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1.
World J Pediatr Congenit Heart Surg ; 13(2): 235-241, 2022 03.
Article in English | MEDLINE | ID: mdl-35238708

ABSTRACT

PURPOSE: With newer generation diagonal and centrifugal blood pumps gaining popularity, the objective of this study was to compare the DP3-i-cor diagonal and RotaFlow centrifugal pumps in terms of hemodynamic performance using simulated neonatal and pediatric extracorporeal membrane oxygenation (ECMO) circuits. DESCRIPTION: The DP3-i-cor diagonal pump is a part of the newly FDA-approved NovaLung system. The experimental circuit consisted of either the DP3-i-cor diagonal or RotaFlow centrifugal pump, a polymethylpentene membrane oxygenator, neonatal and pediatric arterial/venous cannulae, and 1/4-inch ID tubing. Three circuits were tested using combinations of either the DP3-i-cor or RotaFlow pump and varying arterial/venous cannulae sizes. Real-time pressure and flow data were collected. EVALUATION: The new DP3-i-cor diagonal pump exhibited lower flow rate and pressure head when compared to the RotaFlow centrifugal pump at similar rotational speeds and identical experimental conditions. Large-caliber arterial cannulae expectedly generated higher flow rates and pressures. CONCLUSIONS: The RotaFlow centrifugal pump demonstrated superior hemodynamic performance when compared to the DP3-i-cor diagonal pump in simulated neonatal and pediatric ECMO circuits. Translational research of all ECMO components is crucial.


Subject(s)
Extracorporeal Membrane Oxygenation , Child , Equipment Design , Hemodynamics , Humans , Infant, Newborn , Models, Cardiovascular , Oxygenators, Membrane
2.
Heart Surg Forum ; 25(1): E140-E146, 2022 Feb 24.
Article in English | MEDLINE | ID: mdl-35238297

ABSTRACT

BACKGROUND: Extracorporeal membrane oxygenator (ECMO) has been implemented in refractory postcardiotomy cardiogenic shock (PCCS) patients to maintain excellent oxygenation and hemodynamic support. The aim of this study is to compare the results of early ECMO implantation to treat refractory PCCS in emergency versus elective patients who developed univentricular or biventricular pump failure. PATIENTS AND METHODS: Between January 2019 and June 2021, 35 patients received ECMO after refractory PCCS. Patients have been categorized into two groups: Group A contains 18 patients who were urgently operated on and Group B, which includes 17 patients who were electively operated on. ECMO was implanted through central cannulation (right atrium and ascending aorta), or through peripheral cannulation (femoral vessels or through axillary artery). RESULTS: There was no statistically significant difference between the two ECMO groups in the preoperative patient's characteristics, complication rate, duration of mechanical ventilation, post-ECMO weaning hospital stay, duration of ICU stay, in-hospital mortality, and number of patients discharged from the hospital or in 1-year survival on follow up. CONCLUSION: Early use of ECMO in high-risk emergency cardiac surgery should be taken into consideration when possible, without hesitance. Emergency and elective patients benefit equally from ECMO implantation and show comparable complication rates.


Subject(s)
Cardiac Surgical Procedures , Extracorporeal Membrane Oxygenation , Cardiac Surgical Procedures/adverse effects , Extracorporeal Membrane Oxygenation/methods , Humans , Oxygenators, Membrane/adverse effects , Prospective Studies , Retrospective Studies , Shock, Cardiogenic/etiology
3.
Int. j. artif. organs ; 45(1): 3-4, Jan. 2022.
Article in English | Sec. Est. Saúde SP, Sec. Est. Saúde SP, CONASS, SESSP-IDPCPROD, Sec. Est. Saúde SP | ID: biblio-1147026

