Thiol-disulfide homeostasis and ischemia-modified albumin levels as indicators of oxidative stress in welders' lung disease.

Welders' lung disease refers to mixed exposure to different kinds of metals and chemicals from welding fumes, which affect all parts of the respiratory tract including airways and parenchyma together. This study aimed to investigate the oxidative status in patients with welders' lung (PWL) by means of thiol-disulfide homeostasis and ischemia-modified albumin (IMA) levels. The male welder workers diagnosed with welders' lung disease and healthy individuals were recruited in the study. Plasma levels of disulfide, disulfide/native thiol ratio, disulfide/total thiol ratio, IMA, and catalase (CAT) were determined. Pulmonary function test parameters of both groups were compared. The thiol-disulfide homeostasis parameters of PWL and control group were as follows: disulfide (20.5 ± 6.3 vs. 16.2 ± 3.9 µmol L-1, p < 0.001), disulfide/native thiol (4.36 (1.59) vs. 4.0 (1.64), p = 0.024), and disulfide/total thiol (4.01 (1.34) vs. 3.71 (1.41), p = 0.024). IMA levels in PWL were significantly higher than the control group (1.37 (0.27) mg dL-1 vs. 0.49 (0.61) mg dL-1, p < 0.001), whereas CAT activities were significantly higher in the control group (106.6 (54.5) kU L-1 vs. 78.3 (67.8) kU L-1, p = 0.003). The findings of the present study revealed that oxidative stress plays a key role in the pathogenesis of welders' lung disease. Plasma thiol-disulfide homeostasis and IMA levels might be indicators of oxidative stress in PWL.

Comparison of the serial surveillance with quantitative and non-quantitative tracheal aspirate in predicting ventilator-associated pneumonia etiology in patients receiving antibiotic therapy.

BACKGROUND: The aim of this study was to investigate the value of serial quantitative (QC) and non-quantitative (NQC) endotracheal aspirate (ETA) surveillance cultures in predicting the causative pathogen of ventilator associated pneumonia (VAP) in patients receiving antibiotic therapy and the factors associated with their predictive value. This was a prospective observational cohort study carried out in the Intensive Care Unit of a tertiary hospital. METHODS: The study enrolled 109 patients receiving mechanical ventilation for at least four days. Tracheal surveillance cultures were obtained routinely thrice weekly. Each sample was processed non-quantitatively and quantitatively (103 and 105 cfu/mL). The sensitivity, specificity and predictive values (true positives plus true negatives) of these cultures for the development of VAP were evaluated, and the causative pathogens were assessed. RESULTS: Sixty-eight VAP episodes were detected during this period. The NQCs and QCs detected the responsible pathogens of VAP in 63% and 28% of the VAP patients, respectively. Surveillance with NQC and QC were negative in 78% and 85% of the patients without VAP, respectively. Compared with the QC-ETAs (47%), NQC-ETAs (65%) were more predictive in all of the 109 patients. The NQC-ETA and QC-ETA predicted the causative pathogens at 3.3+/-2.7 days and 2.5+/-1.7 days prior to the development of VAP episodes, respectively. Both NQC and QC surveillance cultures were less predictive in older patients, and QCs were less predictive in A. baumannii infections. CONCLUSION: These results suggest that surveillance with NQ-ETA is better than the Q-ETA in predicting the development and causative pathogen of VAP in patients who have already been receiving antibiotic therapy.