Impedance cardiography for cardiac output estimation: reliability of wrist-to-ankle electrode configuration

Comparing elective and emergency caesarean section by using bioimpedance method

BACKGROUND

There are limited studies focusing on hemodynamic changes between elective and emergent C/S cases. We considered that a better understanding of the alterations and physiological reactions in both situations with non-invasive novel technologies might be useful in managing maternal and fetal sides.

METHODS

In this prospective observational study, non-invasive hemodynamic changes were observed by using the whole-body impedance method using the NICaS™ device. CO, cardiac index (CI), stroke volume (SV), stroke index (SI), total peripheric resistance (TPR), and cardiac reserve (GGI) parameters were evaluated with a non-invasive method. Measurements were done initiating before surgery, 9 times of 5 min intervals.

RESULTS

All 95 patients finished the study. 47 cesarean sections were in the elective group, 48 were in the emergent group. SV in 4.5.6. time intervals were statistically increased in the elective group (p values: SvMl4: 0.025, SvMl5: 0.049, SvMl6: 0.044) (p < 0.05). SI in the second-time interval was statistically increased in the emergent group (p-value SI2: 0.047) (p < 0.05). SI in the 4th time interval was statistically increased in the elective group (p-value SI4: 0.047) (p < 0.05). CO measurements were not statistically different between groups in all time intervals for all comparisons. CI in the second time interval was statistically decreased in the elective group (p-value CI2: 0.012) (p < 0.05). GGI in the 4th time interval was statistically increased in the elective group (p-value GGI4: 0.035) (p < 0.05). TPRI in the second time interval was statistically increased in the elective group (p-value TPRI 2: 0.014) (p < 0.05).

CONCLUSIONS

Understanding normal hemodynamic values before, during, and after C/S is feasible and might help the clinician assess patients' cardiac performance with a reliable noninvasive technique. NICaS might be a reliable tool to evaluate patients' baseline values and diagnose complications earlier during the surgery.

Can non-invasive cardiac hemodynamics and fluid content system (NICaS) parameters predict Acute Heart Failure outcomes in Caucasian and Asian patients in the emergency department?

PURPOSE

Acute heart failure (AHF) is a serious condition that requires prompt diagnosis and management. To optimize patient care, clinicians need a reliable, non-invasive method to assess hemodynamic parameters and total body congestion. Currently, no standardized technology is widely used for this purpose. However, NICaS technology, which measures hemodynamic parameters based on regional bioimpedance, has shown promise in monitoring AHF patients in a non-invasive and reliable manner. In this study, researchers aimed to evaluate the usefulness of NICaS technology in predicting patients' outcome in Caucasian and Asian AHF patients presenting to the emergency department (ED).

PATIENTS AND METHODS

The study included 40 Caucasian patients from Italy (group A) and 71 Asian patients from Indonesia and Singapore (group B) with a diagnosis of AHF in the ED. The study compared data from NICaS parameters, clinical findings, laboratory, and radiological results with short-term events.

RESULTS

In group A, NICaS data at ED arrival significantly predicted 30-day cardiovascular mortality and rehospitalization. At discharge, a value of cardiac output obtained using NICaS was a significant predictor for 30-day rehospitalization. In group B, NICaS variables, total peripheral resistance index on admission and during 48-72 ​h had prominent AUC compared to clinical congestion score and NT-proBNP in predicting mortality and rehospitalization.

CONCLUSIONS

The results indicate that NICaS technology offers a simple, non-invasive, and reliable method of assessing cardiac hemodynamics and congestion in AHF patients. These measurements may enhance diagnosis, tailor management plans, stratify risk, and predict outcomes in both Caucasian and Asian patients.

The Impact of Positive Inotropic Therapy on Hemodynamics and Organ Function in Acute Heart Failure: A Differentiated View

BACKGROUND

Little is known about the impact of treatment with inotropic drugs on the interaction of hemodynamics, biomarkers, and end-organ function in patients with acute decompensated heart failure (HF) of different origins and heart rhythms.

METHODS

Fifty patients with different causes of acute decompensated HF (dilated cardiomyopathy DCM, ischemic cardiomyopathy ICM, atrial fibrillation AF, sinus rhythm/pacemaker lead rhythm SR/PM) were treated with dobutamine or levosimendan. Non-invasive hemodynamics, biomarkers, and parameters of renal organ function were evaluated at hospital admission and after myocardial recompensation (day 5 to 7).

RESULTS

Twenty-seven patients with ICM and twenty-three patients with DCM were included. Thirty-nine patients were treated with dobutamine and eleven with levosimendan. Sixteen were accompanied by persistent AF and thirty-four presented either with SR or PM. In the overall cohort, body weight and biomarkers (NT-proBNP/ST2) significantly decreased. GFR significantly increased during therapy with either dobutamine or levosimendan. However, hemodynamic parameters seem to be only improved in patients with DCM, in the levosimendan sub-group, and in patients with SR/PM.

CONCLUSION

Patients with acute decompensated HF benefit from positive inotropic therapy during short-term follow-ups. In particular, patients with DCM, those after levosimendan therapy and those with SR/PM, seem to benefit most from inotropic therapy.

