The Usefulness of Microcirculatory Assessment After Cardiac Surgery: Illustrative Case Report.

Cardiac surgery causes a series of disturbances in human physiology. The correction of systemic hemodynamic variables is frequently ineffective in improving microcirculatory perfusion and delivering oxygen to the tissues. We present the case of a 52-year-old male submitted to mitral valve replacement (metallic valve) and subaortic membrane resection. Sublingual microcirculatory density and perfusion were evaluated using a handheld CytoCam camera before surgery and in the early postoperative period. In this case, systemic hemodynamic variables were compromised despite an actual improvement in the microcirculatory parameters in comparison to the preoperative evaluation, possibly due to the correction of the structural cardiac defects.

Relationship between sublingual varices and hypertension: a systematic review and meta-analysis.

BACKGROUND: Previous research has investigated the connection between sublingual varices (SV) and cardiovascular disease, aging, and smoking. However, it is still unclear whether arterial hypertension affects the presence of SV. This meta-analysis aimed to investigate the relationship between hypertension and the presence of SV. METHODS: The literature search was performed using PubMed, Web of Science, Scopus, Google Scholar, and Embase for cross-sectional studies until July 2023. PRISMA guidelines were used for article selection. A meta-analysis using standardized mean differences by a random effects model was conducted to pool studies. RESULTS: A total of 568 articles were retrieved, of which twelve were included in the meta-analysis. Cumulatively, 2543 samples in the case group (1185 with hypertension) and 3897 samples (821 with hypertension) were studied in the control group. Using the random effects model, the pooled odds ratio (OR) revealed a significant association between hypertension and sublingual varices (OR = 2.66; 95% CI: 1.69-4.18). CONCLUSION: The meta-analysis showed a significant and positive association between sublingual varices and hypertension. SV's presence could be used by dentists as a non-invasive indicator of hypertension screening.

The microcirculation in perioperative medicine: a narrative review.

The microcirculation describes the network of the smallest vessels in our cardiovascular system. On a microcirculatory level, oxygen delivery is determined by the flow of oxygen-carrying red blood cells in a given single capillary (capillary red blood cell flow) and the density of the capillary network in a given tissue volume (capillary vessel density). Handheld vital videomicroscopy enables visualisation of the capillary bed on the surface of organs and tissues but currently is only used for research. Measurements are generally possible on all organ surfaces but are most often performed in the sublingual area. In patients presenting for elective surgery, the sublingual microcirculation is usually intact and functional. Induction of general anaesthesia slightly decreases capillary red blood cell flow and increases capillary vessel density. During elective, even major, noncardiac surgery, the sublingual microcirculation is preserved and remains functional, presumably because elective noncardiac surgery is scheduled trauma and haemodynamic alterations are immediately treated by anaesthesiologists, usually restoring the macrocirculation before the microcirculation is substantially impaired. Additionally, surgery is regional trauma and thus likely causes regional, rather than systemic, impairment of the microcirculation. Whether or not the sublingual microcirculation is impaired after noncardiac surgery remains a subject of ongoing research. Similarly, it remains unclear if cardiac surgery, especially with cardiopulmonary bypass, impairs the sublingual microcirculation. The effects of therapeutic interventions specifically targeting the microcirculation remain to be elucidated and tested. Future research should focus on further improving microcirculation monitoring methods and investigating how regional microcirculation monitoring can inform clinical decision-making and treatment.

Cross-sectional study of sublingual varicosities: systemic exposures.

