Chest
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To examine the relationship of expired capnograms and respiratory system resistance (Rrs) in intubated critically ill patients, we consecutively studied 41 mechanically ventilated patients to (1) analyze the association between expired CO2 slope and auto-positive end-expiratory pressure (auto-PEEP), between Rrs and auto-PEEP, between Rrs and expired CO2 slope, and between Rrs and arterial minus end-tidal PCO2 gradient (PaCO2-PETCO2 gradient) and (2) to investigate the capacity of the expired CO2 slope and PaCO2-PETCO2 gradient to predict Rrs during mechanical ventilation. Regression analysis found a close correlation between Rrs and expired CO2 slope (r = 0.86; p < 0.001), between Rrs and auto-PEEP (r = 0.75; p < 0.001), and between auto-PEEP and expired CO2 slope (r = 0.74; p < 0.001). ⋯ These observations suggest that CO2 elimination in critically ill patients is strongly modulated by lung, airway, endotracheal tube, and ventilator equipment resistances. Although continuous capnogram waveform monitoring at the bedside might be useful to assess Rrs, very accurate predictions could be done only in determinate patients.
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Current treatment strategies for asthma and chronic obstructive pulmonary disease (COPD) emphasize the inhalation route, yet patients often misuse metered-dose inhalers (MDI). To address this problem, patient education by medical personnel has been recommended and a variety of alternate inhaler devices have been developed. ⋯ We conclude that (1) many medical personnel responsible for monitoring and instructing patients in optimal inhaler use lack rudimentary skills with these devices, (2) nurses and physicians seldom receive formal training in the use of inhaling devices, and (3) newer inhaling devices designed to obviate problems of technique are at present less likely to be used well by medical personnel soon after their introduction.
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The purpose of this study was to determine the correlation between different intervals in the 12-min walk test, to determine which of the intervals best correlated with maximal oxygen intake (VO2max) and maximal CO2 expelled (VCO2max) and to determine the degree of correlation between changes in the VO2max and changes in the walk test and spirometry. Nine elderly (age, 67 +/- 4 years) patients with moderate COPD (FEV1, 1.32 +/- 0.28 L) who were ventilatory limited were seen 6 times over a 14-week period. At each visit they performed spirometry, a 12-min walk, and a symptom-limited maximal exercise test. ⋯ The correlation coefficients between the distance walked at various intervals and the oxygen consumption (VO2)/kg (approximately 0.65) and the VCO2/kg (approximately 0.52) were very similar. However, changes in the VO2/kg were more closely correlated with changes in the 12-min walk (r = 0.72), than with changes in the 6-min walk (r = 0.64), the 4-min walk (r = 0.59), or the 2-min walk (r = 0.53). This latter observation suggests that the 12-min walk may be preferable to tests in which the patient walks 4 or 6 min for documenting changes in the exercise capabilities.
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An autopsy was performed on a patient who had chronic hypersensitivity pneumonitis that was observed for 9 years. The patient was a farmer who developed symptoms every March through July during the use of moist hay that was infected heavily with Candida. Precipitins and an inhalation challenge test to C albicans were positive. We interpret the role of C albicans in this case.
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Prior studies have shown that nasal intermittent positive pressure ventilation (NIPPV) can improve arterial blood gas values, prevent symptoms resulting from alveolar hypoventilation, and decrease hospitalization in patients with chronic respiratory failure. Most studies have involved small samples of patients followed up for a limited time. This study reviews our experience during 5 years use of NIPPV in 276 patients with kyphoscoliosis, posttuberculosis sequelae, Duchenne-type muscular dystrophy, COPD, and bronchiectasis followed up for > or = 3 years while receiving NIPPV. ⋯ Benefit was also more short term for patients with COPD and bronchiectasis. NIPPV can sustain improvement in gas exchange, while reducing hospitalization for substantial periods of time. NIPPV can be an attractive and effective alternative to other methods of assisted ventilation such as TIPPV.