Recommendations for treatment of critically ill patients with COVID-19 : Version 3 S1 guideline.

Since December 2019 a novel coronavirus (severe acute respiratory syndrome coronavirus 2, SARS-CoV-2) has rapidly spread around the world resulting in an acute respiratory illness pandemic. The immense challenges for clinicians and hospitals as well as the strain on many healthcare systems has been unprecedented.The majority of patients present with mild symptoms of coronavirus disease 2019 (COVID-19); however, 5-8% become critically ill and require intensive care treatment. Acute hypoxemic respiratory failure with severe dyspnea and an increased respiratory rate (>30/min) usually leads to intensive care unit (ICU) admission. At this point bilateral pulmonary infiltrates are typically seen. Patients often develop a severe acute respiratory distress syndrome (ARDS).So far, remdesivir and dexamethasone have shown clinical effectiveness in severe COVID-19 in hospitalized patients. The main goal of supportive treatment is to ascertain adequate oxygenation. Invasive mechanical ventilation and repeated prone positioning are key elements in treating severely hypoxemic COVID-19 patients.Strict adherence to basic infection control measures (including hand hygiene) and correct use of personal protection equipment (PPE) are essential in the care of patients. Procedures that lead to formation of aerosols should be carried out with utmost precaution and preparation.

[S2k Guideline - Recommendations for Inpatient Therapy of Patients with COVID-19]. / S2k-Leitlinie ­ Empfehlungen zur stationären Therapie von Patienten mit COVID-19.

Since December 2019, the novel coronavirus SARS-CoV-2 (Severe Acute Respiratory Syndrome - Corona Virus-2) has been spreading rapidly in the sense of a global pandemic. This poses significant challenges for clinicians and hospitals and is placing unprecedented strain on the healthcare systems of many countries. The majority of patients with Coronavirus Disease 2019 (COVID-19) present with only mild symptoms such as cough and fever. However, about 6 % require hospitalization. Early clarification of whether inpatient and, if necessary, intensive care treatment is medically appropriate and desired by the patient is of particular importance in the pandemic. Acute hypoxemic respiratory insufficiency with dyspnea and high respiratory rate (> 30/min) usually leads to admission to the intensive care unit. Often, bilateral pulmonary infiltrates/consolidations or even pulmonary emboli are already found on imaging. As the disease progresses, some of these patients develop acute respiratory distress syndrome (ARDS). Mortality reduction of available drug therapy in severe COVID-19 disease has only been demonstrated for dexamethasone in randomized controlled trials. The main goal of supportive therapy is to ensure adequate oxygenation. In this regard, invasive ventilation and repeated prone positioning are important elements in the treatment of severely hypoxemic COVID-19 patients. Strict adherence to basic hygiene, including hand hygiene, and the correct wearing of adequate personal protective equipment are essential when handling patients. Medically necessary actions on patients that could result in aerosol formation should be performed with extreme care and preparation.

Lower versus higher hemoglobin threshold for transfusion in ARDS patients with and without ECMO.

