Abstract 10475: Heat Loss Augmented by Extracorporeal Circulation is Associated with Overcooling in Cardiac Arrest Survivors Who Underwent Targeted Temperature Management

Introduction: Extracorporeal circuit-based salvage therapy can affect targeted temperature management (TTM) in comatose out-of-hospital cardiac arrest (OHCA) survivors. We investigated the association of patients with extracorporeal device with TTM and neurological outcome. Methods: We performed a retrospective analysis using prospectively collected data from adult comatose OHCA survivors who underwent TTM between October 2015 and December 2020. We defined patients with ECMO and/or CRRT as the extracorporeal group. We calculated the cooling rate during the induction period; the minimum, maximum, and mean time-weighted core temperatures (TWCT), and the standard deviation (SD) of the core temperature and water temperature during the maintenance period based on the temperature measured every minute. We defined the sum of TWCT more and less than 33°C as positive and negative TWCT, respectively. The primary outcome was a poor neurological outcome, defined as cerebral performance category 3-5. We used propensity score (PS) matching to adjust the characteristics of patients who required an extracorporeal circuit device. Results: Of the 223 included patients, 140 (62.8%) patients had poor neurological outcome and 40 (17.9%) patients were categorized into the extracorporeal group. The extracorporeal group had a rapid cooling rate (2.08°C/h [1.13-3.73] vs. 1.24°C/h [0.77-1.79]; p < 0.001). The extracorporeal group had lower mean core temperature; higher core temperature SD; lower positive TWCT; higher negative TWCT; and higher maximum, minimum, and mean water temperature than the no-extracorporeal group. In PS matched cohort, the extracorporeal group had a lower minimum core temperature, lower mean core temperature, higher core temperature SD, higher negative TWCT, higher maximum water temperature, and higher mean water temperature. The neurological outcomes were not different between the two groups, in either the whole or PS-matched cohort. Conclusions: The extracorporeal group achieved the target temperature earlier. The core temperature distribution during the maintenance period was further skewed below 33°C in the extracorporeal group. The extracorporeal group had similar neurological outcomes to the no-extracorporeal group.

Effect of Roller Pump Pulse in the Arterial Needle Area during Hemodialysis

Vascular access is a lifeline for hemodialysis patients. Its lifetime is affected by many hemodynamic factors such as pressure, flow regime and wall shear stress. During hemodialysis, changes in hemodynamic parameters occur due to the flow from needles inserted into the vascular system. Primarily, there is a change in shear stress that affects the vascular wall. Pathological effects of high or low WSS are known. The effect of jet from a venous needle on hemodynamics parameters was studied, but the influence of the arterial needle on hemodynamics parameters is not sufficiently studied. To understand its possible effects, we performed in vivo and in vitro studies. Methods. In vivo experiment: The existence of flow reversal around the suction needle was visualized in a group of 12 randomly selected patients using ultrasound velocity profiling (Doppler ultrasonography) during hemodialysis. In vitro experiment: The flow field was measured using the stereo particle image velocimetry method (stereo PIV). Two regimes were studied. In the first regime, the fluid in the extracorporeal circuit was pumped by a peristaltic pump. In the second regime, the continuous pump was used in the extracorporeal circuit. The conditions were set to resemble those in vascular access during a hemodialysis session. Flow volume was set to 600 mL/min for vascular access and 200 mL/min for the extracorporeal circuit. Results. The main finding of this study was that the wall in the region of the arterial needle was stressed by backflow through the arterial needle. Since this was a variable, low-shear stress loading, it was one of the risk factors for the development of stenosis. Cyclic flow reversal was apparent in all of the included hemodialysis patients. The stereo PIV in vitro experiment revealed the oscillating character of wall shear stress (WSS) inside the model. High shear stress was documented upstream of the injection point of the arterial needle. An area of very low WSS was detected right behind the injection point during a pulse of the peristaltic pump. The minimal and maximal values of the WSS during a pulse of the peristaltic pump in the observed area were −0.7 Pa and 6 Pa, respectively. The distribution of wall shear stress with the continual pump used in the extracorporeal circuit was similar to the distribution during a pulse of the peristaltic one. However, the WSS values were continual; the WSS did not oscillate. WSS ranged between 4.8 Pa and 1.0 Pa.

