Pulmonary Artery Thermodilution Research Articles

Lack of agreement between pulmonary arterial thermodilution cardiac output and the pressure recording analytical method in postoperative cardiac surgery patients

Pulse-contour analysis method (PCM) cardiac output (CO) monitors are increasingly used for CO monitoring during anaesthesia and in the critically ill. Very recently, several systems have been introduced that do not need calibration; among them the pressure recording analytical method (PRAM). Sparse data comparing the accuracy of the PRAM-CO with conventional thermodilution CO (ThD-CO) in cardiac surgery patients are available. In this prospective comparison study, paired CO measurements with a pulmonary artery catheter and a PRAM monitoring set were obtained 20-30 min apart (t1, t2) in 23 extubated patients on the first postoperative day after cardiac surgery. Data were analysed by the Bland-Altman method. A total of 46 paired CO measurements (23 for each interval) were collected. The Bland-Altman analysis showed a mean difference (bias) of 0.0 litre min(-1) and limits of agreement (1.96 sd) of 4.53 to -4.54 litre min(-1) [upper 95% confidence interval (CI), 3.26-5.80; lower 95% CI, -5.8 to -3.27]. The percentage error (1.96 sd/mean of the reference method) was 87%. These results question the reliability of the PRAM technology for the determination of CO in postoperative cardiac surgery patients.

Validation of cardiac output measurement by ultrasound dilution technique with pulmonary artery thermodilution in a pediatric animal model.

Novel COstatus system (Transonic Systems, Inc., NY), based on ultrasound dilution (UD), works off in situ arterial and central venous catheters in pediatric patients to measure cardiac output (CO). The purpose of the present study was to validate CO measurement by UD (COUD) with pulmonary artery (PA) thermodilution (COTD) in a prospective animal study. Ten anesthetized pigs (16-45 kg) were instrumented with pediatric PA, central venous, and peripheral artery catheters. For COUD measurements, normothermic saline (0.5-1.0 ml/kg body weight, up to a maximum of 30 ml) was injected into the venous limb of an arteriovenous loop that was connected between in situ catheters. For COTD measurements, 5-10 ml cold saline was injected into the PA catheter. Sixty-four averaged sets were obtained for comparison. COTD mean was 2.98 ± 1.21 l/min (range 1.33-6.29), and COUD mean was 2.68 ± 1.16 l/min (range 1.33-5.85). This study yielded a correlation r = 0.96, COUD = 0.91*(COTD) - 0.04 l/min; bias was 0.3 l/min with limits of agreement as -0.39 to 0.99 l/min; and the percentage error was 23.73% between the methods. CO measurements by UD agreed well with thermodilution measurements in the pediatric swine model.

Cardiac Output Determination From Endotracheally Measured Impedance Cardiography: Clinical Evaluation of Endotracheal Cardiac Output Monitor

To evaluate the accuracy, precision, and trending of a new endotracheally sourced impedance cardiography-based cardiac output (CO) monitor (ECOM; ConMed Corp, Irvine, CA). Two university hospitals. Thirty patients scheduled for elective coronary artery bypass graft (CABG) surgery. All patients received a pulmonary artery catheter (PAC), arterial catheter, endotracheal CO monitor (ECOM), endotracheal intubation, and transesophageal echocardiographic monitoring. ECOM CO was compared with CO measured with pulmonary artery thermodilution, and left ventricular CO measured with transesophageal echocardiography. One hundred forty-five pairs of triplicate CO measurements using intermittent bolus pulmonary artery thermodilution (TD) and ECOM were compared at 5 distinct time points: postinduction, postinduction passive leg raise, poststernotomy, post-CABG completion, and post-chest closure. Eighty-seven pairs of triplicate CO measurements using transesophageal echocardiography were obtained at 3 time points: postinduction, post-CABG completion, and post-chest closure and compared with ECOM- and PA-derived CO measurements. The measurements at each time point were compared by using Bland-Altman and polar plot analyses. The mean CO ranged from 2.16 to 9.41 L/min. ECOM CO, compared with TD CO, revealed a bias of 0.02 L/min, 95% limits of agreement of -2.26 to 2.30 L/min, and a percent error of 50%. ECOM CO showed trending with TD CO with 91% and 99% of values within 0.5L/min and 1 L/min limits of agreement, respectively. ECOM CO, compared with TEE CO, revealed a bias of -0.25 L/min, 95% limits of agreement of -2.41 to 1.92 L/min, and a percent error of 48%. ECOM CO showed trending with TEE CO with 83% and 95% of values within 0.5L/min and 1 L/min limits of agreement, respectively. ECOM CO shows an acceptable bias with wide limits of agreement and a large percent error when compared with TD CO or TEE CO; however, it shows acceptable trending of CO to both modalities in patients undergoing cardiac surgery. Further studies are required to evaluate ECOM in other patient populations and clinical situations.

