Method For Cardiac Output Monitoring Research Articles

Cardiac Output Measurement in Neonates and Children Using Noninvasive Electrical Bioimpedance Compared With Standard Methods: A Systematic Review and Meta-Analysis.

To systematically review and meta-analyze the validity of electrical bioimpedance-based noninvasive cardiac output monitoring in pediatrics compared with standard methods such as thermodilution and echocardiography. Systematic searches were conducted in MEDLINE and EMBASE (2000-2019). Method-comparison studies of transthoracic electrical velocimetry or whole body electrical bioimpedance versus standard cardiac output monitoring methods in children (0-18 yr old) were included. Two reviewers independently performed study selection, data extraction, and risk of bias assessment. Mean differences of cardiac output, stroke volume, or cardiac index measurements were pooled using a random-effects model (R Core Team, R Foundation for Statistical Computing, Vienna, Austria, 2019). Bland-Altman statistics assessing agreement between devices and author conclusions about inferiority/noninferiority were extracted. Twenty-nine of 649 identified studies were included in the qualitative analysis, and 25 studies in the meta-analyses. No significant difference was found between means of cardiac output, stroke volume, and cardiac index measurements, except in exclusively neonatal/infant studies reporting stroke volume (mean difference, 1.00 mL; 95% CI, 0.23-1.77). Median percentage error in child/adolescent studies approached acceptability (percentage error less than or equal to 30%) for cardiac output in L/min (31%; range, 13-158%) and stroke volume in mL (26%; range, 14-27%), but not in neonatal/infant studies (45%; range, 29-53% and 45%; range, 28-70%, respectively). Twenty of 29 studies concluded that transthoracic electrical velocimetry/whole body electrical bioimpedance was noninferior. Transthoracic electrical velocimetry was considered inferior in six of nine studies with heterogeneous congenital heart disease populations. The meta-analyses demonstrated no significant difference between means of compared devices (except in neonatal stroke volume studies). The wide range of percentage error reported may be due to heterogeneity of study designs, devices, and populations included. Transthoracic electrical velocimetry/whole body electrical bioimpedance may be acceptable for use in child/adolescent populations, but validity in neonates and congenital heart disease patients remains uncertain. Larger studies in specific clinical contexts with standardized methodologies are required.

Comparison between capnodynamic and thermodilution method for cardiac output monitoring during major abdominal surgery: An observational study.

BACKGROUNDCardiac output (CO) monitoring is the basis of goal-directed treatment for major abdominal surgery. A capnodynamic method estimating cardiac output (COEPBF) by continuously calculating nonshunted pulmonary blood flow has previously shown good agreement and trending ability when evaluated in mechanically ventilated pigs.OBJECTIVESTo compare the performance of the capnodynamic method of CO monitoring with transpulmonary thermodilution (COTPTD) in patients undergoing major abdominal surgery.DESIGNProspective, observational, method comparison study. Simultaneous measurements of COEPBF and COTPTD were performed before incision at baseline and before and after increased (+10 cmH2O) positive end-expiratory pressure (PEEP), activation of epidural anaesthesia and intra-operative events of hypovolemia and low CO. The first 25 patients were ventilated with PEEP 5 cmH2O (PEEP5), while in the last 10 patients, lung recruitment followed by individual PEEP adjustment (PEEPadj) was performed before protocol start.SETTINGKarolinska University Hospital, Stockholm, Sweden.PATIENTSIn total, 35 patients (>18 years) scheduled for major abdominal surgery with advanced hemodynamic monitoring were included in the study.MAIN OUTCOME MEASURES AND ANALYSISAgreement and trending ability between COEPBF and COTPTD at different clinical moments were analysed with Bland--Altman and four quadrant plots.RESULTSIn total, 322 paired values, 227 in PEEP5 and 95 in PEEPadj were analysed. Respectively, the mean COEPBF and COTPTD were 4.5 ± 1.0 and 4.8 ± 1.1 in the PEEP5 group and 4.9 ± 1.2 and 5.0 ± 1.0 l min−1 in the PEEPadj group. Mean bias (levels of agreement) and percentage error (PE) were −0.2 (−2.2 to 1.7) l min−1 and 41% for the PEEP5 group and −0.1 (−1.7 to 1.5) l min−1 and 31% in the PEEPadj group. Concordance rates during changes in COEPBF and COTPTD were 92% in the PEEP5 group and 90% in the PEEPadj group.CONCLUSIONCOEPBF provides continuous noninvasive CO estimation with acceptable performance, which improved after lung recruitment and PEEP adjustment, although not interchangeable with COTPTD. This method may become a tool for continuous intra-operative CO monitoring during general anaesthesia in the future.TRIAL REGISTRATIONClinicaltrials.gov identifier: NCT03444545.

