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Patients discovered recumbent, helpless and incapacitated, awake or unresponsive are referred to as "long lie trauma" (LLT) in the German medical jargon. Yet, a characterization of this cohort is missing.We retrospectively analyzed all LLT patients admitted to the emergency department of the University Hospital Cologne from July 2018 to December 2020.A total of 50 LLT patients (median age 76 years, median time on the ground 13.5 h) were identified. The FD was most often attributed to primary cerebral causes in 40% of the cases (20% ischemic stroke, 16% intracranial hemorrhage, 4% epilepsy), intoxication/overdose (12%), and trauma (10%). It was often associated with infection (52%), injury (22%), hypovolemia (66%), acute kidney injury (20%), and severe rhabdomyolysis (creatine kinase ≥ 5000 U/l, 21%) as well as severe hypothermia 32 °C (20%). Overall, 69% of the patients were admitted to an intensive care unit and in-hospital mortality was 50%.The term "long lie trauma" describes a complex clinical situation, in which various conditions lead to an incapacitated state with acute onset, which then causes further adverse health effects. Trauma or tissue damage were no obligatory requirement in this syndrome. Considering the high morbidity and in-hospital mortality, patients should initially be treated in the emergency room by an interdisciplinary team.HINTERGRUND: Bisher fehlen Versorgungsdaten für Patienten mit Liegetrauma (LT).Deskriptive retrospektive Analyse aller rettungsdienstlich mit einem LT der Notaufnahme des Universitätsklinikums Köln von 07.2018 bis 12.2020 zugeführten Patienten.Insgesamt konnten 50 Patienten mit LT (Altersmedian 76 Jahre, Liegedauer im Median 13,5 h) im Untersuchungszeitraum identifiziert werden. Die zugrunde liegende Ursache für das LT war in 40 % primär neurologisch (ischämischer Schlaganfall: 20 %, intrakranielle Blutung: 16 %, Epilepsie: 4 %), in 12 % eine Intoxikation und in 10 % ein häusliches Trauma. Häufige assoziierte Diagnosen waren Infektionen (52 %), Traumafolgen (22 %), Exsikkose (66 %), akute Nierenfunktionsstörung (20 %), schwere Rhabdomyolyse (Kreatininkinase ≥ 5000 U/l, 21 %) und schwere Hypothermie 32 °C (20 %). Insgesamt wurden 69 % der Patienten auf einer Intensivstation aufgenommen und die Krankenhausletalität betrug 50 %.Das LT beschreibt einen Patientenzustand, bei dem infolge vielfältiger Ursachen plötzlich die eigenständige Mobilisierung und ein selbstständiges Hilfeholen verhindert werden und dadurch weitere Gesundheitsschäden entstehen. Bei diesem Syndrom sind Gewebsschäden als Folge des Liegens keine notwendige Voraussetzung für das Vorliegen eines LT. Aufgrund der hohen Morbidität und Letalität sollten diese Patienten in einem nichttraumatologischen Schockraum aufgenommen werden.

Objectives To test if the early kinetics of neurofilament light (NFL) in blood adds to the absolute values of NFL in the prediction of outcome, and to evaluate if NFL can discriminate individuals with severe hypoxic–ischemic brain injury (sHIBI) from those with other causes of poor outcome after out-of-hospital cardiac arrest (OHCA). Design and setting Monocentric retrospective study involving individuals following non-traumatic OHCA between April 2014 and April 2016. NFL concentrations were determined on a SiMoA HD-1 device using NF-Light Advantage Kits. Participants Of 73 patients screened, 53 had serum samples available for NFL measurement at three timepoints (after 3, 24, and 48 h of admission). Of these 53 individuals, 43.4% had poor neurologic outcome at discharge as assessed by Glasgow–Pittsburgh cerebral performance categories, and, according to a current prognostication algorithm, poor outcome due to sHIBI in 20.7%. Main outcome measure Blood NFL and its early kinetics for prognostication of outcome and prediction of sHIBI after OHCA. Results An absolute NFL > 508.6 pg/ml 48 h after admission, or a change in NFL > 494 pg/ml compared with an early baseline value predicted outcome, and discriminated severe sHIBI from other causes of unfavorable outcome after OHCA with high sensitivity (100%, 95%CI 70.0–100%) and specificity (91.7%, 95%CI 62.5–100%). Conclusions Not only absolute values of NFL, but also early changes in NFL predict the outcome following OHCA, and may differentiate sHIBI from other causes of poor outcome after OHCA with high sensitivity and specificity. Our study adds to published data, overall corroborating that NFL measured in blood should be implemented in prognostication algorithms used in clinical routine.

