Evaluation of continuous ampicillin/sulbactam infusion in critically ill patients.

Continuous infusion (CI) of beta-lactam-antibiotics may improve pharmacodynamics in critically ill patients, but resulting concentrations have not been studied. Therapeutic drug monitoring is increasingly used to ensure antibiotic concentration. The aim of this study is to evaluate therapeutic ampicillin/sulbactam concentrations of a continuous infusion regimen. METHODS: Medical records of all patients admitted to ICU between January 2019 and December 2020 were retrospectively reviewed. Each patient received a 2/1 g ampicillin/sulbactam loading dose, followed by a continuous infusion of 8/4 g per 24 h. Ampicillin serum concentrations were measured. Main outcomes were reaching of plasma concentrations breakpoint defined by minimum inhibitory concentration (MIC at 8 mg/l) and 4-fold MIC (MIC at 32 mg/l) during steady state of CI. RESULTS: In 50 patients a total of 60 concentration measurements were performed. The first concentration was measured after a median of 29 h (IQR 21-61 h). Mean ampicillin concentration was 62.6 ± 39.1 mg/l. Furthermore, serum concentrations exceeded the defined MIC breakpoint in all measurements (100 %) and were above the 4-fold MIC in 43 analyses (71.1 %). However, patients suffering from acute kidney injury exhibited significant higher serum concentrations (81.1 ± 37.7 mg/l vs. 38.2 ± 24.8 mg/l; p < 0.001). Also, there was a negative correlation between ampicillin serum concentrations and GFR (r = -0.659; p < 0.001). CONCLUSION: The described dosing regimen for ampicillin/sulbactam is safe with respect to the defined MIC breakpoints for ampicillin, and continuous subtherapeutic concentration is unlikely. However, with impaired renal function drug accumulation occurs, and with increased renal clearance, drug levels can be below the 4-fold MIC breakpoint.

Sareomycetes cl. nov.: A new proposal for placement of the resinicolous genus Sarea (Ascomycota, Pezizomycotina).

Resinicolous fungi constitute a heterogeneous assemblage of fungi that live on fresh and solidified plant resins. The genus Sarea includes, according to current knowledge, two species, S. resinae and S. difformis. In contrast to other resinicolous discomycetes, which are placed in genera also including non-resinicolous species, Sarea species only ever fruit on resin. The taxonomic classification of Sarea has proven to be difficult and currently the genus, provisionally and based only on morphological features, has been assigned to the Trapeliales (Lecanoromycetes). In contrast, molecular studies have noted a possible affinity to the Leotiomycetes. Here we review the taxonomic placement of Sarea using sequence data from seven phylogenetically informative DNA regions including ribosomal (ITS, nucSSU, mtSSU, nucLSU) and protein-coding (rpb1, rpb2, mcm7) regions. We combined available and new sequence data with sequences from major Pezizomycotina classes, especially Lecanoromycetes and Leotiomycetes, and assembled three different taxon samplings in order to place the genus Sarea within the Pezizomycotina. Based on our data, none of the applied phylogenetic approaches (Bayesian Inference, Maximum Likelihood and Maximum Parsimony) supported the placement of Sarea in the Trapeliales or any other order in the Lecanoromycetes. A placement of Sarea within the Leotiomycetes is similarly unsupported. Based on our data, Sarea forms an isolated and highly supported phylogenetic lineage within the "Leotiomyceta". From the results of our multilocus phylogenetic analyses we propose here a new class, order, and family, Sareomycetes, Sareales and Sareaceae in the Ascomycota to accommodate the genus Sarea. The genetic variability within the newly proposed class suggests that it is a larger group that requires further infrageneric classification.

Liberal fluid fasting: impact on gastric pH and residual volume in healthy children undergoing general anaesthesia for elective surgery.

