Intermittent Thermodilution Cardiac Output Research Articles

Agreement of Bioreactance Cardiac Output Monitoring With Thermodilution During Hemorrhagic Shock and Resuscitation in Adult Swine.

The study tests the hypothesis that noninvasive cardiac output monitoring based upon bioreactance (Cheetah Medical, Portland, OR) has acceptable agreement with intermittent bolus thermodilution over a wide range of cardiac output in an adult porcine model of hemorrhagic shock and resuscitation. Prospective laboratory animal investigation. Preclinical university laboratory. Eight ~ 50 kg Yorkshire swine with a femoral artery catheter for blood pressure measurement and a pulmonary artery catheter for bolus thermodilution. With the pigs anesthetized and mechanically ventilated, 40 mL/kg of blood was removed yielding marked hypotension and a rise in plasma lactate. After 60 minutes, pigs were resuscitated with shed blood and crystalloid. Noninvasive cardiac output monitoring and intermittent thermodilution cardiac output were simultaneously measured at nine time points spanning baseline, hemorrhage, and resuscitation. Simultaneous noninvasive cardiac output monitoring and thermodilution measurements of cardiac output were compared by Bland-Altman analysis. A plot was constructed using the difference of each paired measurement expressed as a percentage of the mean of the pair plotted against the mean of the pair. Percent bias was used to scale the differences in the measurements for the magnitude of the cardiac output. Method concordance was assessed from a four-quadrant plot with a 15% zone of exclusion. Overall, noninvasive cardiac output monitoring percent bias was 1.47% (95% CI, -2.5 to 5.4) with limits of agreement of upper equal to 33.4% (95% CI, 26.5-40.2) and lower equal to -30.4% (95% CI, -37.3 to -23.6). Trending analysis demonstrated a 97% concordance between noninvasive cardiac output monitoring and thermodilution cardiac output. Over the wide range of cardiac output produced by hemorrhage and resuscitation in large pigs, noninvasive cardiac output monitoring has acceptable agreement with thermodilution cardiac output.

Accuracy of Noninvasive Estimated Continuous Cardiac Output (esCCO) Compared to Thermodilution Cardiac Output: A Pilot Study in Cardiac Patients

To compare the noninvasive estimated continuous cardiac output (esCCO), device-derived cardiac output (CO) to simultaneous pulmonary artery catheter (PAC) thermodilution (TD) CO. A prospective study comparing pulse wave transit time (estimated continuous cardiac output, esCCO; Nihon Kohden, Tokyo, Japan) to intermittent TD CO. One academic hospital. Patients presenting for cardiac surgery. Intraoperative CO measurements at 4 distinct time points (after induction, after sternotomy, after cardiopulmonary bypass, and after chest closure). The study population consisted of American Society of Anesthesiologists (ASA) IV subjects, 27 (77%) males and 8 (23%) females, with a mean age of 64.6 ± 12.2 years. Data points from esCCO and TD were collected simultaneously and means per time point compared using Bland-Altman, Pearson R coefficient, and percent error. Mean TD CO for the study was 5.4 L/min. The Pearson R coefficient, percent error, and bias in L/min were: 0.57, 44%, 0.66 (after induction); 0.54, 51%, 0.88 (after sternotomy); 0.60, 60%, 0.95 (after cardiopulmonary bypass); and 0.57, 60%, 0.75 (after chest closure) respectively. esCCO is easy to use and provides continuous CO measurements, but has wide limits of agreement and large percentage errors with a consistently positive bias in comparison to TD.