ABSTRACT

It is established that coronaviruses are transmitted most through aerosols produced when an infected individual coughs or sneezes.1 Although there is no clear evidence of person-to-person airborne transmission, it is possible that part of this component could be due to microscopic respiratory droplets at short to medium distances (up to several meters, or room scale) and deposits from respiratory droplets on surfaces.2,3 However, recent studies revealed that infected patients can potentially be a source of the virus not only through respiratory but also fecal­oral or body fluid routes, raising also the theoretical possibility of bloodborne transmission.4 Based on these arguments, the possibility has also been raised of some equipment that could be a new source of transmission, like the membranes used for extracorporeal oxygenation, which act the same as lungs and also have a direct contact with the blood. Most centers worldwide report a reduction in the cardiac procedures due to the pandemic, however emergency surgeries with conventional cardiopulmonary bypass (CPB) and extracorporeal membrane oxygenation (ECMO) procedures have been performed every day. Despite guidelines and modifications for operating theatre preparation for the management of suspected or confirmed SARS-CoV-2 patients submitted to cardiac surgery, many aspects still need to be clarified.5 Potential risk of transmission with these membranes exists, so much that Dres et al.6 reported a study evaluating the risks of SARS-CoV-2 dissemination through membranes used for extra corporeal organ support in critically ill patients, within 48 h after ECMO and continuous renal replacement therapy (CRRT) initiation. They investigated whether SARS-CoV-2 RNA was detected in the dialysis effluent fluid or in the condensate collected from the ECMO membrane gas outlet, when the virus was present in the lower respiratory tract and the plasma. Results showed that in 25 patients on veno-venous ECMO, SARSCoV-2 RNA was not detected in the membrane oxygenator gas outlet condensate in any of 25 patients of whom 13 were plasma RNA positive. Also, they were not able to measure any SARS-CoV-2 RNA in the dialysate of those patients who additionally were treated by CRRT.


Subject(s)
Oxygenators, Membrane , Coronavirus , Aerosols , Membranes
4.
J Cardiovasc Transl Res ; 15(2): 268-278, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35075606

ABSTRACT

It is not well studied whether a secondary look by angiography (Re-Ang) after fixing the culprit lesion would be beneficial or not in cardiogenic shock (CS) supported by veno-arterial extracorporeal membrane oxygenator (VA-ECMO). This study was a retrospective observational one that looked at 5-year data from a single tertiary center. Patients were grouped according to the need of Re-Ang during the VA-ECMO course into 2 groups. The indications to perform Re-Ang were loss of pulse pressure, drop in ejection fraction or velocity time integral, resistant arrhythmia, or new electrocardiographic changes suggestive of ischemia. Out of 150 patients with cardiogenic shock screened, 30 patients were enrolled in our study. Re-Ang was done in 10 patients only. In 80% of them, positive findings were found in terms of new significant stenosis (3 patients), stent restenosis (1 patient), stent thrombosis (3 patients), and patent stent(s) with intervention to the remaining lesions in other vessels (1 patient). Neither successful weaning from VA-ECMO nor mortality was statistically different between both groups. Our set indications for Re-Ang were effective in finding a possible new culprit for a conceivable coronary intervention.


Subject(s)
Extracorporeal Membrane Oxygenation , Shock, Cardiogenic , Angiography , Extracorporeal Membrane Oxygenation/adverse effects , Humans , Oxygenators, Membrane , Retrospective Studies , Shock, Cardiogenic/diagnostic imaging , Shock, Cardiogenic/etiology
5.
Perfusion ; 37(2): 113-122, 2022 Mar.
Article in English | MEDLINE | ID: mdl-33349141

ABSTRACT

Therapeutic plasma exchange in children is increasingly recognized as a life-saving treatment and is challenged by some technical considerations. As extracorporeal membrane oxygenation has been used for nearly half a century for refractory reversible respiratory and/or cardiac failure in both pediatric and adult populations, it may serve as an extracorporeal platform for therapeutic plasma exchange. It is most commonly described in patients with sepsis with multiple organ failure or thrombocytopenia associated multi organ failure. Additional pathophysiological processes of inflammatory and immunological storms might benefit from the combination of extracorporeal membrane oxygenation and plasma exchange. This is a nonmethodological review of English-language reports of therapeutic plasma exchange performed in patients supported by extracorporeal membrane oxygenation, both pediatric and adult, searching six databases, MEDLINE, Clinical Key, GOOGLE SCHOLAR, CINAHL, Cochrane library, and EMBASE.


Subject(s)
Extracorporeal Membrane Oxygenation , Thrombocytopenia , Adult , Child , Extracorporeal Membrane Oxygenation/adverse effects , Humans , Multiple Organ Failure , Oxygenators, Membrane , Plasma Exchange/adverse effects , Thrombocytopenia/etiology
6.
ASAIO J ; 68(2): 281-286, 2022 02 01.
Article in English | MEDLINE | ID: mdl-34542991

ABSTRACT

The aim of this study was to evaluate the impact of pre-extracorporeal membrane oxygenation (ECMO) ventilatory parameters with in-hospital mortality in children with pediatric acute respiratory distress syndrome undergoing ECMO for respiratory indication. In this retrospective analysis of the Extracorporeal Life Support Organization (ELSO) Registry, all pediatric patients (≥29 days to ≤18 years) who required ECMO for respiratory indications were screened. The primary outcome was in-hospital mortality. From 2013 to 2017, 2,727 pediatric ECMO runs with a respiratory indication were reported to the ELSO registry. Overall mortality was 37%. Oxygenation Index (OI) and duration of mechanical ventilation (MV) before ECMO deployment were both independently associated with in-hospital mortality. No threshold effect for OI was observed. Pre-ECMO positive end-expiratory pressure and delta pressure levels were respectively lower and higher than recommended. Mortality rates for OI values between 4 and 60 and above oscillated between 32% and 45%. Children within a wider range of pre-ECMO OI (either below or above 40) might be considered as reasonable candidates for ECMO deployment. Larger, prospective multicenter studies to confirm the discriminatory ability of OI are warranted.


