Respiratory muscle endurance training in chronic obstructive pulmonary disease: impact on exercise capacity, dyspnea, and quality of life.

Inspiratory muscle training may have beneficial effects in certain patients with chronic obstructive pulmonary disease (COPD). Because of the lack of a home training device, normocapnic hyperpnea has rarely been used as a training mode for patients with COPD, and is generally considered unsuitable to large-scale application. To study the effects of hyperpnea training, we randomized 30 patients with COPD and ventilatory limitation to respiratory muscle training (RMT; n = 15) with a new portable device or to breathing exercises with an incentive spirometer (controls; n = 15). Both groups trained twice daily for 15 min for 5 d per week for 8 wk. Training-induced changes were significantly greater in the RMT than in the control group for the following variables: respiratory muscle endurance measured through sustained ventilation (+825 +/- 170 s [mean +/- SEM] versus -27 +/- 61 s, p < 0.001), inspiratory muscle endurance measured through incremental inspiratory threshold loading (+58 +/- 10 g versus +21.7 +/- 9.5 g, p = 0.016), maximal expiratory pressure (+20 +/- 7 cm H(2)O versus -6 +/- 6 cm H(2)O, p = 0.009), 6-min walking distance (+58 +/- 11 m versus +11 +/- 11 m, p = 0.002), V O(2peak) (+2.5 +/- 0.6 ml/kg/min versus -0.3 +/- 0.9 ml/kg/min, p = 0.015), and the SF-12 physical component score (+9.9 +/- 2.7 versus +1.8 +/- 2.4, p = 0.03). Changes in dyspnea, maximal inspiratory pressure, treadmill endurance, and the SF-12 mental component score did not differ significantly between the RMT and control groups. In conclusion, home-based respiratory muscle endurance training with the new device used in this study is feasible and has beneficial effects in subjects with COPD and ventilatory limitation.

Nd-YAG laser ignition of silicone endobronchial stents.

STUDY OBJECTIVES: To test the incendiary characteristics of various silicone endobronchial stents under the impact of the Nd-YAG laser. DESIGN: In vitro study in the laser laboratory of a university-affiliated city hospital. SETTING: The experiments were performed in a reaction chamber under controlled oxygen concentrations. The radiolucent and radiopaque Dumon silicone stent (Novatech; Aubagne, France) and the tracheal part of the Dynamic stent (Ruesch AG; Kernen, Germany) were tested. The Dumon stents were either clean, covered with a thin layer of blood, or mounted on fresh pig tracheal wall. The laser was aimed on them perpendicularly from distances of 1.0 cm and 0.5 cm. INTERVENTIONS: Minimal oxygen concentration to allow ignition and impact time for power outputs (POs) between 10 W and 80 W were determined. MEASUREMENTS AND RESULTS: The lowest oxygen concentration that allowed ignition of some stents was 40%. The clean radiolucent stent could not be ignited with up to 100% ambient oxygen concentration. Radiopacity, presence of blood, tracheal wall, and metal, as well as higher PO and shorter distance of the laser probe decreased impact time to ignition. The radiopaque blood-covered stent was most easily ignited. For this stent, at a PO of 40 W, impact time to ignition was 1.5 +/- 0.2 s, and at 30 W was 2.6 +/- 0.3 s. CONCLUSIONS: At ambient oxygen concentrations > or = 40%, silicone stents can catch fire. Depending on the condition of the stent, the distance of the laser probe, and PO, ignition can occur after short impact times. To prevent stent ignition, oxygen concentration should be kept < 40%. When unusual circumstances require working with higher oxygen concentrations, pulse duration needs to be limited or stent removal might be considered before firing the laser.

Eosinophilic pneumonia and respiratory failure associated with venlafaxine treatment.

Drugs are well known causes of eosinophilic lung disease. In many patients, symptoms increase slowly, pulmonary infiltrates and eosinophilia progress over weeks, and resolve upon withdrawal of the offending agent. Rarely, the disease presents like acute eosinophilic pneumonia with acute onset of symptoms and rapidly progressing infiltrates which may be associated with respiratory failure. This report describe a case of venlafaxine-induced acute eosinophilic pneumonia causing respiratory insufficiency that rapidly resolved upon institution of corticosteroid treatment. This 5-hydroxytryptamine and noradrenaline reuptake inhibitor was previously not known to cause lung or peripheral blood eosinophilia. Considering the increasing use of this class of medication physicians have to be aware of this life-threatening and fully reversible complication.

Decompensated cor pulmonaleas the first manifestation of adult-onset myopathy.

