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Andersen MJ, Wolsk E, Bakkestrøm R, Christensen N, Carter-Storch R, Omar M, Dahl JS, Frederiksen PH, Borlaug B, Gustafsson F, Hassager C, Moller JE. Pressure–flow responses to exercise in aortic stenosis, mitral regurgitation and diastolic dysfunction. Heart 2022; 108:1895-1903. [PMID: 36356959 PMCID: PMC9664118 DOI: 10.1136/heartjnl-2022-321204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 07/25/2022] [Indexed: 11/25/2022] Open
Abstract
Background Haemodynamic exercise testing is important for evaluating patients with dyspnoea on exertion and preserved ejection fraction. Despite very different pathologies, patients with pressure (aortic stenosis (AS)) and volume (mitral regurgitation (MR)) overload and diastolic dysfunction after recent acute myocardial infarction (AMI) reach similar filling pressure levels with exercise. The pressure–flow relationships (the association between change in cardiac output (∆CO) and change in pulmonary arterial wedge pressure (∆PAWP) may provide insight into haemodynamic adaptation to exercise in these groups. Methods and results One hundred sixty-eight subjects aged >50 years with a left ventricular ejection fraction of ≥50% underwent invasive exercise testing. They were enrolled in four different studies: AS (40 patients), AMI (52 patients), MR (43 patients) and 33 healthy subjects. Haemodynamic data were measured at rest, at 25 W, 75 W and at peak exercise. In all groups, PAWP increased with exercise. The greatest increase was observed in patients with AMI (from 12.7±3.9 mm Hg to 33.1±8.2 mm Hg, p<0.0001) and patients with AS (from 11.8±3.9 mm Hg to 31.4±6.1 mm Hg, p<0.0001), and the smallest was observed in healthy subjects (from 8.3±2.4 mm Hg to 21.1±7.5 mm Hg, p<0.0001). In all groups, the relative pressure increase was greatest at the beginning of the exercise. CO increased most in healthy patients (from 5.3±1.1 to 16.0±3.0 L/min, p<0.0001) and least in patients with AS (from 5.3±1.2 L/min to 12.4±2.6 L/min, p<0.0001). The pressure–flow relationships (∆PAWP/∆CO) and differed among groups (p=0.02). In all groups, the pressure–flow relationship was steepest in the initial phase of the exercise test. The AMI and AS groups (2.3±1.2 mm Hg/L/min and 3.0±1.3 mm Hg/L/min, AMI and AS, respectively) had the largest overall pressure–flow relationship; the healthy group had the smallest initially and at peak exercise (1.3±1.1 mm Hg/L/min) followed by MR group (1.9±1.4 mm Hg/L/min). Conclusion The pressure–flow relationship was steepest in the initial phase of the exercise test in all groups. The pressure–flow relationship differs between groups. Trial registration numbers NCT01974557, NCT01046838, NCT02961647 and NCT02395107.
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Affiliation(s)
- Mads J Andersen
- Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark
| | - Emil Wolsk
- Department of Cardiology, Rigshospitalet, Copenhagen, Denmark
| | - Rine Bakkestrøm
- Department of Cardiology, Odense University Hospital, Odense, Denmark
| | | | | | - Massar Omar
- Department of Cardiology, Odense University Hospital, Odense, Denmark
| | - Jordi S Dahl
- Department of Cardiology, Odense University Hospital, Odense, Denmark
| | | | - Barry Borlaug
- Department of Cardiology, Mayo Clinic Minnesota, Rochester, Minnesota, USA
| | - Finn Gustafsson
- Department of Cardiology, Rigshospitalet, Copenhagen, Denmark
| | | | - Jacob E Moller
- Department of Cardiology, Rigshospitalet, Copenhagen, Denmark
- Department of Cardiology, Odense University Hospital, Odense, Denmark
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Hardin EA, Stoller D, Lawley J, Howden EJ, Hieda M, Pawelczyk J, Jarvis S, Prisk K, Sarma S, Levine BD. Noninvasive Assessment of Cardiac Output: Accuracy and Precision of the Closed-Circuit Acetylene Rebreathing Technique for Cardiac Output Measurement. J Am Heart Assoc 2020; 9:e015794. [PMID: 32851906 PMCID: PMC7660774 DOI: 10.1161/jaha.120.015794] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Background Accurate assessment of cardiac output is critical to the diagnosis and management of various cardiac disease states; however, clinical standards of direct Fick and thermodilution are