Pulmonary Artery Thermodilution Research Articles

Assessment of cardiac output and volume load by transpulmonary thermodilution technique in immature pigs.

To assess the accuracy of cardiac output (CO) measured by transpulmonary thermodilution technique (TPTD)and explore the validity of intrathoracic blood volume index (ITBVI) for assessment of circulatory volume status. Ten immature pigs with a mean weight of (20.6±1.9)kg were studied during the conditions including normovolemia, hypervolemia, and hypovolemia. Simultaneous CO was measured in each condition using pulmonary artery thermodilution (PATD) method and TPTD. More specifically, CO (COPA) was determined with PATD, while CO (COTP) and ITBVI were determined with TPTD. All measurements were repeated 3 times. Central venous pressure (CVP) and heart rate were measured at the same time. The potential correlations of CVP and ITBVI with cardiac index (CI) and stroke volume index (SVI) in each blood volume status were analyzed. A total of 90 simultaneous measurements of COPA and COTP in 3 different blood volume conditions were made. The correlation coefficient between the two measurements was 0.977 (P<0.001) and the mean difference was (0.25±0.26)L/min (95%CI:0.20-0.30 L/min, P<0.001). The coefficient of variation of COTP was 3.7%, while COPA was 5.4%. Compared with those in normovolemia, CVP and ITBVI in hypervolemia significantly increased (P=0.002, 0.019), ITBVI in hypovolemia decreased significantly (P<0.001), and CVP in hypovolemia decreased insignificantly (P=0.05). Correlation analysis revealed a significant correlation between ITBVI with CI and SVI in normovolemia (r=0.741, P=0.014; r=0.885, P=0.001). In contrast, correlations between CVP with CI and SVI were poor. TPTD can accurately and precisely measure CO in different blood volume conditions. ITBVI measured by TPTD has better validity for the assessment of circulatory volume status than CVP.

Electrical bioimpedance cardiography: an old technology with new hopes for the future.

THE POSITIVE IMPACT of early goal-directed hemodynamic therapy on postoperative outcome increasingly has been investigated over the last few years in high-risk patients undergoing noncardiac and cardiac surgeries. 1 Phan T.D. Ismail H. Herior A.G. et al. Improving perioperative outcomes: Fluid optimization with the esophageal Doppler monitor, a meta-analysis and review. J Am Coll Surg. 2008; 207: 935-941 Abstract Full Text Full Text PDF PubMed Scopus (87) Google Scholar , 2 Hamilton M. Cecconi M. Rhodes A. A systematic review and meta-analysis on the use of preemptive hemodynamic intervention to improve postoperative outcomes in moderate and high-risk surgical patients. Anesth Analg. 2011; 112: 1392-1402 Crossref PubMed Scopus (593) Google Scholar , 3 Aya H.D. Cecconi M. Hamilton M. et al. Goal-directed therapy in cardiac surgery: A systematic review and meta-analysis. Br J Anaesth. 2013; 110: 510-517 Crossref PubMed Scopus (156) Google Scholar , 4 Goepfert M.S. Richter H.P. Eulenburg C.Z. et al. Individually optimized hemodynamic therapy reduces complications and length of stay in the intensive care unit: A prospective, randomized controlled study. Anesthesiology. 2013; 119: 824-836 Crossref PubMed Scopus (120) Google Scholar However, these preemptive strategies require advanced hemodynamic monitoring to assess cardiac output and stroke volume. The classic available tools (intermittent pulmonary arterial or transpulmonary thermodilution or esophageal Doppler), either invasive or operator-dependent and necessitating a learning curve, are not convenient for routine practice. Therefore, they remain insufficiently used among North American and European anesthesiologists. 5 Cannesson M. Pestel G. Ricks C. et al. Hemodynamic monitoring and management in patients undergoing high risk surgery: A survey among North American and European anesthesiologists. Crit Care. 2011; 15: R197 Crossref PubMed Scopus (208) Google Scholar Besides, new mini-invasive cardiac output devices have been developed commercially over the last decade. 6 Marik P.E. Noninvasive cardiac output monitors: A state-of the-art review. J Cardiothorac Vasc Anesth. 2013; 27: 121-134 Abstract Full Text Full Text PDF PubMed Scopus (205) Google Scholar Less accurate but more convenient and easy to use, they potentially could help the practitioners in promoting advanced hemodynamic monitoring and early goal-directed therapy at the bedside in high-risk patients in an attempt to further improve postoperative outcome. Among these mini-invasive technologies, thoracic electrical bioimpedance (TEB) has major theoretical advantages and could be of great clinical utility in the settings of anesthesiology, cardiology, and perioperative medicine. Despite extensive literature published over the last 50 years, TEB remains scarcely used by practitioners.

