The Value of Next-Generation Sequencing in Diagnosis and Therapy of Critically Ill Patients with Suspected Bloodstream Infections: A Retrospective Cohort Study.

Bloodstream infection (BSI), a frequent cause of severe sepsis, is a life-threatening complication in critically ill patients and still associated with a high mortality rate. Rapid pathogen identification from blood is crucial for an early diagnosis and the treatment of patients with suspected BSI. For this purpose, novel diagnostic tools on the base of genetic analysis have emerged for clinical application. The aim of this study was to assess the diagnostic value of additional next-generation sequencing (NGS) pathogen test for patients with suspected BSI in a surgical ICU and its potential impact on antimicrobial therapy. In this retrospective single-centre study, clinical data and results from blood culture (BC) and NGS pathogen diagnostics were analysed for ICU patients with suspected BSI. Consecutive changes in antimicrobial therapy and diagnostic procedures were evaluated. Results: 41 cases with simultaneous NGS and BC sampling were assessed. NGS showed a statistically non-significant higher positivity rate than BC (NGS: 58.5% (24/41 samples) vs. BC: 21.9% (9/41); p = 0.056). NGS detected eight different potentially relevant bacterial species, one fungus and six different viruses, whereas BC detected four different bacterial species and one fungus. NGS results affected antimicrobial treatment in 7.3% of cases. Conclusions: NGS-based diagnostics have the potential to offer a higher positivity rate than conventional culture-based methods in patients with suspected BSI. Regarding the high cost, their impact on anti-infective therapy is currently limited. Larger randomized prospective clinical multicentre studies are required to assess the clinical benefit of this novel diagnostic technology.

Evaluation of Intraoperative Left-Ventricular Diastolic Function by Myocardial Strain in On-Pump Coronary Artery Bypass Surgery.

OBJECTIVES: Left ventricular (LV) diastolic function strongly predicts outcomes after cardiac surgery, but there is no consensus about appropriate intraoperative assessment. Recently, intraoperative diastolic strain-based measurements assessed by transesophageal echocardiography (TEE) have shown a strong correlation with LV relaxation, compliance, and filling, but there are no reports about evaluation through the entire perioperative period. Therefore, the authors describe the intraoperative course of this novel assessment technique in patients who underwent coronary artery bypass grafting, and compare it with conventional echocardiographic measures and common grading algorithms of LV diastolic dysfunction (LVDD). DESIGN: Prospectively obtained data. SETTING: A single university hospital. PARTICIPANTS: Thirty adult patients scheduled for isolated on-pump coronary artery bypass grafting surgery with preoperative preserved left and right ventricular systolic function, without significant heart valve disease and pulmonary hypertension, and an uneventful intraoperative course were included. INTERVENTIONS: Transesophageal echocardiography was performed after induction of anesthesia (T1), after termination of cardiopulmonary bypass (T2), and after sternal closure (T3). Echocardiographic evaluation was performed in stable hemodynamic conditions, in sinus rhythm or atrial pacing, and vasopressor support with norepinephrine ≤0.1 µg/kg/min. MEASUREMENTS AND MAIN RESULTS: Strain-based measurements of peak longitudinal strain rate during isovolumetric relaxation (SR-IVR) and during early (SR-E) and late (SR-A) LV filling were assessed using EchoPAC v204 software (GE Vingmed Ultrasound AS, Norway). Evaluation of conventional echocardiographic parameters included transmitral Doppler measures of early (E) and late (A) LV filling, as well as lateral-tissue Doppler velocity assessed during early (e´) and late (a´) LV filling, tricuspid regurgitation, and left atrial dilatation. Evaluation and grading of LV diastolic function by myocardial strain was feasible in all included patients at all time points of assessment. Using conventional grading algorithms, however, a substantial number of patients could not be sufficiently graded, falling into an indeterminate zone and not reliably estimating LVDD (T1, 40%; T2, 33%; T3, 36%). There was significant impairment of LV diastolic function after bypass, as measured by SR-IVR (T1 v T2, 0.28 s-1 [IQR 0.23; 0.31) v 0.18 s-1 [IQR 0.14; 0.22]; p < 0.001), SR-E (T1 v T2, 0.95 ± 0.34 s-1v 1.28 ± 0.36 s-1; p < 0.001), and E/SR-IVR (T1 v T2, 2.3 ± 1.0 m v 4.5 ± 2.1 m; p < 0.001]. Conventional echocardiographic measures remained unchanged during the same period (E/A T1 v T2, 1.27 [IQR 0.94; 1.59] v 1.21 [IQR 1.03; 1.47] [p = 1] and E/e´ T1 v T2, 7.0 [IQR 5.3; 9.6] v 6.35 [IQR 5.7; 9.9] [p = 0.9]). There were no significant changes in the values of SR-IVR, SR-E, SR-A, E/SR-IVR, E/A, and E/e´ before and after sternal closure (T2 v T3). CONCLUSION: Intraoperative assessment of strain-based measurements of LV diastolic function and strain-based LVDD grading was feasible in this group of selected patients, whereas conventional parameters failed to describe LVDD sufficiently in a substantial number of patients. Diastolic strain-based measurements showed impairment of LV relaxation and compliance after bypass, which was not detected by conventional echocardiographic parameters. Therefore, diastolic myocardial strain analysis might be more sensitive in detecting myocardial diastolic dysfunction by TEE in the perioperative setting, with its dynamic changes of loading conditions, and might provide valuable and additional information on the perioperative changes of LV diastolic function.

