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The contribution of veno-venous (VV) extracorporeal membrane oxygenation (ECMO) to systemic oxygen delivery is determined by the ratio of total extracorporeal blood flow (Q˙EC) to cardiac output (Q˙). Thermodilution-based measurements of Q˙ may be compromised by blood recirculating through the ECMO (recirculation fraction; Rf). We measured the effects of Q˙EC and Rf on classic thermodilution-based measurements of Q˙ in six anesthetized pigs. An ultrasound flow probe measured total aortic blood flow (Q˙A0) at the aortic root. Rf was quantified with the ultrasound dilution technique. Q˙EC was set to 0-125% of Q˙A0 and Q˙ was measured using a pulmonary artery catheter (PAC) in healthy and lung injured animals. PAC overestimated Q˙ (Q˙Pa) at all Q˙EC settings compared to Q˙A0. The mean bias between both methods was 2.1 L/min in healthy animals and 2.7 L/min after lung injury. The difference between Q˙Pa and Q˙A0 increased with an Q˙EC of 75-125%/Q˙A0 compared to QEC

Infarction-related cardiogenic shock is the most severe complication of an acute coronary syndrome, that still bears a high mortality up to 50 % and wastes a lot of resources of an intensive care unit, especially if extracorporeal assist devices are used.In contrast to the adverse short-term outcome, patients fare a surprisingly well in the long range, both for survival and quality of life. Same as for the acute disease, which needs specific cardiologic and intensive care measures, long-term follow-up care needs a lot of medical and lifestyle interventions and treatments to obtain the best possible result for the patients. Since there is good evidence for cardiologic therapies from randomized controlled trials, high quality data to treat long-term sequalae of the stay on intensive care unit, are sparse.Overall, follow-up care of survivors of infarction related cardiogenic shock includes the best available treatment of the coronary artery disease, intensified heart failure therapy of left and right heart dysfunction and evaluation for the risk of sudden cardiac death and treatment of sequelae of the intensive-care-unit stay.

Measurement of oxygen uptake (VO 2 ) and carbon dioxide removal (VCO 2 ) on membrane lungs (MLs) during extracorporeal membrane oxygenation (ECMO) provides potential for improved and safer therapy. Real-time monitoring of ML function and degradation, calculating caloric needs as well as cardiac output, and weaning algorithms are among the future possibilities. Our study compared the continuous measurement of the standalone Quantum Diagnostics System (QDS) with the published Measuring Energy Expenditure in ECMO patients (MEEP) approach, which calculates sequential VO 2 and VCO 2 values via blood gas analysis and a physiologic gas content model. Thirty-nine datasets were acquired during routine venovenous ECMO intensive care treatment and analyzed. VO 2 was clinically relevant underestimated via the blood-sided measurement of the QDS compared to the MEEP approach (mean difference -42.61 ml/min, limits of agreement [LoA] -2.49/-87.74 ml), which could be explained by the missing dissolved oxygen fraction of the QDS equation. Analysis of VCO 2 showed scattered values with wide limits of agreement (mean difference 54.95 ml/min, LoA 231.26/-121.40 ml/min) partly explainable by a calculation error of the QDS. We described potential confounders of gas-sided measurements in general which need further investigation and recommendations for enhanced devices.

Optimizing the positive end-expiratory pressure remains challenging for any clinician treating a patient with acute respiratory distress syndrome. This paper presents an approach to automate a PEEP titration maneuver and identify the best PEEP according to maximal compliance. The respiratory system was modeled by a single-compartment model, and parameters were estimated using multiple linear regression. A classifier identified the best PEEP using the scaled relative change in compliance between PEEP levels based on empirical data from previous manual PEEP titrations. An experimental system allows the in vivo testing of the automated PEEP titration, including additional safety measures. The complete system was tested in a single animal experiment and correctly identified the best PEEP. The introduced system is a step closer towards an automated, standardized PEEP optimization and closed-loop control of mechanical ventilation.

Cardiogenic shock as a complication of myocardial infarction (5-10%) increases the mortality of uncomplicated myocardial infarction from less than 10% to 40%. This is due to the development of multiple organ dysfunction syndrome triggered by the extensive shock-induced impairment of organ perfusion. Therefore, guideline-based treatment should not only be restricted to reopening of the occluded coronary artery and management of complications of the infarction: important for survival are also guideline-driven optimization of organ perfusion by inotropic and vasoactive substances and, with well-defined indications, by temporary mechanical circulatory support but not by intra-aortic counterpulsation. Equally important, however, are shock-specific intensive care measures to prevent or attenuate organ dysfunction, such as lung protective ventilation in cases where ventilation is obligatory.Der kardiogene Schock als Infarktkomplikation (5–10 %) erhöht die Sterblichkeit des unkomplizierten Herzinfarkts von weniger als 10 % auf etwa 40 %, bedingt durch die Entwicklung eines multiplen Organdysfunktionssyndroms infolge der hochgradigen schockbedingten Störung der Organperfusion. Demzufolge darf sich die leitlinienorientierte Therapie nicht nur auf die Wiedereröffnung des verschlossenen Koronargefäßes und auf die Behandlung von Infarktkomplikationen beschränken. Wichtig für das Überleben ist auch die herzzeitvolumengesteuerte Optimierung der Organdurchblutung mittels inotroper und vasoaktiver Substanzen sowie – bei strenger Indikationsstellung – mit temporären mechanischen Unterstützungssystemen, nicht jedoch mit der intraaortalen Ballonpumpe. Ebenso wichtig sind schockspezifische intensivmedizinische Maßnahmen wie eine lungenprotektive Beatmung bei Beatmungspflichtigkeit.