BACKGROUND: Efficacy and safety of different hemoglobin thresholds for transfusion of red blood cells (RBCs) in adults with an acute respiratory distress syndrome (ARDS) are unknown. We therefore assessed the effect of two transfusion thresholds on short-term outcome in patients with ARDS. METHODS: Patients who received transfusions of RBCs were identified from a cohort of 1044 ARDS patients. After propensity score matching, patients transfused at a hemoglobin concentration of 8 g/dl or less (lower-threshold) were compared to patients transfused at a hemoglobin concentration of 10 g/dl or less (higher-threshold). The primary endpoint was 28-day mortality. Secondary endpoints included ECMO-free, ventilator-free, sedation-free, and organ dysfunction-free composites. MEASUREMENTS AND MAIN RESULTS: One hundred ninety-two patients were eligible for analysis of the matched cohort. Patients in the lower-threshold group had similar baseline characteristics and hemoglobin levels at ARDS onset but received fewer RBC units and had lower hemoglobin levels compared with the higher-threshold group during the course on the ICU (9.1 [IQR, 8.7-9.7] vs. 10.4 [10-11] g/dl, P < 0.001). There was no difference in 28-day mortality between the lower-threshold group compared with the higher-threshold group (hazard ratio, 0.94 [95%-CI, 0.59-1.48], P = 0.78). Within 28 days, 36.5% (95%-CI, 27.0-46.9) of the patients in the lower-threshold group compared with 39.5% (29.9-50.1) of the patients in the higher-threshold group had died. While there were no differences in ECMO-free, sedation-free, and organ dysfunction-free composites, the chance for successful weaning from mechanical ventilation within 28 days after ARDS onset was lower in the lower-threshold group (subdistribution hazard ratio, 0.36 [95%-CI, 0.15-0.86], P = 0.02). CONCLUSIONS: Transfusion at a hemoglobin concentration of 8 g/dl, as compared with a hemoglobin concentration of 10 g/dl, was not associated with an increase in 28-day mortality in adults with ARDS. However, a transfusion at a hemoglobin concentration of 8 g/dl was associated with a lower chance for successful weaning from the ventilator during the first 28 days after ARDS onset. TRIAL REGISTRATION: ClinicalTrials.gov NCT03871166.

[Responsibilities of Weaning Centers during the COVID-19 Pandemic Outbreak - Recommendations for the Assignment of ICU Capacities in COVID-19 Patients as shown by the Berlin-Brandenburg POST-SAVE-Model]. / Aufgaben der Weaning-Zentren im Pandemiefall COVID-19.

The enormous increase in patients with severe respiratory distress due to the COVID-19 pandemic outbreak requires a systematic approach to optimize ventilated patient at risk flow. A standardised algorithm called "SAVE" was developed to distribute patients with COVID-19 respiratory distress syndrome requiring invasive ventilation. This program is established by now in Berlin. An instrumental bottleneck of this approach is the vacant slot assignment in the intensive care unit to guarantee constant patient flow. The transfer of the patients after acute care treatment is needed urgently to facilitate the weaning process. In a next step we developed a triage algorithm to identify patients at SAVE intensive care units with potential to wean and transfer to weaning institutions - we called POST SAVE. This manuscript highlights the algorithms including the use of a standardised digital evaluation tool, the use of trained navigators to facilitate the communication between SAVE intensive care units and weaning institutions and the establishment of a prospective data registry for patient assignment and reevaluation of the weaning potential in the future.

[Health services research in intensive care medicine in Germany : Status quo and future challenges exemplified by acute pulmonary failure]. / Versorgungsforschung in der Intensivmedizin in Deutschland : Status quo und zukünftige Herausforderungen am Beispiel des akuten Lungenversagens.

Health services research (HSR) is a multidisciplinary field of research that describes disease treatment and health care and their framework conditions. In the last 20 years, the HSR aspect became more and more the clinical focus of intensive care medicine. Under this aspect HSR investigates the use of clinical measures and their impact on patient outcome under routine intensive care medical conditions. This article provides an overview of the current state of HSR in intensive care medicine in Germany using the example of acute respiratory distress syndrome (ARDS). The ARDS still represents a clinical disease with high intra-hospital mortality (30-60%) despite progress in intensive care medicine. Survivors of ARDS have substantial long-term limitations on physical and mental health. The treatment of ARDS patients is tedious, laborious for intensive care unit staff and complex. Despite evident treatment recommendations, these are only insufficiently implemented in the clinical routine. With the help of quality indicators, benchmarking, certification and peer review procedures, the quality of intensive care treatment in the clinical routine can be documented and improved. An important role in HSR is patient safety and focusing on the outcome with evaluation of the patient's will. As part of the establishment of the innovation fund for HSR, promising intensive medical care projects have been promoted to improve the quality of care and the quality of long-term outcome for intensive care patients. An important focus lies on the identification of factors that improve long-term quality of life after intensive care. The expansion of registries and telemedicine in intensive care offers the opportunity to bundle and share experiences more effectively and thereby establish (guideline-based) treatment recommendations faster in the clinical practice.

