title: Changes in B-type Natriuretic Peptide and Related Hemodynamic Parameters Following a Fluid Challenge in Critically Ill Patients with Severe Sepsis or Septic Shock.
abstract: BACKGROUND
  Severe sepsis or septic shock.
  
  
  OBJECTIVE
  The aim of this study is to examine the effect of a fluid challenge on the B-type natriuretic peptide (BNP) and the hemodynamic state.
  
  
  METHODS
  This observational study was conducted in an intensivist-led academic, mixed medical-surgical Intensive Care Unit.
  
  
  METHODS
  Focused transthoracic echocardiogram, plasma BNP, and hemodynamic measurements were recorded at baseline and following a 500 ml fluid challenge in thirty patients. Independent predictors of the percentage (%) change in stroke volume (SV) were sought. Next, these independent predictors were assessed for a relationship with the percentage change in BNP.
  
  
  METHODS
  Multiple linear regressions, Wilcoxon rank-sum test,t-test, and Pearson's correlation were used. Data analysis was carried out using SAS. The 5% significance level was used.
  
  
  RESULTS
  Using a multiple regression models, the percentage increase in SV was independently predicted by the percentage increase in mean arterial pressure, left ventricular end-diastolic volume/dimension (LVEDV/LVEDd), ejection fraction, and a decrease in Acute Physiology and Chronic Health Evaluation II score (P< 0.0001). Preload, measured using LVEDV1 (before the fluid challenge) was significantly larger in the fluid nonresponders (%SV increase <15%) vs. the responders (%SV increase ≥15%). Finally, the percentage change in BNP was positively correlated with left ventricular size at end diastole LVEDd,r= 0.4,P< 0.035).
  
  
  CONCLUSIONS
  An increase in BNP soon after a fluid challenge may have some predictive utility of a large LVEDd, which in turn can be used to independently predict the SV response to a fluid challenge.
authors.affiliation: Division of Critical care, Intensive Care Unit, Chris Hani Baragwanath Academic Hospital, University of Witwatersrand, Johannesburg, South Africa.
authors.forename: Shahed
authors.initials: S
authors.lastname: Omar
authors.affiliation: Division of Critical care, Intensive Care Unit, Chris Hani Baragwanath Academic Hospital, University of Witwatersrand, Johannesburg, South Africa.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Ali
authors.affiliation: Division of Critical care, Intensive Care Unit, Chris Hani Baragwanath Academic Hospital, University of Witwatersrand, Johannesburg, South Africa.
authors.forename: Yahya
authors.initials: Y
authors.lastname: Atiya
authors.affiliation: Division of Critical care, Intensive Care Unit, Chris Hani Baragwanath Academic Hospital, University of Witwatersrand, Johannesburg, South Africa.
authors.forename: Rudo Lufuno
authors.initials: RL
authors.lastname: Mathivha
authors.affiliation: Department of Intensive Care Medicine, Royal Brisbane and Women's Hospital, The Burns, Trauma and Critical Care Research Centre, The University of Queensland, Brisbane, Australia.
authors.forename: Joel M
authors.initials: JM
authors.lastname: Dulhunty
keywords: B-type natriuretic peptide; critically ill; fluid challenge; hemodynamic; intensive care; sepsis; severe sepsis; shock