A Mixed-Methods Cohort Study Evaluating the Impact of a One-Day Well-Being Course for Anesthesia Providers Working in Low-Resource Settings.

BACKGROUND: Burnout, depression, and anxiety are increasingly recognized as common among health care providers. Risks for these conditions are exacerbated in low-resource settings by excessive workload, high disease burden, resource shortage, and stigma against mental health issues. Based on discussions and requests to learn more about burnout during the Vital Anaesthesia Simulation Training (VAST), our team developed VAST Wellbeing, a 1-day course for health care providers in low-resource settings to recognize and mitigate burnout and to promote personal and professional well-being. METHODS: This mixed-methods study used quantitative pre- and postcourse surveys using validated mental health measures and qualitative semistructured interviews to explore participants' experience of VAST Wellbeing during and after the course. Quantitative outcomes included burnout and professional fulfillment as measured by the Professional Fulfillment Index and general well-being as measured by the Warwick-Edinburgh Mental Wellbeing Scale. RESULTS: Twenty-six participants from 9 countries completed the study. In the immediate postcourse survey, study participants rated the course overall as "very good" (60.7%) and "excellent" (28.6%). Quantitative analysis showed no statistical differences in levels of work exhaustion, interpersonal disengagement, burnout, professional fulfillment, or general mental well-being 2 months after the course. Five themes on the impact of VAST Wellbeing were identified during qualitative analysis: (1) raising awareness, breaking taboos; (2) not feeling alone; (3) permission and capacity for personal well-being; (4) workplace empowerment; and (5) VAST Wellbeing was relevant, authentic, and needed. CONCLUSIONS: Causes of burnout are complex and multidimensional. VAST Wellbeing did not change measures of burnout and fulfillment 2 months postcourse but did have a meaningful impact by raising awareness, reducing stigma, fostering connection, providing skills to prioritize personal well-being, and empowering people to seek workplace change.

Lung-Protective Ventilation Attenuates Mechanical Injury While Hypercapnia Attenuates Biological Injury in a Rat Model of Ventilator-Associated Lung Injury.

Background and Objective: Lung-protective mechanical ventilation is known to attenuate ventilator-associated lung injury (VALI), but often at the expense of hypoventilation and hypercapnia. It remains unclear whether the main mechanism by which VALI is attenuated is a product of limiting mechanical forces to the lung during ventilation, or a direct biological effect of hypercapnia. Methods: Acute lung injury (ALI) was induced in 60 anesthetized rats by the instillation of 1.25 M HCl into the lungs via tracheostomy. Ten rats each were randomly assigned to one of six experimental groups and ventilated for 4 h with: 1) Conventional HighV E Normocapnia (high VT, high minute ventilation, normocapnia), 2) Conventional Normocapnia (high VT, normocapnia), 3) Protective Normocapnia (VT 8 ml/kg, high RR), 4) Conventional iCO 2 Hypercapnia (high VT, low RR, inhaled CO2), 5) Protective iCO 2 Hypercapnia (VT 8 ml/kg, high RR, added CO2), 6) Protective endogenous Hypercapnia (VT 8 ml/kg, low RR). Blood gasses, broncho-alveolar lavage fluid (BALF), and tissue specimens were collected and analyzed for histologic and biologic lung injury assessment. Results: Mild ALI was achieved in all groups characterized by a decreased mean PaO2/FiO2 ratio from 428 to 242 mmHg (p < 0.05), and an increased mean elastance from 2.46 to 4.32 cmH2O/L (p < 0.0001). There were no differences in gas exchange among groups. Wet-to-dry ratios and formation of hyaline membranes were significantly lower in low VT groups compared to conventional tidal volumes. Hypercapnia reduced diffuse alveolar damage and IL-6 levels in the BALF, which was also true when CO2 was added to conventional VT. In low VT groups, hypercapnia did not induce any further protective effect except increasing pulmonary IL-10 in the BALF. No differences in lung injury were observed when hypercapnia was induced by adding CO2 or decreasing minute ventilation, although permissive hypercapnia decreased the pH significantly and decreased liver histologic injury. Conclusion: Our findings suggest that low tidal volume ventilation likely attenuates VALI by limiting mechanical damage to the lung, while hypercapnia attenuates VALI by limiting pro-inflammatory and biochemical mechanisms of injury. When combined, both lung-protective ventilation and hypercapnia have the potential to exert an synergistic effect for the prevention of VALI.

