Pulmonary blood volume measured by contrast enhanced ultrasound: a comparison with transpulmonary thermodilution.

BACKGROUND Blood volume quantification is essential for haemodynamic evaluation guiding fluid management in anaesthesia and intensive care practice. Ultrasound contrast agent (UCA)-dilution measured by contrast enhanced ultrasound (CEUS) can provide the UCA mean transit time (MTT) between the right and left heart, enabling the assessment of the intrathoracic blood volume (ITBV(UCA)). The purpose of the present study was to investigate the agreement between UCA-dilution using CEUS and transpulmonary thermodilution (TPTD) in vitro and in vivo. METHODS In an in vitro setup, with variable flows and volumes, we injected a double indicator, ice-cold saline with SonoVue(®), and performed volume measurements using transesophageal echo and thermodilution by PiCCO(®). In a pilot study, we assigned 17 patients undergoing elective cardiac surgery for pulmonary blood volume (PBV) measurement using TPTD by PiCCO(®) and ITBV by UCA-dilution. Correlation coefficients and Bland-Altman analysis were performed for all volume measurements. RESULTS In vitro, 73 experimental MTT's were obtained using PiCCO(®) and UCA-dilution. The volumes by PiCCO(®) and UCA-dilution correlated with true volumes; r(s)=0.96 (95% CI, 0.93-0.97; P<0.0001) and r(s)=0.97 (95% CI, 0.95-0.98; P<0.0001), respectively. The bias of PBV by PiCCO(®) and ITBV(UCA) were -380 ml and -42 ml, respectively. In 16 patients, 86 measurements were performed. The correlation between PBV by PiCCO(®) and ITBV(UCA) was r(s)=0.69 (95% CI 0.55-0.79; P<0.0001). Bland-Altman analysis revealed a bias of -323 ml. CONCLUSIONS ITBV assessment with CEUS seems a promising technique for blood volume measurement, which is minimally-invasive and bedside applicable. CLINICAL TRIAL REGISTRATION ISRCTN90330260.

[1]  M. Merrell,et al.  The Dye Dilution Method for Describing the Central Circulation: An Analysis of Factors Shaping the Time‐Concentration Curves , 1951, Circulation.

[2]  F. Grodins,et al.  Basic Concepts in the Determination of vascular Volumes by Indicator‐Dilution Methods , 1962, Circulation research.

[3]  A. Goetz,et al.  Intrathoracic blood volume index measured by thermodilution for preload monitoring after cardiac surgery. , 2002, Journal of cardiothoracic and vascular anesthesia.

[4]  A. V. van Zundert,et al.  Acute Hemodynamic Effects of Cardiac Resynchronization Therapy in Patients with Poor Left Ventricular Function During Cardiac Surgery , 2009, Journal of cardiac surgery.

[5]  R. Jones,et al.  Quantitative radionuclide angiocardiography for determination of chamber to chamber cardiac transit times. , 1972, The American journal of cardiology.

[6]  P. Neumann,et al.  Extravascular lung water and intrathoracic blood volume: double versus single indicator dilution technique , 1999, Intensive Care Medicine.

[7]  J. Finn,et al.  Heart failure: evaluation of cardiopulmonary transit times with time-resolved MR angiography. , 2003, Radiology.

[8]  R. Schmid,et al.  Volume assessment in patients with necrotizing pancreatitis: A comparison of intrathoracic blood volume index, central venous pressure, and hematocrit, and their correlation to cardiac index and extravascular lung water index* , 2008, Critical care medicine.

[9]  M. Mischi,et al.  Identification of cardiovascular dilution systems by contrast ultrasound. , 2007, Ultrasound in medicine & biology.

[10]  A. Beckett,et al.  AKUFO AND IBARAPA. , 1965, Lancet.

[11]  Paolo Pietropaoli,et al.  Preload index: pulmonary artery occlusion pressure versus intrathoracic blood volume monitoring during lung transplantation. , 2002 .

[12]  D. Altman,et al.  Agreement Between Methods of Measurement with Multiple Observations Per Individual , 2007, Journal of biopharmaceutical statistics.

[13]  R. Beale,et al.  Assessment of cardiac preload and extravascular lung water by single transpulmonary thermodilution , 2000, Intensive Care Medicine.

[14]  N. Reichek,et al.  Left Ventricular Filling Pressure Assessment Using Left Atrial Transit Time by Cardiac Magnetic Resonance Imaging , 2011, Circulation. Cardiovascular imaging.

[15]  Jan de Koning,et al.  Relationships between volume and pressure measurements and stroke volume in critically ill patients , 2000, Critical care.

[16]  M. Wise,et al.  Tracer dilution curves in cardiology and random walk and lognormal distributions. , 1966, Acta physiologica et pharmacologica Neerlandica.

[17]  W. Milnor,et al.  The Pulmonary Blood Volume in Rheumatic Heart Disease and Its Alteration by Isoproterenol , 1963, Circulation.

[18]  Ingeborg H. F. Herold,et al.  Volume quantification by contrast-enhanced ultrasound: an in-vitro comparison with true volumes and thermodilution , 2013, Cardiovascular Ultrasound.

[19]  B. Reichart,et al.  Intensive care unit procedures: cost savings and patient safety , 2000, Critical Care.

[20]  D. Schuster,et al.  Extravascular lung water measurements and hemodynamic monitoring in the critically ill: bedside alternatives to the pulmonary artery catheter. , 2006, American journal of physiology. Lung cellular and molecular physiology.

[22]  D. Altman,et al.  STATISTICAL METHODS FOR ASSESSING AGREEMENT BETWEEN TWO METHODS OF CLINICAL MEASUREMENT , 1986, The Lancet.

[23]  P. Fabbro-Péray,et al.  The Intrathoracic Blood Volume Index as an Indicator of Fluid Responsiveness in Critically Ill Patients with Acute Circulatory Failure: A Comparison with Central Venous Pressure , 2008, Anesthesia and analgesia.

[24]  Wise Me,et al.  Tracer dilution curves in cardiology and random walk and lognormal distributions. , 1966 .

[25]  E. Korsten,et al.  Contrast echocardiography for pulmonary blood volume quantification , 2004, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[26]  K. Reinhart,et al.  Comparison between intrathoracic blood volume and cardiac filling pressures in the early phase of hemodynamic instability of patients with sepsis or septic shock. , 1999, Journal of critical care.

[27]  G. Galstyan,et al.  Comparison of cardiac output and blood volumes in intrathoracic compartments measured by ultrasound dilution and transpulmonary thermodilution methods , 2010, Intensive Care Medicine.

[28]  S. Roy,et al.  Pulmonary blood volume in mitral stenosis. , 1965, British medical journal.