invasive. Noninvasive alternatives, such as closed‐circuit acetylene (C2H2) rebreathing, warrant validation. Methods and Results We analyzed 10 clinical studies and all available cardiopulmonary stress tests performed in our laboratory that included a rebreathing method and direct Fick or thermodilution. Studies included healthy individuals and patients with clinical disease. Simultaneous cardiac output measurements were obtained under normovolemic, hypovolemic, and hypervolemic conditions, along with submaximal and maximal exercise. A total of 3198 measurements in 519 patients were analyzed (mean age, 59 years; 48% women). The C2H2 method was more precise than thermodilution in healthy individuals with half the typical error (TE; 0.34 L/min [r=0.92] and coefficient of variation, 7.2%) versus thermodilution (TE=0.67 [r=0.70] and coefficient of variation, 13.2%). In healthy individuals during supine rest and upright exercise, C2H2 correlated well with thermodilution (supine: r=0.84, TE=1.02; exercise: r=0.82, TE=2.36). In patients with clinical disease during supine rest, C2H2 correlated with thermodilution (r=0.85, TE=1.43). C2H2 was similar to thermodilution and nitrous oxide (N2O) rebreathing technique compared with Fick in healthy adults (C2H2 rest: r=0.85, TE=0.84; C2H2 exercise: r=0.87, TE=2.39; thermodilution rest: r=0.72, TE=1.11; thermodilution exercise: r=0.73, TE=2.87; N2O rest: r=0.82, TE=0.94; N2O exercise: r=0.84, TE=2.18). The accuracy of the C2H2 and N2O methods was excellent (r=0.99, TE=0.58). Conclusions The C2H2 rebreathing method is more precise than, and as accurate as, the thermodilution method in a variety of patients, with accuracy similar to an N2O rebreathing method approved by the US Food and Drug Administration.
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Affiliation(s)
- E Ashley Hardin
- Division of Cardiology Department of Internal Medicine University of Texas Southwestern Medical Center Dallas TX.,Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas TX
| | - Douglas Stoller
- Division of Cardiology Department of Internal Medicine University of Texas Southwestern Medical Center Dallas TX.,Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas TX
| | - Justin Lawley
- Division of Cardiology Department of Internal Medicine University of Texas Southwestern Medical Center Dallas TX.,Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas TX
| | - Erin J Howden
- Division of Cardiology Department of Internal Medicine University of Texas Southwestern Medical Center Dallas TX.,Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas TX
| | - Michinari Hieda
- Division of Cardiology Department of Internal Medicine University of Texas Southwestern Medical Center Dallas TX.,Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas TX
| | - James Pawelczyk
- Department of Physiology Pennsylvania State University University Park and Hershey PA
| | - Sara Jarvis
- Department of Biological Sciences Northern Arizona University Flagstaff AZ
| | - Kim Prisk
- Department of Medicine University of California at San Diego La Jolla CA
| | - Satyam Sarma
- Division of Cardiology Department of Internal Medicine University of Texas Southwestern Medical Center Dallas TX.,Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas TX
| | - Benjamin D Levine
- Division of Cardiology Department of Internal Medicine University of Texas Southwestern Medical Center Dallas TX.,Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas TX
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Wetterslev M, Møller-Sørensen H, Johansen RR, Perner A. Systematic review of cardiac output measurements by echocardiography vs. thermodilution: the techniques are not interchangeable. Intensive Care Med 2016; 42:1223-33. [DOI: 10.1007/s00134-016-4258-y] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 02/01/2016] [Indexed: 11/29/2022]