Intraoperative Augmented Rotation and Circumferential Strain Compensate for Reduction of Left Ventricular Longitudinal Function After On-Pump CABG Surgery.

OBJECTIVES: Left ventricular (LV) longitudinal function is reduced after on-pump coronary artery bypass grafting (CABG), while global LV function often is preserved. There are only limited data on the underlying compensatory mechanism. Therefore, the authors aimed to describe intraoperative changes of LV contractile pattern by myocardial strain analysis. DESIGN: A prospective observational study. SETTING: At a single university hospital. PARTICIPANTS: A total of 30 patients scheduled for isolated on-pump CABG with an uneventful intraoperative course and preoperative preserved LV and RV function, sinus rhythm, without more-than-mild heart valve disease, or elevated pulmonary pressure. INTERVENTIONS: Transesophageal echocardiography was performed after induction of anesthesia (T1), after termination of cardiopulmonary bypass (T2), and after sternal closure (T3). Echocardiographic evaluation was performed under stable hemodynamics, in sinus rhythm or atrial pacing, and vasopressor support with norepinephrine ≤0.1 µg/kg/min. MEASUREMENTS AND MAIN RESULTS: EchoPAC v204 software (GE Vingmed Ultrasound AS, Norway) was used for analysis of 2-dimensional (2D) and 3-dimensional (3D) LV ejection fraction (EF), LV global longitudinal strain (GLS), LV global circumferential strain (GCS), LV global radial strain (GRS), LV apical rotation (aRot), LV basal rotation (bRot), and LV twist. Strain analysis was feasible in all included patients after termination of cardiopulmonary bypass (T2). Although there were no significant differences in the values of conventional echocardiographic parameters during the intraoperative interval, GLS deteriorated significantly after CABG compared to pre-bypass assessment (T1 v T2, -13.4% ± 2.9 v -11.8% ± 2.9; p = 0.007). GCS improved significantly after surgery (T1 v T2, -19.4% (IQR -17.1% to -21.2%) v -22.8% (IQR -21.1% to -24.7%); p < 0.001) as well as aRot (T1 v T2, -9.7° (IQR -7.1° to -14.1°) v -14.5° (IQR -12.1° to -17.1°); p < 0.001), bRot (T1 v T2, 5.1° (IQR 3.8°-6.7°) v 7.2° (IQR 5.6°-8.2°); p = 0.02), and twist (T1 v T2, 15.8° (IQR 11.7°-19.4°) v 21.6° (IQR 19.2°-25.1°); p < 0.001), while GRS remained unchanged. There were no significant changes in the values of GLS, GCS, GRS, aRot, bRot, or twist, as well as in the values of 2D and 3D LV EF before and after sternal closure (T2 v T3). CONCLUSION: Beyond evaluation of longitudinal LV strain, measurements of circumferential and radial strain, as well as LV rotation and twist mechanics, were feasible in the intraoperative course of this study. Reduction of longitudinal function after on-pump CABG was compensated intraoperatively by improvement of GCS and rotation in the authors' group of patients. Perioperative assessment of GCS, GRS, as well as rotation and twist, might provide deeper insight into perioperative changes of cardiac mechanics.

Next-Generation Sequencing in Critically Ill COVID-19 Patients with Suspected Bloodstream Infections: A Retrospective Cohort Study.

BACKGROUND: Rapid pathogen identification and appropriate antimicrobial therapy are crucial in critically ill COVID-19 patients with bloodstream infections (BSIs). This study aimed to evaluate the diagnostic performance and potential therapeutic benefit of additional next-generation sequencing (NGS) of microbial DNA from plasma in these patients. METHODS: This monocentric descriptive retrospective study reviewed clinical data and pathogen diagnostics in COVID-19 ICU patients. NGS (DISQVER®) and blood culture (BC) samples were obtained on suspicion of BSIs. Data were reviewed regarding the adjustment of antimicrobial therapy and diagnostic procedures seven days after sampling and analyzed using the Chi²-test. RESULTS: Twenty-five cases with simultaneous NGS and BC sampling were assessed. The NGS positivity rate was 52% (13/25) with the detection of 23 pathogens (14 bacteria, 1 fungus, 8 viruses), and the BC positivity rate was 28% (7/25, 8 bacteria; p = 0.083). The NGS-positive patients were older (75 vs. 59.5 years; p = 0.03) with a higher prevalence of cardiovascular disease (77% vs. 33%; p = 0.03). These NGS results led to diagnostic procedures in four cases and to the commencement of four antimicrobial therapies in three cases. Empirical treatment was considered appropriate and continued in three cases. CONCLUSIONS: In COVID-19 patients with suspected BSIs, NGS may provide a higher positivity rate than BC and enable new therapeutic approaches.

