Explore the vast range of titles available.

Dynamic parameters of preload have been widely recommended to guide fluid therapy based on the principle of fluid responsiveness and with regard to cardiac output. An equally important aspect is however to also avoid volume-overload. This accounts particularly when capillary leakage is present and volume-overload will promote impairment of microcirculatory blood flow. The aim of this study was to evaluate, whether an impairment of intestinal microcirculation caused by volume-load potentially can be predicted using pulse pressure variation in an experimental model of ischemia/reperfusion injury. The study was designed as a prospective explorative large animal pilot study. The study was performed in 8 anesthetized domestic pigs (German landrace). Ischemia/reperfusion was induced during aortic surgery. 6 h after ischemia/reperfusion-injury measurements were performed during 4 consecutive volume-loading-steps, each consisting of 6 ml kg −1 bodyweight −1 . Mean microcirculatory blood flow (mean Flux) of the ileum was measured using direct laser-speckle-contrast-imaging. Receiver operating characteristic analysis was performed to determine the ability of pulse pressure variation to predict a decrease in microcirculation. A reduction of ≥ 10% mean Flux was considered a relevant decrease. After ischemia–reperfusion, volume-loading-steps led to a significant increase of cardiac output as well as mean arterial pressure, while pulse pressure variation and mean Flux were significantly reduced (Pairwise comparison ischemia/reperfusion-injury vs. volume loading step no. 4): cardiac output (l min −1 ) 1.68 (1.02–2.35) versus 2.84 (2.15–3.53), p  = 0.002, mean arterial pressure (mmHg) 29.89 (21.65–38.12) versus 52.34 (43.55–61.14), p  < 0.001, pulse pressure variation (%) 24.84 (17.45–32.22) versus 9.59 (1.68–17.49), p  = 0.004, mean Flux (p.u.) 414.95 (295.18–534.72) versus 327.21 (206.95–447.48), p  = 0.006. Receiver operating characteristic analysis revealed an area under the curve of 0.88 (CI 95% 0.73–1.00; p value < 0.001) for pulse pressure variation for predicting a decrease of microcirculatory blood flow. The results of our study show that pulse pressure variation does have the potential to predict decreases of intestinal microcirculatory blood flow due to volume-load after ischemia/reperfusion-injury. This should encourage further translational research and might help to prevent microcirculatory impairment due to excessive fluid resuscitation and to guide fluid therapy in the future.

PurposePostoperative complications after major liver surgery are common. Thoracic epidural anesthesia may provide beneficial effects on postoperative outcome. We strove to compare postoperative outcomes in major liver surgery patients with and without thoracic epidural anesthesia.MethodsThis was a retrospective cohort study in a single university medical center. Patients undergoing elective major liver surgery between April 2012 and December 2016 were eligible for inclusion. We divided patients into two groups according to whether or not they had thoracic epidural anesthesia for major liver surgery. The primary outcome was postoperative hospital length of stay, i.e., from day of surgery until hospital discharge. Secondary outcomes included 30-day postoperative mortality and major postoperative complications. Additionally, we investigated the effect of thoracic epidural anesthesia on perioperative analgesia doses and the safety of thoracic epidural anesthesia.ResultsOf 328 patients included in this study, 177 (54.3%) received thoracic epidural anesthesia. There were no clinically important differences in postoperative hospital length of stay (11.0 [7.00–17.0] vs. 9.00 [7.00–14.0] days, p = 0.316, primary outcome), death (0.0 vs. 2.7%, p = 0.995), or the incidence of postoperative renal failure (0.6 vs. 0.0%, p = 0.99), sepsis (0.0 vs. 1.3%, p = 0.21), or pulmonary embolism (0.6 vs. 1.4%, p = 0.59) between patients with or without thoracic epidural anesthesia. Perioperative analgesia doses — including the intraoperative sufentanil dose (0.228 [0.170–0.332] vs. 0.405 [0.315–0.565] μg·kg−1·h−1, p < 0.0001) — were lower in patients with thoracic epidural anesthesia. No major thoracic epidural anesthesia-associated infections or bleedings occurred.ConclusionThis retrospective analysis suggests that thoracic epidural anesthesia does not reduce postoperative hospital length of stay in patients undergoing major liver surgery — but it may reduce perioperative analgesia doses. Thoracic epidural anesthesia was safe in this cohort of patients undergoing major liver surgery. These findings need to be confirmed in robust clinical trials.