Qualities of Effective Vital Anaesthesia Simulation Training Facilitators Delivering Simulation-Based Education in Resource-Limited Settings.

BACKGROUND: Lack of access to safe and affordable anesthesia and surgical care is a major contributor to avoidable death and disability across the globe. Effective education initiatives are a viable mechanism to address critical skill and process gaps in perioperative teams. Vital Anaesthesia Simulation Training (VAST) aims to overcome barriers limiting widespread application of simulation-based education (SBE) in resource-limited environments, providing immersive, low-cost, multidisciplinary SBE and simulation facilitator training. There is a dearth of knowledge regarding the factors supporting effective simulation facilitation in resource-limited environments. Frameworks evaluating simulation facilitation in high-income countries (HICs) are unlikely to fully assess the range of skills required by simulation facilitators working in resource-limited environments. This study explores the qualities of effective VAST facilitators; knowledge gained will inform the design of a framework for assessing simulation facilitators working in resource-limited contexts and promote more effective simulation faculty development. METHODS: This qualitative study used in-depth interviews to explore VAST facilitators' perspectives on attributes and practices of effective simulation in resource-limited settings. Twenty VAST facilitators were purposively sampled and consented to be interviewed. They represented 6 low- and middle-income countries (LMICs) and 3 HICs. Interviews were conducted using a semistructured interview guide. Data analysis involved open coding to inductively identify themes using labels taken from the words of study participants and those from the relevant literature. RESULTS: Emergent themes centered on 4 categories: Persona, Principles, Performance and Progression. Effective VAST facilitators embody a set of traits, style, and personal attributes (Persona) and adhere to certain Principles to optimize the simulation environment, maximize learning, and enable effective VAST Course delivery. Performance describes specific practices that well-trained facilitators demonstrate while delivering VAST courses. Finally, to advance toward competency, facilitators must seek opportunities for skill Progression.Interwoven across categories was the finding that effective VAST facilitators must be cognizant of how context, culture, and language may impact delivery of SBE. The complexity of VAST Course delivery requires that facilitators have a sensitive approach and be flexible, adaptable, and open-minded. To progress toward competency, facilitators must be open to self-reflection, be mentored, and have opportunities for practice. CONCLUSIONS: The results from this study will help to develop a simulation facilitator evaluation tool that incorporates cultural sensitivity, flexibility, and a participant-focused educational model, with broad relevance across varied resource-limited environments.

The prophylactic use of fibrinogen concentrate in high-risk cardiac surgery.

BACKGROUND: Perioperative blood loss is a major contributor to morbidity and mortality in cardiac surgery. Plasma fibrinogen levels play an essential role in hemostasis and deplete quickly during hemorrhage. The objective of this study was to determine whether prophylactic fibrinogen concentrate administration lowers overall blood product transfusion requirements in high-risk cardiac surgery in patients with low fibrinogen plasma levels. METHODS: The study was performed in a prospective, randomized, and double-blinded design. The investigation included 62 patients undergoing elective, high-risk cardiac surgery. After weaning from cardiopulmonary bypass and reversal of heparin patients received either fibrinogen concentrate or placebo. The primary outcome variable was overall blood product usage 24 hours after intervention. RESULTS: The fibrinogen group received numerically fewer total units of blood products than the placebo group, but the difference was not statistically or clinically significant (for groups n = 27; n = 29 and 19 vs 37 units, respectively, P = .908). The overall transfusion rate in both groups was significantly lower than the institutional average suggested (fibrinogen group 26%, placebo group 28%). The fibrinogen group showed significantly higher fibrinogen levels (2.38 vs 1.83 g/L (end of surgery), P < .001; 3.33 vs 2.68 g/L (12 hours after intervention), P = .003) and improved viscoelastic coagulation parameters (FIBTEM MCF, 27 vs 23 mm, P = .022). CONCLUSION: This randomized, controlled trial demonstrates that point-of-care guided and prophylactic treatment with fibrinogen concentrate does not reduce transfusion of blood products in a setting of unexpectedly low transfusion rate as tested in this cohort, but may improve coagulation parameters in the setting of high-risk cardiac surgery.

