Surgery – Miscellaneous
Reexamination Certificate
2001-03-01
2003-05-27
Winakur, Eric F. (Department: 3736)
Surgery
Miscellaneous
C600S529000
Reexamination Certificate
active
06568397
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates in general to the field of speech pathology, and is directed to determining whether a patient is at risk for one or more abnormal physiological conditions, including but not limited to oral or pharyngeal dysphagia, and pneumonia. In particular, the present invention is directed to an enhancement to the invention disclosed in the above-referenced '404 application, that involves the addition of a contrast substance to the aerosol chemostimulant, so as to allow fluoroscopic observation of the patient's (larynx) response, and facilitate a medical practitioner's visual monitoring of the patient's airway during the aerosol application of the chemostimulant.
BACKGROUND OF THE INVENTION
As described in the above-referenced '404 application, the conventional technique employed by speech pathologists for clinically identifying patients at risk for aspiration has involved the evaluation of a patient's swallow. A normal human swallow can be separated into four phases: 1)—oral preparation, 2)—the oral phase, 3)—the pharyngeal phase, and 4)—the esophageal phase. Patients who have suffered a stroke, traumatic brain injury or neuromuscular disorder (such as MS or ALS) have an increased risk of aspiration, and may have difficulty with either the oral phase, the pharyngeal phase or both, secondary to neurologic deficits.
Poor tongue movement in chewing or in the swallow can cause food to fall into the pharynx and into the open airway before the completion of the oral phase. A delay in triggering the pharyngeal swallowing reflex can result in food falling into the airway during the delay when the airway is open. Reduced peristalsis in the pharynx, whether unilateral or bilateral, will cause residue in the pharynx after the swallow that can fall or be inhaled into the airway. Laryngeal or cricopharyngeal dysfunction can lead to aspiration because of decreased airway protection during the swallow.
An abnormal human swallow is termed dysphagia. The oropharyngeal physiology involved in a normal swallow is very complicated, and many different neurological disturbances can disrupt normal swallowing and can cause aspiration of food material, liquid or solid, into the lungs, leading to increased morbidity in hospitalized patients and possible pneumonia. See, for example, the article by Jeri Logemann, entitled: “Swallowing Physiology and Pathophysiology,” Otolaryngologic Clinics of North America, Vol. 21, No. 4, November 1988, and the article by L. Kaha et. al., entitled: “Medical Complications During Stroke Rehabilitation, Stroke Vol. 26, No. 6, June 1995.
Speech pathologists have tried many procedures to detect or predict aspiration in patients with neurological deficits. Although the standard bedside swallow exam to screen patients is beneficial for evaluating patients at risk for oral or pharyngeal dysphagia, studies have shown that, when compared to a modified barium swallow (MBS) videofluoroscopic examination, it is neither very specific nor sensitive in detecting aspiration. (The MBS test customarily involves having the patient ingest a volume of barium in a semi-solid or liquid form. Through fluoroscopy, the travel path of the swallowed barium may be observed by a medical practitioner to determine whether any quantity has been aspirated—which could lead to acute respiratory syndrome or pneumonia.) See, for example, the article by Mark Splaingard et. al. entitled: “Aspiration in Rehabilitation Patients: ideofluoroscopy vs. Bedside Clinical Assessment; Archives of Physical Medicine and Rehabilitation, Vol. 69, August, 1988, and the article by P. Linden, et. al., entitled” “The Probability of Correctly Predicting Subglottic Penetration from Clinical Observations”, Dysphagia, 8: pp 170-179, 1993.
As discussed in the above-referenced Logemann article, and also in an article entitled: “Aspiration of High-Density Barium Contrast Medium Causing Acute Pulmonary Inflammation—Report of Two Fatal Cases in Elderly Women with Disordered Swallowing,” by C, Gray et al, Clinical Radiology, Vol. 40, 397-400, 1989, videofluoroscopic evaluations are more costly than bedside evaluations and videofluoroscopy is not entirely without risk. Because of the poor predictability of bedside exams, the MBS is being used more and more with its increased reliability for diagnosing aspiration. Many studies using videofluoroscopy have tried to pinpoint the exact anatomical or neurological deficit causing the dysphagia, as well as what stage of the swallow is primarily affected in different disorders.
Patients with a head injury, stroke or other neuromuscular disorder can aspirate before, during, or after the swallow, and a high percentage can be silent aspirators. Unfortunately, these patients might not display any indication of aspiration during a clinical exam, but can be detected by the MBS, as discussed in the Logemann article and in an article by C. Lazurus et al, entitled: “Swallowing Disorder in Closed Head Trauma Patients,” Archives of Physical Medicine and Rehabilitation, Vol. 68, February, 1987, an article by J. Logemann, entitled: “Effects of Aging on the Swallowing Mechanism,” Otolaryngologic Clinics of North America, Vol. 23, No. 6, December 1990, and an article by M. DeVito et. al., entitled: “Swallowing Disorders in Patients with Prolonged Orotracheal Intubation or Tracheostomy Tubes,” Critical Care Medicine, Vol. 18, No. 12, 1990.
The bedside swallow exam that has been customarily performed by most speech pathologists evaluates history, respiratory status, level of responsiveness and an oral exam. The oral examination includes a detailed evaluation of the muscles of mastication, lips, tongue, palate, position in which the patient is tested, as well as swallowing evaluation. Sensation, various movements and strength are carefully evaluated. In the pharyngeal stage, the patient is tested for a dry swallow, thin liquid, thick liquid, pureed textures and solid textures.
A typical bedside exam looks for nasal regurgitation, discomfort or obstruction in the throat or multiple swallows, as well as any visible signs that may indicate risk for aspiration, gurgling, impaired vocal quality, and coughing. The bedside exam results are then analyzed to determine whether the patient should have an MBS study to evaluate swallowing physiology and to rule out aspiration. Although the bedside exam is very thorough, and can identify patients who are at risk for or have dysphagia, it is not effective in determining which patients will aspirate.
In addition to the foregoing, speech pathologists have historically had difficulty studying the sensory afferents of the larynx involved in airway protection. As described in an article by J. Widdicombe et al, entitled: “Upper Airway Reflex Control,” Annual New York Academy of Science, Vol. 533, 252-261, 1988, the sensory afferents for general coughing travel the internal branch of the superior laryngeal nerve. A patient may have a voluntary cough present with the efferent motor system intact, but not have any sensation on the larynx secondary to the afferents becoming completely or partially affected, which would be indicative of risk for silent aspiration.
Although an MBS test is of value to patients that silently aspirate, it is difficult to decide which patients should have an MBS test. Not all patients with a closed head injury or a stroke will aspirate. Moreover, it is not economically realistic to employ an MBS test to evaluate all patients with neurologic deficits for aspiration.
Fortunately, the chemostimulant-based, cough-invoking screening process described in the '404 application and its parent predecessors, referenced above, successfully overcomes shortcomings of such conventional processes that have attempted to detect aspiration in patients with neurological deficits. Referring to
FIG. 1
, pursuant to the invention disclosed in these applications, a patient
10
(wearing a nose clip
12
) is subjected to an chemostimulant-based, inhalation cough test. In this test, a prescribed quantity of a
Addington W. Robert
Miller Stuart P.
Stephens Robert E.
Allen Dyer Doppelt Milbrath & Gilchrist, P.A.
McCrosky David J
Pneumoflex Systems L.L.C.
Winakur Eric F.
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