PURPOSE: Sublingual varicose veins are a common vascular lesion with different names, such as caviar tongue or vascular malformations. This study aimed to investigate whether there is an association between sublingual varicose veins and cardiovascular diseases by observing arterial hypertension, diabetes, thrombosis, and infarction. In addition, to evaluate a series of thrombi that affected the oral cavity and to analyze their clinical aspects and relate them to possible systemic alterations. METHODS: This is a cross-sectional study consisting of a sample of 134 varicosities, 23 vascular malformations, and 4 thrombosis. RESULTS: Lingual varicosities are more frequently observed in women aged 57.4 ± 16.4 years. Hypertension was present in lingual varicosities (n = 73), as well as diabetes (n = 107), reports of thrombosis (n = 41), and infarction (n = 45). Arterial hypertension was decompensated (n = 12). The most frequent underlying diseases were diabetes (p < 0.001), infarction (p = 0.012), and thrombosis (p = 0.004), and the most commonly used drug was losartan. CONCLUSION: It can be inferred from the present study that lingual varicosities are related to cardiovascular diseases and can serve as a parameter to measure their decompensation.

Intraoperative intravenous infusion of lidocaine increases total and small vessel densities of sublingual microcirculation: a randomized prospective pilot study.

OBJECTIVE: Multiple organ failure can occur as a result of postoperative complications. Research has indicated that the underlying mechanism of organ dysfunction is a microcirculation disorder. Because of its antioxidant and anti-inflammatory properties, lidocaine has the potential to improve microvascular blood flow. This study was performed to assess the effect of intraoperative intravenous lidocaine infusion on the microcirculation and determine the incidence of postoperative complications. METHODS: In this prospective randomized double-blind pilot study, 12 patients scheduled for abdominal surgery were randomly allocated to receive an intraoperative infusion of either 1% lidocaine or the same volume of 0.9% sodium chloride solution. The microcirculation was monitored using sidestream dark-field imaging and the vascular occlusion test combined with near-infrared spectroscopy. RESULTS: Lidocaine significantly increased the total vascular density and small vessel density after 2 hours of infusion, with preservation of 99% to 100% of the capillary perfusion in both groups. No patients developed organ failure. CONCLUSIONS: An increase in vessel density may be beneficial in major abdominal surgeries because it is associated with better tissue perfusion and oxygen delivery. However, this finding requires further investigation in patients with increased surgical risk. Overall, this study indicates that lidocaine has potential to improve microvascular perfusion.Research Registry number: 9549 (https://www.researchregistry.com/browse-the-registry#home/registrationdetails/650ffd27b3f547002bd7635f/).

Hands Free Technique: New Tool Possibility for Image Capture of Sublingual Microcirculation with Handheld Vital Microscopy - HVM / Técnica de Manos Libres: Nueva Posibilidad de Herramienta para Capturar imágenes de Microcirculación Sublingual con Microscopía Vital Portátil ­ HVM

New microcirculatory imaging techniques allowed direct observation of microcirculation at the bedside. This study presents a new device that assists the operator with the unprecedented Hands Free technique. To this end, a replica of Handheld Vital Microscopy was developed to simulate the method of capturing the image in the sublingual area, the most used site to assess microcirculation in critically ill patients. We achieved a reduction in the displacement of micros cope replica with a Hands Free method. The immediate consequence is an increase in the stability of HVM replica by 75 times, or more, over the current 4 seconds, during its contact with the sublingual tissue. The device also offers better control of th e pressure of the tip of the HVM replica over the sublingual area. The results demonstrated that the Hands Free technique, operating in the same sublingual area for 900 seconds, should allow for future research aimed at therapeutic maneuvers in patients with serious illnesses.

Las nuevas técnicas de imagen microcirculatoria permitieron la observación directa de la microcirculación junto a la cama del paciente. Este estudio sin precedentes presenta un nuevo dispositivo que ayuda al operador con la técnica manos libres. Con este fin, se desarrolló una réplica de la Microscopía Vital Portátil para simular el método de captura de la imagen en el área sublingual, el sitio más utilizado para evaluar la microcirculación en pacientes críticos. Logramos una reducción en el desplazamiento de la réplica del microscopio con el método de manos libres. La consecuencia inmediata es un aumento en la estabilidad de la réplica de HVM en 75 veces, o más, durante los 4 segundos actuales, durante su contacto con el tejido sublingual. El dispositivo también ofrece un mejor control de la presión de la punta de la réplica de HVM sobre el área sublingual. Los resultados demostraron que la técnica de manos libres, que opera en la misma área sublingual durante 900 segundos, debería permitir futuras investigaciones destinadas a maniobras terapéuticas en pacientes con enfermedades graves.

