Non-Invasive Cardiac Output Determination by Two-Dimensional Independent Doppler During and After Cardiac Surgery

doi:10.1016/j.athoracsur.2004.12.034

The Annals of Thoracic Surgery

Volume 80, Issue 4, October 2005, Pages 1479-1483

https://doi.org/10.1016/j.athoracsur.2004.12.034 Get rights and content

Purpose

This study was to compare noninvasive measurement of cardiac output (CO) using a novel Doppler technique with invasive CO measurements in the postcardiac surgical intensive care unit.

Description

Thirty-six patients (67.2 ± 10 years, New York Heart Association functional class 3.1 ± 0.3) undergoing coronary revascularization were prospectively examined postoperatively. One hundred eighty paired CO and stroke volume measurements were compared from the noninvasive USCOM device (Sydney, Australia) and the invasive Swan-Ganz catheter at varying COs. Eighteen measurements were performed intraoperatively by direct insonation of the right ventricular outflow tract.

Evaluation

Mean noninvasive and invasive CO values were 5.15 ± 1.98 L/min and 4.92 ± 2.0 L/min, respectively (r = 0.870; p < 0.01). The mean difference between methods was −0.23 ± 1.01 L/min greater than a range of CO values from 2.5 to 9.9 L/min. Mean central venous saturation percentage was 72 ± 9%, correlating with both noninvasive and invasive CO (r = 0.474 and 0.606, respectively, p < 0.01). Intraoperatively, both direct and invasive CO were identical.

Conclusions

Using the ultrasonic cardiac output monitoring (USCOM) device it is possible to determine noninvasive beat-to-beat CO in postcardiac surgery patients without the possible complications associated with invasive right heart catheterization. The USCOM CO and stroke volume showed a very good agreement with invasive Swan-Ganz measures and correlated with central venous saturation percentage.

Section snippets

Technology

After written consent, we prospectively studied 36 consecutive patients (26 males; mean age 67.2 ± 10 years; height 170 ± 8 cm; weight 79 ± 14 kg; New York Heart Association functional class 3.1 ± 0.3) undergoing surgical coronary revascularization, with a preoperative electrocardiogram demonstrating sinus rhythm without any higher grade supraventricular or ventricular arrhythmia.

The USCOM system is based on a 300 MHz National Semiconductor GEODE GX1 CPU with 64 MB SDRAM based on Microsoft

Technique

Intraoperatively 6 patients were studied after median sternotomy and revascularization, with CO simultaneously determined by PAC and the USCOM system with the transducer placed directly on the pulmonary artery after cessation of extracorporeal circulation. Postoperatively, all patients were monitored invasively with the PAC using the Baxter thermodilution system (Baxter Healthcare Corp, Irvine, CA), with simultaneous CO, stroke volume (SV), and central venous saturations (CVS) percentage

Hemodynamic Data

The mean heart rate was 103 ± 11 bpm, and the mean invasive systolic and diastolic blood pressures were 121 ± 21 mm Hg and 62 ± 13 mm Hg, respectively. Mean right atrial pressure was 9 ± 3 mm Hg, direct left atrial pressure was 13 ± 5 mm Hg, and CVS percentage was 72 ± 9%.

Invasive and Noninvasive Cardiac Output Data

Invasive CO measured by the PAC was 4.92 ± 2 L/min (95% confidence intervals, 4.63 to 5.22 L/min). The noninvasive Doppler device determined CO by the USCOM system was 5.15 ± 1.98 L/min (95% confidence intervals, 4.86 to 5.44

Comment

This study confirmed that it is feasible, using the transcutaneous USCOM device, to determine beat-to-beat CO in critically ill patients in the postcardiac surgical intensive care noninvasively. Measurements demonstrated a high correlation to invasively determined CO with a PAC as both correlated well with SV and CVS percentage. These findings confirm the reliability of the USCOM device and suggest that it may have multiple clinical applications in which the immediate and noninvasive assessment

Disclosures and Freedom of Investigation

The authors independently determined the design, method, outcome, data analysis, and writing of this article without influence from any external party.

