Left Anterior Descending Coronary Artery Blood Flow and Left Ventricular Unloading During Extracorporeal Membrane Oxygenation Support in a Swine Model of Acute Cardiogenic Shock

The impact of extracorporeal membrane oxygenation (ECMO) support on coronary blood flow and left ventricular unloading is still debated. This study aimed to further characterize the influence of ECMO on coronary artery blood flow and its ability to unload the left ventricle in a short‐term model of acute cardiogenic shock. Seven anesthetized pigs were intubated and then underwent median sternotomy and cannulation for venoarterial (VA) ECMO. Flow in the left anterior descending (LAD) artery, left atrial pressure (LAP), left ventricular end‐diastolic pressure (LVEDP), and mean arterial pressure (MAP) were measured before and after esmolol‐induced cardiac dysfunction and after initiating VA‐ECMO support. Induction of acute cardiogenic shock was associated with short‐term increases in LAP from 8 ± 4 mm Hg to 18 ± 14 mm Hg (P = 0.9) and LVEDP from 5 ± 2 mm Hg to 13 ± 17 mm Hg (P = 0.9), and a decrease in MAP from 63 ± 16 mm Hg to 50 ± 24 mm Hg (P = 0.3). With VA‐ECMO support, blood flow in the LAD increased from 28 ± 25 mL/min during acute unsupported cardiogenic shock to 67 ± 50 mL/min (P = 0.003), and LAP and LVEDP decreased to 8 + 5 mm Hg (P = 0.7) and 5 ± 3 mm Hg (P = 0.5), respectively. In this swine model of acute cardiogenic shock, VA‐ECMO improved coronary blood flow and provided some degree of left ventricular unloading for the short duration of the study.     

New Generation Extracorporeal Membrane Oxygenation With MedTech Mag‐Lev,a Single‐Use,Magnetically Levitated,Centrifugal Blood Pump: Preclinical Evaluation in Calves

We have evaluated the feasibility of a newly developed single‐use, magnetically levitated centrifugal blood pump, MedTech Mag‐Lev, in a 3‐week extracorporeal membrane oxygenation (ECMO) study in calves against a Medtronic Bio‐Pump BPX‐80. A heparin‐ and silicone‐coated polypropylene membrane oxygenator MERA NHP Excelung NSH‐R was employed as an oxygenator. Six healthy male Holstein calves with body weights of about 100 kg were divided into two groups, four in the MedTech group and two in the Bio‐Pump group. Under general anesthesia, the blood pump and oxygenator were inserted extracorporeally between the main pulmonary artery and the descending aorta via a fifth left thoracotomy. Postoperatively, both the pump and oxygen flow rates were controlled at 3 L/min. Heparin was continuously infused to maintain the activated clotting time at 200–240 s. All the MedTech ECMO calves completed the study duration. However, the Bio‐Pump ECMO calves were terminated on postoperative days 7 and 10 because of severe hemolysis and thrombus formation. At the start of the MedTech ECMO, the pressure drop across the oxygenator was about 25 mm Hg with the pump operated at 2800 rpm and delivering 3 L/min flow. The PO₂ of the oxygenator outlet was higher than 400 mm Hg with the PCO₂ below 45 mm Hg. Hemolysis and thrombus were not seen in the MedTech ECMO circuits (plasma‐free hemoglobin [PFH] < 5 mg/dL), while severe hemolysis (PFH > 20 mg/dL) and large thrombus were observed in the Bio‐Pump ECMO circuits. Plasma leakage from the oxygenator did not occur in any ECMO circuits. Three‐week cardiopulmonary support was performed successfully with the MedTech ECMO without circuit exchanges. The MedTech Mag‐Lev could help extend the durability of ECMO circuits by the improved biocompatible performances.     

Use of extracorporeal membrane oxygenation in combination with high‐frequency oscillatory ventilation in post‐traumatic ARDS

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are life‐threatening complications in trauma patients. Despite the implantation of a veno‐venous extracorporeal membrane oxygenation (vv ECMO), sufficient oxygenation (arterial SaO₂ > 90%) is not always achieved. The additive use of high‐frequency oscillation ventilation (HFOV) and ECMO in the critical phase after trauma could prevent the occurrence of life‐threatening hypoxaemia and multi‐organ failure. We report on a 26‐year‐old female (Injury Severity Score 29) who had multiple injuries as follows: an unstable pelvic fracture, a blunt abdominal trauma, a blunt trauma of the left thigh, and a thoracic injury. Three days after admission, the patient developed fulminant ARDS (Murray lung injury score of 11 and Horovitz‐ Index <80 mmHg), and vv ECMO therapy was initiated. The Horovitz‐ Index was <80 mm Hg, and the lung compliance was minimal. With HFOV, almost complete recruitment of the lung was achieved, and the fraction of inspired oxygen (FiO₂) was significantly reduced. The pelvic fracture was treated non‐operatively. The HFOV was terminated after 3 days, and the ECMO was stopped after 19 days.     