In the situation of a shortage of ventilation beds, ethically justifiable, transparent and comprehensible decisions must be made. This concept proposes that all patients are first intubated depending on necessity and then assessed by a triage team afterwards. In this situation newly admitted COVID patients compete with newly admitted Non-COVID patients as well as patients already treated in intensive care units for a ventilator. The combination of short-term and long-term prognoses should enable the interprofessional triage team to make comprehensible decisions. The aim of the prioritization concept is to save as many human lives as possible and to relieve the treatment team of the difficult decision on prioritization.In der Situation des Beatmungsbettenmangels sind ethisch begründbare, transparente und nachvollziehbare Entscheidungen zu treffen. Dieses Konzept sieht vor, dass zunächst alle Patienten nach Notwendigkeit intubiert und dann von einem Triage-Team beurteilt werden. Dabei stehen neu aufgenommene COVID-Patienten mit neu aufgenommenen Nicht-COVID-Patienten und bereits intensivmedizinisch behandelte Patienten in Konkurrenz um ein Beatmungsgerät. Die Kombination der kurz- und langfristigen Prognose soll dem interprofessionellen Triage-Team ermöglichen, nachvollziehbare Entscheidungen zu treffen. Ziel des Priorisierungskonzeptes ist es, möglichst viele Menschenleben zu retten und die Behandlungsteams von der schwierigen Entscheidung der Priorisierung zu entlasten.

Extracorporeal cardiopulmonary resuscitation (eCPR) is a rapidly growing treatment strategy due to significant improvement in selected patients' survival rates. Gender-related differences might impact the outcome of therapeutic measures. Therefore, we sought to investigate patients with eCPR at our interdisciplinary extracorporeal membrane oxygenation center regarding sex-related differences with the view to potentially adjusting current selection criteria. From January 2016 to December 2019, 71 patients underwent eCPR at our institution. Data before eCPR and early outcome parameters were analyzed comparing male and female patients. The cohort analyzed consisted of 60 male (84%) and 11 female (15%) patients. Comparing both groups, male patients significantly more frequently suffered out-of-hospital cardiac arrest (68% male vs. 36% female, P = .04), whereas female patients were associated with more in-hospital cardiac arrest (32% male vs. 64% female, P = .04). Creatinine levels differed significantly (1.5 (1.1;2.1) mg/dL in male vs. 1.0 (0.7;1.5) mg/dL in female patients, P = .03). Also, several hepatic parameters showed a significant difference between the groups: aspartate aminotransferase 423 (249;804) U/L in male vs. 115 (61;408) U/L in female patients, P = .01; alanine aminotransferase 174 (102;446) U/L in male vs. 86 (36;118) U/L in female patients, P = .01). Renal failure requiring hemodialysis occurred more frequently in men than in women (P

LAA occlusion has become a favourable option in patients with atrial fibrillation not eligible for oral anticoagulation therapy. Proof of effectiveness of LAA closure devices in a midterm follow-up period. This retrospective single-center cohort study analysed outcome in patients treated with AMPLATZER Cardiac Plug or AMPLATZER Amulet device. A standardized follow-up by phone call focusing on data of death, stroke and bleeding events was performed. Routine antiplatelet strategy was DAPT for 3 months post procedural. 212 patients (mean age 77 ± 6 years) were included. Follow up was performed in 197 (93%) patients. Patients were at high risk for thromboembolic or bleeding events (prior stroke/TIA 29%; prior bleeding 54%. Overall, there was a mean follow-up period of 1244.2 days (± 756.7) and a total of 674 patient years. We observed 25 events later than day 8 post procedure. We were able to demonstrate a high effectiveness of the AMPLATZER Cardiac Plug/AMPLATZER Amulet devices regarding the prevention of stroke and bleedings in a high-risk real-world cohort during a midterm follow-up period. Overall, we observed remarkably lower rates of stroke and bleedings as predicted with CHA2DS2–VASc and HASBLED scores.