Complex protocol of cardiopulmonary bypass

Background. Innovative advances in cardiac surgery to reduce the negative impact of cardiopulmonary bypass (CPB) require a comprehensive solution. The ultimate questions of present interest remain the prevention of hypoxia, the composition of the priming volume of the oxygenator, the state of erythrocytes and their energy potential, the level of hemolysis, the pathogenetic approach to the correction of electrolytes during perfusion, as well as the biocompatibility of the extracorporeal circuit. The study aimed to create the protocol for cardiopulmonary bypass, which includes the possibility of reducing the negative effects of synthetic polymers of the extracorporeal circuit; reducing the hydrodynamic load on the tissue; carrying out a more physiological correction of the acid-base state; improving the energy potential of cells; correction of electrolyte balance during cardiopulmonary bypass ta­king into account the stages of the surgical operation. Materials and methods. The study included 225 patients who underwent cardiac surgery using cardiopulmonary bypass. The patients were divided into three groups. The first group consisted of 75 people, whose extracorporeal contour was treated with the adaptive composition by a special technique. After centrifuging the patient’s blood, serum was obtained, which was diluted in a solution of 0.9% NaCl and treated with the oxygenator circuit. The second group included patients (n = 75) in whom fructose-1,6-diphosphate (FPD) was used in the perfusion regimen. The drug was administered intravenously at a dose of 10 g at a rate of 10 ml/min in two stages: 5 g of FPD were injected immediately before the start of perfusion and 5 g before the patient was warmed up. The third group was the control group. Perfusion was performed using a membrane oxygenator in a non-pulsating blood flow mode with a prime of 1.3–1.6 L to achieve moderate hemodilution (Ht — 25 ± 2 g/L). A hyperosmolar priming volume with a total osmolarity of up to 510.6 mmol/L was used. The basic solutions were volutens, reosorbilact, mannitol 15%, Soda-buffer 4.2%. Hemogram (Hb, Ht, MCV, MCH, MCHC, RDWa, RDW%, hemolysis), oxygen transport: saturation of arterial (SaO2%) and venous blood (SvO2%), partial pressure of oxygen in arterial (PaO2) and venous blood (PvO2), oxygen delivery index (IDO2), oxygen consumption index (IVO2), oxygen extraction (O2ER), and oxygen extraction index (O2EI) were studied. The research of morphological changes in erythrocytes was carried out. Results. Our study aimed to develop and implement into practice an optimized cardiopulmonary bypass protocol based on the results obtained. The previous studies have shown that treatment of the oxy-genator circuit with the adaptive composition creates a protective layer of autoalbumin on the inner surface of the extracorporeal circuit, and the use of a drug with the active fructose-1,6-diphosphate ingredient during perfusion allows correcting hypophosphatemia, reducing the energy deficiency of the cells. In these two groups, in comparison with the control one, after CPB, there was a lower level of hemolysis, a lower number of echinocytes, and spherocytes. The three groups used the hyperosmolar priming ­volume. Before perfusion, there were the following indices: IDO2 — 332.00 ± ± 84.84 ml/(min • m2), IVO2 — 76.07 ± 28.34 ml/(min • m2), O2ЕR — 22.91 ± 6.33 %, O2EI — 22.47 ± 6.32 %, BE = –0.78 ± 2.13 mmol/L. At 10 min after CPB, there were the following indices: IDO2 — 579.7 ± 112.3 ml/(min • m2), IVO2 — 30.91 ± 13.31 ml / (min • m2), O2ER — 5.35 ± 2.07 %, O2EI — 5.26 ± ± 2.08 %, BE = 0.82 ± 2.03 mmol/L. IDO2 increased due to the oxygenator gas exchange, and the decrease in IVO2, O2ЕR, O2EI can be explained by the patient’s cooling. At the warming stage, there were the indices: IDO2 — 598.8 ± 114.9 ml/(min • m2), IVO2 — 108.10 ± 33.11 ml/(min • m2), O2ER — 18.04 ± 4.14 %, O2EI — 17.95 ± 4.15 %, BE = –0.11 ± 8.88 mmol/L. IDO2 — 305.7 ± 60.9 ml / min • m2), IVO2 — 77.15 ± 24.29 ml/(min • m2), O2ЕR — 25.36 ± 6.5 %, O2EI — 25.34 ± 6.5 %, BE = –0.36 ± 2.20 mmol/L. After CPB, the rate of diuresis was 11.88 ± 5.31 ml/kg/h, the relative hydrobalance after CPB was 9.67 ± 8.12 ml/kg. Our proposed protocol for cardiopulmonary bypass includes the basic points: 1) treatment of the oxygenator contour with the adaptive composition; 2) in patients with an initially low level of phosphorus, administration of the drug of fructose-1,6-diphosphate by the scheme; 3) the use of a hyperosmolar priming volume of the oxygenator; 4) correction of electrolytes taking into account the stages of cardiac surgery. Conclusions. The proposed procedure for the treatment of the extracorporeal oxygenator circuit is simple and affordable, improves the biocompatibility of the oxygenator. The use of a hyperosmolar priming volume avoids the volume load and provides an adequate gas transport function of the blood. The application of FPD makes it possible to reduce hemolysis and protect erythrocytes, correct electrolytes by taking into account the stages of operations and the peculiarities of CPB.