BACKGROUND: The paediatric preoperative fasting time of 2 h for clear fluids, as suggested by guidelines, is often exceeded. Shorter preoperative fasting has been proposed to avoid potential outcomes such as dehydration, ketoacidosis, reduced arterial blood pressure, and patient discomfort. The aim of this study was to investigate whether liberal clear fluid intake until premedication significantly reduces actual fasting time and impacts gastric pH and residual volume. METHODS: Children (1-16 yr old, ASA I or II) undergoing elective procedures with general anaesthesia requiring tracheal intubation were randomised for clear fluid intake until premedication with midazolam (liberal) or 2 h fluid fasting (standard). Actual fasting times were recorded. Gastric content was sampled after tracheal intubation with an orogastric tube to determine gastric pH and residual volume. Data are presented as median [interquartile range]. RESULTS: We included 162 children aged 1.1-16 yr; gastric pH was determined in 138 patients. Patients' characteristics were similar in the two groups. The liberal fasting group had significantly shorter fasting times (48 [18.5-77.5] vs 234 [223.5-458.5] min; P<0.001). No significant difference was observed regarding gastric pH (1.6 [1.5-1.8] vs 1.6 [1.4-1.7]; P=0.237) or residual volume (0.38 [0.1-1.1] vs 0.43 [0.13-0.73] ml kg-1; P=0.535). Twelve patients (15%) in the liberal group (median fluid fasting 32 min) vs one patient (1%) had gastric residual volumes >2 ml kg-1 (P=0.001). CONCLUSION: Fluid intake until premedication allows for significantly shorter fasting times. Elevated gastric residual volumes may occur more often in patients with fasting times of 30 min or shorter. CLINICAL TRIAL REGISTRATION: NCT02603094.

Prolactin Is a Strong Candidate for the Regulation of Luteal Steroidogenesis in Vizcachas (Lagostomus maximus).

Prolactin (PRL) is essential for the maintenance of the corpora lutea and the production of progesterone (P4) during gestation of mice and rats, which makes it a key factor for their successful reproduction. Unlike these rodents and the vast majority of mammals, female vizcachas (Lagostomus maximus) have a peculiar reproductive biology characterized by an ovulatory event during pregnancy that generates secondary corpora lutea with a consequent increment of the circulating P4. We found that, although the expression of pituitary PRL increased steadily during pregnancy, its ovarian receptor (PRLR) reached its maximum in midpregnancy and drastically decreased at term pregnancy. The luteinizing hormone receptor (LHR) exhibited a similar profile than PRLR. Maximum P4 and LH blood levels were recorded at midpregnancy as well. Remarkably, the P4-sinthesizing enzyme 3ß-HSD accompanied the expression pattern of PRLR/LHR throughout gestation. Instead, the luteolytic enzyme 20α-HSD showed low expression at early and midpregnancy, but reached its maximum at the end of gestation, when PRLR/LHR/3ß-HSD expressions and circulating P4 were minimal. In conclusion, both the PRLR and LHR expressions in the ovary would define the success of gestation in vizcachas by modulating the levels of 20α-HSD and 3ß-HSD, which ultimately determine the level of serum P4 throughout gestation.

Length-based body weight estimation in paediatric patients: The impact of habitus-A clinical observational trial.