Objectives Central or peripheral venoarterial extracorporeal membrane oxygenation (va ECMO) is widely used in postcardiotomy cardiogenic shock (PCS). Available data suggest controversial results for both types. Our aim was to investigate PCS patients treated with either peripheral (pECMO) or central ECMO (cECMO) concerning their outcome. Methods Between April 2006 and October 2016, 156 consecutive patients with va ECMO therapy due to PCS were identified and included in this retrospective analysis. Patients were divided into cECMO and pECMO groups. Statistical analysis of risk factors concerning 30-day mortality of the mentioned patient cohort was performed using IBM SPSS Statistics. Results Fifty-six patients received cECMO and 100 patients were treated with pECMO due to PCS. In the group of cECMO peripheral vascular disease was significantly more present (cECMO 19 [34%] vs pECMO 14 [14%]; P < .01). On-site ECMO complications occurred significantly more frequent in patients treated with cECMO (cECMO 44 [79%] vs pECMO 54 [54%] g/dL; P < 0.01). More often cECMO patients required a second look operation due to mediastinal bleeding (cECMO 52 [93%] vs pECMO 61 [61%] g/dL; P < .01). Thirty-day mortality was comparable with nearly 70% in both cohorts (cECMO 39 [70%] vs pECMO 69 [69%]; P = .93). Conclusion Patients supported by cECMO or pECMO due to refractory PCS did not show significant differences in 30-day mortality, despite a lower incidence of on-site ECMO complications and re-exploration in pECMO patients. PCS itself is associated with high mortality and peripheral cannulation might help to save resources compared with central cannulation.

Aims This network meta-analysis aimed to assess the effect of early coronary angiography (CAG) compared with selective CAG (late and no CAG) for patients after out-of-hospital cardiac arrest without ST-elevation myocardial infarction (NSTE-OHCA). Methods and results A systematic literature search was performed using the EMBASE, MEDLINE and Web of Science databases without restrictions on publication date. The last search was performed on 15 July 2022. Randomized controlled trials (RCTs) and non-randomized studies (NRS) comparing the effect of early CAG to selective CAG after NSTE-OHCA on survival and/or neurological outcomes were included. Meta-analyses were performed based on a DerSimonian-Laird random effects model. A total of 18 studies were identified by the literature search. After the exclusion of two studies due to high risk of bias, 16 studies (six RCTs, ten NRS) were included in the final analyses. Meta-analyses showed a statistically significant increase in survival after early CAG compared with selective CAG in the overall analysis [OR: 1.40, 95% confidence interval (CI): (1.12–1.76), P < 0.01, I2 = 68%]. This effect was lost in the subgroup analysis of RCTs [OR: 0.89, 95% CI: (0.73–1.10), P = 0.29, I2 = 0%]. Random effects model network meta-analysis of NRS based on a Bayesian method showed statistically significant increased survival after late compared with early CAG [OR: 4.20, 95% CI: (1.22, 20.91)]. Conclusion The previously reported superiority of early CAG after NSTE-OHCA is based on NRS at high risk of selection and survivorship bias. The meta-analysis of RCTs does not support routinely performing early CAG after NSTE-OHCA.

The effect of respiratory infectious diseases on STEMI incidence, but also STEMI care is not well understood. The Influenza 2017/2018 epidemic and the COVID-19 pandemic were chosen as observational periods to investigate the effect of respiratory virus diseases on these outcomes in a metropolitan area with an established STEMI network. We analyzed data on incidence and care during the COVID-19 pandemic, Influenza 2017/2018 epidemic and corresponding seasonal control periods. Three comparisons were performed: (1) COVID-19 pandemic group versus pandemic control group, (2) COVID-19 pandemic group versus Influenza 2017/2018 epidemic group and (3) Influenza 2017/2018 epidemic group versus epidemic control group. We used Student’s t-test, Fisher’s exact test and Chi square test for statistical analysis. 1455 patients were eligible. The daily STEMI incidence was 1.49 during the COVID-19 pandemic, 1.40 for the pandemic season control period, 1.22 during the Influenza 2017/2018 epidemic and 1.28 during the epidemic season control group. Median symptom-to-contact time was 180 min during the COVID-19 pandemic. In the pandemic season control group it was 90 min (p = 0.183), and in the Influenza 2017/2018 cohort it was 90 min, too (p = 0.216). Interval in the epidemic control group was 79 min (p = 0.733). The COVID-19 group had a door-to-balloon time of 49 min, corresponding intervals were 39 min for the pandemic season group (p = 0.038), 37 min for the Influenza 2017/2018 group (p = 0.421), and 38 min for the epidemic season control group (p = 0.429). In-hospital mortality was 6.1% for the COVID-19 group, 5.9% for the Influenza 2017/2018 group (p = 1.0), 11% and 11.2% for the season control groups. The respiratory virus diseases neither resulted in an overall treatment delay, nor did they cause an increase in STEMI mortality or incidence. The registry analysis demonstrated a prolonged door-to-balloon time during the COVID-19 pandemic.