A Novel Oxygenated Machine Perfusion System for Preservation of the Liver

Machine perfusion (MP) is a potential method to increase the donor pool for organ transplantation. However, MP systems for liver grafts remain difficult to use because of organ‐specific demands. Our aim was to test a novel, portable MP system for hypothermic preservation of the liver. A portable, pressure‐regulated, oxygenated MP system designed for kidney preservation was adapted to perfuse liver grafts via the portal vein (PV). Three porcine livers underwent 20 h of hypothermic perfusion using Belzer MP solution. The MP system was assessed for perfusate flow, temperature, venous pressure, and pO₂/pCO₂ during the preservation period. Biochemical and histological parameters were analyzed to determine postpreservation organ damage. Perfusate flow through the PV increased over time from 157 ± 25 mL/min at start to 177 ± 25 mL/min after 20 h. PV pressure remained stable at 13 ± 1 mm Hg. Perfusate temperature increased from 9.7 ± 0.6°C at the start to 11.0 ± 0.0°C after 20 h. Aspartate aminotransferase and lactate dehydrogenase increased from 281 ± 158 and 308 ± 171 U/L after 1 h to 524 ± 163 and 537 ± 168 U/L after 20 h, respectively. Blood gas analysis showed a stable pO₂ of 338 ± 20 mm Hg before perfusion of the liver and 125 ± 14 mm Hg after 1 h perfusion. The pCO₂ increased from 15 ± 5 mm Hg after 1 h to 53 ± 4 mm Hg after 20 h. No histological changes were found after 20 h of MP. This study demonstrated the feasibility of a portable MP system for preservation of the liver and showed that continuous perfusion via the PV can be maintained with an oxygen‐driven pump system without notable preservation damage of the organ.     

Modification of a Pivot Bearing System on a Compact Centrifugal Pump

Abstract: The pivot bearing centrifugal blood pump was developed as a long-term centrifugal ventricular assist device (VAD) as well as a cardiopulmonary bypass pump. This pivot bearing supported centrifugal pump with an eccentric port (C1E) incorporates a seal-less design with a blood stagnation-free structure. This pump can provide flows of 12 L/min against 650 mm Hg total pressure head at 3,600 rpm, and in a CPB condition 5 L/min against 350 mm Hg total pressure head at 2,600 rpm. Very recently, the pivot bearing system was modified to obtain a stable and smooth spinning movement. The material of the female pivot was changed from ceramic to polyethylene. Three kinds of bearings were tested simultaneously with bovine blood in two types of in vitro circuits to determine the blood damage from the bearings. Pressure differences across the pump (total head pressure, A/¹) of 140 mm Hg (n = 12) and 330 mm Hg (n = 12) were examined. The normalized index of hemolysis (NIH) was slightly higher in a ball bearing (BB) pump than in a polyethylene bearing (PB) pump and statistically higher than the BioMedicus Pump (BP-80) on ΔP of 140 mm Hg. When the ΔP was at 330 mm Hg, a comparison between the three types of pumps revealed no difference in NIH. In addition, the primary vane of the impeller was redesigned to obtain an atraumatic structure. In the second study (n = 14), there was no difference in the NIH between BP-80 and the current model when the A/⁵ was 300 mm Hg (0.019 ± 0.002 vs. 0.027 ± 0.006, p = 0.3) and/or when the A/¹ was 100 mm Hg (0.0008 ± 0.0001 vs. 0.0014 ± 0.0002, p = 0.07). The modified pivot bearing had an improved spinning condition and no change in hemolysis. A proper selection of pivot bearing materials is important to develop an atraumatic centrifugal pump. The modification of the bearing system and redesign of the vane enabled a compact centrifugal pump to become a reality.     

Blood Trauma Testing of CentriMag and RotaFlow Centrifugal Flow Devices: A Pilot Study