Preoxygenation is a crucial manoeuvre for patients’ safety, particularly for morbidly obese patients due to their reduced pulmonary reserve and increased risk for difficult airway situations. The oxygen reserve index (ORI™) was recently introduced as a new parameter of multiple wavelength pulse oximetry and has been advocated to allow assessment of hyperoxia [quantified by the resulting arterial oxygen partial pressure ( P aO 2 )]. This study investigates if ORI can be used to evaluate the impact of two different preoxygenation manoeuvres on the grade of hyperoxia. Two preoxygenation manoeuvres were sequentially evaluated in 41 morbidly obese patients: First, breathing 100% oxygen for 5 min via standard face mask. Second, after achieving a second baseline, 5 min of non-invasive ventilation (NIV) with 100% oxygen. The effect of preoxygenation on ORI compared to P aO 2 was evaluated and whether differences in the two preoxygenation manoeuvres can be monitored by ORI. Overall correlation of P aO 2 and ORI was significant (Spearman-Rho coefficient of correlation 0.818, p < 0.001). However, ORI could not differentiate between the two preoxygenation manoeuvres although the P aO 2 values for NIV preoxygenation were significantly higher compared to standard preoxygenation (median 505 mmHg (M1) vs. 550 mmHg (M3); p < 0.0001). In contrast, ORI values did not differ significantly (median 0.39 (M1) vs. 0.38 (M3); p = 0.758). Absolute values of ORI cannot be used to assess effectiveness of a preoxygenation procedure in bariatric patients, mainly because its range of discrimination is considerably lower than the high ranges of P aO 2 attained by adequate preoxygenation. Trial registration German Clinical Trials Register: DRKS00025023 (retrospectively registered on April 16th, 2021).

The aim of this study was to evaluate the accuracy and precision of non-invasive continuous blood pressure measurement by applanation tonometry (AT) in awake or anaesthetised cardiological intensive care patients. Patients suffering from highly impaired left ventricular function atrial fibrillation or severe aortic valve stenosis were included into the study. Arterial blood pressure was recorded by applanation tonometry (T-Line 400, Tensys Medical®, USA) and an arterial line in awake or anaesthetised patients. Discrepancies in mean (MAP), systolic (SAP), and diastolic (DAP) arterial pressure between the two methods were assessed as bias, limits of agreement and percentage error respectively. In 31 patients a total of 27,900 measurements were analyzed. The concordance correlation coefficient was 0.23, 0.45 and 0.06 for MAP, SAP and DAP, respectively. For all patients bias for MAPAT compared to MAPAL was 14.96 mmHg (SAPAT 4.51 mmHg; DAPAT 19.12 mmHg) with limits of agreement for MAPAT of 46.25 and − 16.33 mm Hg (SAPAT 48.00 and − 38.98 mmHg; DAPAT 50.12 and − 11.89 mmHg). Percentage error for MAPAT was 56.8% (42.7% for SAPAT; 75.2% for DAPAT). We conclude that the AT method is not reliable in ICU patients with severe cardiac comorbidities.

Phenylephrine is an α1-adrenergic receptor agonist widely used to treat perioperative hypotension. Its other hemodynamic effects, in particular on preload and contractility, remain controversial. We, therefore, investigated the effect of continuously applied phenylephrine on central hemodynamics in eight mechanically ventilated domestic pigs. Mean arterial pressure (MAP) was increased in steps by 50%, and 100% using phenylephrine. Besides stroke volume (SV), cardiac output (CO), and MAP, mean systemic vascular resistance (SVR) and dynamic arterial elastance (Eadyn) were assessed for characterization of afterload. Changes in preload were assessed by central venous pressure (CVP), global end-diastolic volume (GEDV), mean systemic filling pressure analog (Pmsfa), pulse pressure variation (PPV), and stroke volume variation (SVV). Further, cardiac function index (CFI), global ejection fraction and dPmax were measured as markers of preload dependent contractility. MAP, SV, and CO significantly increased following both interventions, as did SVR. In contrast, Eadyn did not show significant changes. Although the volumetric preload variable GEDV increased after the first step of phenylephrine, this was not reflected by significant changes in CVP or Pmsfa. CFI and dPmax significantly increased after both steps. Phenylephrine does not only affect cardiac afterload, but also increases effective preload. In contrast to CVP and Pmsfa, this effect can be monitored by GEDV. Further, phenylephrine affects contractility.

