ASSESSMENT OF INSPIRATORY MUSCLE STRENGTH BY THE SNIFF NASAL INSPIRATORY PRESSURE

The measurement of oesophageal pressure during maximal sniffs (P-oes s niff) is useful to assess inspiratory muscle strength. The aim of this study was to develop a noninvasive test of inspiratory muscle strengt h based on the sniff manoeuvre. The sniff nasal inspiratory pressure ( SNIP) was measured through a plug occluding one nostril during sniffs performed through the contralateral nostril. In 10 normal subjects and in 12 patients with neuromuscular or skeletal disorders, the SNIP rel iably reflected the P-oes sniff. Nasal mucosa congestion was induced i n four normal subjects by nebulization of increasing doses of histamin e. The SNIP accurately reflected P-oes sniff when nasal congestion was moderate, but failed to do so when congestion was severe. Reference v alues of SNIP were established in a group of 160 healthy subjects aged 20-80 years. For both men and women, SNIP was negatively correlated w ith age, and was similar in the sitting and in the supine positions. S NIP was higher than maximal inspiratory pressure (P-1 max) in most sub jects, but the wide limits of agreement showed that these two methods are not interchangeable but complementary. The SNIP represents a usefu l noninvasive test of inspiratory muscle strength.