Intraoperative Noninvasive Left Ventricular Myocardial Work Indices in Patients Undergoing On-Pump Coronary Artery Bypass Surgery.

OBJECTIVES: Noninvasive echocardiographic analysis of left ventricular (LV) myocardial work (MW) enables insights into cardiac mechanics, contractility, and efficacy beyond ejection fraction (EF) and global longitudinal strain (GLS). However, there are limited perioperative data on patients undergoing coronary artery bypass graft (CABG) surgery. The authors aimed to describe the feasibility and the intraoperative course of this novel assessment tool of ventricular function in these patients, and compare it to conventional 2-dimensional (2D) and 3-dimensional (3D) echocardiographic parameters and strain analysis. DESIGN: A prospective observational study. SETTING: At a single university hospital. PARTICIPANTS: Twenty-five patients with preoperative preserved LV and right ventricular function, sinus rhythm, without significant heart valve disease or pulmonary hypertension, and an uncomplicated intraoperative course scheduled for isolated on-pump CABG surgery. INTERVENTIONS: Transesophageal echocardiography (TEE) was performed intraoperatively after the induction of anesthesia (T1), after termination of cardiopulmonary bypass (T2), and after sternal closure (T3). All measurements were performed under stable hemodynamic conditions, in sinus rhythm or atrial pacing, and vasopressor support with norepinephrine ≤ 0.1 µg/kg/min. MEASUREMENTS AND MAIN RESULTS: The EchoPAC v204 software (GE Vingmed Ultrasound AS, Norway) was used for analysis of 2D and 3D LVEF, LV GLS, LV global work index (GWI), LV global constructive work (GCW), LV global wasted work (GWW), and LV global work efficiency (GWE). The MW analysis was feasible in all patients. Although there was no significant difference in the values of 2D and 3D EF during the intraoperative interval, GLS deteriorated significantly after CABG compared to assessment after induction of anesthesia (T1 v T2, -13.3 ± 3.0% v -11.6 ± 3.1%; p = 0.012). The GWI declined significantly after surgery (T1 v T2, 1,224 ± 312 mmHg% v 940 ± 267 mmHg%; p < 0.001), as well as GCW (T1 v T2, 1,460 ± 312 mmHg% v 1,244 ± 336 mmHg%; p = 0.005). The GWW increased after CABG (T1 v T2, 143 mmHg% (IQR 99-183) v 251 mmHg% (IQR 179-361); p < 0.001), and GWE decreased (T1 v T2, 89% (IQR 85-92) v 80% (IQR 75-87); p < 0.001). There were no significant changes in the values of 2D and 3D EF, GLS, GWI, GCW, GWW, and GWE before and after sternal closure (T2 v T3). CONCLUSION: The intraoperative analysis of noninvasive echocardiographically-assessed LV MW indices is feasible. In the short-term period after uncomplicated on-pump CABG, GLS, as well as global and constructive MW, decreased, whereas wasted work increased, resulting in a less efficient left ventricle. None of these aspects was detected by conventional echocardiographic parameters. Therefore, strain and MW analysis might be more sensitive parameters in detecting myocardial dysfunction by TEE in the perioperative setting, adding information on perioperative cardiac energetics.

Influence of Short and Long Hyperglycemia on Cardioprotection by Remote Ischemic Preconditioning-A Translational Approach.

The adverse impact of common diseases like diabetes mellitus and acute hyperglycemia on morbidity and mortality from myocardial infarction (MI) has been well documented over the past years of research. In the clinical setting, the relationship between blood glucose and mortality appears linear, with amplifying risk associated with increasing blood glucose levels. Further, this seems to be independent of a diagnosis of diabetes. In the experimental setting, various comorbidities seem to impact ischemic and pharmacological conditioning strategies, protecting the heart against ischemia and reperfusion injury. In this translational experimental approach from bedside to bench, we set out to determine whether acute and/or prolonged hyperglycemia have an influence on the protective effect of transferred human RIPC-plasma and, therefore, might obstruct translation into the clinical setting. Control and RIPC plasma of young healthy men were transferred to isolated hearts of young male Wistar rats in vitro. Plasma was administered before global ischemia under either short hyperglycemic (HGs Con, HGs RIPC) conditions, prolonged hyperglycemia (HGl Con, HGl RIPC), or under normoglycemia (Con, RIPC). Infarct sizes were determined by TTC staining. Control hearts showed an infarct size of 55 ± 7%. Preconditioning with transferred RIPC plasma under normoglycemia significantly reduced infarct size to 25 ± 4% (p < 0.05 vs. Con). Under acute hyperglycemia, control hearts showed an infarct size of 63 ± 5%. Applying RIPC plasma under short hyperglycemic conditions led to a significant infarct size reduction of 41 ± 4% (p < 0.05 vs. HGs Con). However, the cardioprotective effect of RIPC plasma under normoglycemia was significantly stronger compared with acute hyperglycemic conditions (RIPC vs. HGs RIPC; p < 0.05). Prolonged hyperglycemia (HGl RIPC) completely abolished the cardioprotective effect of RIPC plasma (infarct size 60 ± 7%; p < 0.05 vs. HGl Con; HGl Con 59 ± 5%).