Clinical Implications of the Submental and Sublingual Arteries in Relation to the Mylohyoid Boutonnière.

OBJECTIVE: Mylohyoid musculature may be included in the submental artery flap to protect perforators. However, blood vessels may pass through the mylohyoid muscle and therefore cause bleeding and risk to pedicle or perforator injury when a mylohyoid-containing flap is lifted. The objectives of this study were to identify the prevalence of the submental and sublingual arteries that traverse the mylohyoid and to assess relationships between vasculature transmitted through mylohyoid muscles and mylohyoid boutonnières. STUDY DESIGN: Cross-sectional human cadaveric study. SETTING: The West Virginia University School of Medicine human gross anatomic laboratories. SUBJECTS AND METHODS: A total of 43 intact mylohyoid muscles from 22 cadavers were dissected. The prevalence of submental vasculature perforating the mylohyoid was recorded in addition to the prevalence and contents of mylohyoid boutonnières. RESULTS: Of 43 mylohyoid muscles, 21 (48.8%) transmitted the submental or sublingual arteries, and 30 (69.1%) possessed boutonnières. One muscle had 2 boutonnières. Of 31 mylohyoid boutonnières, 21 transmitted blood vessels (67.7%). Specifically, 9 transmitted an artery and a vein (29.0%), and 12 transmitted an artery (38.7%). Ten boutonnières (32.3%) were exclusively occupied by fascia. CONCLUSION: This report identifies the importance of identifying and carefully ligating branches of the submental artery that pierce the mylohyoid during elevation of the submental island flap. This report also identifies that a boutonnière is often present where a submental or sublingual artery is traversing the mylohyoid to supply sublingual glands, tongue, and anterior mandible.

Assessment of the sublingual microcirculation with the GlycoCheck system: Reproducibility and examination conditions.

BACKGROUND: The glycocalyx is an extracellular layer lining the lumen of the vascular endothelium, protecting the endothelium from shear stress and atherosclerosis and contributes to coagulation, immune response and microvascular perfusion. The GlycoCheck system estimates glycocalyx' thickness in vessels under the tongue from perfused boundary region (PBR) and microvascular perfusion (red blood cell (RBC) filling) via a camera and dedicated software. OBJECTIVES: Evaluating reproducibility and influence of examination conditions on measurements with the GlycoCheck system. METHODS: Open, randomised, controlled study including 42 healthy smokers investigating day-to-day, side-of-tongue, inter-investigator variance, intraclass-correlation (ICC) and influence of examination conditions at intervals from 0-180 minutes on PBR and RBC filling. RESULTS: Mean (SD) age was 24.9 (6.1) years, 52% were male. There was no significant intra- or inter-investigator variation for PBR or RBC filling nor for PBR for side-of-tongue. A small day-to-day variance was found for PBR (0.012µm, p = 0.007) and RBC filling (0.003%, p = 0.005) and side-of-tongue, RBC filling (0.025%, p = 0.009). ICC was modest but highly improved by increasing measurements. Small significant influence of cigarette smoking (from 40-180 minutes), high calorie meal intake and coffee consumption was found. The latter two peaking immediately and tapering off but remained significant up to 180 minutes, highest PBR changes for the three being 0.042µm (p<0.05), 0.183µm (p<0.001) and 0.160µm (p<0.05) respectively. CONCLUSIONS: Measurements with the GlycoCheck system have a moderate reproducibility, but highly increases with multiple measurements and a small day-to-day variability. Smoking, meal and coffee intake had effects up to 180 minutes, abstinence is recommended at least 180 minutes before GlycoCheck measurements. Future studies should standardise conditions during measurements.

