ABSTRACT
Background: Septic shock, defined as organ dysfunction caused by a dysregulated host response to infection, is a condition associated with high morbidity and mortality. One of the hallmarks of sepsis is the excessive release of cytokines and other inflammatory mediators that cause septic shock and multi-organ failure (MOF). New adsorbents are now available as adjuvant therapy aimed at modulating the cytokine "storm" in sepsis. They are thought to be useful if adopted early (within 8-24 hours of the diagnosis of septic shock) in patients who are unresponsive to standard therapy. Here we report our experience with CytoSorb. Method(s): From January 2021 to May 2022, 46 patients with septic shock were treated with continuous renal replacement therapy (CRRT) associated with hemoadsorption with CytoSorb. All cases presented organ failure including AKI. Surgical patients (n = 13) were treated with surgery, COVID patients (n = 15) and medical patients (n = 16) with medical therapy;all surgery cases were operated on before starting the haemadsorption and in some cases reoperation with the need to suspend the adsorption. The mean age was 69 +/- 17 years (SD). On admission the mean SAPSII score was 50 +/- 11 (SD). CRRT as hemodiafiltration (CVVHDF) was performed. All patients received at least one CytoSorb treatment and additional treatments (up to 21 filters in a Covid patient) according to our indication. The CytoSorb cartridge was installed in series to the high cut-off filter;blood flow rates were maintained between 120 and 150 mL/min while dialysis doses from 18 to 45 mL/kg/hour. CytoSorb was renewed every 24 hours. We evaluated the impact of CytoSorb on 30-day survival, haemodynamics and relevant outcomes. Result(s): The 30-day survival was 30%. During treatment with CytoSorb, patients had a hemodynamic stabilization with a significant improvement in MAP, a reduction in amines and a decrease in PCR and PCT (Figure 1). Mortality at 30 days among medical patients was almost comparable to that of COVID patients and higher than that of surgical patients (70%, 69% and 61%, respectively). It should be noted that almost half of the deceased patients arrived late in the hospital, thus leading to a late start of treatment. Conclusion(s): We confirm the efficacy and usefulness of the CytoSorb if adopted early in patients who do not respond to standard therapy. CytoSorb treatment was safe and well tolerated with no device-related adverse events during or after treatment sessions.
ABSTRACT
Dental implants are a standard of care in contemporary dental practice and are widely employed for the restoration of missing teeth. The long-term utility of an implant is largely dependent on the successful implant osseointegration and maintenance of the same over time. Bone metabolism and inflammatory mechanism are interrelated phenomena and are usually collectively termed osteoimmunology, which may affect the predictability and success of implant osseointegration. Many biochemical mediators of inflammation, especially Interleukin (IL)1, IL-6, and Tumour necrosis factor (TNF)alpha, have been documented to increase the activity of bone-resorbing cells through the Receptor Activator of Nuclear Factor Kappa-B (RANK) and Receptor Activator of Nuclear Factor Kappa-B Ligand (RANKL)systems. Some of the earlier studies with very limited data suggest that SARS-CoV2 infection may also directly affect bone resorption. Thus, it is imperative to understand the pathophysiology of osseointegration in COVID-19 patients, to enhance successful implant osseointegration and prevent peri-implant bone loss in these patients. Here, we present a summary of the connection between inflammatory pathways and bone metabolism on a molecular basis which may assume a significant bearing in situations of exaggerated host immune response as seen in COVID-19 infection.Copyright © 2022 Wolters Kluwer Medknow Publications. All rights reserved.