Mechanical circulatory assist devices that provide temporary support in heart failure patients are needed to enable recovery or provide a bridge to decision. Minimizing risk of blood damage (i.e., hemolysis) with these devices is critical, especially if the length of support needs to be extended. Hematologic responses of the RotaFlow (Maquet) and CentriMag (Thoratec) temporary support devices were characterized in an in vitro feasibility study. Paired static mock flow loops primed with fresh bovine blood (700 mL, hematocrit [Hct] = 25 ± 3%, heparin titrated for activated clotting time >300 s) pooled from a single‐source donor were used to test hematologic responses to RotaFlow (n = 2) and CentriMag (n = 2) simultaneously. Pump differential pressures, temperature, and flow were maintained at 250 ± 10 mm Hg, 25 ± 2°C, and 4.2 ± 0.25 L/min, respectively. Blood samples (3 mL) were collected at 0, 60, 120, 180, 240, 300, and 360 min after starting pumps in accordance with recommended Food and Drug Administration and American Society for Testing and Materials guidelines. The CentriMag operated at a higher average pump speed (3425 rpm) than the RotaFlow (3000 rpm) while maintaining similar constant flow rates (4.2 L/min). Hematologic indicators of blood trauma (hemoglobin, Hct, platelet count, plasma free hemoglobin, and white blood cell) for all measured time points as well as normalized and modified indices of hemolysis were similar (RotaFlow: normalized index of hemolysis [NIH] = 0.021 ± 0.003 g/100 L, modified index of hemolysis [MIH] = 3.28 ± 0.52 mg/mg compared to CentriMag: NIH = 0.041 ± 0.010 g/100 L, MIH = 6.08 ± 1.45 mg/mg). In this feasibility study, the blood trauma performance of the RotaFlow was similar or better than the CentriMag device under clinically equivalent, worst‐case test conditions. The RotaFlow device may be a more cost‐effective alternative to the CentriMag.     

Comparison of Two Types of Neonatal Extracorporeal Life Support Systems With Pulsatile and Nonpulsatile Flow

We compared the effects of two neonatal extracorporeal life support (ECLS) systems on circuit pressures and surplus hemodynamic energy levels in a simulated ECLS model. The clinical set‐up included the Jostra HL‐20 heart–lung machine, either the Medtronic ECMO (0800) or the MEDOS 800LT systems with company‐provided circuit components, a 10 Fr arterial cannula, and a pseudo‐patient. We tested the system in nonpulsatile and pulsatile flow modes at two flow rates using a 40/60 glycerin/water blood analog, for a total of 48 trials, with n = 6 for each set‐up. The pressure drops over the Medtronic ECLS were significantly higher than those over the MEDOS system regardless of the flow rate or perfusion mode (144.8 ± 0.2 mm Hg vs. 35.7 ± 0.2 mm Hg, respectively, at 500 mL/min in nonpulsatile mode, P < 0.001). The preoxygenator mean arterial pressures were significantly increased and the precannula hemodynamic energy values were decreased with the Medtronic ECLS circuit. These results suggest that the MEDOS ECLS circuit better transmits hemodynamic energy to the patient, keeps mean circuit pressures lower, and has lower pressure drops than the Medtronic Circuit.     

Comparison of perfusion values after percutaneous transluminal angioplasty according to the severity of ischaemia in the diabetic foot

Percutaneous transluminal angioplasty (PTA) is now more frequently used to improve tissue perfusion in ischemic diabetic feet. However, there are concerns about its feasibility and effectiveness in severely ischaemic feet. This study aimed to compare the perfusion values after PTA according to the ischaemic degree of diabetic feet. This study included 133 ischaemic diabetic feet. The foot transcutaneous oxygen pressure (TcPO₂) and toe pressure were measured before the procedure and every second postoperative week for 6 weeks. The patients were divided into three groups according to ischaemic severity on the basis of TcPO₂ and toe pressures. In the “severely ischaemic” group, the TcPO₂ increased from 7.5 ± 4.9 to 40.3 ± 11.3 mm Hg (5.4‐fold) 6 weeks after the PTA (P < 0.001). The toe pressure increased from 8.5 ± 8.8 to 42.2 ± 19.3 mm Hg (5.0‐fold, P < 0.001). In the “mild” group, the TcPO₂ increased from 35.4 ± 2.5 to 41.8 ± 12.4 mm Hg (1.2‐fold, P = 0.003), and the toe pressure increased from 45.7 ± 12.3 to 54.3 ± 31.3 mm Hg (1.2‐fold, P > 0.05). Results of the “intermediate” group were in between. The most severely ischaemic group had the most dramatic increase of tissue perfusion after PTA. As such, PTA can be an effective method for increasing tissue perfusion even in the severely ischaemic diabetic feet.     