Mesure semi-invasive du débit cardiaque basé sur le contour du pouls: étude et analyse

The aim of this review was to provide a meta-analysis of all five of the most popular systems for arterial pulse contour analysis compared with pulmonary artery thermodilution, the established reference method for measuring cardiac output (CO). The five investigated systems are FloTrac/Vigileo(®), PiCCO(®), LiDCO/PulseCO(®), PRAM/MostCare(®), and Modelflow. In a comprehensive literature search through MEDLINE(®), Web of Knowledge (v.5.11), and Google Scholar, we identified prospective studies and reviews that compared the pulse contour approach with the reference method (n=316). Data extracted from the 93 selected studies included range and mean cardiac output, bias, percentage error, software versions, and study population. We performed a pooled weighted analysis of their precision in determining CO in various patient groups and clinical settings. Results of the majority of studies indicate that the five investigated systems show acceptable accuracy during hemodynamically stable conditions. Forty-three studies provided adequate data for a pooled weighted analysis and resulted in a mean (SD) total pooled bias of -0.28 (1.25) L·min(-1), percentage error of 40%, and a correlation coefficient of r=0.71. In hemodynamically unstable patients (n=8), we found a higher percentage error (45%) and bias of -0.54 (1.64) L·min(-1). During hemodynamic instability, CO measurement based on continuous arterial pulse contour analysis shows only limited agreement with intermittent bolus thermodilution. The calibrated systems seem to deliver more accurate measurements than the auto-calibrated or the non-calibrated systems. For reliable use of these semi-invasive systems, especially for critical therapeutic decisions during hemodynamic disorders, both a strategy for hemodynamic optimization and further technological improvements are necessary.

Measurements of cardiac output obtained with transesophageal echocardiography and pulmonary artery thermodilution are not interchangeable

Echocardiography is increasingly becoming an integrated tool for circulatory evaluation in the intensive care unit and the operating room. Therefore, it is imperative to know the reproducibility of measurements obtained by echocardiography. In this study, a comparison of cardiac output (CO) measurements obtained with transesophageal echocardiography (TEE) and pulmonary artery catheter (PAC) thermodilution (TD) was carried out to test the precision, accuracy and trending ability of CO measurements obtained with TEE. Twenty-five patients completed the study. Each patient was placed in the following successive positions: supine, head-down tilt, head-up tilt, supine, supine with phenylephrine administration, pace heart rate 80 beats per minute (bpm), pace heart rate 110 bpm. TEE CO and PAC CO were measured simultaneously. The agreement was analysed by Bland-Altman plots, and to assess trending ability, a polar plot was constructed. Both methods showed an acceptable precision 8% (PAC TD) and 16% (TEE). In comparison with PAC TD, the TEE was associated with a bias of -0.22 l/minute [95% confidence interval: -0.54; 0.10], wide limits of agreement (-1.73 l/minute; 1.29 l/minute), a percentage error of 38.6% and a trending ability with a radial degree of 53.6°, corresponding to a poor trending ability. In comparison, CO measurements obtained with TEE and PAC TD had wide limits of agreement, a larger percentage error than would be expected from the precision of the two methods, and a poor trending ability. Thus, TEE is not interchangeable with PAC TD for measuring CO.