Disclaimer

The Society of Thoracic Surgeons, the Southern Thoracic Surgical Association, and The Annals of Thoracic Surgery neither endorse nor discourage use of the new technology described in this article.

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Cited by (65)

Validation of capnodynamic determination of cardiac output by measuring effective pulmonary blood flow: a study in anaesthetised children and piglets
2018, British Journal of Anaesthesia
Citation Excerpt :
In the absence of major cardiac or pulmonary shunting, COEPBF will be closely related to pulmonary blood flow and thus systemic CO.15 Haemoglobin, which is required for calculating COEPBF, was measured using a HemoCue® Hb 201+ (Hemoque AB, Angelholm, Sweden). COSSD has been evaluated for adult and paediatric patients by comparing it with a variety of reference methods16,17 and has been used extensively in various clinical settings.18,19 COSSD was measured in every patient by a single, highly experienced sonographer (P.W.) using the supra-sternal Doppler measurement technique.
Effective pulmonary blood flow (CO_EPBF) has recently been validated as a technique for determining cardiac output (CO) in animals of varying sizes. The primary aim of our study was to investigate this new technique in paediatric surgical patients, compared with suprasternal two-dimensional Doppler (CO_SSD).
A total of 15 children undergoing cleft lip/palate surgery were investigated. Before the start of surgery, manoeuvres that were anticipated to reduce (increase in PEEP from 3 to 10 cm H₂O) and increase (atropine) CO were undertaken. A study in mechanically ventilated piglets was also undertaken under general anaesthesia, measuring CO_EPBF and pulmonary artery (CO_TS) flow by ultrasonic probe as the comparator. Bias (Bland−Altman plots) and limits of agreement were assessed for effective pulmonary blood flow and CO_SSD or CO_TS.
In paediatric patients (median age 8.5 months), overall bias was −8.1 (limits of agreement −82 to +66) ml kg⁻¹ min⁻¹, with a mean percentage error of 48% and a concordance rate of 64%. In the piglet model, overall bias was −1 (−36 to +38) ml kg⁻¹ min⁻¹, with a mean percentage error of 31% and a concordance rate of 95%.
Under controlled experimental conditions, CO_EPBF is associated with excellent agreement and good trending ability when compared with the gold standard CO_TS. In the paediatric clinical setting, CO_EPBF performs well; by contrast, CO_SSD, an operator- and anatomy-dependent technology, appears less reliable than CO_EPBF.
Accuracy and precision of the ultrasound cardiac output monitor (USCOM 1A) in pregnancy: Comparison with three-dimensional transthoracic echocardiography
2014, British Journal of Anaesthesia
Cardiac output (CO) monitoring is helpful in the assessment of critically ill pregnant women, but invasive monitors are often unsuitable for use. We aimed to measure agreement between the non-invasive ultrasound cardiac output monitor (USCOM) and three-dimensional transthoracic echocardiography (3D-TTE) in pregnant women.
Healthy pregnant women from 25 weeks gestation onwards participated. In the left lateral position at rest, CO was measured with the USCOM and 3D-TTE. A single operator performed all USCOM measurements, with a different operator performing all echocardiography. Both were blinded to results from the other device. Each USCOM trace was analysed using two modes: flowtrace (FT) and touchpoint (TP). A second, blinded USCOM reading was taken to assess reproducibility.
USCOM readings were obtained in 92, and 3D-TTE images in 85 participants. The mean CO was 5.7, 7.7, and 6.2 litre min⁻¹ measured by 3D-TTE, USCOM FT, and USCOM TP, respectively. USCOM bias was +2.0 litre min⁻¹ (FT) and +0.4 litre min⁻¹ (TP). Limits of agreement were −0.2 to +4.2 litre min⁻¹ (FT) and −1.4 to +2.3 litre min⁻¹ (TP). The mean percentage difference was 32.6% (FT) and 31.4% (TP) for CO and 27.0% (FT) and 27.5% (TP) for stroke volume. Intraclass correlation between repeated USCOM readings was 0.9 (FT) and 0.86 (TP).
USCOM has acceptable agreement with 3D-TTE for the measurement of CO in pregnancy. The positive bias of the USCOM, particularly in the FT mode, may be due to the hyperdynamic cardiovascular state in pregnancy. We suggest using the TP mode in this patient population.
