Pharmacokinetic and Pharmacodynamic Analyses To Determine the Optimal Fixed Dosing Regimen of Iclaprim for Treatment of Patients with Serious Infections Caused by Gram-Positive Pathogens.

Iclaprim is a bacterial dihydrofolate reductase inhibitor that is currently being evaluated in two phase 3 trials for the treatment of patients with acute bacterial skin and skin structure infections (ABSSSI). Prior animal infection model studies suggest that the pharmacokinetic/pharmacodynamic (PK/PD) drivers for efficacy are area under the concentration-time curve from 0 to 24 h at steady state (AUC0-24ss), AUC/MIC, and time above the MIC during the dosing interval (T > MIC), while QTc prolongation was associated with the maximal concentration at steady state (Cmaxss) in a thorough QTc phase 1 study. Using PK data collected from 470 patients from the previously conducted phase 3 complicated skin and skin structure infection (cSSSI) trials, population PK modeling and Monte Carlo simulation (MCS) were used to identify a fixed iclaprim dosage regimen for the ongoing phase 3 ABSSSI studies that maximizes AUC0-24ss, AUC/MIC, and T > MIC while minimizing the probability of a Cmaxss of ≥800 ng/ml relative to the values for the previously employed cSSSI regimen of 0.8 mg/kg of body weight infused intravenously over 0.5 h every 12 h. The MCS analyses indicated that administration of 80 mg as a 2-h infusion every 12 h provides 28%, 28%, and 32% increases in AUC0-24ss, AUC/MIC, and T > MIC, respectively, compared to values for the 0.8-mg/kg cSSSI regimen, while decreasing the probability of a Cmaxss of ≥800 ng/ml, by 9%. Based on PK/PD analyses, 80 mg iclaprim administered over 2 h every 12 h was selected as the dosing scheme for subsequent phase 3 clinical trials.

Time of Day When Type 1 Diabetes Patients With Eating Disorder Symptoms Most Commonly Restrict Insulin.

OBJECTIVE: Restricting insulin to lose weight is a significant problem in the clinical management of type 1 diabetes (T1D). Little is known about this behavior or how to effectively intervene. Identifying when insulin restriction occurs could allow clinicians to target typical high-risk times or formulate hypotheses regarding factors that influence this behavior. The current study investigated the frequency of insulin restriction by time of day. METHODS: Fifty-nine adults with T1D and eating disorder symptoms completed 72 hours of real-time reporting of eating and insulin dosing with continuous glucose monitoring. We used a generalized estimating equation model to test the global hypothesis that frequency of insulin restriction (defined as not taking enough insulin to cover food consumed) varied by time of day, and examined frequency of insulin restriction by hour. We also examined whether patterns of insulin restriction for 72 hours corresponded with patients' interview reports of insulin restriction for the past 28 days. RESULTS: Frequency of insulin restriction varied as a function of time (p = .016). Insulin restriction was the least likely in the morning hours (6:00-8:59 AM), averaging 6% of the meals/snacks consumed. Insulin restriction was more common in the late afternoon (3:00-5:59 PM), peaking at 29%. Insulin was restricted for 32% of the meals/snacks eaten overnight (excluding for hypoglycemia); however, overnight eating was rare. Insulin restriction was associated with higher 120-minute postprandial blood glucose (difference = 44.4 mg/dL, 95% confidence interval = 22.7-68.5, p < .001) and overall poorer metabolic control (r = 0.43-0.62, p's < .01). Patients reported restricting insulin for a greater percentage of meals and snacks for the past 28 days than during the 72 hour real-time assessment; however, the reports were correlated (Spearman's ρ = 0.46, p < .001) and accounted for similar variance in HbA1c (34% versus 35%, respectively). CONCLUSIONS: Findings suggest that insulin restriction may be less likely in the morning, and that late afternoon is a potentially important time for additional therapeutic support. Results also suggest that systematic clinical assessment and treatment of overnight eating might improve T1D management.

Impacts of Industrial Wind Turbine Noise on Sleep Quality: Results From a Field Study of Rural Residents in Ontario, Canada.