ABSTRACT
Background: The Covid-19 pandemic has introduced a number of challenges in managing populations with both acute kidney failure and those dependent on chronic dialysis. Due to a shortage of outpatient dialysis supplies, on February 14, 2022, the Dpt. of Veteran's Affairs issued a memorandum to dialysis units requiring a contingency standard of care. This required a universal reduction of dialysate flow rate to 500 cc/min. Prior to this change, the standard prescription at the Lexington, KY VA unit was 750 cc/min. We evaluated the effect of this change on the adequacy of our dialysis population. Method(s): Data was collected for sp Kt/V urea and urea reduction ratio for 17 chronic hemodialysis patients for the two months prior and three months following the reduction of dialysate flow rate to 500 cc/min from the previous standard of 750 cc/min. There was no change of blood flow rate or dialysis time during this 5 month period for all the patients included. Result(s): A trend towards lower clearance values as measured by single-pool Kt/V and urea reduction ratio was noted between January and April of 2022. Table 1 shows the average spKt/V and URR for each month. The majority of patients maintained adequate spKt/V of >1.2 and urea reduction ratio of >65%. However, 4 patients (23.5% of the population) failed to reach Kt/V and URR goal in April 2022. Conclusion(s): Though this represents only 17 patients from one dialysis unit, the data suggests a significant decline in adequacy due to this reduction in dialysis flow rate to 500 cc/min. Until the current dialysis supply shortage has been addressed, adaptive measures such as utilizing higher efficiency dialyzers or increasing blood flow rates may be necessary.
ABSTRACT
Aim of the study. To examine the effect of prone positioning on hemodynamics in patients with COVID-19. Materials and methods. The study enrolled 84 patients of both sexes with community-acquired multiseg-mental viral and bacterial pneumonia associated with COVID-19, who were divided into groups according to the type of respiratory support. The tests were performed using the integrated hardware and software system for noninvasive central hemodynamic assessment by volumetric compression oscillometry. Results. We found that the pulse blood pressure velocity decreased from 281 [242.0;314.0] to 252 [209;304] mm Hg/s in patients with severe COVID-19 on oxygen support (p=0.005);volume ejection rate decreased from 251 [200;294] to 226 [186;260] ml/s (P=0.03);actual/estimated normalized vascular resistance ratio dropped from 0.549 [0.400;0.700] to 0.450 [0.300;0.600] (P=0.002), while the arterial wall compliance increased from 1.37 [1.28;1.67] to 1.45[1.10;1.60] ml/mm Hg (P=0.009). Prone positioning of patients on noninvasive lung ventilation associated with a reduction of linear blood flow rate from 40.0 [34.0;42.0] to 42.5 [42.5;47.25] cm/s (P=0.04) and arterial wall compliance from 1.4 [1.24;1.50] to 1.32 [1.14;1.49] ml/mm Hg (P=0.03). Prone positioning of patients on invasive lung ventilation did not result in significant hemodynamic changes. Conclusion. The greatest hemodynamic changes during prone positioning were found in patients on oxygen respiratory support, whereas the least significant alterations were seen in patients on invasive ventilatory support. Copyright © 2021, V.A. Negovsky Research Institute of General Reanimatology. All rights reserved.
ABSTRACT
Introduction: Acute kidney injury in intensive care units (ICUs) is often treated with Continuous Renal Replacement Therapy (CRRT). Longer and uninterrupted CRRT sessions benefit patients, providers, and institutions. The impact of acute dialysis catheters on CRRT efficiency has only been evaluated in limited, single-centered Australian studies. This multicenter retrospective analysis examines associations between catheter type and multiple CRRT efficiency-related outcomes in a general ICU population. Method(s): CRRT session data from April 2018-July 2020 in two US ICUs were analyzed. Both units replaced three different acute dialysis catheters with a single new catheter in May 2019. Study intervals were divided into pre-/postchange periods, excluding a transition period (April-June 2019). To evaluate the pandemic's effects, the post-change period was further divided into pre-COVID/COVID periods. Outcome measures included treatment stoppage type (elective/non-elective), circuit life, blood flow rate, and frequency of all/vascular access (VA)-related alarm interruptions. Result(s): In total, 1,1037 CRRT sessions were analyzed. Compared to pre-change sessions (n=530), post-change period (n=507) had a reduced proportion of unintended stoppages (adjusted OR=0.42, 95% CI 0.28-0.62, p<0.001), longer circuit life (adjusted OR=1.31, 95% CI 1.14-1.49, p<0.001), increased blood flow rate (adjusted OR=1.03, 95% CI 1.01-1.05, p<0.01), and fewer VA-related interruptions (adjusted OR=0.80, 95% CI 0.66-0.96, p=0.014) and all interruptions (adjusted OR=0.95, 95% CI 0.87-1.05, p=0.31). Sessions during (n=340) and before (n=167) the pandemic were statistically similar except for a decreased proportion of unintended stoppages (adjusted OR=0.39, 95% CI 0.22-0.70, p<0.01). Discussion and conclusion: Adopting a different dialysis catheter was associated with longer CRRT sessions with fewer interruptions in the critically ill. Although the efficiency metrics were largely similar before and during the COVID19 pandemic, a notable increase in session volume was observed during the pandemic months. Future studies are warranted to evaluate the clinical impacts of CRRT efficiency and different catheter designs on patients and providers.
