Point­of­Care Ultrasound - accuracy, education.

A review article discussing the reliability of Point-of-Care ultrasound and education in this method in various fields of medicine.

Statement of the Expert Discussion Panel of the 1st Expert Conference on Point­of­Care ultrasound.

The document summarizes the statement of the expert discussion panel of the 1st Point- of-Care Ultrasonography, which took place on 14 November 2022 in Prague and which led to the foundation of the Czech Multidisciplinary Task Force Group for standards,education and research in Point-of-Care ultrasound (Czech POCUS group).

Correlation between end-tidal carbon dioxide and the degree of compression of heart cavities measured by transthoracic echocardiography during cardiopulmonary resuscitation for out-of-hospital cardiac arrest.

BACKGROUND: The concept of personalized cardiopulmonary resuscitation (CPR) requires a parameter that reflects its hemodynamic efficiency. While intra-arrest ultrasound is increasingly implemented into the advanced life support, we realized a pre-hospital clinical study to evaluate whether the degree of compression of the right ventricle (RV) and left ventricle (LV) induced by chest compressions during CPR for out-of-hospital cardiac arrest (OHCA) and measured by transthoracic echocardiography correlates with the levels of end-tidal carbon dioxide (EtCO2) measured at the time of echocardiographic investigation. METHODS: Thirty consecutive patients resuscitated for OHCA were included in the study. Transthoracic echocardiography was performed from a subcostal view during ongoing chest compressions in all of them. This was repeated three times during CPR in each patient, and EtCO2 levels were registered. From each investigation, a video loop was recorded. Afterwards, maximal and minimal diameters of LV and RV were obtained from the recorded loops and the compression index of LV (LVCI) and RV (RVCI) was calculated as (maximal - minimal/maximal diameter) × 100. Maximal compression index (CImax) defined as the value of LVCI or RVCI, whichever was greater was also assessed. Correlations between EtCO2 and LVCI, RVCI, and CImax were expressed as Spearman's correlation coefficient (r). RESULTS: Evaluable echocardiographic records were found in 18 patients, and a total of 52 measurements of all parameters were obtained. Chest compressions induced significant compressions of all observed cardiac cavities (LVCI = 20.6 ± 13.8%, RVCI = 34.5 ± 21.6%, CImax = 37.4 ± 20.2%). We identified positive correlation of EtCO2 with LVCI (r = 0.672, p < 0.001) and RVCI (r = 0.778, p < 0.001). The strongest correlation was between EtCO2 and CImax (r = 0.859, p < 0.001). We identified that a CImax cut-off level of 17.35% predicted to reach an EtCO2 level > 20 mmHg with 100% sensitivity and specificity. CONCLUSIONS: Evaluable echocardiographic records were reached in most of the patients. EtCO2 positively correlated with all parameters under consideration, while the strongest correlation was found between CImax and EtCO2. Therefore, CImax is a candidate parameter for the guidance of hemodynamic-directed CPR. TRIAL REGISTRATION: ClinicalTrial.gov, NCT03852225 . Registered 21 February 2019 - Retrospectively registered.

Comparison of cold crystalloid and colloid infusions for induction of therapeutic hypothermia in a porcine model of cardiac arrest.

