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Background After insertion of a central venous catheter (CVC) the catheter position must be controlled and a pneumothorax ruled out. Objective The aim was to examine whether the use of two standard acoustic windows known from emergency sonography examination techniques is feasible to 1) verify the correct intravenous localization and direction of the guidewire before final CVC insertion and 2) correctly predict the required CVC length for positioning of the catheter tip in the lower third of the superior vena cava. Material and methods This single center prospective observational study included adult patients (age ≥18 years) with an indication for CVC insertion after institutional ethics approval was obtained. Puncture sites were restricted to bilateral internal jugular and subclavian veins and except for duplicate examinations no further exclusion criteria were defined. After vessel puncture and insertion of the guidewire, the vena cava was displayed by an additional ultrasound examiner (sector scanner 1.5-3.6 MHz) using the transhepatic or subcostal acoustic window to localize the guidewire. For positioning of the CVC tip, the required catheter length in relation to the cavoatrial junction was measured using the guidewire marks during slow retraction and consecutive disappearance of the J‑shaped guidewire tip from each acoustic window. From the resulting insertion length of the guidewire 4 cm was subtracted for the transhepatic and 2 cm for the subcostal window under the assumption that this length correlates to the distance from the cavoatrial junction. The CVC was finally inserted and a chest radiograph was performed for radiological verification of the CVC position. Results Of 100 included patients, 94 could finally be analyzed. The guidewire could be identified in the vena cava in 91 patients (97%) within a time period of 2.2 ± 1.9 min. In three patients, the wire could not be visualized, although two catheters had the correct position, while one catheter was incorrectly positioned in the opposite axillary vein. In the second study part, positioning of the CVC was evaluated in 44 of the 94 patients. In 5 of these 44 patients, the correct direction and disappearance of the guidewire from the acoustic window could also be reliably visualized; however, with the left subclavian vein as the puncture site, the respective catheters were up to 6 cm too short for correct positioning. Thus, these 5 patients were excluded from this analysis. In the remaining 39 patients, the position of the CVC tip was optimally located in the lower third of the superior vena cava according to the chest radiograph in 20 patients (51%), while it was relatively too high in 5 patients (13%) and too low (entrance of the right atrium) in 9 patients. In the other 5 patients, disappearance of the guidewire from the acoustic window was not definitely detectable. Conclusion The presented intraprocedural ultrasound-based method using two standard acoustic windows is reliable for verification of the correct intravenous location and direction of the guidewire even before dilatation of the vessel puncture site for insertion of the catheter. Furthermore, the method allows the clinically acceptable measurement of the required length for catheter positioning. A chest radiograph can be waived provided the ultrasound examination (identification of the guidewire and exclusion of puncture-related complications such as pneumothorax) is unambiguous.

The current review focuses on recent clinical evidence and updated guideline recommendations on the effects of enteral vs. parenteral nutrition in adult critically ill patients with (septic) shock.The largest multicenter randomized-controlled trial showed that the route of nutrient supply was unimportant for 28-day and 90-day mortality, infectious morbidity and length of stay in mechanically ventilated patients with shock. The enteral route, however, was associated with lower macronutrient intake and significantly higher frequency of hypoglycemia and moderate-to-severe gastrointestinal complications. Integrating these findings into recent meta-analyses confirmed that the route per se has no effect on mortality and that interactions with (infectious) morbidity are inconsistent or questionable.The strong paradigm of favoring the enteral over the parenteral route in critically ill patients has been challenged. As a consequence, updated guidelines recommend withholding enteral nutrition in patients with uncontrolled shock. It is still unclear, however, whether parenteral nutrition is advantageous in patients with shock although benefits are conceivable in light of less gastrointestinal complications. Thus far, no guideline has addressed indications for parenteral nutrition in these patients. By considering recent scientific evidence, specific guideline recommendations, and expert opinions, we present a clinical algorithm that may facilitate decision-making when feeding critically ill patients with shock.

