American journal of respiratory and critical care medicine
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Am. J. Respir. Crit. Care Med. · Jun 1995
Randomized Controlled Trial Comparative Study Clinical TrialRandomized, prospective trial of noninvasive positive pressure ventilation in acute respiratory failure.
Recent studies suggest that noninvasive positive pressure ventilation (NPPV) administered by nasal or oronasal mask avoids the need for endotracheal intubation, rapidly improves vital signs, gas exchange, and sense of dyspnea, and may reduce mortality in selected patients with acute respiratory failure, but few controlled trials have been done. The present study used a randomized prospective design to evaluate the possible benefits of NPPV plus standard therapy versus standard therapy alone in patients with acute respiratory failure. Patients to receive NPPV were comfortably fitted with a standard nasal mask connected to a BiPAP ventilatory assist device (Respironics, Inc., Murrysville, PA) in the patient flow-triggered/time-triggered (S/T) mode, and standard therapy consisted of all other treatments deemed necessary by the primary physician, including endotracheal intubation. ⋯ Among chronic obstructive pulmonary disease (COPD) patients, the reduction was even more striking, with 8 of 12 (67%) control patients requiring intubation compared with 1 of 11 (9%) NPPV patients (p < 0.05). Heart and respiratory rates were significantly lower in the NPPV group than in control patients within 1 h, and PaO2 was significantly improved in the NPPV group for the first 6 h. Dyspnea scores and maximal inspiratory pressures were better in the NPPV than in control patients at 6 h, and nurses and therapists spent similar amounts of time at the bedside for both groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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Am. J. Respir. Crit. Care Med. · Jun 1995
Effects of positive end-expiratory pressure on regional distribution of tidal volume and recruitment in adult respiratory distress syndrome.
The distribution of tidal volume (VT) and recruitment was investigated by chest computed tomography (CT) in eight sedated-paralyzed patients with the adult respiratory distress syndrome (ARDS). A CT section was obtained in the supine position at 0, 5, 10, 15, and 20 cm H2O positive end-expiratory pressure (PEEP) and at the corresponding inspiratory plateau pressure (21 +/- 1.8, 26 +/- 1.4, 31 +/- 1.8, 38 +/- 2.1, and 46 +/- 3.2 cm H2O [mean +/- SE]), keeping VT constant. ⋯ The following variables were computed at each lung level: (1) distribution of CT section tidal volume (VTct), i.e., the fraction of VT that inflates a given lung level; (2) the plateau-induced and PEEP-induced recruitment, i.e., the amount of lung tissue previously collapsed that inflates at plateau pressure and at PEEP, respectively; (3) the reopening-collapsing tissue, i.e., the amount of lung tissue that regains inflation at plateau pressure and collapses at PEEP. With increasing PEEP from 0 to 20 cm H2O, the VTct distribution decreased significantly (p < 0.01) in the upper levels, did not change in the middle levels, and increased significantly (p < 0.01) in the lower levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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Am. J. Respir. Crit. Care Med. · Jun 1995
Comparative StudyEffects of smoking and smoking cessation on longitudinal decline in pulmonary function.
Effects of cigarette smoking and smoking cessation on rate of FEV1 decline over 6 yr were examined in 4,451 Japanese-American men from the Honolulu Heart Program who were 45 to 68 yr of age at baseline (1965-1968). Within-person regression was used to calculate annual change in FEV1. Rates of FEV1 decline varied strongly with smoking status and increased significantly with age. ⋯ Among 216 men with impaired pulmonary function, those who quit smoking had significantly slower rates of FEV1 decline than did those who continued smoking. Potential reasons for quitting included respiratory conditions and stroke. These results extend previous reports of accelerated rates of FEV1 decline in the persons who continue to smoke, and they indicate that smoking cessation leads to less steep rates of decline in pulmonary function over a short period of time in middle-aged men, as well as in men with established pulmonary impairment.