Automated Algorithm Analysis of Sublingual Microcirculation in an International Multicentral Database Identifies Alterations Associated With Disease and Mechanism of Resuscitation.

OBJECTIVES: Reliable automated handheld vital microscopy image sequence analysis and the identification of disease states and effects of therapy are prerequisites for the routine use of quantitative sublingual microcirculation measurements at the point-of-care. The present study aimed to clinically validate the recently introduced MicroTools software in a large multicentral database of perioperative and critically ill patients and to use this automatic algorithm to data-mine and identify the sublingual microcirculatory variable changes in response to disease and therapy. DESIGN: Retrospective algorithm-based image analysis and data-mining within a large international database of sublingual capillary microscopy. Algorithm-based analysis was compared with manual analysis for validation. Thereafter, MicroTools was used to identify the functional microcirculatory alterations associated with disease conditions and identify therapeutic options for recruiting functional microcirculatory variables. SETTING: Ten perioperative/ICU/volunteer studies in six international teaching hospitals. PATIENTS: The database encompass 267 adult and pediatric patients undergoing surgery, treatment for sepsis, and heart failure in the ICU and healthy volunteers. INTERVENTIONS: Perioperative and ICU standard of care. MEASUREMENTS AND MAIN RESULTS: One thousand five hundred twenty-five handheld vital microscopy image sequences containing 149,257 microscopy images were analyzed. 3.89 × 10 RBC positions were tracked by the algorithm in real time, and offline manual analysis was performed. Good correlation and trending ability were found between manual and automatic total and functional capillary density (r = 0.6-0.8; p < 0.0001). RBC tracking within the database demonstrated changes in functional capillary density and/or RBC velocity in septic shock, heart failure, hypovolemia, obstructive shock, and hemodilution and thus detected the presence of a disease condition. Therapies recruiting the microcirculatory diffusion and convection capacity associated with systemic vasodilation and an increase in cardiac output were separately identified. CONCLUSIONS: Algorithm-based analysis of the sublingual microcirculation closely matched manual analysis across a broad spectrum of populations. It successfully identified a methodology to quantify microcirculatory alterations associated with disease and the success of capillary recruitment, improving point-of-care application of microcirculatory-targeted resuscitation procedures.

Leukocyte-Endothelium Interaction in the Sublingual Microcirculation of Coronary Artery Bypass Grafting Patients.

OBJECTIVE: The aim of this study was to apply an innovative methodology to incident dark-field (IDF) imaging in coronary artery bypass grafting (CABG) patients for the identification and quantification of rolling leukocytes along the sublingual microcirculatory endothelium. METHODS: This study was a post hoc analysis of a prospective study that evaluated the perioperative course of the sublingual microcirculation in CABG patients. Video images were captured using IDF imaging following the induction of anesthesia (T0) and cardiopulmonary bypass (CPB) (T1) in 10 patients. Rolling leukocytes were identified and quantified using frame averaging, which is a technique that was developed for correctly identifying leukocytes. RESULTS: The number of rolling leukocytes increased significantly from T0 (7.5 [6.4-9.1] leukocytes/capillary-postcapillary venule/4 s) to T1 (14.8 [13.2-15.5] leukocytes/capillary-postcapillary venule/4 s) (p < 0.0001). A significant increase in systemic leukocyte count was also detected from 7.4 ± 0.9 × 109/L (preoperative) to 12.4 ± 4.4 × 109/L (postoperative) (p < 0.01). CONCLUSION: The ability to directly visualize leukocyte-endothelium interaction using IDF imaging facilitates the diagnosis of a systemic inflammatory response after CPB via the identification of rolling leukocytes. Integration of the frame averaging algorithm into the software of handheld vital microscopes may enable the use of microcirculatory leukocyte count as a real-time parameter at the bedside.

Large volume haemorrhage following transoral robotic surgery (TORS) as a result of fibromuscular dysplasia: first reported case.

