Non-invasive Cardiac Output Monitoring Device Research Articles

Non-invasive cardiac output monitoring (NICOM) in adult congenital heart disease patients with Fontan palliation

RationaleFontan palliation for single ventricle malformations is an increasingly common reason for heart failure in the adult population. Cardiac output (CO) measurement in Fontan physiology is achieved by invasive cardiac catheterization (RHC). Noninvasive CO monitors using thoracic bioreactance (NICOM) have been validated in non-congenital patients but have not been studied in adult Fontan patients. ObjectiveTo compare RHC obtained values of CO using the Fick equation with those measured simultaneously by NICOM in a cohort of adults with Fontan palliation. Methods and resultsIn nineteen patients undergoing routine outpatient RHC, we compared CO values as determined by Fick with those generated by the Starling SV NICOM device. Bland-Altman plots and intraclass correlation coefficients (ICCs) revealed internal consistency within NICOM measurements, however the agreement between RHC and NICOM for CO was poor (ICCs ​∼ ​0.40). We performed sub-analyses using two-sample T-tests and ICCs to determine if clinical cyanosis, acute desaturation, or Fontan pressure affected the difference observed between RHC and NICOM. Neither chronic hypoxia, acute desaturation, nor Fontan pressure measures were found to be associated with the observed difference between the RHC and NICOM measured CO. Discussion and conclusionOur study did not find a correlation between RHC and NICOM derived measures of CO in a cohort of Fontan patients, even in sub-analyses of confounders of Fontan physiology. We observed internal consistency within the device, which may open a role for monitoring of trends rather than absolute values in Fontan patients. Our study was limited due to small sample size.

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Doppler-guided goal-directed fluid therapy does not affect intestinal cell damage but increases global gastrointestinal perfusion in colorectal surgery: a randomized controlled trial. Reisinger KW, Willigers HM, Jansen J, Buurman WA, Von Meyenfeldt MF, Beets GL, Poeze M1. Goal-directed fluid therapy (GDFT) is one of the central components of enhanced recovery after surgery (ERAS) programs. Early studies found a significant reduction in length of stay and also decreased morbidity and mortality associated with the use of GDFT in the setting of traditional care pathways. However, more recent trials have shown no significant benefit, particularly when an ERAS program is fully implemented, reflecting the difficulty in estimating the contribution of each specific component of the bundle of interventions. Moreover, there is also great controversy over the value that the different methodologies used for GDFT, such as Doppler, hemodynamic parameters from an arterial line or noninvasive cardiac output monitoring devices, can provide. In this issue, Reisinger et al. have performed a randomized controlled trial (RCT) with the aim of investigating the effect of Doppler guided GDFT on intestinal damage and gastrointestinal perfusion during colorectal surgery as compared with standard post-operative fluid replacement. It is important to emphasize that unlike previous studies, the authors do not only analyse clinical outcomes but also try to uncover the mechanisms responsible for these results. This RCT shows that Doppler guided GDFT during and after surgery for colorectal cancer increases global gastrointestinal perfusion but no differences were observed in length of stay or postoperative complications. The authors hypothesize that the benefits of fluid optimization might be clinically evident only in high-risk patients. Although the observed changes in gastrointestinal perfusion did not translate into lower morbidity, we must highlight the need for studies such as this in which not only clinical outcomes are investigated but also the mechanisms responsible for them. That is the only way to advance in the knowledge of surgery and provide better care to our patients.

