Correlation of Electric Cardiometry and Continuous Thermodilution Cardiac Output Monitoring Systems

Purpose: Impedance Cardiography (ICG) with its drawbacks to reliably estimate cardiac output (CO) when compared to reference methods has led to the development of a novel technique called Electrical Cardiometry (EC). The purpose of this study was to compare EC-CO with the Continuous CO (CCO) derived from Pulmonary Artery Catheter (PAC). Methods: 60 patients scheduled to undergo coronary artery surgery necessitating the placement of PAC were studied in the operating room. Standard ECG electrodes were used for EC-CO measurements. Simultaneous CO measurement from EC and PAC was done at three predefined time points and were correlated. Results: A significant high correlation was found between the EC-CO and CCO at the three time points. Bland and Altman analysis revealed a bias of 0.08 L/min, a precision of 0.15 L/min, with a narrow limit of agreement (-0.13 to 0.28 L/min). The percentage error between the methods was 3.59%. Conclusion: The agreement between EC-CO and CCO is clinically acceptable and these two techniques can be used interchangeably. Mediastinal opening has no effect on the correlation between these two modalities.

Comparison of Cardiac Output Measurement by Noninvasive Method with Electrical Cardiometry and Invasive Method with Thermodilution Technique in Patients Undergoing Coronary Artery Bypass Grafting

Objective: This study was conducted to compare the cardiac output by using Electrical Cardiometry (EC), a noninvasive method of continuous cardiac output monitoring during cardiac surgery with pulmonary artery catheter (PAC) derived cardiac output. Design: Prospective observational clinical study. Setting: Cardiac surgery operating room of a tertiary care cardiac center. Participants: Twenty five patients undergoing coronary artery bypass surgery with cardiopulmonary bypass. Measurements and Main Results: A total of 150 double data of cardiac output were compared with Thermodilution Cardiac Output (TDCO) and Thoracic Electrical Bioimpedance (TEBCO). The TDCO value ranges from 1.8-6.9 litre·min-1 with a mean of 4.39 ± 1.16 litre·min-1 and TEBCO ranges from 1.8-7.1 litre·min-1 with a mean of 4.21 ± 1.16 litre·min-1. The averaged Bland-Altman analysis for TDCO and TEBCO revealed that a mean bias was 0.18 and limit of agreement was -1.25 - 0.89 litre·min-1 and the percentage error (PE) ranged from 22%-32%. The precision for the TDCO was measured to be ±16.2% and the precision for TEBCO was ±19.6%. Receiver Operating Characteristic (ROC) curve analysis between TDCO and TEBCO with a cutoff of 15% shows a sensitivity of 84% and specificity of 63 and area under ROC curve of 0.80. Mountain plot between TDCO and TEBCO shows that a median percentile is 0.25 and value of 97.5 percentile is 1.525. Conclusions: The present study indicates that the electric cardiometry device yields numerically comparable results to cardiac outputs derived from the PAC during the cardiac surgery. Therefore, electrical cardiometry can be used to evaluate haemodynamic variables with clinically acceptable accuracy, when invasive methods are to be avoided or not available.

Continuous versus bolus cardiac output monitoring during orthotopic liver transplantation

BACKGROUND: Cardiac output monitoring is important for critical patients. This study aimed to determine the delayed response of continuous cardiac output (CCO) thermodilution measurement, whether CCO and bolus cardiac output (BCO) thermodilution agree sufficiently to be used interchangeably, and whether CCO monitoring is reliable for patients undergoing liver transplantation. METHODS: Thirteen patients undergoing liver transplantation without veno-venous bypass were studied (37-66 years old, weight 46-75 kg). Continuous and bolus thermodilution measurements were performed at predefined time points using an 'Opti-Q' SvO(2)/CCO monitor (Abbott Laboratories, North Chicago, IL, USA). Bias and 95% limits of agreement were calculated according to Bland and Altman analysis. The limits of agreement by which two methods are judged to be interchangeable were defined in advance as +/-(13%X BCO(mean)) L/min. The repeatability and relative error of CCO, and the differences between CCO and the mean of the two measurements were calculated. RESULTS: Cardiac output measurements yielded 196 data pairs with ranges of 1.9 to 17.9 L/min for CCO and 2.1 to 18.3 L/min for BCO. The response time of CCO was delayed in the early phases after caval clamping and after reperfusion. At most of the measurement points, bias and 95% limits of agreement were -0.18 +/- 1.91 L/min. 95% limits of agreement did not fall within the predetermined limits of agreement of +/- 1.14 L/min. The repeatability coefficient of CCO was 0.36 L/min and the relative error was 4.6 +/- 4.7%. The mean difference between CCO and the average of the two methods was -0.09 L/min (0.49 L/min). CONCLUSIONS: In patients undergoing liver transplantation, the delayed response of CCO limits its application during the early phases after caval clamping and after reperfusion of the graft. The two methods are not interchangeable even in hemodynamic stability. Continuous thermodilution monitoring, however, is reliable or acceptable for clinical purposes.