A 46-year-old white female was admitted for decompensated cor pulmonale (CP). It had not interfered with her daily activities and she had not experienced shortness of breath, fatigue or muscle weakness prior to the onset of right heart failure. A thorough investigation revealed severe generalized muscle weakness with restrictive chest bellows disease and secondary CP (mean pressure in the pulmonary artery 60 mm Hg). After having refused respiratory support the patient died a few days after admission. The muscle biopsy was consistent with adult-onset acid-maltase deficiency. This is a rare case of metabolic myopathy presenting as decompensated CP without previous symptoms of muscle weakness. This condition can easily be treated with nocturnal ventilatory support, improving the quality and length of life.

Effect of high-frequency oral airway and chest wall oscillation and conventional chest physical therapy on expectoration in patients with stable cystic fibrosis.

STUDY OBJECTIVE: To compare the effect of high-frequency oral airway oscillation, high-frequency chest wall oscillation, and conventional chest physical therapy (CPT) on weight of expectorated sputum, pulmonary function, and oxygen saturation in outpatients with stable cystic fibrosis (CF). DESIGN: Prospective randomized trial. SETTING: Pediatric pulmonary division of a tertiary care center. PATIENTS: Fourteen outpatients with stable CF recruited from the CF center. INTERVENTIONS: Two modes of oral airway oscillation (1: frequency 8 Hz; inspiratory to expiratory [I:E] ratio 9:1; 2: frequency 14 Hz; I:E ratio 8:1), two modes of chest wall oscillation (1: frequency 3 Hz; I:E ratio 4:1; 2: frequency 16 Hz; I:E ratio 1:1, alternating with frequency 1.5 Hz, I:E ratio 6:1), and CPT (clapping, vibration, postural drainage, and encouraged coughing) were applied during the first 20 min of 4 consecutive hours. MEASUREMENTS AND RESULTS: Sputum was collected on an hourly basis for a total of 6 consecutive hours. During the first and the last hour, patients collected sputum without having any treatment and underwent pulmonary function tests (PFTs). Oxygen saturation was measured at 30-min intervals during hours 1 to 6. For the first 20 min of the second to the fifth hour, patients received one of the treatments. To assess the effect of the intervention, the weight of expectorated sputum during hours 2 to 6 was averaged and expressed as percentage of the weight expectorated during the first hour (baseline). For the five treatment modalities, mean sputum dry and wet weights ranged between 122% and 185% of baseline. There was no statistically significant difference among the treatment modalities. As measured by sputum wet weight, all oscillatory devices tended to be less effective than CPT (p=0.15). As measured by dry weight, oral airway oscillation at 8 Hz with an I:E ratio of 9:1 and CPT tended to be more effective than the other treatment modalities (p=0.57). None of the treatment modalities had an effect on PFTs and oxygen saturation and all were well tolerated. CONCLUSION: In outpatients with stable CF, high-frequency oscillation applied via the airway opening or via the chest wall and CPT have comparable augmenting effects on expectorated sputum weight without changing PFTs or oxygen saturation. In contrast to CPT, high-frequency oral airway and chest wall oscillations are self-administered, thereby containing health-care expenses.

Scavenging of reactive oxygen species by a glycolipid fraction of Mycobacterium avium serovar 2.

Previous experiments indicated that MIF-A3, a peptidoglycolipid extracted from Mycobacterium avium serovar 2 (Mycobacterium paratuberculosis 18), inhibits the killing of Candida albicans by activated bovine peripheral blood-derived macrophages and murine thioglycollate-elicited peritoneal macrophages in vitro. Subsequent in vitro data from our laboratory indicated that this reduction in killing may be related to the ability of MIF-A3 to scavenge reactive oxygen species (ROS). In this study we examined this hypothesis directly by determining if MIF-A3 reduced exogenous H2O2-induced candidacidal activity. When Candida albicans was incubated with H2O2 (4 mM) alone, colony-forming units/ml x 10(4) (CFU/ml) were 0.4 +/- 0.1 (mean +/- SE, n = 4) as compared to 11.3 +/- 2.0 CFU/ml in control (untreated) cultures (p < .05). The addition of catalase at concentrations > or = 6.8 U/ml, completely blocked the fungicidal effect of H2O2. However, reducing the amount of catalase from 6.8 U/ml to 3.4 U/ml resulted in a loss of scavenging activity, which was associated with a 50% increase in H2O2-mediated killing. Substituting MIF-A3 (400 micrograms/ml) for catalase, also reduced H2O2-induced fungicidal activity. In the absence of MIF-A3, H2O2 reduced Candida albicans to less than 10(3) CFU/ml. However, in the presence of MIF-A3 the CFU/ml of Candida albicans increased 7.5-fold. Based on concentration-response curves of H2O2 inhibition vs. increasing amounts of catalase we determined that the relative inhibitory capacity of the MIF-A3 (400 micrograms/ml) was approximately 1.0 U/ml "catalase equivalents." These findings provide direct evidence that MIF-A3 can scavenge H2O2, and reduce H2O2-induced killing of Candida albicans.