BACKGROUND: Gastrointestinal (GI) dysfunction is frequent in the critically ill but can be overlooked as a result of the lack of standardization of the diagnostic and therapeutic approaches. We aimed to develop a research agenda for GI dysfunction for future research. We systematically reviewed the current knowledge on a broad range of subtopics from a specific viewpoint of GI dysfunction, highlighting the remaining areas of uncertainty and suggesting future studies. METHODS: This systematic scoping review and research agenda was conducted following successive steps: (1) identify clinically important subtopics within the field of GI function which warrant further research; (2) systematically review the literature for each subtopic using PubMed, CENTRAL and Cochrane Database of Systematic Reviews; (3) summarize evidence for each subtopic; (4) identify areas of uncertainty; (5) formulate and refine study proposals that address these subtopics; and (6) prioritize study proposals via sequential voting rounds. RESULTS: Five major themes were identified: (1) monitoring, (2) associations between GI function and outcome, (3) GI function and nutrition, (4) management of GI dysfunction and (5) pathophysiological mechanisms. Searches on 17 subtopics were performed and evidence summarized. Several areas of uncertainty were identified, six of them needing consensus process. Study proposals ranked among the first ten included: prevention and management of diarrhoea; management of upper and lower feeding intolerance, including indications for post-pyloric feeding and opioid antagonists; acute gastrointestinal injury grading as a bedside tool; the role of intra-abdominal hypertension in the development and monitoring of GI dysfunction and in the development of non-occlusive mesenteric ischaemia; and the effect of proton pump inhibitors on the microbiome in critical illness. CONCLUSIONS: Current evidence on GI dysfunction is scarce, partially due to the lack of precise definitions. The use of core sets of monitoring and outcomes are required to improve the consistency of future studies. We propose several areas for consensus process and outline future study projects., SCOPUS: ar.j, info:eu-repo/semantics/published

Objective Static or quasi-static pressure-volume (P-V ) curves can be used to determine the lung mechanical properties of patients suffering from acute respiratory distress syndrome (ARDS). According to the traditional interpretation, lung recruitment occurs mainly below the lower point of maximum curvature (LPMC) of the inflation P-V curve. Although some studies have questioned this assumption, setting of positive end-expiratory pressure 2 cmH2O above the LPMC was part of a 'lung-protective' ventilation strategy successfully applied in several clinical trials. The aim of our study was to quantify the amount of unrecruited lung at different clinically relevant points of the P-V curve. Approach P-V curves and electrical impedance tomography (EIT) data from 30 ARDS patients were analysed. We determined the regional opening pressures for every EIT image pixel and fitted the global P-V curves to five sigmoid model equations to determine the LPMC, inflection point (IP) and upper point of maximal curvature (UPMC). Points of maximal curvature and IP were compared between the models by one-way analysis of variance (ANOVA). The percentages of lung pixels remaining closed ('unrecruited lung') at LPMC, IP and UPMC were calculated from the number of lung pixels exhibiting regional opening pressures higher than LPMC, IP and UPMC and were also compared by one-way ANOVA. Main results As results, we found a high variability of LPMC values among the models, a smaller variability of IP and UPMC values. We found a high percentage of unrecruited lung at LPMC, a small percentage of unrecruited lung at IP and no unrecruited lung at UPMC. Significance Our results confirm the notion of ongoing lung recruitment at pressure levels above LPMC for all investigated model equations and highlight the importance of a regional assessment of lung recruitment in patients with ARDS.

Background : Delirium is a common complication in patients on Intensive Care Units (ICU). Caring interventions such as early mobilization are effective in prevention and treatment of delirium, but are recommended during daytime. It may be effective in the night, too. Method : The aim of this study was to prove the effect of mobilization in the evening to prevent or treat ICU patients from delirium. The design was a multicentric, randomized, controlled trial in 5 mixed ICUs over a period of 2 weeks with max. 28 days follow-up. Patients in the intervention group were mobilized onto the edge of the bed or more between 9:00 and 11:00 p.m. by an additional mobilization team, following safety criteria. Patients in the control group received usual care. Primary outcome parameter was the duration of a delirium. Secondary parameters were presence of delirium, mortality, duration of mechanical ventilation (MV) and stay, feasibility, and mobilization-related complications. Results : In summary, n=69 patients could be analysed (intervention n=36, control n=33). Due to limited resources, the trial was stopped and reached 62% of targeted sample size. Mobilization in the evening did not significantly reduce duration of existing delirium, delirium presence, length of MV or days in ICU and hospital for 28 days follow-up. In an unplanned post-hoc analysis, mobilization in the evening prevented patients from delirium in the first four days (6 (16.7%) vs. 13 (39.4%), p=0.032), with a number needed to treat of 5. The intervention was feasible in 71.7% of eligible patients, with 13.6% unwanted safety events. Conclusions : In a mixed ICU population, mobilization in the evening did not show a reduction in duration of delirium, MV or length of stay, but a reduction in the incidence of early onset delirium. Mobilization between 9:00 and 11:00 pm. by an interprofessional mobilization team may prevent patients from delirium. The intervention was feasible, safe, and accepted by most patients.

