Precursors to oliguria during major burn resuscitation: an analysis of a prospective observational trial at 5 major US burn centers

Currently, urine output is the leading variable used to tailor fluid resuscitation in patients with large TBSA burns. However, this metric often lags with respect to resuscitation. Our group sought to identify derangements in variables that precede development of oliguria (<30 cc/hr) that we hypothesize will aid in more efficient resuscitation. We performed a retrospective analysis of 146 adult patients admitted within 4hours of a large TBSA (>20%) burn. We then divided them into two cohorts: those who developed oliguria within 6hours of admission and those who did not. Patients who experienced early oliguria had a higher incidence of invasive SBP <90 (p=0.02) or DBP <40 (p=0.009), lower minimum bicarbonate level (p=0.04), more full thickness burns (p=0.004), and higher TBSA (p=0.01). There were more female patients in the oliguric group (p=0.003). Multivariate analysis was used to develop a model to predict development of oliguria. When evaluated together, minimum DBP, sex, TBSA (or percent full thickness burn), and maximum base deficit constituted the most parsimonious model that significantly predicted oliguria (AUC = 0.92). Interestingly, the model lost significance when DBP was omitted, highlighting the importance of diastolic pressure in the development of oliguria.