Effect of Dynamic Circuit Pressures Monitoring on the Lifespan of Extracorporeal Circuit and the Efficiency of Solute Removal During Continuous Renal Replacement Therapy

Objective: To observe the effects of dynamic pressure monitoring on the lifespan of the extracorporeal circuit and the efficiency of solute removal during continuous renal replacement therapy (CRRT).Materials and Methods: A prospective observational study was performed at the West China Hospital of Sichuan University in the ICU. Analyses of the downloaded pressure data recorded by CRRT machines and the solute removal efficiencies, calculated by 2*Ce/(Cpre+Cpost), where Ce, Cpre, and Cpost are the concentrations of the effluent, pre-filter blood, and post-filter blood, respectively, were performed. Samples were collected at 0, 2, 6, 12, and 24 h when continuous veno-venous hemodiafiltration (CVVHDF) was used after the initiation of CRRT. Measurements in concentrations of creatinine, blood urea nitrogen, and β2-microglobulin in the plasma and effluent were recorded.Results: Extracorporeal circuits characterized by moderate-to-severe (M–S) access outflow dysfunction (AOD) events, defined as access outflow pressure less than or equal to −200 mmHg for more than 5 min, had shorter median lifespans with no anticoagulation (32.3 vs. 10.90 h, P = 0.001) compared with the no M–S AOD events group. The significant outcome also existed in regional citrate anticoagulation (RCA) (72 vs. 42.47 h, P = 0.02). Moreover, Cox regression analysis revealed that the lack of M–S AOD events, RCA, or CVVHDF independently prolonged the circuit lifespan. All tested solutes removal efficiencies started to decline at 12 h. Furthermore, efficiencies of all solutes removal dropped obviously at 24 h when TMP ≥ 150 mmHg.Conclusion: RCA and CVVHDF predicted a longer circuit lifespan. M–S AOD events were associated with a shorter circuit lifespan when RCA or no anticoagulant was used. Replacement of extracorporeal circuit could be considered when running time of filter lasted up to 24 h with TMP ≥ 150 mmHg.

