title: Paradoxical changes in brain natriuretic peptide levels and loading conditions after intravenous conscious sedation.
abstract: BACKGROUND
  Elevated filling pressure and wall stress have been proposed as stimuli for elevated brain natriuretic peptide (BNP) levels. Narcotic and benzodiazepine sedation, such as is used for transesophageal echocardiography (TEE), is known to decrease filling pressures. We hypothesized that lower filling pressure and wall stress associated with intravenous conscious sedation (IVCS) would lead to lower BNP levels.
  
  
  METHODS
  We studied BNP levels, blood pressure, and echocardiographic indices of filling pressure and wall stress before and after IVCS and TEE.
  
  
  RESULTS
  When data before and after IVCS and TEE were compared, mean blood pressure decreased (149 +/- 24/83 +/- 14 mm Hg vs 126 +/- 29/69 +/- 14; P < .01), as did mitral Doppler E wave velocity (82 +/- 23 cm/s vs 76 +/- 22; P < .05), right ventricular/atrial gradient (31 +/- 10 mm Hg vs 29 +/- 13; P < .05), and wall stress. However, BNP levels increased (195 +/- 407 pg/mL vs 238 +/- 458; P < .01).
  
  
  CONCLUSIONS
  In a series of patients undergoing clinically indicated TEE, BNP levels increase above baseline after IVCS. The increase in BNP occurs despite lower blood pressure, lower mitral Doppler E velocity, lower right ventricular/atrial gradient, and lower wall stress compared with baseline. The mechanism of the paradoxical increase in BNP is not entirely clear, but it may conceivably be a result of counterregulatory hormone release caused by acute decrease in blood pressure.
authors.affiliation: Division of Cardiology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA.
authors.forename: Craig S
authors.initials: CS
authors.lastname: Vinch
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Hill
authors.forename: Giridhar
authors.initials: G
authors.lastname: Logsetty
authors.forename: Dennis A
authors.initials: DA
authors.lastname: Tighe
authors.forename: Theo E
authors.initials: TE
authors.lastname: Meyer
authors.forename: Gerard P
authors.initials: GP
authors.lastname: Aurigemma
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001795:Blood Pressure Determination / Q000379:methods; D016292:Procedural Sedation; D017548:Echocardiography, Transesophageal; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects*; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D018709:Statistics, Nonparametric
chemical_list: D020097:Natriuretic Peptide, Brain