Accuracy of arterial pressure waveform analysis for cardiac output measurement in comparison with thermodilution methods in patients undergoing living donor liver transplantation

The aim of this study was to assess the accuracy of the first and third versions of arterial pressure waveform cardiac output (APCO(v.1.0) and APCO(v.3.0)) measurements in comparison with thermodilution methods in patients undergoing living donor liver transplantation. Twenty patients were anesthetized and mechanically ventilated. A radial arterial line was connected to a dedicated transducer for the APCO evaluation (FloTrac™). A pulmonary artery catheter was placed and connected to a computer system (Vigilance™) to measure intermittent thermodilution cardiac output (CO(TD)) and continuous cardiac output (CCO). A total of 138 measurements were analyzed. Bland-Altman analysis showed that the mean biases for CO(TD)-APCO(v.3.0), CO(TD)-APCO(v.1.0), and CO(TD)-CCO were 0.89, 1.73, and -0.79L/min, and the adjusted percentage errors were 37.5, 30.3, and 43%, respectively. While the variance for CO(TD)-APCO(v3.0) was greater, the accuracy (bias) improved by 0.8L/min as compared with CO(TD)-APCO(v1.0). The difference CO(TD)-APCO(v.3.0) became apparent when systemic vascular resistance was lower than 1000dyne×s/cm(5), especially below 700dyne×s/cm(5). These data suggest that the accuracy of APCO(v.3.0) has improved compared to APCO(v.1.0) due to the updated algorithm, but additional improvements should be evaluated, especially in patients undergoing living donor liver transplantation with low systemic vascular resistance.

Cardiac Output Derived from Arterial Pressure Waveform Analysis in Patients Undergoing Cardiac Surgery: Validity of a Second Generation Device: Retracted

The performance of a recently introduced, arterial waveform-based device for measuring cardiac output (CO) without the need of invasive calibration (FloTrac/Vigileo) has been controversial. We designed the present study to assess the validity of an improved version of this monitoring technique compared with intermittent thermodilution CO measurement using a pulmonary artery catheter in patients undergoing cardiac surgery. Forty ASA III patients scheduled for elective coronary artery bypass grafting with cardiopulmonary bypass (CPB) were studied. Simultaneous CO measurements by bolus thermodilution and the FloTrac/Vigileo device were obtained after induction of anesthesia (T1), before CPB (T2), after CPB (T3), after sternal closure (T4), on arrival in the intensive care unit (T5), 4 h (T6), 8 h (T7), and 24 h after surgery (T8). CO was indexed to the body surface area (cardiac index, CI). A percentage error of 30% or less was established as the criterion for method interchangeability. Two hundred and eighty-two data pairs were analyzed. Thermodilution CI ranged from 1.2 to 4.1 L x min(-1) x m(-2) (mean 2.5 +/- 0.54 L x min(-1) x m(-2)). Bias and precision (1.96 sd of the bias) were 0.19 L x min(-1) x m(-2) and +/- 0.60 L x min(-1) x m(-2), resulting in an overall percentage error of 24.6%. Subgroup analysis revealed a percentage error of 28.3% for data pairs obtained intraoperatively (T1-4) and 20.7% in intensive care unit (T5-8). CI values obtained by the improved, second generation semiinvasive arterial waveform device showed good intraoperative and postoperative agreement with intermittent pulmonary artery thermodilution CI measurements in patients undergoing coronary artery bypass graft surgery.

Validation of a continuous, arterial pressure-based cardiac output measurement: a multicenter, prospective clinical trial