Noninvasive Hemodynamic Evaluation Following TAVI for Severe Aortic Stenosis

Background Various hemodynamic changes occur following transcatheter aortic valve implantation (TAVI) that may impact therapeutic decisions. NICaS is a noninvasive bioimpedance monitoring system aimed at hemodynamic assessment. We used the NICaS system in patients with severe aortic stenosis (AS) to evaluate short-term hemodynamic changes after TAVI. Methods and Results We performed hemodynamic analysis using NICaS on 97 patients with severe AS who underwent TAVI using either self-expandable (68%) or balloon-expandable (32%) valves. Patients were more often women (54%) and had multiple comorbidities including hypertension (83%), coronary artery disease (46%), and diabetes (37%). NICaS was performed at several time points-before TAVI, soon after TAVI, at hospital discharge, and during follow-up. Compared with baseline NICaS measurements, we observed a significant increase in systolic blood pressure and total peripheral resistance (systolic blood pressure 132±21 mm Hg at baseline versus 147±23 mm Hg after TAVI, P<0.001; total peripheral resistance 1751±512 versus 2084±762 dynes*s/cm⁵, respectively, P<0.001) concurrent with a decrease in cardiac output and stroke volume (cardiac output 4.2±1.5 versus 3.9±1.3 L/min, P=0.037; stroke volume 61.4±14.8 versus 56.2±15.9 mL, P=0.001) in the immediate post-TAVI period. At follow-up (median 59 days [interquartile range, 40.5-91]) these measurements returned to values that were not different from the baseline. A significant improvement in echocardiography-based left ventricular ejection fraction was observed from baseline to follow-up (55.6%±11.6% to 59.4%±9.4%, P<0.001). Conclusions Unique short-term adaptive hemodynamic changes were observed using NICaS in patients with AS soon after TAVI. Noninvasive hemodynamic evaluation immediately following TAVI may contribute to the understanding of complex hemodynamic changes and merits favorable consideration.

Correlation of Impedance Cardiography-Derived and Cardiac Magnetic Resonance-Derived Stroke Volumes

Cardiac output (CO) and other hemodynamic parameter measurements play an important role in the management of cardiovascular conditions; however, due to limitations of current day technologies, such measurements are either not routinely performed or incorporated into clinical practice. Moreover, measurement of these hemodynamic parameters in the outpatient setting at different time points to assess interval change is currently not feasible. We attempted to validate total-body impedance cardiography-based Non-Invasive Cardiac System (NICaS) derived stroke volume (SV) with that from cardiac magnetic resonance (CMR), a current day gold standard method of assessment. We compared SV, as it is the primary unit of measurement utilized by both technologies. Forty-one consecutive patients undergoing CMR were also investigated by NICaS following CMR. The consistency of non-invasive technology-derived SV measurement was validated by NICaS measurement in 10 subjects, both before and after CMR. Of the 41 enrolled patients; data from 38 patients was adequate for comparison (motion artifact prevented CMR measures in 3 patients). Fourteen patients (37%) were female; mean age was 55 ± 15 years (28-87 years) and body-mass index was 28.7 ± 5.5 kg/m² (20.5-41.9 kg/m²). Hypertrophic cardiomyopathy (9/41) was the most common study indication for CMR. NICaS-derived SV strongly correlated with CMR [NICaS 77 ± 20 ml (31-123 ml) and CMR 84 ± 23 ml (47-132 ml); P < 0.001; r = 0.77; ICC = 0.73]. The Bland-Altman limits of agreement between NICaS and CMR were -26.7% and 39.9%. NICaS-derived SV collected before and after MRI did not differ [80 ± 18 ml (51-102 ml) pre and 76 ± 17 ml (50-99 ml) post; P = 0.0007, Kappa = 1]. Agreement between NICaS-derived and CMR-derived SV was within the acceptable range of boundaries set by the US Food and the Drug Administration. Consistency in SV measurement at different time-points may allow use of this technology to identify interval hemodynamic changes noninvasively.

Association of Neutrophil Mediators With Dengue Disease Severity and Cardiac Impairment in Adults

BACKGROUND

Cardiac impairment contributes to hypotension in severe dengue (SD). However, studies examining pathogenic factors affecting dengue-associated cardiac impairment are lacking. We examined the role of neutrophil mediators on cardiac impairment in clinical dengue.

METHODS

We prospectively enrolled adult patients with dengue and controls. Cardiac parameters were measured using a bioimpedance device. Neutrophils mediators were measured, including myeloperoxidase (MPO) and citrullinated histone H3.

RESULTS

We recruited 107 dengue patients and 30 controls. Patients with dengue were classified according to World Health Organization 2009 guidelines (44 with dengue fever [DF], 51 with DF with warning signs, and 12 with SD). During critical phase, stroke index (P < .001), cardiac index (P = .03), and Granov-Goor index (P < .001) were significantly lower in patients with dengue than in controls. During critical phase, MPO was significantly higher in patients with dengue than in controls (P < .001) and also significantly higher in patients with SD than in those with DF. In addition, MPO was inversely associated with the stroke, cardiac, and Granov-Goor indexes, during the critical phase, and longitudinally as well.

CONCLUSIONS

Cardiac function was decreased, and MPO increased, during with critical phase in patients SD compared with those with DF and controls. MPO may mediate dengue-associated cardiac impairment.

Clinical and prognostic relevance of sST2 in adults with dengue-associated cardiac impairment and severe dengue

BACKGROUND

Dengue can be complicated by severe outcomes including cardiac impairment, and the lack of reliable prognostic biomarkers poses a challenge in managing febrile dengue patients. Here, we investigated the functionality of soluble suppressor of tumorigenicity (sST2) as a predictive marker of severe dengue and its association in dengue-associated cardiac impairment.

METHODS

Plasma samples, aged >16 years, collected from 36 dengue fever, 43 dengue with warning signs, 11 severe dengue (collected at febrile, critical and recovery phases) and 30 controls were assayed for plasma levels of sST2, troponin T and N-terminal (NT)-pro hormone brain natriuretic peptide (NT-proBNP) by ELISA. Cardiac parameters: stroke index (SI), cardiac index (CI) and Granov-Goor Index (GGI) were measured with a bioimpedance device during the different phases for dengue subjects and once for the controls.

PRINCIPAL FINDINGS

In the febrile, critical and early recovery phases, sST2 levels were significantly elevated in dengue participants and sST2 levels increased with increasing disease severity (P < 0.01 for all). sST2 concentrations were negatively correlated with SI (r = -0.48; P < 0.001, r = -0.55; P < 0.001), CI (r = -0.26; P = 0.02, r = -0.6: P < 0.001) and GGI (r = -0.44; P < 0.001, r = -0.57; P < 0.001) in the critical and early recovery phases. In contrast, sST2 levels in the febrile and critical phases, were positive correlated to troponin T (r = 0.44, P < 0.001; r = 0.22, P = 0.03, respectively) and NT-proBNP (r = 0.21, P = 0.03; r = 0.35, P < 0.001). ROC analysis demonstrated sST2 as a good biomarker of severe dengue in the critical phase, AUROC 0.79, P < 0.001.

