clinicaltrials.gov Identifier: NCT01822795.

We have recently observed obstructive apneas during nasal intermittent positive-pressure ventilation (nIPPV) and suggested that they were due to hypocapnia-induced glottic closure. To confirm this hypothesis, we studied seven healthy subjects and submitted them to nIPPV while their glottis was continuously monitored through a fiber-optic bronchoscope. During wakefulness, we measured breath by breath the widest inspiratory angle formed by the vocal cords at the anterior commissure along with several other indexes. Mechanical ventilation was progressively increased up to 30 l/min. In the absence of diaphragmatic activity, increases in delivered minute ventilation resulted in progressive narrowing of the vocal cords, with an increase in inspiratory resistance and a progressive reduction in the percentage of the delivered tidal volume effectively reaching the lungs. Adding CO2 to the inspired gas led to partial widening of the glottis in two of three subjects. Moreover, activation of the diaphragmatic muscle was always associated with a significant inspiratory abduction of the vocal cords. Sporadically, complete adduction of the vocal cords was directly responsible for obstructive laryngeal apneas and cyclic changes in the glottic aperture resulted in waxing and waning of tidal volume. We conclude that in awake humans passive ventilation with nIPPV results in vocal cord adduction that depends partly on hypocapnia, but our results suggest that other factors may also influence glottic width.

Background: Owing to its low incidence, the management of Mycobacterium xenopi pulmonary infections is not clearly defined. A multicentre retrospective study was performed to describe the features of the disease and to evaluate its prognosis. Methods: All patients with M xenopi satisfying the 1997 ATS/IDSA criteria from 13 hospitals in north-east France (1983France ( -2003 were included in the study. Clinical, radiological and bacteriological characteristics and data on the management and outcome were collected. Results: 136 patients were included in the analysis, only 12 of whom presented with no co-morbidity. Three types of the disease were identified: (1) a classical cavitary form in patients with pre-existing pulmonary disease (n = 39, 31%); (2) a solitary nodular form in immunocompetent patients (n = 41, 33%) and (3) an acute infiltrate form in immunosuppressed patients (n = 45, 36%). 56 patients did not receive any treatment; the other 80 patients received first-line treatment containing rifamycin (87.5%), ethambutol (75%), isoniazid (66.2%), clarithromycin (30%) or fluoroquinolones (21%). After a follow-up of 36 months, 80 patients (69.1%) had died; the median survival was 16 months (range 10-22). Two independent prognostic factors were found: the acute infiltrate form was associated with a bad prognosis (hazard ratio 2.6, p = 0.001) and rifamycin-containing regimens provided protection (hazard ratio 0.325, p = 0.006). Clarithromycin-containing regimens did not improve the prognosis. Conclusions: In contrast to recent guidelines, this study showed three different types of the disease (cavitary, nodular or diffuse infiltrate forms) with a different prognosis. In order to improve survival, all patients with M xenopi infection should be treated with a rifamycincontaining regimen. The usefulness of clarithromycin remains to be evaluated.Mycobacterium xenopi is a non-tuberculous mycobacterium responsible for lung disease, 1 especially in north-east France, south-east UK and in Ontario, Canada. 2 3 According to the recent ATS/ IDSA statement, its usual feature is an apical cavitary process in patients with obstructive pulmonary disease. 4 However, other features have been described. 5 M xenopi infections are difficult to treat and there is no standard treatment. 2 3 5 Rifampin, ethambutol and sometimes isoniazid or fluoroquinolones are usually recommended in combination with clarithromycin. 4 Two randomised clinical trials have been conducted by Jenkins et al. 6 7 In the first study, 42 patients were treated with rifampin and ethambutol with or without isoniazid, without any difference in the clinical response. 6 The overall mortality rate at 5 years was 69%. In the second study, Jenkins et al compared clarithromycin with a ciprofloxacin-containing regimen in 371 patients infected with non-tuberculous mycobacteria and found no difference in the 34 patients infected with M xenopi. 7 As M xenopi infection could present with different clinical and radiological patterns depending on the patient's immuno...

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