The objectives of this study were to determine whether grid-connected industrial wind turbines (IWTs) are a risk factor for poor sleep quality, and if IWT noise is associated with sleep parameters in rural Ontarians. A daily sleep diary and actigraphy-derived measures of sleep were obtained from 12 participants from an IWT community and 10 participants from a comparison community with no wind power installations. The equivalent and maximum sound pressure levels within the bedroom were also assessed. No statistically significant differences were observed between IWT residents and non-IWT residents for any of the parameters measured in this study. Actigraphy and sleep diaries are feasible tools to understand the impact of IWTs on the quality of sleep for nearby residents. Further studies with larger sample sizes should be conducted to determine whether the lack of statistical significance observed here is a result of sample size, or reflects a true lack of association.

Impact of single immunosuppressive drug withdrawal on lymphocyte immunoreactivity.

BACKGROUND: Chronic rejection is a major cause of graft loss in kidney transplant recipients. Nonadherence to drug therapy is a well-recognized cause of chronic rejection leading to long-term graft dysfunction and failure for transplant recipients. Immunosuppressive medications with short half-lives that require frequent dosing, such as tacrolimus, complicate transplant regimens and may increase noncompliance. Regimens could be simplified using drugs with long half-lives requiring once-daily administration, such as sirolimus. The impact of missing doses of single agents has not been studied extensively. Erratic compliance or temporary discontinuation of immunosuppressive drugs may have significant implications for chronic rejection. METHODS: Our study evaluated the impact of single drug withdrawal of commonly used immunosuppressive agents (sirolimus and tacrolimus) on lymphocyte responses. We analyzed lymphocyte proliferation, cytokine secretion, and adenosine triphosphate generation using a crossover study design with normal healthy patients. Lymphocyte proliferation was assessed using 5-bromo-2-deoxyuridine incorporation, and T cell function was analyzed by examining adenosine triphosphate generation. RESULTS: Our results indicate that sirolimus exerts prolonged suppression of lymphocyte proliferation and decreased interleukin 17A that lasts up to 48 h after drug withdrawal. In comparison, tacrolimus did not have a similar effect on lymphocyte proliferation or interleukin 17A secretion. CONCLUSION: Future analysis of sirolimus in diverse transplantation populations merits investigation.

Impact of body position on hemodynamic measurements during exercise: A tale of two bikes.

The addition of exercise testing during right heart catheterization (RHC) is often required to accurately diagnose causes of exercise intolerance like early pulmonary vascular disease, occult left heart disease, and preload insufficiency. We tested the influence of body position (supine vs. seated) on hemodynamic classification both at rest and during exercise. We enrolled patients with exercise intolerance due to dyspnea who were referred for exercise RHC at the Cleveland Clinic. Patients were randomized (1:1) to exercise in seated or supine position to a goal of 60 W followed by maximal exercise in the alternate position. We analyzed 17 patients aged 60.3 ± 10.9 years, including 13 females. At rest in the sitting position, patients had significantly lower right atrial pressure (RAP), mean pulmonary artery pressure (mPAP), pulmonary artery wedge pressure (PAWP) and cardiac index (CI). In every stage of exercise (20, 40, and 60 W), the RAP, mPAP, and PAWP were lower in the sitting position. Exercise in the sitting position allowed the identification of preload insufficiency in nine patients. Exercise in either position increased the identification of postcapillary pulmonary hypertension (PH). Body position significantly influences hemodynamics at rest and with exercise; however, mPAP/CO and PAWP/CO were not positionally affected. Hemodynamic measurements in the seated position allowed the detection of preload insufficiency, a condition that was predominantly identified as no PH during supine exercise.

Validating the anatomical landmark technique for bedside tunneled central venous catheter placement in the medical intensive care unit.

BACKGROUND: A non-tunneled dialysis catheter (nTDC) is often the vascular access of choice to initiate dialysis in an intensive care unit (ICU). In the absence of contraindications, if a patient remains dialysis dependent beyond 2-weeks, the options are either to replace the nTDC with another nTDC or convert to a tunneled dialysis catheter (TDC). As a standard of care, TDCs are placed under fluoroscopic guidance. OBJECTIVES: To determine if TDCs and other tunneled central venous catheters (tCVC) can be placed safely using anatomical landmark techniques without the use of fluoroscopy. RESEARCH DESIGN: Subjects that met a predetermined selection criteria underwent placement of tunneled catheters with the use of the anatomical landmark technique. We looked at various outcomes to determine the safety and effectiveness of this technique. SUBJECTS: One hundred eleven TDCs and other tCVCs were placed using the anatomical landmark technique in the intensive care unit. RESULTS: All but one (110/111) of the catheters placed had recommended tip placement confirmed by at least one blinded physician. Major complications encountered were bleeding (two cases), pneumothorax (one case), and line associated blood stream infection (one case). We did find a higher-than-expected rate of "unnecessary procedures" with 18/111 lines placed in patients who did not survive beyond 7 days after placement of the catheter. CONCLUSIONS: Using the anatomical landmark technique for bedside tunneled catheter placement can be an effective approach in the right population.