INTRODUCTION: Large-volume cold intravenous infusion of crystalloids has been used for induction of therapeutic hypothermia after cardiac arrest. However, the effectiveness of cold colloids has not been evaluated. Therefore, we performed an experimental study to investigate the cooling effect of cold normal saline compared to colloid solution in a porcine model of ventricular fibrillation. METHODS: Ventricular fibrillation was induced for 15 minutes in 22 anesthetized domestic pigs. After spontaneous circulation was restored, the animals were randomized to receive either 45 ml/kg of 1°C cold normal saline (Group A, 9 animals); or 45 ml/kg of 1°C cold colloid solution (Voluven, 6% hydroxyethyl starch 130/0.4 in 0.9% NaCl) during 20 minutes (Group B, 9 animals); or to undergo no cooling intervention (Group C, 4 animals). Then, the animals were observed for 90 minutes. Cerebral, rectal, intramuscular, pulmonary artery, and subcutaneous fat body temperatures (BT) were recorded. In the mechanical ex-vivo sub study we added a same amount of cold normal saline or colloid into the bath of normal saline and calculated the area under the curve (AUC) for induced temperature changes. RESULTS: Animals treated with cold fluids achieved a significant decrease of BT at all measurement sites, whereas there was a consistent significant spontaneous increase in group C. At the time of completion of infusion, greater decrease in pulmonary artery BT and cerebral BT in group A compared to group B was detected (-2.1 ± 0.3 vs. -1.6 ± 0.2°C, and -1.7 ± 0.4 vs. -1.1 ± 0.3°C, p < 0.05, respectively). AUC analysis of the decrease of cerebral BT revealed a more vigorous cooling effect in group A compared to group B (-91 ± 22 vs. -68 ± 23°C/min, p = 0.046). In the mechanical sub study, AUC analysis of the induced temperature decrease of cooled solution revealed that addition of normal saline led to more intense cooling than colloid solution (-7155 ± 647 vs. -5733 ± 636°C/min, p = 0.008). CONCLUSIONS: Intravenous infusion of cold normal saline resulted in more intense decrease of cerebral and pulmonary artery BT than colloid infusion in this porcine model of cardiac arrest. This difference is at least partially related to the various specific heat capacities of the coolants.

Shock Index for Early Detection of Low Plasma Fibrinogen in Trauma: A Prospective Observational Cohort Pilot Study.

Shock index (a ratio between heart rate and systolic blood pressure) predicts transfusion requirements and the need for haemostatic resuscitation in severe trauma patients. In the present study, we aimed to determine whether prehospital and on-admission shock index values can be used to predict low plasma fibrinogen in trauma patients. Between January 2016 and February 2017, trauma patients admitted from the helicopter emergency medical service into two large trauma centres in the Czech Republic were prospectively assessed for demographic, laboratory and trauma-associated variables and shock index at scene, during transport and at admission to the emergency department. Hypofibrinogenemia defined as fibrinogen plasma level of 1.5 g·L-l was deemed as a cut-off for further analysis. Three hundred and twenty-two patients were screened for eligibility. Of these, 264 (83%) were included for further analysis. The hypofibrinogenemia was predicted by the worst prehospital shock index with the area under the receiver operating characteristics curve (AUROC) of 0.79 (95% CI 0.64-0.91) and by the admission shock index with AUROC of 0.79 (95% CI 0.66-0.91). For predicting hypofibrinogenemia, the prehospital shock index ≥ 1 has 0.5 sensitivity (95% CI 0.19-0.81), 0.88 specificity (95% CI 0.83-0.92) and a negative predictive value of 0.98 (0.96-0.99). The shock index may help to identify trauma patients at risk of hypofibrinogenemia early in the prehospital course.

Protection of the endothelium and endothelial glycocalyx by hydrogen against ischaemia-reperfusion injury in a porcine model of cardiac arrest.

BACKGROUND: Hydrogen is a potent antioxidant agent that can easily be administered by inhalation. The aim of the study was to evaluate whether hydrogen protects the endothelial glycocalyx layer after successful cardiopulmonary resuscitation (CPR). METHODS: Fourteen anesthetized pigs underwent CPR after induced ventricular fibrillation. During CPR and return of spontaneous circulation, 2% hydrogen gas was administered to seven pigs (hydrogen group) and seven constituted a control group. Biochemistry and sublingual microcirculation were assessed at baseline, during CPR, at the 15th, 30th, 60th, 120th minute. RESULTS: All seven subjects from the hydrogen group and six subjects in the control group were successfully resuscitated after 6-10 minutes. At baseline, there were no statistically significant differences in examined variables. After the CPR, blood pH, base excess, and lactate showed significantly smaller deterioration in the hydrogen group than in the control group. By contrast, plasma syndecan-1 and the measured variables obtained via sublingual microcirculation did not change after the CPR; and were virtually identical between the two groups. CONCLUSION: In pigs, hydrogen gas inhalation during CPR and post-resuscitation care was associated with less pronounced metabolic acidosis compared to controls. However, we could not find evidence of injury to the endothelium or glycocalyx in any studied groups.