Dextrose solution for priming and rinsing the extracorporeal circuit in hemodialysis patients: A prospective pilot study

Introduction: Excess sodium intake and consequent volume overload are major clinical problems in hemodialysis (HD) contributing to adverse outcomes. Saline used for priming and rinsing of the extracorporeal circuit is a potentially underappreciated source of intradialytic sodium gain. We aimed to examine the feasibility and clinical effects of replacing saline as the priming and rinsing fluid by a 5% dextrose solution. Materials and methods: We enrolled non-diabetic and anuric stable HD patients. First, the extracorporeal circuit was primed and rinsed with approximately 200–250 mL of isotonic saline during 4 weeks (Phase 1), subsequently a similar volume of a 5% dextrose solution replaced the saline for another 4 weeks (Phase 2), followed by another 4 weeks of saline (Phase 3). We collected data on interdialytic weight gain (IDWG), pre- and post-dialysis blood pressure, intradialytic symptoms, and thirst. Results: Seventeen chronic HD patients (11 males, age 54.1 ± 18.7 years) completed the study. The average priming and rinsing volumes were 236.7 ± 77.5 and 245.0 ± 91.8 mL respectively. The mean IDWG did not significantly change (2.52 ± 0.88 kg in Phase 1; 2.28 ± 0.70 kg in Phase 2; and 2.51 ± 1.2 kg in Phase 3). No differences in blood pressures, intradialytic symptoms or thirst were observed. Conclusions: Replacing saline by 5% dextrose for priming and rinsing is feasible in stable HD patients and may reduce intradialytic sodium loading. A non-significant trend toward a lower IDWG was observed when 5% dextrose was used. Prospective studies with a larger sample size and longer follow-up are needed to gain further insight into the possible effects of using alternate priming and rinsing solutions lowering intradialytic sodium loading. Trial registration: Identifier NCT01168947 (ClinicalTrials.gov).

MO665THE BRAND-NEW NEEDLE CAP ELIMINATES ALL VISIBLE AIR BUBBLES DURING THE AUTOMATIC PRIMING PROCESS OF HEMODIALYSIS MACHINES

Background and Aims The air contamination from the dialysis circuit into the patient's body is an unsolved serious problem. Recently, Automatic priming function of dialysis machines is widely used. There are rarely any air bubbles left in the extracorporeal circuit after automatic priming of the dialysis machines. To use this method, the arterial and venous sides of the extracorporeal circuit are connected to create a closed circuit so that dialysate can circulate and overflowed through a line from this closed circuit. However, air bubbles may enter when disconnecting the closed extracorporeal circuit and attaching the needles. We tried to solve this problem by simply connecting the arterial and venous needles to the extracorporeal closed circuit before the process of automatic priming process. To prime the whole extracorporeal circuit with needles, we had made a brand-new suitable cap of the needle, which is tightly connected with a needle and has an open end. (Fig) This special cap allows the needle to be incorporated into the closed circuit prior to the automatic priming process, allowing the dialysis machine to completely remove the air during priming process. The purpose of this study is to present the details of this new method and compare its effectiveness in preventing air bubble contamination between the traditional method and this new method. Method A prospective, non-randomized, comparative study was conducted to verify whether air remained grossly visible after the needle was connected to the extracorporeal circuit. The traditional method: DCS-100NX (Nikkiso Co Ltd, Tokyo Japan) was used for extracorporeal circuit priming. After the automatic priming was finished. Nurses disconnect the arterial and venous side of the extracorporeal circuit and connect both ends to the needles by hands. The nurse operates the dialysis machine to blow the small amount of dialysate out of the needle and tried to remove the air. It takes nearly 2minutes in each case. We examined the extracorporeal circuits consecutively. New cap-based method: The needles were connected to the closed circuit with the new cap and auto-primed by the dialysis machine N100. Automatic priming, including the needle were performed consecutively. In each method, we thoroughly checked for any remaining macro bubbles with the naked eye. Since bubbles in the extracorporeal circuit on the arterial side are likely to be supplemented by the air trap chamber, only bubbles on the venous side were compared. Results The study was conducted in October 15th to 24th 2020 at the Yokohama Minami Clinic. The traditional method: We checked 50 extracorporeal circuits consecutively. There were bubbles in the venous side of the extracorporeal circuits 29 times out of 50 times. New cap-based method: 10 consecutive automatic priming, including the needle was performed. DCS-100NX was used as the dialysis machine. There were no bubbles visible to the naked eye in the arterial and venous side of the circuit. Statistical Results There was a statistically significant difference of the bubble count between the traditional method and new cap-based method. (p=0.0001, Pearson's chi-square test) Conclusion All visible bubbles were removed automatically by simply connecting the needles using this brand-new cap before a process of automatic priming. This easy-to-use and highly effective cap could be considered an essential device for hemodialysis treatment like seat belts in automobiles.

