Sniff Test PRINT
I. Equipment
a. Lead ruler (taped to the center of the table, under the cushion)
II. Personnel
a. Radiologist/RA
i. Responsible for imaging
ii. Gives breathing instructions
b. Hospital Technologist
i. Documents patient history and pregnancy status prior to exam
ii. Reviews order with RA/radiologist
iii. Assists the radiologist or RA during procedure
iv. Provides patient and floor nurse with aftercare instructions
III. Procedure
a. With the patient either standing (preferred) or supine, perform AP fluoroscopy of the diaphragm at rest
b. Have the patient take a deep breath in and blow all the air out (fluoro loop store or take spot images at peak inspiration and peak expiration)
c. Repeat bilaterally
d. Instruct patient to take a few quick breaths in through nose (SNIFF) causing rapid inspiration (fluoro loop store if possible)
e. If patient is able to stand, repeat sniffing in the lateral projection to evaluate posterior hemidiaphragms
IV. Required Images
a. Fluoro loop store bilateral hemidiaphragms
i. Deep inspiration
ii. Complete expiration
iii. Sniffing
V. Documentation
a. Measure inferior hemi diaphragmatic excursion bilaterally (document #cm of movement)
b. Document paradoxical motion
VI. Special Considerations
a. Ventilator dependence
i. Respiratory therapist to assist
ii. Observe motion of the diaphragm with the ventilator attached
iii. With ventilator disconnected- record a few spontaneous deep breaths before resuming mechanical ventilation
iv. Do not attempt sniffing or lateral views
b. Tracheostomy (able to breath without ventilator)
i. Patient may use a finger to partially occlude tracheostomy tube during forceful inspiration to replicate sniffing
https://pubs.rsna.org/doi/full/10.1148/rg.322115127
Sniff test | Radiology Reference Article | Radiopaedia.org