Virtual histology evaluation of atherosclerosis regression during atorvastatin and ezetimibe administration: HEAVEN study.

BACKGROUND: There is no study focusing on changes in coronary atherosclerosis during dual lipid-lowering therapy with statin and ezetimibe. METHODS AND RESULTS: Eighty-nine patients with stable angina randomized in a 1:1 ratio to Group A (aggressive therapy: atorvastatin 80mg, ezetimibe 10mg) and Group S (standard therapy) were analyzed. Treatment period was 12 months. Coronary arteries were examined by intravascular ultrasound and virtual histology. We found a decrease in the percent atheroma volume (PAV) (-0.4%) in Group A compared with an increase (+1.4%) in Group S (P=0.014) and this was accompanied by an increased frequency of combined atherosclerosis regression (increased lumen volume+decreased PAV) in group A (40.5%) compared with group S (14.9%) (P=0.007). The target low-density lipoprotein cholesterol level <2mmol/L, presence of at least 4 of 5 atherosclerotic risk factors, and decreased level of vascular cellular adhesive molecule were independent predictors of plaque regression. There were no significant differences in plaque composition between the 2 groups over the study duration. However, during analysis of the 2 groups together, fibrous and fibro-fatty tissues decreased and dense calcification and necrotic core increased during follow-up. CONCLUSIONS: Dual lipid-lowering therapy starts atherosclerosis regression, but does not lead to significant changes in plaque composition. The continuous shift in plaque from fibro and fibro-fatty to necrotic with calcification was present in both groups.

Fixed-dose enoxaparin provides efficient DVT prophylaxis in mixed ICU patients despite low anti-Xa levels: A prospective observational cohort study.

BACKGROUND: Deep vein thrombosis (DVT) is a serious but preventable complication of critical illness with a reported incidence from 4 to 17%. Anti-Xa activity in critically ill patients achieved with standard dosing of low-molecular-weight heparins (LMWH) is often below the target of 0.2-0.5 IU/mL. However, the clinical significance of this finding is unclear. The quality of thromboprophylaxis also strongly impacts the incidence of DVT. We performed a prospective observational study to evaluate the incidence of DVT in a mixed medical-surgical-trauma intensive care unit (ICU) using a thromboprophylaxis protocol with a fixed dose of enoxaparin. We also explored the relation between DVT incidence and anti-Xa activity. METHOD: All consecutive patients with expected ICU stay ≥72 hours and without evidence of DVT upon admission were included. They underwent ultrasound screening for DVT twice a week until ICU discharge, death, DVT or pulmonary embolism. Peak anti-Xa activity was measured twice a week. Patients received 40 mg of enoxaparin subcutaneously (60 mg in obese, 20 mg in case of renal failure). Graduated compression stockings were used in case of LMWH or another anticoagulant contraindication. RESULTS: A total of 219 patients were enrolled. We observed six cases of DVT (incidence of 2.7%). The agreement between expected and delivered DVT prophylaxis was 94%. Mean peak anti-Xa activity level was 0.24 (SD, 0.13) IU/mL. There was no significant difference in anti-Xa activity in DVT and non-DVT group. CONCLUSION: A low incidence of DVT was achieved with meticulous adherence to the standard prophylactic protocol. The low incidence of DVT was observed despite low levels of anti-Xa activity. Our findings suggest that enoxaparin dose adjustment based on regular monitoring of anti-Xa activity is unlikely to result in further reduction of DVT incidence in a mixed ICU population. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03286985.