Prediction of fluid responsiveness using a non-invasive cardiac output monitor in children undergoing cardiac surgery

This study evaluated the ability of a non-invasive cardiac output monitoring device (NICOM) to predict fluid responsiveness in paediatric patients undergoing cardiac surgery. Children aged <5 yr undergoing congenital heart surgery were included. Once the sternum had been closed after repair of the congenital heart defect, 10 ml kg(-1) colloid solution was administered for volume expansion. Transoesophageal echocardiography (TOE) was performed to measure stroke volume (SV) and respiratory variation in aortic blood flow peak velocity (ΔV(peak)) before and after volume expansion. Haemodynamic and NICOM variables, including SV(NICOM), stroke volume variance (SVV(NICOM)), cardiac index (CI(NICOM)), and percentage change in thoracic fluid content compared with baseline (TFCd0%), were also recorded. Patients in whom the stroke volume index (SVI), measured using TOE, increased by >15% were defined as fluid responders. Twenty-nine patients were included (13 responders and 16 non-responders). Before volume expansion, only ΔV(peak) differed between groups (P=0.036). The SVV(NICOM), HR, and central venous pressure did not predict fluid responsiveness, but ΔV(peak) did. The CI(NICOM) was not correlated with CI(TOE) (r=0.107, P=0.43). Using Bland-Altman analysis, the mean bias between CI(TOE) and CI(NICOM) was 0.89 litre min(-1) m(-2), with a precision of 1.14 litre min(-1) m(-2). Trending ability of NICOM for SVI and CI was poor when TOE was a reference method. The SVV(NICOM) did not predict fluid responsiveness in paediatric patients during cardiac surgery. In addition, there was no correlation between CI(TOE) and CI(NICOM). Fluid management guided by NICOM should be performed carefully. ClinicalTrials.gov NCT01996956.

Goal-Directed fluid therapy with closed-loop assistance during moderate risk surgery using noninvasive cardiac output monitoring: A pilot study

Goal directed fluid therapy (GDFT) has been shown to improve outcomes in moderate to high-risk surgery. However, most of the present GDFT protocols based on cardiac output optimization use invasive devices and the protocols may require significant practitioner attention and intervention to apply them accurately. The aim of this prospective pilot study was to evaluate the clinical feasibility of GDFT using a closed-loop fluid administration system with a non-invasive cardiac output monitoring device (Nexfin™, BMEYE, Amsterdam, Netherlands). Patients scheduled for elective moderate risk surgery under general anaesthesia were enrolled. The primary anaesthesia team managing the case selected GDFT targets using the controller interface and all patients received a baseline 3 ml kg(-1) h(-1) crystalloid infusion. Colloid solutions were delivered by the closed-loop system for intravascular volume expansion using data from the Nexfin™ monitor. Compliance with GDFT management was defined as acceptable when a patient spent more than 85% of the surgery time in a preload independent state (defined as pulse pressure variation <13%) or when average cardiac index during surgery was >2.5 litre min(-1) m(-2). A total of 13 patients were included in the study group. All patients met the established criteria for delivery of GDFT for greater than 85% of case time. The median length of stay in the hospital was 5 [3-6] days. In this pilot study, GDFT management using the closed-loop fluid administration system with a non-invasive CO monitoring device was feasible and maintained a high rate of protocol compliance. NCT02020863.

Non-invasive hemodynamic monitoring in trauma patients.

BackgroundThe assessment of hemodynamic status is a crucial task in the initial evaluation of trauma patients. However, blood pressure and heart rate are often misleading, as multiple variables may impact these conventional parameters. More reliable methods such as pulmonary artery thermodilution for cardiac output measuring would be necessary, but its applicability in the Emergency Department is questionable due to their invasive nature. Non-invasive cardiac output monitoring devices may be a feasible alternative.MethodsA systematic literature review was conducted. Only studies that explicitly investigated non-invasive hemodynamic monitoring devices in trauma patients were considered.ResultsA total of 7 studies were identified as suitable and were included into this review. These studies evaluated in a total of 1,197 trauma patients the accuracy of non-invasive hemodynamic monitoring devices by comparing measurements to pulmonary artery thermodilution, which is the gold standard for cardiac output measuring. The correlation coefficients r between the two methods ranged from 0.79 to 0.92. Bias and precision analysis ranged from -0.02 +/- 0.78 l/min/m2 to -0.14 +/- 0.73 l/min/m2. Additionally, data on practicality, limitations and clinical impact of the devices were collected.ConclusionThe accuracy of non-invasive cardiac output monitoring devices in trauma patients is broadly satisfactory. As the devices can be applied very early in the shock room or even preclinically, hemodynamic shock may be recognized much earlier and therapeutic interventions could be applied more rapidly and more adequately. The devices can be used in the daily routine of a busy ED, as they are non-invasive and easy to master.