CONCLUSION/SIGNIFICANCE

sST2 levels were elevated in patients with dengue especially in cases of severe dengue. Furthermore, increased sST2 levels were associated with cardiac indicators suggesting lower cardiac performance. While further research is needed to demonstrate its clinical utility, sST2 may be a useful prognostic biomarker of severe dengue.

Comparative study of cardiac output measurement by regional impedance cardiography and thermodilution method in patients undergoing off pump coronary artery bypass graft surgery

Background:

An ideal CO monitor should be noninvasive, cost effective, reproducible, reliable during various physiological states. Limited literature is available regarding the noninvasive CO monitoring in open chest surgeries.

Aim:

The aim of this study was to compare the CO measurement by Regional Impedance Cardiography (RIC) and Thermodilution (TD) method in patients undergoing off pump coronary artery bypass graft surgery (OPCAB).

Settings and Design:

We conducted a prospective observational comparative study of CO measurement by the noninvasive RIC method using the NICaS Hemodynamic Navigator system and the gold standard TD method using pulmonary artery catheter in patients undergoing OPCAB. A total of 150 data pair from the two CO monitoring techniques were taken from 15 patients between 40-70 years at various predefined time intervals of the surgery.

Patients and Methods:

We have tried to find out the accuracy, precision and cost effectiveness of the newer RIC technique. Mean CO, bias and precision were compared for each pair i.e.TD-CO and RIC-CO as recommended by Bland and Altman. The Sensitivity and specificity of cutoff value to predict change in TD-CO was used to create a Receiver operating characteristic or ROC curve.

Results:

Mean TD-CO values were around 4.52 ± 1.09 L/min, while mean RIC- CO values were around 4.77± 1.84 L/min. The difference in CO change was found to be statistically not significant (p value 0.667). The bias was small (-0.25). The Bland Altman plot revealed a mean difference of -0.25 litres. The RIC method had a sensitivity of 55.56 % and specificity of 33.33 % in predicting 15% change in CO of TD method and the total diagnostic accuracy was 46.67%.

Conclusion:

A fair correlation was found between the two techniques. The RIC method may be considered as a promising noninvasive, potentially low cost alternative to the TD technique of hemodynamic measurement.

In Search of Clinical Impact: Advanced Monitoring Technologies in Daily Heart Failure Care

Despite significant advances in the management of heart failure (HF), further improvement in the outcome of this chronic and progressive disease is still considered a major unmet need. Recurrent hospitalizations due to decompensated HF frequently occur, resulting in increased morbidity and mortality rates. Past attempts at early detection of clinical deterioration were mainly based on monitoring of signs and symptoms of HF exacerbation, which have mostly given disappointing results. Extensive research of the pathophysiology of HF decompensation has indicated that hemodynamic alterations start days prior to clinical manifestation. Novel technologies aim to monitor these minute hemodynamic changes, allowing time for therapeutic interventions to prevent hemodynamic derangement and HF exacerbation. The latest noticeable advancements include assessment of lung fluid volume, wearable devices with integrated sensors, and microelectromechanical systems-based implantable devices for continuous measurement of cardiac filling pressures. This manuscript will review the rationale for monitoring HF patients and discuss previous and ongoing attempts to develop clinically meaningful monitoring devices to improve daily HF health care, with particular emphasis on the recent advances and clinical trials relevant to this evolving field.

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

OBJECTIVE

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.

DATA SOURCES

Systematic searches were conducted in MEDLINE and EMBASE (2000-2019).

STUDY SELECTION

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.

DATA EXTRACTION

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.

DATA SYNTHESIS

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.

CONCLUSIONS

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.

Cardiac Function and Hemodynamic Changes during Minimally Invasive Hysterectomy with Pneumoperitoneum and Steep Trendelenburg Position for Patients with Endometrial Cancer Who Are Obese

STUDY OBJECTIVE

To assess the effect of carbon dioxide (CO₂) pneumoperitoneum and steep Trendelenburg position on patients' cardiac function and hemodynamics during minimally invasive staging surgery for endometrial cancer.

DESIGN

Single-center prospective longitudinal study.

SETTING

University-affiliated tertiary hospital.

PATIENTS

Patients with endometrial cancer undergoing minimally invasive surgery.

INTERVENTIONS

After consent, the patients' hemodynamic parameters were assessed by the Non-Invasive Cardiac System (NI Medical, Petah Tikva, Israel) at 5 time points: before general anesthesia, after induction of general anesthesia, after CO₂ insufflation of the peritoneum, after steep Trendelenburg position, and at the end of surgery.

MEASUREMENTS AND MAIN RESULTS

Twenty-three women were recruited. The median age of the patients was 68 years (interquartile range [IQR] 62-75), with a median body mass index of 34.9 kg/m² (IQR 31.2-39.5) and an American Society of Anesthesiologists score ≥2. The initial median mean arterial pressure was 108 mmHg (IQR 101-113), and the baseline median cardiac output was 7.2 L/min (IQR 5.6-8.7). The median mean arterial pressure significantly decreased by 18% after insufflation (p = .001), again after Trendelenburg position (p = .003), and did not fully recover at the end of surgery in comparison with the preanesthesia baseline (p = .001). The median stroke volume significantly decreased by 17% after insufflation compared with the baseline (p = .01) and then gradually recovered to the baseline levels by the end of surgery. The median cardiac power significantly decreased by 35% after insufflation (0.009), remained low during Trendelenburg position (p = .009), and recovered by the end of surgery to 18% below the baseline levels (p = .035).

CONCLUSION

Significant hemodynamic changes occur during minimally invasive staging surgery for endometrial cancer. CO₂ insufflation is accompanied by the most dramatic hemodynamic deterioration during surgery, and this does not get affected much with Trendelenburg. Knowledge of the hemodynamic values of women classified as high risk when using a noninvasive technique during surgery is obtainable and may assist both surgeon and anesthesiologist to ensure a safer procedure.