ABSTRACT
Background: The Extracorporeal Treatments in Poisoning (EXTRIP) workgroup provides a weak conditional recommendation in support of hemodialysis (HD) for select patients with severe phenytoin poisoning. Despite this recommendation, the HD clearance of phenytoin is poorly studied. We present a patient who developed phenytoin toxicity that was treated with hemodialysis and report on the efficacy of phenytoin removal during HD. Case report: An 87-year-old man with epilepsy who was maintained on a stable dose of 300mg phenytoin extended-release daily was admitted to the hospital for treatment of Coronavirus Disease 2019 and congestive heart failure. On hospital day 14, the patient had a gradual onset of depressed mental status with hypothermia (nadir 35 degrees Celsius). At this time, he had a rising total blood phenytoin concentration (peak 49.3 mcg/mL [therapeutic 10-20mcg/mL] with an albumin of 3.8 g/dL [normal 3.4-5.4 g/dL]). The patient's other medications included furosemide, aspirin, atorvastatin, digoxin, doxycycline, metoprolol tartrate, and warfarin;he was also receiving albumin and crystalloid for hypovolemia (albumin nadir on hospital day 14: 2.5 g/dL). Free phenytoin concentrations were not available. Alternate etiologies of hypothermia (endocrine, infectious) were excluded. The Poison Control Center was consulted and recommended HD because of the concern for prolonged coma, as per EXTRIP guidelines. The patient received three sessions of HD over a period of 6 days at 2.5-3 h per session using an F160 Optiflux membrane filter (Fresenius Medical Care, Waltham, MA, USA), with a blood flow rate of 350mL/min and a dialysate flow rate of 700mL/min. After the first session of HD (2.5 h) on hospital day 21, his hypothermia resolved and his phenytoin concentration fell from 39.2mcg/mL to 34.2 mcg/mL with only mild improvement in his mental status. After 6 days (hospital day 27), his phenytoin concentration decreased to 19.5 mcg/mL and his mental status normalized. Effluent from the first HD session had phenytoin concentrations below the limit of detection (0.50mcg/mL). Thus, no greater than 52mg of phenytoin was removed during a 2.5-h session of hemodialysis. Discussion(s): The reason for the sudden increase in blood phenytoin concentrations in this patient is unclear in the absence of drug-drug interactions or dosing changes to the phenytoin. Although uncommonly reported, patients with phenytoin toxicity can experience hypothermia. In this case, the patient's hypothermia resolved during HD, although it is unclear if this was related to changes in phenytoin concentration or (more likely) direct extracorporeal warming via the HD machine. If the patient's phenytoin clearance from the first session were extrapolated to subsequent sessions an estimated maximum of 166.4mg of phenytoin would be removed in 8 total hours of HD, which is far less than previously reported phenytoin clearances on the order of grams. This difference may be related to the use of high cutoff dialysis membranes in prior studies, which are not routinely used. Conclusion(s): Although HD rapidly resolved this patient's hypothermia, a minimal amount of phenytoin was recovered in the patient's dialysate. Prior studies suggesting consequential clearance and efficacy of phenytoin removal by extracorporeal treatment may not apply to routine HD methods. Further studies on the utility of extracorporeal treatment for phenytoin toxicity are needed.