[Prolonged Weaning - S2k-Guideline Published by the German Respiratory Society]. / Prolongiertes Weaning.

Mechanical ventilation (MV) is an essential part of modern intensive care medicine. MV is performed in patients with severe respiratory failure caused by insufficiency of respiratory muscles and/or lung parenchymal disease when/after other treatments, (i. e. medication, oxygen, secretion management, continuous positive airway pressure or nasal highflow) have failed.MV is required to maintain gas exchange and to buy time for curative therapy of the underlying cause of respiratory failure. In the majority of patients weaning from MV is routine and causes no special problems. However, about 20 % of patients need ongoing MV despite resolution of the conditions which precipitated the need for MV. Approximately 40 - 50 % of time spent on MV is required to liberate the patient from the ventilator, a process called "weaning."There are numberous factors besides the acute respiratory failure that have an impact on duration and success rate of the weaning process such as age, comorbidities and conditions and complications acquired in the ICU. According to an international consensus conference "prolonged weaning" is defined as weaning process of patients who have failed at least three weaning attempts or require more than 7 days of weaning after the first spontaneous breathing trial (SBT). Prolonged weaning is a challenge, therefore, an inter- and multi-disciplinary approach is essential for a weaning success.In specialised weaning centers about 50 % of patients with initial weaning failure can be liberated from MV after prolonged weaning. However, heterogeneity of patients with prolonged weaning precludes direct comparisons of individual centers. Patients with persistant weaning failure either die during the weaning process or are discharged home or to a long term care facility with ongoing MV.Urged by the growing importance of prolonged weaning, this Sk2-guideline was first published in 2014 on the initiative of the German Respiratory Society (DGP) together with other scientific societies involved in prolonged weaning. Current research and study results, registry data and experience in daily practice made the revision of this guideline necessary.The following topics are dealt with in the guideline: Definitions, epidemiology, weaning categories, the underlying pathophysiology, prevention of prolonged weaning, treatment strategies in prolonged weaning, the weaning unit, discharge from hospital on MV and recommendations for end of life decisions.Special emphasis in the revision of the guideline was laid on the following topics:- A new classification of subgroups of patients in prolonged weaning- Important aspects of pneumological rehabilitation and neurorehabilitation in prolonged weaning- Infrastructure and process organization in the care of patients in prolonged weaning in the sense of a continuous treatment concept- Therapeutic goal change and communication with relativesAspects of pediatric weaning are given separately within the individual chapters.The main aim of the revised guideline is to summarize current evidence and also expert based- knowledge on the topic of "prolonged weaning" and, based on the evidence and the experience of experts, make recommendations with regard to "prolonged weaning" not only in the field of acute medicine but also for chronic critical care.Important addressees of this guideline are Intensivists, Pneumologists, Anesthesiologists, Internists, Cardiologists, Surgeons, Neurologists, Pediatricians, Geriatricians, Palliative care clinicians, Rehabilitation physicians, Nurses in intensive and chronic care, Physiotherapists, Respiratory therapists, Speech therapists, Medical service of health insurance and associated ventilator manufacturers.

S2e guideline: positioning and early mobilisation in prophylaxis or therapy of pulmonary disorders : Revision 2015: S2e guideline of the German Society of Anaesthesiology and Intensive Care Medicine (DGAI).

The German Society of Anesthesiology and Intensive Care Medicine (DGAI) commissioneda revision of the S2 guidelines on "positioning therapy for prophylaxis or therapy of pulmonary function disorders" from 2008. Because of the increasing clinical and scientificrelevance the guidelines were extended to include the issue of "early mobilization"and the following main topics are therefore included: use of positioning therapy and earlymobilization for prophylaxis and therapy of pulmonary function disorders, undesired effects and complications of positioning therapy and early mobilization as well as practical aspects of the use of positioning therapy and early mobilization. These guidelines are the result of a systematic literature search and the subsequent critical evaluation of the evidence with scientific methods. The methodological approach for the process of development of the guidelines followed the requirements of evidence-based medicine, as defined as the standard by the Association of the Scientific Medical Societies in Germany. Recently published articles after 2005 were examined with respect to positioning therapy and the recently accepted aspect of early mobilization incorporates all literature published up to June 2014.

