Dirk Lunz

Cardiac decompression on extracorporeal life support: a review and discussion of the literature.

Extracorporeal life support is a worldwide expanding technology for patients in critical cardiogenic shock. The device is usually attached to the femoral vessels using percutaneous techniques. Despite sufficient extracorporeal circulatory support, an unclear number of patients develop high end-diastolic pressures leading to left ventricular distension and pulmonary edema, and ventricular thrombus formation may evolve. This article discusses the strategies to prevent ventricular distension by conservative, interventional, and surgical means, also illustrated by case presentations.

Technical Complications during Veno-Venous Extracorporeal Membrane Oxygenation and Their Relevance Predicting a System-Exchange – Retrospective Analysis of 265 Cases

Objectives Technical complications are a known hazard in veno-venous extracorporeal membrane oxygenation (vvECMO). Identifying these complications and predictive factors indicating a developing system-exchange was the goal of the study. Methods Retrospective study on prospectively collected data of technical complications including 265 adult patients (Regensburg ECMO Registry, 2009-2013) with acute respiratory failure treated with vvECMO. Alterations in blood flow resistance, gas transfer capability, hemolysis, coagulation and hemostasis parameters were evaluated in conjunction with a system-exchange in all patients with at least one exchange (n = 83). Results Values presented as median (interquartile range). Patient age was 50(36–60) years, the SOFA score 11(8–14.3) and the Murray lung injury Score 3.33(3.3–3.7). Cumulative ECMO support time 3411 days, 9(6–15) days per patient. Mechanical failure of the blood pump (n = 5), MO (n = 2) or cannula (n = 1) accounted for 10% of the exchanges. Acute clot formation within the pump head (visible clots, increase in plasma free hemoglobin (frHb), serum lactate dehydrogenase (LDH), n = 13) and MO (increase in pressure drop across the MO, n = 16) required an urgent system-exchange, of which nearly 50% could be foreseen by measuring the parameters mentioned below. Reasons for an elective system-exchange were worsening of gas transfer capability (n = 10) and device-related coagulation disorders (n = 32), either local fibrinolysis in the MO due to clot formation (increased D-dimers [DD]), decreased platelet count; n = 24), or device-induced hyperfibrinolysis (increased DD, decreased fibrinogen [FG], decreased platelet count, diffuse bleeding tendency; n = 8), which could be reversed after system-exchange. Four MOs were exchanged due to suspicion of infection. Conclusions The majority of ECMO system-exchanges could be predicted by regular inspection of the complete ECMO circuit, evaluation of gas exchange, pressure drop across the MO and laboratory parameters (DD, FG, platelets, LDH, frHb). These parameters should be monitored in the daily routine to reduce the risk of unexpected ECMO failure.

Cardiac effects of induction agents in the septic rat heart

IntroductionThe current debate about the side effects of induction agents, e.g. possible adrenal suppression through etomidate, emphasizes the relevance of choosing the correct induction agent in septic patients. However, cardiovascular depression is still the most prominent adverse effect of these agents, and might be especially hazardous in septic patients presenting with a biventricular cardiac dysfunction - or so-called septic cardiomyopathy. Therefore, we tested the dose-response direct cardiac effects of clinically available induction agents in an isolated septic rat heart model.MethodsA polymicrobial sepsis was induced via cecal ligation and single puncture. Hearts (n = 50) were isolated and randomly assigned to five groups, each receiving etomidate, s(+)-ketamine, midazolam, propofol, or methohexitone at concentrations of 1 × 10-8 to 1 × 10-4 M. Left ventricular pressure, contractility and lusitropy, and coronary flow were measured. Cardiac work, myocardial oxygen delivery, oxygen consumption, and percentage of oxygen extraction were calculated.ResultsAll of the induction agents tested showed a dose-dependent depression of cardiac work. Maximal cardiac work dysfunction occurred in the rank order of s(+)-ketamine (-6%) <etomidate (-17%) <methohexitone (-31%) <midazolam (-38%) <propofol (-50%). In addition, propofol showed a maximum decrease in contractility of -38%, a reduction in lusitropy of -44%, and a direct vasodilator effect by increasing coronary flow by +29%.ConclusionsOverall, this study demonstrates that these tested drugs indeed have differential direct cardiac effects in the isolated septic heart. Propofol showed the most pronounced adverse direct cardiac effects. In contrast, S(+)ketamine showed cardiovascular stability over a wide range of concentrations, and might therefore be a beneficial alternative to etomidate.