Hemodynamic Maladjustment and Disease Progression in Nephrosis with FSGS

Idiopathic nephrotic syndrome (NS) associated with focal segmental glomerulosclerosis (FSGS) and severe renal function impairment is usually refractory to the conventional treatment and progresses to end‐stage renal disease. Herein, we reported 10 patients with NS‐FSGS who had initially had CCr 34 ± 12 mL/min/1.73m² (normal 120 mL/min/1.73m²), FE Mg 7.8 ± 2.6% (normal 2.2%), 24‐h urinary protein 3.1 g (normal < 200 mg) and been followed up for over 10 years. The initial intrarenal hemodynamic study revealed a marked elevation of efferent arteriolar resistance (RE 17289 ± 8636 dyne.s.cm^{? 5}; normal 3000 dyne.s.cm^{? 5}), intraglomerular hypertension (PG 57 ± 1 mm Hg; normal 52 mm Hg), hyperfiltration (FF 0.24; normal 0.2), marked reductions in GFR 35 ± 17 mL/min/1.73m², renal plasma flow (RPF 159 ± 61 mL/min/1.73m²; normal 600 mL/min/1.73m²) and peritubular capillary flow (PTCF 123 ± 57 mL/min/1.73m²; normal 480 mL/min/1.73m²). Such a hemodynamic alteration indicated a hemodynamic maladjustment with a preferential constriction at RE. Treatment consists of multidrugs, namely angiotensin converting enzyme inhibitor, calcium channel blocker, antiplatelet and anticoagulant, with or without angiotensin II receptor antagonist. Following the treatment, correction of hemodynamic maladjustment has been achieved which is characterized by reductions in RE 6046 ± 2191 dyne.s.cm^{? 5}, PG 52 ± mm Hg, FF 0.19 ± 0.1 and increments in RPF 341 ± 118 mL/min/1.73m², PTCF 280 ± 106 mL/min/1.73m² and GFR 64 ± 17 mL/min/1.73m². Coinciding with hemodynamic improvement, there has been a steadily increased creatinine clearance and improvement in FE Mg 4.3 ± 2.6% and suppression of proteinuria 0.29 ± 0.4g/24 h after the period of follow‐up of greater than 10 years.     

Effect of the Pulsatile Extracorporeal Membrane Oxygenation on Hemodynamic Energy and Systemic Microcirculation in a Piglet Model of Acute Cardiac Failure

The objective of this study was to compare the effects of pulsatile and nonpulsatile extracorporeal membrane oxygenation (ECMO) on hemodynamic energy and systemic microcirculation in an acute cardiac failure model in piglets. Fourteen piglets with a mean body weight of 6.08 ± 0.86 kg were divided into pulsatile (N = 7) and nonpulsatile (N = 7) ECMO groups. The experimental ECMO circuit consisted of a centrifugal pump, a membrane oxygenator, and a pneumatic pulsatile flow generator system developed in‐house. Nonpulsatile ECMO was initiated at a flow rate of 140 mL/kg/min for the first 30 min with normal heart beating, with rectal temperature maintained at 36°C. Ventricular fibrillation was then induced with a 3.5‐V alternating current to generate a cardiac dysfunction model. Using this model, we collected the data on pulsatile and nonpulsatile groups. The piglets were weaned off ECMO at the end of the experiment (180 min after ECMO was initiated). The animals did not receive blood transfusions, inotropic drugs, or vasoactive drugs. Blood samples were collected to measure hemoglobin, methemoglobin, blood gases, electrolytes, and lactic acid levels. Hemodynamic energy was calculated using the Shepard's energy equivalent pressure. Near‐infrared spectroscopy was used to monitor brain and kidney perfusion. The pulsatile ECMO group had a higher atrial pressure (systolic and mean), and significantly higher regional saturation at the brain level, than the nonpulsatile group (for both, P < 0.05). Additionally, the pulsatile ECMO group had higher methemoglobin levels within the normal range than the nonpulsatile group. Our study demonstrated that pulsatile ECMO produces significantly higher hemodynamic energy and improves systemic microcirculation, compared with nonpulsatile ECMO in acute cardiac failure.     

Liposome‐Encapsulated Hemoglobin Accelerates Bronchial Healing After Pneumonectomy in the Rat With or Without Preoperative Radiotherapy

Liposome‐encapsulated hemoglobin (LEH) has been reported to accelerate wound healing in the stomach and skin in an experimental setting. LEH was tested in bronchial anastomotic healing after radiation and pneumonectomy in the rat. Sprague‐Dawley rats (n = 61) received preoperative radiation (20 Gy) to the chest and underwent left pneumonectomy with bronchial stump closure using the Sweet method 4 days later, when they were randomized to receive intravenous infusion of LEH with high O₂ affinity (P₅₀O₂ = 17 mm Hg, 10 mL/kg, n = 32) or saline (n = 29). Additional rats (n = 18) were treated in the same way without preoperative radiation. Bronchial anastomotic healing was evaluated 2 days after surgery by determining the bursting pressure and infiltration of neutrophils, monocytes, and macrophages. Bronchial bursting pressure was elevated in the rats receiving LEH both in the unirradiated group (LEH 212 ± 78 vs. saline 135 ± 63 mm Hg, P < 0.05) and in rats with preoperative radiation (LEH 162 ± 48 vs. saline 116 ± 56 mm Hg, P < 0.01). Moreover, the percentage of rats with bursting pressure <100 mm Hg tended to be smaller in the unirradiated group (LEH 1/9 [11.1%] vs. saline 4/9 [44.4%], NS) and was significantly reduced in irradiated animals (LEH 3/32 [9.4%] vs. saline 11/29 [38%], P < 0.05). There were no morphological differences except for macrophage infiltration to the anastomotic area, which was significantly prominent in the LEH‐treated rats (P < 0.05) regardless of the presence or absence of preoperative irradiation (IR). The results suggest that LEH with high O₂ affinity may improve mechanical strength and morphological findings in bronchial anastomosis in rats regardless of the presence or absence of preoperative IR. The irradiated rats later treated with LEH had equivalent or better bronchial healing than that of saline‐treated naïve animals undergoing pneumonectomy alone.     

