Comparison of analytical performance of i-Smart 300 and pHOx ultra for the accurate determination of pleural fluid pH.

BACKGROUND: Pleural fluid pH is an essential test for diagnosing complicated parapneumonic effusion. We evaluated the performance of two blood gas analyzers in measuring pleural fluid pH. METHODS: The i-STAT G3+ (Abbott) was used as a reference analyzer to evaluate the pH values obtained from other methods: the i-Smart 300 (i-SENS), the pHOx Ultra (Nova Biomedical), using a clot catcher to filter off microclot, and pH indicator paper. Within-device precision was performed using quality control materials. We compared pleural fluid pH (n = 86) by the above methods and analyzed the concordance rate at the level of the medical decision point, pH 7.2. RESULTS: The within-device coefficient of variations of pH were below 0.1% for all blood gas analyzers tested. The slopes of the regression equations for the i-Smart 300, pHOx Ultra, and pH indicator paper against the reference analyzer were 0.850 (95% confidence interval, CI, 0.800-0.896), 0.714 (95% CI, 0.671-0.766), and 1.105 (95% CI, 0.781-1.581), respectively. The kappa values for the i-Smart 300, pHOx Ultra, and pH indicator paper against the reference analyzer were 0.883 (95% CI, 0.656-1.110), 0.739 (95% CI, 0.393-1.084), and 0.464 (95% CI, 0.102-0.826), respectively. CONCLUSIONS: The i-Smart 300 and pHOx Ultra demonstrated good analytical performance and diagnostic accuracy when determining pleural fluid pH compared with that by the i-STAT G3+, whereas the pH indicator paper showed unsatisfactory results.

[Reduction of the platelet transfusion dose and its effects].

BACKGROUND: In Korea, a platelet transfusion dose (TD) of 8 units of platelet concentrates (PC) is usually used. To minimize the shortage of blood products and transfusion-related adverse reactions, the TD has been changed from 8 to 6 units in 2006 in our hospital. Here, we analyzed the dose reduction effect on patients' platelet counts and transfusion frequency. METHODS: We compared the amount of issued PC, platelet counts before and after transfusion, post-transfusion platelet increments, and transfusion frequencies in patients who were transfused with 8 PC in 2006 and 6 PC in 2008. RESULTS: Despite an increase in the number of admitted patients by 20% in 2008 with a disease distribution similar to that in 2006, the number of issued PC in 2008 was decreased by 26.6% compared to that in 2006. In 2008, post-transfusion platelet counts, pre-transfusion platelet counts in patients transfused with 320 mL whole blood-derived PC, and platelet increments in patients transfused with 400 mL whole blood-derived PC were significantly decreased. However, the mean transfusion frequency per one month was not significantly different, 4.3 times in 2006 and 4.7 in 2008. CONCLUSIONS: By implementing a policy of platelet TD restriction, the amount of total issued PC was markedly decreased. Although post-transfusion platelet counts were decreased, the transfusion frequency in a month was not significantly increased. The restriction of platelet TD was helpful for increasing physicians' recognition of blood shortage while achieving similar transfusion effects. We conclude that 6 units of PC would be a better guideline for the platelet TD.