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.

[Postdural puncture headache after neuraxial anesthesia: incidence and risk factors]. / Postpunktioneller Kopfschmerz nach rückenmarknahen Anästhesieverfahren: Inzidenz und Risikofaktoren.

BACKGROUND/OBJECTIVE: Postdural puncture headache (PDPH) is a severe complication after spinal anesthesia. The aim of this study was to investigate the incidence of PDPH in two different operative cohorts and to identify risk factors for its occurrence as well as to analyze its influence on the duration of hospital stay. MATERIAL AND METHODS: In a retrospective study over a period of 3 years (2010-2012), 341 orthopedic surgery (ORT) and 2113 obstetric (OBS) patients were evaluated after spinal anesthesia (SPA). Data were statistically analyzed using (SPSS-23) univariate analyses with the Mann-Whitney U­test, χ2-test and Student's t-test as well as logistic regression analysis. RESULTS: The incidence of PDPH was 5.9% in the ORT cohort and 1.8% in the OBS cohort. Patients with PDPH in the ORT cohort were significantly younger (median 38 years vs. 47 years, p = 0.011), had a lower body weight (median 70.5 kg vs. 77 kg, p = 0.006) and a lower body mass index (median 23.5 vs. 25.2, p = 0.037). Body weight (odds ratio (97.5 % Confidence Intervall [CI]), OR 0.956: 97.5% CI 0.920-0.989, p = 0.014) as well as age (OR 0.963: 97.5% CI 0.932-0.991, p = 0.015) were identified as independent risk factors for PDPH. In OBS patients, PDPH occurred more frequently after spinal epidural anesthesia than after combined spinal epidural anesthesia (8.6% vs. 1.2%, p < 0.001) and the type of neuraxial anesthesia was identified as an independent risk factor for PDPH (OR 0.049; 97.5% CI 0.023-0.106, p < 0.001). In both groups the incidence of PDPH was associated with a longer hospital stay (ORT patients 4 days vs. 2 days, p = 0.001; OBS patients 6 days vs. 4 days, p < 0.0005). CONCLUSION: The incidence of PDPH was different in the two groups with a higher incidence in the ORT but considerably lower than in the literature. Age, constitution and type of neuraxial anesthesia were identified as risk factors of PDPH. Considering the functional imitations (mobilization, neonatal care) and a longer hospital stay, future studies should investigate the impact of an early treatment of PDPH.

Why does a point of care guided transfusion algorithm not improve blood loss and transfusion practice in patients undergoing high-risk cardiac surgery? A prospective randomized controlled pilot study.

BACKGROUND: Adult cardiac surgery is often complicated by elevated blood losses that account for elevated transfusion requirements. Perioperative bleeding and transfusion of blood products are major risk factors for morbidity and mortality. Timely diagnostic and goal-directed therapies aim at the reduction of bleeding and need for allogeneic transfusions. METHODS: Single-centre, prospective, randomized trial assessing blood loss and transfusion requirements of 26 adult patients undergoing elective cardiac surgery at high risk for perioperative bleeding. Primary endpoint was blood loss at 24 h postoperatively. Random assignment to intra- and postoperative haemostatic management following either an algorithm based on conventional coagulation assays (conventional group: platelet count, aPTT, PT, fibrinogen) or based on point-of-care (PoC-group) monitoring, i.e. activated rotational thromboelastometry (ROTEM®) combined with multiple aggregometry (Multiplate®). Differences between groups were analysed using nonparametric tests for independent samples. RESULTS: The study was terminated after interim analysis (n = 26). Chest tube drainage volume was 360 ml (IQR 229-599 ml) in the conventional group, and 380 ml (IQR 310-590 ml) in the PoC-group (p = 0.767) after 24 h. Basic patient characteristics, results of PoC coagulation assays, and transfusion requirements of red blood cells and fresh frozen plasma did not differ between groups. Coagulation results were comparable. Platelets were transfused in the PoC group only. CONCLUSION: Blood loss via chest tube drainage and transfusion amounts were not different comparing PoC- and central lab-driven transfusion algorithms in subjects that underwent high-risk cardiac surgery. Routine PoC coagulation diagnostics do not seem to be beneficial when actual blood loss is low. High risk procedures might not suffice as a sole risk factor for increased blood loss. TRIAL REGISTRATION: NCT01402739 , Date of registration July 26, 2011.

Associations of postoperative mortality with the time of day, week and year.