Extracorporeal membrane oxygenation by single-vessel access in adults: advantages and limitations.

Veno-venous extracorporeal membrane oxygenation (vvECMO) conventionally requires the cannulation of two vessels. Here we report our initial experience with the “Wang-Zwische” (WZ) double-lumen cannula. In a group of n = 36 patients single venous cannulation for vvECMO was performed. A retrospective analysis was executed. A comparison of flow characteristics to standard two-vessel cannulation was performed. Mean age of the patient population was 48 ± 15 years (body mass index [BMI] 32 ± 13 kg/m2). In n = 32 patients (89%) the cannula was implanted percutaneously under echo or fluoroscopic guidance in less than 30 minutes. Nine patients were partially mobilized on extracorporeal membrane oxygenation (ECMO) support. Oxygenation (partial arterial oxygen tension [PaO2]/fraction of inspired oxygen [FiO2]) improved significantly in all patients from 66 mm Hg (interquartile range [IQR] 58–87 mm Hg) before ECMO to 117 mm Hg (IQR 95–195 mm Hg, p = 0.001) after 24 hours. In seven patients (19%) nonfatal adverse events occurred, including three dislocations, two partial cannula thrombosis, one ventricular perforation, and one retroperitoneal hemorrhage. The negative pressures for drainage at a flow of 2.5 L/min were significantly lower in a standard (S) two-vessel approach compared with a WZ approach (S: −9 mm Hg; IQR −3 to −24 mm Hg, vs. WZ: −23 mm Hg; IQR −4 to −40 mm Hg; p = 0.04). The WZ cannula offers sufficient gas exchange in addition to certain advantages over standard cannulation, including facilitated cannulation in selected patients and improved mobilization.

Emergency and prophylactic use of miniaturized veno-arterial extracorporeal membrane oxygenation in transcatheter aortic valve implantation

To report our centers experience using veno‐arterial extracorporeal membrane oxygenation (vaECMO) in transcatheter aortic valve implantation (TAVI).

Technical-Induced Hemolysis in Patients with Respiratory Failure Supported with Veno-Venous ECMO – Prevalence and Risk Factors

The aim of the study was to explore the prevalence and risk factors for technical-induced hemolysis in adults supported with veno-venous extracorporeal membrane oxygenation (vvECMO) and to analyze the effect of hemolytic episodes on outcome. This was a retrospective, single-center study that included 318 adult patients (Regensburg ECMO Registry, 2009–2014) with acute respiratory failure treated with different modern miniaturized ECMO systems. Free plasma hemoglobin (fHb) was used as indicator for hemolysis. Throughout a cumulative support duration of 4,142 days on ECMO only 1.7% of the fHb levels were above a critical value of 500 mg/l. A grave rise in fHb indicated pumphead thrombosis (n = 8), while acute oxygenator thrombosis (n = 15) did not affect fHb. Replacement of the pumphead normalized fHb within two days. Neither pump or cannula type nor duration on the first system was associated with hemolysis. Multiple trauma, need for kidney replacement therapy, increased daily red blood cell transfusion requirements, and high blood flow (3.0–4.5 L/min) through small-sized cannulas significantly resulted in augmented blood cell trauma. Survivors were characterized by lower peak levels of fHb [90 (60, 142) mg/l] in comparison to non-survivors [148 (91, 256) mg/l, p≤0.001]. In conclusion, marked hemolysis is not common in vvECMO with modern devices. Clinically obvious hemolysis often is caused by pumphead thrombosis. High flow velocity through small cannulas may also cause technical-induced hemolysis. In patients who developed lung failure due to trauma, fHb was elevated independantly of ECMO. In our cohort, the occurance of hemolysis was associated with increased mortality.