Comparison of cardiac output estimation by FloTrac/Vigileo TM and intermittent pulmonary artery thermodilution in patient with Takayasu arteritis

Comparison of cardiac output estimation by FloTrac/Vigileo ^TM and intermittent pulmonary artery thermodilution in patient with Takayasu arteritis

Determination of the Precision Error of the Pulmonary Artery Thermodilution Catheter Using an In Vitro Continuous Flow Test Rig

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. 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. 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. 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.

Flow-Regulated Extracorporeal Arteriovenous Tubing Loop for Cardiac Output Measurements by Ultrasound Velocity Dilution: Validation in Post-Cardiac Surgery Intensive Care Unit Patients

Assessment of cardiac output (CO) is crucial in the management of the critically ill, especially in post cardiac surgery intensive care unit (ICU) patients. In this study, we validated CO measured by the novel ultrasound dilution (COUD) with those measured by pulmonary artery (PA) thermodilution (COTD) in 26 adult post cardiac surgery patients. For COUD, blood was circulated through an extracorporeal arteriovenous (AV) loop from the radial artery catheter to the introducer of PA catheter for 5-8 minutes. Three to four injections of 25 ml body temperature isotonic saline were performed into the venous limb of the AV loop. For COTD, five injections of 10 ml ice cold saline were performed. A total of 77 COUD and COTD measurement sets were compared. Cardiac output measured by thermodilution ranged from 3.28 to 9.4 L/min, whereas COUD ranged from 2.85 to 10.1 L/min. The correlation between the methods was found to be r = 0.91, COUD = 0.93(COTD) + 0.42 L/min. Bias and precision (mean difference ± 2SDs) was -0.004 ± 1.34 L/min between the two methods. The percentage error (2SD/mean) was 22.2%, which is below the clinically acceptable limit (<30%). Cardiac output measured by ultrasound dilution and thermodilution methods agreed well in post cardiac surgery ICU patients and hence can be interchangeably used.

Pulse contour cardiac output derived from non‐invasive arterial pressure in cardiovascular disease

Pulse contour methods determine cardiac output semi-invasively using standard arterial access. This study assessed whether cardiac output can be determined non-invasively by replacing the intra-arterial pressure input with a non-invasive finger arterial pressure input in two methods, Nexfin CO-trek and Modelflow , in 25 awake patients after coronary artery bypass surgery. Pulmonary artery thermodilution cardiac output served as a reference. In the supine position, the mean (SD) differences between thermodilution cardiac output and Nexfin CO-trek were 0.22 (0.77) and 0.44 (0.81) l.min(-1) , for intra-arterial and non-invasive pressures, respectively. For Modelflow, these differences were 0.70 (1.08) and 1.80 (1.59) l.min(-1) , respectively. Similarly, in the sitting position, differences between thermodilution cardiac output and Nexfin CO-trek were 0.16 (0.78) and 0.34 (0.83), for intra-arterial and non-invasive arterial pressure, respectively. For Modelflow, these differences were 0.58 (1.11) and 1.52 (1.54) l.min(-1) , respectively. Thus, Nexfin CO-trek readings were not different from thermodilution cardiac output, for both invasive and non-invasive inputs. However, Modelflow readings differed greatly from thermodilution when using non-invasive arterial pressure input.