BACKGROUND: Paediatric emergency tapes provide drug dosing based on the patient's estimated body weight. Unfortunately, published data revealed an unsatisfactory accuracy. A newly developed digital algorithm for weight estimation (CLAWAR) allowing a three-staged habitus adaptation (normal, obese, or cachectic; CLAWAR-3) demonstrated a higher accuracy for weight estimation compared to paediatric emergency tapes. However, the incidence of incorrectly evaluated habitus was 27%. A five-staged habitus adaptation with figural images was suggested by Wells et al to improve habitus and weight estimation. Therefore, CLAWAR was modified with five habitus stages including figural images (CLAWAR-5). We hypothized CLAWAR-5 improves the accuracy of weight estimation. METHODS: After obtaining informed written parental consent patients were included in this single centre, prospective clinical observation trial. Body weight estimations by CLAWAR-3 and CLAWAR-5 within ±10% of the actual body weight were compared. Furthermore, the incidence of correct evaluated habitus was calculated. McNemar Tests were used for statistical analysis. Results presented as median (interquartiles), P < .003 considered significant. RESULTS: In total, 312 patients aged 3.3 years (0.7-6.6), with a body length of 95.9 cm (70.0-121.2), weighing 14.8 kg (8.1-22.5), were included. Both CLAWAR-3 and CLAWAR-5 showed equivalent accuracy for weight estimation within the ±10% interval (62.2% vs 60.6%, P = .609). Despite adding figural images, the incidence of correct evaluated habitus with CLAWAR-5 (46.8%) was worse than with CLAWAR-3 (66.7%). CONCLUSION: The five-staged habitus-adapted method could not improve the accuracy of weight estimation. Furthermore, the error rate of habitus classification was not reduced by the implementation of figural images.

Accuracy of near-patient vs. inbuilt spirometry for monitoring tidal volumes in an in-vitro paediatric lung model.

Spirometric monitoring provides precise measurement and delivery of tidal volumes within a narrow range, which is essential for lung-protective strategies that aim to reduce morbidity and mortality in mechanically-ventilated patients. Conventional anaesthesia ventilators include inbuilt spirometry to monitor inspiratory and expiratory tidal volumes. The GE Aisys CS2 anaesthesia ventilator allows additional near-patient spirometry via a sensor interposed between the proximal end of the tracheal tube and the respiratory tubing. Near-patient and inbuilt spirometry of two different GE Aisys CS2 anaesthesia ventilators were compared in an in-vitro study. Assessments were made of accuracy and variability in inspiratory and expiratory tidal volume measurements during ventilation of six simulated paediatric lung models using the ASL 5000 test lung. A total of 9240 breaths were recorded and analysed. Differences between inspiratory tidal volumes measured with near-patient and inbuilt spirometry were most significant in the newborn setting (p < 0.001), and became less significant with increasing age and weight. During expiration, tidal volume measurements with near-patient spirometry were consistently more accurate than with inbuilt spirometry for all lung models (p < 0.001). Overall, the variability in measured tidal volumes decreased with increasing tidal volumes, and was smaller with near-patient than with inbuilt spirometry. The variability in measured tidal volumes was higher during expiration, especially with inbuilt spirometry. In conclusion, the present in-vitro study shows that measurements with near-patient spirometry are more accurate and less variable than with inbuilt spirometry. Differences between measurement methods were most significant in the smallest patients. We therefore recommend near-patient spirometry, especially for neonatal and paediatric patients.

Comparison of a paediatric emergency ruler with a digital algorithm for weight and age estimation.

BACKGROUND: Emergency tapes like the "Paediatric-Emergency-Ruler" (PaedER) provide drug dosing and recommend medical airway equipment based on estimated patient bodyweight and age. Previous studies have revealed unsatisfactory accuracy in bodyweight estimation, due to the tapes' length-based weight categories. Therefore, we developed a digital algorithm allowing continuous length-based estimation of weight and age. The aim of this study was to compare the new algorithm with the PaedER regarding accuracy in estimating bodyweight and recommendation of medical airway equipment. METHODS: Patients with a body length suitable for the PaedER were included in this single centre, prospective clinical observation trial after obtaining informed written parental consent. Bodyweight estimations by the algorithm and PaedER within ± 10% and ± 20% of the actual bodyweight were compared. Furthermore, medical airway equipment suggested by the PaedER and algorithm were compared with the equipment actually used for anaesthesia. Wilcoxon- and McNemar-Tests were used for statistical analysis. Results are median (interquartiles), P < 0.05 was considered significant. RESULTS: In total, 489 patients aged 2.0 years (0.4-5.9), with a body length of 89.0 cm (63.5-114.5), weighing 12.8 kg (6.3-19.6), were included. The algorithm's precision of bodyweight estimation within ± 10%/± 20% was significantly higher at 64.0%/91.6% than the PaedER at 55.4%/81.8% (P < 0.001). Compared to PaedER the algorithm showed a higher incidence of correctly recommended medical airway equipment based on its accuracy for age and bodyweight estimation. CONCLUSION: The new digital algorithm is an alternative to conventional emergency tapes, showing improved accuracy regarding length-based estimation of bodyweight and recommendation of medical airway equipment.