Effects of Levosimendan on Glomerular Filtration Rate, Renal Blood Flow, and Renal Oxygenation After Cardiac Surgery With Cardiopulmonary Bypass

Acute kidney injury develops in a large proportion of patients after cardiac surgery because of the low cardiac output syndrome. The inodilator levosimendan increases cardiac output after cardiac surgery with cardiopulmonary bypass, but a detailed analysis of its effects on renal perfusion, glomerular filtration, and renal oxygenation in this group of patients is lacking. We therefore evaluated the effects of levosimendan on renal blood flow, glomerular filtration rate, renal oxygen consumption, and renal oxygen demand/supply relationship, i.e., renal oxygen extraction, early after cardiac surgery with cardiopulmonary bypass. Prospective, placebo-controlled, and randomized trial. Cardiothoracic ICU of a tertiary center. Postcardiac surgery patients (n=30). The patients were randomized to receive levosimendan, 0.1 µg/kg/min after a loading dose of 12 µg/kg (n=15), or placebo (n=15). The experimental procedure started 4-6 hours after surgery in the ICU during propofol sedation and mechanical ventilation. Systemic hemodynamic were evaluated by a pulmonary artery thermodilution catheter. Renal blood flow and glomerular filtration rate were measured by the renal vein retrograde thermodilution technique and by renal extraction of Cr-EDTA, respectively. Central venous pressure was kept constant by colloid/crystalloid infusion. Compared to placebo, levosimendan increased cardiac index (22%), stroke volume index (15%), and heart rate (7%) and decreased systemic vascular resistance index (21%), whereas mean arterial pressure was not affected. Levosimendan induced significant increases in renal blood flow (12%, p<0.05) and glomerular filtration rate (21%, p<0.05), decreased renal vascular resistance (18%, p<0.05) but caused no significant changes in filtration fraction, renal oxygen consumption, or renal oxygen extraction, compared to placebo. After cardiac surgery with cardiopulmonary bypass, levosimendan induces a vasodilation, preferentially of preglomerular resistance vessels, increasing both renal blood flow and glomerular filtration rate without jeopardizing renal oxygenation. Due to its pharmacodynamic profile, levosimendan might be an interesting alternative for treatment of postoperative heart failure complicated by acute kidney injury in postcardiac surgery patients.

The pulse pressure/heart rate ratio as a marker of stroke volume changes during hemorrhagic shock and resuscitation in anesthetized swine

Emergency physicians and anesthesiologists need accurate estimates of stroke volume when massive unexpected hemorrhage occurs. Using an animal model of hemorrhagic shock under general anesthesia, we hypothesized that the pulse pressure-heart rate ratio (PP/HR) would be an accurate marker of stroke volume changes during hemorrhage and resuscitation. In 16 swine under bispectral index-controlled, intravenous propofol-remifentanil anesthesia, pressure-controlled hemorrhagic shock was induced to achieve 30 mm Hg of mean arterial pressure, after which treatment was randomized to fluid (HES, n = 4), norepinephrine (NE, n = 4), both (HES + NE, n = 4), or neither (control, n = 4). Pulmonary artery thermodilution continuous cardiac output, stroke volume, and central arterial pressures were recorded at baseline (T0), after 30 minutes (T30) and 60 (T60) minutes of hemorrhage, during treatment (T90 and T120) and after blood retransfusion (T180). At T60, blood withdrawal was 995 (301) mL (38 [8] mL/kg), resulting in a 70% decrease in stroke volume and a 3.3-fold decrease in PP/HR (each p < 0.01). When stroke volume data pointed at T0, T30 and T60 were plotted against the various hemodynamic variables under study, the PP/HR ratio exhibited the strongest relationship to stroke volume (r = 0.72). The area under the receiver operating characteristic curve set to detect a 15% stroke volume decrease was larger for PP/HR (0.95 [0.94-0.97]) than for mean arterial pressure (0.91 [0.89-0.93]) (p < 0.013). During resuscitation in the HES and NE groups, correlation coefficients were significantly higher between stroke volume and PP/HR (0.75 [0.63-0.84] and 0.79 [0.67-0.86]) than between stroke volume and mean arterial pressure (0.52 [0.32-0.67], p = 0.042, and 0.49 [0.28-0.65], p = 0.0018, respectively). The PP/HR ratio was strongly related to stroke volume during hemorrhagic shock and resuscitation in anesthetized swine.

