title: A Pilot Assessment of Carotid and Brachial Artery Blood Flow Estimation Using Ultrasound Doppler in Cardiac Surgery Patients.
abstract: OBJECTIVE
  To estimate carotid and brachial artery blood flow with Doppler ultrasound in cardiac surgery patients and relate such estimates to cardiac index, lactate levels, and markers of renal function.
  
  
  METHODS
  A prospective observational study.
  
  
  METHODS
  A teaching hospital.
  
  
  METHODS
  Twenty-five elective cardiac surgery patients.
  
  
  METHODS
  The authors measured bilateral carotid and brachial artery blood flows using Doppler ultrasound and, simultaneously, cardiac index using a pulmonary artery catheter; lactate and serum creatinine levels; and urine output. The relationship between these indices and biomarkers was assessed statistically.
  
  
  RESULTS
  Median carotid arterial blood flow was estimated at 0.323 L/min (interquartile ratio [IQR], 0.256-0.429 L/min) on the right and 0.308 L/min (IQR, 0.247-0.376 L/min) on the left at baseline. Median brachial arterial blood flow was estimated at 0.063 L/min (IQR, 0.039-0.115 L/min) on the right and 0.063 L/min (IQR, 0.039-0.081 L/min) on the left at baseline. There was a weak correlation between right- and left-sided flows (brachial: rho = 0.285; carotid: rho = 0.384) and between brachial and carotid flow (right: rho = 0.135, left: rho = 0.225). There also was a weak correlation between cardiac index and brachial flow (right: rho = 0.215; left: rho = 0.320) and carotid flow (left: rho = 0.159) immediately after surgery, and no correlation 1 day after surgery (right brachial: rho = -0.010; left brachial: rho = -0.064; left carotid: rho = -0.060). There were no significant correlations between carotid or brachial flows and lactate and serum creatinine levels or urine output.
  
  
  CONCLUSIONS
  In cardiac surgery patients, Doppler-estimated carotid and brachial arterial blood flows have only a weak correlation with cardiac index and no correlation with lactate or creatinine levels or urine output. Thus, Doppler estimation of these blood flows cannot be used to provide noninvasive estimates of cardiac index in patients after cardiac surgery.
authors.affiliation: Department of Intensive Care, Austin Hospital, Melbourne, Australia.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Weber
authors.affiliation: Department of Intensive Care, Austin Hospital, Melbourne, Australia.
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Glassford
authors.affiliation: Department of Intensive Care, Austin Hospital, Melbourne, Australia.
authors.forename: Glenn M
authors.initials: GM
authors.lastname: Eastwood
authors.affiliation: Australian and New Zealand Intensive Care Research Centre and Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia.
authors.forename: Rinaldo
authors.initials: R
authors.lastname: Bellomo
authors.affiliation: Department of Intensive Care, Austin Hospital, Melbourne, Australia. Electronic address: Andrew.Hilton@austin.org.au.
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Hilton
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology*; D001916:Brachial Artery / Q000000981:diagnostic imaging* / Q000502:physiology*; D002302:Cardiac Output / Q000502:physiology; D002339:Carotid Arteries / Q000000981:diagnostic imaging* / Q000502:physiology*; D015150:Echocardiography, Doppler / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011182:Postoperative Care / Q000379:methods; D011446:Prospective Studies; D014656:Vascular Surgical Procedures / Q000379:methods*
keywords: arterial Doppler blood flow; cardiac index; cardiac surgery