Functional Diagnostic Parameters for Arteriovenous Fistula

The inability to detect the arteriovenous fistula (AVF) dysfunction in a timely manner under the current surveillance programs, which are based on either diameter (d), flow rate (Q), or pressure (p) measurements, is one of the major challenges of dialysis treatment. Thus, our aim is to introduce new functional diagnostic parameters that can better predict AVF functionality status. Six AVFs were created between the femoral arteries and veins of three pigs, each pig having two AVFs on either limb. Flow fields and pressure drop (Δp) in AVFs were obtained via numerical analysis utilizing the CT scan and Doppler ultrasound data at 2D (D: days), 7D, and 28D postsurgery. The dataset included 16 (two pigs [four AVFs] for three time points, and one pig [two AVFs] for two time points) repeated measurements over time, and the statistical analysis was done using a mixed model. To evaluate the nature of pressure drop–flow relationships in AVFs, the Δp was correlated with the average velocity at proximal artery (v) and also the corresponding scaled velocity (v*) by the curvature ratio of anastomotic segment. Based on these relationships, two new functional diagnostic parameters, including the nonlinear pressure drop coefficient (C_p; pressure drop divided by dynamic pressure at proximal artery) and the linear resistance index (R; pressure drop divided by velocity at proximal artery), were introduced. The diagnostic parameters that were calculated based on scaled velocity are represented as R* and C_p*. A marginal (P = 0.1) increase in d from 2D (5.4 ± 0.7 mm) to 7D (6.8 ± 0.7 mm), along with a significant increase in Q (2D: 967 ± 273 mL/min; 7D: 1943 ± 273 mL/min), was accompanied by an almost unchanged Δp over this time period (2D: 16.42 ± 4.6 mm Hg; 7D: 16.40 ± 4.6 mm Hg). However, the insignificant increase in d and Q from 7D to 28D (d = 7.8 ± 0.8 mm; Q = 2181 ± 378 mL/min) was accompanied by the elevation in Δp (24.6 ± 6.5 mm Hg). The functional diagnostic parameters, R and C_p, decreased from 2D (R = 22.4 ± 2.8 mm Hg/m/s; C_p = 12.0 ± 2.6) to 7D (R = 20.8 ± 2.8 mm Hg/m/s; C_p = 8.1 ± 2.6), and then increased from 7D to 28D (R = 35.5 ± 5.7 mm Hg/m/s; C_p = 17.5 ± 3.6) with a marginal significance. However, when the scaled velocity was used to calculate R* and C_p*, the increase in diagnostic parameters from 7D to 28D achieved statistical significance (P < 0.05). In summary, although the differences in the hemodynamic parameters (d, Q, and Δp) from 7D to 28D were insignificant, changes in their combined effects in the form of diagnostic parameters were significant. Therefore, the functional diagnostic parameters are capable of better distinguishing changes in the hemodynamic variations, and thus, could be promising endpoints to diagnose the functionality of AVFs over time.     

Synchronized Pulsatile Flow With Low Systolic Output From Veno‐Arterial Extracorporeal Membrane Oxygenation Improves Myocardial Recovery After Experimental Cardiac Arrest in Pigs

Circulatory failure following cardiac arrest (CA) requires catecholamine support and occasionally veno‐arterial extracorporeal membrane oxygenation (vaECMO). VaECMO‐generated blood flow is continuous and retrograde, increasing ventricular stroke work. Our aim was to assess the benefit of a device generating a pulsatile vaECMO flow synchronized with the heart rhythm lowering systolic vaECMO output on the left ventricular ejection fraction (LVEF) and pulmonary capillary pressure (Pcap) after CA. This experimental randomized study in pigs compared standard nonpulsatile vaECMO (control) with pulsatile synchronized vaECMO (study) group using a pulsatility‐generating device. After sedation and intubation, ventricular fibrillation was induced by pacing. After 10‐min ventricular fibrillation, cardiopulmonary resuscitation was performed for 20 min then vaECMO, defibrillation and 0.15 µg/kg/min intravenous epinephrine infusion were initiated. Hemodynamics, Pcap, LVEF by echocardiography and angiography were measured at baseline and every 30 min after the vaECMO start until vaECMO and epinephrine were stopped (at 120 min), and 30 min later. Baseline hemodynamics did not differ between groups; 120 min after vaECMO initiation, LVEF by echocardiography and angiography was significantly higher in the study than control group 55 ± 19% versus 34 ± 13% (P = 0.042), 50 ± 16% versus 33 ± 12% (P = 0.043), respectively. Pcap decreased from baseline by 4.2 ± 8.6 mm Hg in the study group but increased by 5.6 ± 5.9 mm Hg in the control group (P = 0.043). Thirty minutes later, LVEF remained higher in the study group 44 ± 7% versus 26 ± 11% (P = 0.008) while Pcap did not differ. A synchronized pulsatile device decreasing systolic output from vaECMO improved LVEF and Pcap in a pig model of CA and resuscitation.     