Effects of Extravascular Lung Water on the Measurement of Transpulmonary Thermodilution Cardiac Output in Acute Respiratory Distress Syndrome Patients

Transpulmonary thermodilution cardiac output is used in calculating aortic impedance for calibrating the pulse-contour analysis and is applied to calculate extravascular lung water (EVLW). Whether pulmonary edema affects the accuracy of transpulmonary thermodilution is controversial. This study aimed to investigate the effects of extravascular lung water index (EVLWI) on the transpulmonary thermodilution measurement in acute respiratory distress syndrome (ARDS). A prospective study. The medical intensive care unit of one medical center. Twenty-four ARDS patients. The continuous pulmonary artery thermodilution cardiac index (CCIpa) and the bolus transpulmonary thermodilution cardiac index (BCItp) data were recorded at baseline and repeated immediately and at 2, 4, and 6 hours after volume expansion with a 500-mL infusion of 10% pentastarch (hydroxyethyl starch 200/0.5) at a rate of 10 mL/kg/h. A total of 120 paired CI measurements were analyzed. Linear regression analysis showed a close correlation between BCItp and CCIpa (R = 0.87). The mean BCItp was higher than CCIpa, and the Bland-Altman analysis revealed a bias of 0.51 ± 0.78 L/min/m(2). The limits of agreement (2 standard deviations) was 1.66 L/min/m(2) (+2.07 and -1.05 L/min/m(2)), and the percentage error was 31.5%. Levels of EVLWI negatively correlated with the difference between BCItp and CCIpa (R = -0.19). In ARDS patients, the agreement between transpulmonary thermodilution and pulmonary artery thermodilution for cardiac output measurement is marginally acceptable. The severity of pulmonary edema expressed as EVLWI weakly and negatively correlates with the difference between BCItp and CCIpa derived from the two techniques.

Comparison of the Endotracheal Cardiac Output Monitor to Thermodilution in Cardiac Surgery Patients

To compare cardiac output (CO) measurements from a novel endotracheal bioimpedance cardiac output monitor device (ECOM; ConMed, Irvine, CA) to simultaneous pulmonary artery thermodilution (TD) CO. Prospective study. One academic hospital. Forty volunteer patients undergoing cardiac surgery. Intraoperative CO measurements. Simultaneous comparative data points were collected from ECOM and TD at 4 periods: post-induction, post-sternotomy, post-cardiopulmonary bypass, and post-chest closure. The mean CO(TD) was compared with CO(ECOM) for each operative period then assessed for agreement by linear regression, Bland-Altman analysis, and percent error methods. There were 35 men (87.5%) with a mean age of 66 ± 10.7 years in the present study population. R values (p value) for the 4 time periods were 0.50 (0.002), 0.33 (0.035), 0.42 (0.007), and 0.48 (0.002). Bias and 95% limits of agreement in L/min were -0.11 (-2.40 to 2.18), 0.04 (-2.57 to 2.65), -0.06 (-2.86 to 2.74), and 0.02 (-2.42 to 2.45). Percent errors of the 4 time periods were 51%, 53%, 50%, and 48%. ECOM did not adequately agree with TD in patients undergoing cardiac surgery.

Fortuitous Discovery of Partial Uhl Anomaly in a Male Adult

We report the case of a 44-year-old man referred to our institution for suspicion of arrhythmogenic right ventricular (RV) cardiomyopathy. Both familial and personal medical histories were unremarkable, except the notion of a slight unexplored heart murmur during childhood. He decided to undergo a “40s” medical checkup. On presentation to the general practitioner, he had described a slight fatigue for 8 months without concomitant stress. Physical examination revealed no abnormality. ECG showed a type I atrioventricular block and a complete right bundle-branch block (Figure 1A). Transthoracic echocardiography showed an unusual left ventricle (LV) with a leftward curveted interventricular septum (IVS) and preserved global and segmental LV systolic function, suggestive of high systolic RV pressure or takotsubo cardiomyopathy (Figure 1B and Movie I in the online-only Data Supplement). However further analysis showed normal systolic pulmonary artery pressure and LV filling pressures. The apical 4-chamber view showed an abnormal RV with an aneurysm-like shape of the basal lateral free wall (Figure 1B and Movie II in the online-only Data Supplement) but with normal kinetics. A first cardiac magnetic resonance image showed biventricular abnormalities, particularly focused on RV wall motion, which justified additional morphological investigations. No abnormal pulmonary venous return was noticed. Invasive coronary angiogram was normal. The patient was later referred to our unit by his attending cardiologist and underwent invasive hemodynamics and biventricular contrast angiography. Cardiac index (pulmonary artery thermodilution) and biventricular volumes were normal. Blood gas content analysis disclosed an intracardiac shunt. RV angiography (Figure 2A and 2B) showed a truncated RV apex and the absence of trabeculations in the anteroapical and inferoapical zones, therefore characterized by a smooth …