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Kirkeby-Garstad I, Trønnes H, Stenseth R, Sellevold OFM, Aadahl P, Skogvoll E. The Precision of Pulmonary Artery Catheter Bolus Thermodilution Cardiac Output Measurements Varies With the Clinical Situation. J Cardiothorac Vasc Anesth 2014; 29:881-8. [PMID: 25976600 DOI: 10.1053/j.jvca.2014.12.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To investigate the effects of ventilatory mode, injectate temperature, and clinical situation on the precision of cardiac output measurements. DESIGN Randomized, prospective observational study. SETTING Single university hospital. PARTICIPANTS Forty patients undergoing planned cardiac surgery, receiving a pulmonary artery catheter according to institutional routine. INTERVENTIONS Cardiac output was measured at 4 predefined time points during the perioperative patient course, twice during controlled and twice during spontaneous ventilation, using 2 blocks of 8 measurement replications with cold and tepid injectate in random order. MEASUREMENTS AND MAIN RESULTS The data were analyzed using a hierarchical linear mixed model. Clinical precision was determined as half the width of the 95% confidence interval for the underlying true value. The single-measurement precision measured in 2 different clinical situations for each temperature/ventilation combination was 8% to 10%, 11% to 13%, 13% to 15%, and 23% to 24% in controlled ventilation with cold injectate, controlled ventilation with tepid injectate, spontaneous breathing with cold injectate, and spontaneous breathing with tepid injectate, respectively. Tables are provided for the number of replications needed to achieve a certain precision and for how to identify significant changes in cardiac output. CONCLUSIONS Clinical precision of cardiac output measurements is reduced significantly during spontaneous relative to controlled ventilation. The differences in precision between repeated measurement series within the temperature/ventilation combinations indicate influence of other situation-specific factors not related to ventilatory mode. Compared with tepid injectate in patients breathing spontaneously, the precision is 3-fold better with cold injectate and controlled ventilation.
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Affiliation(s)
- Idar Kirkeby-Garstad
- Department of Anesthesiology and Intensive Care, St. Olav University Hospital, Trondheim, Norway.
| | - Håkon Trønnes
- Department of Anesthesiology and Intensive Care, St. Olav University Hospital, Trondheim, Norway
| | - Roar Stenseth
- Department of Anesthesiology and Intensive Care, St. Olav University Hospital, Trondheim, Norway; Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway
| | - Olav F M Sellevold
- Department of Anesthesiology and Intensive Care, St. Olav University Hospital, Trondheim, Norway; Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway
| | - Petter Aadahl
- Department of Anesthesiology and Intensive Care, St. Olav University Hospital, Trondheim, Norway; Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway
| | - Eirik Skogvoll
- Department of Anesthesiology and Intensive Care, St. Olav University Hospital, Trondheim, Norway; Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway
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Berthelsen PG. A matter of the heart. Acta Anaesthesiol Scand 2012; 56:401-3. [PMID: 22924166 DOI: 10.1111/j.1399-6576.2011.02618.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Culwell NM, Bonagura JD, Schober KE. Comparison of echocardiographic indices of myocardial strain with invasive measurements of left ventricular systolic function in anesthetized healthy dogs. Am J Vet Res 2011; 72:650-60. [DOI: 10.2460/ajvr.72.5.650] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Determination of the precision error of the pulmonary artery thermodilution catheter using an in vitro continuous flow test rig. Anesth Analg 2010; 112:70-7. [PMID: 21127281 DOI: 10.1213/ane.0b013e3181ff475e] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Thermodilution cardiac output using a pulmonary artery catheter is the reference method against which all new methods of cardiac output measurement are judged. However, thermodilution lacks precision and has a quoted precision error of ± 20%. There is uncertainty about its true precision and this causes difficulty when validating new cardiac output technology. Our aim in this investigation was to determine the current precision error of thermodilution measurements. METHODS A test rig through which water circulated at different constant rates with ports to insert catheters