No significant retinal damage induced by major orthopedic surgery - a pilot study.

BACKGROUND: Perioperative visual loss is one of the rare but devastating complications of anesthesia and surgery. The incidence of less severe or even subclinical postoperative visual dysfunction is unknown. Therefore, we decided to perform a pilot prospective observational clinical study to evaluate whether structural changes of the retina can be detected in patients undergoing elective orthopaedic surgery by optical coherence tomography (OCT). METHODS: Adult patients indicated for elective knee replacement surgery with the absence of known retinal or optic nerve disease were included. Each patient underwent baseline OCT examination of the eyes one day before surgery and it was repeated 4-7 days after the surgery. The surgery was done under general and epidural anesthesia. RESULTS: A total of 18 patients (6 men and 12 women) at the age of 70.8±7.1 years were enrolled. We found statistically significant changes in the Macular central thickness and in a few areas of the Retinal Nerve Fiber Layer between the baseline and postoperative measurements. CONCLUSIONS: Even though we found significant changes in some parameters, we did not confirm that general anesthesia and/or surgical damage causes significant damage of the retina using OCT measurement. TRIAL REGISTRATION: ClinicalTrials.gov (NCT04311801).

Endothelial glycocalyx damage in patients with severe COVID-19 on mechanical ventilation - A prospective observational pilot study.

BACKGROUND: Coronavirus disease (COVID-19) associated endotheliopathy and microvascular dysfunction are of concern. OBJECTIVE: The objective of the present single-center observational pilot study was to compare endothelial glycocalyx (EG) damage and endotheliopathy in patients with severe COVID-19 (COVID-19 group) with patients with bacterial pneumonia with septic shock (non-COVID group). METHODS: Biomarkers of EG damage (syndecan-1), endothelial cells (EC) damage (thrombomodulin), and activation (P-selectin) were measured in blood on three consecutive days from admission to the intensive care unit (ICU). The sublingual microcirculation was studied by Side-stream Dark Field (SDF) imaging with automatic assessment. RESULTS: We enrolled 13 patients in the non-COVID group (mean age 70 years, 6 women), and 15 in the COVID-19 group (64 years old, 3 women). The plasma concentrations of syndecan-1 were significantly higher in the COVID-19 group during all three days. Differences regarding other biomarkers were not statistically significant. The assessment of the sublingual microcirculation showed improvement on Day 2 in the COVID-19 group. Plasma levels of C-reactive protein (CRP) were significantly higher on the first two days in the COVID-19 group. Plasma syndecan-1 and CRP were higher in patients suffering from severe COVID-19 pneumonia compared to bacterial pneumonia patients. CONCLUSIONS: These findings support the role of EG injury in the microvascular dysfunction in COVID-19 patients who require ICU.

Long-term prognostic impact of hyponatremia in the ST-elevation myocardial infarction.

AIMS: The aim of the study was to analyse in-hospital outcomes and long-term prognostic implications of reduced sodium serum level (S-Na) in the early phase of ST elevation myocardial infarction (STEMI) treated, primarily, with direct percutaneous coronary intervention (dPCI). METHODS AND RESULTS: The study included 218 consecutive patients (144 males, the mean age 64 ± 13 years) with no history of heart failure admitted with acute STEMI. Out of them, 193 (88.5%) patients were treated with dPCI. The mean follow-up period was 39 ± 21 months. Hyponatremia was defined as S-Na value < 135 mmol/L. A total of 72 (33%) patients reached hyponatremia level; 51(23.4%) of them at admission and 21 (9.6%) later during hospitalization. The hyponatremic patients more frequently presented with reduced left ventricular systolic function, Killip class III or IV and were at increased risk of developing cardiogenic shock compared to patients with normonatremia. Compared to the rest of the population, patients who developed hyponatremia later during hospitalization had higher incidence of acute renal failure; (12 patients/6.1% vs. 5 patients/25.5%, p < 0.05). The difference in long-term survival between the hyponatremia and normonatremia groups was significant (p = 0.01, log-rank test). The multiple analysis of variance identified decrease of S-Na levels at admission independently associated with total mortality (p = 0.05). CONCLUSION: Patients who developed hyponatremia in the early phase of STEMI were at higher risk of worse in-hospital clinical outcome. During the long-term follow-up, higher mortality rates were recorded in hyponatremic patients.