ABSTRACT
The proceedings contain 226 papers. The topics discussed include: identification of biomarkers sensitive to pulsatile and continuous flow for identification of promising continuous flow VAD modulation protocols to mitigate non-surgical bleeding events;comprehensive machine learning analysis of pre-implantation risk factors for right heart failure after LVAD implantation;combining VA-ECMO And Impella (EC-Pella) before reperfusion mitigates left ventricular loading and injury due to VA-ECMO in acute myocardial infarction;platelet function at the intersection of the COVID-19 'cytokine storm' and mechanical circulatory support;a dialysate free portable artificial kidney device;durable right heart mechanical support system: a multi-day proof-of-concept study in pulmonary hypertension sheep;a dual-action nitric oxide-releasing slippery surface coating for extracorporeal organ support: first evaluation at clinically relevant blood flow rate for partial lung support;cannula add-on for pressure and flow measurement in VADs;and comparison of interlaboratory CFD simulations of the FDA benchmark blood pump model.
ABSTRACT
Background: Continuous Renal Replacement Therapy (CRRT) is commonly used in intensive care units (ICUs) to treat patients that develop acute kidney injury. Efficient CRRT can minimize differences between prescribed and delivered hemodialytic doses and reduce alarm fatigue. The role of acute dialysis catheters in CRRT efficiency has been assessed in single-center Australian studies focusing on circuit life. This multi-center retrospective analysis examines associations between catheter type and a comprehensive set of CRRT efficiency-related measures in the ICUs of two hospitals caring for patients with medical, surgical, and other critical illnesses. Methods: CRRT session data from two US ICUs between April 2018 and July 2020 were analyzed. Both units transitioned to a single new acute dialysis catheter from three different catheters in May 2019. The transition period (April 2019-June 2019) was excluded, and study intervals were divided into pre-and post-change periods. The post-change period was further divided into pre-COVID and COVID management periods to assess the pandemic's impacts. Outcome measures included frequency of alarm interruptions (all/vascular access [VA]-related alarms), circuit life, blood flow rate, and treatment stoppage type (elective/non-elective). Results: The final dataset included 1,1037 dialysis sessions. Relative to the pre-change period (n=530), post-change sessions (n=507) had fewer VA-related interruptions (adjusted OR=0.80, 95% CI 0.66-0.96, p=0.014), and all interruptions (adjusted OR=0.95, 95% CI 0.87-1.05, p=0.31), lower proportion of non-electively terminated sessions (adjusted OR=0.42, 95% CI 0.28-0.62, p<0.001), increased blood flow rate (adjusted OR=1.03, 95% CI 1.01-1.05, p<0.01), and longer circuit life (adjusted OR=1.31, 95% CI 1.14-1.49, p<0.001). Dialysis sessions before (n=167) and during COVID-19 (n=340) were comparable, excepting a lower proportion of unexpected stoppages (adjusted OR=0.39, 95% CI 0.22-0.70, p<0.01). Conclusion: Changing the acute dialysis catheter type was associated with longer CRRT sessions and fewer interruptions among a mixed population of critical patients in two US community hospitals. Pre-COVID CRRT sessions were similar in measures of efficiency to management during COVID-19;however, there was a striking increase in the volume of sessions during the pandemic months. The impacts of dialysis efficiency on patients and healthcare teams should be studied further, as should the influence of dialysis catheters and their design.