Promoting anaesthetisia providers' non-technical skills through the Vital Anaesthesia Simulation Training (VAST) course in a low-resource setting.

BACKGROUND: Short educational programmes are important in building global anaesthesia workforce capacity. The Vital Anaesthesia Simulation Training (VAST) course is a 3-day immersive simulation-based programme concentrating on core clinical challenges and non-technical skills required by anaesthesia providers in low-resource settings. METHODS: This mixed methods study prospectively evaluated the impact of VAST in Rwanda. Anaesthetists' Non-Technical Skills (ANTS) scores were quantitatively assessed for 30 course participants at three time points (pre-, post-, and 4 months after VAST). Qualitative data were gathered during focus groups (4 months after VAST) to learn of participants' experiences implementing new knowledge into clinical practice. RESULTS: The ANTS total scores improved from pre- (11.0 [2.3]) (mean [standard deviation]) to post-test (14.0 [1.6]), and improvements were maintained at retention (14.2 [1.7]). A similar pattern was observed when data were analysed using the four ANTS categories (all P<0.001). The key theme that emerged during focus group discussions was that the use of cognitive aids and clinical algorithms, repeated and reinforced across simulated scenarios, encouraged a systematic approach to patient care. The participants attributed the systematic approach to improving their problem-solving skills and confidence, particularly during emergencies. They found value in well-functioning teams and shared decision-making. After VAST, the participants described empowerment to advocate for better patient care and system improvement. CONCLUSIONS: VAST offers a simulation-based training to anaesthesia providers working in low-resource settings. Skills retention and self-reported application of learning into the workplace reflect the scope of impact of this training.

Clinical relevance of early sublingual microcirculation monitoring in septic shock patients.

INTRODUCTION: Although microcirculation dysfunction plays unique role in septic shock, translation of microcirculation to clinical practices is limited by current semi-quantities analysis and unclear clinical relevance of microcirculation monitoring. Our aim was to critically evaluate the characteristic nature and relevant clinical important of microcirculation. EVIDENCE ACQUISITION: Pubmed (2000 to August 2015) were searched to identify observation, case-control, intervention and randomized clinical studies evaluating the relationship between microcirculation alterations and mortality, morbidity and drug responses. The STROBE and CONSORT Statement for assessment of the quality of included studies. EVIDENCE SYNTHESIS: We examined results from 17 observations, 4 randomized controlled trials and one case report published studies. This data set comprised of 637 patients. Early septic shock is associated with hypoperfusion and heterogeneous microcirculation that is associated with hyperlactemia and metabolic acidosis. The evidence on clinical relevance of microcirculation is less striking, mainly due to the limited number of studies and problems related to the methodological protocol of the studies and currently semi-quantitative analysis technique. In particular the baseline and time course of microcirculation alteration appears to be controversial. CONCLUSION: There is lack of evidences of clinical importance of early microcirculation monitoring and mechanism of microcirculation dysfunction in septic shock patients. This could be due to the methodological protocol of the studies and currently semi-quantitative analysis technique.

Preliminary clinical evaluation of automated analysis of the sublingual microcirculation in the assessment of patients with septic shock: Comparison of automated versus semi-automated software.