Resveratrol therapy improves liver function via estrogen-receptors after hemorrhagic shock in rats.

BACKGROUND: Resveratrol may improve organ dysfunction after experimental hemorrhagic or septic shock, and some of these effects appear to be mediated by estrogen receptors. However, the influence of resveratrol on liver function and hepatic microcirculation after hemorrhagic shock is unknown, and a presumed mediation via estrogen receptors has not been investigated in this context. METHODS: Male Sprague-Dawley rats (200-300g, n = 14/group) underwent hemorrhagic shock for 90 min (MAP 35±5 mmHg) and were resuscitated with shed blood and Ringer's solution. Animals were treated intravenously with vehicle (1% EtOH), resveratrol (0.2 mg/kg), the unselective estrogen receptor antagonist ICI 182,780 (0.05 mg/kg) or resveratrol + ICI 182,780 prior to retransfusion. Sham-operated animals did not undergo hemorrhage but were treated likewise. After 2 hours of reperfusion, liver function was assessed either by plasma disappearance rate of indocyanine green (PDRICG) or evaluation of hepatic perfusion and hepatic integrity by intravital microscopy, serum enzyme as well as cytokine levels. RESULTS: Compared to vehicle controls, administration of resveratrol significantly improved PDRICG, hepatic perfusion index and hepatic integrity after hemorrhagic shock. The co-administration of ICI 182,780 completely abolished the protective effect only with regard to liver function. CONCLUSIONS: This study shows that resveratrol may improve liver function and hepatocellular integrity after hemorrhagic shock in rats; estrogen receptors mediate these effects at least partially.

Intravenous propofol, ketamine (ketofol) and rocuronium after sevoflurane induction provides long lasting anesthesia in ventilated rats.

Rats are commonly used animals for laboratory experiments and many experiments require general anesthesia. However, the lack of published and reproducible intravenous anesthesia protocols for rats results in unnecessary animal use to establish new anesthesia techniques across institutions. We therefore developed an anesthesia protocol with propofol, ketamine, and rocuronium for mechanically ventilated rats, and evaluated vital parameters and plasma concentrations. 15 male Sprague-Dawley rats underwent inhalation induction with sevoflurane and tracheal, venous and arterial cannulation. After established venous access, sevoflurane was substituted by propofol and ketamine (ketofol). Rocuronium was added under mechanical ventilation for 7 h. Drug dosages were stepwise reduced to prevent accumulation. All animals survived the observation period and showed adequate depth of anesthesia. Mean arterial pressure and heart rate remained within normal ranges. Median propofol plasma concentrations remained stable: 1, 4, 7 h: 2.0 (interquartile range (IQR): 1.8-2.2), 2.1 (1.8-2.2), 1.8 (1.6-2.1) µg/ml, whereas median ketamine concentrations slightly differed after 7 h compared to 1 h: 1, 4, 7 h: 3.7 (IQR: 3.5-4.5), 3.8 (3.3-4.1), 3.8 (3.0-4.1) µg/ml. Median rocuronium plasma concentrations were lower after 4 and 7 h compared to 1 h: 1, 4, 7 h: 3.9 (IQR: 3.5-4.9), 3.2 (2.7-3.3), 3.0 (2.4-3.4) µg/ml. Our anesthesia protocol provides stable and reliable anesthesia in mechanically ventilated rats for several hours.

Comparison of Volume-Guaranteed or -Targeted, Pressure-Controlled Ventilation with Volume-Controlled Ventilation during Elective Surgery: A Systematic Review and Meta-Analysis.