We present a case of a 61-year-old woman who suffered a haemorrhagic complication of an aneurysmal left lingual artery, secondary to fibromuscular dysplasia, following transoral robotic surgery (TORS). She was admitted through the emergency department 3 days after resection of a central base of tongue tumour. She suffered a massive haemorrhage requiring intensive care admission, blood transfusion, intubation, operative and endovascular intervention. The diagnosis of fibromuscular dysplasia was made at angiography. During attempts to embolise the culprit left lingual artery, the vessel dissected at its origin leading to arrest of bleeding. Repeat angiograms during her admission demonstrated unchanged appearances and ruled out recanalisation of the vessel. She was extubated and remained stable on the ward, discharged home some days later in good health. To our knowledge, this is the first ever reported case of fibromuscular dysplasia affecting the lingual artery leading to aneurysmal dilation and severe haemorrhage following TORS.

Sublingual microcirculation: a case report.

INTRODUCTION: Sublingual microcirculation monitoring is suitable for bedside use in critically ill patients. We present a case in which severely impaired sublingual microcirculation was the first alarming sign of an early deterioration of the patient's medical situation. CASE PRESENTATION: This is the case of a 58-year-old white woman admitted to our intensive care unit after the removal of parts of her small intestine due to a volvulus. Her microcirculation was checked the day after surgery in terms of an ongoing study and predicted a massive deterioration of her clinical situation. CONCLUSIONS: This case highlights the potential value of monitoring the microcirculation in critically ill patients. Two full hours could have been saved for diagnostic workup and earlier treatment had we considered the impaired microcirculation alone as a warning sign. Regardless of the supposed cause, impaired microcirculation should alert the responsible physician and should be followed by a diagnostic workup. Sublingual microcirculation monitoring can be useful in intensive care units to detect a deteriorated microcirculation earlier than with standard monitoring.

Impact of advanced age on microvascular reconstruction of the lower facial third: An American College of Surgeons NSQIP study.

BACKGROUND: Microvascular reconstruction is the standard of care in head and neck reconstruction, though its perioperative safety in an older population has been controversial due to safety concerns, warranting further investigation. MATERIALS AND METHODS: An "older" (≥71 years) cohort undergoing reconstruction after mandibulectomy/glossectomy was compared to the remaining population in a National Surgical Quality Improvement Program (2008-2016) analysis. Cases required both a mandibulectomy/glossectomy and microvascular or local flap reconstruction (exclusion criteria: missing ages and simultaneous microvascular and local flap reconstruction). Demographics, comorbidities, and procedure types were analyzed on 985 patients (236 [24.4%] were ≥71). Outcomes were compared by reconstruction type. Regressions were performed calculating the impact of age on length of hospital stay (LOHS) and operative time. RESULTS: Ablative procedures were comparable, but older patients received local flaps at higher rates (22.5% vs. 9.6%; p < .001). The older population had more comorbidities (higher ASA class [p < .001], diabetes [p < .001], and hypertension [p < .001]). After Bonferroni correction, univariate subgroup analyses of soft tissue and bone/composite microvascular flaps revealed similar outcomes (except increased medical complications in the older cohort undergoing a bone free flap [p = .002]). Controlling for a variety of factors, older age resulted in longer LOHS (B: 1.4 days; 95% CI: 0.1-2.8 days; p = .035), but not operative time (B: -21.90 min; 95% CI: -52.76 to 8.96 min; p = .164). CONCLUSION: While increased age (≥70 years) was associated with a longer LOHS, complication rates were comparable. Although limited by the retrospective nature, evidence supports microvascular reconstruction in the elderly population with comparable outcomes.

Preload Dependence Is Associated with Reduced Sublingual Microcirculation during Major Abdominal Surgery.

