Effects of Initiation of Continuous Renal Replacement Therapy on Hemodynamics in a Pediatric Animal Model

The effect of citrate in cardiovascular system and clot circuit in critically ill patients requiring continuous renal replacement therapy

We aimed to evaluate the impact of citrate on hemodynamic responses and secondary outcomes, including the filter life span, metabolic complications, and levels of inflammatory cytokines, in critically ill patients who required CRRT compared with those who underwent the heparin-free method. This prospective, multicenter, open-label randomized trial compared regional citrate anticoagulation (RCA) with a heparin-free protocol in severe acute kidney injury (AKI) patients who received continuous venovenous hemodiafiltration (CVVHDF) in the postdilution mode. We measured hemodynamic changes using the FloTrac Sensor/EV1000™ Clinical Platform at certain time points after starting CRRT (0, 6, 12, 24, 48, and 72 h.). The levels of inflammatory cytokines (IL-1β, IL-6, IL-8, IL-10 and TNF-ɑ) were measured on days 1 and 3. Forty-one patients were recruited and randomized into the heparin (n = 20) and citrate groups (n = 21). The cardiac performances were not significantly different between the 2 groups at any time point. The inflammatory cytokines declined similarly in both treatment arms. The maximum filter survival time was insignificantly longer in the RCA group than in the heparin-free group (44.64 ± 26.56 h. vs p = 0.693 in citrate and heparin free group). No serious side effects were observed for either treatment arm, even in the group of liver dysfunction patients. RCA did not affect hemodynamic changes during CRRT. Inflammatory cytokines decreased similarly in both treatment arms.The filter life span was longer in the citrate group. RCA is a valid alternative to traditional anticoagulation and results in stable hemodynamic parameters.

Changes in hemodynamics, renal blood flow and urine output during continuous renal replacement therapies

Continuous renal replacement therapies (CRRT) affect hemodynamics and urine output. Some theories suggest a reduced renal blood flow as the cause of the decreased urine output, but the exact mechanisms remain unclear. A prospective experimental study was carried out in 32 piglets (2–3 months old) in order to compare the impact of CRRT on hemodynamics, renal perfusion, urine output and renal function in healthy animals and in those with non-oliguric acute kidney injury (AKI). CRRT was started according to our clinical protocol, with an initial blood flow of 20 ml/min, with 10 ml/min increases every minute until a goal flow of 5 ml/kg/min. Heart rate, blood pressure, central venous pressure, cardiac output, renal blood flow and urine output were registered at baseline and during the first 6 h of CRRT. Blood and urine samples were drawn at baseline and after 2 and 6 h of therapy. Blood pressure, cardiac index and urine output significantly decreased after starting CRRT in all piglets. Renal blood flow, however, steadily increased throughout the study. Cisplatin piglets had lower cardiac index, higher vascular resistance, lower renal blood flow and lower urine output than control piglets. Plasma levels of ADH and urine levels of aquaporin-2 were lower, whereas kidney injury biomarkers were higher in the cisplatin group of piglets. According to our findings, a reduced renal blood flow doesn’t seem to be the cause of the decrease in urine output after starting CRRT.

Continuous kidney replacement therapy in critically ill neonates and infants: a retrospective analysis of clinical results with a dedicated device

BACKGROUND

Providing extracorporeal renal support to neonates and infants involves a number of technical and clinical issues, possibly discouraging early utilization. This report aims to describe a multicenter experience of continuous kidney replacement therapy (CKRT) delivery to small infants using a device specifically designed for this age group.

METHODS

A retrospective cohort analysis of all patients treated with the Carpediem™ machine (Bellco-Medtronic, Mirandola, Italy) in 6 centers between June 2013 and December 2016.

RESULTS

Twenty-six neonates and small infants received 165 CKRT sessions in convective modality. Median age at neonatal intensive care unit admission 1 day (IQR 1-11), median body weight 2.9 kg (IQR 2.2-3.6). Median circuit duration 14 h (IQR 10-22), with delivered/prescribed time ratio of 84%. CKRT was conducted using 4 Fr (27%), 5 Fr (35%), 6.5 Fr (11%), and 7 Fr (3%) vascular access, and with umbilical and peripheral accesses (11% each) allowing overall median blood flow of 4.5 ml/kg/min (IQR 3.4-6) and median effluent flow rate 35 ml/kg/h (IQR 28-42). Circuits were primed with normal saline in 58% of treatments, colloids in 31%, and packed red blood cells in 11%. No serious adverse events directly related to machine application were reported by any center. Twenty-five (96%) patients survived their CKRT course and 13 patients (50%) survived to ICU discharge.