Aortic Occlusion Hemodynamic Attenuation With Valproic Acid

Objectives: Valproic acid (VPA; a histone deacetylase inhibitor) has demonstrated significant decreases in resuscitation requirements as well as minimizing pathologic physiology following short term aortic occlusion. The purpose of this study was to compare the cardiac and hemodynamic changes with VPA administration following supraceliac aortic occlusion. Methods: 19 swine were exposed to a 35% blood volume hemorrhage followed by a supraceliac aortic cross clamp only model with valproic acid (400 mg/kg) administered as a drip continuously during supraceliac aortic cross clamping (CC, n 1⁄4 9). Hemodynamics were measured with the use of arterial blood pressure monitor and a pulmonary artery thermodilution catheter. Results: 10 swine were divided into two equal groupssham and model. In this validation, hemodynamics were significantly different as measured after hemorrhage and cross clamp by mean arterial pressure (MAP; P 1⁄4 .024), heart rate (P < .001), cardiac index (CI; P 1⁄4 .005). In the comparison arm of control and cross clamp group, there was a significant attenuation in the adverse hemodyamic response with administration of VPA (n 1⁄4 9) during cross clamp (MAP 1⁄4 87 6 28 vs CC-122 6 43 mm Hg; P 1⁄4 .02; HR 1⁄4 124 6 23 vs CC-161 6 32 bpm; P 1⁄4 .01). Additionally, throughout the cross clamp application, there was a significantly decreased hyperdynamic response with the administration of VPA (Fig). Conclusions: VPA helps attenuate the adverse hyperdynamic cardiac response following a hemorrhagic event and subsequent aortic occlusion. The hemodynamic response appeared to be not only significant at each time interval, but sustained as cross clamp times increased. Additionally, VPA seemed to minimize pathologic hemodynamic variation and provide cardiac protection through minimizing cardiac stress and work of the heart during aortic occlusion. Author Disclosures: M. W. Causey: Nothing to disclose; M. Martin: Nothing to disclose; S. Miller: Nothing to disclose; N. Singh: Nothing to disclose.

Cardiac output monitoring in septic shock: evaluation of the third-generation Flotrac-Vigileo®

Continuous cardiac index (CI) monitoring is frequently used in critically ill patients. Few studies have compared the pulse contour-based device FloTrac/Vigileo to pulmonary artery thermodilution (PAC) in terms of accuracy for CI monitoring in septic shock. The aim of our study was to compare the third-generation FloTrac/Vigileo to PAC in septic shock. Eighteen patients with septic shock requiring monitoring by PAC were included in this study. We monitored CI using both FloTrac/Vigileo and continuous thermodilution (PAC-CI). Hemodynamic data were recorded every hour or every 2 min during fluid challenges. The primary endpoint was the global agreement of all CI-paired measurements determined using the Bland-Altman method adapted to replicated data. We tested the linearity of the bias by regression analysis, and compared the reactivity of the 2 techniques during fluid challenges. A receiver operating characteristic (ROC) curve analysis tested the ability of FloTrac/Vigileo to detect concordant and significative CI changes, using PAC-CI as the reference method. Overall, 1,201 paired CI measurements were recorded. The Bland-Altman analysis for global agreement of the 2 techniques showed a bias of -0.1 ± 2.1 L min(-1) m(-2) and a percentage error of 64 %. The overall correlation coefficient between PAC-CI and FloTrac/Vigileo CI was 0.47 (p < 0.01), with r(2) = 0.22. The area under the curve of the ROC curve for detecting concordant and significant changes in CI was 0.72 (0.53; 0.87). In our study, third-generation Flowtrac-Vigileo appears to be too inaccurate to be recommended for CI monitoring in septic shock.