Intraoperative music application in children and adolescents - a pilot study.

BACKGROUND: Hospitalization, surgery and anaesthesia may lead to new-onset maladaptive behaviour, emotional distress and trauma. This pilot study aims to investigate the influence of intraoperatively applied music on post-operative behaviour in children and adolescents. METHODS: Children with an ASA physical state classification of I or II, aged from 4 to 16 years and scheduled for elective circumcision or inguinal hernia repair under combined general and caudal anaesthesia were included. The children were randomized into two groups. They wore headphones during surgery, and were either exposed to music or not. All involved staff were blinded. Post-operative behaviour was documented by parents on day 7, 14 and 28 after surgery, using a questionnaire adapted from the "Post Hospitalization Behavioural Questionnaire" (PHBQ). Overall occurrence of at least one item indicating maladaptive behaviour was the primary outcome. Data are presented as median (interquartile range). RESULTS: In total, 135 children aged 6.6 (5.3-8.5) years, weighing 22 (19-29) kg, were included, with 112 completed questionnaires returned. Overall occurrence of at least one maladaptive item was lower in the music group, with a significantly lower incidence on day 7 (51% vs. 77% in controls; P < 0.01). CONCLUSION: Intraoperative music application in children undergoing minor surgical procedures may reduce the incidence of post-operative maladaptive behaviour within the first week.

Performance of adjustable pressure-limiting (APL) valves in two different modern anaesthesia machines.

The ability to gently ventilate a patient's lungs using a self-inflating bag requires a properly working adjustable pressure-limiting (APL) valve. We compared the performance of the APL valves of the GE Aisys CS2 and the Draeger Fabius anaesthetic machines during closure and opening from 1-20 and from 20-1 cmH2 O, using standardised experimental baby and adolescent patient lung models. Airway pressures and inspiratory tidal volumes were measured using an ASL-5000 test lung and a GE Aisys CS2 near-patient spirometry sensors. In both lung models, the GE Aisys CS2 APL valves demonstrated non-linear behaviours for airway pressures and for inspiratory tidal volumes, with a sharp increase at set APL pressure levels of 8-10 cmH2 O. With further closure of the GE Aisys CS2 APL valves up to 20 cmH2 O, inspiratory tidal volumes decreased to ~50% of the highest values measured. Airway pressures in the Draeger Fabius APL valves demonstrated a near linear increase and decrease. Airway pressure values measured in the Draeger Fabius were never higher than those set by the APL valves, whereas in the GE Aisys CS2 , they considerably exceeded set pressures (by up to 27 cmH2 O). We conclude that the performance of the GE Aisys CS2 APL valve does not allow safe bag-assisted ventilation of a patient's lungs.

[Monitoring tidal volumes when using the Ventrain® emergency ventilator]. / Monitoring der Tidalvolumina bei Verwendung des Ventrain® Notfallbeatmungsgerätes.

