Articles: respiratory-distress-syndrome.
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Randomized Controlled Trial Comparative Study Clinical Trial
Dose-response curves of inhaled nitric oxide with and without intravenous almitrine in nitric oxide-responding patients with acute respiratory distress syndrome.
Inhaled nitric oxide, a selective pulmonary vasodilator, in combination with intravenous almitrine, a selective pulmonary vasoconstrictor, markedly improves arterial oxygenation in 50-60% of patients with acute lung injury. The goal of this study was to assess dose response of inhaled nitric oxide with and without almitrine in patients with acute respiratory distress syndrome responding to nitric oxide. ⋯ In 6 patients with early acute respiratory distress syndrome and highly responsive to inhaled nitrix oxide, the administration of intravenous almitrine at a concentration of 16 micrograms.kg-1.min-1 induced an additional increase in Pao2. Dose response of nitric oxide was not changed by the administration of almitrine and a plateau effect was observed at inspiratory nitric oxide concentrations of 1.5 ppm.
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Am. J. Respir. Crit. Care Med. · Nov 1995
Comparative StudyProspective validation of an acute respiratory distress syndrome predictive score.
We derived an Acute Respiratory Distress Syndrome Score (ARDS Score) from previously described training set data. To validate its diagnostic accuracy for identifying a complicated course (early death or prolonged intubation) in acute lung injury, 50 patients were prospectively scored using an ARDS Score decision threshold of > or = 2.5 to discriminate between an uncomplicated (successful extubation after < or = 14 d) and complicated course. Predictor factors incorporated in the ARDS Score were collected on Day 4 and Day 7 of ARDS and included PaO2/PAO2 ratio, required positive end-expiratory pressure (PEEP), and chest radiograph progression. ⋯ The LIS components of static respiratory system compliance (Crs) and chest radiograph description did not differ between patient groups. The interobserver concordance of the dynamic chest radiograph interpretation included in the ARDS Score was significant (p < 0.05). We conclude that the previously derived ARDS Score has valid diagnostic accuracy for identifying patients with ARDS who will follow a complicated course.
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Clinical Trial Controlled Clinical Trial
Permissive hypercapnia in trauma patients.
The use of a normal tidal volume in patients with progressive loss of alveolar airspace may increase inspiratory pressure and overdistend remaining functional alveoli. Permissive hypercapnia (PH) is a ventilator management technique that emphasizes control of alveolar pressure, rather than PCO2. The purpose of this study was to determine if the use of PH is associated with an improved outcome from adult respiratory distress syndrome (ARDS). ⋯ The duration of mechanical ventilation was greater in PH patients [49.2 +/- 15.2 vs. 20.8 +/- 10 days (p < 0.01)]. Survival was also greater in the PH group [91% vs. 48% (p < 0.01)]. A reduction in intensity of mechanical ventilation is associated with a prolongation of ventilatory support and an improved outcome from ARDS.
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Randomized Controlled Trial Clinical Trial
Gas exchange indices--how valid are they?
This study examined the arterial-alveolar oxygen tension difference (AaDO2), arterial oxygen tension to inspired oxygen fraction ratio (PaO2/FiO2) and alveolar to arterial oxygen tension ratio (PAO2/PaO2) with regard to: (i) their correlation with the calculated pulmonary shunt in critically ill patients; and (ii) the influence of the inspired oxygen fraction on these indices before, during and after general anaesthesia. ⋯ The so-called non-invasive indices of pulmonary gas exchange do not correlate well with the calculated pulmonary shunt, which is regarded as the gold standard that reflects the various components of gas exchange. We speculate that the poor performance of these indices can be explained by the fact that they do not take into account the mixed venous saturation and, except for the alveolar to arterial oxygen tension ratio, ignore the effects of alveolar ventilation. The effect of the inspired oxygen fraction on these ratios makes them difficult to interpret if similar inspired oxygen fractions are not used. The effect of the FiO2 on these indices could possibly be explained by the denitrogenation and collapse of alveoli with low ventilation perfusion ratios. The change in the slope of the FiO2 and the indices that was demonstrated during anaesthesia could possibly be explained by the expected change in the mixed venous saturation that occurs during anaesthesia.
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Inflammatory cytokines (ICs) are important modulators of injury and repair. ICs have been found to be elevated in the BAL of patients with both early and late ARDS. We tested the hypothesis that recurrent injury to the alveolocapillary barrier and amplification of intra-alveolar fibroproliferation observed in nonresolving ARDS is related to a persistent inflammatory response. For this purpose, we obtained serial measurements of BAL IC and correlated these levels with lung injury score (LIS), BAL indexes of endothelial permeability (albumin, total protein [TP]), and outcome. ⋯ Our findings indicate that an unfavorable outcome in ARDS is associated with an initial, exaggerated, pulmonary inflammatory response that persists unabated over time. Plasma IC levels parallel changes in BAL IC levels. The BAL:plasma ratio results suggest, but do not prove, a pulmonary origin for IC production. BAL TNF-alpha, IL-1 beta, and IL-8 levels correlated with BAL indices of endothelial permeability. In survivors, reduction in BAL IC levels over time was associated with a decline in BAL albumin and TP levels, suggesting effective repair of the endothelial surface. These findings support a causal relationship between degree and duration of lung inflammation and progression of fibroproliferation in ARDS.