Comparison of cardiac output values; pulse contour methods against thermodilution technique

We evaluated the performance of the FloTrac/Vigileo system (FCO) and simultaneously obtained cardiac output (CO) values with the PiCCOplus (PCO), LiDCO™plus (LCO), Vigilance continuous pulmonary artery thermodilution (CCO) against the intermittent pulmonary artery thermodilution technique (ICO).

Ventilation and Haemodynamic Indicators in Spontaneously Breathing Pigs under General Anaesthesia

The aim of this study was to obtain ventilation and haemodynamic data of healthy piglets under general anaesthesia for future patho-physiological experimental studies. A total of 34 domestic piglets of the Czech Black Pied (Přeštice) breed were used in the study. The animals (male to female ratio 8 : 9) were six weeks old and their average body mass was 22 kg. A general anaesthetic (fentanyl and azaperon) was introduced via a pulmonary artery catheter and the spontaneously breathing animals were monitored for 60 min. Cardiac output and haemodynamic indicators were established using intermittent pulmonary artery thermodilution. Blood gas data were deduced using fan dynamic parameters of ventilation and ventilation indices. The study yielded reliable data of dynamic lung indicators (p &lt; 0.05); e.g. the tidal volume 6.00 ± 0.82 ml/kg, hypoxemic index 350.47 ± 42.50 mmHg, lung compliance 0.63 ± 0.12 ml/cmH2O/kg, and haemodynamic indicators (p &lt; 0.01) such as cardiac output 2.12 ± 0.75 l/min, pulmonary vascular resistance 3.92 ± 0.52 and systemic vascular resistance 15.8 ± 6.81 Woods units. Reliable data regarding lung dynamics, cardiac output, preload and afterload of both heart ventricles in spontaneously breathing healthy piglets under general anaesthesia were achieved.

Comparison of electrical velocimetry and transthoracic thermodilution technique for cardiac output assessment in critically ill patients

The results of studies validating the assessment of cardiac output by pulmonary artery thermodilution and a modified algorithm using thoracic bioimpedance/electrical velocimetry in patients undergoing elective cardiac surgery are conflicting. The present observational study was designed to detect whether electrical velocimetry measurements are comparable to transthoracic thermodilution in septic patients after major general surgery. Cardiac output was assessed simultaneously by thoracic bioimpedance measurement/electrical velocimetry and transthoracic thermodilution technique (PiCCO) in 30 patients with severe systemic inflammatory response syndrome or sepsis with haemodynamic instability being treated in the surgical intensive care unit of an university hospital. Thirty simultaneous measurements were taken with both methods. The Bland-Altman analysis of agreement revealed a bias of -0.3 l min(-1) with a precision of +/-1.9 l min(-1) and wide limits of agreement (-4.1-3.5 l min(-1)). The percentage error was 54%. There was poor agreement between the values of cardiac output estimation by transthoracic thermodilution and those by electrical velocimetry. Electrical velocimetry could not replace invasive monitoring in this trial.