[Short version S2e guidelines: "Positioning therapy and early mobilization for prophylaxis or therapy of pulmonary function disorders"]. / Kurzversion S2e-Leitlinie - "Lagerungstherapie und Frühmobilisation zur Prophylaxe oder Therapie von pulmonalen Funktionsstörungen".

The German Society of Anesthesiology and Intensive Care Medicine (DGAI) commissioned a revision of the S2 guidelines on "positioning therapy for prophylaxis or therapy of pulmonary function disorders" from 2008. Because of the increasing clinical and scientific relevance the guidelines were extended to include the issue of "early mobilization" and the following main topics are therefore included: use of positioning therapy and early mobilization for prophylaxis and therapy of pulmonary function disorders, undesired effects and complications of positioning therapy and early mobilization as well as practical aspects of the use of positioning therapy and early mobilization. These guidelines are the result of a systematic literature search and the subsequent critical evaluation of the evidence with scientific methods. The methodological approach for the process of development of the guidelines followed the requirements of evidence-based medicine, as defined as the standard by the Association of the Scientific Medical Societies in Germany. Recently published articles after 2005 were examined with respect to positioning therapy and the recently accepted aspect of early mobilization incorporates all literature published up to June 2014.

S2k-Guideline "Prolonged Weaning".

All mechanically ventilated patients must be weaned from the ventilator at some stage. According to an International Consensus Conference the criteria for "prolonged weaning" are fulfilled if patients fail at least 3 weaning attempts (i. e. spontaneous breathing trial, SBT) or require more than 7 days of weaning after the first SBT. This occurs in about 15 - 20 % of patients.Because of the growing number of patients requiring prolonged weaning a German guideline on prolonged weaning has been developed. It is an initiative of the German Respiratory Society (Deutsche Gesellschaft für Pneumologie und Beatmungsmedizin e. V., DGP) in cooperation with other societies (see acknowledgement) engaged in the field chaired by the Association of Scientific and Medical Societies in Germany (Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften, AWMF).This guideline deals with the definition, epidemiology, weaning categories, underlying pathophysiology, therapeutic strategies, the weaning unit, transition to out-of-hospital ventilation and therapeutic recommendations for end of life care. This short version summarises recommendations on prolonged weaning from the German guideline.

[Prolonged weaning: S2k-guideline published by the German Respiratory Society]. / Prolongiertes Weaning: S2k-Leitlinie herausgegeben von der Deutschen Gesellschaftfür Pneumologie und Beatmungsmedizin e.V.

