Cardiac Output Monitoring Devices Research Articles

Cardiogenic shock diagnosis and management in general intensive care: a nationwide survey.

the epidemiology of cardiogenic shock has evolved over the years: in the last decades an increasing prevalence of cardiogenic shock related to acute decompensated heart failure was observed. Therefore, treatment bundles should be updated according to the underlying pathophysiology. No data exist regarding the diagnostic/therapeutic strategies in general intensive care units. A 27-questions survey was spread through the GiViTi (Italian Group for the Evaluation of Interventions in Intensive Care Medicine). The results were then divided according to level of hospitals (1st-2nd versus 3rd). Sixty-nine general intensive care units replied to the survey. The shock team is present in 13% of institutions; Society for Cardiovascular Angiography and Interventions shock classification is applied only in 18.8%. Among the ICUs, 94.2% routinely use a cardiac output monitoring device (pulmonary artery catheter more frequently in 3rd level centers). The first-line adrenergic drug are vasopressors in 27.5%, inotrope in 21.7% or their combination in 50.7%; 79.7% applies fluid challenge. The first vasopressor of choice is norepinephrine (95.7%) (maximum dosage tolerated higher than 0.5 mcg/kg/min in 29%); the first line inotrope is dobutamine (52.2%), followed by epinephrine in 36.2%. The most frequently used mechanical circulatory supports are intra-aortic balloon pump (71%), Impella (34.8%) and VA-ECMO (33.3%); VA-ECMO is the first line strategy in refractory cardiogenic shock (60.8%). According to this survey, there is no standardized approach to cardiogenic shock amongst Italian general intensive care units. The application of shock severity stratification and the treatment bundles may play a key role in improving the outcome.

Determinants of Urine Output Using Advanced Hemodynamic Monitoring in Critically Ill Patients Undergoing Continuous Renal Replacement Therapy

Introduction: Low cardiac output and hypovolemia are candidate macrocirculatory mechanisms explanatory of de novo anuria in intensive care unit (ICU) patients undergoing continuous renal replacement therapy (CRRT). We aimed to determine the hemodynamic parameters and CRRT settings associated with the longitudinal course of UO during CRRT. Methods: This is an ancillary analysis of the PRELOAD CRRT observational, single-center study (NCT03139123). Enrolled adult patients had severe acute kidney injury treated with CRRT for less than 24 h and were monitored with a calibrated continuous cardiac output monitoring device. Hemodynamics (including stroke volume index [SVI] and preload-dependence, identified by continuous cardiac index variation during postural maneuvers), net ultrafiltration (UF_NET), and UO were reported 4-hourly, over 7 days. Two study groups were defined at inclusion: non-anuric participants if the cumulative 24 h UO at inclusion was ≥0.05 mL kg⁻¹ h⁻¹, and anuric otherwise. Quantitative data were reported by its median [interquartile range]. Results: Forty-two patients (age 68 [58–76] years) were enrolled. At inclusion, 32 patients (76%) were not anuric. During follow-up, UO decreased significantly in non-anuric patients, with 25/32 (78%) progressing to anuria within 19 [10–50] hours. Mean arterial pressure (MAP) and UF_NET did not significantly differ between study groups during follow-up, while SVI and preload-dependence were significantly associated with the interaction of study group and time since inclusion. Higher UF_NET flow rates were significantly associated with higher systemic vascular resistances and lower cardiac output during follow-up. Multivariate analyses showed that (1) lower UO was significantly associated with lower SVI, lower MAP, and preload-independence; and (2) higher UF_NET was significantly associated with lower UO. Conclusions: In ICU patients treated with CRRT, those without anuria showed a rapid loss of diuresis after CRRT initiation. Hemodynamic indicators of renal perfusion and effective volemia were the principal determinants of UO during follow-up, in relation with the hemodynamic impact of UF_NET setting.

Vascular Reactivity Index and PELOD-2 as a mortality predictor in paediatric septic shock: a single-centre retrospective study

BackgroundThe mortality rate for children with septic shock is stil quite high in low-income and middle-income countries (31.7%). One of the most widely used scoring systems to assess mortality in...

