© 2005 American Thoracic Society
Some Methodological Considerations Pertaining to Sniff Nasal Inspiratory Pressure (SNIP)From the Authors:I thank Dr. Fitting for his interest in our study (1). The purpose of the work was to examine how changes, over time, in SNIP may be related to prognosis. The study showed that the lower the SNIP value, the worse the survival in patients with ALS. We are in debt to the correspondent and others for their prior publications in the field as their work prompted the current study. Prior to commencement of the study we were unable to purchase a device to measure SNIP. We adapted a device similar to those described in the literature. Our aim was to study patients with ALS, and so our preliminary work allowed us to use various types of nasal padding and occlusion materials to suit the nares of a large number of patients, as described in the paper. We noted that the volitional effort made by the patient was a very important variable in the testing. As patients with advanced ALS tend to make poor efforts and often need encouragement, we noted that occlusion of the contralateral nares permitted us to detect nasal alae contraction and so permitted us to encourage maximal inspiratory efforts. This served as a means of feedback and encouragement. While this may overestimate the inspiratory pressure by a small degree in normal individuals, patients with ALS almost invariably have weak bulbar muscles, and so the spurious increase is in all probability insignificant. We reported what we considered to be meaningful changes in SNIP of 10 cm H2O. SNEP refers to "snort" nasal expiratory pressure. We hoped that the test may become more widely used if the acronym SNIF (for the maneuver) was adapted.
Beaumont Hospital, Dublin, Ireland FOOTNOTES Conflict of Interest Statement: R.C. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript. REFERENCES
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