BACKGROUND: The Ventrain® emergency ventilation device allows active inspiration and expiration through transtracheal catheters or the lumen of an airway exchange catheter. This single-use handheld device is manually operated and driven by an external pressurized oxygen source. The Ventrain® may be used to ventilate patients with a complete or pending upper airway obstruction reducing the risk of barotrauma due to the possibility of active expiration. However tidal volumes (V T) applied and withdrawn with the Ventrain® can only be controlled by visual inspection of chest movements; V T monitoring is not provided. Excessive inspiratory volumes or air trapping due to insufficient expiration may remain clinically undetected until pulmonary trauma and/or cardio-respiratory deterioration occur. Active expiration itself carries the risk of overwhelming lung deflation with the formation of atelectasis. Thus, an inspiratory and expiratory tidal volume monitor is urgently required. The aim of this study was to evaluate efficacy and precision of the Florian respiratory function monitor (RFM) to monitor in- and expiratory V T administered by the Ventrain® emergency ventilation device through a small cannula to the ASL 5000 test lung (ASL). METHODS: In an in-vitro setting the RFM was used with its neonatal flow sensor to monitor inspiratory and expiratory V T applied by the Ventrain® emergency ventilation device through a 2 mm internal diameter (ID) transtracheal catheter to the ASL. Driving flows of 6, 9, 12 and 15 l min(-1) were chosen to vary tidal volumes at a constant respiratory rate of 15 min(-1) and an I:E ratio of 1:1. Experiments were repeated five times with two flow sensors. An initial set-up calibration run was performed to calculate a bias correction factor for inspiratory and expiratory V T measured by the RFM. This bias correction factor was used to simulate a correction of the in the RFM programmed linearization table. In a second, identical setting the experiments were repeated five times with two flow sensors. V T measured by the adjusted RFM were compared with those obtained from the ASL 5000 in this second run and the percentage differences were calculated. Bland Altman analysis was used to investigate the agreement of inspiratory or expiratory VT measured by both methods (ASL and RFM). Calculation of the mean of differences between both methods is given as bias and the 95 % agreement interval as precision. RESULTS: Tidal volumes measured by the ASL ranged from 140 to 675 ml. The percentage correction factor was 16.27 % (2.60 %) during inspiration for V T ranged from 0 to 700 ml and 11.51 % (2.56 %) during expiration for V T of 0 to 225 ml, 7.41 % (2.94 %) for VT 226 to 325 ml and 5.35 % (3.57 %) for TV e > 325 ml. Inspiratory and expiratory tidal volumes measured by the adjusted RFM demonstrated a percentage deviation (mean [SD]) of 2.59 % (1.86 %) during inspiration and 1.66 % (1.14 %) during expiration when compared with the ASL 5000. Bias (precision) of the Bland Altman plot for the adjusted RFM is 2.05 ml (23.20) during inspiration and 4.62 ml (10.40) for expiration. CONCLUSION: The tested respiratory function monitor using hot-wire anemometer technology has the potential to monitor tidal volumes applied by the Ventrain®. With the software thus adapted, the RFM measures precise inspiratory and expiratory tidal volumes within common technical tolerance. This could help perform adequate patient ventilation with Ventrain® and reduce the potential risk of patient trauma.

Microbe-like inclusions in tree resins and implications for the fossil record of protists in amber.

During the past two decades, a plethora of fossil micro-organisms have been described from various Triassic to Miocene ambers. However, in addition to entrapped microbes, ambers commonly contain microscopic inclusions that sometimes resemble amoebae, ciliates, microfungi, and unicellular algae in size and shape, but do not provide further diagnostic features thereof. For a better assessment of the actual fossil record of unicellular eukaryotes in amber, we studied equivalent inclusions in modern resin of the Araucariaceae; this conifer family comprises important amber-producers in Earth history. Using time-of-flight secondary ion mass spectrometry (ToF-SIMS), we investigated the chemical nature of the inclusion matter and the resin matrix. Whereas the matrix, as expected, showed a more hydrocarbon/aromatic-dominated composition, the inclusions contain abundant salt ions and polar organics. However, the absence of signals characteristic for cellular biomass, namely distinctive proteinaceous amino acids and lipid moieties, indicates that the inclusions do not contain microbial cellular matter but salts and hydrophilic organic substances that probably derived from the plant itself. Rather than representing protists or their remains, these microbe-like inclusions, for which we propose the term 'pseudoinclusions', consist of compounds that are immiscible with the terpenoid resin matrix and were probably secreted in small amounts together with the actual resin by the plant tissue. Consequently, reports of protists from amber that are only based on the similarity of the overall shape and size to extant taxa, but do not provide relevant features at light-microscopical and ultrastructural level, cannot be accepted as unambiguous fossil evidence for these particular groups.

