713, 5,067,487 and 5,140,982, two discrete, sequentially operable valves are provided to deliver the air/oxygen mixture, first into the tubular member and then into the face mask. Each valve has a comparatively high spring bias. The first valve can only be opened by releasing the squeeze bag from a compressed state, while the second valve is opened only by squeezing the bag. That is, the patient's spontaneous inspiratory efforts are not capable of operating the valves. This situation is exacerbated by the presence of the mask expiration port that is in direct fluid communication with the atmosphere which assures that insufficient negative inspiratory pressure can be developed in the mask to effect valve actuation.
Furthermore, the advent of the oxygen accumulator squeeze bag resuscitator did not satisfy the need for being able to administer substantially pure oxygen to patients under certain relatively frequently occurring high oxygen demand circumstances, such as resuscitation responsive to cardiac distress or like conditions. The invention disclosed in U.S. Pat. No. 3,796,216 attempts to administer essentially pure oxygen to a patient using a squeeze bag resuscitator. The apparatus included a body member, a squeeze bag, an oxygen inlet, a flapper valve and a face mask. The body member comprises a tubular portion to which the mouth of the squeeze bag is connected. The face mask is joined to the tubular member generally opposite the squeeze bag and an inlet adapted to be connected to a source of breathing gas, such as oxygen, is provided in the tubular member between the squeeze bag and the face mask. The flapper valve regulates passage of oxygen from the squeeze bag to the face mask.
Comparatively, the squeeze bag disclosed in U.S. Pat. No. 3,796,216 is not self-restoring, but is pliable and intended to be continuously inflated with oxygen. When the bag is sufficiently inflated and it is desired to administer oxygen to the patient, the administrator squeezes the bag to increase the pressure in the tubular member to a level sufficient to cause the flapper valve to expose a mask inhalation port and cover a mask exhalation port whereby the oxygen flows into the mask and then to the patient. Once the bag contents are depleted, i.e., the pressure in the body member is insufficient to overcome the bias of the flapper valve, the valve returns to its normal position covering the inhalation port and exposing the exhalation port. At this time, the patient exhales, his expiratory gases pass through the exhalation port and then the bag reinflates. This process is repeated until the patient breathes normally.
However, this type of system is incapable of dispensing pressurized atmospheric air in the event of failure or depletion of the pressurized oxygen supply. Specifically, even if the gas source were disconnected from the gas inlet thereby exposing the inlet to the atmosphere, the squeeze bag is not self-restoring. That is, the squeeze bag cannot create either the negative pressure required to draw air into the inlet or the positive pressure to expel the air. U.S. Pat. Nos. 2,399,643, 2,834,339, 3,196,866, 3,316,903, 3,473,529, 4,037,595, 4,077,404, 4,088,131, and 4,121,580 describe self-distending squeeze bag or similar resuscitators capable of administering air, oxygen or air-oxygen mixtures upon compressing the squeeze bag. Gas flow to and from the patient is effected by the opening and closing of at least one, and usually two or more, spring-biased check valves, flap valves or combinations of both. The resuscitators disclosed in U.S. Pat. Nos. 3,196,866 and 3,316,903 operate such that during expansion of the squeeze bag, the oxygen being supplied to the bag will always be mixed with atmospheric air because the resuscitator valve assembly includes ports in communication with the atmosphere and the interior of the bag, sai
Holland & Knight LLP
Lewis Aaron J.
Patel Mital
LandOfFree
Gas concentrator does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Gas concentrator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gas concentrator will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2457443