For perioperative mechanical ventilation under general anesthesia, modern respirators aim at combining the benefits of pressure-controlled ventilation (PCV) and volume-controlled ventilation (VCV) in modes typically named "volume-guaranteed" or "volume-targeted" pressure-controlled ventilation (PCV-VG). This systematic review and meta-analysis tested the hypothesis that PCV-VG modes of ventilation could be beneficial in terms of improved airway pressures (Ppeak, Pplateau, Pmean), dynamic compliance (Cdyn), or arterial blood gases (PaO2, PaCO2) in adults undergoing elective surgery under general anesthesia. Three major medical electronic databases were searched with predefined search strategies and publications were systematically evaluated according to the Cochrane Review Methods. Continuous variables were tested for mean differences using the inverse variance method and 95% confidence intervals (CI) were calculated. Based on the assumption that intervention effects across studies were not identical, a random effects model was chosen. Assessment for heterogeneity was performed with the χ2 test and the I2 statistic. As primary endpoints, Ppeak, Pplateau, Pmean, Cdyn, PaO2, and PaCO2 were evaluated. Of the 725 publications identified, 17 finally met eligibility criteria, with a total of 929 patients recruited. Under supine two-lung ventilation, PCV-VG resulted in significantly reduced Ppeak (15 studies) and Pplateau (9 studies) as well as higher Cdyn (9 studies), compared with VCV [random effects models; Ppeak: CI -3.26 to -1.47; p < 0.001; I2 = 82%; Pplateau: -3.12 to -0.12; p = 0.03; I2 = 90%; Cdyn: CI 3.42 to 8.65; p < 0.001; I2 = 90%]. For one-lung ventilation (8 studies), PCV-VG allowed for significantly lower Ppeak and higher PaO2 compared with VCV. In Trendelenburg position (5 studies), this effect was significant for Ppeak only. This systematic review and meta-analysis demonstrates that volume-targeting, pressure-controlled ventilation modes may provide benefits with respect to the improved airway dynamics in two- and one-lung ventilation, and improved oxygenation in one-lung ventilation in adults undergoing elective surgery.

Using supraglottic airways by paramedics for airway management in analogue microgravity increases speed and success of ventilation.

In the next few years, the number of long-term space missions will significantly increase. Providing safe concepts for emergencies including airway management will be a highly challenging task. The aim of the present trial is to compare different airway management devices in simulated microgravity using a free-floating underwater scenario. Five different devices for airway management [laryngeal mask (LM), laryngeal tube (LT), I-GEL, direct laryngoscopy (DL), and video laryngoscopy (VL)] were compared by n = 20 paramedics holding a diving certificate in a randomized cross-over setting both under free-floating conditions in a submerged setting (pool, microgravity) and on ground (normogravity). The primary endpoint was the successful placement of the airway device. The secondary endpoints were the number of attempts and the time to ventilation. A total of 20 paramedics (3 female, 17 male) participated in this study. Success rate was highest for LM and LT and was 100% both during simulated microgravity and normogravity followed by the I-GEL (90% during microgravity and 95% during normogravity). However, the success rate was less for both DL (60% vs. 95%) and VL (20% vs. 60%). Fastest ventilation was performed with the LT both in normogravity (13.7 ± 5.3 s; n = 20) and microgravity (19.5 ± 6.1 s; n = 20). For the comparison of normogravity and microgravity, time to ventilation was shorter for all devices on the ground (normogravity) as compared underwater (microgravity). In the present study, airway management with supraglottic airways and laryngoscopy was shown to be feasible. Concerning the success rate and time to ventilation, the optimum were supraglottic airways (LT, LM, I-GEL) as their placement was faster and associated with a higher success rate. For future space missions, the use of supraglottic airways for airway management seems to be more promising as compared to tracheal intubation by DL or VL.

Time to ventilation and success rate of airway devices in microgravity: A randomized crossover manikin-trial using an underwater setting.

BACKGROUND: Medical support for space exploration missions must prepare for severe medical events in conditions of microgravity. A key component to managing these events is techniques of airway management. The aim of the present trial is to compare airway management devices in simulated microgravity. METHODS: In this randomized cross-over trial (RCT), four different devices were compared under simulated microgravity conditions utilizing a neutrally buoyant free-floating underwater manikin and poolside in normal gravity (control group). The primary endpoint was the successful placement of the airway device. The secondary endpoints were the number of attempts and the duration of each attempt. RESULTS: A total of 20 participants performed placement of each device in both gravity conditions in an Airway mannequin. The fastest time to initial ventilation in simulated microgravity was possible with the laryngeal tube (18.9 ± 8 seconds) followed by laryngeal mask (20.1 ± 9 seconds). The I-gel® supraglottic airway device required substantially more time for successful insertion in simulated microgravity (35.4 ± 25 seconds) as did endotracheal tube intubation by direct laryngoscopy (70.4 ± 35 seconds). Simulated microgravity conditions prolonged time to initial ventilation by 3.3 seconds (LM), 3.9 seconds (LT), 19.9 seconds (I-gel) and 43.1 seconds (endotracheal intubation, ETI) when compared to poolside attempts in normogravity. CONCLUSION: In simulated microgravity conditions, use of the laryngeal tube or laryngeal mask provided the quickest time to initial ventilation, without deliberate tethering of the mannequin and rescuer to a fixed surface. Endotracheal intubation required significantly longer procedure times and, thus, was considered insufficient for clinical use in microgravity.

Performance of the laryngeal tube for airway management during cardiopulmonary resuscitation.