Impact of oxygen sources on performance of the Ventrain(®) ventilation device in an in vitro set-up.

BACKGROUND: The Ventrain(®) (Dolphys Medical, Eindhoven, The Netherlands) is a disposable handheld ventilation device allowing active inspiration and expiration through a transtracheal catheter. This study investigated Ventrain(®) 's performance when used with different clinical oxygen sources in an in vitro set-up. METHODS: Three anesthesia oxygen sources (wall-mounted flowmeter, respirator oxygen outlet port, and anesthesia ventilator circuit) were used at gas flow rates of 6, 9, 12, and 15 l/min. First, the sources' driving pressures (DP), the insufflation pressure (IP), and the flow at the catheter tip were measured using a gas flow analyzer. Tidal volumes (VT) delivered by the Ventrain(®) were assessed by the ASL5000 test lung (respiratory rate: 15 min(-1), I:E = 1:1, compliance: 100 ml/cmH2O, resistance: 3.06 cmH2O/l/s). RESULTS: VT ranged from 82 to 483 ml for inspiration and 82 to 419 ml for expiration. Measured IP, flow, and VT were less dependent on the set gas flow rate but more on the source's DP. With rising DP the IP, the flow at the catheter tip and consequently VT increased. At an approximate target I:E ratio of 1:1, the ratio of inspiratory to expiratory VT increased with higher DP and gas flow rates. CONCLUSION: The oxygen sources resulted in clinically different IP, flows, and VT delivered by the Ventrain(®) at given gas flow rates. This needs to be considered in a clinical emergency situation. Integrating an adjustable pressure valve into Ventrain(®) to allow regulation of the lowest necessary IP would make its use safer.

[Comparison of five video laryngoscopes and conventional direct laryngoscopy : Investigations on simple and simulated difficult airways on the intubation trainer]. / Vergleich von fünf Videolaryngoskopen und direkter konventioneller Laryngoskopie : Untersuchung des einfachen und simulierten schwierigen Atemweg am Intubationstrainer.

INTRODUCTION: Securing the airway with a tracheal tube is essential in emergency situations, in the intensive care setting as well as during anesthesia for surgery and other interventions. Current methods of airway assessment are poor screening tests for predicting difficult direct laryngoscopy due to a generally low positive predictive value; therefore, successful endotracheal intubation requires a high level of expertise, regular training and practice and sometimes additional tools. Currently, several video laryngoscopes (VL) with different designs are commercially available and have been investigated in a wide variety of settings. To our knowledge there is no prospective study evaluating and comparing performance among these three groups of VL; therefore, the aim of this study was to compare performance of five VL and conventional direct laryngoscopy in an intubation manikin model, both in a normal and simulated difficult intubation setting. METHODS: In this study 10 residents, 12 senior staff physicians and 5 anesthesia nurses, all experienced in conventional direct laryngoscopy and inexperienced with VL underwent theoretical and hands-on training with all VL lasting 60 min. Afterwards participants performed intubation with all 5 VL and conventional direct laryngoscopy in a randomized sequence using an intubation manikin with normal intubation settings. Thereafter participants performed intubation in a simulated difficult intubation setting using the same intubation manikin with a neck collar to immobilize the cervical spine. In this study, the C-MAC(®) with Macintosh blade size 3, GlideScope(®) size 3, McGrath(®) series 5, King Vision(®) and Airtraq(®) size 2 were used. Time to intubation served as primary outcome and time to glottis visualization, number of intubation attempts, success rate and subjective evaluation of difficulty served as secondary outcomes. RESULTS: In the normal intubation setting, time to intubation ranged from 16.0 s (conventional direct laryngoscopy) to 34.3 s (McGrath). GlideScope and conventional direct laryngoscopy were successful in 100 % followed by C-MAC (96.7 %), Airtraq (88.9 %), King Vision (77.8 %) and McGrath VL (44.4 %). In the simulated difficult intubation setting, time to intubation ranged between 20.3 s (Airtraq) and 26.7 s (McGrath). Success rate with C-MAC was 100 %, followed by GlideScope (96.7 %), Airtraq (85.2 %), conventional direct laryngoscopy (85.2 %), King Vision (81.5 %) and McGrath VL (70.4 %). CONCLUSION: In the manikin with normal intubation setting, conventional direct laryngoscopy using a Macintosh blade was convincing and superior to any VL used in this study. During simulated difficult intubation, a blade with video transmission, such as C-MAC and the GlideScope were superior compared to conventional direct laryngoscopy and any other VL tested.