SCOPUS: le.j, info:eu-repo/semantics/published

Background Evaluation of analgesia and antinociception during anaesthesia is still a challenging issue and routinely based on indirect and non-specific signs such as movement, tachycardia, or lacrimation. Recently, the surgical pleth index (SPI) derived by finger plethysmography was introduced to detect nociceptive stimulation during anaesthesia. While SPI guidance reduced the number of unwanted events during total i.v. anaesthesia (TIVA), the impact of SPI during volatile-based anaesthesia with intermittent opioid administration has not yet been elucidated. Methods Ninety-four patients were randomized into either SPI-guided analgesia or standard practice (Control). In both groups, anaesthesia was maintained with sevoflurane to keep bispectral index values between 40 and 60. In the SPI group, patients received a sufentanil bolus (10 μg) whenever SPI value increased above 50, whereas in the control group, sufentanil was administered according to standard clinical practice. The number of unwanted somatic events, haemodynamics, sufentanil consumption, and recovery times were recorded. Results The incidence of intraoperative unwanted somatic events was comparable between the groups (P=0.89). No significant differences with respect to hypotensive or hypertensive events were found. The mean (95% confidence interval) sufentanil consumption was non-significantly (P=0.07) reduced in the SPI group, 0.64 (0.57–0.71) vs 0.78 (0.64–0.91) µg min−1. Recovery times were comparable between the groups. Conclusions Sufentanil administration guided by SPI during sevoflurane anaesthesia is clinically feasible. In contrast to TIVA, it did not improve anaesthesia conduct with respect to unwanted somatic events, haemodynamic stability, sufentanil consumption, emergence time, or post-anaesthesia care unit care. Therefore, we conclude that anaesthesia regimen has an impact on beneficial effects by SPI guidance. Clinical trial registration NCT01525537. (Registered at Clinicaltrials.gov .)

Background Enteral nutrition (EN) is recommended as the preferred route for early nutrition therapy in critically ill adults over parenteral nutrition (PN). A recent large randomized controlled trial (RCT) showed no outcome differences between the two routes. The objective of this systematic review was to evaluate the effect of the route of nutrition (EN versus PN) on clinical outcomes of critically ill patients. Methods An electronic search from 1980 to 2016 was performed identifying relevant RCTs. Individual trial data were abstracted and methodological quality of included trials scored independently by two reviewers. The primary outcome was overall mortality and secondary outcomes included infectious complications, length of stay (LOS) and mechanical ventilation. Subgroup analyses were performed to examine the treatment effect by dissimilar caloric intakes, year of publication and trial methodology. We performed a test of asymmetry to assess for the presence of publication bias. Results A total of 18 RCTs studying 3347 patients met inclusion criteria. Median methodological score was 7 (range, 2–12). No effect on overall mortality was found (1.04, 95 % CI 0.82, 1.33, P = 0.75, heterogeneity I2 = 11 %). EN compared to PN was associated with a significant reduction in infectious complications (RR 0.64, 95 % CI 0.48, 0.87, P = 0.004, I2 = 47 %). This was more pronounced in the subgroup of RCTs where the PN group received significantly more calories (RR 0.55, 95 % CI 0.37, 0.82, P = 0.003, I2 = 0 %), while no effect was seen in trials where EN and PN groups had a similar caloric intake (RR 0.94, 95 % CI 0.80, 1.10, P = 0.44, I2 = 0 %; test for subgroup differences, P = 0.003). Year of publication and methodological quality did not influence these findings; however, a publication bias may be present as the test of asymmetry was significant (P = 0.003). EN was associated with significant reduction in ICU LOS (weighted mean difference [WMD] -0.80, 95 % CI −1.23, −0.37, P = 0.0003, I2 = 0 %) while no significant differences in hospital LOS and mechanical ventilation were observed. Conclusions In critically ill patients, the use of EN as compared to PN has no effect on overall mortality but decreases infectious complications and ICU LOS. This may be explained by the benefit of reduced macronutrient intake rather than the enteral route itself. Electronic supplementary material The online version of this article (doi:10.1186/s13054-016-1298-1) contains supplementary material, which is available to authorized users.