Studies that have investigated circadian, weekday and seasonal variation in postoperative mortality have been relatively small or have been for scheduled surgery. We retrospectively tested a large mixed surgical cohort from a German tertiary care university hospital for the presence of cyclical variation in all-cause in-hospital mortality after operations performed between 2006 and 2013. We analysed mortality rates after 247,475 operations, adjusted for age, sex, comorbidities, location, urgency and duration of the surgery, and intra-operative blood transfusions. The mortality odds ratio (95%CI) after operations started in the morning (08:00-11:00) were lowest, 0.73 (0.66-0.80), p < 0.001 and highest for operations started in the afternoon (13:00-17:00), 1.29 (1.18-1.40), p < 0.001. Mortality at the weekend was the same as during the week. There was no seasonal variation in mortality, p = 0.12. However, the interference of four-yearly and ten-monthly cycle amplitudes resulted in higher mortality odds ratio (95%CI) in winter 2008-2009, 1.41 (1.18-1.69), p < 0.001, and lower mortality in spring 2011 and 2012, 0.70 (0.56-0.85) and 0.67 (0.53-0.85), p < 0.001 and p = 0.001, respectively. The ability to predict cyclical phenomena would facilitate the design of interventional studies, aimed at reducing mortality following surgery in the afternoon and when cycles interfere constructively.

[Tranexamic acid in the German emergency medical service : A national survey]. / Vorhaltung von Tranexamsäure im deutschen Rettungsdienst : Eine nationale Umfrage.

BACKGROUND: Trauma-induced coagulopathy, one of the leading causes of trauma-related death, is detected in about one of four trauma patients upon hospital admission. The current European Management of Major Bleeding and Coagulopathy Following Trauma guidelines, published in 2013, recommend that tranexamic acid (TXA) be administered as early as possible to inhibit hyperfibrinolysis (grade of recommendation (GoR 1A)). Furthermore, it is suggested that protocols for the management of patients with bleeding or showing signs of bleeding include the administration of the first dose of TXA at the site of injury or during transportation to hospital (GoR 2C). There is no current data showing to what extent TXA is used in the pre-hospital settings in Germany. OBJECTIVES: This study aimed to collect data about the availability of TXA in the German emergency medical service (EMS). We tried to determine how many EMS stored and used TXA, under which circumstances the substance was used and whether any standard operating procedures (SOPs) were in use. The study also tried to determine what dosage recommendations exist. MATERIALS AND METHODS: Between 1 July and 31 August 2015, a total of 326 German emergency medical directors (EMDs) were asked to take part in a survey, which involved answering an online questionnaire. RESULTS: Altogether 163 EMD answered the questionnaire (response rate 50%). The results showed that 52.8% of EMDs stored TXA in their vehicles and 26% planned to do so in the future. The availability of TXA in the EMS has increased since 2010. Most EMDs stated that guidelines were the reason for this. SOPs existed in 17.4%. Dosage recommendations were defined by the EMDs in 76.7%. More than 80% of dosage recommendations followed the European guideline. CONCLUSION: The survey shows a widespread distribution of TXA in the German EMS, which has significantly increased between 2010 and 2015. However, nationwide distribution has not yet been established. This rise in distribution is interpreted as a reaction to national and European guidelines for the management of severe bleeding and trauma care. A remaining question is to determine which patients should be treated with TXA, as hyperfibrinolysis is not detectable at the site of injury.

Dynamic parameters of fluid responsiveness in the operating room : An analysis of intraoperative ventilation framework conditions.

BACKGROUND: Reliable assessment of fluid responsiveness with pulse pressure variation (PPV) depends on certain ventilation-related preconditions; however, some of these requirements are in contrast with recommendations for protective ventilation. OBJECTIVE: The aim of this study was to evaluate the applicability of PPV in patients undergoing non-cardiac surgery by retrospectively analyzing intraoperative ventilation data. MATERIAL AND METHODS: Intraoperative ventilation data from three large medical centers in Germany and Switzerland from January to December 2018 were extracted from electronic patient records and pseudonymized; 10,334 complete data sets were analyzed with respect to the ventilation parameters set as well as demographic and medical data. RESULTS: In 6.3% of the 3398 included anesthesia records, patients were ventilated with mean tidal volumes (mTV) > 8 ml/kg predicted body weight (PBW). These would qualify for PPV-based hemodynamic assessment, but the majority were ventilated with lower mTVs. In patients who underwent abdominal surgery (75.5% of analyzed cases), mTVs > 8 ml/kg PBW were used in 5.5% of cases, which did not differ between laparoscopic (44.9%) and open (55.1%) approaches. Other obstacles to the use of PPV, such as elevated positive end-expiratory pressure (PEEP) or increased respiratory rate, were also identified. Of all the cases 6.0% were ventilated with a mTV of > 8 ml/kg PBW and a PEEP of 5-10 cmH2O and 0.3% were ventilated with a mTV > 8 ml/kg PBW and a PEEP of > 10 cmH2O. CONCLUSION: The data suggest that only few patients meet the currently defined TV (of > 8 ml/kg PBW) for assessment of fluid responsiveness using PPV during surgery.