IntroductionThe present study compared measurements of cardiac output by an arterial pressure-based cardiac output (APCO) analysis method with measurement by intermittent thermodilution cardiac output (ICO) via pulmonary artery catheter in a clinical setting.MethodsThe multicenter, prospective clinical investigation enrolled patients with a clinical indication for cardiac output monitoring requiring pulmonary artery and radial artery catheters at two hospitals in the United States, one hospital in France, and one hospital in Belgium. In 84 patients (69 surgical patients), the cardiac output was measured by analysis of the arterial pulse using APCO and was measured via pulmonary artery catheter by ICO; to establish a reference comparison, the cardiac output was measured by continuous cardiac output (CCO). Data were collected continuously by the APCO and CCO technologies, and at least every 4 hours by ICO. No clinical interventions were made as part of the study.ResultsFor APCO compared with ICO, the bias was 0.20 l/min, the precision was ± 1.28 l/min, and the limits of agreement were -2.36 l/m to 2.75 l/m. For CCO compared with ICO, the bias was 0.66 l/min, the precision was ± 1.05 l/min, and the limits of agreement were -1.43 l/m to 2.76 l/m. The ability of APCO and CCO to assess changes in cardiac output was compared with that of ICO. In 96% of comparisons, APCO tracked the change in cardiac output in the same direction as ICO. The magnitude of change was comparable 59% of the time. For CCO, 95% of comparisons were in the same direction, with 58% of those changes being of similar magnitude.ConclusionIn critically ill patients in the intensive care unit, continuous measurement of cardiac output using either APCO or CCO is comparable with ICO. Further study in more homogeneous populations may refine specific situations where APCO reliability is strongest.

A Comparison of Cardiac Output Measurements between Non-Invasive Partial Rebreathing Method and Invasive Intermittent Thermodilution Method during Coronary Artery Bypass Graft

Background: A reliable non-invasive cardiac output measurement could enhance patient safety and reduce risk. Partial rebreathing cardiac output (RBCO) measurement is a non-invasive method based on a differential form of the CO₂ Fick equation. The relative change in CO₂ and ETCO in response to addition of dead space to the breathing circuit is used to measure cardiac output, The aim of this study was to compare this method in coronary artery bypass graft (CABG) patients during pre-cardiopulmonary bypass (CPB) and post-CPB with the currently accepted technique of intermittent thermodilution cardiac output (TDCO) measurement. Methods: Eleven patients (n = 11, age 5O ± 13 years) undergoing CABG operations with CPB were studied. We measured the cardiac output non-invasively by using a RBCO monitor (NICO, Novametrix Medical Systems Inc., USA) and used SpO and FiOy to correct for intrapulmonary shunts. Invasively, using a pulmonary artery catheter (Hands-Off Thermodilution Catheter, Arrow Co., USA) and 10 ml of iced 5% dextrose, an average of three consecutive TDCO was measured during end- expiration and compared with corresponding RBCO during pre-CPB and post-CPB for a total of 6 times respectively. Data was analyzed by paired T-test with significance set at P value < 0.05. Results: Pre-CPB paired T-test analysis revealed no significant difference between partial rebreathing and bolus thermodilution cardiac output measurements. On the other hand, post-CPB differences between the two methods were significant (P < 0.05) and tended to decrease with time. Similarly, Pa-ETCO₂ was mcreased abnormally after CPB, then decreased with time to a normal value. Conclusion: Post-CPB, partial rebreathing cardiac output did not correlate well with the thermodilution cardiac output. As a cause for the differences of the two cardiac output measurements, we could consider a thertnal noise during thermodilution and an inadequate correction for the shunts in partial rebreathing measurements, but further investigation is needed.

Comparison of continuous with intermittent bolus thermodilution cardiac output measurements

Few complete studies have been published to validate the agreement between continuous cardiac output and intermittent thermodilution cardiac output. To analyze the agreement between cardiac output measurements by the continuous thermodilution method and the intermittent bolus thermodilution method, using a continuous cardiac output catheter in postoperative cardiothoracic surgery patients. A convenience sample of 14 adult cardiothoracic surgical patients with thermodilution pulmonary artery catheters placed preoperatively was used. A total of 214 comparison measurements of cardiac output by both the continuous and intermittent thermodilution methods were taken on patient admission to the critical care unit, every 4 hours, and with any change greater than 10% from baseline readings. The intraclass correlation between continuous cardiac output and intermittent cardiac output was .89. The limits of agreement were -1.34 to 1.18 L/min, indicating that in 95% of readings the difference between continuous cardiac output and intermittent cardiac output were within this range. The continuous cardiac output monitoring method shows clinically acceptable agreement with the intermittent cardiac output method.