Evaluation of Electrical Cardiometry to Assess Fluid Responsiveness in Patients with Acute Circulatory Failure: A Comparative Study with Transthoracic Echocardiography

Aim

Acute circulatory failure is commonly encountered in critically ill patients, that requires fluid administration as the first line of treatment. However, only 50% of patients are fluid-responsive. Identification of fluid responders is essential to avoid the harmful effects of overzealous fluid therapy. Electrical cardiometry (EC) is a non-invasive bedside tool and has proven to be as good as transthoracic echocardiography (TTE) to track changes in cardiac output. We aimed to look for an agreement between EC and TTE for tracking changes in cardiac output in adult patients with acute circulatory failure before and after the passive leg-raising maneuver.

Materials and methods

Prospective comparative study, conducted at a Tertiary Care Teaching Hospital.

Results

We recruited 125 patients with acute circulatory failure and found 42.4% (53 out of 125) to be fluid-responsive. The Bland-Altman plot analysis showed a mean difference of 2.08 L/min between EC and TTE, with a precision of 3.8 L/min. The limits of agreement (defined as bias ± 1.96SD), were -1.7 L/min and 5.8 L/min, respectively. The percentage of error between EC and TTE was 56% with acceptable limits of 30%.

Conclusion

The percentage error beyond the acceptable limit suggests the non-interchangeability of the two techniques. More studies with larger sample sizes are required to establish the interchangeability of EC with TTE for tracking changes in cardiac output in critically ill patients with acute circulatory failure.

How to cite this article

Sharma S, Ramachandran R, Rewari V, Trikha A. Evaluation of Electrical Cardiometry to Assess Fluid Responsiveness in Patients with Acute Circulatory Failure: A Comparative Study with Transthoracic Echocardiography. Indian J Crit Care Med 2024;28(7):650-656.

Cardiovascular Diseases Diagnosis by Impedance Cardiography

Cardiovascular disease (CVD) represents the leading cause of mortality worldwide. In order to diagnose CVDs, there are a range of detection methods, among them, the impedance cardiography technique (ICG). It is a non-invasive and low-cost method. In this paper, we highlight recent advances and developments of the CDVs diagnosis mainly by the ICG method. We considered papers published during the last five years (from 2017 until 2022). Based on this study, we expressed the need for an ICG database for the different CDVs.

Electrocardiometry for Hemodynamic Categorization and Assessment of Fluid Responsiveness in Pediatric Septic Shock: A Pilot Observational Study

Aim

To evaluate the utility of noninvasive electrocardiometry (ICON®) for hemodynamic categorization and assessment of fluid responsiveness in pediatric septic shock.

Materials and methods

Pilot prospective observational study in a 12-bedded tertiary pediatric intensive care unit (PICU) in children aged between 2 months and 16 years with unresolved septic shock after a 20 mL/kg fluid bolus. Those with cardiac index (CI) <3.3 L/min/m² and systemic vascular resistance index (SVRI) >1600 dyn sec/cm⁵/m² were classified as vasoconstrictive shock–electrocardiometry (VCEC) and those with CI >5.5 L/min/m² and SVRI <1000 dyn sec/cm⁵/m² as vasodilated shock–electrocardiometry (VDEC). Fluid responsiveness was defined as a 10% increase in CI with a 20 mL/kg fluid bolus. Sepsis-induced myocardial dysfunction (SMD) was diagnosed on echocardiography. Outcomes studied included clinical shock resolution, length of PICU stay, and mortality.