INTRODUCTION: The outcome of patients in septic shock has been shown to be related to changes within the microcirculation. Modern imaging technologies are available to generate high resolution video recordings of the microcirculation in humans. However, evaluation of the microcirculation is not yet implemented in the routine clinical monitoring of critically ill patients. This is mainly due to large amount of time and user interaction required by the current video analysis software. The aim of this study was to validate a newly developed automated method (CCTools®) for microcirculatory analysis of sublingual capillary perfusion in septic patients in comparison to standard semi-automated software (AVA3®). METHODS: 204 videos from 47 patients were recorded using incident dark field (IDF) imaging. Total vessel density (TVD), proportion of perfused vessels (PPV), perfused vessel density (PVD), microvascular flow index (MFI) and heterogeneity index (HI) were measured using AVA3® and CCTools®. RESULTS: Significant differences between the numeric results obtained by the two different software packages were observed. The values for TVD, PVD and MFI were statistically related though. CONCLUSION: The automated software technique successes to show septic shock induced microcirculation alterations in near real time. However, we found wide degrees of agreement between AVA3® and CCTools® values due to several technical factors that should be considered in the future studies.

Low-Cost Simulation to Teach Anesthetists' Non-Technical Skills in Rwanda.

BACKGROUND: Safe anesthesia care is challenging in developing countries where there are shortages of personnel, drugs, equipment, and training. Anesthetists' Non-technical Skills (ANTS)-task management, team working, situation awareness, and decision making-are difficult to practice well in this context. Cesarean delivery is the most common surgical procedure in sub-Saharan Africa. This pilot study investigates whether a low-cost simulation model, with good psychological fidelity, can be used effectively to teach ANTS during cesarean delivery in Rwanda. METHODS: Study participants were anesthesia providers working in a tertiary referral hospital in Rwanda. Baseline observations were conducted for 20 anesthesia providers during cesarean delivery using the established ANTS framework. After the first observation set was complete, participants were randomly assigned to either simulation intervention or control groups. The simulation intervention group underwent ANTS training using low-cost high psychological fidelity simulation with debriefing. No training was offered to the control group. Postintervention observations were then conducted in the same manner as the baseline observations. RESULTS: The primary outcome was the overall ANTS score (maximum, 16). The median (range) ANTS score of the simulation group was 13.5 (11-16). The ANTS score of the control group was 8 (8-9), with a statistically significant difference (P = .002). Simulation participants showed statistically significant improvement in subcategories and in the overall ANTS score compared with ANTS score before simulation exposure. CONCLUSIONS: Rwandan anesthesia providers show improvement in ANTS practice during cesarean delivery after 1 teaching session using a low-cost high psychological fidelity simulation model with debriefing.

Effects of haemoglobin levels on the sublingual microcirculation in pregnant women.

Anemia in pregnant women is associated with increased maternal and perinatal mortality and represents an important economic burden in many developing countries. Our goal was to evaluate the impact of anemia on the capillary network during pregnancy. Therefore, we compared microcirculatory parameters of anemic pregnant study participants to that of non-anemic pregnant women employing sublingual microcirculation video imaging technology and novel automated video analysis software.Non-anemic (n = 7) and anemic (n = 44) pregnant women were enrolled in the study at second and third trimesters. Video imaging was applied to the sublingual mucosal surface in five visual fields. The resultant videos were analyzed automatically, avoiding observer bias. Total vessel density (TVD), perfused vessel density (PVD) and proportion of perfused vessels (PPV) were calculated by the software. Both, mean TVD and PVD were significantly increased in the anemic pregnant group, while the PPV was not significantly different. Significant negative correlations were observed between haemoglobin (Hb) levels and both, TVD and PVD. Haemoglobin level seems to play an important determinant role in restructuring the capillary network. An effect that could compensate the impaired tissue oxygen delivery associated with anemia during pregnancy.

Endocarditis is not an Independent Predictor of Blood Transfusion in Aortic Valve Replacement Patients With Severe Aortic Regurgitation.