CONCLUSIONS

CKRT in neonates was easy to initiate and conduct when performed with small central vascular accesses coupled with this device. A dedicated technology for infant CKRT delivery enables patients to be safely treated avoiding technical complications. Graphical abstract.

Hemodynamic Effects of Connection to Continuous Renal Replacement Therapy in a Pediatric Animal Model

To assess the hemodynamic effects of connection to continuous renal replacement therapy (CRRT) in a pediatric experimental animal model. Prospective experimental study was performed using piglets between 2 and 3 months of age and 9-11 kg. CRRT with a Prismaflex^R monitor and HF20 filter (surface of 0.2 m² ) was started after monitoring and anesthetic induction with an initial blood flow at 20 mL/min with 10 mL/min increases every minute until the goal flow of 5 mL/kg/min was achieved. Heart rate, blood pressure, central venous pressure, cardiac index, and renal blood flow were registered at baseline, 5, 15, 30, 60, 120, 180, 240, and 360 min. IBM SPSS Statistics 20.0 package was used for analysis. A P value of <0.05 was considered statistically significant. Thirty-four piglets were studied. Blood pressure, cardiac output, and systemic vascular resistance significantly decreased 5-min after CRRT connection (mean arterial pressure from 85.5 to 70.8 mm Hg, P < 0.001, cardiac index from 3.6 to 3.3 L/min/m² P = 0.024, and systemic vascular resistance index from 1759 to 1607 dyn.s/cm⁵ P = 0.012). No significant changes were found in renal blood flow or central venous pressure. All parameters gradually increased at 15 and 30 min after connection but complete recovery was never achieved. Connection to CRRT produces a significant decrease in arterial pressure, cardiac index, and peripheral vascular resistances in hemodynamically stable piglets.

Effect of continuous blood purification on concentrations of plasma vasoactive substances and cardiac function in endotoxic shock

OBJECTIVE

To evaluate the effect of continuous blood purification on cardiac function and plasma vasoactive substances in endotoxic shock in piglets.

DESIGN

This was a randomized controlled trial in an animal laboratory in a tertiary care pediatric center.

MATERIALS AND METHODS

Twenty-three healthy Shanghai white piglets weighing 8-14 kg were randomly assigned to one of the four groups: control group (n = 5), continuous blood purification without lipopolysaccharide infusion group (continuous blood purification, n = 6), lipopolysaccharide-induced endotoxin shock without continuous blood purification group (lipopolysaccharide, n = 6), and lipopolysaccharide-induced endotoxin shock with continuous blood purification group (continuous blood purification/lipopolysaccharide, n = 6).

INTERVENTIONS

The lipopolysaccharide and continuous blood purification/lipopolysaccharide groups were injected intravenously with Escherichia coli endotoxin to induce septic shock. The continuous blood purification and continuous blood purification/lipopolysaccharide groups received continuous venovenous hemodiafiltration right after model establishment. At baseline state (T0), following the injection of lipopolysaccharide (T), 1 hr later (T1), 3 hrs later (T3), and 5 hrs later (T5) after model establishment, clinical systemic inflammatory response syndrome parameters, hemodynamic indexes, and plasma concentration of vasoactive substances were obtained. Plasma concentration of dopamine was measured by enzyme-linked immunosorbent assay (DSL Company) and endothelin-1 by enzyme-linked immunosorbent assay (R&D Company). Nitric oxide synthase activity was measured by chromatometry (Nanjing Jiancheng Bioengineering Institute, China).

MEASUREMENTS AND MAIN RESULTS

In continuous blood purification/lipopolysaccharide group, after treatment with CPB, heart rate decreased significantly (p < .05) and pulse contour cardiac index, systematic vascular resistance index, and stroke volume index increased significantly (p < .05) when compared with lipopolysaccharide and continuous blood purification groups. After treatment with continuous blood purification, dopamine and endothelin-1 level increased and nitric oxide synthase activities decreased in continuous blood purification/lipopolysaccharide group when compared with the lipopolysaccharide group. In the continuous blood purification/lipopolysaccharide group, improvement in hemodynamic indexes was strongly correlated with increases in plasma dopamine and endothelin-1 level and decreases in nitric oxide synthase activity (r > .9, p < .05).

CONCLUSIONS

The adverse cardiovascular effects of lipopolysaccharide-induced endotoxin shock can be improved by continuous blood purification. Improvement is correlated with increases in the concentration of plasma vasoactive substances (endothelin and dopamine) and decreases in nitric oxide synthase activity.