Various animal models exist to study the complex pathomechanisms of the acute respiratory distress syndrome (ARDS). These models include pulmo-arterial infusion of oleic acid, infusion of endotoxins or bacteria, cecal ligation and puncture, various pneumonia models, lung ischemia/reperfusion models and, of course, surfactant depletion models, among others. Surfactant depletion produces a rapid, reproducible deterioration of pulmonary gas exchange and hemodynamics and can be induced in anesthetized pigs using repeated lung lavages with 0.9% saline (35 mL/kg body weight, 37 °C). The surfactant depletion model supports investigations with standard respiratory and hemodynamic monitoring with clinically applied devices. But the model suffers from a relatively high recruitability and ventilation with high airway pressures can immediately reduce the severity of the injury by reopening atelectatic lung areas. Thus, this model is not suitable for investigations of ventilator regimes that use high airway pressures. A combination of surfactant depletion and injurious ventilation with high tidal volume/low positive end-expiratory pressure (high Tv/low PEEP) to cause ventilator induced lung injury (VILI) will reduce the recruitability of the resulting lung injury. The advantages of a timely induction and the possibility to perform experimental research in a setting comparable to an intensive care unit are preserved.

Background The second edition of the German-Austrian S3 guideline contains updated evidence-based recommendations for the treatment of patients with infarction-related cardiogenic shock (ICS), whose mortality is several times higher than that of patients with a hemodynamically stable myocardial infarction (1). Methods In five consensus conferences, the experts developed 95 recommendations-including two statements-and seven algorithms with concrete instructions. Results Recanalization of the coronary vessel whose occlusion led to the infarction is crucial for the survival of patients with ICS. The recommended method of choice is primary percutaneous coronary intervention (pPCI) with the implantation of a drug-eluting stent (DES). If multiple coronary vessels are diseased, only the infarct artery (the "culprit lesion") should be stented at first. For cardiovascular pharmacotherapy-primarily with dobutamine and norepinephrine-the recommended hemodynamic target range for mean arterial blood pressure is 65-75 mmHg, with a cardiac index (CI) above 2.2 L/min/m2. For optimal treatment in intensive care, recommendations are given regarding the type of ventilation (invasive rather than non-invasive, lungprotective), nutrition (no nutritional intake in uncontrolled shock, no glutamine supplementation), thromboembolism prophylaxis (intravenous heparin rather than subcutaneous prophylaxis), und further topics. In case of pump failure, an intra-aortic balloon pump is not recommended; temporary mechanical support systems (Impella pumps, veno-arterial extracorporeal membrane oxygenation [VA-ECMO], and others) are hemodynamically more effective, but have not yet been convincingly shown to improve survival. Conclusion Combined cardiological and intensive-care treatment is crucial for the survival of patients with ICS. Coronary treatment for ICS seems to have little potential for further improvement, while intensive-care methods can still be optimized.

Despite advances in the treatment of acute myocardial infarction with subsequent mortality reduction, which are mainly caused by the early timing of revascularization, cardiogenic shock still remains the leading cause of death with mortality rates still approaching 40 to 50%. Cardiogenic shock is characterized by a multiorgan dysfunction syndrome, often complicated by a systemic inflammatory response syndrome that affects the outcome more than the reduction of the cardiac contractile function. However, both European and American guidelines on myocardial infarction focus on interventional or surgical aspects only. Therefore, experts from eight German and Austrian specialty societies including the German Society for Thoracic and Cardiovascular Surgery published the German–Austrian S3 guideline “cardiogenic shock due to myocardial infarction: diagnosis, monitoring, and treatment” to provide evidence-based recommendations for the diagnosis and treatment of infarction-related cardiogenic shock in 2010 covering the topics of early revascularization, revascularization techniques, intensive care unit treatment including ventilation, transfusion regimens, adjunctive medical therapy, and mechanical support devices. Within the last 3 years, this guideline was updated as some major recommendations were outdated, or new evidence had been found. This review will therefore outline the management of patients with cardiogenic shock complicating acute myocardial infarction according to the updated guideline with a major focus on evidence-based recommendations which have been found relevant for cardiac surgery.