OBJECTIVE: This study sought to evaluate if the presence of endocarditis was independently associated with increased perioperative blood transfusion in patients undergoing aortic valve replacements (AVR) with aortic regurgitation. DESIGN: This was a retrospective study. SETTING: Large Canadian tertiary care hospital. PARTICIPANTS: Six hundred sixty-two consecutive patients with aortic regurgitation score of 3 or higher undergoing AVR from 1995 to 2012. INTERVENTIONS: No interventions were performed in this retrospective study. MEASUREMENTS AND MAIN RESULTS: After REB approval, data were obtained from a center-specific database. Univariate analysis was performed to identify variables that may be associated with transfusion of any allogeneic blood product perioperatively. A multivariate logistic regression was generated to identify independent predictors of perioperative transfusion. Unadjusted transfusion rates in patients with no endocarditis and with endocarditis were 32% and 70% (p<0.001), respectively. Independent predictors of any transfusion were moderate-to-severe preoperative anemia, preoperative renal failure, non-isolated AVR, age>70, urgent/emergent surgery, BMI<25, and female sex. Endocarditis was not an independent predictor of transfusion (OR = 0.748; 95% CI = 0.35-1.601). CONCLUSIONS: In patients undergoing AVR, unadjusted perioperative transfusion rates were higher when endocarditis was present. However, after adjustment, aortic valve endocarditis was not independently associated with blood transfusion. The authors' observation could be explained by the higher prevalence of many independent predictors of transfusion, such as comorbidities or more complex surgery, within the endocarditis group. Thus, AV endocarditis, in the absence of other risk factors, was not associated with increased perioperative transfusion risk.

Development of a simulation and skills centre in East Africa: a Rwandan-Canadian partnership.

Simulation replicates clinical experiences without patient risk; it remains uncommon in lower-income countries. We outline the creation of Rwanda's first centre for simulation and skills training. We secured funding for renovations, equipment and staff; curricula were developed, tested, and refined; local clinicians were trained to teach. In 13 months the centre provided 2,377 learning-encounters and 822 hours of training to Rwandan health care professionals. Our strategy represents an adaptable model for simulation and skills centre development in low-resources settings.

Physostigmine reverses disturbances of the intestinal microcirculation during experimental endotoxemia.

Intestinal microcirculatory disturbances play an important role in the pathophysiology of sepsis. A neural anti-inflammatory pathway has been suggested as a potential target for therapy that may dampen systemic inflammation. The aim of this study is to investigate the effects of physostigmine, a cholinesterase inhibitor, on the intestinal microcirculation and vascular contractility in experimental endotoxemia. Endotoxemia was induced in Lewis rats by intravenous lipopolysaccharide (LPS) administration. Animals were treated with either physostigmine or saline (control) following LPS challenge. The intestinal microcirculation, including leukocyte-endothelial interaction, functional capillary density (FCD) and non-perfused capillary density (NCD), was examined by intravital microscopy (IVM) 2 hours after LPS administration. The impact of physostigmine on vascular contractility of rat aortic rings was examined by in vitro myography. Physostigmine significantly reduced the number of adhering leukocytes in intestinal submucosal venules (V1 venules: -61%, V3 venules: -36%) of LPS animals. FCD was significantly increased by physostigmine treatment (circular muscle layer: +180%, longitudinal muscle layer: +162%, mucosa: +149%). Low concentrations of physostigmine produced significant contraction of aortic ring preparations, whereas high concentrations produced relaxation. In conclusion, physostigmine treatment significantly improved the intestinal microcirculation in experimental endotoxemia by reducing leukocyte adhesion and increasing FCD.

Non-technical skills of anaesthesia providers in Rwanda: an ethnography.