Objectives Right ventricular (RV) failure is associated with poor outcome and increased mortality in cardiac surgery. Aim of our study was to analyze the outcome of veno arterial extracorporeal membrane oxygenation (va ECMO) therapy in patients with isolated RV failure in postcardiotomy cardiogenic shock (PCS) and to evaluate risk factors associated with 30-day-mortality. Methods Between August 2006 until August 2016, 64 consecutive patients with va ECMO therapy due to fulminant RV failure in PCS were identified and included in this retrospective observation. Further, outcome data and a comparison of va ECMO survivors and nonsurvivors was conducted. Results The mean age of the patient cohort was 63 ± 14 years. Patients were treated with va ECMO for 79 ± 61 hours. Twenty-eight patients (44%) were successfully weaned off ECMO support. Overall 30-day-mortality was 88% (56/64). Hemoglobin concentration before ECMO implantation, maximum rise of muscle-brain type creatine kinase during ECMO therapy, as well as lactic acid concentration 24 hours after initiation of va ECMO therapy were predictive for 30-day mortality. Conclusion ECMO therapy in RV failure due to PCS is shown to be associated with an excessive mortality. Regarding our data, va ECMO might only be an appropriate short-term mechanical assist device separating patients form cardiopulmonary bypass with an acceptable weaning rate. Particularly, in case of failed hemodynamic recovery of the right heart on va ECMO, direct RV bypass systems might function as a bailout option. Additionally, cardiac enzymes and lactic acid might provide valuable information in meeting therapy-related decisions.

BackgroundSince December 2019 the novel coronavirus (SARS-CoV-2) is the center of global attention due to its rapid transmission and toll on health care systems and global economy. Population-based serosurveys measuring antibodies for SARS-CoV-2 provide one method for estimating infection rates and monitoring the progression of the epidemic.MethodsIn June 2020 we succeeded in testing almost half of the population of an Austrian township (n=835 of 1359 inhabitants) with a reported higher incidence for COVID-19 infections. We determined the level of prevalence for SARS-CoV-2 in this population, factors affecting, and symptoms correlated with prior infection.ResultsWe found a high prevalence of 9% positive antibodies among the town population in comparison to 6% of the neighboring villages. Only 20% of SARS-CoV-2 cases self-declared being asymptomatic. In contrast, we identified six single major symptoms, including anosmia/ageusia, weight loss, anorexia, general debility, dyspnea, and fever, and especially their combination to be of high prognostic value for predicting SARS-CoV-2 infection in a patient. Our comparison of the gold standard lab-based ELISA test and the on-site antibody test demonstrated a lack of accuracy for the latter test form.ConclusionsThis population study demonstrated a high prevalence of antibodies to SARS-CoV-2 as a marker of both active and past infections in an Austrian township. Several symptoms revealed a diagnostic value especially in combination. Results from self-administered antibody tests should be considered with caution.

Objectives: Extracorporeal cardiopulmonary resuscitation (eCPR) is a rapidly growing treatment strategy due to increasing survival rates in selected patients. Additional left ventricular mechanical unloading, using a transfemoral micro-axial blood pump (Impella®), might improve patients’ outcomes. In this regard, we sought to investigate patients who suffered OHCA (out- of hospital cardiac arrest) or IHCA (in-hospital cardiac arrest) with subsequent eCPR (extracorporeal cardiopulmonary resuscitation) via VA-ECMO (veno-arterial extracorporeal membrane oxygenation) and concomitant Impella® implantation. Methods: From January 2016 until December 2019, 71 patients underwent eCPR at our institution. Data prior eCPR and early outcome parameters were analyzed comparing patients who were supported with an additional transfemoral micro-axial blood pump (ECMO+Impella®, n= 7) and patients without additional (ECMO, n=64) support during VA-ECMO therapy. Results: Baseline data did not significantly differ between groups. All-cause mortality was significantly lower in the ECMO+Impella® group (83% vs. 29%, p= 0.01). The time of circulatory support was shorter in the ECMO+Impella® cohort (3.16±2.09 vs. 6.5±2.79, p=0.01). Additionally, ECMO weaning was significantly more feasible in patients with ECMO+Impella® (71% vs. 29%, p =0.02). Patients treated with additional Impella® showed more acute kidney injury (AKI) with the need for dialysis (71% vs. 21%, p=0.09). Conclusion: From our data, concomitant Impella® support might increase survival and successful ECMO weaning in eCPR patients. Treatment associated complications such as AKI were more common in this highly selected patient group. Further studies with larger numbers are necessary to evaluate concomitant LV-unloading’s clinical relevance in eCPR patients, using an Impella® device.