Gastric pH and residual volume after 1 and 2 h fasting time for clear fluids in children†.

INTRODUCTION: Current guidelines suggest a fasting time of 2 h for clear fluids, which is often exceeded in clinical practice, leading to discomfort, dehydration and stressful anaesthesia induction to patients, especially in the paediatric population. Shorter fluid fasting might be a strategy to improve patient comfort but has not been investigated yet. This prospective clinical trial compares gastric pH and residual volume after 1 vs 2 h of preoperative clear fluid fasting. METHODS: Children (1-16 yr, ASA I or II) undergoing elective procedures in general anaesthesia requiring tracheal intubation were randomized into group A with 60 min or B with 120 min preoperative clear fluid fasting. To determine gastric pH and residual volume, the gastric content was sampled in supine, left and right lateral patient position using an oro-gastric tube after intubation. Data are median (interquartile range) for group A or B (P<0.05). RESULTS: In total, 131 children aged 1.01-16.23 yr were included; gastric pH was determined in 120 cases. Patient characteristic data were similar between the two groups, except for gender (46/33 males in group A/B; P=0.02). Despite significantly shorter fasting times for clear fluids in group A compared with group B (76/136 min; P<0.001), no significant difference was observed regarding gastric pH [1.43 (1.30-1.56)/1.44 (1.29-1.68), P=0.66] or residual volume [0.43 (0.21-0.84)/0.46 (0.19-0.78) ml kg(-1), P=0.47]. CONCLUSION: One hour clear fluid fasting does not alter gastric pH or residual volume significantly compared with 2 h fasting. CLINICAL TRIAL REGISTRATION: The study was approved by the local ethics committee (KEK-ZH-Nr. 2011-0034) and registered with ClinicalTrials.gov (NCT01516775).

Nasotracheal intubation depth in paediatric patients.

BACKGROUND: The aim of this study was to compare intubation depth using the Microcuff paediatric endotracheal tube (PET) placed with the intubation depth mark between the vocal cords with that of different published formulae/recommendations for nasotracheal intubation depth in children. METHODS: Children aged from birth to 10 yr undergoing elective surgery with nasotracheal intubation were included. Tracheal tubes were adjusted according to the intubation depth mark between the vocal cords using direct laryngoscopy. Nasal intubation depth was recorded and the distance 'tube tip to carina' was measured endoscopically. Based on the recorded nasal intubation depth and measured distance 'tube tip to carina', the position of tube tip and cuff was calculated according to six published formulae/recommendations. RESULTS: Seventy-six children were studied. For the Microcuff PET, the median tube tip advancement within the trachea was 52.9% (41.1-73.8%) of tracheal length. The shortest distance from the 'tube tip to carina' was 15 mm for a 3.5 mm internal diameter tube. If the six published formulae/recommendations had been used, this would have resulted in endobronchial tube placement in up to 9.1% of cases, and the tube tip would have been placed above the glottis in up to 2.6% of cases. The upper border of the cuff would have been placed in the subglottic area in up to 42.1% of cases and in a supraglottic position in up to 63.2% of cases. CONCLUSIONS: This study indicates that nasal intubation with the intubation depth mark placed between the vocal cords was superior to formula-based nasotracheal tube positioning. The latter would result in a high rate of endobronchial intubations, excessively high cuff positions and even tracheal extubations.