Results

Thirty children were enrolled over 6 months with a median (interquartile range) age and pediatric risk of mortality (PRISM) III score of 87(21,108) months and 6.75(1.5,8.25), respectively; 14(46.6%) were boys and 4(13.3%) died. Clinically, 19(63.3%) children had cold shock and 11(36.7%) had warm shock; however, 16(53.3%) children had VDEC (including five with clinical cold shock) and 14(46.7%) had VCEC using electrocardiometry. Fluid responsiveness was seen in 16(53.3%) children, 10 in the VCEC group and 6 in the VDEC group. In the VCEC group, the responders had a significant rise in CI and a fall in SVRI, while the responders in the VDEC group had a significant rise in CI and SVRI. Fluid responders, compared to nonresponders, had a significantly higher stroke volume variation (SVV) before fluid bolus (24.1 ± 5.2% vs. 18.2 ± 3.5%, p < 0.001) and a higher reduction in SVV after fluid bolus (10.0 ± 2.8% vs. 6.0 ± 4.5%, p = 0.006), higher lactate clearance (p = 0.03) and lower vasoactive-inotropic score (p = 0.04) at 6 hours, higher percentage of clinical shock resolution at 6 (p = 0.01) and 12 hours (p = 0.01), and lesser mortality (p = 0.002). Five (16.6%) children with VCEC had SMD and were less fluid responsive (p = 0.04) with higher mortality (p = 0.01) compared to those without SMD.

Conclusions and clinical significance

Continuous, noninvasive hemodynamic monitoring using electrocardiometry permits hemodynamic categorization and assessment of fluid responsiveness in pediatric septic shock. This may provide real-time guidance for optimal interventions, and thus, improve the outcomes.

How to cite this article

Rao SS, Reddy M, Lalitha AV, Ghosh S. Electrocardiometry for Hemodynamic Categorization and Assessment of Fluid Responsiveness in Pediatric Septic Shock: A Pilot Observational Study. Indian J Crit Care Med 2021;25(2):185–192.

Electrocardiometry Fluid Responsiveness in Pediatric Septic Shock

Hemodynamic monitoring and categorization of patients based on fluid responsiveness is the key to decisions prompting the use of fluids and vasoactive agents in septic shock. Distinguishing patients who are going to benefit from fluids from those who will not is of paramount importance as large amounts of fluids used conventionally based on surviving sepsis guidelines may be detrimental. Noninvasive monitoring techniques for the assessment of various cardiovascular parameters are increasingly accepted as the current medical practice. Electrical cardiometry (EC) is one such method for the determination of stroke volume, cardiac output (CO), and other hemodynamic parameters and is based on changes in electrical conductivity within the thorax. It has been validated against gold standard methods such as thermodilution [Malik V, Subramanian A, Chauhan S, et al. World J 2014;4(7):101-108] and is being used more often as a point-of-care noninvasive technique for hemodynamic monitoring. EC is Food and Drug Administration approved and validated for use in neonates, children, and adults. A meta-analysis in 2016, including 20 studies and 624 patients comparing the accuracy of CO measurement by using EC with other noninvasive technologies, demonstrated that EC was the device that offered the most correct measurements. The article in the current issue of IJCCM by Rao et al. (2020) has extended the use of EC to categorize pediatric patients with septic shock into vasodilated and vasoconstricted states based on systemic vascular resistance and correlate the categorization clinically. The authors also studied the changes in hemodynamic parameters after an isotonic fluid bolus of 20 mL/kg was administered. This is a pilot prospective observational study of 30 patients, which has given an insight into physiological rearrangements following fluid administration in patients with septic shock. How to cite this article: Gupta D, Dhingra. Electrocardiometry Fluid Responsiveness in Pediatric Septic Shock. Indian J Crit Care Med 2021;25(2):123-125.

The accuracy of electrical cardiometry for the noninvasive determination of cardiac output before and after lung surgeries compared to transthoracic echocardiography

Background:

The anatomical changes associated with lung surgeries may decrease cardiac output and heart function. Therefore, monitoring of cardiac output (CO) is of significant value in these patients for clinical decision-making.

Objective:

This study is to evaluate the reliability of electrical cardiometry (EC) for the noninvasive continuous determination of CO after lobectomy or pneumonectomy compared to transthoracic echocardiography (TTE).

Patients and Methods:

This study was carried out on 60 patients, age ≥18 years scheduled for elective lung surgery (lobectomy or pneumonectomy). All patients underwent simultaneous measurement by EC using the ICON_ device and by TTE by measuring left ventricle outflow tract diameter (LVOT) and velocity time integral (VTI). Heart rate (HR), systolic and diastolic blood pressure (SBP and DBP), stroke volume (SV), stroke volume index (SVI), CO, and cardiac index (CI) were measured 1 day before the surgery and 7 days after the surgery.

