The following is the summary of “Non-interventional follow-up versus fluid bolus in RESPONSE to oliguria in hemodynamically stable critically ill patients: a randomized controlled pilot trial” published in the December 2022 issue of Critical care by Inkinen, et al.

A typical technique is fluid bolus therapy to increase the amount of urine produced. There is still debate over whether or not a fluid bolus is beneficial for treating oliguria, as most of the available data comes from observational research. Patients who were hemodynamically stable but had oliguria for at least 2 hours (urine output <0.5 mL/kg/h) were randomly assigned to either a follow-up strategy with no fluid bolus or a 500 mL fluid bolus, and the effect on urine output was compared. Researchers randomly assigned 130 patients to either non-interventional follow-up (FU) for 2 h or a 500 mL crystalloid fluid bolus (FB) over 30 min. 

The primary outcome was the rate at which patients’ urine output doubled, as measured by the ratio of urine output in the 2 hours after randomization to that in the 2 hours before. Two-tailed regression was employed to account for the stratification variables (presence of sepsis or AKI) in the final results. The odds ratios investigators calculated were then transformed into risk ratios (RR) and accompanied by 95% CI. Finally, mean, or median regression was used to compare the continuous variables between the 2 groups, and the difference was then represented as a percentage with a 95% CI. Altogether During the 2 hours, the urine output of 10 (15.9%) of the 63 patients in the FU group and 22 (32.8%) of the 67 patients in the FB group quadrupled, RR (95% CI) 0.49 (0.23-0.71), P=0.026.

 Individuals in the FU group had a median [IQR] change in urine output of -7 [ -19 to 17] mL after 2 hours compared to pre-randomization levels, while those in the FB group had a median [IQR] change in output of 19 [0-53] mL after the same time period, for a median difference (95% CI) of -23 [ -36 to -10] mL, P=0.001. The median (95%CI) difference in the duration of oliguria between the FB and FU groups was 2 hours (IQR: 0-4), and the P=0.038. Compared to the FB group, the FU group had a lower median [IQR] cumulative fluid balance on the day of the study (678 [518-1029] mL vs. 1,071 [822-1505] mL; median difference (95% CI) -387 [-635 to -213] mL, P<0.001]. The cumulative fluid balance of oliguric patients was lower when a follow-up strategy was used rather than a fluid bolus of 500 mL crystalloid.

Source: ccforum.biomedcentral.com/articles/10.1186/s13054-022-04283-8