Is arterial pulse contour analysis using nexfin a new option in the noninvasive measurement of cardiac output? A pilot study
2013, Journal of Cardiothoracic and Vascular Anesthesia
Citation Excerpt :
The latter has become the new noninvasive gold standard for the assessment of cardiac function.11 Several approaches like impedance cardiography,12,13 rebreathing tests,14-16 ultrasound techniques,17,18 and invasive as well as noninvasive PCA had been investigated. In validation studies, systematic differences between the invasive (intra-arterial) and the noninvasive (finger cuff) measurement of pressure could be detected.19,20
A growing interest in monitoring cardiac output (CO) noninvasively has emerged; however, its determination has been difficult using the standard approaches. The aim of this study was to evaluate the accuracy and precision of pulse contour analysis (PCA) compared with cardiac magnetic resonance imaging (CMR).
A single-center prospective study.
A university hospital.
Thirty-nine consecutive stable patients undergoing CMR.
CO was determined twice by PCA using the Nexfin monitoring system (BMEYE BV, Amsterdam, The Netherlands). Measurements were performed after 10 minutes of rest in a stable supine position immediately before or after the CMR examination.
There was a mean bias of 0.2 ± 1.9 L/min between CMR and PCA and a reproducibility of 0.2 ± 0.6 L/min for PCA. Between 4.8 and 6.3 L/min (second quartile of CO_CMR), there was a good agreement (mean bias = −0.2 ± 1.3 L/min). Comparing quartile 1 (−1.3 ± 2.0 L/min) overestimating and quartiles 3 (1.4 ± 0.9 L/min) and 4 (0.9 ± 2.0 L/min) underestimating CO, a statistically significant difference was found. The reproducibility was not affected by the quartile (p = 0.23, analysis of variance), whereas there was a significant difference between the nonoutlier and outlier group when using the Mann-Whitney U test (p = 0.02).
Noninvasive PCA allows the safe and economic measurement of CO, yet it still has major limitations. Although the agreement with CMR was acceptable, there was a clinically unacceptable variation; absolute values should not be used interchangeably. These results suggest that therapeutic interventions and clinical decisions should not be based on noninvasive PCA measurements at the present time.
Clinical practice guide for the management of low cardiac output syndrome in the postoperative period of heart surgery
2012, Medicina Intensiva
El síndrome de bajo gasto cardiaco es una potencial complicación de los pacientes intervenidos de cirugía cardiaca, y asocia un aumento de la morbi-mortalidad. La presente guía pretende proporcionar recomendaciones para el manejo de estos pacientes, en el postoperatorio inmediato, ingresados en UCI. Las recomendaciones se han agrupado en diferentes apartados, tratando de dar respuesta desde los conceptos más básicos como es la definición, a los diferentes apartados de monitorización básica y avanzada y terminando con el complejo manejo de este síndrome. Se propone un algoritmo de manejo inicial, asi como otros de fracaso ventricular predominantemente izquierdo o derecho. La mayor parte de las recomendaciones están basadas en el consenso de expertos, debido a la falta de estudios clínicos aleatorizados, de adecuado diseño y tamaño muestral en este grupo de pacientes. La calidad de la evidencia y la fuerza de las recomendaciones se realizó siguiendo la metodología GRADE. La guía se presenta como una lista de recomendaciones (y nivel de evidencia de cada recomendación) para cada pregunta del tema seleccionado. A continuación, en cada pregunta, se procede a la justificación de las recomendaciones.
The low cardiac output syndrome is a potential complication in cardiac surgery patients and associated with increased morbidity and mortality. This guide is to provide recommendations for the management of these patients, immediately after surgery, admitted to the ICU. The recommendations are grouped into different sections, trying to answer from the most basic concepts such as the definition to the different sections of basic and advanced monitoring and ending with the complex management of this syndrome. We propose an algorithm for initial management, as well as two other for ventricular failure (predominantly left or right). Most of the recommendations are based on expert consensus because of the lack of randomized trials of adequate design and sample size in this group of patients. The quality of evidence and strength of the recommendations were made following the GRADE methodology. The guide is presented as a list of recommendations (and level of evidence for each recommendation) for each question on the selected topic. Then for each question, we proceed to the justification of the recommendations.