Subject(s)
Extracorporeal Membrane Oxygenation , Child , Hospital Mortality , Humans , Oxygenators, Membrane , Prospective Studies , Registries , Retrospective Studies
7.
J Card Surg ; 37(2): 437-439, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34741553

ABSTRACT

BACKGROUND: Left atrial venting through atrial septotomy in patients with decreased left ventricular (LV) contractility after venoarterial extracorporeal membrane oxygenation (VA-ECMO) is a simple and effective method for treating LV decompression. MATERIALS & METHODS: We report a case of prosthetic mitral valve thrombosis after left atrial venting in a patient with VA-ECMO. RESULTS: In patients undergoing mitral valve replacement, left atrial venting reduces the flow through the mitral valve and forms a prosthetic thrombosis. DISCUSSION: Therefore, excessive left atrial venting should be avoided. Other venting methods that can maintain the flow through the mitral valve should be considered after mitral valve replacement.


Subject(s)
Extracorporeal Membrane Oxygenation , Heart Valve Prosthesis , Thrombosis , Humans , Mitral Valve/diagnostic imaging , Mitral Valve/surgery , Oxygenators, Membrane , Thrombosis/etiology
8.
Ann Biomed Eng ; 49(12): 3636-3646, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34705123

ABSTRACT

Oxygenator thrombosis during extracorporeal membrane oxygenation (ECMO), is a complication that necessitates component replacement. ECMO centers monitor clot burden by intermittent measurement of pressure drop across the oxygenator. An increase in pressure drop at a preset flow rate suggests an increase in resistance/clot formation within the oxygenator. This monitoring method comes with inherent disadvantages such as monitoring gaps, and increased risk of air embolism and infection. We explored utilizing flow measurement, which avoids such risks, as an indicator of ECMO circuit obstructions. The hypothesis that flow rate through a shunt tube in the circuit will increase as distal resistances in the circuit increases was tested. We experimentally simulated controlled levels of oxygenator obstructions using glass microspheres in an ex vivo veno-venous ECMO circuit and measured the change in shunt flow rate using over the tube ultra-sound flow probes. A mathematical model was also used to study the effect of distal resistances in the ECMO circuit on shunt flow. Results of both the mathematical model and the experiments showed a clear and measurable increase in shunt flow with increasing levels of oxygenator obstruction. Therefore, flow monitoring appears to be an effective non-contact and continuous method to monitor for obstruction during ECMO.


Subject(s)
Extracorporeal Membrane Oxygenation/instrumentation , Oxygenators, Membrane , Blood Circulation , Equipment Failure , Extracorporeal Membrane Oxygenation/adverse effects , Humans , Models, Statistical , Oxygen/blood
9.
ACS Biomater Sci Eng ; 7(9): 4402-4419, 2021 09 13.
Article in English | MEDLINE | ID: mdl-34436868

ABSTRACT

Extracorporeal membrane oxygenation (ECMO) is used in critical care to manage patients with severe respiratory and cardiac failure. ECMO brings blood from a critically ill patient into contact with a non-endothelialized circuit which can cause clotting and bleeding simultaneously in this population. Continuous systemic anticoagulation is needed during ECMO. The membrane oxygenator, which is a critical component of the extracorporeal circuit, is prone to significant thrombus formation due to its large surface area and areas of low, turbulent, and stagnant flow. Various surface coatings, including but not limited to heparin, albumin, poly(ethylene glycol), phosphorylcholine, and poly(2-methoxyethyl acrylate), have been developed to reduce thrombus formation during ECMO. The present work provides an up-to-date overview of anti-thrombogenic surface coatings for ECMO, including both commercial coatings and those under development. The focus is placed on the coatings being developed for oxygenators. Overall, zwitterionic polymer coatings, nitric oxide (NO)-releasing coatings, and lubricant-infused coatings have attracted more attention than other coatings and showed some improvement in in vitro and in vivo anti-thrombogenic effects. However, most studies lacked standard hemocompatibility assessment and comparison studies with current clinically used coatings, either heparin coatings or nonheparin coatings. Moreover, this review identifies that further investigation on the thrombo-resistance, stability and durability of coatings under rated flow conditions and the effects of coatings on the function of oxygenators (pressure drop and gas transfer) are needed. Therefore, extensive further development is required before these new coatings can be used in the clinic.