Concomitant percutaneous coronary intervention and transcatheter aortic valve replacement: safe and feasible replacement alternative approaches in high-risk patients with severe aortic stenosis and coronary artery disease.

OBJECTIVE: Transcatheter aortic valve replacement (TAVR) is performed as a stand-alone procedure in patients that are not suitable for surgical aortic valve replacement. However, a significant proportion of patients with severe aortic stenosis have coexisting coronary artery disease (CAD). We report concomitant TAVR and percutaneous coronary intervention (PCI) as a single procedure in such patients. METHODS: Three patients with severe aortic stenosis and CAD that were high risk for conventional surgery had concomitant alternative approach TAVR and PCI performed. Two patients had PCI and stent placement immediately after the deployment of the transapical transcatheter aortic valve, and one patient had a coronary artery stent placed just prior to the deployment of the transaortic transcatheter aortic valve. RESULTS: Two male patients and one female (age range 68-91 years) had 100% procedural success with resolution of symptoms and zero residual stenosis. There were no complications related to neurologic events, worsening renal function, or myocardial infarction. In-hospital and 30-day mortality was zero. All three patients were discharged home with a median hospital stay of eight days. CONCLUSIONS: In our small series of patients presented we demonstrate that PCI and TAVR performed concurrently in the hybrid operating room is a feasible option in patients undergoing TAVR with coexisting CAD. Furthermore, we propose this single-stage approach in such high-risk patients as it decreases the number of procedures performed and may theoretically lower cost and hospital stay.

Challenges with tunneled dialysis catheter placement with subcutaneous emphysema.

Central vein catheter is a convenient and preferred vascular access for blood purification therapy in intensive care unit. Utilizing ultrasound to access the central vein is considered standard of care. However, critically ill patients can pose challenges while acquiring an optimal ultrasound image. The presence of subcutaneous air pockets, concerns for air embolism, and excessive bleeding from the exit site is one such clinical situation. We describe our experience with a unique situation while placing a tunneled dialysis catheter in a COVID-19 patient with acute respiratory failure and subcutaneous emphysema.

Fluid loading during the hemodynamic evaluation of pulmonary hypertension: a cross-sectional study.

Background: Compensated pulmonary hypertension due to left heart disease (PH-LHD) may be difficult to identify based on resting hemodynamics. Fluid challenge is commonly used to unmask occult PH-LHD. We sought to determine the hemodynamic effect of fluid loading and its association with the clinical pretest probability of PH-LHD. Methods: We included consecutive patients evaluated for PH who underwent right heart catheterization (RHC) with fluid challenge at Cleveland Clinic between April 2013 and January 2019. We obtained hemodynamic measurements at rest and after intravenous rapid fluid challenge (500 mL of normal saline). We calculated the pretest probability of PH-LHD based on the 6th World Symposium on PH proceedings. For statistical analyses we used t-test, analysis of variance (ANOVA), Chi-square, paired t-test, Wilcoxon signed-rank test and linear regression as indicated. Results: We included 174 patients with mean ± standard deviation (SD) age of 63.7±13.0 years and 123 (71%) of female sex. Baseline pulmonary artery wedge pressure (PAWP) was 11±5 mmHg, with a PAWP/cardiac output (CO) ratio of 2.1±1.1 Wood units (WU). The absolute increase in PAWP and PAWP/CO was 6.9±3.6 mmHg and 1.06±0.91 WU, respectively. The change in PAWP was inversely associated with baseline PAWP (P<0.001). The PAWP with fluids was >18 mmHg in 81% of the patients with baseline PAWP 13-15 mmHg. We found no strong associations between the change in PAWP, PAWP/CO or right atrial pressure to pulmonary arterial wedge pressure ratio (RAP/PAWP) and the pretest probability of PH-LHD. Conclusions: The absolute change in PAWP, PAWP/CO, or achieving a PAWP >18 mmHg with rapid fluid loading was not robustly associated with the pretest probability of PH-LHD. Patients with PAWP between 13-15 mmHg commonly had a positive fluid challenge, questioning the utility of this intervention in these patients.

