The American review of respiratory disease
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Am. Rev. Respir. Dis. · Jan 1990
Oxygen radical production by alveolar inflammatory cells in idiopathic pulmonary fibrosis.
Idiopathic pulmonary fibrosis (IPF) is a chronic inflammatory interstitial lung disease characterized by the accumulation of alveolar macrophages (AMs) and neutrophils in the lower respiratory tract, parenchymal cell injury, and fibrosis of the alveolar structure. Reactive oxygen intermediates (ROI) are claimed to be a major cause of tissue damage in IPF; however, the source of ROI has not been unequivocally identified. AMs, as well as neutrophils, are capable of releasing these agents. ⋯ In comparison with the controls, the spontaneous as well as the stimulated ROI release of total BAL cells in IPF are markedly increased (20,763.9 +/- 5,079.3 versus 2,509.5 +/- 300.6 counts/10 s/2.10(5) cells, spontaneously, IPF versus control; 106,819.3 +/- 33,802.8 versus 8,919 +/- 1,357.9 PMA induced; 41,597.1 +/- 8,442.6 versus 6,223.8 +/- 1,025.1 zymosan induced, p less than 0.001). Measurement of the ROI release of purified AMs revealed that these cells produce the bulk part of ROI released by BAL cells (84%). In spite of the fact that, on a per cell basis, the ROI release of neutrophils is 1.7-fold of that of AMs, there is no correlation between the ROI production of total BAL cells and the percentage of neutrophils in BAL, demonstrating a minor role of these cells in the generation of the total ROI burden in IPF.(ABSTRACT TRUNCATED AT 250 WORDS)
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Am. Rev. Respir. Dis. · Nov 1989
End-tidal carbon dioxide in critically ill patients during changes in mechanical ventilation.
Values of end-tidal CO2 (PETCO2) approximate PaCO2 in spontaneous breathing normal subjects and in stable patients receiving mechanical ventilatory support (MVS). Because marked inequality of ventilation/perfusion ratios in critically ill patients might affect this correlation, we assessed changes of PETCO2 in predicting changes in PaCO2 (delta PaCO2) and changes in minute ventilation (delta Ve) in this patient population. Twenty consecutive intubated patients 38 to 89 yr of age (mean, 70 yr) with respiratory failure while receiving MVS with indwelling arterial lines were studied. ⋯ In four patients, the trend in their PETCO2 during changes in mechanical ventilation were in the opposite direction from the trend in their PaCO2. Thus, many critically ill patients, who cannto be preidentified, have an inconstant PaCO2-PETCO2 gradient with changes of ventilation. Utilization of PETCO2 as a noninvasive monitoring substitute for trends in PaCO2 in critically ill patients may be misleading despite establishing an initial PaCO2-PETCO2 relationship.
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Am. Rev. Respir. Dis. · Nov 1989
Comparative StudyObstructive sleep apnea with severe chronic airflow limitation. Comparison of hypercapnic and eucapnic patients.
The mechanism of sustained awake hypercapnia in the obstructive sleep apnea syndrome (OSA) is unknown. Recent work has implicated coexisting chronic airflow limitation (CAL) as an important contributing factor. We approached this question by studying consecutive patients with both OSA syndrome and severe CAL in detail and comparing those with and without retention of CO2 while awake. ⋯ The mean values for FEV1, VC, lung volumes, and diffusing capacity for CO measured while awake did not differ. The hypercapnic group had lower awake PaO2 levels (p less than 0.001), were heavier (p less than 0.05), had narrower upper airway size on CT scan measurements (p less than 0.01), and gave a history of much heavier alcohol intake (p less than 0.05). Our results demonstrate that some patients with severe OSA and severe CAL can maintain normal awake arterial CO2 levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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Am. Rev. Respir. Dis. · Oct 1989
Randomized Controlled Trial Comparative Study Clinical TrialUse and misuse of metered-dose inhalers by patients with chronic lung disease. A controlled, randomized trial of two instruction methods.
Metered-dose inhalers are often used incorrectly by patients with chronic airflow obstruction, and there is a lack of controlled studies designed to evaluate methods to teach the correct use of these devices. Therefore, we screened 100 consecutive stable outpatients for correct or incorrect inhaler use and then conducted a randomized trial of two methods to teach correct use. Patients were classified as correct or incorrect users with a modified metered-dose inhaler containing a thermistor that detected inspiration, inhaler activation, and the duration of breath-holding. ⋯ For all subjects, the proportion using correct technique declined over time, particularly for incorrect users. We also examined a series of patient characteristics, obtained by questionnaire and spirometry, to determine whether they could be used in the clinical setting to identify incorrect users. By discriminant analysis, a group of four variables predicted correct metered-dose inhaler use: bronchodilator responsiveness, a history of additional about proper technique, verbal knowledge of the correct inhaler maneuvers, and the patient's perception of whether it is important to use an inhaler.(ABSTRACT TRUNCATED AT 250 WORDS)