Study On The Correlation Between Plasma NT-proBNP Level And Intrathoracic Blood Volume Index In Acute Heart Failure Patients

Acute heart failure is a syndrome that filling and ejecting ability of heart is compromised by organic or functional disease. It's common in critical illnesses.Volume overload is one of the predisposing factors which cause and exacerbate heart failure. Monitoring the change of preload, knowledge about AHF patients'heart function and hemodynamic state in time are helpful to evaluate and treat patients at the early stage. Pulse-induced contour cardiac output(PICCO) is the combination of the transpulmonary thermodilution technique and artery pulse contour analysis technique.Different from traditional thermodilution catheter which evaluates the global heart by measuring parameters of the right heart,PICCO acquires the data on the global heart from the temperature-time curve in aorta,by injecting cold saline through central venous catheter.Compared with the Swan-Ganz catheter technique,ITBVI from PICCO is more reliable, stable,and accurate to evaluate the preload,affected little by respiration. Currently,ITBVI is recommended as a sensitive parameter of preload,better than PCWP and CVP.NT-proBNP is a peptide hormone,emitted by myocardial cell,is very helpful to early diagnose,evaluate severity and prognosis.Intraventricular pressure and ventricular wall tension increase as volume stress increases,which causes myocardium to synthesize and emit NT-pro BNP.As AHF is present,volume and stress are overloaded,and the ventricular wall tension increases,which causes the increase of the NT-proBNP level.Since ITBVI is a sensitive para- meter of preload,we suggest that plasma BNP level is related to ITBVI.By far,studies on the correlation between plasma NT-proBNP level and intrathoracic blood volume index in acute heart failure patients are seldom reported domestically.ObjectiveWe study the correlation between plasma NT-proBNP level and intrathoracic blood volume index in acute heart failure patients, assess the clinic meaning of plasma BNP level in AHF patients,to search for a way to evaluate patients'condition fast and accurately,assess patients'hemodynamic state to direct medicine usage and fluid management,increase curative effect.Data and methodsAHF patients received heart function grading when admitted into ICU, NYHA grading system for AHF patients with chronic heart dysfunction history, Killip grading system for AHF patients caused by acute myocardium infarction. Patients NYHA≥III or Killip≥II,totally 36 cases,received PICCO monitoring. ITBVI was measured and plasma NT-proBNP was checked respectively at 1 hour, 24 hour,and 48 hour after admission. Correlation between ITBVI and plasma NT-proBNP level was analyzed through statistic methods.ResultsNT-proBNP increased as ITBVI increased,NT-proBNP correlates with ITBVI positively(r=0.701,p<0.05).stroke volume index(SVI,ml/㎡) correlates negatively with NT-proBNP ( r=-0.405,P < 0.05 ) .The higher the NT-proBNP,the lower the SVI.Correlations between CVP and NT-proBNP(r=0.182,p>0.05),ITBVI (r=0.054,p>0.05) were not found.ConclusionsIn AHF patients,the higher NT-proBNP,the worse heart function,the greater the risk of volume overload.It's not accurate to assess volume overload according to CVP alone.