Safety and efficacy of continuous renal replacement therapy for children less than 10 kg using standard adult machines.

Continuous Renal Replacement Therapy (CRRT) machines are used off-label in patients less than 20 kg. Infant and neonates-dedicated CRRT machines are making their way into current practice, but these machines are available only in select centres. This study assesses the safety and efficacy of CRRT using adult CRRT machines in children ≤ 10 kg and to determines the factors affecting the circuit life in these children. DESIGN: Retrospective cohort study of children ≤ 10 kg who received CRRT (January 2010-January 2018) at a PICU in a tertiary care centre in London, UK. Primary diagnosis, markers for illness severity, CRRT characteristics, length of PICU admission and survival to PICU discharge were collected. Descriptive analysis compared survivors and non-survivors. A subgroup analysis compared children ≤ 5 kg to children 5-10 kg. Fifty-one patients ≤ 10 kg received 10,328 h of CRRT, with median weight of 5 kg. 52.94% survived to hospital discharge. Median circuit life was 44 h (IQR 24-68). Bleeding episodes occurred with 6.7% of sessions and hypotension for 11.9%. Analysis of efficacy showed a reduction in fluid overload at 48 h (P = 0.0002) and serum creatinine at 24 and 48 h (P = 0.001). Blood priming was deemed to be safe as serum potassium decreased at 4 h (P = 0.005); there was no significant change in serum calcium. Survivors had a lower PIM2 score at PICU admission (P < 0.001) and had longer PICU length of stay (P < 0.001).    Conclusion: Pending neonatal and infant dedicated CRRT machines, CRRT can be safely and effectively applied to children weighing ≤ 10 kg using adult-sized CRRT machines. WHAT IS KNOWN: • Continuous Renal Replacement Therapy can be used for a variety of renal and non-renal indications to improve outcomes for children in the paediatric intensive care unit. These include, persistent oliguria, fluid overload, hyperkalaemia, metabolic acidosis, hyperlactatemia, hyperammonaemia, and hepatic encephalopathy. • Young children ≤ 10 kg are most often treated using standard adult machines, off-label. This potentially places them at risk of side effects due to high extracorporeal circuit volumes, relatively higher blood flows, and difficulty in achieving vascular access. WHAT IS NEW: • This study found that standard adult machines were effective in reducing fluid overload and creatinine in children ≤ 10 kg. This study also assessed safety of blood priming in this group and found no evidence of an acute fall in haemoglobin or calcium, and a fall in serum potassium by a median of 0.3 mmol/L. The frequency of bleeding episodes was 6.7%, and hypotension requiring vasopressors or fluid resuscitation occurred with 11.9% of treatment sessions. • These findings suggest that adult CRRT machines are sufficiently safe and efficacious for routine use in PICU for children ≤ 10 kg and suggest that further research is undertaken, regarding the routine rollout of dedicated machines.

Dialysis circuit clotting in critically ill patients with COVID-19 infection.

BACKGROUND: Coronavirus Disease 2019 (COVID-19) infection has been associated with a hypercoagulable state with increased reports of thrombotic events. Acute kidney injury requiring dialysis is common in critically ill patients and circuit clotting compromises efficacy of treatment. This study aims to analyze the circuit life and circuit clotting during continuous kidney replacement therapy (CKRT) and intermittent hemodialysis in patients with and without COVID-19. METHODS: This is a single-center, retrospective cohort study in critically ill patients undergoing CKRT or intermittent hemodialysis between 1 February 2020 to 22 May 2020. Patients in the intensive care unit (ICU) with COVID-19 infection and contemporary controls who tested negative were included. Co-primary outcomes were functional circuit life for patients on CKRT and all circuit clotting events for patients on CKRT and/or intermittent hemodialysis. RESULTS: Seventy CKRT circuits and 32 intermittent hemodialysis sessions for 12 COVID-19 cases and 22 CKRT circuits and 18 intermittent hemodialysis sessions for 15 controls were analyzed. CKRT circuit clotting was more common in the COVID-19 group compared to the control group (64% vs 36%, p = 0.02), despite higher anticoagulation use in the COVID-19 group (41% vs 14%, p = 0.02). Functional CKRT circuit life was similar in COVID-19 patients and controls (median 11 vs 12 h, p = 0.69). On Cox regression analysis, circuit clotting was similar with hazard ratio (HR) 1.90 [95% confidence interval (CI): 0.89-4.04]; however, clotting was increased in COVID-19 patients after adjustment for anticoagulation use (HR: 3.31 [95% CI 1.49-7.33]). In patients with COVID-19, CKRT circuits with anticoagulation had a longer circuit life compared to CKRT circuits without anticoagulation (median 22 versus 7 h respectively, p <  0.001). Circuit clotting was similar in both groups undergoing intermittent hemodialysis. CONCLUSION: Dialysis clotting amongst COVID-19 patients is increased despite more anticoagulation use and the hazard for clotting is greater especially after adjusting for anticoagulation use. Circuit life was suboptimal in COVID-19 patients on circuits without anticoagulation and therefore routine use of anticoagulation amongst COVID-19 patients should be considered whenever possible.