Results:

There was no significant difference between TTE and EC regarding preoperative and postoperative HR, SV, SVI, CO, and CI. There was a strong positive correlation between TTE and EC as regard preoperative and postoperative HR, SV, SVI, CO, and CI. Bland and Altman analysis showed low bias with accepted limits of agreement of HR, SV, SVI, CO, and CI. Postoperative readings showed a significant increase in HR and a significant decrease in SV and CO (either by TTE or EC), SBP, and DBP as compared to preoperative reading.

Conclusion:

Compared to the TTE, EC provides accurate and reliable CO, SV, and HR measurements before and even after lung surgeries.

The influence of the infusion of ephedrine and phenylephrine on the hemodynamic stability after subarachnoid anesthesia in senior adults - a controlled randomized trial

Background

We studied the influence of ephedrine or phenylephrine infusion administered immediately after spinal anesthesia (SA) on hemodynamics in elderly orthopedic patients.

Methods

A prospective, randomized, double-blind, placebo-controlled study.

After a subarachnoid injection of 15 mg of levobupivacaine, the participants received an infusion of either ephedrine 20 mg (E group), phenylephrine 250 mcg (P group) or saline (C group) within 30 min. We measured blood pressure, cardiac index (CI) and heart rate (HR) from 15 min before to 30 min after SA.

Results

Seventy patients were included in the final analysis. At the end of measurements, mean arterial pressure (MAP) decreased significantly after SA in comparison to the baseline value in the C group but was maintained in the P and E group, with no significant differences between the groups. CI decreased after SA in the C group, was maintained in the P group, and increased significantly in the E group with significant differences between the C and E group (p = 0.049) also between the P and E (p = 0.01) group at the end of measurements. HR decreased significantly after SA in the C and P group but was maintained in the E group, with significant differences between the P and E group (p = 0.033) at the end of measurements.

Conclusions

Hemodynamic changes after SA in elderly orthopedic patients can be prevented by an immediate infusion of phenylephrine or ephedrine. In addition to maintaining blood pressure, the ephedrine infusion also maintains HR and increases CI after SA.

Trial registration

ISRCTN registry with registration number ISRCTN44377602, retrospectively registered on 15 June 2017.

Predictive and prognostic roles of electrical cardiometry in noninvasive assessments of community-acquired pneumonia patients with dyspnoea

Background:

Thoracic impedance monitoring able to detect pneumonia in the very early phase of emerging infiltration prior the patient developed remarkable clinical symptoms. However, no studies have yet been conducted on the usefulness of predicting pneumonia patient outcomes with parameters from electrical cardiometry.

Objective:

In the present study, we evaluated whether parameters measured by electrical cardiometry can predict clinical outcomes including mortality and length of hospital stay in patients with community-acquired pneumonia in the emergency department.

Methods:

Demographic, clinical and laboratory data were collected from enrolled patient. Electrical cardiometry monitoring was done with a portable electrical cardiometry device connected to the body surface sensor. The continuous data from electrical cardiometry were recorded, and parameters were stored on the electrical cardiometry device automatically and then the data were downloaded for further analysis.

Results:

Thoracic fluid content has shown to be significantly higher in the intensive care unit admission group and in the death group. Expired patients had higher value of thoracic fluid content at emergency department admission. From a receiver operating characteristics curve analysis, thoracic fluid content presented fair AUC values of 0.72 (95% confidence interval, 0.71–0.74) and 0.73 (0.62–0.82) for prediction of 28-day mortality and intensive care unit admission. Arterial partial pressure of oxygen (PaO2), the ratio of arterial partial pressure of oxygen to inspired oxygen fraction (PaO2/FiO2 ratio) also showed excellent AUC value for prediction of mortality and intensive care unit admission.

Conclusion:

Electrical cardiometry monitoring indicated new possibility to anticipate prognosis of community-acquired pneumonia patient. Increased thoracic fluid content value would relate worse outcome of the patient like mortality and intensive care unit admission. Electrical cardiometry monitoring allows real-time measurements of thoracic fluid content without restraining the patient or invasive catheters.

