American journal of respiratory and critical care medicine
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Am. J. Respir. Crit. Care Med. · May 1996
Comparative StudyLung mechanics and dyspnea after lung transplantation for chronic airflow obstruction.
Single lung transplantation (SLT) is widely used to treat chronic airflow obstruction (CAO). During exercise the native lung should increase end-expiratory lung volume (EELV) and result in a different respiratory sensation compared with double lung transplantation (DLT). Eight SLT recipients and 12 DLT recipients demonstrated a similar maximal work load and achieved VO2. ⋯ Tidal flow volume loop analysis demonstrated encroachment of the expiratory limb in four of seven SLT patients but in only one of 12 DLT recipients. A lesser peak breathlessness in DLT recipients approached statistical significance (p = 0.051), although the relation of respiratory sensation versus VE or VO2% predicted did not differ between the two groups. EELV increases in SLT recipients at peak exercise, although overall aerobic response is preserved and respiratory sensation is similar.
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Am. J. Respir. Crit. Care Med. · May 1996
Randomized Controlled Trial Comparative Study Clinical TrialHome versus intensive care pressure support devices. Experimental and clinical comparison.
A bench study using an artificial lung model and a clinical study in patients were performed to evaluate six commercially available home pressure support devices. Six devices were tested in the in vitro study, including five designed for home use and one designed for use in intensive care units. Minimal positive end-expiratory pressure (PEEP) varied across home devices, from 0.5 cm H2O to 4.3 cm H2O. ⋯ However, the esophageal pressure-time product was 30% higher with the home device (165 +/- 93 versus 119 +/- 80 cm H2O/min, p < 0.05). In conclusion, differences exist between devices in terms of occurrence of rebreathing, speed of attainment of stable pressure support level, and expiratory resistance. These differences characterizing the delivery of pressure support may have clinical impact on the inspiratory effort of patients.
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Am. J. Respir. Crit. Care Med. · May 1996
Relationship of isoniazid resistance to human immunodeficiency virus infection in patients with tuberculosis.
To investigate the relationship between isoniazid resistance and HIV infection in patients with tuberculosis, we evaluated data in the Los Angeles County tuberculosis registry on 1,506 patients for whom drug susceptibility results were available. Among 235 HIV-infected patients, isoniazid resistance was less common than in 1,271 patients who were HIV-seronegative or who had not been tested for HIV, with an unadjusted odds ratio of 0.3. After adjustment for other factors that affect drug resistance (ethnicity, country of birth, prior diagnosis of tuberculosis, and cavitation), the frequency if isoniazid resistance remained lower than that in patients without HIV infection, with an odds ratio of 0.4 (95% confidence interval, 0.2 to 0.8; p = 0.02). We conclude that in Los Angeles, a setting where there is no ongoing outbreak of drug-resistant tuberculosis, isoniazid-resistant tuberculosis is not more common in HIV-infected patients.
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Am. J. Respir. Crit. Care Med. · May 1996
Comparative StudyMuscle weakness in mechanically ventilated patients with severe asthma.
Patients who undergo mechanical ventilation for severe asthma are at risk of developing diffuse muscle weakness because of acute myopathy. The relative importance of corticosteroids and neuromuscular paralysis in causing the myopathy is controversial, and it is uncertain whether the chemical structure of the drug used to induce paralysis influences the risk of myopathy. Using a retrospective cohort study design, we evaluated 107 consecutive episodes of mechanical ventilation for severe asthma to assess (1) the incidence of clinically significant weakness in patients treated with corticosteroids alone versus corticosteroids with neuromuscular paralysis, (2) the influence of the duration of paralysis on the incidence of muscle weakness, and (3) the relative risk of weakness in patients paralyzed with the nonsteroidal drug atracurium versus an aminosteroid paralytic agent (pancuronium, vecuronium). ⋯ Eighteen of the 20 weak patients had been paralyzed for more than 24 h. The incidence of weakness was not reduced when paralysis was achieved with atracurium as opposed to an aminosteroid neuromuscular blocking agent. In conclusion, corticosteroid-treated patients with severe asthma who undergo prolonged neuromuscular paralysis are at significant risk for the development of muscle weakness, and the risk of weakness is not reduced by use of atracurium.
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Am. J. Respir. Crit. Care Med. · May 1996
Comparative StudyEffect of hypertonic saline, amiloride, and cough on mucociliary clearance in patients with cystic fibrosis.
In patients with cystic fibrosis (CF), dehydration of airway secretions leads to a decrease in mucociliary clearance (MCC). We examined the acute effect of MCC of a single administration by aerosolization of hypertonic saline (7%) (HS), amiloride (0.3% in 0.12% NaCl) (AML) and a combination of AML and HS (AML + HS) in 12 patients with CF using a radioaerosol technique. Isotonic saline [0.9%] (IS) was used as a control solution. ⋯ Comparison of the amount of radioaerosol cleared from the right lung was made at 60 min (%C60) and 90 min (%C90) using repeated measures ANOVA. The percent cleared at 60 and 90 min was significantly increased with HS (%C60 = 26.5%, %C90 = 29.4%) and the combination of AML + HS (%C60 = 23.1%, %C90 = 27.4%) compared with both IS (%C60 = 14.7%, %C90 = 17.5%) and COUGH (%C60 = 18.0%, %C90 = 19.5%), p < 0.01. Inhalation of hypertonic saline is a potentially useful treatment in patients with cystic fibrosis.