Pressure recording analytical method and bioreactance for stroke volume index monitoring during pediatric cardiac surgery

Contemporary Trends and Risk Factors of Hemodynamic and Myocardial Mechanics Derived by the Pressure Recording Analytical Method After Pediatric Cardiopulmonary Bypass

Objective: Adverse factors of postoperative hemodynamic and myocardial performance remain largely unexplored in children with congenital heart disease following cardiopulmonary bypass due to technical limitations. Pressure recording analytical method (PRAM) is a continuous hemodynamic and myocardial performance monitoring technique based on beat-to-beat arterial pressure waveform. Using PRAM, we examined the temporal trends and adverse factors, in clinical management, of these performances.

Methods: We monitored blood pressure, cardiac index, cardiac cycle efficiency (CCE), dP/dT_max, and systematic vascular resistance index in 91 children (aged 186 ± 256 days) during their first 48 h after cardiopulmonary bypass. Above parameters, inotropic and vasoactive drug dosages, and serum lactate were recorded 3-hourly. NT-proBNP was measured daily.

Results: CCE and dP/dT_max gradually increased (Ps < 0.0001), while systematic vascular resistance index, diastolic blood pressure and inotrope dosages decreased (Ps < 0.0001) over time. Cardiac index, systolic blood pressure, and heart rate did not change significantly (Ps ≥ 0.231). Patients undergoing deep hypothermic circulatory arrest had significantly higher heart rate and lower CCE (Ps ≤ 0.006) over time. Multivariate analyses indicated that epinephrine dose significantly correlated with systolic blood pressure, cardiac index, CCE, and dP/dT_max after polynomial transformation, with the peak ranging from 0.075 to 0.097.

Conclusions: Systemic hemodynamic and myocardial performance gradually improved in the first 48 h after cardiopulmonary bypass without the “classic” nadir at 9–12 h. Deep hypothermic circulatory arrest and higher epinephrine doses were adversely associated with these performances. CCE, rather than cardiac index or other common-used parameters, was the most sensitive and consistent indicator.

Veno-arterial CO2 difference and cardiac index in children after cardiac surgery

Veno-arterial CO2 difference has been considered as a marker of low cardiac output. This study aimed to evaluate the correlation between veno-arterial CO2 difference and cardiac index estimated by MostCareTM in children after cardiac surgery and its association with other indirect perfusion parameters and the complex clinical course (vasoactive inotropic score above 15 or length of stay above 5 days).Data from 40 patients and 127 arterial and venous CO2 measurements for gap calculation taken 0-5 days postoperatively were available. The median (range) veno-arterial CO2 difference value was 9 (1-25 mmHg). The correlation between veno-arterial CO2 difference and cardiac index was not significant (r: -0.16, p = 0.08). However, there was a significant correlation between veno-arterial CO2 difference and vasoactive inotropic score (r: 0.21, p = 0.02), systolic arterial pressure (r: -0.43, p = 0.0001), dP/dtMAX (r: 0.26, p = 0.004), and arterio-venous O2 difference (r: 0.63, p = 0.0001). Systolic arterial pressure (OR 0.95, 95% CI 0.90-0.99), dP/dtMAX (OR 0.00, 95% CI 0.00-0.06), lactates (OR 1.87, 95% CI 1.21-3.31), and veno-arterial CO2 difference (OR 1.13, 95% CI 1.01-1.35) showed a significant univariate association with the complex clinical course. In conclusion, veno-arterial CO2 difference did not correlate with cardiac index estimated by MostCareTM in our cohort of post-cardiosurgical children, but it identified patients with the complex clinical course, especially when combined with other direct and indirect variables of perfusion.

Advanced Hemodynamic Monitoring in the Neonatal Intensive Care Unit

Clinical assessment of cardiac output by interpretation of indirect parameters has proven to be inaccurate, irrespective of the level of experience of the clinician. Objective cardiac output monitoring is feasible in newborn infants in intensive care. The most promising methods include transthoracic echocardiography, transcutaneous Doppler, electrical biosensing technologies, transpulmonary ultrasound dilution, and arterial pulse contour analysis. Simultaneous assessment of blood pressure and cardiac output enables the identification of the earliest stage of shock. Comprehensive hemodynamic monitoring is pivotal for an individualized pathophysiology-based hemodynamic management.