MO675HEMOADSORPTION WITH CYTOSORB® CARTRIDGE IN PEDIATRIC INTENSIVE CARE UNIT – A SERIES OF FOUR CASES

Background and Aims Hemoadsorption with Cytosorb® cartridge is one of extracorporeal blood purification therapies increasingly used in adult intensive care units in conditions with elevated inflammatory mediators. Many positive experiences of hemodynamic improvement of patients treated with hemoadsorption have resulted in attempts of its application also in critically ill pediatric patients. Here we present a case series of four children treated with hemoadsorption in pediatric intensive care unit (PICU) of University Medical Centre Ljubljana from September 2018 to January 2019. Method All patients were mechanically ventilated and required vasopressor and inotropic support. Hemoadsorption was used as a rescue therapy after all standard treatments for their underlying condition had been insufficient. CytoSorb® cartridge was coupled with continuous veno-venous hemodialysis (CVVHD, Prismaflex system, Gambro) in pre-filter (ST60 set, Gambro) position. In children &lt;10 kg body weight (2 infants), the extracorporeal circuit was prefilled with a 1:1 mixture of packed red blood cells and saline, with heparin added. Automated regional citrate anticoagulation was used, blood flow was 30-100 ml/min and dialysate flow 500 ml/h. Results The youngest child was 10 days old 1.9 kg premature female with acute liver failure due to gestational alloimmune liver disease. CVVHD was started for hyperammonemia and concomitant CytoSorb® for severe hyperbilirubinemia (335 umol/l). Procedure was discontinued after 6 hours due to uncontrollable sepsis and hemodynamic collapse. We managed to normalize ammonia values and reduce bilirubin concentration (116 umol/l). Further treatment was withdrawn as a result of irreversible multiorgan failure. One month old 2.5 kg female patient was treated in PICU due to necrotizing enterocolitis and refractory septic shock with multiorgan failure. Oliguric acute kidney injury (AKI) required CVVHD and later on Cytosorb ® was added as an attempt to limit severe hyperinflammatory condition. During 19 hours of treatment the need for vasopressor support was increasing and metabolic acidosis was deepening. The patient required a short resuscitation a couple of hours into the procedure due to bradycardia which resulted in catheter and CVVHD circuit thrombosis. Dialysis was discontinued as urgent surgery was necessary. The patient later died of uncontrolled septic shock. Three years old 17 kg male was admitted with meningococcal septic shock, requiring initiation of veno-arterial ECMO. Cytosorb® with CVVHD was started and attached to the ECMO circuit. A significant decline of interleukine-6 (IL-6) was achieved without any procedure-related side effect and treatment was discontinued after 68 hours as patient's clinical status notably improved. The patient survived. Five years old 20 kg female patient, actively treated for acute lymphoblastic leukemia, was admitted with E. coli sepsis. Septic shock was unresponsive to conventional treatment therefore she was started on Cytosorb® with CVVHD as oliguric AKI also developed. Two consecutive procedures were preformed, the first for 31 and the second for 37 hours. Level of IL-6 decreased (from &gt; 5000 ng/L to 1000 ng/L) and lactate level normalized. We achieved reduction in vasopressors and oxygen need during both procedures and patient's overall status greatly improved. Conclusion Although significantly increasing the volume of extracorporeal circuit, the use of Cytosorb® cartridge within CVVHD circuit is technically feasible even in critically ill children with low body weight, if principles of pediatric renal replacement therapy are considered. More efficacy and safety data on Cytosorb® utilization are necessary before inclusion in routine clinical practice. Treatment outcome is highly dependent on primary disease and severity of patient condition.