Reliability of a new algorithm for continuous cardiac output determination by pulse-contour analysis during hemodynamic instability

Objective The method of determining continuous cardiac output (CO) with beat-to-beat pulse-contour analysis calibrated by transthoracic thermodilution is gaining much wider clinical acceptance. However, some questions have been raised regarding the reliability of this method during periods of profound hemodynamic instability. We validated the original calculation of pulse-contour analysis and a new, improved algorithm against thermodilution-derived measurements of CO in patients with changes of CO >20%. Design Comparative study. Setting Cardiac surgical intensive care unit of a university hospital. Patients Twenty-four patients after cardiac surgery who experienced changes of CO >±20% during their postoperative course. Interventions CO was measured by transthoracic thermodilution and pulse-contour analysis (PiCCO, PULSION Medical Systems, Munich, Germany) at serial intervals every 60 mins during study periods of 8–44 hrs. During this time, no recalibration of the pulse-contour computer was performed. Measurements and Main Results A total of 517 simultaneous measurements of thermodilution CO and pulse-contour CO measured by the two different algorithms were compared by regression, structural regression, and Bland-Altman analyses. Mean change of CO was 40% ± 27% (range, 20% to 139%), range of systemic vascular resistance was 450–2360 dyne·sec/cm5. Correlation of the original pulse-contour algorithm to thermodilution CO was r = .76, with p = .027; bias was 0.08 L/min, with 1.8 L/min single sd. Correlation of the improved pulse-contour algorithm to thermodilution CO was r = .88, with p = .0001; bias was 0.2 L/min, with 1.2 L/min single sd. Mean CO by the new pulse-contour algorithm did not differ significantly from CO by thermodilution during the study period. The difference between the methods was not influenced by variations of heart rate or arterial pressure. Conclusions CO measurement by arterial pulse-contour analysis based on a new, improved algorithm is reliable, even in patients with profound changes of CO and during periods of hemodynamic instability.

[1]  B. Reichart,et al.  Reproducibility of double indicator dilution measurements of intrathoracic blood volume compartments, extravascular lung water, and liver function. , 1998, Chest.

[2]  B. Brown,et al.  Evaluation of the Pulse‐Contour Method of Determining Stroke Volume in Man , 1972, Circulation.

[3]  A. Weyland,et al.  Comparison of cardiac output assessed by pulse-contour analysis and thermodilution in patients undergoing minimally invasive direct coronary artery bypass grafting. , 1999, Journal of cardiothoracic and vascular anesthesia.

[4]  J. Vincent,et al.  Yearbook of Intensive Care and Emergency Medicine , 1995, Yearbook of Intensive Care and Emergency Medicine.

[5]  H. Reichenspurner,et al.  Less invasive, continuous hemodynamic monitoring during minimally invasive coronary surgery. , 1999, The Annals of thoracic surgery.

[6]  L. Golding,et al.  Comparison of brachial and radial arterial pressure monitoring in patients undergoing coronary artery bypass surgery. , 1990, Anesthesiology.

[7]  A. Hoeft,et al.  HZV-Bestimmung mittels transpulmonaler Thermodilution Eine Alternative zum Pulmonaliskatheter? , 1996, Der Anaesthesist.

[8]  M. Haller,et al.  Beat-to-beat measurement of cardiac output by intravascular pulse contour analysis: a prospective criterion standard study in patients after cardiac surgery. , 2000, Journal of cardiothoracic and vascular anesthesia.

[9]  H. Forst,et al.  Die kontinuierliche Messung des Herzzeitvolumens mit der Pulskonturanalyse , 1995, Der Anaesthesist.

[10]  R. Bone,et al.  Is it time to pull the pulmonary artery catheter? , 1996, JAMA.

[11]  B. Reichart,et al.  Hemodynamic monitoring by double-indicator dilution technique in patients after orthotopic heart transplantation. , 2000 .

[12]  H. Swan,et al.  A new technique for measurement of cardiac output by thermodilution in man. , 1972, The American journal of cardiology.

[13]  K. Wesseling,et al.  Continuous cardiac output in septic shock by simulating a model of the aortic input impedance: a comparison with bolus injection thermodilution. , 1999, Anesthesiology.

[14]  B. Reichart,et al.  Continuous cardiac output by femoral arterial thermodilution calibrated pulse contour analysis: comparison with pulmonary arterial thermodilution. , 1999, Critical care medicine.

[15]  A. Liebold,et al.  Continuous cardiac output measurement: pulse contour analysis vs thermodilution technique in cardiac surgical patients. , 1999, British journal of anaesthesia.

[16]  N. T. Smith,et al.  A simple device for the continuous measurement of cardiac output. Its model basis and experimental verification , 1983 .

[17]  C. Weissman,et al.  Pulse contour cardiac output in surgical intensive care unit patients. , 1993, Journal of clinical anesthesia.

[18]  F. Lewis,et al.  Cardiac output measurement using femoral artery thermodilution in patients , 1989 .

[19]  Evaluation of Cardiac Output and Cardiac Preload , 2000 .

[20]  K. Reinhart,et al.  Comparison of pulmonary artery and arterial thermodilution cardiac output in critically ill patients , 1999, Intensive Care Medicine.

[21]  T. Dorman,et al.  Radial artery pressure monitoring underestimates central arterial pressure during vasopressor therapy in critically ill surgical patients. , 1998, Critical care medicine.

[22]  S. Tibby,et al.  Clinical validation of cardiac output measurements using femoral artery thermodilution with direct Fick in ventilated children and infants , 1997, Intensive Care Medicine.

[23]  K. Reinhart,et al.  Is the placement of a pulmonary artery catheter still justified solely for the measurement of cardiac output? , 2000, Journal of cardiothoracic and vascular anesthesia.

[24]  G. Diamond,et al.  Catheterization of the heart in man with use of a flow-directed balloon-tipped catheter. , 1970, The New England journal of medicine.

[25]  Karel H. Wesseling,et al.  Continuous cardiac output monitoring by pulse contour during cardiac surgery , 1990 .

[26]  O Gödje,et al.  Central venous pressure, pulmonary capillary wedge pressure and intrathoracic blood volumes as preload indicators in cardiac surgery patients. , 1998, European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery.

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

[28]  N. T. Smith,et al.  Beat to Beat Cardiac Output from the Arterial Pressure Pulse Contour , 1974 .

[29]  J R Jansen,et al.  Computation of aortic flow from pressure in humans using a nonlinear, three-element model. , 1993, Journal of applied physiology.

[30]  William A. Knaus,et al.  The effectiveness of right heart catheterization in the initial care of critically ill patients. SUPPORT Investigators. , 1996, Journal of the American Medical Association (JAMA).

[31]  L. Goldman,et al.  The effectiveness of right heart catheterization in the initial care of critically ill patients. SUPPORT Investigators. , 1996, JAMA.

[32]  A. Mcluckie,et al.  A comparison of pulmonary and femoral artery thermodilution cardiac indices in paediatric intensive care patients , 1996, Acta paediatrica.