INTRODUCTION: Sudden cardiac arrest is one of the leading causes of death in Europe and the whole world. Effective chest compressions and advanced airway management have been shown to improve survival rates. Supraglottic airway devices such as the laryngeal tube (LT) are a well-known strategy for patients with cardiac arrest during both basic (BLS) and advanced life support (ALS). This systematic literature review aimed to summarize current data for using the LT when performing BLS and ALS. EVIDENCE ACQUISITION: Recent data on the use of the LT during cardiopulmonary resuscitation (CPR) was gathered by using the Medline database and a specific search strategy. Terms were used in various order and combinations without time restrictions. A total of N.=1005 studies were identified and screened by two experienced anesthesiologists/emergency physicians independently. Altogether, data of N.=19 relevant papers were identified and included in the analysis. EVIDENCE SYNTHESIS: Using the LT showed fast and easy placement with high success rates (76% to 94%) and was associated with higher short-term survival as compared to other strategies for initial airway management (2.2% vs. 1.4%). Quality of CPR such as chest compression fraction (CCF) before and after LT-insertion is improved (75% vs. 59%). For long-term survival, the LT showed lower survival rates. CONCLUSIONS: Especially as initial device of airway management (for inexperienced staff), the use of a LT is easy and results in a fast insertion. The advantages of the LT as compared to bag mask ventilation and endotracheal intubation are inhomogeneous in recent literature.

Depth of Neuromuscular Block Is Not Associated with Abdominal Wall Distention or Surgical Conditions during Gynecologic Laparoscopic Operations. A Prospective Trial.

The influence of the degree of a neuromuscular block (NMB) on surgical operating conditions during laparoscopic surgery is debated controversially. The extent of abdominal distension during the time course of the NMB was assessed as a new measurement tool. In 60 patients scheduled for gynecologic laparoscopic surgery, the increase of the abdominal wall length induced by the capnoperitoneum was measured at 5 degrees of the NMB: intense NMB-post-tetanic count (PTC) = 0; deep NMB-train-of-four count (TOF) = 0 and PTC = 1-5; medium NMB-PTC > 5 and TOF = 0-1; shallow NMB-TOF > 1; full recovery-train-of-four ratio TOFR > 90%. Simultaneously, the quality of operating conditions was assessed with a standardized rating scale (SRS) reaching from 1 (extremely poor conditions) to 5 (excellent conditions). Fifty patients could be included in the analysis. The abdominal wall length increased by 10-13 mm induced by the capnoperitoneum. SRS was higher during intense NMB (4.7 ± 0.5) vs. full recovery (4.5 ± 0.5) (mean ± SD; p = 0.025). Generally, an intense NMB did not increase abdominal wall length induced by capnoperitoneum. Additionally, its influence on the quality of surgical operating conditions seems to be of minor clinical relevance.

Activation of PKG and Akt Is Required for Cardioprotection by Ramelteon-Induced Preconditioning and Is Located Upstream of mKCa-Channels.

Ramelteon is a Melatonin 1 (MT1)-and Melatonin 2 (MT2)-receptor agonist conferring cardioprotection by pharmacologic preconditioning. While activation of mitochondrial calcium-sensitive potassium (mKCa)-channels is involved in this protective mechanism, the specific upstream signaling pathway of Ramelteon-induced cardioprotection is unknown. In the present study, we (1) investigated whether Ramelteon-induced cardioprotection involves activation of protein kinase G (PKG) and/or protein kinase B (Akt) and (2) determined the precise sequence of PKG and Akt in the signal transduction pathway of Ramelteon-induced preconditioning. Hearts of male Wistar rats were randomized and placed on a Langendorff system, perfused with Krebs-Henseleit buffer at a constant pressure of 80 mmHg. All hearts were subjected to 33 min of global ischemia and 60 min of reperfusion. Before ischemia, hearts were perfused with Ramelteon (Ram) with or without the PKG or Akt inhibitor KT5823 and MK2206, respectively (KT5823 + Ram, KT5823, MK2206 + Ram, MK2206). To determine the precise signaling sequence, subsequent experiments were conducted with the guanylate cyclase activator BAY60-2770 and the mKCa-channel activator NS1619. Infarct size was determined by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Ramelteon-induced infarct size reduction was completely blocked by KT5823 (p = 0.0012) and MK2206 (p = 0.0005). MK2206 with Ramelteon combined with BAY60-2770 reduced infarct size significantly (p = 0.0014) indicating that PKG activation takes place after Akt. Ramelteon and KT5823 (p = 0.0063) or MK2206 (p = 0.006) respectively combined with NS1619 also significantly reduced infarct size, indicating that PKG and Akt are located upstream of mKCa-channels. This study shows for the first time that Ramelteon-induced preconditioning (1) involves activation of PKG and Akt; (2) PKG is located downstream of Akt and (3) both enzymes are located upstream of mKCa-channels in the signal transduction pathway.

The Melatonin Receptor Agonist Ramelteon Induces Cardioprotection that Requires MT2 Receptor Activation and Release of Reactive Oxygen Species.