Introduction Patients with acute respiratory distress syndrome (ARDS) typically show a high degree of ventilation inhomogeneity, which is associated with morbidity and unfavorable outcomes. Electrical impedance tomography (EIT) is able to detect ventilation inhomogeneity, but it is unclear which method for defining the region of interest (ROI) should be used for this purpose. The aim of our study was to compare the functional region of interest (fROI) method to both the lung area estimation method (LAEM) and no ROI when analysing global parameters of ventilation inhomogeneity. We assumed that a good method for ROI determination would lead to a high discriminatory power for ventilation inhomogeneity, as defined by the area under the receiver operating characteristics curve (AUC), comparing patients suffering from ARDS and control patients without pulmonary pathologies. Methods We retrospectively analysed EIT data from 24 ARDS patients and 12 control patients without pulmonary pathology. In all patients, a standardized low-flow-pressure volume maneuver had been performed and was used for EIT image generation. We compared the AUC for global inhomogeneity (GI) index and coefficient of variation (CV) between ARDS and control patients using all EIT image pixels, the fROI method and the LAEM for ROI determination. Results When analysing all EIT image pixels, we found an acceptable AUC both for the GI index (AUC = 0.76; 95% confidence interval (CI) 0.58–0.94) and the CV (AUC = 0.74; 95% CI 0.55–0.92). With the fROI method, we found a deteriorating AUC with increasing threshold criteria. With the LAEM, we found the best AUC both for the GI index (AUC = 0.89; 95% CI 0.78–1.0) and the CV (AUC = 0.89; 95% CI 0.78–1.0) using a threshold criterion of 50% of the maximum tidal impedance change. Conclusion In the assessment of ventilation inhomogeneity with EIT, functional regions of interest obscure the difference between patients with ARDS and control patients without pulmonary pathologies. The LAEM is preferable to the fROI method when assessing ventilation inhomogeneity.

The global inhomogeneity (GI) index is a parameter of ventilation inhomogeneity that can be calculated from images of tidal ventilation distribution obtained by electrical impedance tomography (EIT). It has been suggested that the GI index may be useful for individual adjustment of positive end-expiratory pressure (PEEP) and for guidance of ventilator therapy. The aim of the present work was to assess the influence of tidal volume (VT) on the GI index values. EIT data from 9 patients with acute respiratory distress syndrome ventilated with a low and a high VT of 5 ± 1 (mean ± SD) and 9 ± 1 ml kg(-1) predicted body weight at a high and a low level of PEEP (PEEPhigh, PEEPlow) were analyzed. PEEPhigh and PEEPlow were set 2 cmH2O above and 5 cmH2O below the lower inflection point of a quasi-static pressure volume loop, respectively. The lower inflection point was identified at 8.1 ± 1.4 (mean ± SD) cmH2O, resulting in a PEEPhigh of 10.1 ± 1.4 and a PEEPlow of 3.1 ± 1.4 cmH2O. At PEEPhigh, we found no significant trend in GI index with low VT when compared to high VT (0.49 ± 0.15 versus 0.44 ± 0.09, p = 0.13). At PEEPlow, we found a significantly higher GI index with low VT compared to high VT (0.66 ± 0.19 versus 0.59 ± 0.17, p = 0.01). When comparing the PEEP levels, we found a significantly lower GI index at PEEPhigh both for high and low VT. We conclude that high VT may lead to a lower GI index, especially at low PEEP settings. This should be taken into account when using the GI index for individual adjustment of ventilator settings.

To provide an overview on the recent literature regarding metabolism during sepsis and outcome-related effects of nutrition therapy in septic patients. The question when and how these patients should be fed with respect to macronutrient intake is elaborated.Although the incidence of severe sepsis has steadily increased over the past years, still no strong evidence is available with respect to the role of energy and protein provision in these patients. On the basis of recent large randomized trials in mixed patient populations, the updated sepsis guidelines recommend early but limited nutrition via the enteral route rather than targeted feeding. Lately, the results of a large trial challenged the importance of the route of feeding on the clinical outcome of critically ill patients. Four post-hoc analyses of prospective randomized trials including a large number of severely septic patients yielded conflicting results. One reported significant mortality reduction with near-target calorie and protein intake by exclusive enteral nutrition, whereas the second showed an advantage of enteral compared to combined nutrition, albeit resulting in a lower calorie and protein provision. The other two analyses found no association at all of either lower or higher daily caloric or protein intake, respectively, with clinical outcomes.In the absence of strong clinical evidence, pathophysiological findings are discussed and nutritional strategies for septic patients derived. Future studies should explore the individual response to specific exogenous supply of macronutrients and micronutrients in the acute and persistent phase of severe systemic inflammation.

A pumpless interventional arteriovenous lung assist device (iLA) facilitates the removal of carbon dioxide from the blood and is used as part of the lung-protective ventilation strategy in patients with acute respiratory distress syndrome (ARDS). In case of bacterial infection, delayed antimicrobial therapy increases the mortality in this group of high-risk critically ill patients, whereas overtreatment promotes bacterial resistance and leads to increased drug toxicity and costs. Besides clinical signs and symptoms, antimicrobial treatment is based on the kinetics of biomarkers such as procalcitonin (PCT). We hereby report an up to 10-fold increase in PCT serum concentrations in four mechanically ventilated patients with ARDS detected within 12-20 hours after iLA implantation in the absence of any infection. Procalcitonin concentrations returned to nearly baseline values in all patients on the fourth day after iLA implantation. We discuss the possible mechanisms of PCT induction in this specific patient population and recommend the onset of antibiotics administration after iLA implantation to be carefully considered in the context of other clinical findings and not solely based on the PCT kinetics. Repeated PCT measurements in short time intervals should be performed in these patients.