Agreement between continuous and intermittent pulmonary artery thermodilution for cardiac output measurement in perioperative and intensive care medicine: a systematic review and meta-analysis

BackgroundPulmonary artery thermodilution is the clinical reference method for cardiac output monitoring. Because both continuous and intermittent pulmonary artery thermodilution are used in clinical practice it is important to know whether cardiac output measurements by the two methods are clinically interchangeable.MethodsWe performed a systematic review and meta-analysis of clinical studies comparing cardiac output measurements assessed using continuous and intermittent pulmonary artery thermodilution in adult surgical and critically ill patients. 54 studies with 1522 patients were included in the analysis.ResultsThe heterogeneity across the studies was high. The overall random effects model-derived pooled estimate of the mean of the differences was 0.08 (95%-confidence interval 0.01 to 0.16) L/min with pooled 95%-limits of agreement of − 1.68 to 1.85 L/min and a pooled percentage error of 29.7 (95%-confidence interval 20.5 to 38.9)%.ConclusionThe heterogeneity across clinical studies comparing continuous and intermittent pulmonary artery thermodilution in adult surgical and critically ill patients is high. The overall trueness/accuracy of continuous pulmonary artery thermodilution in comparison with intermittent pulmonary artery thermodilution is good (indicated by a pooled mean of the differences < 0.1 L/min). Pooled 95%-limits of agreement of − 1.68 to 1.85 L/min and a pooled percentage error of 29.7% suggest that continuous pulmonary artery thermodilution barely passes interchangeability criteria with intermittent pulmonary artery thermodilution.PROSPERO registration number CRD42020159730.

Impedance cardiography (electrical velocimetry) and transthoracic echocardiography for non-invasive cardiac output monitoring in pediatric intensive care patients: a prospective single-center observational study.

IntroductionElectrical velocimetry (EV) is a type of impedance cardiography, and is a non-invasive and continuously applicable method of cardiac output monitoring. Transthoracic echocardiography (TTE) is non-invasive but discontinuous.MethodsWe compared EV with TTE in pediatric intensive care patients in a prospective single-center observational study. Simultaneous, coupled, left ventricular stroke volume measurements were performed by EV using an Aesculon® monitor and TTE (either via trans-aortic valve flow velocity time integral [EVVTI], or via M-mode [EVMM]). H0: bias was less than 10% and the mean percentage error (MPE) was less than 30% in Bland–Altman analysis between EV and TTE. If appropriate, data were logarithmically transformed prior to Bland–Altman analysis.ResultsA total of 72 patients (age: 2 days to 17 years; weight: 0.8 to 86 kg) were analyzed. Patients were divided into subgroups: organ transplantation (OTX, n =28), sepsis or organ failure (SEPSIS, n =16), neurological patients (NEURO, n =9), and preterm infants (PREM, n =26); Bias/MPE for EVVTI was 7.81%/26.16%. In the EVVTI subgroup analysis for OTX, NEURO, and SEPSIS, bias and MPE were within the limits of H0, whereas the PREM subgroup had a bias/MPE of 39.00%/46.27%. Bias/MPE for EVMM was 8.07%/37.26% where the OTX and NEURO subgroups were within the range of H0, but the PREM and SEPSIS subgroups were outside the range. Mechanical ventilation, non-invasive continuous positive airway pressure ventilation, body weight, and secondary abdominal closure were factors that significantly affected comparison of the methods.ConclusionsThis study shows that EV is comparable with aortic flow-based TTE for pediatric patients.

Non-invasive cardiac output evaluation in postoperative cardiac surgery patients, using a new prolonged expiration-based technique

The gold standard methods to measure cardiac output (CO) are invasive and expose the patient to high risks of various complications. The aim of this study is to assess an innovative non-invasive method for CO monitoring in mechanically ventilated patients after cardiac surgery and its agreement with values obtained by thermodilution technique. Continuous monitoring of respiratory gas concentrations and airflow allows the estimation of CO through a newly developed algorithm derived from a modified version of the Fick equation. It consists of two phases: the first involves measurements during steady breathing state, and the second starts when a sudden perturbation into the carbon dioxide elimination process is introduced by a prolonged expiration. This prospective clinical study involved thirty-five adult patients, undergone cardiac surgery. The measurements were performed in curarized and haemodynamically stable patients, during the post-surgery recovery in intensive care unit. The study protocol, which lasted 1h for each patient, consisted of 20 measurements obtained by prolonged expiration-based method and 10 by thermodilution. The estimation of CO using the proposed method (COK) agreed with the thermodilution (COT) as demonstrated by: a low mean bias between COK and COT considering all patients (i.e., -0.11Lmin(-1)); a best fitting line having slope=0.98, r=0.81, p<0.0001; the lower and upper limits of agreement were -0.77 and +0.54Lmin(-1), respectively. COK shows a mean percentage error of 34%. In stable mechanically ventilated patients, undergone cardiac surgery, the proposed method is reliable if compared to the thermodilution. Considering the non-invasivity of the technique, further evaluations of its performances are encouraged.