Purpose In order to assess the occurrence of blood congestion in the liver during liver resection, we aimed to evaluate the influence of a positive-end-expiratory-pressure (PEEP) and positioning of patients on central venous pressure (CVP) and venous hepatic blood flow parameters. We further analyzed correlations between CVP and venous hepatic blood flow parameters. Methods In 20 patients scheduled for elective liver resection we measured CVP and quantified venous hepatic hemodynamics by ultrasound assessment of flow-velocity and diameter of the right hepatic vein and the portal vein after equilibration following these maneuvers: M1: 0° supine position, PEEP 0 cmH 2 O; M2: 0° supine position, PEEP 10 cmH 2 O; M3: 20° reverse-trendelenburg position; PEEP 10 cmH 2 O; M4: 20° reverse-trendelenburg position, PEEP 0cmH 2 O. Results Changing from supine to reverse-trendelenburg position led to a significant decrease in CVP (M3 5.95 ± 2.06 vs. M1 7.35 ± 2.18 mmHg and M2 8.55 ± 1.79 mmHg). A PEEP of 10 cmH 2 O and reverse-trendelenburg position led to significant reduction of systolic (Vs HV ) and diastolic (Vd HV ) flow-velocities of the right hepatic vein (Vs HV M3 19.96 ± 6.47 vs. M1 27.81 ± 11.03 cm s −1 ;Vd HV M3 14.94 ± 6.22 vs. M1 20.15 ± 10.34 cm s −1 and M2 20.19 ± 13.19 cm s −1 ) whereas no significant changes of flow-velocity occurred in the portal vein. No correlations between CVP and diameters or flow-velocities of the right hepatic and the portal vein were found. Conclusions Changes of central venous pressure due to changes of PEEP and positioning were not correlated with changes of venous hepatic blood flow parameters as measured after equilibration. Strategies aiming for low central venous pressure cannot be supported by these results. However, before ruling out low-CVP-strategies during liver resections these results should be confirmed by further studies.

This work aims at constraining the size, shape, and geometric albedo of the dwarf planet candidate 2002 MS4 through the analysis of nine stellar occultation events. Using multichord detection, we also studied the object's topography by analyzing the obtained limb and the residuals between observed chords and the best-fitted ellipse. We predicted and organized the observational campaigns of nine stellar occultations by 2002 MS4 between 2019 and 2022, resulting in two single-chord events, four double-chord detections, and three events with three to up to sixty-one positive chords. Using 13 selected chords from the 8 August 2020 event, we determined the global elliptical limb of 2002 MS4. The best-fitted ellipse, combined with the object's rotational information from the literature, constrains the object's size, shape, and albedo. Additionally, we developed a new method to characterize topography features on the object's limb. The global limb has a semi-major axis of 412 \\(\\pm\\) 10 km, a semi-minor axis of 385 \\(\\pm\\) 17 km, and the position angle of the minor axis is 121 \\(^\\circ\\) \\(\\pm\\) 16\\(^\\circ\\). From this instantaneous limb, we obtained 2002 MS4's geometric albedo and the projected area-equivalent diameter. Significant deviations from the fitted ellipse in the northernmost limb are detected from multiple sites highlighting three distinct topographic features: one 11 km depth depression followed by a 25\\(^{+4}_{-5}\\) km height elevation next to a crater-like depression with an extension of 322 \\(\\pm\\) 39 km and 45.1 \\(\\pm\\) 1.5 km deep. Our results present an object that is \\(\\approx\\)138 km smaller in diameter than derived from thermal data, possibly indicating the presence of a so-far unknown satellite. However, within the error bars, the geometric albedo in the V-band agrees with the results published in the literature, even with the radiometric-derived albedo.