This study isn't something that can be translated directly into new recommendations for patient care; nonetheless, it's one of the more elegant studies I've reviewed in recent years.
Source: Kantor DB, Hirshberg EL, McDonald MC, et al. Fluid balance is associated with clinical outcomes and extravascular lung water in children with acute asthma exacerbation [published online ahead of print January 9, 2018]. Am J Respir Crit Care Med. doi:10.1164/rccm.201709-1860OC. See AAP Grand Rounds commentary by Dr. Susan Bratton (subscription required).
The study combines both retrospective and prospective cohort studies with conclusions that virtually lay out the parameters for designing prospective randomized controlled trials that could lead to changes in clinical practice. With apologies to Ms. Browning, let me count the ways I love this study.
1. It's really a couple studies combined into 1 report, with both a retrospective and a prospective observational component. The retrospective findings informed the look forward prospectively and also helped check for some of the inaccuracies (like accurate measurement of fluid ins and outs) in the retrospective cohort.
2. The authors made room for another study component that would lend some degree of biologic plausibility to their findings. Specifically, they wanted to gather support for the hypothesis that highly negative intrapleural inspiratory pressures in asthmatics might cause fluid to move from the intravascular compartment into lung tissue, thereby impairing respiratory function. Any excessive fluid administration could then cause worsening of the asthma exacerbation. Their findings make a compelling argument for this hypothesis.
3. The description of study limitations (6 in all) is excellent. This portion of a research report often is a sort of collaboration between the researchers and the journal reviewers and editors. They all deserve kudos for putting the study findings into perspective.
Clinicians who provide care for children with severe (requiring hospitalization) asthma exacerbations would benefit from reading this study; perhaps they will think twice about being too cavalier in administering intravenous fluid boluses in this setting. For the general pediatric provider outside of hospital emergency departments and inpatient units, however, the value of reading the study is more to appreciate how incrementally collected and analyzed data could be used to blaze a path to a more definitive trial. I hope someone is working on that trial right now!