Managing Traps and Pitfalls During Initial Steps of an ECMO Retrieval Program Using a Miniaturized Portable System: What Have We Learned From the First Two Years?

The aim of this study was to provide early and mid‐term results of the newly established extracorporeal membrane oxygenation (ECMO) retrieval service in a tertiary cardiothoracic center using the miniaturized portable Cardiohelp System (Maquet, Rastatt, Germany). A particular attention was paid to organizational and logistic specifics as well as challenges and pitfalls associated with initial phase of the program. From January 2015 until January 2017 a heterogenic group of 28 consecutive patients underwent ECMO implantation in distant hospitals for acute cardiac, pulmonary or combined failure as a bridge‐to‐decision and were subsequently transported to our institution. Each cannulation was performed bedside on intensive care units (ICU) using the Seldinger's technique. Early outcomes and mid‐term overall survival with up to two‐year follow‐up along with the impact of ongoing cardiopulmonary resuscitation (CPR) on outcome were presented. Also, changes in hemodynamics and tissue perfusion factors 24 h after ECMO implantation were evaluated. ECMO implantations were performed in 15 distant departments with the median distance of 23(10;40) (maximum 60) km. A total of 15 patients (54%) were cannulated under CPR with the median duration of 30(20;110) (maximum 180) min. After 24 h of support there were significant improvements in SvO₂ (P = 0.021), mean arterial pressure (P = 0.027), FiO₂ (P = 0.001), lactate (P = 0.001), and pH (P < 0.001). The mean ECMO support duration was 96 ± 100 (maximum 384) hours, whereas 11 patients (40%) were weaned off support and discharged from hospital. Overall cumulative survival in patients without the need for CPR was 61.5% at one week and 38.5% at 1 month, 6 month, and 1 year, whereas patients requiring CPR survived in 40% at one week, and 33.3% at 1 month, 6 month, and 1 year (Log‐Rank (Mantel‐Cox) P = 0.374, Breslow (Generalized Wilcoxon) P = 0.162). Our initial experience shows that launching new ECMO retrieval programs in centers with sufficient ICU capacities and local ECMO experience can be feasible and associated with acceptable “real world” results despite the initial learning curve. Rapid logistical organization and team flexibility are the key points to ensure comparable survival of patients requiring prolonged CPR.     

Comparison of Coagulation Parameters,Anticoagulation, and Need for Transfusion in Patients on Interventional Lung Assist or Veno‐Venous Extracorporeal Membrane Oxygenation

Clinical data on anticoagulation needs of modern extracorporeal membrane oxygenation (ECMO) and its impact on coagulation are scarce. Therefore, we analyzed coagulation‐related parameters, need for transfusion, and management of anticoagulation in adult patients with severe acute respiratory failure during treatment with either pumpless interventional lung assist (iLA) or veno‐venous ECMO (vv‐ECMO). Sixty‐three patients treated with iLA and 192 patients treated with vv‐ECMO at Regensburg University Hospital between January 2005 and May 2011 were analyzed. Data related to anticoagulation, transfusion, and coagulation parameters were collected prospectively by the Regensburg ECMO registry. Except for a higher, sequential organ failure assessment (SOFA) score in the ECMO group (12 [9–15] vs. 11 [7–14], P = 0.007), a better oxygenation, and a lower dosage of vasopressors in the iLA patients, both groups had similar baseline characteristics. No difference was noted in terms of outcome and overall transfusion requirements. Factors of the plasmatic coagulation system were only marginally altered over time and did not differ between groups. Platelet counts in ECMO‐treated patients, but not in those treated with iLA, dropped significantly during extracorporeal support. A more intense systemic anticoagulation with a mean activated partial thromboplastin time (aPTT) > 53 s led to a higher need for transfusions compared with the group with a mean aPTT < 53 s, whereas the average durability of membrane oxygenators was not affected. Need for red blood cell (RBC) transfusion was highest in patients with extrapulmonary sepsis (257 mL/day), and was significantly lower in primary pulmonary adult respiratory distress syndrome (ARDS) (102 mL/day). Overall, 110 (0–274) mL RBC was transfused in the ECMO group versus 146 (41–227) mL in the iLA group per day on support. The impact of modern iLA and ECMO systems on coagulation allows comparatively safe long‐term treatment of adult patients with acute respiratory failure. A moderate systemic anticoagulation seems to be sufficient. Importantly, platelets are more affected by vv‐ECMO compared with pumpless iLA.     