Assessment of cardiac function in infants with transposition of the great arteries after surgery: comparison of two methods

BACKGROUND

Assessment of cardiac function is crucial in pediatric patients undergoing cardiovascular surgery, monitoring cardiac output and changing hemodynamic conditions during surgery accordingly is important to improve post-surgical outcome. We aimed to measure cardiac index (CI) and maximal rate of the increase of left ventricular pressure dp/dt(max) with the pressure recording analytic method (PRAM, MostCare^®) and compared it with transthoracic echocardiographic cardiac index estimation in infants with transposition of the great arteries (TGA) undergoing surgical correction.

METHODS

We enrolled 74 infants with TGA consecutively into this study. CI and dp/dt(max) were measured with PRAM and echocardiography at 0, 4, 8, 12, 24 and 48 h postoperatively. Blood brain natriuretic peptide (BNP) and blood lactate (Lac) were measured at baseline and after operation.

RESULTS

The median age at surgery was 13 days (range 1-25 days) with an average weight of 3.24 kg (range 2.31-4.17 kg). CI estimated by PRAM was 1.11 ± 0.12 L/min/m² (range 0.69-1.36) and by Doppler echocardiography was 1.13 ± 0.13 L/min/m² (range 0.76-1.40). dp/dt(max) estimated by PRAM was 1.31 ± 0.03 mmHg/s (range 1.23-1.43) and by Doppler echocardiography was 1.31 ± 0.04 L/min/m² (range 1.25-1.47). CI (r = 0.817, P < 0.001) and dp/dt(max) (r = 0.794, P < 0.001) measured by two methods were highly correlated with a linear relation. Blood BNP and lactate increased to the highest level at 8-12 h post-operatively.

CONCLUSIONS

In the early post-operative period, PRAM provides reliable estimates of cardiac index and dp/dt(max) value compared with echocardiographic measurements. PRAM through mostcare^® is a reliable continuous monitoring method for peri-operative management in children with congenital heart disease.

Comparison between Pressure Recording Analytical Method and Fick Method to Measure Cardiac Output in Pediatric Cardiac Surgery

Background:

There is an increased interest in methods of objective cardiac output measurement in pediatric cardiac surgery. Several techniques are available, but have limitations, among the new technologies pressure recording analytical method with MostCare (MostCare-PRAM), a minimally invasive hemodynamic monitoring system, represents a novel arterial pulse contour method that does not require calibration. For this reason, we compared the MostCare-PRAM vs the Fick method for estimation of cardiac output.

Methods:

We studied prospectively 13 pediatric patients who underwent cardiac surgery and compared intraoperatively Cardiac Index (CI) measured with the MostCare-PRAM with the CI measured with the Fick method. We also measured Cardiac Cycle Efficiency (CCE) and maximal arterial pressure/time ratio (dp/dt max) and compared with Fick method.

Results:

The data showed good agreement between CI Fick and CI MostCare-PRAM (r = 0.93 and R2= 0.86; p < 0.0001) and also between CCE (r = 0.82 and R2 = 0.67; p < 0.001) and dp/dt (r = 0.84; R2 = 0.81; p < 0.001) with CI measured with Fick method.

Conclusion:

In pediatric patients submitted to cardiac surgery, the MostCare-PRAM seems to estimate CI with a good level of agreement with the Fick method measurements.

Prediction of Fluid Responsiveness Using Pulse Pressure Variation in Infants Undergoing Ventricular Septal Defect Repair with Median Sternotomy or Minimally Invasive Right Thoracotomy

Fluid management is challenging in infants after cardiopulmonary bypass. Pulse pressure variation (PPV) derived from pressure recording analytical method (PRAM) is based on lung-heart interaction during mechanical ventilation. A prospective observational study conducted in operating room tested PPV to predict fluid responsiveness in ventricular septal defect infants. Infants in open chest conditions with median sternotomy (n = 26) or minimally invasive right thoracotomy (n = 29) undergoing ventricular septal defect repair were enrolled. After cardiopulmonary bypass and modified ultrafiltration, all patients received fluid challenge. PPV was recorded using PRAM along with heart rate, diastolic blood pressure, stroke volume index (SVI), and cardiac index (CI) before and after volume replacement. Patients were considered as responders to fluid loading when CI increased ≥15%. In infants with median sternotomy, 12 were responders and 14 non-responders. PPV in responders was higher than that in non-responders (24.7 ± 6.4 vs. 16.6 ± 5.0%, P < 0.01). Area under the curve was 0.85 (95% confidence interval, 0.69-1, P = 0.001) and cutoff value 19% with a sensitivity of 92% and a specificity of 71%. In infants with minimally invasive right thoracotomy, 16 were responders and 13 non-responders. PPV in responders was higher than that in non-responders (25.0 ± 6.8 vs. 18.2 ± 5.3, P < 0.01). Area under the curve was 0.83 (95 confidence interval, 0.66-0.98, P = 0.001) and cutoff value 18% with a sensitivity of 94% and a specificity of 69%. PPV sensitively predicts fluid responsiveness in ventricular septal defect infants after surgical repair in open chest conditions both with median sternotomy and minimally invasive right thoracotomy.