into a flow chamber was assembled. Flow rate was measured by an externally placed transonic flowprobe and meter. The meter was calibrated by timed filling of a cylinder. Arrow and Edwards 7Fr thermodilution catheters, connected to a Siemens SC9000 cardiac output monitor, were tested. Thermodilution readings were made by injecting 5 mL of ice-cold water. Precision error was divided into random and systematic components, which were determined separately. Between-readings (random) variability was determined for each catheter by taking sets of 10 readings at different flow rates. Coefficient of variation (CV) was calculated for each set and averaged. Between-catheter systems (systematic) variability was derived by plotting calibration lines for sets of catheters. Slopes were used to estimate the systematic component. Performances of 3 cardiac output monitors were compared: Siemens SC9000, Siemens Sirecust 1261, and Philips MP50. RESULTS Five Arrow and 5 Edwards catheters were tested using the Siemens SC9000 monitor. Flow rates between 0.7 and 7.0 L/min were studied. The CV (random error) for Arrow was 5.4% and for Edwards was 4.8%. The random precision error was ± 10.0% (95% confidence limits). CV (systematic error) was 5.8% and 6.0%, respectively. The systematic precision error was ± 11.6%. The total precision error of a single thermodilution reading was ± 15.3% and ± 13.0% for triplicate readings. Precision error increased by 45% when using the Sirecust monitor and 100% when using the Philips monitor. CONCLUSION In vitro testing of pulmonary artery catheters enabled us to measure both the random and systematic error components of thermodilution cardiac output measurement, and thus calculate the precision error. Using the Siemens monitor, we established a precision error of ± 15.3% for single and ± 13.0% for triplicate reading, which was similar to the previous estimate of ± 20%. However, this precision error was significantly worsened by using the Sirecust and Philips monitors. Clinicians should recognize that the precision error of thermodilution cardiac output is dependent on the selection of catheter and monitor model.
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Walsh E, Adams S, Chernipeski J, Cloud J, Gillies E, Fox R, Luckeroth P, Rice M, Salamanca C, Sherman B, Nezworski A, Ash T. Iced vs room-temperature injectates for cardiac index measurement during hypothermia and normothermia. Am J Crit Care 2010; 19:365-72. [PMID: 19687516 DOI: 10.4037/ajcc2009255] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
BACKGROUND Few data are available on the accuracy of thermodilution measurements of cardiac index with room-temperature injectates and a closed delivery system in patients with low cardiac indexes and/or hypothermic body temperatures. OBJECTIVE To compare iced and room-temperature injectates for thermodilution measurement of cardiac index in postoperative cardiac surgical patients during hypothermia and normothermia. METHODS In a convenience sample of cardiac surgical patients in a cardiac recovery unit, cardiac index was measured with both room-temperature and iced injectates during hypothermia (< or =36.0 degrees C) and normothermia (> or =36.1 degrees C and < or =38.0 degrees C). Device bias and precision were calculated and graphed by using the Bland-Altman method. A Student t test was used to determine differences between cardiac indexes by injectate temperature. RESULTS A total of 38 patients were studied. Mean bias and precision for room-temperature and iced injectates in all patients were 0.11 (SD, 0.27) during hypothermia and -0.03 (SD, 0.21) during normothermia. In hypothermic patients, cardiac index differed significantly between room-temperature and iced injectates (t(1,37) = 2.41, P = .02). Cardiac index measurements did not differ between room-temperature and iced injectates in normothermic patients (P = .33). CONCLUSIONS Although significant differences in thermodilution cardiac index were found between room-temperature and iced injectates during hypothermic body temperatures, these differences were small (mean, <0.11). These findings add to the results of the few studies on accuracy of room-temperature injectates for thermodilution measurement of cardiac index.
