title: Feasibility of common carotid artery point of care ultrasound in cardiac output measurements compared to invasive methods.
abstract: BACKGROUND
  Cardiac output (CO) measurement in the intensive care unit (ICU) requires invasive devices such as the pulmonary artery (PA) catheter or arterial waveform pulse contour analysis (PCA). This study tests the accuracy and feasibility of point of care ultrasound (POCUS) of the common carotid artery to estimate the CO non-invasively and compare it to existing invasive CO measurement modalities.
  
  
  METHODS
  Patients admitted to the surgical and cardiothoracic ICU in a tertiary university-affiliated academic center during a 4-month period, with invasive hemodynamic monitoring devices for management, were included in this cohort study. Common carotid artery POCUS was performed to measure the CO and the results were compared to an invasive device.
  
  
  RESULTS
  Intensivists and ICU fellows, using ultrasound of the common carotid artery, obtained the CO measurements. Images of the Doppler flow and volume were obtained at the level of the thyroid gland. Concurrent CO measured via invasive devices was recorded. The patient cohort comprised 36 patients; 52 % were females. The average age was 59 ± 13 years, and 66 % were monitored via PCA device and 33 % via PA catheter. Intraclass correlation coefficient (ICC) analysis demonstrated almost perfect correlation (0.8152) between measurements of CO via ultrasound vs. invasive modalities. The ICC between POCUS and the invasive measurement via PCA was 0.84 and via PA catheter 0.74, showing substantial agreement between the ultrasound and both invasive modalities.
  
  
  CONCLUSIONS
  Common carotid artery POCUS offers a non-invasive method of measuring the CO in the critically ill population.
authors.affiliation: Division of Trauma and Critical Care/Department of Surgery/Senior Staff, Henry Ford Hospital, 2799 W. Grand Blvd, Detroit, Michigan, MI 48202 USA.
authors.forename: Marika
authors.initials: M
authors.lastname: Gassner
authors.affiliation: Division of Trauma and Critical Care/Department of Surgery/Senior Staff, Henry Ford Hospital, 2799 W. Grand Blvd, Detroit, Michigan, MI 48202 USA.
authors.forename: Keith
authors.initials: K
authors.lastname: Killu
authors.affiliation: Division of Trauma and Critical Care/Department of Surgery/Senior Staff, Henry Ford Hospital, 2799 W. Grand Blvd, Detroit, Michigan, MI 48202 USA.
authors.forename: Zachary
authors.initials: Z
authors.lastname: Bauman
authors.affiliation: Division of Trauma and Critical Care/Department of Surgery/Senior Staff, Henry Ford Hospital, 2799 W. Grand Blvd, Detroit, Michigan, MI 48202 USA.
authors.forename: Victor
authors.initials: V
authors.lastname: Coba
authors.affiliation: Division of Trauma and Critical Care/Department of Surgery/Senior Staff, Henry Ford Hospital, 2799 W. Grand Blvd, Detroit, Michigan, MI 48202 USA.
authors.forename: Kelly
authors.initials: K
authors.lastname: Rosso
authors.affiliation: Division of Trauma and Critical Care/Department of Surgery/Senior Staff, Henry Ford Hospital, 2799 W. Grand Blvd, Detroit, Michigan, MI 48202 USA.
authors.forename: Dionne
authors.initials: D
authors.lastname: Blyden
keywords: Cardiac output; Carotid doppler; Point of care ultrasound; Pulmonary artery catheter; Pulse contour analysis; Ultrasound