The effect of the AN69 ST100 versus oXiris® membrane on filter life during CRRT for non-anticoagulated liver failure patients.

BACKGROUNDS: In patients with liver failure, continuous renal replacement therapy (CRRT) without anticoagulation may be necessary. A new heparin coated membrane (oXiris®) may prolong circuit life in this setting. OBJECTIVES: In liver failure patients not receiving anticoagulation, to compare CRRT circuit life with the oXiris® versus the AN69 ST100 (usual care) membrane. METHODS: Randomized single cross-over trial. RESULTS: We studied 20 patients and 39 circuits. Twenty-five treatments used femoral and 14 internal jugular access catheters. Median circuit life was 21 h (IQR: 8.25-35.5) with the AN69 versus 16.0 h (14-25) with the oXiris® membrane (p = 0.36). Median first circuit duration was 14 (11.25-23) h for the AN69 ST100 versus 16 (8 -26) for the oXiris® membrane. There was also no difference between the AN69 ST100 or oXiris® membrane circuits using femoral access at 13 (8 -22.5) versus 15.5 (12.5-21.5) h (p = 0.57) or internal jugular access at 28 (13-47) versus 23 (21-29) h (p = 0.79), respectively. CONCLUSIONS: The oXiris® heparin-grafted membrane does not appear to prolong circuit life in liver failure patients receiving CRRT without anticoagulation.

Impact of connecting continuous renal replacement therapy to the extracorporeal membrane oxygenation circuit.

PURPOSE: Continuous veno-venous haemofiltration (CVVH) directly connected to extracorporeal membrane oxygenation (ECMO) may ensure better blood flow and allow prolonged circuit life. The objective of this study was to assess circuit life of CVVH connected to ECMO and to a dialysis catheter. MATERIALS AND METHODS: In this prospective observational study, patients receiving CVVH via ECMO were compared to time-matched patients receiving CVVH via a conventional dialysis catheter. CVVH circuit life and the safety and efficacy of the two CVVH procedures were analysed. Time to event was estimated using Kaplan-Meier analysis and compared using the log-rank test. RESULTS: Seventeen patients were included in each group, with 43 sessions in the ECMO group and 56 sessions in the DC group. Median CVVH circuit life was 48 [21-72] vs 20 [6-39] hours in the ECMO and DC groups, respectively (relative risk of termination of the session: 2.4, 95% CI [1.41-3.9], log rank P=0.0009). CVVH blood flow was higher in the ECMO group. Despite higher anticoagulant doses in the catheter group, the circuit clotting rate was lower in the ECMO group. Effluent volume was slightly higher in the ECMO group (39ml/kg/h [33-47] vs 34ml/kg/h [32-39]), but with no biological impact. CVVH via ECMO was well tolerated with no major drawbacks. CONCLUSIONS: In patients requiring ECMO, CVVH connected to ECMO instead of DC could be proposed as an alternative approach, allowing more stable blood flow and prolonged CVVH circuit life.

Circuit life versus bleeding risk: the impact of achieved activated partial thromboplastin time versus achieved filtration fraction.

Whilst prolonging hemofilter (circuit) life, heparin increases bleeding risk. The impact of achieved activated partial thromboplastin time (APTT) on circuit life and bleeding risk has not been assessed in a modern critically ill cohort. Lowering filtration fraction may be an alternative means of prolonging circuit life, but is often overlooked in critical care. An observational study of 309 consecutive circuits in a general intensive care unit was conducted using a wide target APTT range. Multilevel modeling was used to predict circuit life and bleeding according to achieved APTT and filtration fraction. Independent predictors of circuit failure (i.e. unplanned ending of treatment) included filtration fraction (P<0.001, HR 1.07 per 1% increase), peak APTT (P<0.001, HR 0.8 per 10 s increase or 0.3 APTR increase) and baseline PT (P=0.014, HR 0.91 for every 50% increase). The only significant predictor of bleeding was peak APTT (P=0.017, OR 1.05 per 10 s increase). Every 10 s APTT increase was associated with a 20% reduction in circuit failure, but a 5% increase in hemorrhage. A 3% reduction in filtration fraction was associated with the same improvement in circuit life as a 10 s increase in APTT. Increasing APTT prolongs circuit life but carries a substantial risk of bleeding even in modern practice. Filtration fraction has a large impact on circuit life in the critically ill: a 3% reduction in filtration fraction, e.g. by increasing blood flow or delivering some of the clearance via dialysis, would be expected to reduce circuit failure as much as a 10 s increase in APTT.