In the study by Grewal et al1 published in the November 2009 issue of Archives, 62.3% more infants in the normal saline group were hospitalized (13 of 23) than infants in the hypertonic saline group (8 of 23; P = .2). This promising trend probably does not reach statistical significance merely because of the small numbers.
In contrast, a clinical score (CS) is a subjective measurement dependent on the rater's skill. In this study, the raters were not physicians but research assistants, in contrast to physician-raters in the previous positive studies.2- 5 Thus, depending on the skill and experience of the raters, response to therapy using only a CS can be misleading. Moreover, using this CS (RACS), the authors conclude that both intervention groups demonstrated significant improvements, which was attributed to epinephrine (in 2.5 mL of normal saline or 2.5 mL of hypertonic saline). This contrasts with no significant benefit using epinephrine/normal saline alone.2- 6 This substantial improvement if true, attributed to epinephrine in both groups, could mask the possible effect of hypertonic saline. Furthermore, only 2.5 mL of hypertonic saline was used (in only 1.5 inhalations on average), and the CS was measured for only up to 120 minutes postinhalation, in contrast to 4 mL in the hypertonic saline group and 3 to 12 inhalations per day for several days in the previous positive studies.2- 5 Thus, the small amount of hypertonic saline used in this study, the short monitoring time in regard to the CS, and the substantial improvement in CS in both groups weaken the ability of CS to uncover a possible positive effect of hypertonic saline during patients' short stay in the ED. Most telling, this study of 23 infants in each group was powered only to uncover a positive effect but not to demonstrate a null effect (equality).
Avigdor Mandelberg, Israel Amirav. Hypertonic Saline in the Treatment of Acute Bronchiolitis in the Emergency Department. Arch Pediatr Adolesc Med. 2010;164(4):395–397. doi:10.1001/archpediatrics.2010.37