ABSTRACT
Introduction: Massive bleeding on extracorporeal membrane oxygenation (ECMO) is associated with multiple coagulation defects, including depletion of coagulation factors and development of acquired von Willebrand syndrome (AVWS). The use of recombinant factors, in particular recombinant activated factor VII (rFVIIa, Novoseven), to treat severe refractory hemorrhage in ECMO has been described. However, the use of multiple recombinant factors has been avoided in large part due to concern for circuit complications and thrombosis. Here, we describe the safe and effective administration of rFVIIa and recombinant von Willebrand factor complex (vWF/ FVIII, Humate-P) via post-oxygenator pigtail catheter on VA-ECMO for the treatment of massive pulmonary hemorrhage. Case Description: A 21-month-old (13.4 kg) girl with a recent history of COVID-19 infection presented to an outside hospital with parainfluenza bronchiolitis resulting in acute refractory hypoxemic respiratory failure (oxygenation index 58), refractory septic shock, and myocardial dysfunction. She was cannulated to VA-ECMO and subsequently diagnosed with necrotizing pneumonia from Pseudomonas and herpes simplex infections. Her course was complicated by a large left-sided pneumatocele and bronchopleural fistula requiring multiple chest tubes. She also had right mainstem bronchus obstruction from necrotic airway debris and complete right lung atelectasis. She was noted to have prolonged episodes of mucosal and cutaneous bleeding (oropharynx, chest tube insertion sites, peripheral IV insertion sites) associated with absent high molecular weight von Willebrand multimers consistent with AVWS. Tranexamic acid infusion was initiated and bivalirudin anticoagulation was discontinued. VA-ECMO flows were escalated to 140-160 ml/kg/min to maintain circuit integrity and meet high patient metabolic demand in the absence of anticoagulation. On ECMO day 26, she underwent bronchoscopy to clear necrotic debris from her airway to assist with lung recruitment. The procedure was notable for mucosal bleeding requiring topical epinephrine and rFVIIa. Post-procedure, she developed acute hemorrhage from her right mainstem bronchus, resulting in significant hemothorax (estimated 950 ml) with mediastinal shift, increased venous pressures, desaturation and decreased ECMO blood flow rate, necessitating massive transfusion of 2,050 ml (150 ml/kg) of packed red blood cells, platelets, plasma and cryoprecipitate. An airway blocker was placed in the mid-trachea to control bleeding. In addition to transfusion of appropriate blood products and continuation of tranexamic acid infusion, she was given both rFVIIa (100mcg/kg) and vWF-FVIII (70 units vWF/kg loading dose on the day of hemorrhage, followed by 40 units vWF/kg every 12 hours for 3 additional doses). Both products were administered over 10 minutes through a post-oxygenator pigtail to allow the product to circulate throughout the patient prior to entering the ECMO circuit. The circuit was closely monitored during administration and no changes to circuit integrity were noted in the subsequent hours while hemostasis was achieved. The ECMO circuit remained without thrombosis for 9 days after the bleeding event. Discussion: Balancing anticoagulation and hemostasis is a central challenge in maintaining ECMO support, especially given the prevalence of acquired coagulopathies such as AVWS. For our patient, AVWS contributed to mucosal bleeding necessitating cessation of anticoagulation and utilization of a high ECMO blood flow strategy to minimize circuit clot burden. This was further complicated by absent native lung function and minimal myocardial function, resulting in complete dependence on ECMO. An acute massive pulmonary hemorrhage was treated with multiple recombinant factors (rFVIIa and vWF/FVIII), that are often avoided on ECMO. To minimize clotting risk to the circuit and to maximize transit of these factors to our patient, we added a post-oxygenator pigtail for administration. While this approach was the result of extreme circumstances, th use of a post-oxygenator pigtail for administration of recombinant factors may represent a viable strategy for refractory hemorrhage while on ECMO.