Impact on Pulmonary Hypertension Hemodynamic Classification Based on the Methodology Used to Measure Pulmonary Artery Wedge Pressure and Cardiac Output.

Rationale: Guidelines recommend using end-expiration pulmonary pressure measurements to determine the hemodynamic subgroups in pulmonary hypertension. Pulmonary artery wedge pressure (PAWP) determinations averaged across the respiratory cycle (PAWPav) instead of PAWP at end-expiration (PAWPee) and cardiac output (CO) measured by Fick (COFick) instead of thermodilution (COTD) may affect the hemodynamic classification of pulmonary hypertension. Objectives: To assess the impact on the pulmonary hypertension hemodynamic classification of the use of PAWPee versus PAWPav as well as COFick versus COTD. Methods: This was a single-center retrospective study of consecutive patients (n = 151) who underwent right heart catheterization with COTD, COFick, PAWPee, and PAWPav. A secondary cohort consisted of consecutive patients (n = 71) who had mean pulmonary artery pressure at end-expiration (mPAPee) and mPAP averaged across the respiratory cycle (mPAPav) measured, as well as PAWPee and PAWPav. Results: The PAWPee and PAWPav were 16.8 ± 6.4 and 15.1 ± 6.8 mm Hg, respectively, with a mean difference of 1.7 ± 2.1 mm Hg. The COTD and COFick determinations were 5.0 ± 2.4 and 5.3 ± 2.5 L/min, respectively, with a mean difference of -0.4 ± 1.3 L/min. The hemodynamic group distribution was significantly different when using PAWPee versus PAWPav, when using either COTD or COFick (P < 0.001 for both comparisons), and these results were consistent in our secondary cohort. The pulmonary hypertension hemodynamic group distribution was not significantly different between COTD and COFick when using either PAWPee or PAWPav. Conclusions: The methodology used to measure PAWP, either at end-expiration or averaged across the respiratory cycle, significantly impacts the hemodynamic classification of pulmonary hypertension.

Does veno-arterial carbon dioxide gradient provide an adequate estimation of cardiac index in pulmonary hypertension?

AIMS: Pulmonary hypertension (PH) management is dependent on cardiac output (CO) assessment. The gold standard Fick method for CO and cardiac index (CI) measurement is not widely available. An accessible and reliable method for CO/CI estimation is needed not only in catheterization labs but also in other environments such as the intensive care unit, where pulmonary artery catheters are less likely to be used. We hypothesized that veno-arterial carbon dioxide gradient (PvaCO2) is a reliable surrogate for Fick CI in patients with PH. METHODS AND RESULTS: A single-centre retrospective analysis of patients with PH who underwent direct Fick CI (DFCI) measurement during right heart catheterization. The primary outcome was correlation between PvaCO2 and DFCI. To assess the agreement between central and mixed venous CO2 values, a separate prospective cohort of patients was analysed. Data from 186 patients with all haemodynamic types of PH were analysed. PvaCO2 moderately correlated with Fick CI, R = -0.51 [95% confidence interval (CI): -0.61, -0.39]. A higher PvaCO2 was associated with an increased risk of CI < 2.5 L/min/m2 (odds ratio: 1.88, 95% CI: 1.55, 2.35). Low thermodilution CI with normal veno-arterial carbon dioxide gradient values was associated with a thermodilution underestimation of Fick CI. In the prospective analysis of 32 patients, central venous CO2 overestimated mixed venous values (mean difference 3.3, 95% CI: 2.5, 4.0) and there was poor agreement overall (limits of agreement -1.10, 7.59). CONCLUSION: Veno-arterial carbon dioxide gradient moderately correlates with Fick CI and may be useful to identify patients with low CI. Central and mixed venous CO2 values should not be used interchangeably in PH.

Can Inhaled Nitric Oxide Response Predict Tolerance to Therapies and Survival in Patients With Combined Precapillary and Postcapillary Pulmonary Hypertension?