Prehospital cooling by cold infusion: searching for the optimal infusion regimen.

BACKGROUND: The cooling efficacy of intravenous administration of cold crystalloids can be enhanced by optimisation of the procedure. This study assessed the temperature stability of different application regimens of cold normal saline (NS) in simulated prehospital conditions. METHODS: Twelve different application regimens of 4 °C cold NS (volumes of 250, 500 and 1000 ml applied at infusion rates of 1000, 2000, 4000 and 6000 ml/h) were investigated for infusion temperature changes during administration to an artificial detention reservoir in simulated prehospital conditions. RESULTS: An increase in infusion temperature was observed in all regimens, with an average of 8.1 ± 3.3 °C (p<0.001). This was most intense during application of the residual 20% of the initial volume. The lowest rewarming was exhibited in regimens with 250 and 500 ml bags applied at an infusion rate of 6000 ml/h and 250 ml applied at 4000 ml/h. More intense, but clinically acceptable, rewarming presented in regimens with 500 and 1000 ml bags administered at 4000 ml/h, 1000 ml at 6000 ml/h and 250 ml applied at 2000 ml/h. Other regimens were burdened by excessive rewarming. CONCLUSION: Rewarming of cold NS during application in prehospital conditions is a typical occurrence. Considering that the use of 250 ml bags means the infusion must be exchanged too frequently during cooling, the use of 500 or 1000 ml NS bags applied at an infusion rate of ≥4000 ml/h and termination of the infusion when 80% of the infusion volume has been administered is regarded as optimal.

Lung Point Sign in Ultrasound Diagnostics of Pneumothorax: Imitations and Variants.

BACKGROUND: Pulmonary ultrasound plays a key role in the diagnosis of pneumothorax in emergency and intensive-care medicine. The lung point sign has been generally considered a pathognomonic diagnostic sign. Recently, several other situations have been published that can mimic the lung point, as well as a few different variants of the true lung point sign. MATERIALS AND METHODS: Based on years of monitoring the literature and collecting our database of ultrasound findings, we prepared a review of ultrasound findings mimicking the lung point sign and ultrasound variants of the true lung point sign. RESULTS: We present four imitations of the lung point sign (physiological lung point sign, pseudo-lung point sign, bleb point sign, and pleurofascial point sign) and two variants of the true lung point sign (double lung point sign and hydro point sign) documented by images and video records. CONCLUSIONS: Knowledge of ultrasound imitations and variants of the lung point sign may increase the reliability of pneumothorax diagnosis and may reduce the risk of performing unindicated interventions.

Successful treatment of refractory status asthmaticus with omalizumab: a case report.

Refractory status asthmaticus is the cause of rare cases of in-hospital death due to acute bronchial asthma. The most severe cases unresponsive to first, second and next line treatment may be fatal despite aggressive organ support with invasive ventilation and extracorporeal membrane oxygenation. Omalizumab, a humanized recombinant monoclonal anti-IgE antibody, is an approved add-on biological treatment for severe asthma. However, it is not indicated in an acute setting. Here, we report the case of a young patient with status asthmaticus fully dependent on extracorporeal membrane oxygenation refractory to any therapy for six days, who was successfully treated with omalizumab.

Subcostal TAPSE measured by anatomical M-mode: prospective reliability clinical study in critically ill patients.