Measuring cardiac output in children undergoing cardiac catheterization: comparison between the Fick method and PRAM (pressure recording analytical method)

BACKGROUND

Pressure recording analytical method (PRAM) is a novel, arterial pulse contour method for measuring cardiac output (CO). Validation studies of PRAM in children are few, and have shown contradictory results. The aim of the study was to compare the MostCare^® -PRAM vs the Fick method of cardiac output estimation (reference method).

METHODS

This is a single-center, prospective observational study in 52 pediatric patients who underwent diagnostic right and left heart catheterization. Cardiac index (CI) measurements with the MostCare^® -PRAM vs the Fick method were obtained under hemodynamically stable conditions.

RESULTS

Forty CI measurements were performed. The data showed good agreement between CI_Fick and CI_PRAM : r² = 0.90 (P < 0.001), mean bias -0.075, limits of agreement from -0.56 to 0.41. The percentage error was 17%. Comparable results were obtained for patients <20 kg (r² = 0.87, P < 0.001), mean bias -0.135, limits of agreement from -0.35 to 0.62, percentage of error 17%.

CONCLUSIONS

In pediatric patients undergoing diagnostic right and left heart catheterization, the MostCare^® -PRAM was shown to estimate CI with a good level of agreement with the Fick method measurements.

Latent AKI is… still AKI: the quantification of the burden of renal dysfunction

The association between pediatric cardiac surgery, acute kidney injury (AKI), and clinical outcomes has been studied several times in the recent literature. In this issue of Critical Care an interesting and original study analyzed the path from causal AKI entities to clinical AKI consequences through the application of structural equation modeling. The authors described the complex connections linking duration of cardiopulmonary bypass, cross clamp-time, and descriptors of low cardiac output syndrome to AKI modeled as a complex variable composed of post-operative serum creatinine increase of 50 % over baseline, urine output <0.5 ml/kg/h, and urine creatinine-normalized neutrophil gelatinase lipocalin within 12 h of surgery. Similarly, the causal relationships between AKI and hard outcomes in the analyzed population were verified and quantified. The authors, for the first time, produce a repeatable coefficient (0.741) that may become a useful quality benchmark and could be applied to test future interventions aiming to reduce the burden of AKI on children’s clinical course.

Fluid resuscitation therapy for paediatric sepsis

Sepsis and septic shock are the final common pathway for many decompensated paediatric infections. Fluid resuscitation therapy has been the cornerstone of haemodynamic resuscitation in these children. Good evidence for equivalence between 0.9% saline and 4% albumin, with the relative expense of the latter, has meant that 0.9% saline is currently the most commonly used resuscitation fluid world-wide. Evidence for harm from the chloride load in 0.9% saline has generated interest in balanced solutions as first line resuscitation fluids. Their safety has been well established in observational studies, and they may well be the most reasonable default fluid for resuscitation. Semi-synthetic colloids have been associated with renal dysfunction and death and should be avoided. There is evidence for harm from excessive administration of any resuscitation fluid. Resuscitation fluid volumes should be treated in the same way as the dose of any other intravenously administered medication, and the potential benefits versus harms for the individual patient weighed prior to administration.