Fluid balance neutralization secured by hemodynamic monitoring versus protocolized standard of care in critically ill patients requiring continuous renal replacement therapy: study protocol of the GO NEUTRAL randomized controlled trial

BackgroundFluid overload is associated with worse outcome in critically ill patients requiring continuous renal replacement therapy (CRRT). Net ultrafiltration (UFNET) allows precise control of the fluid removal but is frequently ceased due to hemodynamic instability episodes. However, approximately 50% of the hemodynamic instability episodes in ICU patients treated with CRRT are not associated with preload dependence (i.e., are not related to a decrease in cardiac preload), suggesting that volume removal is not responsible for these episodes of hemodynamic impairment. The use of advanced hemodynamic monitoring, comprising continuous cardiac output monitoring to repeatedly assess preload dependency, could allow securing UFNET to allow fluid balance control and prevent fluid overload.MethodsThe GO NEUTRAL trial is a multicenter, open-labeled, randomized, controlled, superiority trial with parallel groups and balanced randomization with a 1:1 ratio. The trial will enroll adult patients with acute circulatory failure treated with vasopressors and severe acute kidney injury requiring CRRT who already have been equipped with a continuous cardiac output monitoring device. After informed consent, patients will be randomized into two groups. The control group will receive protocolized fluid removal with an UFNET rate set to 0–25 ml h−1 between inclusion and H72 of inclusion. The intervention group will be treated with an UFNET rate set on the CRRT of at least 100 ml h−1 between inclusion and H72 of inclusion if hemodynamically tolerated based on a protocolized hemodynamic protocol aiming to adjust UFNET based on cardiac output, arterial lactate concentration, and preload dependence assessment by postural maneuvers, performed regularly during nursing rounds, and in case of a hemodynamic instability episode. The primary outcome of the study will be the cumulative fluid balance between inclusion and H72 of inclusion. Randomization will be generated using random block sizes and stratified based on fluid overload status at inclusion. The main outcome will be analyzed in the modified intention-to-treat population, defined as all alive patients at H72 of inclusion, based on their initial allocation group.DiscussionWe present in the present protocol all study procedures in regard to the achievement of the GO NEUTRAL trial, to prevent biased analysis of trial outcomes and improve the transparency of the trial result report. Enrollment of patients in the GO NEUTRAL trial has started on June 31, 2021, and is ongoing.Trial registrationClinicalTrials.gov NCT04801784. Registered on March 12, 2021, before the start of inclusion.

Calibrated cardiac output monitoring versus standard care for fluid management in the shocked ICU patient: a pilot randomised controlled trial

BackgroundDespite the evidence for calibrated cardiac monitored devices to determine fluid responsiveness, there is minimal evidence that the use of cardiac output monitor devices leads to an overall change in IV fluid use. We sought to investigate the feasibility of performing a randomised controlled study using calibrated cardiac output monitoring devices in shocked ICU patients and whether the use of these devices led to a difference in total volume of IV fluid administered.MethodsWe performed a single-centre non-blinded randomised controlled study which included patients who met the clinical criteria for shock on admission to ICU. Patients were divided into two groups (cardiac output monitors or standard) by block randomisation. Patients allocated to the cardiac output monitor all received EV1000 with Volume View sets. Daily intravenous fluid administration and cumulative fluid balance was recorded for 3 days. The primary outcome assessed was the difference in daily intravenous fluid administration and cumulative fluid balance at 72 h between the two groups. We also assessed how often the clinicians used the cardiac monitor to guide fluid therapy and the different reasoning for initiating further intravenous fluids.ResultsEighty patients were randomised and 37 received calibrated cardiac output monitors. We found no adverse outcomes in the use of calibrated cardiac output monitoring devices and that was feasible to perform a randomised controlled trial. There was no significant difference between the standard care group vs the cardiac monitoring group for cumulative fluid balance (2503 ± 3764 ml vs 2458 ± 3560 ml, p = 0.96). There was no significant difference between the groups for daily intravenous fluid administration on days 1, 2 or 3. In the cardiac monitored group, only 43% of the time was the EV1000 output incorporated into the decision to give further intravenous fluids.ConclusionIt is feasible to perform a randomised controlled trial using calibrated cardiac output monitoring devices. In addition, there was no trend to suggest that the use of a cardiac monitors leads to lower IV fluid use in the shocked patient. Further trials will require study designs to optimise the use of a cardiac output monitor to determine the utility of these devices in the shocked patient.Trial registrationANZCTR, ACTRN12618001373268. Registered 15 August 2018—retrospectively registered.