Variations in Aortic Pressure Affect the Mechanics of the Intra‐Aortic Balloon: An In Vitro Investigation

This study aims to investigate the mechanics of the intra‐aortic balloon (IAB) under different aortic pressure (P_ao) and inclination (0–75°). Pressure and flow were measured in an artificial aorta during IAB pumping with a frequency of 1:3. Volume displaced toward the “coronary arteries” during inflation (V_prox) and “intra‐aortic” pressure reduction during deflation (P_r) were derived. IAB duration of inflation and deflation was determined with a high‐speed camera visualization. When the aorta was horizontal, P_ao raised from 45 mm Hg to 115 mm Hg, V_prox reduced by 18% (25.0 ± 1.0 mL vs. 30.4 ± 1.9 mL) and P_r increased by 117% (106.4 ± 0.3 mm Hg vs. 48.9 ± 0.6 mm Hg). When the aorta was inclined, at low P_ao of 45 mm Hg, V_prox was reduced by 30% from 0° to 45° (19.8 ± 2.3 mL vs. 28.3 ± 1.7 mL) and P_r was reduced by 66% (16.5 ± 0.1 mm Hg vs. 48.9 ± 0.6 mm Hg). However, at high P_ao of 115 mm Hg, V_prox remained unchanged with increasing angle (20.0 ± 1.0 mL) and P_r was reduced by 24% (80.6 ± 0.8 mm Hg vs. 106.4 ± 0.3 mm Hg). Increasing P_ao increased duration of inflation. At low P_ao, increasing angle resulted in increasing duration of inflation, but at high P_ao, increasing angle had the opposite effect. Duration of deflation generally decreased with P_ao and increased with increasing angle. The IAB pump is affected by both P_ao and angle, indicating that non‐normotensive patients or patients in the semi‐recumbent position might not receive the full benefits of IAB counterpulsation.     

Pulse Conductance and Flow‐induced Hemolysis During Pulsatile Cardiopulmonary Bypass

In this study, the hypothesis was tested that a low‐resistant, high‐compliant oxygenator provides better pulse conductance and less hemolysis than a high‐resistant, low‐compliant oxygenator during pulsatile cardiopulmonary bypass. Forty adults undergoing coronary artery bypass surgery were randomly divided into two groups using either an oxygenator with a relatively low hydraulic resistance (Quadrox BE‐HMO 2000, Maquet Cardiopulmonary AG, Hirrlingen, Germany) or with a relatively high hydraulic resistance (Capiox SX18, Terumo Cardiovascular Systems, Tokyo, Japan). The phase shift between the flow signals measured at the inlet and outlet of the oxygenator was used to assess compliance. Pulse conductance in terms of pressure attenuation was calculated by dividing the outlet pulse pressure of the oxygenator by the inlet pulse pressure. A normalized index was used to assess hemolysis. The phase shifts in time of the flow pulses were 36 ± 6 ms in the low‐resistant (high‐compliant) oxygenator, and 14 ± 2 ms in the high‐resistant (low‐compliant) oxygenator group (P < 0.001). The low‐resistant, high‐compliant oxygenator provided 27% better pulse conductance compared with the high‐resistant, low‐compliant oxygenator (0.84 ± 0.02 and 0.66 ± 0.01, respectively, P < 0.001). Inlet pulse pressures were significantly higher (29%) in the high‐resistant, low‐compliant (Capiox) group than in the low‐resistant, high‐compliant (Quadrox) group (838 ± 38 mm Hg and 648 ± 25 mm Hg respectively, P < 0.001), but no significant difference in hemolysis was found. A low‐resistant, high‐compliant oxygenator provides better pulse conduction than a high‐resistant, low‐compliant oxygenator. However, the study data could not confirm the association of high pressures with increased hemolysis.     

Acute Effects of Intermittent Hemodialysis and Sustained Low-Efficiency Hemodialysis (SLED) on the Pulmonary Function of Patients under Mechanical Ventilation

The effects of hemodialysis (HD) on pulmonary function are still controversial. The objective of this study was to evaluate the effect of intermittent hemodialysis (IHD) and sustained low-efficiency dialysis (SLED) on the respiratory mechanics of ICU patients under invasive mechanical ventilation. We prospectively studied 31 patients. Laboratory and respiratory evaluation (static and dynamic compliance and resistance) was performed pre- and post-HD. Forty HD sessions were studied and grouped in: SLED (n?=?17; Qa?=?200–250 mL/min, Qd?=?300 mL/min) and IHD (n?=?23; Qa =?250–300 mL/min, Qd?=?500 mL/min). There was no difference between the groups according to age, gender, comorbidities, APACHE II, and cause of mechanical ventilation, but pre-HD, patients in the IHD group had higher levels of plasma creatinine (5.4 ± 2.0 vs. 4.2 ± 1.3 mg/dL, p = 0.048) and platelets (286 ± 186 vs. 174 ± 95 10³/mm², p = 0.032) and lower arterial pH (7.37 ± 0.07 vs. 7.42 ± 0.05, p = 0.02). The efficiency of the treatment was similar (p > 0.05) with both types of HD regarding fluid removal, urea reduction rate, and decrease in plasma creatinine. Pre-HD, the ventilatory conditions of both groups were similar (p > 0.05) except for pressure support ventilation and airflow resistance. There were no changes (pre- versus post-HD p > 0.05) induced either by IHD or SLED in the ratio PaO₂/FiO₂ or in any measured ventilatory parameter. In conclusion, neither IHD nor SLED modifies the pulmonary function of patients under mechanical ventilation.     