[Venous saturation : Between oxygen delivery and consumption]. / Venöse Sättigung : Zwischen Sauerstoffangebot und -verbrauch.

Venous saturation is an important parameter to assess the ratio between oxygen delivery and oxygen consumption for both intensive care medicine and during perioperative care. Mixed venous saturation (SvO2) is the most reliable parameter in this setting. Due to the high invasiveness of measuring mixed venous saturation, the less invasive central venous saturation (ScvO2) has been entrenched for determining the balance of oxygen delivery and consumption. However, central venous saturation is inferior compared to mixed venous saturation as it does not cover the lower part of the body, including splanchnic perfusion. Nevertheless, studies have shown that central venous saturation is a reliable marker for goal-directed therapy in intensive care medicine, especially in patients with septic or hemorrhagic shock. Furthermore, central venous saturation has deep impact as a prognostic factor concerning morbidity and mortality. It has to be mentioned that not only decreased venous saturations but also elevated venous saturations are associated with poor outcome. Besides mixed venous and central venous saturation, intensivists and anesthesiologists focus on the central venous-arterial pCO2 difference (dCO2). An elevated dCO2 is associated with poor outcome in patients after cardiac surgery or patients with sepsis. Yet, further investigations have to be performed to implement the dCO2 as a reliable marker in daily routine.

Back-calculating baseline creatinine overestimates prevalence of acute kidney injury with poor sensitivity.

AIM: Acute kidney injury (AKI) is diagnosed by a 50% increase in creatinine. For patients without a baseline creatinine measurement, guidelines suggest estimating baseline creatinine by back-calculation. The aim of this study was to evaluate different glomerular filtration rate (GFR) equations and different GFR assumptions for back-calculating baseline creatinine as well as the effect on the diagnosis of AKI. METHODS: The Modification of Diet in Renal Disease, the Chronic Kidney Disease Epidemiology (CKD-EPI) and the Mayo quadratic (MQ) equation were evaluated to estimate baseline creatinine, each under the assumption of either a fixed GFR of 75 mL min-1  1.73 m-2 or an age-adjusted GFR. Estimated baseline creatinine, diagnoses and severity stages of AKI based on estimated baseline creatinine were compared to measured baseline creatinine and corresponding diagnoses and severity stages of AKI. RESULTS: The data of 34 690 surgical patients were analysed. Estimating baseline creatinine overestimated baseline creatinine. Diagnosing AKI based on estimated baseline creatinine had only substantial agreement with AKI diagnoses based on measured baseline creatinine [Cohen's κ ranging from 0.66 (95% CI 0.65-0.68) to 0.77 (95% CI 0.76-0.79)] and overestimated AKI prevalence with fair sensitivity [ranging from 74.3% (95% CI 72.3-76.2) to 90.1% (95% CI 88.6-92.1)]. Staging AKI severity based on estimated baseline creatinine had moderate agreement with AKI severity based on measured baseline creatinine [Cohen's κ ranging from 0.43 (95% CI 0.42-0.44) to 0.53 (95% CI 0.51-0.55)]. CONCLUSION: Diagnosing AKI and staging AKI severity on the basis of estimated baseline creatinine in surgical patients is not feasible. Patients at risk for post-operative AKI should have a pre-operative creatinine measurement to adequately assess post-operative AKI.

Feasibility and influence of hTEE monitoring on postoperative management in cardiac surgery patients.