Cardiac output monitoring: Technology and choice.

The accurate quantification of cardiac output (CO) is given vital importance in modern medical practice, especially in high-risk surgical and critically ill patients. CO monitoring together with perioperative protocols to guide intravenous fluid therapy and inotropic support with the aim of improving CO and oxygen delivery has shown to improve perioperative outcomes in high-risk surgical patients. Understanding of the underlying principles of CO measuring devices helps in knowing the limitations of their use and allows more effective and safer utilization. At present, no single CO monitoring device can meet all the clinical requirements considering the limitations of diverse CO monitoring techniques. The evidence for the minimally invasive CO monitoring is conflicting; however, different CO monitoring devices may be used during the clinical course of patients as an integrated approach based on their invasiveness and the need for additional hemodynamic data. These devices add numerical trend information for anesthesiologists and intensivists to use in determining the most appropriate management of their patients and at present, do not completely prohibit but do increasingly limit the use of the pulmonary artery catheter.

Predictors of effective fluid therapy in the intensive care unit

Objective Static and dynamic indices predicting fluid responsiveness (FR) in critically ill patients, physiological basis, advantages, disadvantages, and cut-off values for each method. Materials and methods Medical textbooks, Medscape, PubMed, and the ScienceDirect. The databases were searched from the start date of the database and a search was performed on May 2016 with no language restriction. The initial search found 25 articles of which 15 met the inclusion criteria that address preload responsiveness, FR, and cardiac output monitoring devices. Extraction was carried out depending on the validity, quality, and originality of the selected reviews and studies; and the focus was on studies that presented the latest updated findings on FR in the ICU. Each review and study was reviewed independently without intercomparisons. The layout was selected to present a big data including the most updated findings on the subject. Result Dynamic indices predicting FR in the ICU provide the best prognosis and outcome. Early detection of fluid nonresponsive patients in the ICU will help avoid fluid overload, which is an independent predictor of mortality. Conclusion Dynamic FR monitoring methods are preferable to static methods. Each dynamic method has its benefits and limitations. Inferior vena cava (IVC) sonography such as IVC collapsibility, IVC distensibillity, and delta IVC might provide a valuable tool and alternate approach for guidance of fluid therapy in spontaneously breathing and mechanically ventilated patients, respectively.

The utilization spectrum of cardiac output monitoring devices among anesthesiology programs across Veterans Health Administration in the United States.

Background:Electronic monitoring of physiologic variables has gained widespread support over the past decade for critical patients in the intensive care setting. Specifically, anesthesiologists have increased the emphasis and practice of hemodynamic control through monitoring cardiac output (CO). However, these physicians are presented with several options in terms of how they wish to study the trend of this physiologic parameter.Materials and Methods:A survey was distributed to 250 general and subspecialty-trained anesthesiologists. A series of questions were presented in terms of preference of patient monitoring methods requiring yes or no answers. Anesthesiologists were asked about subspecialty training, years since residency graduation, and preferences toward specific hemodynamic monitoring tools. Nonparametric statistical analysis and Chi-squared tests were used to analyze both normal and nonnormally distributed data.Results:CO monitoring devices were implemented by 106 out of 133 anesthesiologists, with 98 of these physicians utilizing CO monitoring for fluid and vasopressors response. Of the physicians implementing a monitoring device, 48 out of 107 physicians preferred pulmonary artery catheter, while pulse contour analysis was preferred by 17 anesthesiologists. An echocardiography unit was available to the department for 90 anesthesiologists, and 77 anesthesiologists were trained to use this technology for monitoring cardiac function.Conclusion:Many anesthesiologists have placed emphasis on the importance of CO monitoring within the intensive care setting. However, physicians are still faced with multiple options in terms of how they wish to specifically monitor this hemodynamic variable. Factors that influence such decisions include the time of physician's residency training along with patient and clinical case characteristics.

