Diffusion Capacity in Tropical Eosinophilia

To reply to the criticism of Drs Dobkin and Yeston, we first note that it is based on a previously published report by them and others,' which concluded that pH paper lacks clinical accuracy in guiding prophylaxis for stress gastritis and that reliance on its use would lead to a significant incidence of undertreatment. In two other studies, however, intragastric pH monitored continuously with an indwelling intragastric pH probe correlated well with that determined by using pH paper, the correlation coefficients in these studies ranging from 0.71k to 0.95.@ These values agree with our data showing a correlation of 0.98.@ Interestingly, intragastric pH determined continuously with a disposable sensor did not correlate as well with gastric pH determined by aspiration and a calibrated laboratory pH meter (r= 0.68).@ The discrepancy in pH determination between a standard labo ratory pH meter and paper indicator that Dobkin et al' reported is likely due to the time course of the testing. Although pH was determined by paper immediately after gastric samples were collected, samples for pH electrode measurement were analyzed after a delay of 24 to 36 h. Surely, within this interval, various components ofgastric juice would have degraded and decomposed, which would have influenced pH (a pH change of —¿ 0.08 to 0.38 at 24 h was reported). Also, none of their patients suffered any detectable gastrointestinalhemorrhage(possiblya reflectionof the effectiveness of prophylaxis?) even though sensitivity was 66.7 percent and episodes of “¿ undertreatment― occurred in 63 percent ofpatients when the paper indicator was used to guide therapy. In this case, the clinical relevance of a statistically significant difference is questionable. Although analysis of gastric pH with a pH electrode serves as the “¿ gold standard,― recent data@showed wider variability in readings from a continuous intragastric electrode than from a standard laboratory pH meter. Which one, then, is the “¿ gold standard―?Presently, the standard clinical practice in deter mining gastric pH as a guide to prophylaxis and therapy is still pH paper. Unlessfurther studies showits use to be obsolete,and until the queston ofwhich pH electrode (continuous versus intermittent) is more accurate is answered, it is premature to discount the paper indicator as a reliable method for determining gastric pH.