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Introduction: Pulmonary artery catheters and thermodilution (PAC-TD) remain the gold standard for hemodynamic monitoring, particularly after cardiac surgery. However, the invasive nature of PAC-TD, combined with its lack of clinical efficacy and declining use, calls for increased use of non-invasive hemodynamic monitoring techniques. Electrical cardiometry(EC), a form of thoracic electrical bioimpedance, provides completely non-invasive hemodynamic monitoring. This study evaluated the reliability of EC compared to PAC-TD for continuous hemodynamic monitoring in post-operative patients. Hypothesis: EC provides reliable continuous cardiac index (CI) monitoring compared to PAC-TD in post-operative patients. Methods: Post-operative patients with indwelling PACs (Continuous Cardiac Output catheters, Vigilance monitor, Edwards) underwent simultaneous, continuous hemodynamic monitoring with EC (Aesculon monitor, Cardiotronic). Comparisons were made between hourly PAC-TD and EC determinations of CI. EC CI values were averaged from one minute readings ±6 minutes centered on the hour. Bland-Altman analysis was performed for each individual patient’s data. Bias (mean difference between PAC-TD- and EC-derived CI) and percentage error (2SD of bias/mean CI) for each patient were calculated. Variance (coefficient of variation) over the entire monitoring period for each patient was calculated. Data are mean±SD. Results: 30 patients (cardiac surgery 29, vascular surgery 1) were monitored for 33 ± 19 hours. Bias was -0.7 ± 1 L/min/m2 and percentage error was 39 ± 12%. 23 (77%) of 30 patients had a percentage error < 40%. Coefficients of variation for PAC-TD and EC were 0.15 ± 0.04 and 0.14 ± 0.05, respectively (P = NS). Conclusions: EC monitoring of CI demonstrated good correlation with PAC-TD in post-operative patients. While a percentage error < 30% represents the ideal, clinically-acceptable limit of agreement between two hemodynamic monitoring techniques (Critchley and Critchley), many studies report values up to 40%. Our relatively small bias would generally be considered clinically acceptable and the low variance indicates reliable measurements. Our study supports EC as a reliable non-invasive method of continuous hemodynamic monitoring.

Effects of cardiac output levels on the measurement of transpulmonary thermodilution cardiac output in patients with acute respiratory distress syndrome

Transpulmonary thermodilution cardiac output (CO) correlates closely with pulmonary artery (PA) thermodilution CO. Levels of CO may contribute to varying amounts of thermal indicator loss and recirculation during thermodilution CO measurement. This study aimed to investigate the effects of CO levels on the agreement between transpulmonary and PA thermodilution CO in patients with acute respiratory distress syndrome (ARDS). Twenty-two patients with ARDS were prospectively enrolled. Paired bolus transpulmonary thermodilution cardiac index (BCItp) and continuous PA thermodilution cardiac index (CCIpa) 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 (HES 200/0.5). One hundred and ten paired cardiac index measurements were recorded and divided into 4 quartiles from the lowest to the highest CCIpa. The mean BCItp was higher than CCIpa, and the Bland and Altman analysis revealed a mean (SD) bias of 0.57 (0.75) L L min(-1) m(-2). The limits of agreement (2SD) were +2.07 to -0.93 L min(-1) m(-2). BCItp correlated closely with CCIpa (R = 0.887). CCIpa negatively correlated with the difference between BCItp and CCIpa (R = -0.26). The bias of quartile 1 with the least CCIpa was significantly greater than those of the three other quartiles. In patients with ARDS, transpulmonary thermodilution is a clinically acceptable and interchangeable alternative to PA thermodilution for CO measurement. Levels of CO weakly and negatively correlate with the difference between BCItp and CCIpa. There is greater overestimation of BCItp over CCIpa in low than in high CO states. Diagnostic study, level II.