Noninvasive cardiac output monitoring using bioreactance in pediatric continuous blood purification patients

Objective To study the influence of continuous blood purification(CBP) on cardiac output of pediatric patients using bioreactance. Methods Patients underwent CBP in PICU and nephrology ward from March 2014 were prospectively enrolled after approval by ethics committee.CBP therapies were all performed by Fresenius Medical Care hemodialysis machine.Cardiac output values were obtained using the non-invasive cardiac output monitoring(NICOM) device (Cheetah Medical). Blood pressure, heart rate, cardiac index(CI) and stroke volume index(SVI) were recorded before the therapy, at the beginning of therapy, during the course of therapy, and at the end of each therapy. Results Twenty-one pediatric patients (from 1.0 year to 15.5 years) were recruited and 69 treatments were recorded from March 2014 to December 2016.The basic CI was 3.4 (2.4, 6.1) L/(min·m2), basic SVI was 43 (26, 75) ml/(m2·beat). During the beginning of therapy, mean arterial pressure(MAP), CI and SVI all dropped from the baseline (P<0.001), whereas heart rate increased.During the course of CBP, CI and SVI (were both recorded every 4 hours) kept on dropping and stayed at a relatively lower level.Course CI was 3.0 (2.4, 4.6) L/(min·m2) and course SVI was 28 (21, 57) ml/(m2·beat). At the end of therapy, CI was 3.4 (2.5, 5.3) L/(min·m2), with no significant difference from the baseline CI (P=0.073). However, the SVI at the end of therapy was 35 (25, 67) ml/(m2·beat), higher than the course SVI but still lower than the basic SVI, the differences were statistically significant (P<0.05). Conclusion CI and SVI continue to decline at the beginning of CBP treatment and remain at a lower level throughout the course of treatment.After the therapy, CI has returned to the basic level whereas SVI has not recovered. Key words: Bioreactance; Noninvasive cardiac output monitoring; Continuous blood purification; Children,

Clearsight™ use for haemodynamic monitoring during the third trimester of pregnancy – a validation study

BackgroundWe assessed the validity of Clearsight™ as a non-invasive cardiac output and stroke volume monitoring device, comparing it with transthoracic echocardiography measurements during the third trimester of pregnancy. MethodsMeasurements obtained from Clearsight™ were compared with those from echocardiography as the gold standard. The precision and accuracy of the Clearsight™ was measured using the Bland and Altman method. Clinical agreement with echocardiography was assessed using the agreement tolerability index. ResultsMeasurements were recorded from 44 pregnant women with a median [IQR range] gestational age of 33 [30–37] weeks. We found that Clearsight™ measurements presented a systematic overestimation of cardiac output, with mean bias [CI 95%] of 2.7 [2.3–3.0] L/min, with limits of agreement of −0.1 to 5.4 L/min. It overestimated stroke volume, with a bias of 29.5 [25.0–33.4] mL and a limit of agreement of −1.6 to 60.1 mL. In addition, the analysis of cardiac output showed a percentage of error of 41% and intra-class correlation [CI 95%] of 0.37 [0.17 to 0.53, P <0.001]. For stroke volume, the percentage of error was 40% and intra-class correlation 0.16 [−0.1 to 0.34; P=0.27]. We found that agreement tolerability index scores were unacceptable. We evaluated the ability of the device to track changes in cardiac output by inducing a left lateral decubitus position, but the analysis was inconclusive. ConclusionThe agreement between Clearsight™ and the echocardiography measurements of cardiac output and stroke volume were not within an acceptable range in the third trimester of pregnancy.

The Correlation between the Change in Thoracic Fluid Content and the Change in Patient Body Weight in Fontan Procedure.

Background The thoracic fluid content (TFC) and its percent change compared to the baseline (TFCd0%) derived from a bioreactance technique using a noninvasive cardiac output monitoring (NICOM) device correlate well with the amount of fluid removal in patients undergoing hemodialysis and with intraoperative fluid balance in pediatric patients undergoing cardiac surgery. We hypothesized that TFC or TFCd0% would also be a useful indicator allowing fluid management in pediatric patients undergoing a Fontan procedure. Methods The medical records of patients who underwent an elective Fontan procedure were reviewed retrospectively. The intraoperative variables recorded at two time points were used in the analysis: when the NICOM data obtained just after anesthesia induction (T0) and just before transfer of the patient from the operating room to the ICU (T1). The analyzed variables were hemodynamic parameters, TFC, TFCd0%, stroke volume variation, body weight gain, change in the central venous pressure, and difference in the TFC (ΔTFC). Results The correlation coefficient between TFCd0% and body weight gain was 0.546 (p = 0.01); between TFCd0% and body weight gain% 0.572 (p = 0.007); and between TFCd0% and intraoperative fluid balance 0.554 (p = 0.009). The coefficient of determination derived from a linear regression analysis of TFCd0% versus body weight gain was 0.30 (p = 0.01); between TFCd0% and body weight gain% 0.33 (p = 0.007); and between TFCd0% and intraoperative fluid balance 0.31 (p = 0.009). Conclusions TFCd0% correlated well with body weight gain, body weight gain%, and intraoperative fluid balance. It is a useful indicator in the intraoperative fluid management of pediatric patients undergoing a Fontan procedure. Trial Registration This trial is registered with Clinical Research Information Service KCT0002062.