The second edition of the German-Austrian S3 guideline contains updated evidence-based recommendations for the treatment of patients with infarction-related cardiogenic shock (ICS), whose mortality is several times higher than that of patients with a hemodynamically stable myocardial infarction (1).In five consensus conferences, the experts developed 95 recommendations-including two statements-and seven algorithms with concrete instructions.Recanalization of the coronary vessel whose occlusion led to the infarction is crucial for the survival of patients with ICS. The recommended method of choice is primary percutaneous coronary intervention (pPCI) with the implantation of a drug-eluting stent (DES). If multiple coronary vessels are diseased, only the infarct artery (the "culprit lesion") should be stented at first. For cardiovascular pharmacotherapy-primarily with dobutamine and norepinephrine-the recommended hemodynamic target range for mean arterial blood pressure is 65-75 mmHg, with a cardiac index (CI) above 2.2 L/min/m2. For optimal treatment in intensive care, recommendations are given regarding the type of ventilation (invasive rather than non-invasive, lungprotective), nutrition (no nutritional intake in uncontrolled shock, no glutamine supplementation), thromboembolism prophylaxis (intravenous heparin rather than subcutaneous prophylaxis), und further topics. In case of pump failure, an intra-aortic balloon pump is not recommended; temporary mechanical support systems (Impella pumps, veno-arterial extracorporeal membrane oxygenation [VA-ECMO], and others) are hemodynamically more effective, but have not yet been convincingly shown to improve survival.Combined cardiological and intensive-care treatment is crucial for the survival of patients with ICS. Coronary treatment for ICS seems to have little potential for further improvement, while intensive-care methods can still be optimized.

Purpose Admixture of nitric oxide (NO) to the gas inspired with mechanical ventilation can be achieved through continuous, timed, or pulsed injection of NO into the inspiratory limb. The dose and timing of NO injection govern the inspired and intrapulmonary effect site concentrations achieved with different administration modes. Here we test the effectiveness and target reliability of a new mode injecting pulsed NO boluses exclusively during early inspiration. Methods An in vitro lung model was operated under various ventilator settings. Admixture of NO through injection into the inspiratory limb was timed either (i) selectively during early inspiration (“pulsed delivery”), or as customary, (ii) during inspiratory time or (iii) the entire respiratory cycle. Set NO target concentrations of 5–40 parts per million (ppm) were tested for agreement with the yield NO concentrations measured at various sites in the inspiratory limb, to assess the effectiveness of these NO administration modes. Results Pulsed delivery produced inspiratory NO concentrations comparable with those of customary modes of NO administration. At low (450 ml) and ultra-low (230 ml) tidal volumes, pulsed delivery yielded better agreement of the set target (up to 40 ppm) and inspiratory NO concentrations as compared to customary modes. Pulsed delivery with NO injection close to the artificial lung yielded higher intrapulmonary NO concentrations than with NO injection close to the ventilator. The maximum inspiratory NO concentration observed in the trachea (68 ± 30 ppm) occurred with pulsed delivery at a set target of 40 ppm. Conclusion Pulsed early inspiratory phase NO injection is as effective as continuous or non-selective admixture of NO to inspired gas and may confer improved target reliability, especially at low, lung protective tidal volumes.

Key points Carbonic anhydrase (CA) inhibitors such as acetazolamide inhibit hypoxic pulmonary vasoconstriction (HPV) in humans and other mammals, but the mechanism of this action remains unknown. It has been postulated that carbonic anhydrase may act as a nitrous anhydrase in vivo to generate nitric oxide (NO) from nitrite and that this formation is increased in the presence of acetazolamide. Acetazolamide reduces HPV in pigs without evidence of any NO generation, whereas nebulized sodium nitrite reduces HPV by NO formation; however; combined infusion of acetazolamide with sodium nitrite inhalation did not further increase exhaled NO concentration over inhaled nitrite alone in pigs exposed to alveolar hypoxia. We conclude that acetazolamide does not function as either a nitrous anhydrase or a nitrite reductase in the lungs of pigs, and probably other mammals, to explain its vasodilating actions in the pulmonary or systemic circulations. Abstract The carbonic anhydrase (CA) inhibitors acetazolamide and its structurally similar analogue methazolamide prevent or reduce hypoxic pulmonary vasoconstriction (HPV) in dogs and humans in vivo, by a mechanism unrelated to CA inhibition. In rodent blood and isolated blood vessels, it has been reported that inhibition of CA leads to increased generation of nitric oxide (NO) from nitrite and vascular relaxation in vitro. We tested the physiological relevance of augmented NO generation by CA from nitrite with acetazolamide in anaesthetized pigs during alveolar hypoxia in vivo. We found that acetazolamide prevents HPV in anaesthetized pigs, as in other mammalian species. A single nebulization of sodium nitrite reduces HPV, but this action wanes in the succeeding 3 h of hypoxia as nitrite is metabolized and excreted. Pulmonary artery pressure reduction and NO formation as measured by exhaled gas concentration from inhaled sodium nitrite were not increased by acetazolamide during alveolar hypoxia. Thus, our data argue against a physiological role of carbonic anhydrase as a nitrous anhydrase or nitrite reductase as a mechanism for its inhibition of HPV in the lung and blood in vivo.