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Affiliation(s)
- Elissa Walsh
- Elissa Walsh, Sheila Adams, Janine Chernipeski, Jenny Cloud, Elizabeth Gillies, Robert Fox, Patti Luckeroth, Marsha Rice, Cora Salamanca, Betty Sherman, and Andrea Nezworski are staff nurses in the cardiac recovery unit and Tracey Ash is a cardiovascular clinical nurse specialist at Providence St Vincent’s Medical Center in Portland, Oregon
| | - Sheila Adams
- Elissa Walsh, Sheila Adams, Janine Chernipeski, Jenny Cloud, Elizabeth Gillies, Robert Fox, Patti Luckeroth, Marsha Rice, Cora Salamanca, Betty Sherman, and Andrea Nezworski are staff nurses in the cardiac recovery unit and Tracey Ash is a cardiovascular clinical nurse specialist at Providence St Vincent’s Medical Center in Portland, Oregon
| | - Janine Chernipeski
- Elissa Walsh, Sheila Adams, Janine Chernipeski, Jenny Cloud, Elizabeth Gillies, Robert Fox, Patti Luckeroth, Marsha Rice, Cora Salamanca, Betty Sherman, and Andrea Nezworski are staff nurses in the cardiac recovery unit and Tracey Ash is a cardiovascular clinical nurse specialist at Providence St Vincent’s Medical Center in Portland, Oregon
| | - Jenny Cloud
- Elissa Walsh, Sheila Adams, Janine Chernipeski, Jenny Cloud, Elizabeth Gillies, Robert Fox, Patti Luckeroth, Marsha Rice, Cora Salamanca, Betty Sherman, and Andrea Nezworski are staff nurses in the cardiac recovery unit and Tracey Ash is a cardiovascular clinical nurse specialist at Providence St Vincent’s Medical Center in Portland, Oregon
| | - Elizabeth Gillies
- Elissa Walsh, Sheila Adams, Janine Chernipeski, Jenny Cloud, Elizabeth Gillies, Robert Fox, Patti Luckeroth, Marsha Rice, Cora Salamanca, Betty Sherman, and Andrea Nezworski are staff nurses in the cardiac recovery unit and Tracey Ash is a cardiovascular clinical nurse specialist at Providence St Vincent’s Medical Center in Portland, Oregon
| | - Robert Fox
- Elissa Walsh, Sheila Adams, Janine Chernipeski, Jenny Cloud, Elizabeth Gillies, Robert Fox, Patti Luckeroth, Marsha Rice, Cora Salamanca, Betty Sherman, and Andrea Nezworski are staff nurses in the cardiac recovery unit and Tracey Ash is a cardiovascular clinical nurse specialist at Providence St Vincent’s Medical Center in Portland, Oregon
| | - Patti Luckeroth
- Elissa Walsh, Sheila Adams, Janine Chernipeski, Jenny Cloud, Elizabeth Gillies, Robert Fox, Patti Luckeroth, Marsha Rice, Cora Salamanca, Betty Sherman, and Andrea Nezworski are staff nurses in the cardiac recovery unit and Tracey Ash is a cardiovascular clinical nurse specialist at Providence St Vincent’s Medical Center in Portland, Oregon
| | - Marsha Rice
- Elissa Walsh, Sheila Adams, Janine Chernipeski, Jenny Cloud, Elizabeth Gillies, Robert Fox, Patti Luckeroth, Marsha Rice, Cora Salamanca, Betty Sherman, and Andrea Nezworski are staff nurses in the cardiac recovery unit and Tracey Ash is a cardiovascular clinical nurse specialist at Providence St Vincent’s Medical Center in Portland, Oregon
| | - Cora Salamanca
- Elissa Walsh, Sheila Adams, Janine Chernipeski, Jenny Cloud, Elizabeth Gillies, Robert Fox, Patti Luckeroth, Marsha Rice, Cora Salamanca, Betty Sherman, and Andrea Nezworski are staff nurses in the cardiac recovery unit and Tracey Ash is a cardiovascular clinical nurse specialist at Providence St Vincent’s Medical Center in Portland, Oregon
| | - Betty Sherman
- Elissa Walsh, Sheila Adams, Janine Chernipeski, Jenny Cloud, Elizabeth Gillies, Robert Fox, Patti Luckeroth, Marsha Rice, Cora Salamanca, Betty Sherman, and Andrea Nezworski are staff nurses in the cardiac recovery unit and Tracey Ash is a cardiovascular clinical nurse specialist at Providence St Vincent’s Medical Center in Portland, Oregon
| | - Andrea Nezworski
- Elissa Walsh, Sheila Adams, Janine Chernipeski, Jenny Cloud, Elizabeth Gillies, Robert Fox, Patti Luckeroth, Marsha Rice, Cora Salamanca, Betty Sherman, and Andrea Nezworski are staff nurses in the cardiac recovery unit and Tracey Ash is a cardiovascular clinical nurse specialist at Providence St Vincent’s Medical Center in Portland, Oregon
| | - Tracey Ash
- Elissa Walsh, Sheila Adams, Janine Chernipeski, Jenny Cloud, Elizabeth Gillies, Robert Fox, Patti Luckeroth, Marsha Rice, Cora Salamanca, Betty Sherman, and Andrea Nezworski are staff nurses in the cardiac recovery unit and Tracey Ash is a cardiovascular clinical nurse specialist at Providence St Vincent’s Medical Center in Portland, Oregon