BACKGROUND: Tricuspid annular plane systolic excursion (TAPSE), evaluated from a four-chamber apical view, is an echocardiographic parameter for the detection of right ventricular systolic dysfunction (RVD). We decided to assess the reliability of TAPSE measured from subcostal view (sTAPSE) by anatomical M-mode imaging (AMM) for evaluation of right ventricular systolic function and prediction of RVD in the critically ill patients by comparison with other echocardiographic parameters. METHODS: We conducted an observational, prospective clinical study in 100 patients hospitalized in the intensive care unit. TAPSE, doppler tissue imaging-derived tricuspid lateral annular systolic velocity (DTI-S' wave), two-dimensional fraction area change (2D FAC) and DTI-right ventricular index of myocardial performance (DTI-RIMP) were measured by transthoracic echocardiography. A subcostal four-chamber view was recorded for sTAPSE measurement. For that purpose, the cursor of AMM was aligned along the direction of the tricuspid lateral annulus movement and the amplitude of the movement was measured. RESULTS: In a group of patients aged 64±16 years with a 31% prevalence of RVD we identified strong correlation between TAPSE and sTAPSE (r=0.963, P<0.001). sTAPSE correlated well with other measures of right ventricular systolic function (DTI-S' wave: r=0.765; 2D FAC: r=0.701; DTI-RIMP: r=-0.661, P<0.001, respectively). The value of sTAPSE ≤15 mm predicted the presence of RVD defined by TAPSE with a sensitivity of 94.7% and specificity of 100.0%. CONCLUSIONS: The sTAPSE measured by AMM in a population of critically ill patients has been found to be a reliable parameter of right ventricular systolic function and predicted RVD with high reliability.

Pre-hospital cooling of patients following cardiac arrest is effective using even low volumes of cold saline.

INTRODUCTION: Pre-hospital induction of therapeutic mild hypothermia (TH) may reduce post-cardiac arrest brain injury in patients resuscitated from out-of-hospital cardiac arrest. Most often, it is induced by a rapid intravenous administration of as much as 30 ml/kg of cold crystalloids. We decided to assess the pre-hospital cooling effectivity of this approach by using a target dose of 15-20 ml/kg of 4°C cold normal saline in the setting of the physician-staffed Emergency Medical Service. The safety and impact on the clinical outcome have also been analyzed. METHODS: We performed a prospective observational study with a retrospective control group. A total of 40 patients were cooled by an intravenous administration of 15-20 ml/kg of 4°C cold normal saline during transport to the hospital (TH group). The pre-hospital decrease of tympanic temperature (TT) was analyzed as the primary endpoint. Patients in the control group did not undergo any pre-hospital cooling. RESULTS: In the TH group, administration of 12.6 ± 6.4 ml/kg of 4°C cold normal saline was followed by a pre-hospital decrease of TT of 1.4 ± 0.8°C in 42.8 ± 19.6 min (p < 0.001). The most effective cooling was associated with a transport time duration of 38-60 min and with an infusion of 17 ml/kg of cold saline. In the TH group, a trend toward a reduced need for catecholamines during transport was detected (35.0 vs. 52.5%, p = 0.115). There were no differences in demographic variables, comorbidities, parameters of the cardiopulmonary resuscitation and in other post-resuscitation characteristics. The coupling of pre-hospital cooling with subsequent in-hospital TH predicted a favorable neurological outcome at hospital discharge (OR 4.1, CI95% 1.1-18.2, p = 0.046). CONCLUSIONS: Pre-hospital induction of TH by the rapid intravenous administration of cold normal saline has been shown to be efficient even with a lower dose of coolant than reported in previous studies. This dose can be associated with a favorable impact on circulatory stability early after the return of spontaneous circulation and, when coupled with in-hospital continuation of cooling, can potentially improve the prognosis of patients. TRIAL REGISTRATION: ClinicalTrials (NCT): NCT00915421.

Two different techniques of ultrasound-guided peripheral venous catheter placement versus the traditional approach in the pre-hospital emergency setting: a randomized study.