Editor's Choice

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.

Perioperative Cardiac Output Monitoring Utilizing Non-pulse Contour Methods

The purpose of this review was to provide an overview of the recent concepts regarding cardiac output measurement devices that utilize non-pulse contour methods, especially in an intraoperative setting. The techniques include inert gas rebreathing method, partial CO2 rebreathing method, impedance cardiography, and its derivative technologies such as electrical velocimetry and bioreactance, transesophageal echocardiography/Doppler, and transthoracic echocardiography/Doppler. We focused on the invasiveness of the devices and their underlying technology. Although various types of cardiac output monitoring devices are available, none of them may be considered as an ideal device in terms of accuracy, trending ability of cardiac output changes, and reproducibility of measurements. There are increasing types of devices applicable for intraoperative use, yet only few data are available regarding the trending ability of cardiac output changes and reproducibility of the measurements. Therefore, the empirical application of these devices for various surgical patients may be done under the consideration of their invasiveness and their underlying technology, and it may provide us with more data over time. The non-pulse contour-derived cardiac output measurement devices are classified according to their underlying principles, which closely reflect their advantages and disadvantages in the perioperative setting.

Minimally invasive cardiac output technologies in the ICU: putting it all together.

Haemodynamic monitoring is a cornerstone in the diagnosis and evaluation of treatment in critically ill patients in circulatory distress. The interest in using minimally invasive cardiac output monitors is growing. The purpose of this review is to discuss the currently available devices to provide an overview of their validation studies in order to answer the question whether these devices are ready for implementation in clinical practice. Current evidence shows that minimally invasive cardiac output monitoring devices are not yet interchangeable with (trans)pulmonary thermodilution in measuring cardiac output. However, validation studies are generally single centre, are based on small sample sizes in heterogeneous groups, and differ in the statistical methods used. Minimally and noninvasive monitoring devices may not be sufficiently accurate to replace (trans)pulmonary thermodilution in estimating cardiac output. The current paradigm shift to explore trending ability rather than investigating agreement of absolute values alone is to be applauded. Future research should focus on the effectiveness of these devices in the context of (functional) haemodynamic monitoring before adoption into clinical practice can be recommended.

Non-Invasive Haemodynamic Monitoring in Pregnancy: A Comparative Study Using Ultrasound and Bioreactance

Background: Due to the importance of cardiovascular dysfunction and advances in the development and use of non-invasive cardiac output (CO) monitoring devices, there is a growing interest in their use in the obstetric population. The aim of this study was to compare two commercially available, non-invasive CO monitors in the assessment of heart rate (HR), stroke volume (SV), CO, cardiac index (CI) and total peripheral resistance (TPR) in an obstetric population. Methods: This was a prospective, comparative study including two groups. A normotensive group, which consisted of uncomplicated healthy pregnancies, and a hypertensive group, which consisted of those complicated by hypertensive disorders of pregnancy. Non-invasive cardiovascular assessments were performed using two methodologies. USCOM® is an operator-dependent Doppler ultrasound device which obtains velocity time integrals of transaortic blood flow at the left ventricular outflow tract, while NICOM® provides an operator-independent haemodynamic profile by assessing thoracic voltage changes (bioreactance) which reflect pulsatile blood flow in the thorax. Correlation coefficients were derived, and Bland-Altman analysis was performed to derive the mean percentage difference (MPD) between the devices. Results: 598 women were recruited for this study. In the normotensive group, 524 paired results were analysed, while 74 paired results were analysed in the hypertensive group. In the normotensive group, we found excellent correlation between USCOM® and NICOM® for HR (r = 0.885, p < 0.05), and moderate correlations for SV (r = 0.445, p < 0.05), CO (r = 0.529, p < 0.05), CI (r = 0.385, p < 0.05) and TPR (r = 0.524, p < 0.05). In the hypertensive group, we obtained similar correlations (HR: r = 0.877, p < 0.05; SV: r = 0.575, p < 0.05; CO: r = 0.601, p < 0.05; TPR: r = 0.589, p < 0.05). Bland-Altman analysis found that the agreement between both methodologies improved as gestation advances, with an MPD of 34% for CO estimation in the third trimester of uncomplicated pregnancies, and 39% in pregnancies complicated by hypertensive disorders. Conclusion: Our findings suggest that the two methodologies perform similarly in both uncomplicated pregnancies and in pregnancies complicated by hypertensive disorders. The study findings do not preclude the use of USCOM® and NICOM® devices in pregnancy, but indicate that these platforms cannot be used interchangeably. Our findings demonstrate an improvement in MPD as gestation advances and, therefore, questions the validity of previous longitudinal studies investigating maternal haemodynamics using these methodologies. Our work also highlights the need to construct reference ranges for each device and for validation of each methodology against a reference method before their use in research or clinical practice.