Accuracy and precision of non-invasive cardiac output monitoring by electrical cardiometry: a systematic review and meta-analysis

Cardiac output monitoring is used in critically ill and high-risk surgical patients. Intermittent pulmonary artery thermodilution and transpulmonary thermodilution, considered the gold standard, are invasive and linked to complications. Therefore, many non-invasive cardiac output devices have been developed and studied. One of those is electrical cardiometry. The results of validation studies are conflicting, which emphasize the need for definitive validation of accuracy and precision. We performed a database search of PubMed, Embase, Web of Science and the Cochrane Library of Clinical Trials to identify studies comparing cardiac output measurement by electrical cardiometry and a reference method. Pooled bias, limits of agreement (LoA) and mean percentage error (MPE) were calculated using a random-effects model. A pooled MPE of less than 30% was considered clinically acceptable. A total of 13 studies in adults (620 patients) and 11 studies in pediatrics (603 patients) were included. For adults, pooled bias was 0.03 L min^-1 [95% CI - 0.23; 0.29], LoA - 2.78 to 2.84 L min^-1 and MPE 48.0%. For pediatrics, pooled bias was - 0.02 L min^-1 [95% CI - 0.09; 0.05], LoA - 1.22 to 1.18 L min^-1 and MPE 42.0%. Inter-study heterogeneity was high for both adults (I² = 93%, p < 0.0001) and pediatrics (I² = 86%, p < 0.0001). Despite the low bias for both adults and pediatrics, the MPE was not clinically acceptable. Electrical cardiometry cannot replace thermodilution and transthoracic echocardiography for the measurement of absolute cardiac output values. Future research should explore it's clinical use and indications.

Oral thyroxin supplementation in infants undergoing cardiac surgery: A double-blind placebo-controlled randomized clinical trial

BACKGROUND

Decreases in serum total thyroxin and total triiodothyronine occurs after cardiopulmonary bypass, and is reflected as poor immediate outcome. We studied effects of oral thyroxin supplementation in infants who underwent open-heart surgery.

METHODS

In this prospective study, 100 patients were randomized into 2 groups: 50 in the thyroxin group (TH) and 50 in the placebo group (PL). Patients in the TH group received oral thyroxin (5 μg/kg) 12 hours before surgery and once daily for the remainder of their intensive care unit (ICU) stay. Data on intraoperative and postoperative variables were recorded. Cardiac index (CI) was measured. Perioperative serum thyroid hormone levels and serum interleukin-6 and tumor necrosis factor-α were measured. Secondary analysis was performed by dividing patients into simple and complex subcategories.

RESULTS

Results of the primary analysis indicated a higher CI in the TH compared with the PL. In the complex category, the mean duration of mechanical ventilation was 3.85 ± 0.93 and 4.66 ± 1.55 days in the TH and PL, respectively (P = .001). Mean ICU stay was 6.79 ± 2.26 and 8.33 ± 3.09 days (P = .03), and mean hospital stay was 15.70 ± 4.77 and 18.90 ± 4.48 days (P = .01) in the TH and PL, respectively. There were no significant differences between the TH and the PL in the simple category. CI was higher in the TH at all time points (P = .004). The average therapeutic intervention scoring system scores for the first 2 days were higher in the PL in the complex category.

CONCLUSIONS

Oral thyroxin supplementation improves the CI and reduces the inotropic requirement. In addition, it reduces the duration of mechanical ventilation, ICU and hospital stay, and therapeutic intervention scoring system in infants after surgery for complex congenital heart defects.

Continuous infusion of furosemide versus intermittent boluses in acute decompensated heart failure: Effect on thoracic fluid content

INTRODUCTION

The administration of loop diuretics in the management of acute decompensated heart failure (ADHF) whether IV boluses or continuous infusion is still controversial. We intended to evaluate differences between the two administration routes on the thoracic fluid content (TFC) and the renal functions.