Exploring haemodynamics of haemodialysis using extrema points analysis model

BackgroundHaemodialysis is a form of renal replacement therapy used to treat patients with end stage renal failure. It is becoming more appreciated that haemodialysis patients exhibit higher rates of multiple end organ damage compared to the general population. There is also a strong emerging evidence that haemodialysis itself causes circulatory stress. We aimed at examining haemodynamic patterns during haemodialysis using a new model and test that model against a normal control.MethodsWe hypothesised that blood pressures generated by each heart beat constantly vary between local peaks and troughs (local extrema), the frequency and amplitude of which is regulated to maintain optimal organ perfusion. We also hypothesised that such model could reveal multiple haemodynamic aberrations during HD. Using a non-invasive cardiac output monitoring device (Finometer®) we compared various haemodynamic parameters using the above model between a haemodialysis patient during a dialysis session and an exercised normal control after comparison at rest.ResultsMeasurements yielded 29,751 data points for each haemodynamic parameter. Extrema points frequency of mean arterial blood pressure was higher in the HD subject compared to the normal control (0.761Hz IQR 0.5-0.818 vs 0.468Hz IQR 0.223-0.872, P < 0.0001). Similarly, extrema points frequency of systolic blood pressure was significantly higher in haemodialysis compared to normal. In contrary, the frequency of extrema points for TPR was higher in the normal control compared to HD (0.947 IQR 0.520-1.512 vs 0.845 IQR 0.730-1.569, P < 0.0001) with significantly higher amplitudes.ConclusionHaemodialysis patients potentially exhibit an aberrant haemodynamic behaviour characterised by higher extrema frequencies of mean arterial blood pressure and lower extrema frequencies of total peripheral resistance. This, in theory, could lead to higher variation in organ perfusion and may be detrimental to vulnerable vascular beds.

Noninvasive Cardiac Output Monitoring in Paediatric Cardiac Surgery: Correlation between Change in Thoracic Fluid Content and Change in Patient Body Weight

Change in thoracic fluid content (TFC) derived via a bioreactance technique with a noninvasive cardiac output monitoring device (NICOM) reportedly shows a good correlation with the amount of fluid removed. The present study prospectively evaluated the utility and clinical application of TFC in the intraoperative fluid management of paediatric patients with congenital heart disease, undergoing cardiac surgery with bioreactance-based noninvasive monitoring. Haemodynamic parameters, patient body weight and parameters derived from the NICOM device (including cardiac output, cardiac index, TFC, percentage change in TFC compared with baseline [TFCd0%] and stroke volume variation) were recorded after anaesthesia induction but before surgical incision, and just before departure from the operating room to the intensive care unit. In the 80 paediatric patients included in this study, linear regression analyses demonstrated good correlations between body weight gain and TFCd0%, between body weight gain % and TFCd0%, and between intra operative fluid balance and TFCd0%. TFCd0% may be a useful indicator for intraoperative fluid management in paediatric patients with congenital heart disease, undergoing cardiac surgery.

Ability of a new non-invasive cardiac output monitoring device (Nexfin) to detect hemodynamic changes induced by passive leg raising in spontaneously breathing subjects

Ability of a new non-invasive cardiac output monitoring device (Nexfin) to detect hemodynamic changes induced by passive leg raising in spontaneously breathing subjects

Fluid responsiveness predicted by noninvasive Bioreactance-based passive leg raise test