ABSTRACT
Introduction: Continuous kidney replacement therapy (CKRT) offers more hemodynamic stability by permitting gradual removal of solute and fluid in critically ill adults. However the success of each CKRT session depends much on the hemofilter lifespan. Thus optimising hemofilter lifespan and performance efficiency in CKRT has been a focus in many studies over the years. The objective of this study is to look at the factors affecting hemofilter lifespan in critically ill adults with CKRT in our centre. Methods: A prospective observational study was conducted from 1st to 31stAugust 2021 in Intensive Care Unit (ICU), Hospital Selayang, Malaysia. Every CKRT sessions prescribed to critically ill adults (18 years and above) during the study period were included. Demographics of patient, biochemical results, CKRT prescriptions and lifespan of the hemofilter for each session were recorded. Results: Total of 46 patients were recruited with 51 sessions of CKRT performed. Male patients were 70.6%.Mean age was 44 ± 11 years. Almost half of the patients (49%) have underlying hypertension and 41% has diabetes. Majority were Covid-19 patients (92.2% ).Sepsis due to Covid-19 (82.4%) was main cause of ICU admission followed by other medical admission such as cardiogenic shock without Covid-19 (11.8%), surgical admission with Covid-19 (3.8%) and surgical admission without Covid-19 (2%). Indications for dialysis were refractory metabolic acidosis (56%),refractory hyperkalemia (24%) and fluid overload (20%). CKRT was performed due to severe shock (91.3%) and raised intracranial pressure (8.7%). Single inotrope was used in 84.3% of CKRT sessions and remaining had 2 or more inotropes (18%). Mean systolic blood pressure was 122 ± 16 mmHg. Anticoagulation used were heparin (70.6 %) and citrate ( 5.9%).No anticoagulation in remaining 23.5% sessions. Mean hemofilter lifespan was 30± 23 hours however death censored mean hemofilter lifespan was 40±22 hours. Hemofilter lasted less than 24 hours (mean 10± 4 hours) in 51% sessions, ≥ 24 hours but < 48 hours (mean 36± 7 hours) 25.4%, ≥48 hours but < 72 hours (mean 59±10 hours) 11.8% and 72 hours in 11.8% sessions (p= 0.005). The hemofilter lasted ≥24 hours when anticoagulant (heparin or citrate) is used compared to without anticoagulant (36±23 hours versus 9±3 hours;P = 0.005). Mean hemofilter lifespan among Covid-19 patients were longer compared to non Covid -19 patients ( 30±24 hours vs 24±18 hours, P=0.937).This maybe due to anticoagulant used in this group of patient as part of Covid-19 management. No significant differences in hemofilter life were found according to age, gender, comorbidity, diagnoses, hemofilter type, site of venous access, blood flow rate, filtration fraction,type of anticoagulant, inotropic drug support, haemoglobin,D Dimer,INR and platelet. Conclusions: Anticoagulants increase the hemofilter lifespan up to 40 hours in critically ill adults receiving continuous kidney replacement therapy. No conflict of interest
ABSTRACT
Vascular dysfunction and inflammation are precursors to cardiovascular disease (CVD). Notably, young adults who were symptomatic from COVID-19 during the acute phase of illness (within 4 weeks from diagnosis) have shown to exhibit peripheral vascular dysfunction. Importantly, many young adults report persistent symptoms from COVID-19 for several months, including cognitive difficulties. However, it remains unknown whether vascular dysfunction persists beyond the acute phase of COVID-19 in symptomatic young adults. We tested the hypothesis that peripheral and cerebral vascular function would be blunted in symptomatic (SYM) young adults who are beyond 4 weeks from a COVID-19 diagnosis, compared to asymptomatic adults (ASYM). Since COVID-19 causes inflammation that may negatively impact vascular function, we also hypothesized that serum hsCRP would be elevated in SYM compared to ASYM. We studied 15 otherwise healthy adults (age = 23 ± 1 years;mean ± SE) with a positive lab diagnosis of COVID-19. Eight were SYM (14 ± 1 weeks from diagnosis) while seven were ASYM (13 ± 2 weeks from diagnosis) at time of testing. Brachial artery flow-mediated dilation (FMD;duplex Doppler ultrasound) was performed, and macroand microvascular function were quantified as FMD% and peak blood velocity after cuff release, respectively. Cerebral vasomotor reactivity (CVMR) was quantified as percent increase in middle cerebral artery blood velocity (transcranial Doppler ultrasound) to rebreathing induced hypercapnia. Serum hsCRP level was measured. FMD was lower in SYM (3.81 ± 0.60%) compared to ASYM (7.10 ± 0.94%, P = 0.010). Likewise, peak blood velocity after cuff release was lower in SYM (47 ± 3 cm/s vs. ASYM: 65 ± 8 cm/s, P = 0.037). However, CVMR was not different between the two groups (P = 0.91). Serum hsCRP was higher in SYM (3.4 ± 1.0 mg/L vs. ASYM: 0.7 ± 0.1 mg/L, P = 0.036). These preliminary results indicate that peripheral macro-and microvascular function remain blunted beyond the acute phase in young adults with persistent symptoms from COVID-19, whereas cerebral vascular function appears unaffected. The extent to which this sustained vascular impairment and elevated hsCRP contributes to increased CVD risk in these otherwise healthy young adults remains to be determined.