Individualizing hemodynamic optimization during the management of circulatory collapse

The best method of hemodynamic monitoring to guide the resuscitation and management of the critically ill patient is unclear. The evaluated article presents data from a prospective randomized controlled trial that recruited 120 shocked patients (n = 60 in each arm) to compare volume-limited versus pressure-limited hemodynamic management. Patients were randomized into two protocolized fluid therapy algorithms using either the upper limits of hemodynamic indices of arterial pulse contour cardiac output and transpulmonary thermodilution (TPTD) analysis (extra vascular lung water <10 ml/kg and global end-diastolic volume index 850 ml/m2) or pulmonary artery catheter pressures (<18–20 mmHg). Primary outcomes were ventilator-free days, duration of mechanical ventilation, intensive care unit and hospital stay. Secondary outcomes included sequential organ failure assessment scores and mortality. No benefit was found between pulmonary artery catheter and TPTD in the primary outcomes; interestingly, the nonseptic patients who were monitored with TPTD spent longer on mechanical ventilation and in the intensive care unit.

Comparison of pulse contour versus pulmonary artery thermodilution cardiac output in patients undergoing elective open abdominal aortic aneurysm repair

Comparison of pulse contour versus pulmonary artery thermodilution cardiac output in patients undergoing elective open abdominal aortic aneurysm repair

Clinical evaluation of a new tracheal impedance cardiography method

Non-invasive cardiac output measurement by means of impedance cardiography has been evaluated before, and agreement with other methods has been variable. We decided to study a newly developed tracheal impedance device, that is claimed to be more accurate and reliable. This incorporates new software and mathematical formulae, that are designed to reduce signal noise from diathermy, leading to improved accuracy. In 25 cardiothoracic surgery patients, simultaneous measurements were performed using both pulmonary artery thermodilution and the tracheal impedance device, at five peri-operative time points: before skin incision; after weaning from cardiopulmonary bypass; after sternal closure; and 30 min and 2 h after arrival in the intensive care unit. Mean cardiac output, bias and 95% limits of agreement were 5.3, 0.03 and -2.8 to 2.8 l.min(-1) , respectively. Tracheal impedance showed good correlation with measurement trends using thermodilution in 88% of measurements, with a mean (95% limit of agreement) angular bias of -9.0° (-83.3 to 65.3°). However, the wide limits of agreement and high percentage error of 53% that were apparent in this study mean that, in its present guise, tracheal impedance is not an acceptable alternative to thermodilution in cardiac surgical patients.

Cardiac Output Derived From Arterial Pressure Waveform Analysis: Validation of the Third-Generation Software in Patients Undergoing Orthotopic Liver Transplantation

BackgroundThe upgraded third-generation software (version 3.02) for the FloTrac/Vigileo system has been developed to particularly improve the accuracy of cardiac output (CO) measurements in hyperdynamic conditions. The aim of our study was to compare the CO values obtained using the FloTrac/Vigileo system during orthotopic liver transplantation (OLT) with those obtained in the same circumstances using a Swan-Ganz catheter (bolus thermodilution method). MethodsTwenty consecutive recipients scheduled for OLT were studied. Simultaneous CO values measured by both devices were obtained at 10 predefined time points throughout the surgery. A percentage error of not more than 30% was established as the criterion for device interchangeability. ResultsA total of 200 paired measurements were obtained. The CO values derived from the FloTrac/Viligeo ranged from 2.8 to 10.9 L/min, with a mean of 5.91 ± 1.81 L/min. The values from bolus thermodilution ranged from 2.2 to 13.2 L/min, with a mean of 6.12 ± 2.07 L/min. The bias was 0.22, and the limits of agreement were −3.13 to 3.56 L/min. The percentage error between the FloTrac/Viligeo and bolus thermodilution measurements was 54.93%. The percentage errors of paired measurements in three surgical phases by subgroup analysis were 43.50% (dissecting phase), 62.9% (anhepatic phase), and 56.05% (reperfusion phase), respectively. ConclusionCO measurements obtained using the less invasive arterial waveform FloTrac/Vigileo system upgraded with the third-generation software had poor intraoperative agreement with pulmonary artery thermodilution CO measurements in patients undergoing OLT.