Cardiac output derived from arterial pressure waveform

Cardiac output (CO) and other flow-based hemodynamic variables have become increasingly important to guide treatment of patients undergoing major surgery with expected fluid shifts in the operating room as well as critically ill ICU patients. Established techniques such as pulmonary artery thermodilution, however, might not be justified in all of these patients. As arterial access is commonly available, less-invasive arterial pressure waveform-based CO devices are becoming more and more popular. Many studies dealing with arterial pressure waveform-based CO have emerged in recent years providing additional information with regard to accuracy of the different commercially available devices. Furthermore, methods of comparative CO studies have been recently brought into question. Although there are differences in invasiveness and the need for external calibration, all available devices provide parameters for enhanced hemodynamic monitoring. Initial validation studies of the more established techniques such as the pulse contour cardiac output (PiCCO) or LiDCO were recently met with less enthusiasm, whereas the initially disappointing validation studies of the FloTrac/Vigileo device had encouraging results after software updates. The pressure recording analytical method (PRAM) technique has not so far been sufficiently evaluated to be able to come to a conclusion. Further investigation is required with regard to the ability of the arterial pressure waveform-based methods to guide goal-directed therapy.

Inotropic Support During Experimental Endotoxemic Shock: Part I. The Effects of Levosimendan on Splanchnic Perfusion

Septic shock may cause splanchnic hypoperfusion. We hypothesized that levosimendan would improve systemic and hepatosplanchnic perfusion during endotoxemic shock. In 16 anesthetized pigs (31.4 +/- 3.4 kg), a jugular vein, a carotid artery, the pulmonary artery (thermodilution), the portal vein, and a hepatic vein were cannulated for hemodynamic monitoring and blood sampling. Ultrasonic flowprobes were placed around the portal vein, the hepatic artery, and the superior mesenteric artery (SMA). In addition to 30 mL/kg of dextran 70 given before baseline, all animals received 10 mL x kg(-1) x h(-1) of IV fluids throughout the experiment. An endotoxin infusion (2 microg x kg(-1) x h(-1)) was given for 300 min; 100 min after the start of endotoxin, the pigs were randomized to receive levosimendan (50 microg x kg(-1) x h(-1), n = 8) or placebo (n = 8). To evaluate the isolated effects of endotoxemia, all data before randomization were pooled into one group. Data were analyzed by analysis of variance and presented as mean +/- sem. Endotoxemia (t = 90 min, pooled data) decreased systemic vascular resistance (SVR, 2526 +/- 203 to 1946 +/- 122 dyn x s x cm(-5), P = 0.003) and mean arterial blood pressure (MAP, 109 +/- 6 to 84 +/- 3 mm Hg, P < 0.05), whereas heart rate (66 +/- 4 to 98 +/- 8 bpm), and mean pulmonary arterial pressure (MPAP, 20 +/- 1 to 38 +/- 2 mm Hg) increased (P < 0.001). Cardiac output (CO, 3.4 +/- 0.2 L/min) and systemic oxygen delivery (414 +/- 33 mL/min) were unchanged, but blood flows in the SMA (575 +/- 34 to 392 +/- 38 mL/min) and the portal vein (881 +/- 62 to 568 +/- 39 mL/min) decreased (P < 0.001). Although hepatic arterial blood flows increased (36 +/- 8 to 219 +/- 38 mL/min), gut (114 +/- 11 to 84 +/- 7 mL/min) and hepatic (94 +/- 11 to 67 +/- 8 mL/min) oxygen deliveries decreased (P < 0.05). At t = 300 min, the levosimendan group showed lower MPAP (39 +/- 3 vs 49 +/- 2 mm Hg, P = 0.025), lower SVR (2158 +/- 186 vs 3069 +/- 370 dyn x s x cm(-5), P = 0.052), and lower MAP (55 +/- 9 vs 87 +/- 9 mm Hg, P < 0.001) than the control group. In both groups, CO, portal vein, and hepatic arterial blood flows decreased (P < 0.001); the mean values for the levosimendan group at t = 300 min were 2.0 +/- 0.4 L/min, 390 +/- 83 mL/min, and 36 +/- 12 mL/min, respectively. SMA blood flow decreased only in the levosimendan group (432 +/- 40 to 320 +/- 78 mL/min, P < 0.001), whereas gut oxygen delivery decreased in the levosimendan (85 +/- 12 to 63 +/- 12 mL/min, P < 0.001) and in the control (83 +/- 6 to 59 +/- 3 mL/min, P = 0.03) groups. Levosimendan administered after the establishment of endotoxemic shock to pigs receiving moderate fluid resuscitation prevented further increases in MPAP and maintained a low SVR. There were, however, no improvements in CO, MAP decreased, and levosimendan neither prevented the development of circulatory shock nor improved hepatosplanchnic perfusion.