Intra-unit-cell electronic nematicity of the high-T(c) copper-oxide pseudogap states.

In the high-transition-temperature (high-T(c)) superconductors the pseudogap phase becomes predominant when the density of doped holes is reduced. Within this phase it has been unclear which electronic symmetries (if any) are broken, what the identity of any associated order parameter might be, and which microscopic electronic degrees of freedom are active. Here we report the determination of a quantitative order parameter representing intra-unit-cell nematicity: the breaking of rotational symmetry by the electronic structure within each CuO(2) unit cell. We analyse spectroscopic-imaging scanning tunnelling microscope images of the intra-unit-cell states in underdoped Bi(2)Sr(2)CaCu(2)O(8 +) (delta) and, using two independent evaluation techniques, find evidence for electronic nematicity of the states close to the pseudogap energy. Moreover, we demonstrate directly that these phenomena arise from electronic differences at the two oxygen sites within each unit cell. If the characteristics of the pseudogap seen here and by other techniques all have the same microscopic origin, this phase involves weak magnetic states at the O sites that break 90 degrees -rotational symmetry within every CuO(2) unit cell.

Imaging the Fano lattice to 'hidden order' transition in URu(2)Si(2).

Within a Kondo lattice, the strong hybridization between electrons localized in real space (r-space) and those delocalized in momentum-space (k-space) generates exotic electronic states called 'heavy fermions'. In URu(2)Si(2) these effects begin at temperatures around 55 K but they are suddenly altered by an unidentified electronic phase transition at T(o) = 17.5 K. Whether this is conventional ordering of the k-space states, or a change in the hybridization of the r-space states at each U atom, is unknown. Here we use spectroscopic imaging scanning tunnelling microscopy (SI-STM) to image the evolution of URu(2)Si(2) electronic structure simultaneously in r-space and k-space. Above T(o), the 'Fano lattice' electronic structure predicted for Kondo screening of a magnetic lattice is revealed. Below T(o), a partial energy gap without any associated density-wave signatures emerges from this Fano lattice. Heavy-quasiparticle interference imaging within this gap reveals its cause as the rapid splitting below T(o) of a light k-space band into two new heavy fermion bands. Thus, the URu(2)Si(2) 'hidden order' state emerges directly from the Fano lattice electronic structure and exhibits characteristics, not of a conventional density wave, but of sudden alterations in both the hybridization at each U atom and the associated heavy fermion states.

Spectroscopic fingerprint of phase-incoherent superconductivity in the cuprate pseudogap state [corrected].

A possible explanation for the existence of the cuprate "pseudogap" state is that it is a d-wave superconductor without quantum phase rigidity. Transport and thermodynamic studies provide compelling evidence that supports this proposal, but few spectroscopic explorations of it have been made. One spectroscopic signature of d-wave superconductivity is the particle-hole symmetric "octet" of dispersive Bogoliubov quasiparticle interference modulations. Here we report on this octet's evolution from low temperatures to well into the underdoped pseudogap regime. No pronounced changes occur in the octet phenomenology at the superconductor's critical temperature Tc, and it survives up to at least temperature T approximately 1.5 Tc. In this pseudogap regime, we observe the detailed phenomenology that was theoretically predicted for quasiparticle interference in a phase-incoherent d-wave superconductor. Thus, our results not only provide spectroscopic evidence to confirm and extend the transport and thermodynamics studies, but they also open the way for spectroscopic explorations of phase fluctuation rates, their effects on the Fermi arc, and the fundamental source of the phase fluctuations that suppress superconductivity in underdoped cuprates.