INTRODUCTION: Patient safety depends on excellent practice of anaesthetists' non-technical skills (ANTS). The ANTS framework has been validated in developed countries but there is no literature on the practice of ANTS in low-income countries. This study examines ANTS in this unexplored context. METHODS: This qualitative ethnographic study used observations of Rwandan anaesthesia providers and in-depth interviews with both North American and Rwandan anaesthesia providers to understand practice of ANTS in Rwanda. RESULTS: Communication is central to the practice of ANTS. Cultural factors in Rwanda, such as lack of assertiveness and discomfort taking leadership, and the strains of working in a resource-limited environment hinder the unfettered and focused communication needed for excellent anaesthesia practice. CONCLUSION: Despite the challenges, anaesthesia providers are able to coordinate activities when good communication is actively encouraged. Future teaching interventions should address leadership and communication skills through encouraging both role definition and speaking up for patient safety.

Cannabinoid receptor 1 inhibition causes seizures during anesthesia induction in experimental sepsis.

We report on seizures during anesthesia induction in animals treated with a cannabinoid receptor 1 (CB1R) antagonist for experimental sepsis. Animals received surgery for colon ascendens stent peritonitis-induced sepsis or sham surgery followed by treatment of CB1R antagonist, CB1R agonist, or placebo. Fourteen hours later, animals received pentobarbital or ketamine for anesthesia induction and animal behavior was observed. Tonic-clonic seizures were observed in 5 of 12 septic animals (42%) treated with CB1R antagonist after induction of anesthesia with pentobarbital. The data suggest that CB1R inhibition in combination with pentobarbital may increase the incidence of anesthetic-induced seizures in the case of sepsis.

Activated protein C improves pial microcirculation in experimental endotoxemia in rats.

INTRODUCTION: The brain is one of the first organs affected clinically in sepsis. Microcirculatory alterations are suggested to be a critical component in the pathophysiology of sepsis. The aim of this study was to investigate the effects of recombinant human activated protein C (rhAPC) on the pial microcirculation in experimental endotoxemia using intravital microscopy. Our hypothesis is rhAPC protects pial microcirculation in endotoxemia. METHODS: Endotoxemia was generated in Lewis rats with intravenous injection of lipopolysaccharide (LPS, 5 mg/kg i.v.). Dura mater was removed through a cranial window to expose pial vessels on the brain surface. The microcirculation, including leukocyte-endothelial interaction, functional capillary density (FCD) and plasma extravasation of pial vessels was examined by fluorescent intravital microscopy (IVM) 2 h after administration of LPS, LPS and rhAPC or equivalent amount of saline (used as Control group). Plasma cytokine levels of interleukin 1 alpha (IL1-α), tumor necrosis factor-α (TNF-α), interferon γ (IFN-γ), Monocyte chemotactic protein-1 (MCP-1) and Granulocyte-macrophage colony-stimulating factor (GM-CSF) were evaluated after IVM. RESULTS: LPS challenge significantly increased leukocyte adhesion (773±190 vs. 592±152 n/mm(2) Control), decreased FCD (218±54 vs. 418±74 cm/cm(2) Control) and increased proinflammatory cytokine levels (IL-1α: 5032±1502 vs. 8±21 pg/ml; TNF-α: 1823±1007 vs. 168±228 pg/ml; IFN-γ: 785±434 vs. 0 pg/ml; GM-CSF: 54±52 vs. 1±3 pg/ml) compared to control animals. rhAPC treatment significantly reduced leukocyte adhesion (599±111 n/mm(2)), increased FCD (516±118 cm/cm(2)) and reduced IL-1α levels (2134±937 pg/ml) in the endotoxemic rats. CONCLUSION: APC treatment significantly improves pial microcirculation by reducing leukocyte adhesion and increasing FCD.

Cannabinoid receptor 2 activation reduces intestinal leukocyte recruitment and systemic inflammatory mediator release in acute experimental sepsis.

