title: Power Doppler sonography of the kidney: effect of Valsalva's maneuver.
abstract: OBJECTIVE
  It has been reported that an intra-abdominal pressure (IAP) above 15 mm Hg may cause oliguria and that an IAP above 25 mm Hg may cause anuria. Because Valsalva's maneuver yields an IAP exceeding 180 mm Hg, it is presumed to affect renal perfusion. We evaluated the ability of power Doppler sonography to depict the changes in renal blood flow during Valsalva's maneuver.
  
  
  METHODS
  Seven healthy men aged 21-24 years and 1 50-year-old man with massive ascites participated in the study. With each healthy subject lying in a supine position, longitudinal power Doppler sonograms of the kidney were obtained and analyzed semiquantitatively during Valsalva's maneuver. Also, in the patient with massive ascites, power Doppler sonography was performed before and after paracentesis.
  
  
  RESULTS
  Along with an increase in IAP, monitored as expiratory pressure during Valsalva's maneuver, power Doppler signals decreased as indicated by both visual impression and computer scores. In the patient with massive ascites, signal intensity increased after paracentesis.
  
  
  CONCLUSIONS
  Our results demonstrated that an increase in IAP within the physiologic range affects renal perfusion and that power Doppler sonography depicts semiquantitatively the change in renal blood flow.
authors.affiliation: Department of Nephrology, Jichi Medical School Hospital, Yakushiji 3311-1, Minamikawachi-machi, Kawachi-gun, Tochigi 329-0431, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Takano
authors.forename: Y
authors.initials: Y
authors.lastname: Ando
authors.forename: N
authors.initials: N
authors.lastname: Taniguchi
authors.forename: K
authors.initials: K
authors.lastname: Itoh
authors.forename: Y
authors.initials: Y
authors.lastname: Asano
mesh_terms: D000328:Adult; D006801:Humans; D007668:Kidney / Q000098:blood supply* / Q000000981:diagnostic imaging*; D008297:Male; D012039:Regional Blood Flow; D012680:Sensitivity and Specificity; D018608:Ultrasonography, Doppler; D014636:Valsalva Maneuver