PURPOSE: The melatonin receptor (MT) agonist ramelteon has a higher affinity to MT1 than for MT2 receptors and induces cardioprotection by involvement of mitochondrial potassium channels. Activation of mitochondrial potassium channels leads to release of free radicals. We investigated whether (1) ramelteon-induced cardioprotection is MT2 receptor specific and (2) if free radicals are involved in ramelteon-induced cardioprotection. METHODS: Hearts of male Wistar rats were randomized, placed on a Langendorff system, and perfused with Krebs-Henseleit buffer at a constant pressure of 80 mmHg. All hearts were subjected to 33 min of global ischemia and 60 min of reperfusion. Before ischemia hearts were perfused with ramelteon (Ram) with or without the MT2 receptor inhibitor 4-phenyl-2-propionamidotetralin (4P-PDOT+Ram, 4P-PDOT). In subsequent experiments, ramelteon was administered together with the radical oxygen species (ROS) scavenger N-2-mercaptopropionylglycine (MPG+Ram). To determine whether the blockade of ramelteon-induced cardioprotection can be restored, we combined ramelteon and MPG with mitochondrial permeability transition pore (mPTP) inhibitor cyclosporine A (CsA) at different time points. Infarct size was determined by triphenyltetrazolium chloride (TTC) staining. RESULTS: Ramelteon-induced infarct size reduction was completely blocked by 4P-PDOT and MPG. Ramelteon and MPG combined with CsA before ischemia were not cardioprotective but CsA at the onset of reperfusion could restore infarct size reduction. CONCLUSIONS: This study shows for the first time that despite the higher affinity to MT1 receptors, (1) ramelteon-induced cardioprotection involves MT2 receptors, (2) cardioprotection requires ROS release, and (3) inhibition of the mPTP can restore infarct size reduction.

Characteristics of Dexmedetomidine Postconditioning in the Field of Myocardial Ischemia-Reperfusion Injury.

BACKGROUND: Timing and onset of myocardial ischemia are mostly unpredictable. Therefore, postconditioning could be an effective cardioprotective intervention. Because ischemic postconditioning is an invasive and not practicable treatment, pharmacological postconditioning would be a more suitable alternative cardioprotective measure. For the α2-adrenoreceptor agonist, dexmedetomidine postconditioning has been shown. However, data on a concentration-dependent effect of dexmedetomidine are lacking. Furthermore, it is unclear whether the time point and/or duration of dexmedetomidine administration in the reperfusion period is of relevance. We set out to determine whether infarct size reduction by dexmedetomidine is concentration dependent and whether time point and/or duration of dexmedetomidine application has an impact on the effect size of cardio protection. METHODS: Hearts of male Wistar rats were randomized and placed on a Langendorff system perfused with Krebs-Henseleit buffer at a constant pressure of 80 mm Hg. All hearts were subjected to 33 minutes of global ischemia and 60 minutes of reperfusion. In part I of the study, a concentration-response effect was determined by perfusing hearts with various concentrations of dexmedetomidine (0.3-100 nM) at the onset of reperfusion. Based on these results, part II of the study was conducted with 3 nM dexmedetomidine. Application of dexmedetomidine started directly at the onset of reperfusion (Dex60) and 15 minutes (Dex15), 30 minutes (Dex30), or 45 minutes (Dex45) after the start of reperfusion and lasted always until the end of the reperfusion period. Infarct size was determined by triphenyltetrazolium chloride staining. RESULTS: In part I, infarct size in control (Con) hearts was 62% ± 4%. Three-nanometer dexmedetomidine was the lowest most effective cardioprotective concentration and reduced infarct size to 24% ± 7% (P < .0001 versus Con). Higher concentrations did not confer stronger protection. Infarct size in control hearts from part II was 66% ± 6%. Different starting times and/or durations of application resulted in similar infarct size reduction (all P < .0001 versus Con). CONCLUSIONS: Postconditioning by dexmedetomidine is concentration dependent in ranges between 0.3 and 3 nM. Increased concentrations above 3 nM do not further enhance this cardioprotective effect. This cardioprotective effect is independent of time point and length of application in the reperfusion period.

Impact of Ca2+-Sensitive Potassium Channels in Levosimendan-Induced Postconditioning.

PURPOSE: Small and big conductance Ca2+-sensitive potassium (KCa) channels are involved in cardioprotective measures aiming at reducing myocardial reperfusion injury. For levosimendan, infarct size-reducing effects were shown. Whether activation of these channels is involved in levosimendan-induced postconditioning is unknown. We hypothesized that levosimendan exerts a concentration-dependent cardioprotective effect and that both types of Ca2+-sensitive potassium channels are involved. METHODS: In a prospective blinded experimental laboratory investigation, hearts of male Wistar rats were randomized and placed on a Langendorff system, perfused with Krebs-Henseleit buffer at a constant pressure of 80 mmHg. All hearts were subjected to 33 min of global ischemia and 60 min of reperfusion. At the onset of reperfusion, hearts were perfused with various concentrations of levosimendan (0.03-1 µM) in order to determine a concentration-response relationship. To elucidate the involvement of KCa-channels for the observed cardioprotection, in the second set of experiments, 0.3 µM levosimendan was administered in combination with the subtype-specific KCa-channel inhibitors paxilline (1 µM, big KCa-channel) and NS8593 (0.1 µM, small KCa-channel) respectively. Infarct size was determined by tetrazolium chloride (TTC) staining. RESULTS: Infarct size in controls was 60 ± 7% and 59 ± 6% respectively. Levosimendan at a concentration of 0.3 µM reduced infarct size to 30 ± 5% (P < 0.0001 vs. control). Higher concentrations of levosimendan did not induce a stronger effect. Paxilline but not NS8593 completely abolished levosimendan-induced cardioprotection while both substances alone had no effect on infarct size. CONCLUSIONS: Cardioprotection by levosimendan-induced postconditioning shows a binary phenomenon, either ineffective or with maximal effect. The cardioprotective effect requires activation of big but not small KCa channels.