Newer methods of cardiac output monitoring.

Cardiac output (CO) is the volume of blood ejected by each ventricle per minute and is the product of stroke volume and heart rate. CO can thus be manipulated by alteration in heart rate or rhythm, preload, contractility and afterload. Moreover it gives important information about tissue perfusion and oxygen delivery. CO can be measured by various methods and thermodilution method using pulmonary artery catheter (PAC) is till date considered as gold standard method. Complications associated with PAC led to development of newer methods which are minimally or non-invasive. Newer methods fulfil other properties like continuous and reproducible reading, cost effective, reliable during various physiological states and have fast response time. These methods are validated against the gold standard with good level agreement. In this review we have discussed various newer methods of CO monitoring and their effectiveness in clinical use.

전기적 임피던스 방법을 통한 hand-held 타입의 심박출량 모니터링 시스템 개발 및 검증

The impedance cardiogram has been proposed as a non-invasive, continuous, operator independent, and cost-effective method for cardiac output monitoring. However, it can not be completely considered as non-restrictive method beacuse of attached spot and band type electrodes. Therefore, we developed a improved convenient hand-held typed measurement system for cardiac output by electrical impedance technique. 80 subjects from Yonsei University and the surrounding areas, participated. All subjects measured stroke volume and cardiac output through Physioflow and developed system. To verify the developed system, statistical methods such as correlation, Wilcoxon signed ranks test, and the Bland-Altman analysis were used. The proposed system showed significant correlation in both male and female stroke volume(r=0.715, r=0.704) and cardiac output(r=0.826; r=0.804). From these results, it can be concluded that stroke volume and cardiac output could be improved convenient measurement using the both hands without the help of a specialist.

Clinical evaluation and advancement of perioperative minimally-invasive cardiac output monitoring methods

Background Perioperative cardiac output (CO) monitoring of critical patients is one of the objective indicators of cardiac functions. In recent years, along with the development of software, perioperative minimally-invasive cardiac output monitoring methods get more and more attractive. Objective To summarize the new progress of perioperative minimally-invasive cardiac output monitoring and objectively evaluate their role of perioperative hemodynamic monitoring. Content The basic principle of perioperative minimally-invasive cardiac output monitoring methods (FTV, PiCCO and Modelflow)were summed up.Enumerate the clinical research to compare their accuracy with invasive(Swan-Ganz) or non-invasive(TEE) cardiac output monitoring methods. Estimate the advantages and limitations of three methods. Trend Perioperative minimally -invasive cardiac output monitoring methods are simple and safe, less trauma, high accuracy and can continuously record cardiac output and related hemodynamic parameters. Perioperative minimally-invasive cardiac output monitoring reflect the state of the cardiovascular system promptly and effectively guide therapy in critical patients undergoing anesthesia. It will be more important and widely used in the future. Key words: Cardiac output; Arterial pulse wave; Thermodilution; Modelflow model

Pressure recording analytical method for cardiac output monitoring in children with congenital heart disease

The Swan-Ganz catheter cannot be considered the gold standard in the pediatric setting for cardiac output (CO) monitoring, due to the unavailability of pulmonary artery catheters (PACs) of adequate size for children of all ages and weights and due to peculiar cardiovascular anatomies of some children with congenital heart disease (CHD). The pressure recording analytical method (PRAM) is designed for arterial pressure-derived continuous CO measurement and it does not need any starting calibration, central venous catheterization, or adjustments based on experimental data. The aim of this study was to validate PRAM in a cohort of children with CHD.