Uncalibrated Radial and Femoral Arterial Pressure Waveform Analysis for Continuous Cardiac Output Measurement: An Evaluation in Cardiac Surgery Patients

Arterial pressure waveform analysis is a less invasive alternative to the pulmonary artery catheter for continuous cardiac output (CO) measurement. Uncalibrated and calibrated systems are actually available (ie, the FloTrac/Vigileo system [Edwards Lifesciences, Irvine, CA] and the PiCCOplus system [Pulsion Medical Systems, Munich, Germany]). According to the FloTrac/Vigileo manufacturer, reliable measurements can be performed using any existing arterial catheter. The aim of this study was to evaluate CO determined by the FloTrac/Vigileo system using a radial (FCO(radial)) and femoral arterial catheter (FCO(femoral)) as well as the PiCCOplus system (PCO). Intermittent pulmonary artery thermodilution (ICO) was used as primary reference technique. A prospective clinical study. A teaching hospital, single center. Twenty-six cardiac surgery patients. Perioperative CO measurements. CO was assessed at predefined measurement points. FCO(radial), FCO(femoral), and PCO were recorded after the induction of anesthesia, after sternotomy, at skin closure, after intensive care unit transfer, and during intensive care unit stay 12 and 24 hours after study initiation. ICO was determined as the mean of 3 bolus injections. Bland-Altman analysis revealed comparable mean bias and limits of agreement for FCO(radial), FCO(femoral), and PCO when compared with ICO. There was a decreased agreement for all devices in the postoperative period. However, a consistently close agreement was observed for the direct comparison between FCO(radial) and FCO(femoral). Performance of the FloTrac/Vigileo system via radial as well as femoral access and the PiCCOplus monitoring for cardiac output measurement were comparable when tested against intermittent thermodilution in cardiac surgery patients.

Uncalibrated arterial pressure waveform analysis for less-invasive cardiac output determination in obese patients undergoing cardiac surgery

Uncalibrated arterial waveform analysis (FloTrac/Vigileo) uses standard arterial access to determine cardiac output (CO). Calculations are based on arterial waveform characteristics in combination with patient characteristic data to estimate individual arterial compliance. It has been shown that obesity is associated with altered arterial compliance independently of other risk factors. We conducted this study to assess the validity of measuring CO by the FloTrac/Vigileo device in obese patients undergoing cardiac surgery in comparison with bolus thermodilution technique. Fifteen obese patients with a BMI of > or = 30 and 23 non-obese patients (BMI 18-25) undergoing coronary artery bypass grafting (CABG) were included. Simultaneous CO measurements by bolus thermodilution and the FloTrac/Vigileo device (software version 1.10) were obtained intraoperatively after induction of anaesthesia, before cardiopulmonary bypass (CPB), after CPB, and after sternal closure. Measurements in the intensive care unit (ICU) were performed upon arrival in the ICU, after 4, 8, and 24 h after surgery. CO was indexed to the body surface area (cardiac index, CI). The analysis of 262 data pairs revealed a bias and precision of 0.19 and +/-0.66 litre min(-1) m(-2), resulting in a percentage error of 26.6%. Thermodilution CI values ranged from 1.1 to 4.2 litre min(-1) m(-2) [mean 2.4 (0.52) litre min(-1) m(-2)]. Subgroup analysis resulted in a percentage error of 29.8% in obese patients and 24.4% in patients with normal BMI. The semi-invasive FloTrac/Vigileo device was found to adequately agree with bolus pulmonary artery thermodilution in both obese and non-obese patients undergoing CABG.