Monoplane hemodynamic TEE (hTEE) monitoring (ImaCor(®) ClariTEE(®)) might be a useful alternative to continuously evaluate cardiovascular function and we aimed to investigate the feasibility and influence of hTEE monitoring on postoperative management in cardiac surgery patients. After IRB approval we reviewed the electronic data of cardiac surgery patients admitted to our intensive care between 01/01/2012 and 30/06/2013 in a case-controlled matched-pairs design. Patients were eligible for the study when they presented a sustained hemodynamic instability postoperatively with the clinical need of an extended hemodynamic monitoring: (a) hTEE (hTEE group, n = 18), or (b) transpulmonary thermodilution (control group, n = 18). hTEE was performed by ICU residents after receiving an approximately 6-h hTEE training session. For hTEE guided hemodynamic optimization an institutional algorithm was used. The hTEE probe was blindly inserted at the first attempt in all patients and image quality was at least judged to be adequate. The frequency of hemodynamic examinations was higher (ten complete hTEE examinations every 2.6 h) in contrast to the control group (one examination every 8 h). hTEE findings, including five unexpected right heart failure and one pericardial tamponade, led to a change of current therapy in 89% of patients. The cumulative dose of epinephrine was significantly reduced (p = 0.034) and levosimendan administration was significantly increased (p = 0.047) in the hTEE group. hTEE was non-inferior to the control group in guiding norepinephrine treatment (p = 0.038). hTEE monitoring performed by ICU residents was feasible and beneficially influenced the postoperative management of cardiac surgery patients.

Preoperative depression and hospital length of stay in surgical patients.

BACKGROUND: The association of depression and hospital length of stay (LOS) has rarely been examined in surgical patients outside of cardiovascular surgery. This study investigates whether clinically significant preoperative depression shows an independent association with LOS in patients from various surgical fields after adjusting for age, gender and important somatic factors. METHODS: A total of 2624 surgical patients were included in this prospective observational study. Data were collected before the preoperative anesthesiological examination within a computer-assisted psychosocial self-assessment including screening for depression (Center for Epidemiologic Studies Depression Scale, CES-D). Data on peri- and postoperative somatic parameters were obtained from the electronic patient management system of the hospital six months after the preoperative assessment. RESULTS: LOS of patients with clinically significant depression (N.=296; median: 5 days, interquartile range: 3-8 days) was longer than LOS of patients without depression (N.=2328; median: 4 days, interquartile range: 2-6 days) (P<0.001). A multivariate logistic regression model with the binary dependent variable 'above versus below or equal to the median LOS' revealed that the significant association between depression and LOS persisted (OR: 1.822 [95% CI 1.360-2.441], P<0.001) when simultaneously including the covariates age, gender, ASA classification, Charlson Comorbidity Index, surgical field and POSSUM operative severity rating. CONCLUSION: Data suggest that the association of depression and LOS is independent of the impact of age, gender, surgical field, preoperative physical health, severity of medical comorbidity and extent of surgical procedure. Integration of depression therapy into routine care of surgical patients might be an option to improve outcomes.

[Patient safety in anesthesiology and intensive care medicine. Measures for improvement]. / Patientensicherheit in der Anästhesie und Intensivmedizin. Massnahmen zur Verbesserung.

Technical improvements as well as various strategies for error detection and error prevention have made intensive care medicine and anesthesiology a safe medical specialty. Due to the introduction of "Patient safety in the ICU: the Vienna declaration" of the European Society of Intensive Care Medicine (ESICM) from October 2009 and the "Helsinki declaration on patient safety" of the European Society of Anaesthesiology (ESA) and the European Board of Anaesthesiology (EBA) from June 2010, there are now specific recommendations for all hospitals in Europe concerning the safety measures that are considered to be of essential importance. Many of today's well-known safety strategies have been originally developed in non-medical environments, as for instance civil aviation. Such high reliability organizations may serve as examples in the medical domain. Critical incident reporting systems, crisis resource management and checklists, e.g. the World Health Organization (WHO) checklist, are safety approaches of this kind. In addition to these, standardized drug labelling, hand disinfection, techniques for patient handover and simulation-based training have been exemplarily selected for this article as measures that can increase patient safety.

Frequency shifts and lifetime changes of sodium atoms near rough metal surfaces.

Two-photon laser-induced fluorescence measurements of transition frequencies and lifetimes of laser-excited Na atoms are presented as a function of distance (2-3nm) to metal surfaces of different roughness. We characterized the surface roughness by fitting a Gaussian height-height correlation function to force microscopic data. An unusually small red shift of the Na transition frequency of a few hundred megahertz was observed. In the framework of a quantum-mechanical linear optical response formalism we fitted the lifetime and the frequency shift data simultaneously to obtain effective parameters of a selvedge dielectric function. In that way we are able to take into account both surface roughness and nonlocality, which in turn result in the observed small frequency shifts.