Sniff nasal inspiratory pressure (SNIP) measurement is a volitional noninvasive assessment of inspiratory muscle strength. A maximum of 10 sniffs is generally used. The purpose of the present study was to investigate whether the maximum SNIP improved after the tenth sniff.In total, 20 healthy volunteers and 305 patients with various neuromuscular and lung diseases were encouraged to perform 40 and 20 sniffs, respectively.The best SNIP among the first 10 sniffs was lower than the best SNIP among the next 10 sniffs in the healthy volunteers and patients. The SNIP improvement after the twentieth sniff was marginal.In conclusion, a learning effect persists after the tenth sniff. The current authors suggest using 10 additional sniffs when the best result of the first 10 sniffs is slightly below normal, or when sniff nasal inspiratory pressure is used to monitor a progressive decline in inspiratory muscle strength.

Nutritional status is both important and difficult to assess in patients with Duchenne muscular dystrophy (DMD), particularly in those requiring mechanical ventilation (MV). The current authors evaluated body composition (bio-impedancemetry), resting energy expenditure (REE; indirect calorimetry) and energy intake in 20 adult patients with DMD using home MV (nocturnal: n513; continuous: n57) and 12 age-matched healthy controls.The patients were smaller in height than the controls and had a lower body weight. Most of the reduction in body mass index was accounted for by a reduction in fat free mass (FFM). REE (kJ) was significantly reduced in the patients (4559¡853 kJ?24 h -1 versus 7407¡1312 kJ?24 h -1), but the difference disappeared after correction for FFM.REE and FFM were correlated in both the controls and patients, but less strongly in the latter, the lower strength of the association being due to the patients using continuous MV (REE and FFM uncorrelated). The food intake of the patients was 1.2¡0.4 greater than their REE.This study shows that patients with advanced forms of Duchenne muscular dystrophy have balanced energy intakes and resting energy expenditure.

The purpose of this study was to estimate the prevalence of malnutrition in outpatients on long-term oxygen therapy or home mechanical ventilation, to determine the relationships between malnutrition and impairment/disability and smoking and also to identify relevant tools for routine nutritional assessment.In 744 patients (M:F 1.68, aged 65¡15 yrs) with chronic obstructive pulmonary disease (COPD, 40%), restrictive disorders (27%), mixed respiratory failure (15%), neuromuscular diseases (13%) and bronchiectasis (5%), body mass index (BMI), fatfree mass (FFM), serum albumin, transthyretin, 6-min walking test, forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and blood gases were recorded.FFM was the most sensitive parameter for detecting malnutrition, being abnormal in 53.6% of patients, while BMI was v20 in 23.2%, serum albumin v35 g?L -1 in 20.7 %, and serum transthyretin v200 mg?L -1 in 20%. FFM depletion predominated in neuromuscular, bronchiectasis and restrictive disorders. BMI and FFM were correlated with FEV1, FVC and 6-min walking test. In multivariate analysis a BMIv20 was related to FEV1 and smoking habits, and a low FFM to smoking, FEV1 and female sex.Malnutrition is highly prevalent in home-assisted respiratory patients and is related to causal disease, forced expiratory volume in one second, smoking and disability. Fatfree mass appeared to be the most sensitive and relevant nutritional parameter according to impairment and disability.

Inspiratory muscle strength monitoring is crucial in patients with neuromuscular disorders. The sniff nasal inspiratory pressure (SNIP) and maximal inspiratory pressure (PI,max) are usually measured. The present study investigated whether the test yielding the best value at baseline continued to yield the best value during follow-up.The present study included 25 patients with Duchenne muscular dystrophy (DMD) and 61 with myotonic muscular dystrophy (MMD). SNIP and PI,max were measured at baseline and then annually.At baseline, SNIP was lower than PI,max in 20 (80%) DMD patients and 32 (52%) MMD patients. During follow-up in DMD patients, changes in the best method always occurred from SNIP to PI,max. In MMD patients, when SNIP was better than PI,max at baseline, SNIP was usually (88%) better during follow-up, whereas a better PI,max than SNIP at baseline was frequently (50%) followed by a shift to SNIP.Maximal inspiratory pressure may be sufficient for monitoring inspiratory muscle function in Duchenne muscular dystrophy adults. In myotonic muscular dystrophy, the marked variability in the test yielding the best value at baseline indicates a need for performance of both tests at baseline. However, when sniff nasal inspiratory pressure measurement yields the best value at baseline, using sniff nasal inspiratory pressure alone during follow-up may be appropriate.

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