METHODS

Sixty patients with ADHF admitted to the critical care medicine department (Cairo University, Egypt) were initially enrolled in the study. Twenty patients were excluded due to EF > 40%, myocardial infarction within 30 days, and baseline serum creatinine level > 4.0 mg/dL. Furosemide (120 mg/day) was given to the remaining 40 pts who continued the study after 1:1 randomization to either continuous infusion (group-I, 20 pts) or three equal intermittent daily doses (group-II, 20 pts). Subsequent dose titration was allowed after 24 h, but not earlier, according to patient's response. No other diuretic medications were allowed. All patients were daily evaluated for NYHA class, urine output, TFC, body weight, serum K+, and renal chemistry.

RESULTS

The median age (Q1-Q3) was 54.5 (43.8-63.8) years old with 24 (60%) males. Apart from TFC which was significantly higher in group-I, the admission demographic, clinical, laboratory and co-morbid conditions were similar in both groups. There was statistically insignificant tendency for increased urine output during the 1st and 2nd days in group-I compared to group-II (p = .08). The body weight was decreased during the 1st day by 2 (1.5-2.5) kg in group-I compared to 1.5 (1-2) kg in group-II, (p = .03). These changes became insignificant during the 2nd day (p = .4). The decrease of TFC was significantly higher in group-I than in group-II [10 (6.3-14.5) vs 7 (3.3-9.8) kΩ-1 during the first day and 8 (6-11) vs 6 (3.3-8.5) kΩ-1 during the second day in groups-I&II respectively, P = .02 for both]. There was similar NYHA class improvement in both groups (p = .7). The serum creatinine was increased by 0.2 (0.1-0.5) vs 0 (-0.1 to 0.2) mg% and the CrCl was decreased by 7.4 (4.5-12.3) vs 3.1 (0.2-8.8) ml/min in groups-I&II respectively (p = .009 and .02 respectively).

CONCLUSIONS

We concluded that continuous furosemide infusion in ADHF might cause greater weight loss and more decrease in TFC with no symptomatic improvement and possibly with more nephrotoxic effect.

Prediction of Future Overt Pulmonary Hypertension by 6-Min Walk Stress Echocardiography in Patients With Connective Tissue Disease

BACKGROUND

Early detection of pulmonary hypertension (PH) in connective tissue disease (CTD) is crucial to ensuring that patients receive timely treatment for this progressive disease. Exercise stress tests have been used to screen patients in an attempt to identify early-stage PH. Recent studies have described abnormal mean pulmonary artery pressure (mPAP)-cardiac output (Q) responses as having the potential to assess the disease state.

OBJECTIVES

This study hypothesized that pulmonary circulation pressure-flow relationships obtained by 6-min walk (6MW) stress echocardiography would better delineate differential progression of PH and predict development of PH during follow-up.

METHODS

We prospectively performed 6MW stress echocardiographic studies in 78 CTD patients (age 58 ± 12 years; 9% male) at baseline and follow-up. All patients underwent yearly echocardiographic follow-up studies for up to 5 years.

RESULTS

During a median period of 32 months (range: 15 to 62 months), 16 patients reached the clinical endpoint of development of PH and none died during follow-up. PH was confirmed by right heart catheterization in all 16 patients (mPAP ≥25 mm Hg and pulmonary capillary wedge pressure ≤15 mm Hg). In a Cox proportional-hazards survival model, 6MW distance (hazard ratio [HR]: 0.99; p = 0.010), early diastolic tricuspid annulus motion velocity (HR: 0.79; p = 0.025), and ΔmPAP/ΔQ by 6MW stress (HR: 1.10; p = 0.005) were associated with development of PH. In sequential Cox models, a model on the basis of 6MW distance (chi-square, 6.6) was improved by ΔmPAP/ΔQ (chi-square: 14.4; p = 0.019). Using a receiver-operating characteristic curve, we found that the best cutoff value of ΔmPAP/ΔQ for predicting development of pulmonary hypertension was >3.3 mm Hg/l/min.

CONCLUSIONS

The 6MW stress echocardiography noninvasively provides an incremental prognostic value of PH development in CTD. This is a single-center prospective cohort study. Larger multicenter studies are warranted to confirm this result.