To the Editor:
—The article by Scheingraber et al. 1supports the findings of a previous comparison of saline with a balanced salt solution carried out by McFarlane and Lee in 1994. 2The accompanying editorial by Prough and Bidani described this study as a clinical report of the administration of “unusually large volumes of saline.”3The study was, in fact, a randomized-controlled comparison of saline with a balanced salt solution, both of which were administered at 15 ml · kg−1· h−1. This rate of administration was half the rate used by Scheingraber et al. 1McFarlane and Lee studied 30 patients with a mean weight of approximately 60 kg who were undergoing surgery that lasted approximately 200 min; therefore, the mean volume of fluid administered would be approximately 3 l, which cannot be considered “unusually large.” Unfortunately, neither the title of this article nor the key words include the terms “randomized comparison,”“acidosis,” or “hyperchloremia,” which may explain why the article was neglected. The report is completely substantiated by the subsequent article by Scheingraber et al. , 1although the acidosis caused by the administration of the saline solution was less severe because the dose of saline was less. In addition, McFarlane and Lee 2reported that the plasma chloride values had returned to normal after 24 h.
I agree wholeheartedly with the editorial comment 3that the Stewart approach to acid–base balance contributes greatly to understanding these phenomena, and that current thinking is often muddled, as shown by a recent survey 4and the subsequent correspondence. 5Much of this debate, regardless of whether it acknowledges previous studies, fails to properly address the potential harm from hyperchloremia. Some argue that hyperchloremia is harmful, 6whereas others, including the authors of the editorial, consider that hyperchloremia is not harmful, 2but cite no supporting evidence. If hyperchloremia has important adverse effects, why have they not yet become apparent? A recent volunteer study suggests that subjective mental changes can occur more readily after sodium chloride administration. 7A prospective randomized study of clinical outcome may be justified because it is outcome rather than surrogate measures, such as biochemical values, that are of clinical importance.