Assessing Patent Ductus Arteriosus (PDA) Significance on Cardiac Output by Whole-Body Bio-impedance

We evaluated the effectiveness of a whole-body bioimpedance device (NICaS®, NI Medical, Petach Tikva, Israel) to predict the presence of a hemodynamically significant patent ductus arteriosus (PDA) in premature infants. A total of 36 infants less than 35 week's gestation age and birth weights of less than 1750 g were included in the study. Using the NICaS® device, we obtained whole-body bioimpedance measurements of stroke volume index (SI), cardiac output index (CI) and total peripheral resistance index. A total of 61 measurements were taken together with echocardiograph imaging. The study population was divided into three groups according to the echocardiograph results: group 1-small PDA, group 2-moderate PDA, and group 3-large PDA. Both SI and CI significantly increased from a median value of 22.6 ml/m² and 3.4 l/min/m² to 23.8 and 3.7, to 39.8 and 5.4 between groups 1, 2 and 3 respectively. The difference was statistically significant between groups 1 and 3 (P = 0.005 for SI and P = 0.002 for CI) and between groups 2 and 3 (P = 0.037 for SI and P = 0.05 for CI). We found statistically significant differences in SI and CI between infants with large PDAs and infants with no or small and medium PDAs. We suggest that these differences can be used in real time, in addition to echocardiography, in assessing the presence of significant PDAs.

A Noninvasive Stroke Volume Monitoring for Early Detection of Minimal Blood Loss: A Pilot Study

INTRODUCTION

Alternation in traditional vital signs can only be observed during advanced stages of hypovolemia and shortly before the hemodynamic collapse. However, even minimal blood loss induces a decrease in the cardiac preload which translates to a decrease in stroke volume, but these indices are not readily monitored. We aimed to determine whether minor hemodynamic alternations induced by controlled and standardized hypovolemia can be detected by a whole-body bio-impedance technology.

METHODS

This was a non-randomized controlled trial that enrolled healthy blood donors. Vital signs, as well as shock index and stroke volume (SV), were recorded using noninvasive cardiac system, a noninvasive whole-body impedance-based hemodynamic analysis system, during phlebotomy.

RESULTS

Sixty subjects were included in the study group and 20 in the control group. Blood loss of 450 mL resulted in a significant decrease in systolic blood pressure (5 mm Hg; 95% CI 3, 6) and SV (5.07 mL; 95% CI 3.21, 6.92), and increase in shock index (0.03 bpm/mm Hg; 95% CI 0.01, 0.05). Clinically detectable changes (≥10%) in blood pressure and shock index were detectable in 15% and 5%, respectively. SV decreased by more than 10% in 40% of blood donors. No significant changes occurred in the control group.

CONCLUSION

Continuous noninvasive monitoring of SV may be superior to conventional indices (e.g., heart rate, blood pressure, or shock index) for early identification of acute blood loss. As an operator-independent and point-of-care technology, the SV whole body bio-impedance measurement may assist in accurate monitoring of potentially bleeding patients and early identification of hemorrhage.

Early post-stress decrease in cardiac performance by impedance cardiography and its relationship to the severity and extent of ischemia by myocardial perfusion imaging

Background

While single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is a well-established noninvasive procedure for the evaluation of patients with coronary artery disease (CAD), it is unable to detect the presence of, or underestimates the extent of CAD in certain patients. We aimed to show that a bio-impedance device can detect early post-stress changes in several hemodynamic parameters, thereby serving as a potential marker for the presence of significant ischemia.

Methods

Prospectively enrolled patients, referred to our Medical Center for clinically-indicated MPI, underwent testing using a Non-Invasive Cardiac System (NICaS) before and immediately after exercise. The differences between rest and stress hemodynamic parameters were compared with the severity and extent of myocardial ischemia by MPI. The study included 198 patients; mean age was 62 years, 26% were women, 54% had hypertension, and 29% diabetes mellitus. Of them, 188 patients had ≤10%, and 10 had > 10% of myocardial ischemia.

Results

In the first group, there was a significantly greater increase in post-exercise stroke index, stroke work index, cardiac index and cardiac power index (19.2, 29.1, 90.5 and 107%, respectively) compared with the second group (− 2.7, 3.8, 43.7 and 53.5%, respectively), as well as a significantly greater decrease in total peripheral resistance index (− 38.7% compared with − 16.3%), with corresponding p values of 0.015, 0.017, 0.040, 0.016, and < 0.001, respectively.

Conclusions

Our data suggest that immediate post-stress changes in several hemodynamic parameters, detected by the NICaS, can be used as an important adjunct to SPECT MPI for the early detection of myocardial ischemia.

Controlled Study of Central Hemodynamic Changes in Inspiratory Exercise with Different Loads in Heart Failure

Background Inspiratory muscle weakness contributes to exercise intolerance and decreased quality of life in patients with heart failure. Studies with inspiratory muscle training show improvement in inspiratory muscle strength, functional capacity and quality of life. However, little is known about the central hemodynamic response (CHR) during inspiratory exercise (IE). Objective To evaluate CHR in a single IE session with different loads (placebo, 30% and 60%) in heart failure. Methods Randomized placebo-controlled clinical trial in patients with heart failure with reduced ejection fraction, functional class II and III. Twenty patients aged 65 ± 11 years completed a single session of inspiratory exercise, in 3 cycles of 15 minutes, with a 1-hour washout, involving loads of 30% (C30), 60% (C60) and placebo, using a linear load resistor (PowerBreathe Light). The noninvasive hemodynamic study was performed by cardiothoracic bioimpedance (Niccomo™ CardioScreen®). Statistical analysis was performed with Student's t-test and Pearson's correlation, and P≤0.05 was considered significant. Results An increase in heart rate (HR) was observed with C30 (64 ± 15 vs 69 ± 15 bpm; p = 0.005) and C60 (67 ± 14 vs 73 ± 14 bpm, p = 0.002). A decrease was observed in systolic volume (SV) with C30 (73 ± 26 vs 64 ± 20 ml; p = 0.004). Cardiac output (CO), on its turn, increased only with C60 (4.6 ± 1.5 vs 5.3 ± 1.7 l/min; p = -0.001). Conclusion When using the 60% load, in a single IE session, changes in CHR were observed. HR and CD increased, as did the Borg scales and subjective sensation of dyspnea. The 30% load reduced the SV. (Arq Bras Cardiol. 2020; 114(4):656-663).

