Surgery – Respiratory method or device – Means for supplying respiratory gas under positive pressure
Reexamination Certificate
2002-08-27
2004-11-09
Bennett, Henry (Department: 3743)
Surgery
Respiratory method or device
Means for supplying respiratory gas under positive pressure
C128S204180, C128S204230, C128S204210
Reexamination Certificate
active
06814076
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to mechanical ventilation systems. More particularly, it relates to mechanical respiratory assistance by ambient pressure control ventilation in a close chamber.
BACKGROUND OF THE INVENTION
Assisted or artificial respiratory actions on patients are often used in medical practice. Two types of ventilation methods are generally used: positive pressure ventilation, when periodic positive airway pressure is applied on patients airways and lungs, and negative pressure ventilation (iron lungs) when the patient's chest region is enclosed by an enclosure in which subatmospheric pressure is applied periodically.
Those main traditional methods of mechanical respiratory assistance such as positive airway pressure ventilation as well as “iron-lungs” are known to have a lot of physiological adverse effects, technical disadvantages and pitfalls. The main disadvantages of positive pressure methods of ventilation stem from the need to inflate the gas mixture into the patient's airway and lungs with such a positive pressure that its range is comparable with right and left heart ventricles filling pressures. This can interfere with the venous blood return to the heart that may result in hemodynamic deterioration, especially in patients that suffer from hypovolemia, compromised cardiac function, lung and chest problems and shock. Furthermore, patient's suffering from these diseases are already in poor medical condition, and their body is very likely not to withstand the strenuous procedure. Positive pressure ventilation may also result in barotrauma of airway and lungs with possible development of life threatening complications. Long time exposure to positive pressure ventilation may result also in the development of lung atelectasis and/or secondary infection, which is directly related to the duration of the mechanical positive pressure ventilation. Positive pressure ventilation also requires the inflation of endotracheal tube balloon with such pressures that on one hand, it establishes airway sealing, but on the other hand it may result in severe damage to the tracheal mucosa and tracheal wall, potentially leading to very dangerous complications, such as tracheal wall and great mediastinal vessels rupture.
Negative pressure ventilation, as opposed to positive pressure ventilation, is free from problems related to venous return and cardiovascular deterioration as well as barotrauma development. There are problems that arise from the employment of negative pressure ventilation. The need to accommodate the patient's body in an enclosure requires the use of sealing means that are very difficult to fit on the patient's neck, chest and abdomen. It is especially difficult in pediatric population or in uncooperative patients as well as during prolonged mechanical ventilation. Negative pressure ventilators are very difficult to use in weaning from mechanical ventilation.
Improvements of mechanical respiratory systems are known in the art. An example of such system that encloses the chest region is disclosed in U.S. Pat. No. 4,815,452 “VENTILATOR APPARATUS AND FLUID CONTROL VALVE”, filed in 1988 by Z. Hayek. One aspect of the invention provides a patient enclosure for ventilator apparatus comprising a base member and a liftable cover member which in an operative position defines a patient receiving chamber having at least one aperture in the cover member for accommodating a portion of the patient's body, the or each such aperture in the cover member being open along an edge of the cover member which overlies the base member in the operative position and containing a seal member for forming a substantially airtight seal in use between the cover member and the patient's body and the base member, wherein the seal member takes the form of a flexible curtain having a free edge overlying the base member and means for tensioning a portion of the curtain to cause the curtain to seal against the base member and the patient's body.
Another enclosure for ventilation is disclosed in EP patent No. 0379049 “CHEST ENCLOSURE FOR VENTILATORS” published in 1990 by Z. Hayek. This chest enclosure is used for introducing assisted ventilation for the lungs of a patient, when combined with an air oscillator. The chest enclosure comprises a stiff but flexible plastic tunnel member adapted to cover the chest, provided at its upper and its lower end with an air-impermeable flexible cushion, a band of flexible material extending from along the entire lateral edges of the tunnel, said bands extending to behind the back of the patient in an overlapping relationship, means being provided for the attachment of the bands with each other, an air passageway being provided into the enclosure for connection to an air oscillator.
Ventilators of this type provide an apparatus in which at least the patient's head protrudes from the enclosure. In order to enable pressure changes in the enclosure, sealing the enclosure from the surrounding is necessary. Sealing the enclosure promotes problems and can also delay the commencing of assisted respiration, which potentially may cause damage to the patient.
The use of a pressurized container in which the whole body is enclosed was developed for blood oxygenation in premature neonates. The method is disclosed in U.S. Pat. No. 5,582,574 “HYPERBARIC INCUBATION METHOD” filed in 1995 by F. S. Cramer. This pressurized container is filled with pure oxygen. The apparatus, and the method of treatment provided thereby, are able to deliver oxygen to the blood of an enclosed premature neonate by means of directly diffusing molecular oxygen through the unusually permeable skin of such infants. Hyperbaric pressure, i.e., pressure substantially above one atmosphere absolute (ATA), preferably at least two ATA, is maintained in the container, which facilitates the transcutaneous delivery of oxygen to the blood. Means are included for protecting the eyes of the neonate and for performing physiological ventilation of the lungs thereof. The provision of normal tissue oxygen tensions facilitates the neurological development of the infant, thereby enhancing its long-term quality of life.
BRIEF DESCRIPTION OF THE INVENTION
It is a purpose of the present invention to provide new ambient pressure control ventilation apparatus for mechanical ventilation of a patient. The patient is placed inside a sealed chamber wherein within that chamber periodic changes of pressure are applied.
It is another purpose of the present invention to provide an ambient pressure control ventilation apparatus for mechanical ventilation applicable in cases were traditional mechanical ventilation fails. These cases include among others patients with hemodynamic deterioration such as hypovolemia, compromised cardiac function, marginal cases of respiratory distress syndrome, chest, airway and lung trauma and bleeding, and asthmatic attack.
Yet another purpose of the present invention is to provide an ambient pressure control ventilation apparatus for home ventilation which is safer for users and provide more comfort conditions for patients suffering from chronic respiratory failure who need negative or positive pressure ventilators for home use, especially in pediatric and uncooperative populations.
Still another purpose of the present invention is to provide an ambient pressure control ventilation apparatus for weaning from mechanical ventilation.
It is another purpose of the present invention to provide an ambient pressure control ventilation apparatus for patients with chest, neck and abdomen deformity, scars, chronic infections, burns etc., which make positive pressure ventilation difficult and negative pressure ventilation impossible.
Yet another purpose of the present invention is to provide an ambient pressure control ventilation apparatus for the treatment of patients suffering from congestive heart failure. The outpatient, home or intermittent overnight use of the novel apparatus enables decreasing at least part of the patient's medication i
Shusterman Mark
Shusterman Taly
Bennett Henry
Dippert William H.
Patel Mital
Reed Smith LLP
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