Mechanical ventilation (MV) is an essential part of modern intensive care medicine. MV is performed in patients with severe respiratory failure caused by insufficiency of the respiratory muscles and/or lung parenchymal disease when/after other treatments, i. e. oxygen, body position, secretion management, medication or non invasive ventilation have failed.In the majority of ICU patients weaning is routine and does not present any problems. Nevertheless 40-50 % of the time during mechanical ventilation is spent on weaning. About 20 % of patients need continued MV despite resolution of the conditions which originally precipitated the need for MV.There maybe a combination of reasons; chronic lung disease, comorbidities, age and conditions acquired in ICU (critical care neuromyopathy, psychological problems). According to an International Consensus Conference the criteria for "prolonged weaning" are fulfilled if patients fail at least three weaning attempts or require more than 7 days of weaning after the first spontaneous breathing trial. Prolonged weaning is a challenge. An inter- and multi-disciplinary approach is essential for weaning success. Complex, difficult to wean patients who fulfill the criteria for "prolonged weaning" can still be successfully weaned in specialised weaning units in about 50% of cases.In patients with unsuccessful weaning, invasive mechanical ventilation has to be arranged either at home or in a long term care facility.This S2-guideline was developed because of the growing number of patients requiring prolonged weaning. It is an initiative of the German Respiratory Society (Deutsche Gesellschaft für Pneumologie und Beatmungsmedizin e. V., DGP) in cooperation with other societies engaged in the field.The guideline is based on a systematic literature review of other guidelines, the Cochrane Library and PubMed.The consensus project was chaired by the Association of Scientific Medical Societies in Germany (Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften, AWMF) based on a formal interdisciplinary process applying the Delphi-concept. The guideline covers the following topics: Definitions, epidemiology, weaning categories, pathophysiology, the spectrum of treatment strategies, the weaning unit, discharge from hospital on MV and recommendations for end of life decisions. Special issues relating to paediatric patients were considered at the end of each chapter.The target audience for this guideline are intensivists, pneumologists, anesthesiologists, internists, cardiologists, surgeons, neurologists, pediatricians, geriatricians, palliative care clinicians, nurses, physiotherapists, respiratory therapists, ventilator manufacturers.The aim of the guideline is to disseminate current knowledge about prolonged weaning to all interested parties. Because there is a lack of clinical research data in this field the guideline is mainly based on expert opinion.

[Nationwide exposure model for COVID-19 intensive care unit admission]. / Bundesweites Belastungsmodell für Intensivstationen durch COVID-19.

BACKGROUND: Forecasting models for intensive care occupancy of coronavirus disease 2019 (COVID-19) patients are important in the current pandemic for strategic planning of patient allocation and avoidance of regional overcrowding. They are often trained entirely on retrospective infection and occupancy data, which can cause forecast uncertainty to grow exponentially with the forecast horizon. METHODOLOGY: We propose an alternative modeling approach in which the model is created largely independent of the occupancy data being simulated. The distribution of bed occupancies for patient cohorts is calculated directly from occupancy data from "sentinel clinics". By coupling with infection scenarios, the prediction error is constrained by the error of the infection dynamics scenarios. The model allows systematic simulation of arbitrary infection scenarios, calculation of bed occupancy corridors, and sensitivity analyses with respect to protective measures. RESULTS: The model was based on hospital data and by adjusting only two parameters of data in the Aachen city region and Germany as a whole. Using the example of the simulation of the respective bed occupancy rates for Germany as a whole, the loading model for the calculation of occupancy corridors is demonstrated. The occupancy corridors form barriers for bed occupancy in the event that infection rates do not exceed specific thresholds. In addition, lockdown scenarios are simulated based on retrospective events. DISCUSSION: Our model demonstrates that a significant reduction in forecast uncertainty in occupancy forecasts is possible by selectively combining data from different sources. It allows arbitrary combination with infection dynamics models and scenarios, and thus can be used both for load forecasting and for sensitivity analyses for expected novel spreading and lockdown scenarios.

[Indications and limitations of ECMO therapy : Considerations on evidence, treatment decisions and ethical challenges]. / Indikationen und Grenzen der ECMO-Therapie : Überlegungen zur Evidenz, Therapieentscheidung und ethischen Herausforderung.

The present work sheds light on the possibilities and limitations of modern extracorporeal membrane oxygenation (ECMO) therapy in the case of heart or lung failure. Since the number of applications of extracorporeal lung and heart/lung replacement procedures has increased dramatically in the last few years in severely ill patients, decision-making for a meaningful indication and in the course of a possible therapy target change has become particularly difficult, especially with regard to the complex situation in organ transplantation in Germany. An attempt is made to elucidate the dilemma between data from large controlled trials and epidemiological studies and the patients' individuality.

Bronchial fistulae in ARDS patients: management with an extracorporeal lung assist device.