Non-Invasive Hemodynamic Whole-Body Bioimpedance Indices for the Early Detection of Cancer Treatment-Related Cardiotoxicity: A Retrospective Observational Study

<b><i>Introduction:</i></b> Patients undergoing chemotherapy are extremely vulnerable to cardiotoxicity. Early detection of cardiac dysfunction is of vital importance to optimize the management of these patients. <b><i>Objective:</i></b> The aim of this study was to test the effectiveness of non-invasive hemodynamic whole-body bioimpedance (WBI) technology as a modality to detect heart failure in patients undergoing chemotherapy treatment. <b><i>Methods:</i></b> This retrospective observational trial included 84 patients treated at the cardio-oncology outpatient clinic of the Rabin Medical Center. Clinical assessments were performed including biomarker testing and measurement of hemodynamic and volume status parameters as measured by WBI. <b><i>Results:</i></b> We included 84 patients with a median age of 64.8 years, and 40.5% were males. Clinical heart failure was detected in 43% of the whole group. Patients were divided into two groups according to baseline NT-proBNP levels with a cut-off of 900 pg/mL. Left ventricular ejection fraction did not differ between the groups. Those with NT-proBNP &#x3e;900 pg/mL had lower levels of stroke index, cardiac index, and Granov-Goor index (GGI; 25.9 vs. 34.0, 2.0 vs. 2.3, 8.3 vs. 11.4, respectively, with <i>p</i> &#x3c; 0.001 for all comparisons). The optimal cut-off value for the GGI to detect NT-proBNP &#x3e;900 pg/mL was 8.3. The area under the curve of a GGI cut-off &#x3c;8.3 to detect NT-proBNP &#x3e;900 pg/mL was 0.81 (positive predictive value 95% and negative predictive value 72%), with a 51% sensitivity and 98% specificity. <b><i>Conclusion:</i></b> GGI, a parameter measured by WBI, can reliably correlate to biomarker evidence of heart failure in patients after chemotherapy. Its use as a screening tool for cardiotoxicity in patients with ongoing anticancer therapy is promising.

Hemodynamic response to fluid removal during hemodialysis: categorization of causes of intradialytic hypotension

Background

Intradialytic hypotension is a clinically significant problem, however, the hemodynamics that underlie ultrafiltration and consequent hypotensive episodes has not been studied comprehensively.

Methods

Intradialytic cardiac output, cardiac power and peripheral resistance changes from pretreatment measurements were evaluated using a novel regional impedance cardiographic device (NICaS, NI Medical, Peta Tikva, Israel) in 263 hemodialysis sessions in 54 patients in dialysis units in the USA and Brazil with the goal of determining the various hemodynamic trends as blood pressure decreases.

Results

Hypotensive episodes occurred in 99 (13.5%) of 736 intra- and postdialytic evaluations. The hemodynamic profiles of the episodes were categorized: (i) The cardiac power index significantly decreased in 35% of episodes by 36%, from 0.66 [95% confidence interval (CI) 0.60-0.72] to 0.43 (95% CI 0.37-0.48) [w/m2] with a small reduction in the total peripheral resistance index. (ii) The total peripheral resistance index significantly decreased in 37.4% of episodes by 33%, from 3342 (95% CI 2824-3859) to 2251 (95% CI 1900-2602) [dyn × s/cm5 × m2] with a small reduction in the cardiac power index. (iii) Both the cardiac power index and total peripheral resistance index significantly decreased in 27.3% of episodes, the cardiac power index by 25% from 0.63 (95% CI 0.57-0.70) to 0.48 (95% CI 0.42-0.53) [w/m2] and the total peripheral resistance index by 23% from 2964 (95% CI 2428-3501) to 2266 (95% CI 1891-2642).

Conclusions

The hemodynamic profiles clearly define specific hemodynamic mechanisms of cardiac power reduction and/or vasodilatation as underlying intradialytic hypotensive episodes. A reduction in cardiac power (reduction of both blood pressure and cardiac output) could be the result of preload reduction due to a high ultrafiltration rate with not enough refilling or low target weight. A reduction in peripheral resistance (reduction in blood pressure and increase in cardiac output) could be the result of relative vasodilatation as arteries do not contract to compensate for volume reduction due to autonomous dysfunction. As both phenomena are independent, they may appear at the same time. Based on these results, a reduction of ultrafiltration rate and an increase in target weight to improve preload or immediate therapeutic actions to increase peripheral resistance are rational measures that could be taken to maintain blood pressure and prevent hypotensive ischemic complications in dialysis patients.

Non-invasive hemodynamic profiling of patients undergoing hemodialysis - a multicenter observational cohort study

Background

Intradialytic blood pressure (BP) measurement is currently the main parameter used for monitoring hemodynamics during hemodialysis (HD). Since BP is dependent on cardiac output and total peripheral resistance, knowledge of these parameters throughout the HD treatment would potentially be valuable.

Methods

The use of a novel non-invasive monitoring system for profiling hemodynamic response patterns during HD was explored: a whole-body bio-impedance system was used to assess cardiac index (CI), total peripheral resistance index (TPRI), cardiac power index (CPI) among other parameters in chronic HD patients from 4 medical centers. Measurements were made pre, during and post dialysis. Patients were grouped into 5 hemodynamic profiles based on their main hemodynamic response during dialysis i.e. high TPRI; high CPI; low CPI; low TPRI and those with normal hemodynamics. Comparisons were made between the groups for baseline characteristics and 1-year mortality.

Results

In 144 patients with mean age of 67.3 ± 12.1 years pre-dialysis hemodynamic measurements were within normal limits in 35.4% but only 6.9% overall remained hemodynamically stable during dialysis. Intradialytic BP decreased in 65 (45.1%) in whom, low CPI (47 (72.3%)) and low TPRI (18 (27.7%) were recorded. At 1-year follow-up, mortality rates were highest in patients with low CPI (23.4%) and low TPRI (22.2%).