BACKGROUND: Dynamic indices, such as pulse pressure variation, detect preload dependence and are used to predict fluid responsiveness. The behavior of sublingual microcirculation during preload dependence is unknown during major abdominal surgery. The purpose of this study was to test the hypothesis that during abdominal surgery, microvascular perfusion is impaired during preload dependence and recovers after fluid administration. METHODS: This prospective observational study included patients having major abdominal surgery. Pulse pressure variation was used to identify preload dependence. A fluid challenge was performed when pulse pressure variation was greater than 13%. Macrocirculation variables (mean arterial pressure, heart rate, stroke volume index, and pulse pressure variation) and sublingual microcirculation variables (perfused vessel density, microvascular flow index, proportion of perfused vessels, and flow heterogeneity index) were recorded every 10 min. RESULTS: In 17 patients, who contributed 32 preload dependence episodes, the occurrence of preload dependence during major abdominal surgery was associated with a decrease in mean arterial pressure (72 ± 9 vs. 83 ± 15 mmHg [mean ± SD]; P = 0.016) and stroke volume index (36 ± 8 vs. 43 ± 8 ml/m; P < 0.001) with a concomitant decrease in microvascular flow index (median [interquartile range], 2.33 [1.81, 2.75] vs. 2.84 [2.56, 2.88]; P = 0.009) and perfused vessel density (14.9 [12.0, 16.4] vs. 16.1 mm/mm [14.7, 21.4], P = 0.009), while heterogeneity index was increased from 0.2 (0.2, 0.4) to 0.5 (0.4, 0.7; P = 0.001). After fluid challenge, all microvascular parameters and the stroke volume index improved, while mean arterial pressure and heart rate remained unchanged. CONCLUSIONS: Preload dependence was associated with reduced sublingual microcirculation during major abdominal surgery. Fluid administration successfully restored microvascular perfusion.

Reproducibility of sublingual microcirculation parameters obtained from sidestream darkfield imaging.

BACKGROUND: Changes in the microcirculation may be used as a surrogate outcome in studies on cardiovascular disease. We assessed the reliability characteristics of the sublingual microcirculation parameters Vascular Density (VD), Red Blood Cell Filling (RBCF), and Perfused Boundary Region (PBR) as obtained by sidestream darkfield imaging. METHODS: For each of the three parameters, the variance components of measurement, the Intraclass Correlation Coefficient (ICC), the Standard Error of Measurement, and the limits of agreement were estimated for the intra-rater setting (N = 50) and the inter-rater setting (N = 48). Subsequently, as a proof of concept, the reliability measures were used for a power analysis to design studies to evaluate the effect of acute stimuli-i.e. having a meal (N = 50) and cigarette smoking (N = 21) on the three parameters. RESULTS: Reproducibility was poor for all three parameters. The intra-rater ICC for 2 measurements was 0.28 (95% CI: 0.04, 0.53) for the VD, 0.51 (95% CI: 0.27, 0.69) for the RBCF, and 0.33 (95% CI: 0.08-0.56) for the PBR. The standard errors of measurement and the limits of agreement for all three parameters were larger than most statistically significant intra-individual or inter-individual differences reported in previous studies. The proofs of concept showed that sample sizes in excess of 600 subjects are necessary to reach statistical significance for the observed effects of having a meal or smoking on VD and PBR. CONCLUSIONS: The reliability of the three sublingual microcirculation parameters in their current form appears to be low and a large sample size is advisable for their use in conditions similar to those we describe.

Sublingual microcirculation in pancreatico-biliary surgery: An observational study.

BACKGROUND: An observational cohort study was conducted to identify potential sublingual microcirculation parameters as a target for goal-directed fluid therapy. METHODS: Patients that were scheduled for an open elective pancreatico-biliary surgery in Erasmus Medical Center were included. All patients underwent sublingual microcirculatory measurement at three time points: one day before surgery (T0), within the first 24 hours after surgery (T1) and on the fourth day after surgery (T2). The following parameters were obtained: microvascular flow index (MFI (AU)), Total vessels density (TVD (mm/mm2/)), Perfused vessels density (PVD (mm/mm2)), and proportion of perfused vessels (PPV (%)). RESULTS: Sixteen patients were included in the final analysis. The differences between the time points T1 and T0 in patients without clinical significant complication and in patients with these complications gave a significant difference for PVD small vessels (PVDs) (delta PVDs mean -0.1 vs -8.2, p=0.01) and PPV small vessels (PPVs) (delta PPVs median 7.0 % vs -15.5 %, p=0.01). CONCLUSION: The most significant microcirculatory parameter for a perioperative complicated course is the change of PVD and PPV. In the first 24 hours after surgery, if these parameters decrease there is a high chance of a complicated perioperative course.

