Tracheobronchopathia osteochondroplastica. An underrecognized entity?

Tracheobronchopathia osteochondroplastica (TPO) is an idiopathic disease of the trachea and major bronchi characterized by multiple submucosal osteocartilaginous nodules. The nodules may be either focal or diffuse, and typically spare the membranous wall of the airways. Symptoms are non-specific, and include dry cough, dyspnea, recurrent respiratory infections and occasionally hemoptysis. TPO is rarely considered as a diagnosis in part due to lack of awareness among clinicians. The diagnosis can be based on a typical bronchoscopic appearance and generally does not require biopsy of the lesions. When available, histology reveals bone formation within the submucosa with normal overlying respiratory epithelium. TPO is a benign disorder, marked by a generally favorable clinical evolution. There is currently no established treatment for the removal of airway nodules, or the prevention of further tissue growths. Interventional bronchoscopy techniques have a role in the relief of symptomatic airway obstruction, when indicated.

Non-invasive measurement of the mean alveolar O(2) tension from the oxygen uptake versus tidal volume curve.

AIMS: The classical equations for measuring the mean and the ideal alveolar O(2) tension are based on assumptions, which are shown to be invalid. So we thought to develop a new, non-invasive method for measuring the mean alveolar P,O(2) within the volume domain (PA,O(2(Bohr))). This method is based on the oxygen uptake vs. tidal volume curve (VO(2) vs. VT) obtained during tidal breathing of room air and/or air enriched with oxygen. METHODS: PA,O(2(Bohr)) and the ideal alveolar PO(2) (PA,O(2(ideal))) were simultaneously measured in 10 healthy subjects and 34 patients suffering from chronic obstructive pulmonary disease (COPD) breathing tidally room air at rest. Additionally, 10 subjects (three healthy subjects and seven COPD patients) were studied while breathing initially room air and subsequently air enriched with oxygen. RESULTS: According to the results, PA,O(2(Bohr)) considerably differed from PA,O(2(ideal)) (P = 0.004). The cause of the difference, at the individual's R, is: (1) the difference between the arterial and Bohr's alveolar CO(2) tension, mainly in COPD patients, and (2) the inequality between Bohr's alveolar part of the tidal volume for CO(2) and O(2). Furthermore, end-tidal gas tension (PET,CO(2) and PET,O(2)) differed from Pa,CO(2) and PA,O(2(Bohr)) respectively. CONCLUSION: The deviation of PA,O(2(Bohr)) from PA,O(2(ideal)) has a definite impact on Bohr's dead space ratio for O(2) and CO(2), and on the alveolar-arterial O(2) difference. The difference (PA,O(2(Bohr)) - PA,O(2(ideal))) is not related to the pathology of the disease. So, gas exchange within the lungs should be assessed at the subject's R from PA,O(2(Bohr)) and PA,CO(2(Bohr)) but not from PA,O(2(ideal)) nor Pa,CO(2).

A case of uncomplicated pulmonary alveolar proteinosis evolving to pulmonary fibrosis.

Pulmonary alveolar proteinosis (PAP) is a rare syndrome characterised by intra-alveolar accumulation of surfactant components and cellular debris, with minimal interstitial inflammation or fibrosis. Since surfactant accumulates abnormally, a disturbance in the normal pathway of surfactant production, metabolism, recycling or degradation has been postulated. This disease has a variable clinical course: from spontaneous resolution to respiratory failure and death due to disease progression or superimposed infections. PAP leading to pulmonary fibrosis is rarely seen, and few case reports describe this association. Here, we describe the case of a patient with a diagnosis of PAP confirmed by open lung biopsy, who developed interstitial pulmonary fibrosis years after disease onset.

Unevenness of ventilation assessed by the expired CO(2) gas volume versus V(T) curve in asthmatic patients.

Recently, we have shown that the expired CO2 gas volume versus tidal volume (VCO2-VT) curve is a useful tool for assessing unevenness of ventilation because it allows the separation of tidal volume into three functional compartments: (a) the CO2-free expired air (V0), (b) the transitional volume (Vtr), (c) the alveolar volume (VA) and the measurement of alveolar FCO2 during resting breathing in normal subjects and patients with COPD. In this paper, we have investigated whether changes pertaining to unevenness of ventilation taking place immediately after the administration of methacholine can be assessed using the VCO2-VT curve in asthmatic patients. The VCO2-VT curve was obtained during tidal breathing from 16 stable asthmatic patients who underwent a methacholine challenge test. It has been found that the Vtr, and hence Bohr's dead space (VD,Bohr = V0 + Vtr), over tidal volume ratios were significantly increased immediately after the methacholine administration, whilst the V0 over tidal volume ratio was not affected. The change of the above ratios was not related to the percentage decrease of FEV1.0 following methacholine administration.