Accuracy and precision of minimally-invasive cardiac output monitoring in children: a systematic review and meta-analysis

Several minimally-invasive technologies are available for cardiac output (CO) measurement in children, but the accuracy and precision of these devices have not yet been evaluated in a systematic review and meta-analysis. We conducted a comprehensive search of the medical literature in PubMed, Cochrane Library of Clinical Trials, Scopus, and Web of Science from its inception to June 2014 assessing the accuracy and precision of all minimally-invasive CO monitoring systems used in children when compared with CO monitoring reference methods. Pooled mean bias, standard deviation, and mean percentage error of included studies were calculated using a random-effects model. The inter-study heterogeneity was also assessed using an I(2) statistic. A total of 20 studies (624 patients) were included. The overall random-effects pooled bias, and mean percentage error were 0.13 ± 0.44 l min(-1) and 29.1 %, respectively. Significant inter-study heterogeneity was detected (P < 0.0001, I(2) = 98.3 %). In the sub-analysis regarding the device, electrical cardiometry showed the smallest bias (-0.03 l min(-1)) and lowest percentage error (23.6 %). Significant residual heterogeneity remained after conducting sensitivity and subgroup analyses based on the various study characteristics. By meta-regression analysis, we found no independent effects of study characteristics on weighted mean difference between reference and tested methods. Although the pooled bias was small, the mean pooled percentage error was in the gray zone of clinical applicability. In the sub-group analysis, electrical cardiometry was the device that provided the most accurate measurement. However, a high heterogeneity between studies was found, likely due to a wide range of study characteristics.

Perioperative cardiovascular monitoring of high-risk patients: a consensus of 12

A significant number of surgical patients are at risk of intra- or post-operative complications or both, which are associated with increased lengths of stay, costs, and mortality. Reducing these risks is important for the individual patient but also for health-care planners and managers. Insufficient tissue perfusion and cellular oxygenation due to hypovolemia, heart dysfunction or both is one of the leading causes of perioperative complications. Adequate perioperative management guided by effective and timely hemodynamic monitoring can help reduce the risk of complications and thus potentially improve outcomes. In this review, we describe the various available hemodynamic monitoring systems and how they can best be used to guide cardiovascular and fluid management in the perioperative period in high-risk surgical patients.

Furosemide versus ethacrynic acid in pediatric patients undergoing cardiac surgery: a randomized controlled trial

Introduction

Clinical effects of furosemide (F) and ethacrynic acid (EA) continuous infusion on urine output (UO), fluid balance, and renal, cardiac, respiratory, and metabolic function were compared in infants undergoing surgery for congenital heart diseases.

Methods

A prospective randomized double-blinded study was conducted. Patients received 0.2 mg/kg/h (up to 0.8 mg/kg/h) of either F or EA.

Results

In total, 38 patients were enrolled in the F group, and 36, in the EA group. No adverse reactions were recorded. UO at postoperative day (POD) 0 was significantly higher in the EA group, 6.9 (3.3) ml/kg/h, compared with the F group, 4.6 (2.3) ml/kg/h (P = 0.002) but tended to be similar in the two groups thereafter. Mean administered F dose was 0.33 (0.19) mg/kg/h compared with 0.22 (0.13) mg/kg/h of EA (P < 0.0001). Fluid balance was significantly more negative in the EA group at postoperative day 0: −43 (54) ml/kg/h versus −17 (32) ml/kg/h in the F group (P = 0.01). Serum creatinine, cystatin C and neutrophil gelatinase-associated lipocalin levels and incidence of acute kidney injury did not show significant differences between groups. Metabolic alkalosis occurred frequently (about 70% of cases) in both groups, but mean bicarbonate level was higher in the EA group: 27.8 (1.5) M in the F group versus 29.1 (2) mM in the EA group (P = 0.006). Mean cardiac index (CI) values were 2.6 (0.1) L/min/m² in the F group compared with 2.98 (0.09) L/min/m² in the EA group (P = 0.0081). Length of mechanical ventilation was shorter in the EA group, 5.5 (8.8) days compared with the F group, 6.7 (5.9) (P = 0.06). Length of Pediatric Cardiac Intensive Care Unit (PCICU) admission was shorter in the EA group: 14 (19) days compared with 16 (15) in the F group (P = 0.046).

Conclusions

In cardiac surgery infants, EA produced more UO compared with F on POD0. Generally, a smaller EA dose is required to achieve similar UO than F. EA and F were safe in terms of renal function, but EA caused a more-intense metabolic alkalosis. EA patients achieved better CI, and shorter mechanical ventilation and PCICU admission time.

Trial registration

Clinicaltrials.gov NCT01628731. Registered 24 June 2012.