Effects of cardiac output levels on the measurement of transpulmonary thermodilution cardiac output in patients with acute lung injury

Transpulmonary thermodilution cardiac output (CO) correlates closely with pulmonary artery (PA) thermodilution CO. Levels of CO may contribute varying amounts of thermal indicator loss and recirculation during thermodilution CO measurement. This study aimed to investigate the effects of CO levels on the agreement between transpulmonary and PA thermodilution CO in acute lung injury (ALI) patients.

Ultrasound dilution

Cardiac output is a useful measure of myocardial performance. Cardiac output monitoring is frequently performed in critically ill adults to guide physicians' treatment strategies. However, standard methods of determining cardiac output in children are not without risk and can be problematic secondary to their invasive nature and other technical problems. The COstatus system (Transonic Systems, NY), which is based on ultrasound dilution technology, works off in situ catheters and uses an innocuous indicator to allow for routine measurements of cardiac output and blood volumes in pediatric patients. The purpose of this study was to validate cardiac output measured by the COstatus system with those obtained by the clinical standard technique of pulmonary artery thermodilution. This was a prospective evaluation performed at a single institution. Any child with a structurally normal heart undergoing hemodynamic evaluation in the cardiac catheterization laboratory was included. A prograde right heart catheterization was performed, and cardiac output was first determined by using the pulmonary artery thermodilution technique. Thermodilution results were then compared with cardiac output measurements obtained using the COstatus system. The results were analyzed by standard correlation, Bland-Altman, and Critchley and Critchley analyses. Twenty-eight patients were evaluated with a median age of 8 yrs and a median weight of 31 kg. The mean thermodilution cardiac index = 3.18 L/min (± 1.35 L/min), and the mean COstatus system cardiac index = 3.17 L/min (± 1.31 L/min). Standard Pearson correlation tests revealed an excellent correlation coefficient of 0.95 (p < .0001). Bland-Altman analysis revealed good clinical agreement with a mean difference of -0.004 L/min with a precision of 0.8 L/min at 2 SD. A percentage error of 25.4% was noticed in this study, which is less than the clinically acceptable limit. The ultrasound dilution technique of determining cardiac output using the COstatus system provides a less invasive method than the traditional pulmonary artery thermodilution for accurately determining cardiac output in children. This is the first validation of the COstatus system in pediatric patients. Further studies are required to establish its accuracy in pediatric patients with cardiac shunts and other hemodynamically unstable conditions.

Pulmonary arterial thermodilution, femoral arterial thermodilution and bioreactance cardiac output monitoring in a pediatric hemorrhagic hypovolemic shock model

AimBioreactance is a new non-invasive method for cardiac output measurement (NICOM). There are no studies that have analysed the utility of this technique in a pediatric animal model of hemorrhagic shock. MethodsA prospective study was performed using 9 immature Maryland pigs weighing 9 to 12kg was performed. A Swan-Ganz catheter, a PiCCO catheter and 4 dual surface electrodes were placed at the four corners of the anterior thoracic body surface. Shock was induced by withdrawing a blood volume of 30mL/kg, and then after, 30mL/kg of Normal saline was administered. Seven simultaneous measurements of cardiac index (CI) were made by pulmonary artery thermodilution (PATD), Femoral artery thermodilution (FATD), and NICOM before, during, and after hypovolaemia and during and after volume expansion. ResultsThe mean difference (bias) of differences (limits of agreement) between PATD and FATD was 0.84 (−1.87–3.51)L/min/1.77m2, between PATD and NICOM was 1.95 (−1.79–5.69)L/min/1.77m2, and between FATD and NICOM was 1.06 (−1.40–3.52)L/min/1.77m2. A moderate correlation was found between PATD and FATD (r=0.43; P=0.01), but no correlation was found between bioreactance and either PATD or FATD. Hypovolemia and volume expansion produced important significant differences in CI as measured by PATD and FATD, while the changes with bioreactance were small and non significant. ConclusionsPATD and FATD measurements showed similar responses to hypovolemic shock and volume expansion. Bioreactance persistently underestimates the CI and is not significantly altered by either inducing hemorrhagic shock, or later, through volume expansion. Bioreactance is not a suitable method for monitoring the CI in pediatric hemorrhagic shock.