Influence of a Rotational Speed Modulation System Used With an Implantable Continuous‐Flow Left Ventricular Assist Device on von Willebrand Factor Dynamics

We have developed a rotational speed (RS) modulation system for a continuous‐flow left ventricular assist device (EVAHEART) that can change RS in synchronization with a patient's electrocardiogram. Although EVAHEART is considered not to cause significant acquired von Willebrand syndrome, there remains a concern that the repeated acceleration and deceleration of the impeller may degrade von Willebrand factor (vWF) multimers. Accordingly, we evaluated the influence of our RS modulation system on vWF dynamics. A simple mock circulation was used. The circulation was filled with whole bovine blood (650 mL), and the temperature was maintained at 37 ± 1°C. EVAHEART was operated using the electrocardiogram‐synchronized RS modulation system with an RS variance of 500 rpm and a pulse frequency of 60 bpm (EVA‐RSM; n = 4). The pumps were operated at a mean flow rate of 5.0 ± 0.2 L/min against a mean pressure head of 100 ± 3 mm Hg. The continuous‐flow mode of EVAHEART (EVA‐C; n = 4) and ROTAFLOW (ROTA; n = 4) was used as controls. Whole blood samples were collected at baseline and every 60 min for 6 h. Complete blood counts (CBCs), normalized indexes of hemolysis (NIH), vWF antigen (vWF:Ag), vWF ristocetin cofactor (vWF:Rco), the ratio of vWF:Rco to vWF:Ag (Rco/Ag), and high molecular weight multimers (HMWM) of vWF were evaluated. There were no significant changes in CBCs throughout the 6‐h test period in any group. NIH levels of EVA‐RSM, EVA‐C, and ROTA were 0.0035 ± 0.0018, 0.0031 ± 0.0007, and 0.0022 ± 0.0011 g/100 L, respectively. Levels of vWF:Ag, vWF:Rco, and Rco/Ag did not change significantly during the test. Immunoblotting analysis of vWF multimers showed slight degradation of HMWM in all groups, but there were no significant differences between groups in the ratios of HMWM to low molecular weight multimers, calculated by densitometry. This study suggests that our RS modulation system used with EVAHEART does not have marked adverse influences on vWF dynamics. The low NIH and the absence of significant decreases in CBCs indicate that EVAHEART is hemocompatible, regardless of whether it is operated with the RS modulation system.     

Irinotecan injures tight junction and causes bacterial translocation in rat

BackgroundThe objective of this study was to evaluate the efficacy of resuscitative endovascular aortic balloon occlusion (REBOA) of the distal aorta in a porcine model of pelvic hemorrhage.MethodsSwine were entered into three phases of study: injury (iliac artery), hemorrhage (45 s), and intervention (180 min). Three groups were studied: no intervention (NI, n = 7), a kaolin-impregnated gauze (Combat Gauze) (CG, n = 7), or REBOA (n = 7). The protocol was repeated with a dilutional coagulopathy (CG-C, n = 7, and REBOA-C, n = 7). Measures of physiology, rates of hemorrhage, and mortality were recorded.ResultsRate of hemorrhage was greatest in the NI group, followed by the REBOA and CG groups (822 ± 415 mL/min versus 11 ± 13 and 0.2 ± 0.4 mL/min respectively; P < 0.001). MAP following intervention (at 15 min) was the same in the CG and REBOA groups and higher than in the NI group (70 ± 4 and 70 ± 11 mm Hg versus 5 ± 13 mm Hg respectively; P < 0.001). There was 100% mortality in the NI group, with no deaths in the CG or REBOA group. In the setting of coagulopathy, the rate of bleeding was higher in the CG-C versus the REBOA-C group (229 ± 295 mL/min versus 20 ± 7 mL/min, P = 0.085). MAP following intervention (15 min) was higher in the REBOA-C than the CG-C group (71 ± 12 mm Hg versus 28 ± 31 mm Hg; P = 0.005). There were 5 deaths (71.4%) in the CG-C group, but none in the REBOA-C group (P = 0.010).ConclusionBalloon occlusion of the aorta is an effective method to control pelvic arterial hemorrhage. This technique should be further developed as an adjunct to manage noncompressible pelvic hemorrhage.