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Background:Results of arterial blood gas analysis can be biased by pre-analytical factors, such as time interval before analysis, temperature during storage and syringe type.Objectives:To investigate the effects of samples storage temperature and time delay on blood gases, bicarbonate and PH results in human arterial blood samples.Patients and Methods:2.5 mL arterial blood samples were drawn from 45 patients via an indwelling Intraarterial catheter. Each sample was divided into five equal samples and stored in multipurpose tuberculin plastic syringes. Blood gas analysis was performed on one of five samples as soon as possible. Four other samples were divided into two groups stored at 22°C and 0°C. Blood gas analyses were repeated at 30 and 60 minutes after sampling.Results:PaO2 of the samples stored at 0°C was increased significantly after 60 minutes (P = 0.007). The PaCO2 of the samples kept for 30 and 60 minutes at 22°C was significantly higher than primary result (P = 0.04, P < 0.001). In samples stored at 22°C, pH decreased significantly after 30 and 60 minutes (P = 0.017, P = 0.001). There were no significant differences in other results of samples stored at 0°C or 22°C after 30 or 60 minutes.Conclusions:In samples stored in plastic syringes, overestimation of PaO2 levels should be noted if samples cooled before analysis. In samples stored in plastic syringes, it is not necessary to store samples in iced water when analysis delayed up to one hour.

Background:The use of computed tomography pulmonary angiography (CTPA) has been increased during the last decade.Objectives:We studied the adherence to current diagnostic recommendations for evaluation of pulmonary embolism in a teaching hospital of Tehran University of Medical Sciences.Patients and Methods:The registered medical records (Wells scores and serum D-dimer level) of all patients whose CTPA was performed with suspicion of pulmonary thromboembolism (PTE) were studied retrospectively. Modified Wells score of each patient was determined without being aware of the CTPA results. The patients were categorized to those with a high (likely) clinical probability (score > 4) and low (unlikely) clinical probability (score≤ 4) of PTE.Results:During a 6-month period, 82 patients who underwent CTPA were included. The prevalence of PTE was 62.2% in the group of subjects with a likely clinical risk. In 45 (54.8%) of those patients whose CTPA was requested, the PTE was unlikely based on modified Wells criteria. In the clinically unlikely group, serum D-dimer assay was done in 15 out of 45 (33.3%), while it was inappropriately checked in 10 out of 37 (27.0%) with a clinically likely risk. General adherence rate to diagnostic algorithm of PTE was 43.9%.Conclusion:There is still excessive unjustified concern of PTE in less trained physicians leading to excessive diagnostic work-up. Loyalty to the existing guideline for management of suspected PTE in educational hospitals and supervision of attending physicians could prevent overuse of CTPA.

Background: The precise head to head relationships between Cardio-pulmonary exercise testing (CPET) parameters and patients' daily symptoms/activities and the disease social/emotional impact are less well defined. In this study, the correlation of COPD daily symptoms and quality of life [assessed by St. George's Respiratory Questionnaire (SGRQ)] and COPD severity index (BODE-index) with CPET parameters were investigated. Methods: Symptom-limited CPET was performed in 37 consecutive COPD (GOLD I-III) subjects during non-exacerbation phase. The SGRQ was also completed by each patient. Results: SGRQ-score correlated negatively with FEV1 (r=−0.49, P<0.01), predicted maximal workrate (%WR-max) (r=−0.44, P<0.01), V'O 2 /WR (r=−0.52, P<0.01) and breathing reserve (r=−0.50, P<0.01). However it did not correlate with Peak-V'O 2 % predicted (r=−0.27, P=0.10). In 20 (54.1%) subjects in which leg fatigue was the main cause for stopping the test, Peak-V'O 2 , %WR-max, HR-Reserve and Breathing reserve were higher (P=0.04, <0.01, 0.04 and <0.01 respectively) than the others. There was also a significant correlation between BODE-index and ∆VO 2 /∆WR (r=−0.64, P<0.001) and breathing-reserve (r=−0.38, P=0.018). Conclusions: The observed relationships between CPET parameter and daily subjective complaints in COPD were not strong. Those who discontinued the CPET because of leg fatigue were in the earlier stages of COPD. Significant negative correlation between ∆VO 2 /∆WR and BODE-index suggests that along with COPD progression, regardless of negative past history, other comorbidities such as cardiac/musculoskeletal problems should be sought. Although more difficult to use than other tools such as COPD Assessment Test (CAT) or COPD Clinical Questionnaire (CCQ) during routine daily practice (6), the St. George's Respiratory Questionnaire (SGRQ) is one of the most widely used self-complete measures in research for assessing patients' symptoms, activities and quality of life (7,8). Along with this subjective measurement, functional capacity in COPD could be measured by objective tools such as cardio-pulmonary exercise testing (CPET) or 6-min walk distance (6MWD) (9-11). Considering the fact that at rest physiologic variable such as pulmonary diffusing capacity for carbon monoxide (DLCO), body mass index (BMI) or even forced expiratory volume in one second (FEV1) could not solely predict exercise intolerance, CPET has been proposed as the gold standard for evaluating the exercise intolerance in patients with pulmonary diseases, including COPD (12). But the precise head to head comparisons of CPET variable with patients' daily symptoms/activities and the disease social/ emotional impact are less well defined. In one study among 129 COPD subjects with GOLD stage II and III, there was at best a weak correlation between Peak-V'O 2 (maximum oxygen uptake) % predicted and some sub-domains of health status (13). While in another study Peak-V'O 2 was to some extent a predictor of physical function (r 2 increased by 0.109) and health-related ...

Pseudomonas aeruginosa is an uncommon cause of community-acquired pneumonia in immune-competent hosts. It is commonly seen in patients with structural lung abnormality such as cystic fibrosis or in immune compromised hosts. Here, the authors report a case of community-acquired Pseudomonas pneumonia in a 26-year old healthy man who presented with 8-week history of malaise and cough.