Hemodynamic monitoring in cardiogenic shock

Cardiogenic shock(CS)is a life-threatening condition characterized by acute end-organ hypoperfusion due to inadequate cardiac output that can result in multiorgan failure,which may lead to death.The diminished cardiac output in CS leads to systemic hypoperfusion and maladaptive cycles of ischemia,inflammation,vasoconstriction,and volume overload.Obviously,the optimal management of CS needs to be readjusted in view of the predominant dysfunction,which may be guided by hemodynamic monitoring.Hemodynamic monitoring enables(1)characterization of the type of cardiac dysfunction and the degree of its severity,(2)very early detection of associated vasoplegia,(3)detection and monitoring of organ dysfunction and tissue oxygenation,and(4)guidance of the introduction and optimization of inotropes and vasopressors as well as the timing of mechanical support.It is now well documented that early recognition,classification,and precise phenotyping via early hemodynamic monitoring(e.g.,echocardiography,invasive arterial pressure,and the evaluation of organ dysfunction and parameters derived from central venous catheterization)improve patient outcomes.In more severe disease,advanced hemodynamic monitoring with pulmonary artery catheterization and the use of transpulmonary thermodilution devices is useful to facilitate the right timing of the indication,weaning from mechanical cardiac support,and guidance on inotropic treatments,thus helping to reduce mortality.In this review,we detail the different parameters relevant to each monitoring approach and the way they can be used to support optimal management of these patients.

How to integrate hemodynamic variables during resuscitation of septic shock?

Resuscitation of septic shock is a complex issue because the cardiovascular disturbances that characterize septic shock vary from one patient to another and can also change over time in the same patient. Therefore, different therapies (fluids, vasopressors, and inotropes) should be individually and carefully adapted to provide personalized and adequate treatment. Implementation of this scenario requires the collection and collation of all feasible information, including multiple hemodynamic variables. In this review article, we propose a logical stepwise approach to integrate relevant hemodynamic variables and provide the most appropriate treatment for septic shock.

Assessment effect of central venous pressure in fluid resuscitation in the patients with shock： a multi-center retrospective research

Background Central venous pressure （CVP） and intrathoracic blood volume index （ITBVI） were used to assess the fluid status. It has previously been shown that CVP is not as accurate as ITBVI for all the shock patients. We therefore hypothesized that the change of CVP has the ability to predict fluid responsiveness in some clinical cases of shock. Methods From September 1st 2009 to September 1st 2011, sixty-three patients with shock from different Intensive Care Unit （ICU） were collected into this retrospective study. All the patients received fluid challenge strategy （infusing 300 ml hydroxyethyl starch in 20 minutes）, were monitored with CVP and pulse-indicated continuous cardiac output （PICCO）. The correlation between changes in cardiac index （ACI）, CVP （ACVP） and ITBVI （AITBVI） were analyzed. Fluid responsiveness was defined as an increase in CI 〉10%. Receiver operating characteristic （ROC） curves were generated for ACVP and AITBVI. Results For all the patients, there was no correlation between ACI and ACVP （P=0.073）, but in the subgroup analysis, the correlation between ACI and ACVP was significant in those younger than 60 years old （P=0.018） and those with hypovolemic shock （P=0.001）. The difference of areas under the ROC curves of ACVP and AITBVI were not statistically significant in the group younger than 60 years old or hypovolemic shock group （P 〉0.05, respectively）. However, no similar results can be found in the group older than 60 years old and the other two shock type groups from ROC curves of ACVP and AITBVI. Conclusions ACVP is not suitable for evaluating the volume status of the shock patients with fluid resuscitation regardless of their condition. However, in some ways, ACVP have the ability to predict fluid responsiveness in the younger shock patients or in the hypovolemic shock patients.

Monitoring extravascular lung water in acute respiratory distress syndrome induced by probable 2009 pandemic influenza A （H1N1） virus： report of two cases

During the spring of 2009, a pandemic novel influenza A （H1NI） virus emerged and spread globally. As of January 3, 2009, more than 208 countries and overseas territories or communities have reported laboratoryconfirmed cases of pandemic influenza H1N1 2009, including at least 12 799 death cases.1 Critical cases developed severe acute respiratory distress syndrome （ARDS） rapidly, which was refractory to conventional mechanical ventilation and rescue therapies.