The American review of respiratory disease
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Am. Rev. Respir. Dis. · Jul 1982
Randomized Controlled Trial Clinical TrialEffect of chest physiotherapy on the removal of mucus in patients with cystic fibrosis.
We studied the effectiveness of some of the components of a physiotherapy regimen on the removal of mucus from the lungs of 6 subjects with cystic fibrosis. On 5 randomized study days, after inhalation of a 99mTc-human serum albumin aerosol to label primarily the large airways, the removal of lung radioactivity was measured during 40 min of (a) spontaneous cough while at rest (control), (b) postural drainage, (c) postural drainage plus mechanical percussion, (d) combined maneuvers (postural drainage, deep breathing with vibrations, and percussion) administered by a physiotherapist, (e) directed vigorous cough. Measurements continued for an additional 2 h of quiet rest. ⋯ We conclude that in cystic fibrosis, vigorous, regimented cough sessions may be as effective as therapist-administered physiotherapy in removing pulmonary secretions. Postural drainage, although better than the control maneuver, was not as effective as cough and was not enhanced by mechanical percussion. Frequent, vigorous self-directed cough sessions are potentially as useful as more complex measures for effective bronchial toilet.
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Am. Rev. Respir. Dis. · Jul 1982
The oxygen cost of breathing in patients with cardiorespiratory disease.
We measured the oxygen cost of breathing (VO2resp) in 13 patients with cardiorespiratory disease requiring artificial ventilation as the difference between the oxygen consumption during spontaneous respiration (VO2tot) and that during artificial ventilation (VO2nonresp). Average VO2tot was 312 +/- 90 ml/min (mean +/- 1 SD), whereas VO2nonresp was 246 +/- 38 ml/min (p less than 0.01). Average VO2resp was 75 +/- 82 ml/min (range, 8 to 286), representing 24% of VO2tot or 8.7 +/- 8.9 ml O2/L ventilation. ⋯ The VO2resp had an exponential relationship with FEV1 (r = 0.97) in 6 patients who had had prior spirometry. Because minute ventilation was normal in our patients (8.8 +/- 2.2 L/min), the elevated VO2resp represented an increase in the work of breathing as well as a decrease in the efficiency of the respiratory muscles. These results suggest that, where O2 transport is compromised, artificial ventilation may release substantial quantities of oxygen for use by other body systems.
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Am. Rev. Respir. Dis. · Jul 1982
Case ReportsOccult positive end-expiratory pressure in mechanically ventilated patients with airflow obstruction: the auto-PEEP effect.
Alveolar pressure can remain positive throughout the ventilatory cycle of mechanically-ventilated patients with airflow obstruction, even when positive end-expiratory pressure (PEEP) is not applied intentionally. The increase of intrathoracic pressure associated with this "auto-PEEP" phenomenon can severely depress cardiac output as well as elevate the end-expiratory pulmonary artery wedge pressure. ⋯ Failure to recognize the hemodynamic consequences of auto-PEEP may lead to inappropriate fluid restriction or unnecessary vasopressor therapy. Although not apparent during normal ventilator operation, the auto-PEEP effect can be detected and quantified by a simple bedside maneuver: expiratory port occlusion at the end of the set exhalation period.
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Am. Rev. Respir. Dis. · Jul 1982
A simple procedure for the isolation of pulmonary parenchyma free of major blood vessels and airways for biochemical studies.
A new method of preparation of lung parenchyma free from small and medium sized airways and blood vessels is described. The lung is frozen in the inflated state and cut into thin slices to facilitate visualization and separation of large blood vessels and airways. ⋯ The fall-through portion consists almost entirely of alveoli. Amino acid analysis of elastin separated from the sieved fragments is similar to lung parenchymal elastin isolated and dissected from fresh lung tissue.