[ARDS - An Update - Part 2: Therapy and Outcome]. / ARDS ­ Ein Update ­ Teil 2: Therapie und Outcome.

The Acute Respiratory Distress Syndrome (ARDS) is defined by hypoxemic respiratory failure due to inflammatory response within the lung usually requiring invasive mechanical ventilation. Despite more than 50 years of scientific research numerous issues especially regarding mechanical ventilation as the most important treatment option remain unclear. Most important, adjustment of mechanical ventilation is challenging due to desirable beneficial effects on pulmonary gas exchange on the one hand and deleterious effects in terms of ventilator-associated lung injury on the other. Specifically, optimal settings of positive end-expiratory pressure and the role of spontaneous breathing activity are still controversial. Because no specific pharmacological therapy revealed beneficial effects until today, adjunctive treatment is actually limited to prone positioning and restrictive fluid balance. Long-term outcome of ARDS survivors is often affected by anxiety and mental health disorders.

[ARDS - An Update - Part 1: Epidemiology, Pathophysiology and Diagnosis]. / ARDS ­ Ein Update ­ Teil 1: Epidemiologie, Pathophysiologie und Diagnostik.

The Acute Respiratory Distress Syndrome (ARDS) is defined by hypoxemic respiratory failure caused by inflammatory response within the lung usually requiring invasive mechanical ventilation. Despite more than 50 years of research numerous issues regarding epidemiology, pathophysiology and diagnosis remain unclear until today: Due to rather unspecific clinical diagnostic criteria incidence of ARDS varies considerably in clinical trials with a range from 4 to 79 cases per 100 000 persons per year. Consequently, mortality is also highly variable from about 40 to 60% in severe ARDS. Pathophysiology is mainly characterized by granulocyte infiltration of the lung thereby inducing interstitial and intra-alveolar lung edema with surfactant depletion and atelectasis formation. However, it is unknown whether pulmonary and extrapulmonary causes and risk factors for ARDS are accompanied by different pathophysiologic processes due to primary endothelial and epithelial injury. Thus, possible benefits of corresponding biomarker panels for the differentiation of endothelial and epithelial lung injury are also speculative until today. Therefore, ARDS diagnosis is still based on clinical findings and radiological imaging.

Extracorporeal membrane oxygenation.

PURPOSE OF REVIEW: Extracorporeal membrane oxygenation (ECMO) has become a more or less accepted standard in the algorithm of advanced acute respiratory distress syndrome therapy in adult patients when all other treatment options have failed. This article reviews the current status of ECMO therapy with particular focus on new technical developments and their potential implications for performance and indications for ECMO therapy. RECENT FINDINGS: A recently published review on a single-center experience in 255 adult ECMO patients identified using multivariate logistic regression analysis age, sex, initial pH 7.10 or lower and PaO2/FiO2 ratio, and days of mechanical ventilation before ECMO as a significant predictors of survival. Additionally, a careful cost-effectiveness study for neonatal ECMO relating a 4-year base to the UK neonatal ECMO trial has clearly demonstrated cost-effectiveness. SUMMARY: Over the years, the technique for ECMO therapy underwent substantial changes in indications and the materials used. Impressive technical progress has been made in pumps, oxygenators, and coating of artificial surfaces, leading to a higher biocompatibility and to a lower rate of procedure-related complications. The potential of new inline pumps in combination with a decreasing rate of procedure-related complications might lead to a re-evaluation of the role of extracorporeal lung support in acute respiratory distress syndrome therapy. A very recent development is the use of spontaneous arteriovenous devices for carbon dioxide removal, allowing significant reduction of ventilator settings at decreased carbon dioxide partial pressures and at increased pH values. Ongoing studies are looking at the potential of this approach to reduce side effects of mechanical ventilation further.

Comparison of continuous cardiac output measurements in patients after cardiac surgery.

OBJECTIVE: To investigate in a direct comparison accuracy and precision of continuous cardiac output measurements assessed by continuous pulmonary artery thermodilution technique (TDCCO), continuous pulse contour analysis (PCCO), and noninvasive partial CO(2)-rebreathing technique (NICO) in patients after coronary artery bypass grafting (CABG) during the postoperative period. DESIGN: Prospective, controlled clinical study. SETTING: University hospital. PARTICIPANTS: Twenty-two patients undergoing elective CABG surgery. INTERVENTIONS: Hemodynamic measurements were performed after admission to the ICU and in sequence every 2 hours during the subsequent 6-hour period. Simultaneously, cardiac output (CO) was measured using a TDCCO, PCCO, and NICO. After the continuous cardiac output measurements were read, bolus thermodilution-derived cardiac output was obtained from thermodilution curves detected in the pulmonary artery (TDBCO(pa)). Four intermittent consecutive boli consisting of 10 mL of ice-cold saline were randomly injected over the ventilatory cycle. MEASUREMENTS AND MAIN RESULTS: The comparison between the continuous cardiac output measurement methods TDCCO versus PCCO showed a bias of -0.12 L/min, between TDCCO versus NICO -0.17 L/min, and between PCCO versus NICO -0.44 L/min. The comparison to the reference technique between TDBCO(pa) versus TDCCO revealed a bias of -0.28 L/min, between TDBCO(pa) versus PCCO -0.40 L/min, and between TDBCO(pa) versus NICO -0.64 L/min. CONCLUSIONS: The results of this clinical investigation show agreement between TDCCO and PCCO to satisfy clinical requirements in a setting of postoperative patients after cardiac surgery. In contrast, the NICO monitor is of very limited use in these patients.

Methylene blue administration in severe systemic inflammatory response syndrome (SIRS) after thoracic surgery.

A 66-year-old male patient developed significant pleural effusion on the right side six years after coronary bypass grafting and mitral valve replacement. After pleurocentesis, hemo-pneumothorax developed and finally resulted in complete atelectasis of the right lung. Three weeks later, the patient was transferred to our department, and underwent a right lateral thoracotomy. The hematoma was removed and a complete decortication was performed. Four hours postoperatively the patient developed severe SIRS with beginning multiorgan failure. Even extremely high doses of norepinephrine could not raise the systemic vascular resistance. Single intravenous administration of methylene blue lead to significant and permanent improvement of the hemodynamic status.