Preoperative haemodynamic parameters and the immediate outcome after open repair of ruptured abdominal aortic aneurysms

The aim of this study was to evaluate the impact of preoperative cardiac function and haemodynamic parameters on the immediate outcome after repair of ruptured abdominal aortic aneurysm (RAAA). This is a retrospective review of 68 consecutive patients who underwent emergency repair of RAAA. Baseline pulmonary artery pressure, cardiac index, oxygen saturation and pulse rate were measured and recorded immediately after insertion of a pulmonary artery thermodilution catheter and before anaesthesia induction. The in-hospital mortality rate was 39.7%. The area under the receiver operating characteristic (ROC) curve of cardiac index was 0.74 (95% CI 0.61-0.86), of stroke volume index was 0.78 (95% CI 0.67-0.89) and for oxygen delivery 0.72 (95% CI 0.60-0.84) for prediction of in-hospital death. The best cut-off values of cardiac index was 2.7 l/min/m(2) (18.8% vs. 58.3%, OR 6.07, 95% CI 2.00-18.37), of stroke volume index was 27 ml/m(2) (23.1% vs. 62.1%, OR 5.46, 95% CI 1.90-15.70) and of oxygen delivery was 370 ml/min/m(2) (17.9% vs. 56.4%, OR 5.05, 95% CI 1.87-18.91). Multivariate analysis showed that patient's age (P=0.01, OR 1.23, 95% CI 1.05-1.44), stroke volume index (P=0.018, OR 0.89, 95% CI 0.81-0.98), and shock (P=0.007, OR 14.20, 95% CI 2.09-96.67) were independent predictors of in-hospital death. This study suggests that impaired cardiac function and suboptimal oxyhaemodynamic parameters are important determinants of death after repair of RAAA.

Pulse contour cardiac output: an evaluation of the FloTrac method

The aim of this study was to determine the agreement between pulmonary artery thermodilution (PA-TD) and a new pulse contour method (PCM), FloTrac/Vigileo version 1.0, and to asses the ability of FloTrac to track sudden changes in cardiac output. Cardiac output was determined twice after induction of anaesthesia, but before cardiac surgery, with both PA-TD and a PCM in order to determine the precision of both methods. The bias and agreement between the two methods were calculated using Bland-Altman analysis. Postoperatively, in patients with heart rates under 60 beats min(-1), atrial pacing was initiated and cardiac output was determined before and after with both methods. Twenty-five patients were investigated. The precisions of PA-TD and the PCM were 0.35 (95% confidence interval +/-0.12) and 0.6 l min(-1) (95% confidence interval +/-0.21%). The bias between PA-TD and the PCM was -0.51 l min(-1) and the limits of agreement were +/-1.87 l min(-1) (95% confidence interval +/-0.39 and +/-0.66). The percentage error was 48%. The changes in cardiac output with atrial pacing were in the same direction in all nine patients. In this study, agreement between PA-TD and the PCM was poor, but the PCM was able to track the direction of pace-induced changes in cardiac output.

Comparison of a New Cardiac Output Ultrasound Dilution Method With Thermodilution Technique in Adult Patients Under General Anesthesia

The purpose of this study was to investigate the reliability of cardiac output (CO) measured by a new ultrasound dilution method (COud) in comparison with CO by pulmonary artery thermodilution (COtd) in adult patients undergoing surgery. A prospective study. A university hospital, single institutional. Twenty-nine adult patients undergoing abdominal surgery. After approval of the institutional ethics review board, 29 adult patients were evaluated. After induction, radial and pulmonary artery catheters were inserted. A disposable extracorporeal AV loop was connected between existing arterial and central venous catheters. Reusable ultrasound sensors that measure changes in blood ultrasound velocity after dilution by isotonic saline were clamped onto the arterial and venous limbs of the loop. Ultrasound dilution (UD) measurements (COstatus; Transonic Systems, Inc, Ithaca, NY) were obtained by injecting 30 mL of body-temperature isotonic saline into the venous limb of the AV loop. An average of 3 COud and 5 COtd was obtained for comparison. Bland-Altman plot and correlation analysis were used for statistical comparison. A total of 142 comparison measurements were obtained. The correlation coefficient between the 2 techniques was r = 0.91. Bland-Altman analysis did not produce any significant bias (bias = 0.02, standard deviation = 0.56). The percentage error of these data was 23.53%. COud measurements agreed well with COtd. The results of this study indicated that COud might be interchangeable with conventional COtd in perioperative adult patients.