INTRODUCTION: Cannabinoid receptor 2 (CB2R) expression is upregulated during sepsis. However, there are conflicting results regarding the effects of CB2R modulation in the hyperinflammatory phase of the disease. The aim of this study was therefore to investigate the effects of CB2R manipulation on leukocyte activation within the intestinal microcirculation in two acute experimental sepsis models. METHODS: In the endotoxemia model we studied four groups of Lewis rats: controls, lipopolysaccharide (LPS), LPS + CB2R agonist HU308 (2.5 mg/kg), and LPS + CB2R antagonist AM630 (2.5 mg/kg). In the colon ascendens stent peritonitis (CASP)-induced sepsis model we also studied four groups: sham group, CASP and CASP + CB2R agonist (HU308, 2.5 or 10 mg/kg). Intravital microscopy was performed 2 hours following LPS/placebo administration or 16 hours following CASP/sham surgery to quantify intestinal leukocyte recruitment. Additionally, hemodynamic monitoring, histological examinations and measurements of inflammatory mediators were performed. RESULTS: HU308 administration significantly reduced intestinal leukocyte adhesion in both acute sepsis models. The systemic levels of inflammatory mediators were significantly reduced by 10 mg/kg HU308 treatment in CASP animals. CONCLUSION: CB2R activation reduces leukocyte activation and systemic release of inflammatory mediators in acute experimental sepsis. Drugs targeting the CB2R pathway may have therapeutic potential in sepsis.

Intravenous free and dipeptide-bound glutamine maintains intestinal microcirculation in experimental endotoxemia.

OBJECTIVE: The administration of glutamine (Gln), which is depleted in critical illness, is associated with an improvement of gut metabolism, structure, and function. The aim of the present study was to evaluate the effects of intravenous Gln and its galenic formulation, l-alanyl-l-glutamine dipeptide (AlaGln), on the intestinal microcirculation during experimental endotoxemia using intravital fluorescence microscopy. Gln or AlaGln administration was performed as pretreatment or post-treatment, respectively. To identify further the underlying mechanisms, amino acid levels were studied. METHODS: Sixty male Lewis rats were randomly divided into six groups (n = 10/group): control, LPS (lipopolysaccharide 5 mg/kg intravenously), Gln/LPS (LPS animals pretreated with Gln 0.75 g/kg Gln intravenously), AlaGln/LPS (LPS animals pretreated with AlaGln intravenously, 0.75 g/kg Gln content), LPS/Gln (LPS animals post-treated with Gln 0.75 g/kg intravenously), and LPS/AlaGln (LPS animals post-treated with AlaGln intravenously, 0.75 g/kg Gln content). Two hours after the endotoxin challenge, the microcirculation of the terminal ileum was studied using intravital fluorescence microscopy. Blood samples were drawn at the beginning, during, and the end of the experiment to determine the amino acid levels. RESULTS: The Gln and AlaGln pre- and post-treatment, respectively, prevented the LPS-induced decrease in the functional capillary density of the intestinal muscular and mucosal layers (P < 0.05). The number of adherent leukocytes in the submucosal venules was significantly attenuated after the Gln and AlaGln pre- and post-treatment (P < 0.05). CONCLUSION: The Gln and AlaGln administrations improved the intestinal microcirculation by increasing the functional capillary density of the intestinal wall and decreasing the submucosal leukocyte activation.

Physiologic and biologic characteristics of three experimental models of acute lung injury in rats.

BACKGROUND: Strategies to attenuate ventilator-associated lung injury have been tested in various experimental methods of acute lung injury (ALI). Conclusions are often drawn from physiologic and biologic effects, but the influence of the model on these results is not known. Our aim in this study was to characterize frequently used models of experimental ALI. METHODS: Twenty Sprague Dawley rats were anesthetized and their lungs mechanically ventilated for 5 hours. Three models of ALI (surfactant washout, acid aspiration, and high tidal volume ventilation) were investigated with regard to hemodynamics, respiratory mechanics, gas exchange, lung pathology, and inflammatory reactions. Animals without ALI served as controls. RESULTS: Five animals in each group were analyzed. Dynamic compliance and Pao(2)/fraction of inspired oxygen ratio decreased by at least 50% in all groups after 1 hour. Whereas compliance remained decreased in all models, oxygenation returned to baseline values in the lavage group after 5 hours. Diffuse alveolar damage was worse in the high tidal volume model and was not different between the control and lavage animals. Interleukin-6 was increased in bronchoalveolar lavage fluid in the aspiration and high tidal volume models. CONCLUSIONS: Although comparable physiologic effects meeting acute respiratory distress syndrome criteria were achieved in all models, the biologic responses varied among lung injury models. The acid aspiration model created both respiratory and inflammatory responses typically seen in ALI; these data suggest that it may be the most clinically applicable model to study the intermediate-term effects of ventilator-associated lung injury in rats.