First experience with the deltastream® DP3 in venovenous extracorporeal membrane oxygenation and air-supported inter-hospital transport

OBJECTIVES Based on continuous technical innovations and recent research, extracorporeal membrane oxygenation (ECMO) has become a promising tool in the treatment of patients with acute (cardio)pulmonary failure. Nevertheless, any extracorporeal technique requires a high degree of experience and knowledge, so that a restriction to specialized centres seems to be reasonable. As a consequence of this demand, the need for inter-hospital transfer of patients with severely impaired (cardio)pulmonary function is rising. Unfortunately, most of the ECMO devices used in the clinical setting are not suitable for inter-hospital transport because of their size, weight or complexity. In this article, we describe our first experiences with the airborne transport of 6 patients on a new portable, miniaturized and lightweight extracorporeal circulation system, the Medos deltastream® DP3. METHODS Six patients suffering acute respiratory failure were taken on venovenous ECMO (DP3) out-of-centre and transferred to the University Medical Center Regensburg by helicopter. All cardiorespiratory-relevant parameters of the patients and the technical functioning of the device were continuously monitored and documented. RESULTS Implantation of the device and air-supported transport were performed without any technical complications. The patients were transported from a distance of 66-178 km, requiring a time of 40-120 min. With the help of the new deltastream® DP3 ECMO device, a prompt stabilization of the cardiopulmonary function could be achieved in all patients. One patient was under ongoing cardiopulmonary resuscitation by the time our ECMO team arrived at the peripheral hospital and died shortly after arrival in the central emergency ward. CONCLUSIONS Our experience shows that the deltastream® DP3 is an absolutely reliable and safe ECMO device that could gain growing importance in the field of airborne transportation of patients on ECMO due to its unsophisticated, miniaturized and lightweight characteristics.

Single‐Center Experience With Extracorporeal Life Support in 103 Nonpostcardiotomy Patients

Extracorporeal membrane oxygenation (ECMO) has been successfully used to support patients with cardiac arrest failing to respond to conventional cardiopulmonary resuscitation (CPR). Preimplant factors being indicative for success are unknown up to now. The study describes single center experience with special focus on differences between survivors and nonsurvivors. Between 2002 and 2009, 103 patients were supported within the scope of CPR by means of ECMO. Besides primary diagnosis, duration, and outcome, pH, lactate, mean arterial pressure, aspartate aminotransferase, bilirubin, catecholamine dosage, and oxygenation ratio before ECMO, after 2 h, 1 day, and at explantation were analyzed. One hundred three patients (51.2 ± 16 years, 35 women, 68 men) were analyzed. Primary cardiac failure led to CPR in 54%. Duration of support was 4.8 ± 0.6 days. Twenty-nine (28.1%) patients survived to hospital discharge. On ECMO support, pH, lactate, and mean arterial pressure improved significantly. Catecholamine dosage was significantly reduced after ECMO implantation. Demographic data and primary diagnosis revealed no significant influence on outcome. pH, lactate, creatinine, and bilirubin differed significantly between survivors and nonsurvivors in the course of ECMO support. ECMO support during CPR reliably improves the circulatory and respiratory situation. Considering observed survival critical patient selection is mandatory. Although there are several significant differences between surviving patients and patients with fatal outcome, patient selection turns out to be difficult as clinically relevant factors show only limited predictive value. Future research should focus on better defining a population that may be best of all suited for the use of ECMO support in CPR.

Hemostatic Changes During Extracorporeal Membrane Oxygenation: A Prospective Randomized Clinical Trial Comparing Three Different Extracorporeal Membrane Oxygenation Systems.