BackgroundWith the “Artemis”-mission mankind will return to the Moon by 2024. Prolonged periods in space will not only present physical and psychological challenges to the astronauts, but also pose risks concerning the medical treatment capabilities of the crew. So far, no guideline exists for the treatment of severe medical emergencies in microgravity. We, as a international group of researchers related to the field of aerospace medicine and critical care, took on the challenge and developed a an evidence-based guideline for the arguably most severe medical emergency – cardiac arrest.MethodsAfter the creation of said international group, PICO questions regarding the topic cardiopulmonary resuscitation in microgravity were developed to guide the systematic literature research. Afterwards a precise search strategy was compiled which was then applied to “MEDLINE”. Four thousand one hundred sixty-five findings were retrieved and consecutively screened by at least 2 reviewers. This led to 88 original publications that were acquired in full-text version and then critically appraised using the GRADE methodology. Those studies formed to basis for the guideline recommendations that were designed by at least 2 experts on the given field. Afterwards those recommendations were subject to a consensus finding process according to the DELPHI-methodology.ResultsWe recommend a differentiated approach to CPR in microgravity with a division into basic life support (BLS) and advanced life support (ALS) similar to the Earth-based guidelines. In immediate BLS, the chest compression method of choice is the Evetts-Russomano method (ER), whereas in an ALS scenario, with the patient being restrained on the Crew Medical Restraint System, the handstand method (HS) should be applied. Airway management should only be performed if at least two rescuers are present and the patient has been restrained. A supraglottic airway device should be used for airway management where crew members untrained in tracheal intubation (TI) are involved.DiscussionCPR in microgravity is feasible and should be applied according to the Earth-based guidelines of the AHA/ERC in relation to fundamental statements, like urgent recognition and action, focus on high-quality chest compressions, compression depth and compression-ventilation ratio. However, the special circumstances presented by microgravity and spaceflight must be considered concerning central points such as rescuer position and methods for the performance of chest compressions, airway management and defibrillation.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in clinical practice and is known to be associated with significant morbidity and mortality. Previous studies suggested a link between inflammation and AF by findings of increased inflammatory markers in AF patients. However, it has not been finally clarified whether inflammation is a systemic or a local phenomenon reflecting an active inflammatory process in the heart. To address this subject, human left atrial appendage tissues were obtained from 10 patients who underwent cardiac surgery and subjected to immunohistochemical analysis. The number of inflammatory CD3-positive T cells significantly increased from patients with sinus rhythm to paroxysmal AF and persistent AF, respectively. Interestingly, in patients with persistent AF, these cells were frequently arranged in small clusters. Subsequently, the number of inflammatory CD3-positive T cells decreased and was significantly lower in patients with permanent AF than in patients with persistent AF. Inflammatory CD20-positive B cells could only be detected very occasionally in all AF subgroups and were not locatable in patients with SR. Hence, our data emphasize the potential prominent role of the cellular component of the immune system in the development and perpetuation of AF.