Cardiac output measurement using an ultrasound dilution method: A validation study in ventilated piglets

To assess agreement between a new method of cardiac output monitoring, using ultrasound dilution technology and ultrasound transit time-based measurement of pulmonary blood flow in a piglet model. Prospective, experimental juvenile animal study. Animal laboratory of a university hospital. Nine random-bred piglets. After the animals received general anesthesia, we placed intravascular arterial and central venous catheters with the tip positioned in the abdominal aorta and the right atrium, respectively. The catheters were connected to the ultrasound dilution cardiac output monitor. An ultrasound transit time perivascular flow probe was positioned around the common pulmonary artery and served as the standard reference measurement. Cardiac output was manipulated during the experiment by creating hemorrhagic hypotension. Ultrasound dilution cardiac output was measured intermittently with injection volumes of 0.5 mL/kg and 1.0 mL/kg of isotonic saline at body temperature. Ultrasound dilution cardiac output (Q) measurement was compared with pulmonary blood flow (Q). Bias, defined as Q minus Q, was calculated for each measurement. Mean bias with standard deviation was calculated for measurements with volumes of injected saline, 0.5 mL/kg and 1.0 mL/kg, and compared using the Mann-Whitney U test. Mean bias (sd) between Q and Q was 0.040 (0.132) and 0.058 (0.136) L/min for measurement with 0.5 mL/kg and 1.0 mL/kg of isotonic saline, respectively (no statistically significant difference). Ultrasound dilution cardiac output measurement is reliable in piglets with the use of a small volume of a nontoxic indicator (isotonic saline).

Cardiac output measurement is feasible in the presence of left-to-right shunt with ultrasound dilution method: a validation study in lambs

It remains a great challenge to measure systemic blood flow in critically ill newborns, especially during the transitional period with intracardiac and extracardiac shunts. Due to technical restraints, size limitations, the necessity for a relatively large amount of blood withdrawn and possible indicator toxicity, many methods of cardiac output monitoring are not feasible, hence cardiac output is generally estimated from indirect parameters of systemic blood flow. In a former study we assessed the agreement for cardiac output using the ultrasound dilution method (UDCO) and ultrasound transit time-based measurement of main pulmonary blood flow in a juvenile piglet model without shunts [1]. In the present study we analyzed the influence of a left-to-right shunt on the agreement between UDCO and ultrasonic transit time pulmonary blood flow in a juvenile lamb model.

The Effects of Crystalloid and Colloid Preload on Cardiac Output in the Parturient Undergoing Planned Cesarean Delivery Under Spinal Anesthesia: A Randomized Trial

Hypotension after spinal anesthesia for cesarean delivery remains a major clinical problem. Fluid preloading regimens together with vasopressors have been used to reduce its incidence. Previous studies have used noninvasive arterial blood pressure measurement and vasopressor requirements to evaluate the effect of preload. We used a suprasternal Doppler flow technique to measure maternal cardiac output (CO) and corrected flow time (FTc, a measure of intravascular volume) before and after spinal anesthesia after 3 fluid preload regimens. We hypothesized that colloid solutions, compared with crystalloid, would produce the largest increase in CO and have the lowest incidence of hypotension. Sixty healthy term women scheduled for planned cesarean delivery under spinal anesthesia were recruited for this randomized, double-blind study. Baseline heart rate, systolic blood pressure (SBP), CO, and FTc were recorded in the left lateral tilt position. Patients were randomized to receive 1 of 3 fluid preload regimens given over 15 min: 1.5 L crystalloid (Hartman's solution), 0.5 L of 6% w/v hydroxyethyl starch (HES) solution (HES 0.5), or 1 L of 6% w/v HES solution (HES 1.0). Further measurements were made after fluid loading every 5 min for 30 min. After 30 min, spinal anesthesia was induced with hyperbaric bupivacaine 12.5 mg with fentanyl 15 microg and recordings were continued every 5 min for 20 min or until surgery started. The primary outcome, CO, was compared among groups. The incidence of hypotension (defined as a 20% reduction in SBP from the baseline), ephedrine use, and umbilical cord blood gases were also compared. Patient characteristics, heart rate, SBP, and cord gases were similar among groups. Although CO and FTc increased after preload in all groups (P < 0.005), this was only maintained with HES 1.0 after spinal anesthesia (P < 0.005). There were no differences among groups in the incidence of hypotension (70% vs 35% vs 65% for Hartman's solution, HES 0.5, and HES 1.0, respectively; P = 0.069) or mean ephedrine dose (10.4 vs 5.7 vs 9.7 mg; P = 0.26). Despite CO and FTc increases after fluid preload, particularly with HES 1.0 L, hypotension still occurred. The data suggest that CO increases after these preload regimens cannot compensate for reductions in arterial blood pressure after spinal anesthesia.