Inhibition of lectin-like oxidized low-density lipoprotein receptor-1 reduces leukocyte adhesion within the intestinal microcirculation in experimental endotoxemia in rats.

INTRODUCTION: Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), the major endothelial receptor for oxidized low-density lipoprotein, is also involved in leukocyte recruitment. Systemic leukocyte activation in sepsis represents a crucial factor in the impairment of the microcirculation of different tissues, causing multiple organ failure and subsequently death. The aim of our experimental study was to evaluate the effects of LOX-1 inhibition on the endotoxin-induced leukocyte adherence and capillary perfusion within the intestinal microcirculation by using intravital microscopy (IVM). METHODS: We used 40 male Lewis rats for the experiments. Ten placebo-treated animals served as a control. Thirty animals received 5 mg/kg lipopolysaccharide (LPS) intravenously. Ten endotoxemic rats remained untreated. In 10 LPS animals, we administered additionally 10 mg/kg LOX-1 antibodies. Ten further LPS animals received a nonspecific immunoglobulin (rat IgG) intravenously. After 2 hours of observation, intestinal microcirculation was evaluated by using IVM; the plasma levels of monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-alpha (TNF-α) were determined; and LOX-1 expression was quantified in intestinal tissue with Western blot and reverse-transcription polymerase chain reaction (PCR). RESULTS: LOX-1 inhibition significantly reduced LPS-induced leukocyte adhesion in intestinal submucosal venules (P < 0.05). At the protein and mRNA levels, LOX-1 expression was significantly increased in untreated LPS animals (P < 0.05), whereas in animals treated with LOX-1 antibody, expression of LOX-1 was reduced (P < 0.05). MCP-1 plasma level was reduced after LOX-1 antibody administration. CONCLUSIONS: Inhibition of LOX-1 reduced leukocyte activation in experimental endotoxemia. LOX-1 represents a novel target for the modulation of the inflammatory response within the microcirculation in sepsis.

Argatroban administration reduces leukocyte adhesion and improves capillary perfusion within the intestinal microcirculation in experimental sepsis.

Co-activation of pro-coagulatory pathways in sepsis may result in disseminated intravascular coagulation and contributes to microvascular dysfunction. We investigated the effects of the direct thrombin inhibitor, argatroban (ARG), on the sepsis-induced impairment of the intestinal microcirculation (capillary perfusion, leukocyte adhesion) and the vascular contractility in rats. Forty male Lewis rats were randomly assigned to one of four groups: sham surgery (SHAM), experimental sepsis (colon ascendens stent peritonitis--CASP), CASP+ARG, and SHAM+ARG. At 16 hours after colon stent insertion (or sham surgery), 2 mg/kg argatroban or buffer were given intravenously, and 1 hour thereafter, intravital microscopy was performed. In addition, experiments to study the impact of ARG on vascular contractility were conducted in vitro . ARG administration in CASP rats significantly increased functional capillary density in mucosal (+128%) and muscular layers (longitudinal: +42%; circular: +64%) and decreased the number of firmly adhering leukocytes in the intestinal submucosa compared to untreated animals. In vitro findings indicated a vasodilating effect of ARG. ARG administration during experimental sepsis improved intestinal microcirculation by preserving functional capillary density, an indicator of microvascular perfusion, and by reducing leukocyte adherence to the endothelium in submucosal venules.