Patients with bronchial tree lesions feature, in particular, a high risk for developing bronchial fistulae after surgical repair when the clinical situation is complicated by acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) and mechanical ventilation is needed. The current authors hypothesised that extracorporeal carbon dioxide removal would significantly decrease inspiratory airway pressures, thus promoting the protection of surgical bronchial reconstruction. Four patients were studied after surgical reconstruction of bronchial fistulae in whom ALI/ARDS developed and mechanical ventilation with positive end-expiratory pressure was required. Gas exchange, tidal volumes, airway pressures, respiratory frequency, vasopressor and sedation requirements were analysed before and after initiation of a pumpless extracorporeal lung assist device (pECLA; NovaLung, Talheim, Germany). Initiation of pECLA treatment enabled a reduction of inspiratory plateau airway pressures from 32.4 to 28.6 cmH(2)O (3.2 to 2.8 kPa), effectively treated hypercapnia (from 73.6 to 53.4 mmHg (9.8 to 7.1 kPa)) and abolished respiratory acidosis (from pH 7.24 to 7.41). All patients survived and were discharged to rehabilitation clinics. In patients after surgical bronchial reconstruction that was complicated by acute lung injury/acute respiratory distress syndrome, use of pumpless extracorporeal carbon dioxide removal was safe and efficient. Initiation of a pumpless extracorporeal lung assist device enabled a less invasive ventilator management, which may have contributed to healing of surgical bronchial repair.

Evidence-based therapy of severe acute respiratory distress syndrome: an algorithm-guided approach.

Despite considerable research and constantly emerging treatment modalities, the mortality associated with acute respiratory distress syndrome (ARDS) has remained virtually unchanged over the last decade. Clinical studies have been unable to show a reduction in mortality for most therapeutic interventions except for low tidal volume ventilation. Failure to prove a mortality benefit might be a result of the varying severity of ARDS in the patients studied. Nevertheless, positive responses to single supportive measures (inhaled nitric oxide, prone positioning and extracorporeal membrane oxygenation) have been demonstrated in multiple trials. Criteria for administration, weaning and discontinuation of these supportive interventions have never been described in detail. In this context, implementation of an evidence-based algorithm might facilitate clinical management of severe ARDS. This review summarizes the current evidence base and proposes a new treatment algorithm that aims to prioritize the administration of advanced strategies in a multimodal approach for ARDS.

[Extracorporeal lung support procedures (ECMO/iLA)]. / Extrakorporale Lungenunterstützungsverfahren (ECMO/iLA).

The management of acute lung injury in adults requires specific therapeutic measures including techniques of extracorporeal lung support. In patients suffering from severe acute respiratory distress syndrome (ARDS) with life-threatening hypoxaemia, a pump-driven, veno-venous extracorporeal membrane oxygenation (ECMO) has been established. Recently, a pumpless extracorporeal lung support system was developed using an arterio-venous bypass into which a gas exchange membrane is integrated ("interventional lung assist" [iLA]). ILA provides effective CO2 elimination and a moderate improvement in oxygenation. In both techniques, an improvement in survival has not been demonstrated in prospective investigations. ECMO and iLA might be associated with serious complications (bleeding, ischaemia), thus further randomised prospective studies are warranted to elucidate specific indications. In patients with severe asthma or exacerbation of chronic obstructive pulmonary disease, iLA might represent an attractive rescue therapy in the future.

Measuring Energy Expenditure in extracorporeal lung support Patients (MEEP) - Protocol, feasibility and pilot trial.