Conclusions

Non-invasive assessment of patients’ response to HD provides relevant hemodynamic information that exceeds that provided by currently used BP measurements. Use of these online analyses could potentially improve the safety and performance standards of dialysis by guiding appropriate interventions, particularly in responding to hypertension and hypotension.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1542-4) contains supplementary material, which is available to authorized users.

A Phase 1 Randomized Study of Single Intravenous Infusions of the Novel Nitroxyl Donor BMS-986231 in Healthy Volunteers

Nitroxyl (HNO) is a reactive nitrogen molecule that has potential therapeutic benefits for patients with acute heart failure. The results of the first‐in‐human study for BMS‐986231, a novel HNO donor, are reported. The aim of this sequential cohort study was to evaluate the safety, tolerability, and pharmacokinetic profile of BMS‐986231 after 24‐ and 48‐hour intravenous infusions in healthy volunteers. Eighty subjects were randomized and dosed. Seven cohorts (stratum A) received BMS‐986231 0.1, 0.33, 1, 3, 5, 10, and 15 μg/kg/min or placebo, infused over 24 hours. An additional cohort (stratum B) received 10 μg/kg/min or placebo, infused over 48 hours. Adverse events (AEs) were reported for 30 days after completion of infusion. Blood/urine samples were collected at regular intervals; other parameters (blood pressure, heart rate/rhythm, cardiac index) were also assessed. Headaches were the most commonly reported drug‐related AE (48%) in those who received BMS‐986231, although their severity was reduced by hydration. No other significant drug‐related AEs were noted. BMS‐986231 was associated with dose‐dependent and well‐tolerated reductions in systolic and diastolic blood pressure versus baseline; cardiac index, as measured noninvasively, was increased. BMS‐986231 had no clinically significant effect on heart rate/rhythm or laboratory parameters. Its mean elimination half‐life was 0.7‐2.5 hours. BMS‐986231 was safe and well‐tolerated for up to 24 hours (15 μg/kg/min) or 48 hours (10 μg/kg/min), with a favorable hemodynamic profile observed. Ongoing studies continue to evaluate the potential benefit of BMS‐986231 in patients with acute heart failure.

The value of non-invasive measurement of cardiac output and total peripheral resistance to categorize significant changes of intradialytic blood pressure: a prospective study

Background

Blood pressure (BP) is currently the main hemodynamic parameter used to assess the influence of fluid removal during hemodialysis session. Since BP is dependent on cardiac output (CO) and total peripheral resistance (TPRI), investigating these parameters may help to better understand the influence of fluid removal on patient’s hemodynamics. We used a novel non-invasive whole-body bio-impedance cardiography device, recently validated in hemodialysis patients, to examine mechanisms of intradialytic hemodynamics in a Chinese dialysis population.

Methods

Chronic hemodialysis patients in Sichuan Provincial People’s Hospital were enrolled. Demographic data and dialysis prescriptions were collected. Hemodynamic measurements were made pre-treatment, every 20 min during treatment and immediately after treatment in each random dialysis session. These included blood pressure, cardiac index (CI), total peripheral resistance (TPRI) and cardiac power index (CPI). Patients were divided into 5 hemodynamic groups as per their major hemodynamic response to fluid removal: low CPI, low TPRI, high TPRI, High CPI and those with normal hemodynamics.

Results

Twenty-seven patients were enrolled, with 12 (44.4%) males. The average age was 65 ± 12 y. The average body mass index (BMI) was 23.7 ± 3.9 kg/m2. 12 (44.4%) patients were diabetic. Three hundred twenty-four hemodynamic measurements were made. Weight, BMI, total fluid removal, pretreatment systolic BP, CI, TPRI and CI differed significantly among the 5 hemodynamic groups.11.1% of patients had low CPI, 25.9% had low TPRI, 18.5% had high CPI, 3.7% had high TPRI and 40.7% had normal hemodynamics. Hemodynamic differences among the 5 subgroups were significant.

Conclusion

This technology provides multi-dimensional insight into intradialytic hemodynamic parameters, which may be more informative than blood pressure only. Using hemodynamic parameters to describe patients’ status is more specific and accurate, and could help to work out specific and effective therapeutic actions according to underlying abnormalities.

Maternal cardiovascular hemodynamics in normotensive versus preeclamptic pregnancies: a prospective longitudinal study using a noninvasive cardiac system (NICaS™)

BACKGROUND

Preeclampsia is among the most common medical complications of pregnancy. The clinical utility of invasive hemodynamic monitoring in preeclampsia (e.g., Swan-Ganz catheter) is controversial. Thoracic impedance cardiography (TIC) and Doppler echocardiography are noninvasive techniques but they both have important limitations. NICaS™ (NI Medical, PetachTikva, Israel) is a noninvasive cardiac system for determining cardiac output (CO) that utilizes regional impedance cardiography (RIC) by noninvasively measuring the impedance signal in the periphery. It outperformed any other impedance cardiographic technology and was twice as accurate as TIC.

METHODS

We used the NICaS™ system to compare the hemodynamic parameters of women with severe preeclampsia (PET group, n = 17) to a cohort of healthy normotensive pregnant women with a singleton pregnancy at term (control group, n = 62) (1/2015-6/2015). Heart rate (HR), stroke volume (SV), CO, total peripheral resistance (TPR) and mean arterial pressure (MAP) were measured 15-30 min before CS initiation, immediately after administering spinal anesthesia, immediately after delivery of the fetus and placenta, at the abdominal fascia closure and within 24-36 and 48-72 h postpartum.

RESULTS

The COs before and during the CS were significantly higher in the control group compared to the PET group (P < .05), but reached equivalent values within 24-36 h postpartum. CO peaked at delivery of the newborn and the placenta and started to decline afterwards in both groups. The MAP and TPR values were significantly higher in the PET group at all points of assessment except at 48-72 h postpartum when it was still significantly higher for MAP while the TPR only exhibited a higher trend but not statistically significant. The NICaS™ device noninvasively demonstrated low CO and high TPR profiles in the PET group compared to controls.