We performed a randomized pre-hospital clinical study to compare two different techniques of ultrasound-guided peripheral venous catheter (PVC) insertion and the conventional cannulation technique in the pre-hospital emergency setting, with a specific focus on the procedural success rate and the time required to introduce PVC. This pre-hospital prospective controlled randomized clinical trial allocated patients treated by emergency medical service to undergo PVC insertion fully controlled by ultrasound (ultrasound guidance of the PVC tip until it penetrates the lumen, group A), PVC insertion partially controlled by ultrasound (target vein identification only, group B) or to receive PVC without any ultrasound guidance (group C). The study outcomes were monitored until the patient was admitted to the hospital. A total of 300 adult patients were enrolled. The success of the first attempt (group A: 88%, group B: 94%, group C: 76%, p < 0.001) and overall success rate (A: 99%, B: 99%, C: 90%, p < 0.001) were significantly higher in the group A, followed by group B when compared to group C. The number of attempts was significantly lower (A: 1.18 ± 0.54, B: 1.05 ± 0.22, C: 1.22 ± 0.57, p < 0.001) and the time required for the procedure shorter (A: 75.3 ± 60.6, B: 43.5 ± 26.0, C: 82.3 ± 100.9 s, p < 0.001) in group B compared to groups A and C. Both techniques of ultrasound-guided PVC placement were associated with higher success rates than the conventional method. However, PVC insertion partially controlled by ultrasound was superior to full ultrasound guidance in terms of time and number of cannulation attempts required.

Variability of aortic blood flow predicts fluid responsiveness in spontaneously breathing healthy volunteers.

BACKGROUND: Assessment of fluid responsiveness is an important topic in acute cardiology. Echocardiographic measurement of respiratory variations of aortic blood velocity in ventilated shock patients can accurately predict the effect of volume expansion. On the other hand, it remains unclear whether this respiratory variability is a common physiological reaction to hypovolaemia and whether its measurement is applicable also in spontaneously breathing patients. AIM: To assess whether respiratory variability of peak aortic blood flow velocity (DVpeakao) and of aortic velocity time integral (DVTIao) reflects preload-dependent changes of cardiac index (CI) and whether it predicts fluid responsiveness in healthy spontaneously breathing volunteers. METHODS: DVpeakao, DVTIao and CI were measured by transthoracic echocardiography in 20 volunteers at baseline and after intravenous administration of furosemide (0.5 mg/kg). Afterwards, volunteers were randomised to rapid intravenous volume expansion (group A) or no expansion (group B) and assessed finally. RESULTS: Hypovolaemia induction was associated with a decrease of CI (from 3.25 +/- 0.50 to 2.28 +/- 0.43 l/min/m2, p < 0.001) which correlated with an increase of DVpeakao (r = -0.490, p = 0.028) and DVTIao (r = -0.554, p = 0.011) in both groups. In group A, volume expansion was followed by a drop of DVpeakao (from 16.04 +/- 1.99 to 2.97 +/- 1.65 %, p < 0.001) and DVTIao (from 20.43 +/- 5.13 to 3.43 +/- 1.68 %, p < 0.001) and CI increase (from 2.14 +/- 0.47 to 3.29 +/- 0.57 l/min/m2, p < 0.001). This increase strongly correlated with the value of DVpeakao (r = 0.782, p = 0.008) and DVTIao (r = 0.770, p = 0.009) before volume expansion. Conversely, there was no change of measured parameters in group B. Threshold values of 14% for DVaopeak and 17% for DVTIao were identified to predict fluid responsiveness (increase of CI > 15%) with a sensitivity of 89% and specificity of 100%. CONCLUSIONS: DVpeakao and DVTIao reflect preload-dependent changes of CI in healthy spontaneously breathing volunteers and predict fluid responsiveness.

Neuraxial anesthesia is less harmful to the endothelial glycocalyx during elective joint surgery compared to general anesthesia.