Inhaled nitric oxide (iNO) relaxes the pulmonary circulation and variably increases the left ventricular preload and pulmonary artery wedge pressure (PAWP)-hemodynamic information that may help guide treatment decisions and assess prognosis in patients with combined precapillary and postcapillary pulmonary hypertension (PH). We included consecutive patients with combined precapillary and postcapillary PH (mean pulmonary artery pressure >20 mm Hg, PAWP >15 mm Hg, and pulmonary vascular resistance [PVR] >2 Woods unit [WU]) who underwent right-sided cardiac catheterization with iNO at the Cleveland Clinic Pulmonary Vascular Disease program between 2017 and 2022. We included 104 patients with baseline PAWP and PVR of 22.2 ± 4.2 mm Hg and 6.1 ± 3.2 WU, respectively. Pulmonary arterial hypertension (PAH) with postcapillary component and PH left heart disease with precapillary component were identified in 27 (26%) and 77 patients (74%), respectively. No side effects were noted during the administration of iNO. During iNO, the PVR decreased 1.1 ± 1.4 WU and the PAWP increased 1.3 ± 3.7 mm Hg. A more pronounced increase in PAWP with iNO was associated with a decrease in PVR (R -0.35, p <0.001) and increase in stroke volume (R 0.20, p = 0.046). Tolerance to PAH-specific medications, overall survival, and heart failure hospitalizations were not significantly associated with the change in PAWP or PVR with iNO. In conclusion, in patients with combined precapillary and postcapillary PH, iNO challenge is safe and caused a significant decrease in PVR, with an increase in PAWP. The changes in PAWP and PVR during iNO administration were not associated with tolerance to PAH-specific medications, heart failure-related hospitalization, or survival.

Thromboelastography-Guided Correction of Coagulopathy Before Tunneled Central Venous Access in Critically Ill Patients With Liver Disease: A Propensity Score-Matched Study.

Importance: Optimal blood product transfusion strategies before tunneled central venous catheter (CVC) placement are required in critically ill coagulopathic patients with liver disease to reduce exposure to allogeneic blood products and mitigate bleeding and thrombotic complications. Objectives: This study evaluated the safety and efficacy of a thromboelastography-guided transfusion strategy for the correction of coagulopathy in patients with liver disease compared with a conventional transfusion strategy (using international normalized ratio, platelet count, and fibrinogen) before tunneled CVC insertion. Design Setting and Participants: A retrospective propensity score-matched single-center cohort study was conducted at a quaternary care academic medical center involving 364 patients with liver disease (cirrhosis and acute liver failure) who underwent tunneled CVC insertion in the ICU. Patients were stratified into two groups based on whether they received blood product transfusions based on a thromboelastography-guided or conventional transfusion strategy. Main Outcomes and Measures: Primary outcomes that were evaluated included the volume, units and cost of blood products (fresh frozen plasma, cryoprecipitate, and platelets) when using a thromboelastography-guided or conventional approach to blood transfusions. Secondary outcomes included the frequency of procedure-related bleeding and thrombotic complications. Results: The total number of units/volume/cost of fresh frozen plasma (12 U/3,000 mL/$684 vs. 32 U/7,500 mL/$1,824 [p = 0.019]), cryoprecipitate (60 U/1,500 mL/$3,240 vs. 250 U/6,250 mL/$13,500 [p < 0.001]), and platelets (5 U/1,500 mL/$2,610 vs. 13 units/3,900 mL/$6,786 [p = 0.046]) transfused were significantly lower in the thromboelastography-guided transfusion group than in the conventional transfusion group. No differences in the frequency of bleeding/thrombotic events were observed between the two groups. Conclusions and Relevance: A thromboelastography-guided transfusion strategy for correction of coagulopathy in critically ill patients with liver disease before tunneled CVC insertion, compared with a conventional transfusion strategy, reduces unnecessary exposure to allogeneic blood products and associated costs without increasing the risk for peri-procedural bleeding and thrombotic complications.

Single-dose rATG induction at renal transplantation: superior renal function and glucoregulation with less hypomagnesemia.