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Østergaard M, Nielsen J, Nygaard E. Pulse contour cardiac output: an evaluation of the FloTrac method. Eur J Anaesthesiol 2009; 26:484-9. [DOI: 10.1097/eja.0b013e32831f343f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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10
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Lithium dilution cardiac output measurement in the critically ill patient: determination of precision of the technique. Intensive Care Med 2008; 35:498-504. [DOI: 10.1007/s00134-008-1292-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2007] [Accepted: 08/10/2008] [Indexed: 10/21/2022]
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Ostergaard M, Nilsson LB, Nilsson JC, Rasmussen JP, Berthelsen PG. Precision of bolus thermodilution cardiac output measurements in patients with atrial fibrillation. Acta Anaesthesiol Scand 2005; 49:366-72. [PMID: 15752403 DOI: 10.1111/j.1399-6576.2005.00613.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND The precision of bolus thermodilution cardiac output measurements in patients with atrial fibrillation (AF) has not previously been determined. A priori we suspected that the precision would be lower in patients with AF than in patients with sinus rhythm (SR). Consequently, we also determined if the precision could be improved by injecting the thermal indicator into the right ventricle instead of the right atrium. METHODS Cardiac output was determined as the average result of four injections of 10 ml of iced saline. Replicate measurements were performed with thermal indicator injections into the right atrium and ventricle. The coefficients of variation and the precisions were calculated. RESULTS In the 25 patients with AF, mean cardiac output was 3.96 l min(-1) (range 2.4-7.4), the coefficient of variation 0.073 (95% CI +/- 0.011), and the precision 0.38 l min(-1) (95% CI +/- 0.14) with injection into the right atrium. In the 25 patients with SR, mean cardiac output was 4.73 l min(-1) (range 2.4-7.3), the coefficient of variation 0.047(95% CI +/- 0.006), and the precision 0.38 l min(-1) (95% CI +/- 0.14). In both groups, an agreement analysis demonstrated that the injection of indicator into the right ventricle resulted in a significantly higher cardiac output [AF+0.25 (95% CI +/- 0.15) l min(-1), SR+0.29 ( +/- 0.20) l min(-1)]. CONCLUSION The coefficient of variation for cardiac output determinations is 55% higher in patients with AF. Two measurements, separated by time or intervention, must differ by 15% in AF patients and 9% in SR patients before one can be 95% confident that a real change has taken place.
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Affiliation(s)
- M Ostergaard
- Department of Anesthesiology, Gentofte Hospital, University of Copenhagen, Denmark
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Nilsson LB, Nilsson JC, Skovgaard LT, Berthelsen PG. Thermodilution cardiac output--are three injections enough? Acta Anaesthesiol Scand 2004; 48:1322-7. [PMID: 15504196 DOI: 10.1111/j.1399-6576.2004.00514.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND Bolus thermodilution cardiac output measurements have been a mainstay in clinical monitoring of critically ill patients for more than 30 years. Usually the results of an arbitrarily chosen number (1-6) of thermal indicator injections are averaged to increase the reliability of the measurement. The number of injections needed to achieve a given level of precision has, however, not previously been systematically investigated. METHODS AND RESULTS In 80 hemodynamically stable patients cardiac output was determined as the average of eight injections of 10 ml of iced saline. From the 638 measurements we examined the relationship between the number of thermal indicator injections and the precision of the resulting cardiac output estimate. Furthermore, the association between the number of injections and the least detectable difference among two sets of measurements was established. CONCLUSION The current study shows that one needs to average the results of four injections to be 95% confident that the result is within 5% of the 'true' cardiac output and that two series of four measurements have to differ by at least 7% before one can be sure (95%) that a change in cardiac function has taken place.
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Affiliation(s)
- L B Nilsson
- Department of Anesthesiology, Gentofte Hospital, Denmark
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