To study the feasibility of predicting fluid responsiveness (FR) by passive leg raising (PLR) using a Bioreactance-based noninvasive cardiac output monitoring device (NICOM). This prospective, two-center study included 75 consecutive intensive care unit (ICU) adult patients immediately after cardiac surgery. NICOM was used to continuously record cardiac output (CO) at baseline, during a PLR, and then during a 500 ml i.v. rapid colloid infusion. We estimated the precision of NICOM at baseline to derive the least minimum significant change (LMSC) in CO. We studied the predictability of PLR for FR by systematic analysis of different categorizations of PLR and FR, based on percentage change in CO (from 0 to 20%). The LMSC was 8.85%. CO was 4.17 ± 1.04 L min⁻¹ at baseline, 4.38 ± 1.14 L min⁻¹ during PLR, 4.16 ± 1.08 L min⁻¹ upon return to baseline, and 4.85 ± 1.41 L min⁻¹ after fluid infusion. The change in CO following fluid bolus was highly correlated with the change in CO following PLR: y = 0.91x + 4.3, r = 0.77. The Pearson correlation coefficient showed that the best pair of thresholds was found for PLR ≥ 0% predicting FR ≥ 0%. Using this pair of thresholds, PLR had 88% sensitivity and 100% specificity for predicting FR. When we restricted the analysis to change in CO > LMSC, the best pair of thresholds was obtained for PLR > 9% predicting FR > 9%. Using this pair of thresholds, PLR sensitivity was reduced to 68% and specificity to 95%. In this specific population of patients, it is clinically valid to use the bioreactance-based NICOM system to predict FR from changes in CO during PLR.

Introduction of new monitors into clinical anesthesia

There are an increasing number of monitors being developed to measure physiological parameters during the perioperative period. This review provides an overview of some of these new monitors developed for use in clinical anesthesia and outlines the potential advantages of each device. Pitfalls concerning the introduction of additional monitoring devices and the research gaps for introducing these monitors into clinical practice are discussed. Many novel monitoring technologies have been developed, with invasive and noninvasive cardiac output monitoring devices and advanced display technologies being especially prominent. Most of the published literature focuses on monitor efficacy, whereas issues of technology integration and acceptability are given less emphasis. Research on novel display technologies is not integrated with the monitor development, nor is the display of new information considered during the development of new monitors. More research is needed on how to integrate the newly developed monitors into the clinical context to assist information-overloaded anesthesiologists. This is essential to achieve the potential benefit of new monitoring devices.

Comparison of electrical velocimetry and transpulmonary thermodilution for measuring cardiac output in piglets

Monitoring of cardiovascular function is essential during major pediatric and pediatric cardiac surgery. Invasive monitoring of cardiac output (CO) and oxygen delivery is expensive and sometimes associated with adverse events. Therefore, we investigated the accuracy of a new noninvasive CO monitoring device using electrical velocimetry (EV) in comparison with the more invasive transpulmonary thermodilution (TPTD) method. In five fasted, anesthetized and mechanically ventilated piglets, CO was measured simultaneously using EV and TPTD under normal conditions, volume loading, inotropic support and exsanguination. In five piglets, 169 measurements could be performed. The correlations between EV-CO and TPTD-CO were significant for absolute values (P < 0.0001, r = 0.82) and relative changes from baseline (P < 0.0001, r = 0.93). The receiver operating characteristic (ROC) curve analysis of the relative changes of the EV-CO values in relation to the first EV-CO measurement showed a sensitivity of 91% and specificity of 94% (AUC 0.974, 95% CI 0.96-0.99). Changes in TPTD-CO greater than 15% lead to a change of EV-CO in the same direction in 93%. Bland-Altman analysis showed a mean difference between the two methods of -0.63 l x min(-1) with an sd of 0.64 l x min(-1). The lower and upper limits of agreement were -1.88 and 0.62 l x min(-1), percentage limit of agreement was +/-82.8%. The results show that EV is a safe, simple, noninvasive and cost-effective method for continuous trend monitoring of CO in piglets. The agreement of the EV-CO with TPTD-CO is not good enough to replace the standard method in our animal model. A correction factor for body habitus in piglets may be beneficial.