CONCLUSIONS

The immediate postpartum period is accompanied by the most dramatic hemodynamic changes and fluid shifts, during which the parturient should be closely monitored. The NICaS™ device may help the clinician to customize the most optimal management for individual parturients. Our findings require validation by further studies on larger samples.

Perioperative noninvasive cardiac output monitoring in parturients undergoing cesarean delivery with spinal anesthesia and prophylactic phenylephrine drip: a prospective observational cohort study

Introduction: Spinal anesthesia for cesarean delivery is associated with high incidence of hypotension and is most often prevented by a prophylactic phenylephrine infusion (PPI). In this study, we aimed to identify maternal hemodynamic changes both intraoperatively and postoperatively with the use of the NICaS noninvasive cardiac output monitor in healthy singleton parturients undergoing cesarean delivery (CD) with spinal anesthesia and PPI. Methods: Healthy term women undergoing spinal anesthesia for singleton CD were enrolled. The following data were collected - cardiac output (CO), mean arterial pressure (MAP), stroke volume (SV), and total peripheral resistance (TPR). Measurements were measured at five time points: (1) before arrival in OR, (2) after spinal anesthesia with pi, (3) after delivery of baby and beginning of oxytocin infusion, (4) in post anesthesia care room (5) 24 hours postoperatively, and (6) 48 hours postoperatively. All parturients received standardized spinal solution consisting of 12 mg hyperbaric, 20 µg fentanyl, and 100-µg preservative-free morphine. PPI was titrated to preserve blood pressure to 20% of baseline and stopped at the end of surgery. Oxytocin was administered as a continuous infusion (20-units/1000 cc Ringer lactate) at a rate of 100 cc/h. Results: One hundred thirty-seven women completed the study. Average age was 34.9 ± 5.7 and average BMI was 30.1 ± 5.1. One hour after delivery in the post anesthesia care unit (PACU), there were significant decreases in stroke volume, heart rate, blood pressure, and CO with a concomitant increase in TPR. Within 48 hours the TPR decreased, and CO and stroke volume increased. Conclusions: Significant hemodynamic changes were documented at all time points both intraoperatively and postoperatively with the most significant changes occurring 1 hour postoperatively. Further studies need to be performed to discover hemodynamic changes of spinal anesthesia and PPI in different parturient populations.

Maternal hemodynamics in late gestation and immediate postpartum in singletons vs. twin pregnancies

PURPOSE

Differences in hemodynamic changes during a cesarean section (CS) between twin and singleton pregnancies are poorly defined. The Non-Invasive Cardiac System (NICaS) is an impedance device that measures cardiac output (CO) and its derivatives. We compared maternal cardiac parameters using NICaS™ in singleton and twins before and during delivery, as well at the early puerperium in healthy women undergoing CS at term.

METHODS

This prospective longitudinal study included women with twin (n = 27) or singleton pregnancies (n = 62) whose hemodynamic parameters were assessed by NICaS before an elective CS, after spinal anesthesia, immediately after delivery, after fascia closure, and within 24-36 and 48-72 h postpartum.

RESULTS

By 24-36 h postpartum, the mean arterial pressure and the total peripheral resistance equaled preoperative values in both groups. The CO increased throughout the CS and peaked immediately after delivery in the singleton group (P < 0.0001), after which it abruptly began to decline until reaching a nadir 24-36 h after delivery (P < 0.0001), while it remained steady throughout the CS and then dropped until 24-36 h after delivery in the twin group (P < 0.05). None of the studied parameters differed significantly between the groups for the 24-36 and 48-72 h postpartum measurements.

CONCLUSIONS

Hemodynamic parameters immediately before, during and shortly after CS in singleton and twin pregnancies are equivalent. Further evaluations of the value of NICaS™ in assessing cardiovascular-related pregnancy complications are warranted.

Comparison of stroke volume measurements during hemodialysis using bioimpedance cardiography and echocardiography

BACKGROUND

Fluid management remains a major challenge of hemodialysis (HD) care, with serious implications for morbidity and mortality. Intradialytic fluid management is typically guided by blood pressure, an indirect resultant of hemodynamics status. Direct measurements of hemodynamic parameters may improve cardiovascular outcomes by providing rational bases for intervention. We compare stroke volume (SV) measurements using a noninvasive, regional biompedance cardiography device (NiCaS) with Doppler echocardiography (Echo) in HD setting.

METHODS

Stroke volumes were simultaneously measured using the devices in 17 patients receiving maintenance HD. Measurements were made during 2 weekly HD treatments, and twice within each HD treatment during the first and last hour of each treatment, for a total of 64 SV measurements. Agreement between devices was assessed using linear regression, a Pearson's correlation coefficient, and a Bland-Altman plot all adjusted for repeated measures within patients.

RESULTS

Echo and NiCaS SV mean and 95% CIs were 58.0 (50.1, 65.8) and 56.7 (49.4, 64.0) mL, respectively. NiCaS SV correlated strongly with Echo SV during the first and last hours of treatments (r = 0.93, P < 0.001 and r = 0.92, P < 0.001, respectively). Linear regression of NiCaS on Echo showed a slope of 0.97, 95% CI (0.91, 1.02) which did not differ from 1, P = 0.20. A Bland-Altman plot and 4-Quadrant plot confirmed that the 2 methods produced comparable measurements.

CONCLUSION

NiCaS SV measurements are similar to and strongly correlated with Echo SV measurements. This suggests that noninvasive NiCaS technology may be a practical method for measuring SV during HD.

A Phase 2a dose-escalation study of the safety, tolerability, pharmacokinetics and haemodynamic effects of BMS-986231 in hospitalized patients with heart failure with reduced ejection fraction

Aims

This study was designed to evaluate the safety, tolerability and haemodynamic effects of BMS‐986231, a novel second‐generation nitroxyl donor with potential inotropic, lusitropic and vasodilatory effects in patients hospitalized with decompensated heart failure and reduced ejection fraction (HFrEF).

