Fluid overload at start of continuous renal replacement therapy is associated with poorer clinical condition and outcome: a prospective observational study on the combined use of bioimpedance vector analysis and serum N-terminal pro-B-type natriuretic peptide measurement
Research
National Clinical Research Center of Kidney Disease, Jinling Hospital, Nanjing University School of Medicine, Nanjing 210016, P. R. China
Critical Care 2015, 19:135Â
doi:10.1186/s13054-015-0871-3
Published: 2 April 2015
Abstract (provisional)
Introduction It is unclear whether the fluid status, as determined by bioimpedance
vector analysis (BIVA) combined with serum N-terminal pro-B-type natriuretic peptides
(NT-pro-BNP) measurement, is associated with treatment outcome among patients receiving
continuous renal replacement therapy (CRRT). Our objective was to answer it. Methods
Patients in the intensive care units of an university teaching hospital requiring
CRRT were screened for enrollment. For the enrolled patients, BIVA and serum NT-pro
BNP measurement were performed just before the start of CRRT and 3 days afterward.
According to the BIVA and NT-pro BNP measurement results, the patients were divided
into four groups according to fluid status type: type 1, both normal; type 2, normal
BIVA results and abnormal NT-pro BNP levels; type 3, abnormal BIVA results and normal
NT-pro BNP levels; type 4, both abnormal. The associations between fluid status and
outcome were analyzed. Results Eighty-nine patients were enrolled, with 58 males and
a mean age of 49.0 ± 17.2 years. The mean score of acute physiology and chronic health
evaluation II (APACHE II) was 18.8 ± 8.6. The fluid status before CRRT start was as
follows: type 1, 21.3% (19/89); type 2, 16.9% (15/89); type 3, 11.2% (10/89); and
type 4, 50.6% (45/89). There were significant differences between fluid status types
before starting CRRT on baseline values for APACHE II scores, serum creatinine, hemoglobin,
platelet count, urine volume, as well as incidences of oliguria and acute kidney injury
(p lt; 0.05). There were significant differences between patients with different
fluid status before CRRT start on hospital mortality: type 1, 26.3% (5/19); type 2,
33.3% (5/15); type 3, 40% (4/10); and type 4, 64.4% (29/45) (p = 0.019); as well as
renal function recovery rates: type 1, 57.1% (4/7); type 2, 67.7% (6/9); type 3, 50%
(3/6); and type 4, 23.7% (9/38) (p = 0.051). Conclusions Fluid status abnormalities
were common among patients receiving CRRT. Different types of fluid status distinguished
by BIVA combined with serum NT-pro BNP measurements corresponded to different clinical
conditions and treatment outcomes, which implies a value of this method for evaluation
of fluid status among patients receiving CRRT.