Objective:Extracorporeal membrane oxygenation is a rescue therapy for patients with severe lung failure. Major complications caused by extracorporeal membrane oxygenation are bleeding, thrombosis, and hemolysis. The aim of this study was to compare the impact of different extracorporeal membrane oxygenation systems on blood hemostasis in adults during veno-venous extracorporeal membrane oxygenation therapy. Design:Single center prospective randomized study. Setting:University Hospital Regensburg, Germany. Patients:Adult patients with severe acute respiratory distress syndrome requiring veno-venous extracorporeal membrane oxygenation therapy. Interventions:None. Measurements and Main Results:Three different extracorporeal membrane oxygenation systems: the Cardiohelp system (Maquet Cardiopulmonary AG), the Dideco ECC.O5 (Sorin Group), and the Deltastream system with Hilite 7000 LT + DP3 pumphead (Medos Medizintechnik AG) were compared. Therefore hemostasis, anticoagulation, hemolysis, and inflammatory parameters were monitored. Of the 54 patients included in the study, 18 patients each were randomly assigned to the three different extracorporeal membrane oxygenation systems. Exclusion criteria were acute renal failure, trauma, and surgery within 2 days. The median time on veno-venous extracorporeal membrane oxygenation support was 13.5 days (4–70 d). Median platelet count had dropped from 220.5 G/L before extracorporeal membrane oxygenation therapy to a minimum of 133 G/L by the last day of extracorporeal membrane oxygenation support. During the first 5 days of extracorporeal membrane oxygenation therapy, prothrombin fragment 1.2 (F1.2) (1.36–2.4 µM), thrombin-antithrombin complex (14.5–50 µg/L), and D-dimers (6.00–27.0 mg/L) increased, whereas fibrinogen values dropped from 5.8 to 4.1 g/L. The three different extracorporeal membrane oxygenation systems did not show any differences with regard to hemostasis, anticoagulation, hemolysis, and inflammatory parameters within the first 5 days of extracorporeal membrane oxygenation therapy. Conclusions:Over time, miniaturized veno-venous extracorporeal membrane oxygenation therapy increasingly activates coagulation. The different types of membrane oxygenators and pumps did not significantly alter hemostasis.

Neuron-specific enolase serum levels predict severe neuronal injury after extracorporeal life support in resuscitation

OBJECTIVES Extracorporeal life support (ECLS) is a rescue option in critically ill patients. Since fast available and appropriate for respiratory and circulatory failure, it is frequently applied in resuscitation scenarios. Neurological injury is a complication common in ECLS patients limiting outcome, particularly after resuscitation. In this study, the institutional ECLS database was used to correlate neuron-specific enolase (NSE) serum peak values with outcome of patients supported with venoarterial (VA) ECLS during cardiopulmonary resuscitation (CPR). METHODS From January 2011 to August 2012, 31 patients were provided with a VA ECLS during CPR (external cardiac massage). Serum NSE peaks were monitored and correlated with neurological outcome and hospital mortality. Patients were divided into two groups with mild-to-moderate and high NSE levels (cut-off value 100 μg/l). RESULTS High NSE levels were seen in 7 patients (mean 218 ± 155 μg/l) and mild-to-moderate levels in 24 patients (50 ± 23 μg/l, P = 0.0001). Duration of extracoporeal support was comparable in both groups (6.3 ± 7.5 vs 5.0 ± 4.5 days, P = n.s.). Patients with mild-to-moderate NSE levels were significantly older than those with high NSE levels (58 ± 16 vs 44 ± 15 years, P = 0.02). Six patients with high NSE levels (86%) developed severe neurological complications. Though 4 patients could be weaned from extracorporeal support, hospital mortality was 86% (6 patients). In contrast, patients with mild-to-moderate NSE levels had a hospital mortality of 46% (11 patients). Eighteen patients (75%) could be weaned from the device, and incidence of major neurological events was 29% (6 patients) only. Serum pH and lactate levels before ECLS implantation were significantly lower in patients with mild-to-moderate NSE values (pH: 7.23 ± 0.04 vs 6.93 ± 0.12, P = 0.039; lactate: 106 ± 11 vs 161 ± 16 mg/l, P = 0.023). CONCLUSIONS High NSE serum levels after ECLS correspond to poor neurological outcome and considerable mortality. Therefore, early neuroimaging is reasonable for determining therapeutic strategies in patients with high NSE peaks after resuscitation and extracorporeal support.