Effective evaluation of arterial pulse waveform analysis by two-dimensional stroke volume variation-stroke volume index plots.

Arterial pulse waveform analysis (APWA) with a semi-invasive cardiac output monitoring device is popular in perioperative hemodynamic and fluid management. However, in APWA, evaluation of hemodynamic data is not well discussed. In this study, we analyzed how we visually interpret hemodynamic data, including stroke volume variation (SVV) and stroke volume (SV) derived from APWA. We performed arithmetic estimation of the SVV-SV relationship and applied measured values to this estimation. We then collected measured values in six anesthesia cases, including three liver transplantations and three other types of surgeries, to apply them to this SVV-SVI (stroke volume variation index) plot. Arithmetic analysis showed that the relationship between SVV and SV can be drawn as hyperbolic curves. Plotting SVV-SV values in the semi-logarithmic scale showed linear correlations, and the slopes of the linear regression lines theoretically represented average mean cardiac contractility. In clinical measurements in APWA, plotting SVV and SVI values in the linear scale and the semi-logarithmic scale showed the correlations represented by hyperbolic curves and linear regression lines. The plots approximately shifted on the rectangular hyperbolic curves, depending on blood loss and blood transfusion. Arithmetic estimation is close to real measurement of the SVV-SV interaction in hyperbolic curves. In APWA, using SVV as an index of preload and the cardiac index or SVI derived from arterial pressure-based cardiac output as an index of cardiac function, is likely to be appropriate for categorizing hemodynamic stages as a substitute for Forrester subsets.

Minimally invasive or noninvasive cardiac output measurement: an update.

Although cardiac output (CO) by pulmonary artery catheterization (PAC) has been an important guideline in clinical management for more than four decades, some studies have questioned the clinical efficacy of CO in certain patient populations. Further, the use of CO by PAC has been linked to numerous complications including dysrhythmia, infection, rupture of pulmonary artery, injury to adjacent arteries, embolization, pulmonary infarction, cardiac valvular damage, pericardial effusion, and intracardiac catheter knotting. The use of PAC has been steadily declining over the past two decades. Minimally invasive and noninvasive CO monitoring have been studied in the past two decades with some evidence of efficacy. Several different devices based on pulse contour analysis are available currently, including the uncalibrated FloTrac/Vigileo system and the calibrated PiCCO and LiDCO systems. The pressure-recording analytical method (PRAM) system requires only an arterial line and is commercially available as the MostCare system. Transesophageal echocardiography (TEE) can measure CO by non-Doppler- or Doppler-based methods. The partial CO2 rebreathing technique, another method to measure CO, is marketed by Novametrix Medical Systems as the NICO system. Thoracic electrical bioimpedance (TEB) and electric bioreactance (EB) are totally noninvasive CO monitoring. Nexfin HD and the newer ClearSight systems are examples of noninvasive CO monitoring devices currently being marketed by Edwards Lifesciences. The developing focus in CO monitoring devices appears to be shifting to tissue perfusion and microcirculatory flow and aimed more at markers that indicate the effectiveness of circulatory and microcirculatory resuscitations.

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.