Methods and results

Forty‐six patients hospitalized with decompensated HFrEF were enrolled into four sequential dose‐escalation cohorts in this double‐blind, randomized, placebo‐controlled Phase 2a study. Patients with baseline pulmonary capillary wedge pressure (PCWP) of ≥20 mmHg and a cardiac index of ≤2.5 L/min/m² received one 6‐h i.v. infusion of BMS‐986231 (at 3, 5, 7 or 12 µg/kg/min) or placebo. BMS‐986231 produced rapid and sustained reductions in PCWP, as well as consistent reductions in time‐averaged pulmonary arterial systolic pressure, pulmonary arterial diastolic pressure and right atrial pressure. BMS‐986231 increased non‐invasively measured time‐averaged stroke volume index, cardiac index and cardiac power index values, and decreased total peripheral vascular resistance. There was no evidence of increased heart rate, drug‐related arrhythmia or symptomatic hypotension with BMS‐986231. Analyses of adverse events throughout the 30‐day follow‐up did not identify any toxicities specific to BMS‐986231, with the potential exception of infrequent mild‐to‐moderate headaches during infusion. There were no treatment‐related serious adverse events.

Conclusions

BMS‐986231 demonstrated a favourable safety and haemodynamic profile in patients hospitalized with advanced heart failure. Based on preclinical data and these study's findings, it is possible that the haemodynamic benefits may be mediated by inotropic and/or lusitropic as well as vasodilatory effects. The therapeutic potential of BMS‐986231 should be further assessed in patients with heart failure.

Cardiac hemodynamics before, during and after elective cesarean section under spinal anesthesia in low-risk women

OBJECTIVE

The aim of this study was to describe maternal central hemodynamic parameters before and during delivery as well at the early puerperium in healthy women undergoing elective cesarean section (CS) at term.

STUDY DESIGN

The noninvasive Cardiac System (NICaS, NI Medical, Petah-Tikva, Israel) is a regional impedance device that measures cardiac output (CO) and its derivatives with a good correlation with the gold standard Swan-Ganz catheter. We performed a prospective longitudinal study of healthy women with a singleton pregnancy at term. Maternal hemodynamic parameters were assessed by the NICaS at six time points: a few minutes before undergoing an elective CS, immediately after receiving spinal anesthesia, immediately after delivery of the fetus and placenta, after abdominal fascia closure, and within 24 to 36 and 48 to 72 h postpartum.

RESULT

Sixty-one consenting women were recruited during the study period (January 2015 to June 2015). Baseline (pre-CS) mean arterial pressure (MAP) was 87.7±7.9 mm Hg, baseline CO was 7.5±1.7 l per min and baseline total peripheral resistance (TPR) was 994±301 dyne × s per cm⁵. After spinal anesthesia CO significantly increased by 13%, no significant changes were observed in MAP or TPR. Immediately after delivery, a nadir for all parameters was reached: MAP and TPR were significantly reduced by 8% and 26%, respectively (comparing to pre-CS), and CO further increased by 9% (24% comparing to pre-CS). After fascia closure, partial recoveries of all parameters were observed. Twenty-four to thirty-six hours postpartum MAP returned to pre-CS values, while CO and TPR reached -9% and +11% comparing to baseline, respectively. None of the parameters differed significantly between 24 to 36 and 48 to 72 h postpartum.

CONCLUSION

Significant hemodynamic changes (reduction of TPR and increase of CO) take place at the time of delivery of fetus and placenta. Knowledge of normal hemodynamic values using a reliable noninvasive technique during various stages of pregnancy and the postpartum period is feasible, and might assist clinicians in assessing the level of patient deviation from expected cardiac performance, especially in high-risk women.

Perioperative sequential monitoring of hemodynamic parameters in patients with pheochromocytoma using the Non-Invasive Cardiac System (NICaS)

Surgical treatment of pheochromocytoma is associated with a high risk of hemodynamic instability. To reduce the risk of perioperative complications, adequate medical treatment to normalize blood pressure and restore blood volume is required. Accurate evaluation of the circulating blood volume (CBV) in perioperative patients with pheochromocytoma is clinically important. In the present study, we adopted whole-body bioimpedance monitoring technique using the Non-Invasive Cardiac System (NICaS), which can non-invasively measure cardiac output (CO) values. NICaS-derived CO values were evaluated in eight preoperative patients with pheochromocytoma and were compared with simultaneous CBV values measured by a conventional indicator dilution method using (131)I-labeled human serum albumin. In these patients with pheochromocytoma, the NICaS-derived CO values were significantly correlated with the CBV values measured by (131)I-labeled human serum albumin (4.86 ± 1.05 L/min vs 4.79 ± 1.02 L; r = 0.906; P = 0.002). Sequential NICaS-derived CO values confirmed that CBV increased after preoperative treatment with an α-blocker, with or without volume loading. The results of this study indicate that NICaS can be used to accurately and non-invasively evaluate the hemodynamic status. By sequential monitoring of NICaS-derived CO values, we are able to confirm whether adequate CBV in a patient with pheochromocytoma is obtained by preoperative medical treatment with α-blockers or volume loading, to avoid perioperative complications.

Evaluation of changes in cardiac output from the electrical impedance waveform in the forearm

We tested the validity of regional impedance cardiography (RIC) for measuring changes in both cardiac output and stroke volume by comparing the values with a 2D ultrasound technique in response to the breath-hold manipulation. Among 13 subjects, changes in the maximum amplitude of the regional impedance waveform from the forearm conformed to those in stroke volume (r = 0.86, p < 0.001) and cardiac output (r = 0.76, p < 0.003) measured with the ultrasound technique in baseline and immediately after a 30 s breath-hold maneuver. We also found that the per cent change in cardiac output (r = 0.73, p < 0.005) and the per cent change in stroke volume (r = 0.84, p < 0.0003) by the echocardiography were both positively correlated with the per cent change in the peak impedance amplitude. In addition, both the change and the per cent change in the mean area under the impedance curve were consistent with those in the stroke volume, respectively. Accordingly, the regional electrical impedance waveform from lower limbs may be helpful in providing a non-invasive and continuous assessment of left ventricular output, especially during cardiac procedures.