Changes in the sublingual microcirculation following aortic surgery under balanced or total intravenous anaesthesia: a prospective observational study.

BACKGROUND: In vascular surgery with aortic cross-clamping, ischemia/reperfusion injury induces systemic haemodynamic and microcirculatory disturbances. Different anaesthetic regimens may have a varying impact on tissue perfusion. The aim of this study was to explore changes in microvascular perfusion in patients undergoing elective open abdominal aortic aneurysm repair under balanced or total intravenous anaesthesia. METHODS: Prospective observational study. Patients undergoing elective open infrarenal abdominal aortic aneurysm repair received balanced (desflurane + remifentanil, n = 20) or total intravenous anaesthesia (TIVA, propofol + remifentanil using target-controlled infusion, n = 20) according to the clinician's decision. A goal-directed haemodynamic management was applied in all patients. Measurements were obtained before anaesthesia induction (baseline) and at end-surgery and included haemodynamics, arterial/venous blood gases, sublingual microvascular flow and density (incident dark field illumination imaging), peripheral muscle tissue oxygenation and microcirculatory reactivity (thenar near infrared spectroscopy with a vascular occlusion test). RESULTS: The two groups did not differ for baseline characteristics, mean aortic-clamping time and requirement of vasoactive agents during surgery. Changes in mean arterial pressure, systemic vascular resistance index, haemoglobin and blood lactate levels were similar between the two groups, while the cardiac index increased at end-surgery in patients undergoing balanced anaesthesia. The sublingual microcirculation was globally unaltered in the TIVA group at end-surgery, while patients undergoing balanced anaesthesia showed an increase in the total and perfused small vessel densities (from 16.6 ± 4.2 to 19.1 ± 5.4 mm/mm2, p < 0.05). Changes in microvascular density were negatively correlated with changes in the systemic vascular resistance index. The area of reactive hyperaemia during the VOT increased in the balanced anaesthesia group (from 14.8 ± 8.1 to 25.6 ± 14.8%*min, p < 0.05). At end-surgery, the tissue haemoglobin index in the TIVA group was lower than that in the balanced anaesthesia group. CONCLUSIONS: In patients undergoing elective open abdominal aortic aneurysm repair with a goal-directed hemodynamic management, indices of sublingual or peripheral microvascular perfusion/oxygenation were globally preserved with both balanced anaesthesia and TIVA. Patients undergoing balanced anaesthesia showed microvascular recruitment at end-surgery. TRIAL REGISTRATION: NCT03510793 , https://www.clinicaltrials.gov, date of registration April 27th 2018, retrospectively registered.

Effect of Dexmedetomidine Infusion on Sublingual Microcirculation in Patients Undergoing On-Pump Coronary Artery Bypass Graft Surgery: A Prospective Randomized Trial.