ABSTRACT
Ischemia with No Obstructive Coronary Artery (INOCA) in angina patients increases the risk of major cardiac events, with a 1.5x increased mortality rate. There is a link between COVID-19 infection and impairment in the myocardial micro-vasculation which may cause an increase of INOCA patients. Fractional Flow Reserve (FFR), is the standard of care in cardiology but its diagnostic function is only related to Obstructive Coronary Artery disease (or epicardial) and it is ineffective with INOCA. The lack of effective and accurate tools for timely evaluation of coronary impairments creates a clinical unmet need. The PhysioCath catheter was developed within the Eurostars project FPCatheter, E!113577 aims to resolve this need a provide an effective tool to interventional cardiologists. The main project outcome is a catheter prototype equipped with a blood flow velocity sensor based on a thermo-convection principle, and a fiber optic pressure sensor (based on Fabry-Perot principle). While the use of Fabry-Perot type of sensor is already standard in the industry, the use of a thermo-convection sensor represents a progress with respect the state of the art. The sensor creates an overheat of 7°C above the physiological blood's temperature (considered as being within the safety limits), and it exchanges thermal power with the blood stream. The power is then measured and converted to velocity by means of a calibration curve. The project encompassed interviews with 14 clinical experts, the summary of the interviews indicated that the preferred form of the device is an over the wire microcatheter, with rapid exchange. Within the project then, it was developed a 3Fr microcatheter, with a rapid exchange section of 24cm. Both pressure sensor and flow velocity sensor were integrated in this embodiment. Finally, the PhysioCath prototype was evaluated in a bench test study. The test setup was composed by an anatomical silicone phantom of the aortic root and the coronaries (Elastrat, Geneva, Switzerland), perfused with a peristaltic pump (Harvard Apparatus, Holliston MA, US). The measurements performed by the flow velocity sensor were compared against and external doppler flow velocity sensor. While the pressure measurement was assessed for stability and presence of drift. The data processing revealed and extreme accuracy in the measurement of flow based indexes like CFR (±6% variability), accuracy of the blood flow velocity measurement (±10%), and extreme stability in the measurement of both pressure and flow velocity. In the second part of the project (that is currently ongoing), it will be studied the performance of the device within an animal setting. In conclusion, the PhysioCath device is a microcatheter integrating bot pressure measurement and blood flow velocity measurement. Its performance is of very high accuracy and stability, that represent a main step ahead with respect the current state of the art, based mainly on thermodilution.
ABSTRACT
Background/aim: Coronavirus 2019 disease (Covid-19) was first seen in December 2019 and afterwards it became pandemic. Several systemic involvements have been reported in Covid-19 patients. In this study, it was aimed to investigate the cerebrovascular hemodynamics in patients with Covid-19. Materials and methods: The sample of this study included 20 patients hospitalized in our clinic diagnosed with Covid-19 via PCR modality and 20 healthy volunteers of similar age and sex. Bilateral middle cerebral arteries were investigated with transcranial Doppler ultrasonography. Basal cerebral blood flow velocities and vasomotor reactivity rates were determined and statistically compared. Results: When patient and control groups were compared, the mean blood flow velocity was found to be higher in Covid-19 patients than in the healthy volunteers and it was statistically significant (P = 0.00). The mean vasomotor reactivity rates values were found to be lower in the Covid-19 group than the healthy group and was also statistically significant (P = 0.00). Conclusion: An increase in basal cerebral blood velocity and a decrease in vasomotor reactivity rates in patients with Covid-19 can be considered as an indicator of dysfunction of cerebral hemodynamics in the central nervous system and this can be evaluated as a result of endothelial dysfunction.