INTRODUCTION
Several studies have demonstrated that pre-transplant pulmonary function metrics in patients undergoing hematopoietic stem cell transplant (HSCT), including the diffusing capacity for carbon monoxide corrected for hemoglobin (DLCOHgb), are associated with early respiratory failure and lower overall survival[1-3]. A variety of algorithms have been developed to use pulmonary function tests (PFTs) as a way to predict post-transplant pulmonary complications [4, 5]. DLCOHgb is a large part of these algorithms. There are two equations used to correct DLCO for hemoglobin (Hgb), the Dinakara[6] and Cotes[7] equations. At this it is unknown if one is superior to the other in regard to predicting morbidity and mortality in the pediatric stem cell transplant population.
There has yet to be a study directly comparing the ability of the Cotes and the Dinakara equations to predict morbidity and mortality following stem cell transplant in a pediatric population. Given that previous studies have corrected DLCO for hemoglobin inconsistently and have used different equations, determining if using the Dinakara or Cotes equations leads to statistically and clinically significant differences in this population could change the way physicians counsel patients and families prior to stem cell transplant. [4, 5, 8]
The objective of this study is to compare the Dinakara and Cotes equations in their ability to predict post HSCT pulmonary complications and mortality. We hypothesize that because the Cotes equation is more widely used, the pre-transplant diffusing capacity adjusted for Hgb by the Cotes equation in pediatric patients undergoing HSCT will predict morbidity and mortality more accurately than the Dinakara equation following HSCT.