Comparison of Doppler Flow Tei-Indexes With Pulmonary Artery Thermodilution Measurement of Cardiac Output in an Experimental Porcine Model

The objective of our study was to compare Doppler echocardiography imaging with pulmonary artery thermodilution measurement during mechanical ventilation. Total 78 piglets (6 weeks old, average weight 24 kg, under general anesthesia) were divided into 4 groups under different cardiac loading conditions (at rest, with increased left ventricular afterload, with increased right ventricular preload, and with increased afterload of both heart ventricles). At 60 and 120 min the animals were examined by echocardiography and simultaneously pulmonary artery thermodilution was used to measure cardiac output. Tei-indexes data were compared with invasively monitored hemodynamic data and cardiac output values together with calculated vascular resistance indices. A total of 224 parallel measurements were obtained. Correlation was found between values of right Tei-index of myocardial performance and changes in right ventricular preload (p<0.05) and afterload (p<0.01). Significant correlation was also found between left index values and changes of left ventricular preload (p<0.001), afterload (p<0.001), stroke volume (p<0.01), and cardiac output (p<0.01). In conclusion, echocardiographic examination and determination of the global performance selectively for the right and left ventricle can be recommended as a suitable non-invasive supplement to the whole set of methods used for monitoring of circulation and cardiac performance.

Retraction Note: Noninvasive assessment of cardiac output using thoracic electrical bioimpedance in hemodynamically stable and unstable patients after cardiac surgery: a comparison with pulmonary artery thermodilution

Retraction Note: Noninvasive assessment of cardiac output using thoracic electrical bioimpedance in hemodynamically stable and unstable patients after cardiac surgery: a comparison with pulmonary artery thermodilution

Perioperative Intra- and Extravascular Volume in Liver Transplant Recipients

Assessing adequate volemia to avoid fluid overload and pulmonary edema perioperatively in liver transplantation (LT) is a challenge both for the anesthetist and the intensivist. Volumetric preload indices, such as intrathoracic blood volume index (ITBVI), measured by transpulmonary thermodilution, and continuous end-diastolic volume index (EDVI), measured by pulmonary artery thermodilution, were shown to better reflect preload than central venous pressure (CVP) or pulmonary artery occlusion pressure (PAOP). An ITBVI increase soon after the graft reperfusion influenced pulmonary perfusion without an alteration of extravascular lung water index (EVLWI) and without impaired oxygenation. This study was designed to evaluate relationships between CVP, PAOP, ITBVI, EDVI, and stroke volume index (SVI) within 48 hours after LT. We also investigated the relationship between EVLWI and arterial partial pressure of oxygen and inspired oxigen fraction ratio (PaO 2/FiO 2). Methods We enrolled 125 patients (103 men and 22 women) undergoing LT. All patients were monitored with the PiCCO system (Pulsion Medical System) and with advanced pulmonary artery catheter connected to the Vigilance System. Hemodynamic-volumetric data were collected upon intensive care unit admission and every 8 hours up to 48 hours. Univariate and multivariate regression models were fitted to assess associations between SVI and EDVI, ITBVI, and filling pressures after adjusting for the right ventricular ejection fraction (RVEF, categorized as ≤30, 31–40, or >40) and the phase of the observation period. We also assessed associations between PaO 2/FiO 2 and EVLWI. Results SVI was associated with EDVI, ITBVI, and RVEF. The models showing the best fit to the data were those including EDVI and ITBVI. Neither CVP nor PAOP showed correlation with SVI. EVLWI inversely correlated with PaO 2/FiO 2. Conclusions In the first 48 hours after LT, ITBVI and EDVI were associated with SVI assessment, whereas CVP and PAOP were not related. EVLWI significantly inversely correlated with PaO 2/FiO 2.