Background. Sepsis is defined as a life-threatening organ dysfunction due to a dysregulated host response to infection. Sepsis is the dominant cause of acute kidney injury (AKI), accounting for nearly 50% of episodes of acute renal failure. Signaling cascades and pathways within the kidney are largely unknown and analysis of these molecular mechanisms may enhance knowledge on pathophysiology and possible therapeutic options.Material and Methods. 26 male Wistar rats were assigned to either a sham group (control,N=6) or sepsis group (N=20; cecal ligature and puncture model, 24 and 48 hours after CLP). Surviving rats (n=12) were decapitated at 24 hours (early phase;n=6) or 48 hours (late phase;n=6) after CLP and kidneys removed for proteomic analysis. 2D-DIGE and DeCyder 2D software (t-test,P<0.01) were used for analysis of significantly regulated protein spots. MALDI-TOF in combination with peptide mass fingerprinting (PMF) as well as Western Blot analysis was used for protein identification. Bioinformatic network analyses (STRING, GeneMania, and PCViz) were used to describe protein-protein interactions.Results. 12 spots were identified with significantly altered proteins (P<0.01) in the three analyzed groups. Two spots could not be identified. Four different proteins were found significantly changed among the groups: major urinary protein (MUP5), cytochrome c oxidase subunit B (COX5b), myosin-6 (MYH6), and myosin-7 (MYH7). A significant correlation with the proteins was found for mitochondrial energy production and electron transport.Conclusions. COX5B could be a promising biomarker candidate since a significant association was found during experimental sepsis in the present study. For future research, COX5B should be evaluated as a biomarker in both human urine and serum to identify sepsis.

Because of a technical error, the code corresponding to the outcome for the Basir et al. cohort was mis-implemented in the original version of our article. Characteristics of the cohort are in fact the followings.

By the end of the year 2016, approximately 3 billion people worldwide travelled by commercial air transport. Between 1 out of 14,000 and 1 out of 50,000 passengers will experience acute medical problems/emergencies during a flight (i.e., in-flight medical emergency). Cardiac arrest accounts for 0.3% of all in-flight medical emergencies. So far, no specific guideline exists for the management and treatment of in-flight cardiac arrest (IFCA). A task force with clinical and investigational expertise in aviation, aviation medicine, and emergency medicine was created to develop a consensus based on scientific evidence and compiled a guideline for the management and treatment of in-flight cardiac arrests. Using the GRADE, RAND, and DELPHI methods, a systematic literature search was performed in PubMed. Specific recommendations have been developed for the treatment of IFCA. A total of 29 specific recommendations for the treatment and management of in-flight cardiac arrests were generated. The main recommendations included emergency equipments as well as communication of the emergency. Training of the crew is of utmost importance, and should ideally have a focus on CPR in aircraft. The decision for a diversion should be considered very carefully.

Correction Volume: 44 Issue: 11 Pages: 2022-2023 DOI: 10.1007/s00134-018-5372-9 Catecholamines have been the mainstay of pharmacological treatment of cardiogenic shock (CS). Recently, use of epinephrine has been associated with detrimental outcomes. In the present study we aimed to evaluate the association between epinephrine use and short-term mortality in all-cause CS patients. We performed a meta-analysis of individual data with prespecified inclusion criteria: (1) patients in non-surgical CS treated with inotropes and/or vasopressors and (2) at least 15% of patients treated with epinephrine administrated alone or in association with other inotropes/vasopressors. The primary outcome was short-term mortality. Fourteen published cohorts and two unpublished data sets were included. We studied 2583 patients. Across all cohorts of patients, the incidence of epinephrine use was 37% (17-76%) and short-term mortality rate was 49% (21-69%). A positive correlation was found between percentages of epinephrine use and short-term mortality in the CS cohort. The risk of death was higher in epinephrine-treated CS patients (OR [CI] = 3.3 [2.8-3.9]) compared to patients treated with other drug regimens. Adjusted mortality risk remained striking in epinephrine-treated patients (n = 1227) (adjusted OR = 4.7 [3.4-6.4]). After propensity score matching, two sets of 338 matched patients were identified and epinephrine use remained associated with a strong detrimental impact on short-term mortality (OR = 4.2 [3.0-6.0]). In this very large cohort, epinephrine use for hemodynamic management of CS patients is associated with a threefold increase of risk of death.

We present a theoretical first-principles investigation of the structure and lattice dynamics of several layered semiconductors. The equilibrium structure as obtained by minimization of the total energy of the bulk materials is in good agreement with experiment. Furthermore, we have investigated the surface of these materials in order to obtain information on the van der Waals epitaxial growth. We found that the relaxed atomic positions at the surface deviate from the ideal ones in the bulk by less than 1%, which is obviously a consequence of the weak interlayer forces. Additionally, bulk phonon-dispersion curves have been calculated along several high symmetry directions within the density-functional perturbation theory (DFPT). The weak interlayer interaction makes the vibrational properties of the bulk very similar to those of the surface. In fact, our ab initio calculations for the bulk reproduce well both the experimental bulk phonon frequencies obtained by inelastic neutron scattering and the experimental surface phonon dispersion measured with inelastic He-atom scattering (HAS).