Surgery – Diagnostic testing – Respiratory
Reexamination Certificate
2001-07-02
2004-03-23
Nasser, Robert L. (Department: 3736)
Surgery
Diagnostic testing
Respiratory
C600S532000
Reexamination Certificate
active
06709401
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to medical methods, systems, and kits. More particularly, the present invention relates to methods and apparatus for effecting lung volume reduction by aspirating isolated segments of lung tissue.
Chronic obstructive pulmonary disease is a significant medical problem affecting 16 million people or about 6% of the U.S. population. Specific diseases in this group include chronic obstructive bronchitis, asthmatic (without bronchitis), and emphysema. While a number of therapeutic interventions are used and have been proposed, none are completely effective, and chronic obstructive pulmonary disease remains the fourth most common cause of death in the United States. Thus, improved and alternative treatments and therapies would be of significant benefit.
Of particular interest to the present invention, lung function in patients suffering from chronic obstructive pulmonary disease can be improved by reducing the effective lung volume, typically by resecting diseased portions of the lung. Resection of diseased portions of the lungs both promotes expansion of the non-diseased regions of the lung and decreases the portion of inhaled air which goes into the lungs but is unable to transfer oxygen to the blood. Lung reduction is conventionally performed in open chest or thoracoscopic procedures where the lung is resected, typically using stapling devices having integral cutting blades.
While effective in many cases, conventional lung reduction surgery is significantly traumatic to the patient, even when thoracoscopic procedures are employed. Such procedures often result in the unintentional removal of healthy lung tissue, and frequently leave perforations or other discontinuities in the lung which result in air leakage from the remaining lung. Even technically successful procedures can cause respiratory failure, pneumonia, death, and many older or compromised patients are not even candidates for these procedures. For these reasons, it would be desirable to provide improved methods, systems, and kits for performing lung volume reduction which overcome at least some of the shortcomings noted above.
2. Description of the Background Art
WO 99/01076 describes devices and methods for reducing the size of lung tissue by applying heat energy to shrink collagen in the tissue. In one embodiment, air may be removed from a bleb in the lung to reduce its size. Air passages to the bleb may then be sealed, e.g., by heating, to fix the size of the bleb. WO 98/49191 describes a plug-like device for placement in a lung air passage to isolate a region of lung tissue, where air is not removed from the tissue prior to plugging. WO 98/48706 describes the use of surfactants in lung lavage for treating respiratory distress syndrome.
Patents and applications relating to lung access, diagnosis, and treatment include U.S. Pat. Nos. 5,752,921; 5,707,352; 5,682,880; 5,660,175; 5,653,231; 5,645,519; 5,642,730; 5,598,840; 5,499,625; 5,477,851; 5,361,753; 5,331,947; 5,309,903; 5,285,778; 5,146,916; 5,143,062; 5,056,529; 4,976,710; 4,955,375; 4,961,738; 4,958,932; 4,949,716; 4,896,941; 4,862,874; 4,850,371; 4,846,153; 4,819,664; 4,784,133; 4,742,819; 4,716,896; 4,567,882; 4,453,545; 4,468,216; 4,327,721; 4,327,720; 4,041,936; 3,913,568 3,866,599; 3,776,222; 3,677,262; 3,669,098; 3,498,286; 3,322,126; WO 95/33506, and WO 92/10971.
Lung volume reduction surgery is described in many publications, including Becker et al. (1998) Am. J. Respir. Crit. Care Med. 157:1593-1599; Criner et al. (1998) Am. J. Respir. Crit. Care Med. 157:1578-1585; Kotloff et al. (1998) Chest 113:890-895; and Ojo et al. (1997) Chest 112:1494-1500.
The use of mucolytic agents for clearing lung obstructions is described in Sclafani (1999) AARC Times, January, 69-97. Use of a balloon-cuffed bronchofiberscope to reinflate a lung segment suffering from refractory atelectasis is described in Harada et al. (1983) Chest 84:725-728.
SUMMARY OF THE INVENTION
The present invention provides improved methods, systems, and kits for performing lung volume reduction in patients suffering from chronic obstructive pulmonary disease or other conditions where isolation of a lung segment or reduction of lung volume is desired. The methods are minimally invasive with instruments being introduced through the mouth (endotracheally) and/or in some cases through the chest, (e.g., thoracoscopically), and rely on isolating the target lung tissue segment from other regions of the lung. Isolation is usually achieved by introducing an isolation/access catheter endotracheally to the air passages of a lung. By positioning a distal end of an isolation/access catheter within an air passage which opens into a target lung tissue segment, the segment may be isolated by occluding the air passage, typically by inflating an occlusion balloon or other structure on the catheter within the air passage. The target lung tissue segment may then be collapsed by aspirating air (and any other gases or liquids that may have been introduced) from the segment, typically through a lumen in the isolation/access catheter. Optionally, the air passage may then be sealed, for example by deploying a plug within the air passage. Suitable plugs include swellable collagen matrices which hydrate and expand within the air passage so that they fully occlude the passage. Other sealing methods include the use of tissue adhesives, such as fibrin glues, cyanoacrylate, etc.; the use of occlusive balloons; the use of self-expanding meshes, coils, and other occlusive structures; the use of energy-induced tissue fusion, such as radiofrequency tissue closure; and the like.
In a first particular aspect of the methods of the present invention, air flow through and from the target lung tissue segment will be enhanced prior to aspiration of the segment. It is an objective of the present invention to aspirate and reduce the volume of the lung tissue segment as completely as possible. In one instance, obstructions to gas flow within the target tissue segment are reduced prior to or during aspiration of the segment. Mucus and other obstructions within the target lung tissue segment (which is diseased and frequently subject to blockages) will interfere with substantially complete aspiration of the segment unless removed, disrupted, or otherwise addressed. In a second instance, where a lack of lung surfactant is a cause of the impeded air flow, the present invention will provide for administering a suitable surfactant prior to or during aspiration of the target lung tissue segment.
In a first specific instance, the present invention reduces gas flow obstructions by inflating the lung tissue segment to a pressure higher than normal respiratory inflation pressures. Optionally, portions or segments of the lung adjacent to the target lung segments may be partially deflated or under-ventilated at the same time that the target segment is being inflated at a higher than normal pressure. For example, airflow into adjacent lung segments can be partially blocked to lower pressure in those segments, causing those segments to partially collapse. In a specific instance, a balloon can be used to partially block the bronchus of the lung with the target lung tissue segment.
Usually, the isolated lung tissue segment will be inflated to a pressure in the range from 60 cm H
2
O to 200 cm H
2
O, preferably in the range from 100 cm H
2
O to 150 cm H
2
O, usually during the administration of general anesthesia (positive pressure ventilation). If a local anesthesia is being used, the pressure will usually be in the range from 10 cm H
2
O to 100 cm H
2
O, preferably from 30 cm H
2
O to 60 cm H
2
O. The duration of such “over inflation” will typically be in the range from one second to 600 seconds, preferably being in the range from 5 seconds to 60 seconds. Such lung inflation may be repeated more than one time. For example, the lung inflation may be carried out by inflating the isolated lung tissue segment in a pulsatile fashion. Over inflation will usually be perfo
Kotmel Robert
Perkins Rodney A.
Soltesz Peter P.
Nasser Robert L.
Pulmonx
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