Is proBNP a Reliable Marker for the Evaluation of Fluid Load in Patients Undergoing Continuous Renal Replacement Therapy?

Aim: Pro-B type natriuretic peptide (proBNP) has been defined as a volume marker in hemodialysis patients. In the present study we aimed to evaluate the role of serum proBNP levels to indicate fluid load in patients undergoing continuous renal replacement therapy (CRRT) due to overhydration. Material and Method: Patients who were admitted to a tertiary 7-bed pediatric intensive care unit and underwent CRRT due to overhydration were included in the study. Results: The study was conducted with 15 girls (53.6%) and 13 boys (46.4%). The mean age was 61.46±56.13 months (range, 2-183 months); the mean CRRT administration time was 20.8±14.9 hours (range, 5-60 hours); and the mean percentage of fluid extracted from the body was 8.43 ± 4.51% (range, 2.5-20%). CRRT was administered to 12 patients because of fluid overload (42.9%) and to 12 (57.1%) because of fluid load accompanied by uremia.. There was a statistically significant difference between body weight, urea, and creatinine levels of patients before and after treatment (p= 0.001). The mean proBNP level was 23.306 ± 13.943 pg/mL immediately before CRRT and the mean proBNP after CRRT was 22.178 ± 15.473 pg/mL. There was no statistically significant difference between the initial and final proBNP levels (p= 0.756). With the exception of serum sodium levels, there was no correlation between the final proBNP levels and body weight, urea, and creatinine (p>0.05). Similarly, there was also no correlation between initial proBNP levels and fluid load (p= 0.602) or between the percentage of extracted fluid and final proBNP levels (p= 0.155). Discussion: There was no significant correlation between the fluid load and initial proBNP levels or with the extracted fluid percentage and final proBNP levels in patients undergoing CRRT because of fluid overload.In conclusion, no appropriate marker was determined to evaluate cumulative fluid load and the extracted liquid volume