BACKGROUND: Rabbit anti-thymocyte globulin (rATG) induction reduces reperfusion injury and improves renal function in kidney recipients by means of properties unrelated to T-cell lysis. Here, we analyze intensive rATG induction (single dose, rATG(S) , vs. divided dose, rATG(D) ) for improved renal function and protection against hyperglycemia. METHODS: Patients without diabetes (n = 98 of 180) in a prospective randomized trial of intensive rATG induction were followed for six months for the major secondary composite end point of impaired glucose regulation (hyperglycemia and new-onset diabetes after transplantation, NODAT). Prospectively collected data included fasting blood glucose and HbA(1c). Serum Mg(++) was routinely collected and retrospectively analyzed. RESULTS: Induction with rATG(S) produced less impaired glucose regulation (p = 0.05), delayed NODAT development (p = 0.02), less hyperglycemia (p = 0.02), better renal function (p = 0.04), and less hypomagnesemia (p = 0.02), a factor associated with a lower incidence of NODAT. Generalized linear modeling confirmed that rATG(S) protects against a synergistic interaction between tacrolimus and sirolimus that otherwise increased hypomagnesemia (p = 0.008) and hyperglycemia (p = 0.03). CONCLUSIONS: rATG(S) initiated before renal reperfusion improved early renal function and reduced impaired glucose regulation, an injury by diabetogenic maintenance agents (tacrolimus and sirolimus).

Effect of pulmonary artery catheter balloon inflation on pulmonary hemodynamics.

Background: Right heart catheterization (RHC), including a pulmonary artery wedge pressure (PAWP) determination, is necessary to categorize the hemodynamic type of pulmonary hypertension (PH). The potential hemodynamic implications of a pulmonary artery catheter (PAC) balloon inflation in PH have not been formally tested. Methods: We assessed the hemodynamic impact of the PAC balloon inflation during RHC by measuring systolic, diastolic, and mean pulmonary artery pressure (mPAP) in all patients, and cardiac output (CO) by thermodilution in a subgroup of patients. Hemodynamic measurements were obtained both with PAC balloon deflated and fully inflated (1.5 mL of air), while the PAC was free floating in the pulmonary artery before wedging. We calculated total pulmonary resistance (TPR). Results: We included 210 patients, age 58±14 years, 134 (64%) women. Patients had no PH (n: 12, 6%), PH group 1 (n: 68, 33%), 2 (n: 86, 41%), 3 (n: 11, 5%), 4 (n: 29, 14%), and 5 (n: 3, 1%). The mean ± standard deviation (SD) at end-expiration mPAP (balloon-up minus down) (n: 209) was -0.02±1.59 mmHg (range, -5.0 to 4.0 mmHg; P=0.84), while the TPR (n: 62) was -0.27±1.2 Wood units (WU) (range, -4.8 to 2.2 WU; P=0.08); without significant variation based on the type of PH group or degree of pulmonary vascular resistance (PVR). Interestingly, the change in mPAP at end-expiration with PAC balloon inflation was higher in women (mean ± SD: 0.31±1.43 mmHg) than men (mean ± SD: -0.61±1.70 mmHg) (P<0.001). Conclusions: Balloon inflation of the PAC in the main pulmonary artery had no significant impact on the mPAP or TPR, even when only including patients with group 1 PH or selecting a subgroup with a higher PVR.

Simultaneous Measurement of Endothelial Cell Proliferation and Cell Cycle Stage Using Flow Cytometry.

Endothelial cell proliferation rate is an important indicator of vascular health. Being able to detect the rate of endothelial cell proliferation, or cell cycle disturbances after intervention is a valuable tool for analysing any beneficial or detrimental effects of treatments in vitro. Here, we describe a straightforward flow cytometric-based method of proliferation and cell cycle tracking that can be performed on human endothelial cells in culture over several days.

Safety of bedside placement of tunneled dialysis catheter in COVID-19 patients.

COVID-19 patients admitted to the ICU have high incidence of AKI requiring prolonged renal replacement therapy and often necessitate the placement of a tunneled dialysis catheter (TDC). We describe our experience with two cases of COVID-19 patients who underwent successful bedside placement of TDC under ultrasound guidance using anatomical landmarks without fluoroscopy guidance. Tunneled dialysis catheter placement under direct fluoroscopy remains the standard of care; but in well selected patients, placement of tunneled dialysis catheter at the bedside using anatomic landmarks without fluoroscopy can be safely and successfully performed without compromising the quality of care and avoid transfer of COVID-19 infected patients outside the ICU.

Use of a Thin Layer Assay for Assessing the Angiogenic Potential of Endothelial Cells In Vitro.