Noninvasive Assessment of Cardiac Index in Healthy Volunteers: A Comparison Between Thoracic Impedance Cardiography and Doppler Echocardiography

Thoracic bioimpedance cardiography (ICG) has been proposed as a noninvasive, continuous, operator-independent, and cost-effective method for cardiac output monitoring. In the present study, we compared cardiac index (CI) measurements with ICG (Niccomo device) and transthoracic Doppler echocardiography in resting healthy volunteers undergoing hemodynamic load challenge. Twenty-five healthy volunteers (7 men and 18 women, mean age 36 +/- 6 yr, body surface area 1.75 +/- 0.17 m(2)) were investigated during three experimental conditions: baseline, positive end-expiratory pressure + 10 cm H(2)O and lower body positive pressure by means of medical antishock trousers inflated to 30 cm H(2)O in the abdominal compartment. ICG signal quality was >89% over all sets of measurements. A weak but significant relationship was observed between CI(TTE) and CI(ICG) (r = 0.36; P = 0.002). Agreement between both techniques was 0.94 L x min(-1) x m(-2) (95% CI: 0.77-1.11), limits of agreement were -0.47 to 2.35 L x min(-1) x m(-2), and percentage error was 53%. No statistically significant relationships were found between percent changes in CI(TTE) and CI(ICG) after applications of positive end-expiratory pressure + 10 cm H(2)O (r = 0.21; P = 0.31) and medical antishock trousers (r = 0.22; P = 0.30). Poor correlation and lack of agreement between absolute values of CI measured by ICG and transthoracic Doppler echocardiography were found in resting healthy volunteers. The Niccomo device was also unreliable for monitoring changes in CI during hemodynamic load challenge.

Comparison between Flotrac-Vigileo and Bioreactance, a totally noninvasive method for cardiac output monitoring

IntroductionThis study was designed to compare the clinical acceptability of two cardiac output (CO) monitoring systems: a pulse wave contour-based system (FloTrac-Vigileo) and a bioreactance-based system (NICOM), using continuous thermodilution (PAC-CCO) as a reference method.MethodsConsecutive patients, requiring PAC-CCO monitoring following cardiac surgery, were also monitored by the two other devices. CO values obtained simultaneously by the three systems were recorded continuously on a minute-by-minute basis.ResultsContinuous recording was performed on 29 patients, providing 12,099 simultaneous measurements for each device (417 ± 107 per patient). In stable conditions, correlations of NICOM and Vigileo with PAC-CCO were 0.77 and 0.69, respectively. The bias was -0.01 ± 0.84 for NICOM and -0.01 ± 0.81 for Vigileo (NS). NICOM relative error was less than 30% in 94% of the patients and less than 20% in 79% vs. 91% and 79% for the Vigileo, respectively (NS). The variability of measurements around the trend line (precision) was not different between the three methods: 8 ± 3%, 8 ± 4% and 8 ± 3% for PAC-CCO, NICOM and Vigileo, respectively. CO changes were 7.2 minutes faster with Vigileo and 6.9 minutes faster with NICOM (P < 0.05 both systems vs. PAC-CCO, NS). Amplitude of changes was not significantly different than thermodilution. Finally, the sensitivity and specificity for predicting significant CO changes were 0.91 and 0.95 respectively for the NICOM and 0.86 and 0.92 respectively for the Vigileo.ConclusionsThis study showed that the NICOM and Vigileo devices have similar monitoring capabilities in post-operative cardiac surgery patients.

Semi-continuous versus injectate cardiac output measurement in intensive care patients after cardiac surgery.

Commercially available semi-continuous cardiac output (SCCO) monitoring systems are based on the pulsed warm thermodilution technique. There is evidence that SCCO fails to correlate with standard intermittent bolus cardiac output (ICO) in clinical situations with thermal instability in the pulmonary artery. Furthermore, ventilation may potentially influence thermodilution measurements by enhanced respiratory variations in pulmonary artery blood temperature and by cyclic changes in venous return. Therefore, we evaluated the correlation, accuracy and precision of SCCO versus ICO measurements before and after extubation. Prospective cohort study. Intensive care unit (ICU) of a university hospital. 22 cardiac surgical ICU patients. None. SCCO and ICO data were obtained at nine postoperative time points while the patients were on controlled mechanical ventilation. Further sets of measurements were taken during the weaning phase 20 min before extubation, and 5 min, 20 min and 1 h after extubation. SCCO and ICO measurements yielded 286 data pairs with a range of 1.8-9.9 l/min for SCCO and 1.9-9.8 l/min for ICO. The correlation between SCCO and ICO was highly significant (r = 0.92; p < 0.01), accompanied by a bias of -0.052 l/min and a precision of 0.56 l/min. Correlation, accuracy and precision were not influenced by the mode of respiration. Our results demonstrate excellent correlation, accuracy and precision between SCCO and ICO measurements in postoperative cardiac surgical ICU patients. We conclude that SCCO monitoring offers a reliable clinical method of cardiac output monitoring in ICU patients following cardiac surgery.