PURPOSE: Indirect calorimetry (IC) is the gold standard for measuring energy expenditure (EE). Due to O2 uptake and CO2 removal by both the extracorporeal lung support (ECLS) membrane and the lungs, a conventional IC is not feasible and no data available. Our MEEP (Measuring Energy Expenditure in ECLS Patients) protocol enables the determination of the REE in patients with ECLS, the comparison to patients without ECLS, and accuracy assessment of estimating equations. METHODS: In the MEEP protocol, a conventional IC is performed and extended by a calculation of the O2 uptake and the CO2 elimination by the ECLS membrane. Sum O2 uptake and CO2 elimination were used in the equation of Weir to calculate EE. We included 20 patients with ARDS on veno-venous (vv)-extracorporeal membrane oxygenation (ECMO) treatment, and 20 matched ARDS patients without ECLS as control. EE measurements were compared to the most prevalent predicting equations for EE. RESULTS: The new MEEP-protocol was shown to be feasible. None of the estimating equations matched the measured EE. Measured EE values did not significantly differ between the ARDS patients with vv-ECMO (2013 kcal/d [1786/2333]) and ARDS patients without ECLS (1857 kcal/d [1602/2085]) (p = 0.165). The blood flow through the vv-ECMO itself did not influence the EE. CONCLUSION: Using the MEEP protocol, EE becomes easily measurable in patients with ECLS. We recommend the implementation of sequential measurements of EE in the critically ill, especially for patients with ECLS, but also for those without, in order to improve goal directed nourishment.

Hyperactive delirium and blood glucose control in critically ill patients.

Delirium is a common complication of critically ill patients and is often associated with metabolic disorders. One of the most frequent metabolic disorders in intensive care unit (ICU) patients is hyperglycaemia. The aim of this retrospective study of 196 adult ICU patients was to determine if there is an association between hyperactive delirium and blood glucose levels in ICU patients. Hyperactive delirium was diagnosed using the delirium detection score. Blood glucose levels were monitored by blood gas analysis every 4 h. Hyperactive delirium was detected in 55 (28%) patients. Delirious patients showed significantly higher blood glucose levels than non-delirious patients Higher overall complication rates, length of ventilation, ICU stay and mortality rates were seen in the delirium group. In a multivariate analysis, glucose level, alcohol abuse, APACHE II score, complication by hospital-acquired pneumonia and a diagnosis of polytrauma on-admission all significantly influenced the appearance of delirium.

[Computed tomographic criteria as expected effect to inhaled nitric oxide in patients with severe acute respiratory distress syndrome]. / Computertomographische Kriterien für den zu erwartenden Effekt von inhaliertem Stickstoffmonoxid bei Patienten mit schwerem akutem Lungenversagen.

PURPOSE: Inhaled nitric oxide (iNO) is an effective therapy for severe hypoxemia in most patients with acute respiratory distress syndrome (ARDS). For unknown reason, a subset of ARDS patients does not respond favorably to iNO therapy. We hypothesized that radiological manifestation of lung injury may be related to iNO response. MATERIALS AND METHODS: We retrospectively analyzed data from n = 25 ARDS patients who received iNO, and underwent chest CT within 72 h prior to inhaled treatment. The morphology of coherently pathologic lung tissue was characterized by the length of the borderline between consolidated, infiltrated and atelectatic lung tissue and radiologically normal lung tissue. This quantity was expressed as relative fraction of the visceral pleural circumference and averaged over all CT slices. Furthermore we semiquantitatively determined the total volume of consolidated lung tissue as part of the whole lung. RESULTS: In n = 6 non-responders to iNO (DeltaPaO2 < 10 %), we determined a short relative borderline between normal and consolidated lung tissue due to the presence of large and coherently consolidated lung regions. In n = 19 iNO responders (DeltaPaO2 > 10 %), we found significantly less coherently consolidated lung tissue evidenced by an increased relative borderline when compared to iNO non-responders (0.09 +/- 0.02 vs. 0.1 +/- 0.01; P < 0.05). Moreover, there was a moderate and significant correlation between DeltaPaO2 induced by iNO and the relative borderline in all patients studied (R = 0.59; P < 0.05). Total fraction of consolidated lung tissue volume was not different between iNO non-responders and responders (60 +/- 3 % vs. 54 +/- 2 % n. s.). CONCLUSION: Our data demonstrate that the gross morphological distribution of pathological lung tissue influences iNO response in ARDS. Inhaled NO was most beneficial in injured lungs characterized by many small consolidated areas surrounded by normal lung tissue. The increased borderline between pathologic and normal lung tissue offers additional possibility for iNO to divert blood flow from shunt areas to ventilated lung regions, which consequently improves arterial oxygenation.