BACKGROUND: Damage of the endothelial glycocalyx (EG) has been described during surgery, but the effect of different anesthesia techniques remains unknown. Perfused boundary region (PBR) evaluated by side-stream dark field (SDF) imaging of the sublingual microcirculation enables in vivo EG assessment. PBR values are inversely related to the EG thickness. OBJECTIVE: The aim of the observational study was to evaluate the changes of PBR in patients undergoing elective joint surgery under general (GA) vs. neuraxial anesthesia (NA). Our hypothesis was that PBR will be lower in patients in NA. METHODS: Sixty consecutive patients (ASA 1-3) undergoing elective total knee or hip replacement under GA or NA were included in this prospective observational cohort study. PBR in the sublingual microcirculation was recorded in each patient using SDF at two time points - before surgery and 2 hours after surgery. RESULTS: Before surgery, there was no significant difference in baseline PBR between groups (NA: 1.95 µm (±0.24); GA: 2.02 µm (±0.26); p = 0.098). Postoperatively (2 hours after surgery) PBR was significantly increased in both groups with respect to baseline values (NA: 2.09 µm (±0.19), GA: 2.20 µm (±0.25); p < 0.001). In the GA group, postoperative PBR values were significantly higher than in the NA group (p = 0.006). CONCLUSION: Joint surgery led to significant increases of PBR. Patients in the GA group had significantly higher PBR values 2 hours after surgery compared to NA group. This might implicate that NA is associated with less EG damage then GA in elective hip/knee surgery.

Effect of short-term administration of lipid emulsion on endothelial glycocalyx integrity in ICU patients - A microvascular and biochemical pilot study.

BACKGROUND: Endothelial glycocalyx (EG) is a carbohydrate-rich vascular lining of the apical surface of endothelial cells. It has been proved to have an essential role in vascular homeostasis. Lipid emulsions as part of parenteral nutrition (PN) are widely used in patients in the setting of critical care and perioperative medicine. Due to their structure, lipids may potentially interact with EG. The aim of the study was to evaluate the effect of lipid emulsion on EG. OBJECTIVE: To assess the influence of lipid emulsion on EG integrity in ICU patients using a videomicroscopic and biochemical methods. METHODS: Patients in surgical ICU after major abdominal surgery or cardio surgery and in general ICU were assessed for eligibility for this pilot observational study in University Hospital. The study was performed during the first day of adding lipids as a part of their PN. The patients were given the SMOFlipid 20% for 6 hours in prescribed dose of approx. 1 g/kg of body weight. EG integrity was measured indirectly by automated sublingual videomicroscopy calculating a parameter PBR which describes the amount of lateral deviation of red blood cells from the central column and by levels of syndecan-1 and syndecan-4 in plasma as EG degradational products. Measurements were performed before lipid administration (T0) and 30 minutes after (T6) the infusion of lipid emulsion was completed. The statistical analysis was performed at the level of significance p < 0.05, data are expressed as mean ± standard deviation (SD) and for PBR as median and interquartile range (IQR). RESULTS: Fifteen patients were studied, from them 9 included in final analysis. PBR (expressed in µm) increased after the lipid infusion with no statistical significance (T0 = 2.10; 1.97-2.33 vs. 2.28; 2.11-2.45, p = 0.13). At T6 both syndecans showed statistically significant decrease in their particular levels. Syndecan-1 at T0 = 2580±1013 ng/l, resp. at T6 = 2365±1077 ng/l, p = 0.02; syndecan-4 at T0 = 134±29 ng/l, resp. at T6 = 123±43 ng/l, p = 0.04. CONCLUSION: In our study, we showed that six hours long SMOFlipid 20% infusion had no detrimental effect on the EG integrity as assessed by PBR value and by syndecan-1 and syndecan-4 plasmatic levels. Observed decrease of syndecans shortly after lipid infusion allows us to hypothesize even possibly protecting effect of lipids on EG.