OBJECTIVES: Cardiac surgery is characterized by attenuation of microcirculatory perfusion. Dexmedetomidine has been proved to attenuate the microcirculatory derangements evoked by experimental sepsis. The authors investigated the effects of dexmedetomidine infusion on sublingual microcirculation in patients undergoing on-pump coronary artery bypass graft (CABG) surgery. DESIGN: Prospective, randomized blinded study. SETTINGS: Tertiary university hospital. PARTICIPANTS: A total of 70 adults undergoing elective on-pump CABG surgery. INTERVENTION: After a standard general anesthesia, participants were allocated randomly to receive either propofol continuous intravenous infusion, 50 to 70 µg/kg/min, or propofol infusion, 50 to 70 µg/kg/min plus dexmedetomidine infusion, 0.5 µg/kg/h, during cardiopulmonary bypass. Microcirculation was studied with side-stream dark field imaging at 3 times: immediately before starting bypass (T0), 30 minutes after initiation of bypass (T1), and 30 minutes after weaning from bypass (T2). MEASUREMENTS AND MAIN RESULTS: Microvascular flow index was significantly higher in the dexmedetomidine group at T2 compared to the control group (2.20 ± 0.29 and 1.47 ± 0.30, respectively; p = 0.001). The perfused vessel density was significantly higher in the dexmedetomidine group at T2 compared to the control group (6.1 [3-8.9] mm/mm² and 3.3 [2.2-4.3] mm/mm², respectively; p = 0.01). The total vascular density was significantly higher in the dexmedetomidine group compared to the control group at T1 and T2 (9.9 [7.8-12.6] mm/mm² v 7.4 [6.1-9] mm/mm², p = 0.005; and 9.27 ± 2.27 mm/mm² v 7.24 ± 1.66 mm/mm², p = 0.003, respectively). CONCLUSION: This trial demonstrated that dexmedetomidine infusion improved sublingual microcirculation indices in patients undergoing on-pump CABG surgery.

Impact of mean arterial pressure on sublingual microcirculation during cardiopulmonary bypass-Secondary outcome from a randomized clinical trial.

OBJECTIVE: In this substudy of a randomized, clinical trial, we explored the sublingual microcirculation during cardiac surgery at 2 different levels of blood pressure. We hypothesized that a higher map during CPB would cause higher MFI. METHODS: Thirty-six cardiac surgery patients undergoing CABG were included and randomized to either low (40-50 mm Hg) or high (70-80 mm Hg) MAP during CPB. SDF video images were recorded from the sublingual mucosa. Recordings were analyzed in a blinded fashion to quantify microcirculatory variables. RESULTS: MAP during CPB in the low target group was 45.0 mm Hg (SD: 5.3) vs 67.2 mm Hg (SD: 8.9) in the high target group. We found no significant difference between the 2 groups in MFI during CPB evaluated for AV: 2.91 vs 2.90 (P = .82). For sm AV (<20 µm), the corresponding values were 2.87 and 2.85 in the low and high target groups, respectively (P = .82). CONCLUSIONS: We found no significant difference in sublingual microcirculatory flow expressed as MFI according to 2 different levels of MAP during CPB.

Sublingual microcirculatory alterations in cirrhotic patients.

OBJECTIVE: To assess sublingual microcirculation in cirrhotic patients and its relationship to spider angiomas, complications, and outcome. METHODS: Thirty-one cirrhotic patients were prospectively compared to 31 matched controls. Sublingual microcirculation was evaluated by videomicroscopy. We specifically looked for capillaries with increased RBCV, which was defined as a velocity higher than the percentile 100th of controls. RESULTS: Compared to controls, cirrhotic patients showed decreased total and PVD (14.4 ± 2.2 vs 16.0 ± 1.3 and 14.1 ± 2.3 vs 15.9 ± 1.6 mm/mm2 , respectively, P < .001 for both) and increased HFI (0.64 ± 0.39 vs 0.36 ± 0.21, P = .001). They also exhibited high RBCV in 2% of the microvessels (P < .0001). Patients with MELD score ≥10 had higher RBCV than patients with score <10 (1414 ± 290 vs 1206 ± 239 µm/s, P < .05). Patients with spider angiomas showed lower vascular densities. Microcirculation did not differ between survivors and nonsurvivors. CONCLUSIONS: Cirrhosis is associated with microcirculatory alterations that can be easily monitored in the sublingual mucosa. Alterations included decreased density and PPV and hyperdynamic microvessels. The most striking finding, however, was the microvascular heterogeneity. Patients with spider angiomas had more severe alterations. Larger studies should clarify the relationship between microcirculatory abnormalities and outcome.