Angiogenesis is essential for wound healing and regeneration and plays a significant role in several pathologies including cancer and atherosclerosis. In vitro assays offer simple and powerful tools for investigating the regulation of the angiogenic functions of primary endothelial cells (ECs) before moving to in vivo studies. The classic in vitro two-dimensional angiogenesis assay utilizes Basement Membrane Extract (BME) to study the differentiation and sprouting of ECs over a 24-h period. The protocol described here details a thin layer BME adaptation of the angiogenesis assay requiring significantly less BME and carried out in 96-well plates, allowing for a larger data yield at a greatly reduced cost, while maintaining the robustness of an assay used extensively over the past three decades.

Impact of Esophageal Pressure Measurement on Pulmonary Hypertension Diagnosis in Patients With Obesity.

BACKGROUND: Elevated intrathoracic pressure could affect pulmonary vascular pressure measurements and influence pulmonary hypertension (PH) diagnosis and classification. Esophageal pressure (Pes) measurement adjusts for the increase in intrathoracic pressure, better reflecting the pulmonary hemodynamics in patients with obesity. RESEARCH QUESTION: In individuals with obesity, what is the impact of adjusting pulmonary hemodynamic determinations for Pes on PH diagnosis and classification? Can Pes be estimated by positional or respiratory hemodynamic changes? STUDY DESIGN AND METHODS: In this prospective cohort study, we included patients with obesity who underwent right heart catheterization and demonstrated elevated pulmonary artery wedge pressure (PAWP; ≥ 12 mm Hg). After placement of an esophageal balloon, we performed pressure determination using an air-filled transducer connected to a regular hemodynamic monitor. We measured pulmonary pressures changes when sitting and the variations during the respiratory cycle. RESULTS: We included 53 patients (mean ± SD age, 59 ± 12 years; mean ± SD BMI, 44.4 ± 10.2 kg/m2). Supine end-expiratory pressures revealed a mean pulmonary artery pressure of > 20 mm Hg in all patients and a PAWP of >15 mm Hg in most patients (n = 50). The Pes adjustment led to a significant decrease in percentage of patients with postcapillary PH (from 60% to 8%) and combined precapillary and postcapillary PH (from 34% to 11%), at the expense of an increase in percentage of patients with no PH (0% to 23%), isolated precapillary PH (2% to 25%), and undifferentiated PH (4% to 34%). INTERPRETATION: Adjusting pulmonary hemodynamics for Pes in patients with obesity leads to a pronounced reduction in the number of patients who receive a diagnosis of postcapillary PH. Measuring Pes should be considered in patients with obesity, particularly those with elevated PAWP.

Safety of Bedside Placement of Tunneled Hemodialysis Catheters in the Intensive Care Unit: Translating from the COVID-19 Experience.

BACKGROUND: Critically ill patients with coronavirus disease 2019 (COVID-19) and kidney dysfunction often require tunneled hemodialysis catheter (TDC) placement for kidney replacement therapy, typically under fluoroscopic guidance to minimize catheter-related complications. This entails transportation of patients outside the intensive care unit to a fluoroscopy suite, which may potentially expose many healthcare providers to COVID-19. One potential strategy to mitigate the risk of viral transmission is to insert TDCs at the bedside, using ultrasound and anatomic landmarks only, without fluoroscopic guidance. METHODS: We reviewed all COVID-19 patients in the intensive care unit who underwent right internal jugular TDC insertion at the bedside between April and December 2020. Outcomes included catheter placement-related complications such as post-procedural bleeding, air embolism, dysrhythmias, pneumothorax/hemothorax, and catheter tip malposition. TDC insertion was considered successful if the catheter was able to achieve blood flow sufficient to perform either a single intermittent or 24 h of continuous hemodialysis treatment. RESULTS: We report a retrospective, single-center case series of 25 patients with COVID-19 who had right internal jugular TDCs placed at the bedside, 10 of whom underwent simultaneous insertion of small-bore right internal jugular tunneled central venous catheters for infusion. Continuous veno-venous hemodialysis was utilized for kidney replacement therapy in all patients, and a median catheter blood flow rate of 200 mL/min (IQR: 200-200) was achieved without any deviation from the dialysis prescription. No catheter insertion-related complications were observed, and none of the catheter tips were malpositioned. CONCLUSIONS: Bedside right internal jugular TDC placement in COVID-19 patients, using ultrasound and anatomic landmarks without fluoroscopic guidance, may potentially reduce the risk of COVID-19 transmission among healthcare workers without compromising patient safety or catheter function. Concomitant insertion of tunneled central venous catheters in the right internal jugular vein for infusion may also be safely accomplished and further help limit personnel exposure to COVID-19.