INTRODUCTION Acid sphingomyelinase is involved in lipid signalling pathways and regulation of apoptosis by the generation of ceramide and plays an important role during the host response to infectious stimuli. It thus has the potential to be used as a novel diagnostic marker in the management of critically ill patients. The objective of our study was to evaluate acid sphingomyelinase serum activity (ASM) as a diagnostic and prognostic marker in a mixed intensive care unit population before, during, and after systemic inflammation. METHODS 40 patients admitted to the intensive care unit at risk for developing systemic inflammation (defined as systemic inflammatory response syndrome plus a significant procalcitonin [PCT] increase) were included. ASM was analysed on ICU admission, before (PCT before), during (PCT peak) and after (PCT low) onset of SIRS. Patients undergoing elective surgery served as control (N = 8). Receiver-operating characteristics curves were computed. RESULTS ASM significantly increased after surgery in the eight control patients. Patients from the intensive care unit had significantly higher ASM on admission than control patients after surgery. 19 out of 40 patients admitted to the intensive care unit developed systemic inflammation and 21 did not, with no differences in ASM between these two groups on admission. In patients with SIRS and PCT peak, ASM between admission and PCT before was not different, but further increased at PCT peak in non-survivors and was significantly higher at PCT low compared to survivors. Survivors exhibited decreased ASM at PCT peak and PCT low. Receiver operating curve analysis on discrimination of ICU mortality showed an area under the curve of 0.79 for ASM at PCT low. CONCLUSIONS In summary, ASM was generally higher in patients admitted to the intensive care unit compared to patients undergoing uncomplicated surgery. ASM did not indicate onset of systemic inflammation. In contrast to PCT however, it remained high in non-surviving ICU patients after systemic inflammation.

In acute lung injury (ALI), the application of positive end-expiratory pressure (PEEP) is known to prevent the alveoli from cyclic collapse and reopening and to homogenize ventilation. The setting of adequate PEEP could be optimized by the knowledge of regional lung opening and closing pressures at the bedside. The aim of our study was to determine regional opening and closing pressures in ventilated patients by electrical impedance tomography (EIT).Eight patients with healthy lungs and 18 patients with ALI were studied. A low-flow inflation and deflation maneuver with constant gas flow was performed. Regional opening and closing pressures were calculated for every pixel of the EIT scan. These pressures were defined as those values of global airway pressure at which the lung areas opened up or started to close.Injured lungs exhibited significantly higher regional opening pressures compared with healthy lungs (P.05). In ALI, significantly higher opening pressures were found in the dependent lung regions. Regional closing pressures did not significantly differ between healthy and injured lungs.Regional lung opening and closing pressures can be assessed by EIT. This information may facilitate the setting of adequate PEEP levels in patients in future.

Background Lung tissue of patients with acute respiratory distress syndrome (ARDS) is heterogeneously damaged and prone to develop atelectasis. During inflation, atelectatic regions may exhibit alveolar recruitment accompanied by prolonged filling with air in contrast to regions with already open alveoli with a fast increase in regional aeration. During deflation, derecruitment of injured regions is possible with ongoing loss in regional aeration. The aim of our study was to assess the dynamics of regional lung aeration in mechanically ventilated patients with ARDS and its dependency on positive end-expiratory pressure (PEEP) using electrical impedance tomography (EIT). Methods Twelve lung healthy and twenty ARDS patients were examined by EIT during sustained step increases in airway pressure from 0, 8 and 15 cm H2O to 35 cm H2O and during subsequent step decrease to the corresponding PEEP. Regional EIT waveforms in the ventral and dorsal lung regions were fitted to bi-exponential equations. Regional fast and slow respiratory time constants and the sizes of the fast and slow compartments were subsequently calculated. Results ARDS patients exhibited significantly lower fast and slow time constants than the lung healthy patients in ventral and dorsal regions. The time constants were significantly affected by PEEP and differed between the regions. The size of the fast compartment was significantly lower in ARDS patients than in patients with healthy lung under all studied conditions. Conclusion These results show that regional lung mechanics can be assessed by EIT. They reflect the lower respiratory system compliance of injured lungs and imply more pronounced regional recruitment and derecruitment in ARDS patients.