Non-invasive hemodynamic monitoring in burn shock resuscitation
2010, Burns
Nurse-determined assessment of cardiac output. Comparing a non-invasive cardiac output device and pulmonary artery catheter: A prospective observational study
2009, International Journal of Nursing Studies
The accurate measurement of Cardiac output (CO) is vital in guiding the treatment of critically ill patients. Invasive or minimally invasive measurement of CO is not without inherent risks to the patient. Skilled Intensive Care Unit (ICU) nursing staff are in an ideal position to assess changes in CO following therapeutic measures. The USCOM (Ultrasonic Cardiac Output Monitor) device is a non-invasive CO monitor whose clinical utility and ease of use requires testing.
To compare cardiac output measurement using a non-invasive ultrasonic device (USCOM) operated by a non-echocardiograhically trained ICU Registered Nurse (RN), with the conventional pulmonary artery catheter (PAC) using both thermodilution and Fick methods.
Prospective observational study.
Between April 2006 and March 2007, we evaluated 30 spontaneously breathing patients requiring PAC for assessment of heart failure and/or pulmonary hypertension at a tertiary level cardiothoracic hospital.
SCOM CO was compared with thermodilution measurements via PAC and CO estimated using a modified Fick equation. This catheter was inserted by a medical officer, and all USCOM measurements by a senior ICU nurse. Mean values, bias and precision, and mean percentage difference between measures were determined to compare methods. The Intra-Class Correlation statistic was also used to assess agreement. The USCOM time to measure was recorded to assess the learning curve for USCOM use performed by an ICU RN and a line of best fit demonstrated to describe the operator learning curve.
In 24 of 30 (80%) patients studied, CO measures were obtained. In 6 of 30 (20%) patients, an adequate USCOM signal was not achieved. The mean difference (±standard deviation) between USCOM and PAC, USCOM and Fick, and Fick and PAC CO were small, −0.34 ± 0.52 L/min, −0.33 ± 0.90 L/min and −0.25 ± 0.63 L/min respectively across a range of outputs from 2.6 L/min to 7.2 L/min. The percent limits of agreement (LOA) for all measures were −34.6% to 17.8% for USCOM and PAC, −49.8% to 34.1% for USCOM and Fick and −36.4% to 23.7% for PAC and Fick. Signal acquisition time reduced on average by 0.6 min per measure to less than 10 min at the end of the study.
In 80% of our cohort, USCOM, PAC and Fick measures of CO all showed clinically acceptable agreement and the learning curve for operation of the non-invasive USCOM device by an ICU RN was found to be satisfactorily short. Further work is required in patients receiving positive pressure ventilation.

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^⁎: The first two authors contributed equally to this work.

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New technologyNon-Invasive Cardiac Output Determination by Two-Dimensional Independent Doppler During and After Cardiac Surgery

Purpose

Description

Evaluation

Conclusions

Section snippets

Technology

Technique

Hemodynamic Data

Invasive and Noninvasive Cardiac Output Data

Comment

Disclosures and Freedom of Investigation

Disclaimer

Chest

The effectiveness of right heart catheterization in the initial care of critically ill patients

JAMA

Pulmonary artery catheter study groupa multicenter study of physicians’ knowledge of the pulmonary artery catheter

JAMA

Recommendations for quantification of Doppler echocardiographya report from the Doppler quantification task force of the nomenclature and standards committee of the American Society of echocardiography

J Am Soc Echocardiogr

A meta-analysis of studies using bias and precision statistics to compare cardiac output measurement techniques

J Clin Monit

New technology
Non-Invasive Cardiac Output Determination by Two-Dimensional Independent Doppler During and After Cardiac Surgery