Endogenous and Exogenous Melatonin Exposure Attenuates Hepatic MT1 Melatonin Receptor Protein Expression in Rat.

Melatonin receptors are highly relevant for the hepatoprotective effects of the pineal hormone melatonin after experimental hemorrhagic shock in rats. In this study, we sought to determine the spatial expression pattern and a putative regulation of two melatonin receptors, membrane bound type 1 and 2 (MT1 and MT2), in the liver of rats. In a male rat model (Sprague Dawley) of hemorrhage and resuscitation, we investigated the gene expression and protein of MT1 and MT2 in rat liver by utilizing real-time quantitative polymerase chain reaction, a western blot analysis, and immunohistochemistry. Plasma melatonin content was measured by an enzyme-linked immunosorbent assay. Male rats underwent hemorrhage and were resuscitated with shed blood and a Ringer's solution (n = 8 per group). After 90 min of hemorrhage, animals were given vehicle, melatonin, or ramelteon (each 1.0 mg/kg intravenously). Sham-operated controls did not undergo hemorrhage but were treated likewise. Plasma melatonin was significantly increased in all groups treated with melatonin and also after hemorrhagic shock. Only MT1, but not the MT2 messenger ribonucleic acid (mRNA) and protein, was detected in the rat liver. The MT1 protein was located in pericentral fields of liver lobules in sham-operated animals. After hemorrhagic shock and treatment with melatonin or ramelteon, the hepatic MT1 protein amount was significantly attenuated in all groups compared to sham controls (50% reduction; p < 0.001). With respect to MT1 mRNA, no significant changes were observed between groups (p = 0.264). Our results indicate that both endogenous melatonin exposure from hemorrhagic shock, as well as exogenous melatonin and ramelteon exposure, may attenuate melatonin receptors in rat hepatocytes, possibly by means of desensitization.

Plasma Disappearance Rate of Indocyanine Green for Determination of Liver Function in Three Different Models of Shock.

The measurement of the liver function via the plasma disappearance rate of indocyanine green (PDRICG) is a sensitive bed-side tool in critical care. Yet, recent evidence has questioned the value of this method for hyperdynamic conditions. To evaluate this technique in different hemodynamic settings, we analyzed the PDRICG and corresponding pharmacokinetic models after endotoxemia or hemorrhagic shock in rats. Male anesthetized Sprague-Dawley rats underwent hemorrhage (mean arterial pressure 35 ± 5 mmHg, 90 min) and 2 h of reperfusion, or lipopolysaccharide (LPS) induced moderate or severe (1.0 vs. 10 mg/kg) endotoxemia for 6 h (each n = 6). Afterwards, PDRICG was measured, and pharmacokinetic models were analyzed using nonlinear mixed effects modeling (NONMEM®). Hemorrhagic shock resulted in a significant decrease of PDRICG, compared with sham controls, and a corresponding attenuation of the calculated ICG clearance in 1- and 2-compartment models, with the same log-likelihood. The induction of severe, but not moderate endotoxemia, led to a significant reduction of PDRICG. The calculated ICG blood clearance was reduced in 1-compartment models for both septic conditions. 2-compartment models performed with a significantly better log likelihood, and the calculated clearance of ICG did not correspond well with PDRICG in both LPS groups. 3-compartment models did not improve the log likelihood in any experiment. These results demonstrate that PDRICG correlates well with ICG clearance in 1- and 2-compartment models after hemorrhage. In endotoxemia, best described by a 2-compartment model, PDRICG may not truly reflect the ICG clearance.

Beneficial effects of hirudotherapy in a chronic case of complex regional pain syndrome.

We report about hirudotherapy in a patient with chronic complex regional pain syndrome (CRPS) in the right hand. CRPS is a multifactorial disease associated with disabling pain as well as sensory and motor deficits. The optimal therapeutic management is based on personalized multimodal treatment approaches; however, hirudotherapy has not been described in the available literature. To date, we have completed five medicinal leech treatments. Altogether, hirudotherapy led to rapid and substantial relief of symptoms, especially with respect to pain intensity ratings and skin temperature asymmetries. In addition, the patient's active and passive agility of the affected limb improved obviously.