1.
Oxygen therapy at low flow causes oxidative stress in chronic obstructive pulmonary disease: Prevention by N-acetyl cysteine.
Foschino Barbaro, MP, Serviddio, G, Resta, O, Rollo, T, Tamborra, R, Elisiana Carpagnano, G, Vendemiale, G, Altomare, E
Free radical research. 2005;(10):1111-8
Abstract
UNLABELLED Exposure to high oxygen concentration produces toxicity by free radical release. We aimed to study: whether stable chronic obstructive pulmonary disease (COPD) patients present an unbalance in the blood redox status; the effect of oxygen administration on blood redox balance; the efficacy of N-acetyl-cysteine (NAC) treatment against the oxidative stress-induced by oxygen administration and whether it is dose-related. To this, 45 stable state III COPD patients were recruited and reduced glutathione (GSH) and oxidised glutathione (GSSG) in erythrocytes and thiol proteins (P-SH) and carbonyl proteins (PC) in both erythrocytes and plasma were evaluated. All COPD patients underwent 2 l/m oxygen for 18 h and NAC at 1200 or 1800 mg/day or placebo for 48 h starting with oxygen administration. Blood samples were collected at basal conditions, after 8 and 18 h of oxygen administration and 24 h after oxygen withdrawal. RESULTS COPD patients present an unstable redox equilibrium mainly due to plasma sulphydryl protein depletion. Oxygen administration oxidize erythrocyte GSH, decrease P-SH and increase PC levels in both plasma and erythrocytes. NAC administration counteract the oxidative stress and at the highest dose completely prevent protein oxidation. In conclusion, stable state III COPD patients present an unstable redox balance; long term low flow oxygen administration induces systemic oxidative stress, which is prevented by NAC treatment.
2.
A randomized controlled trial of mist in the acute treatment of moderate croup.
Neto, GM, Kentab, O, Klassen, TP, Osmond, MH
Academic emergency medicine : official journal of the Society for Academic Emergency Medicine. 2002;(9):873-9
Abstract
OBJECTIVE To determine whether the use of mist improves clinical symptoms in children presenting to the emergency department (ED) with moderate croup. METHODS Children 3 months to 6 years of age were eligible for the study if they presented to the ED with moderate croup. Moderate croup was defined as a croup score of 2-7. The patients were randomly assigned to receive either mist (humidified oxygen) via mist stick or no mist. The patients had croup scores measured at baseline and every 30 minutes for up to two hours. At these intervals the following parameters were also measured: heart rate, respiratory rate, oxygen saturation, and patient comfort score. The patients were treated until the croup score was less than 2 or until two hours had elapsed. All patients initially received a dose of oral dexamethasone (0.6 mg/kg). Other treatments, such as racemic epinephrine or inhaled budesonide, were given at the discretion of the treating physician. The research assistants were unaware of the assigned treatments. RESULTS There were 71 patients enrolled in the study; 35 received mist and 36 received no mist. The two treatment groups had similar characteristics at baseline. The median baseline croup score was 4 in both groups. The outcomes were measured as the change from baseline at 30, 60, 90, and 120 minutes. The change in the croup score from baseline in the mist group was not statistically different from the croup score change in the group that did not receive mist (p = 0.39). There was also no significant difference in improvement of oxygen saturation, heart rate, or respiratory rate at any of the assessment times. There was no adverse effect from the mist therapy. CONCLUSIONS Mist therapy is not effective in improving clinical symptoms in children presenting to the ED with moderate croup.