Subject(s)
Extracorporeal Membrane Oxygenation , Thrombosis , Blood Coagulation , Heparin , Humans , Oxygenators, Membrane , Thrombosis/prevention & control
10.
Heart Lung ; 50(6): 853-856, 2021.
Article in English | MEDLINE | ID: mdl-34325183

ABSTRACT

A 34-year-old man developed severe hypoxemia and hypercapnia due to acute respiratory distress during ventilator care after surgery with acute intracranial hemorrhage. Severe hypoxemia had not been corrected even with maximum extracorporeal membrane oxygenation (ECMO) flow and full ventilator settings. We applied a novel technique for the serial connection of two veno-venous ECMO circuits for optimal oxygen delivery and CO2 removal and could wean VV ECMO. The use of serial connection of two VV ECMO circuits may be considered worthwhile when severe hypoxemia or hypercapnia are not improved and the use of protective ventilators is not permitted.


Subject(s)
Extracorporeal Membrane Oxygenation , Respiratory Distress Syndrome , Adult , Humans , Hypoxia/etiology , Male , Oxygenators, Membrane , Ventilators, Mechanical
11.
Comput Methods Programs Biomed ; 208: 106241, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34247118

ABSTRACT

While previous in vitro studies showed divergent results concerning the influence of pulsatile blood flow on oxygen advection in oxygenators, no study was done to investigate the uncertainty affected by blood flow dynamics. The aim of this study is to utilize a computational fluid dynamics model to clarify the debate concerning the influence of pulsatile blood flow on the oxygen transport. The computer model is based on a validated 2D finite volume approach that predicts oxygen transfer in pulsatile blood flow passing through a 300-micron hollow-fiber membrane bundle with a length of 254 mm, a building block for an artificial lung device. In this study, the flow parameters include the steady Reynolds number (Re = 2, 5, 10 and 20), Womersley parameter (Wo = 0.29, 0.38 and 0.53) and sinusoidal amplitude (A = 0.25, 0.5 and 0.75). Specifically, the computer model is extended to verify, for the first time, the previously measured O2 transport that was observed to be hindered by pulsating flow in the Biolung, developed by Michigan Critical Care Consultants. A comprehensive analysis is carried out on computed profiles and fields of oxygen partial pressure (PO2) and oxygen saturation (SO2) as a function of Re, Wo and A. Based on the present results, we observe the positive and negative effects of pulsatile flow on PO2 at different blood flow rates. Besides, the SO2 variation is not much influenced by the pulsatile flow conditions investigated. While being consistent with a recent experimental study, the computed O2 volume flow rate is found to be increased at high blood flow rates operated with low frequency and high amplitude. Furthermore, the present study qualitatively explains that divergent outcomes reported in previous in vitro experimental studies could be owing to the different blood flow rates adopted. Finally, the contour analysis reveals how the spatial distributions of PO2 and SO2 vary over time.


Subject(s)
Oxygen , Oxygenators, Membrane , Equipment Design , Humans , Hydrodynamics , Lung , Pulsatile Flow
12.
Heart Lung ; 50(6): 775-779, 2021.
Article in English | MEDLINE | ID: mdl-34217987

ABSTRACT

BACKGROUND: Post-traumatic stress disorder (PTSD) is a common long-term outcome after intensive care of critical illness. OBJECTIVES: Assess the prevalence and factors associated to PTSD after veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support. METHODS: Retrospective analysis of admission data and cross-sectional assessment of PTSD symptoms in adult survivors from admission requiring VA-ECMO support in a referral hospital. People were screened through abbreviated Impact of Event Scale-6 (IES-6). RESULTS: Out of 135 VA-ECMO implants performed from 2013 to 2020, 48 (35.6%) patients survived the admission. After a median follow-up of 31.4 [36] months, 34 survivors responded the questionnaire. All patients required sedation and invasive mechanical ventilation. Up to 29.4% of patients had PTSD symptoms. Patients with altered IES-6 items had passed a longer time since admission in ICCU (44±15 vs 30±20 months, p = 0.034). No baseline characteristic or admission-related variables were correlated with IES-6 except the lower time under mechanical ventilation (6.5 [8.5] vs. 8.5 [21] days, p = 0.044). CONCLUSIONS: Survivors from admission requiring VA-ECMO support show high prevalence of PTSD symptoms, appearing more frequently when more time has elapsed since admission. Special attention should be paid to psychological symptoms after VA-ECMO support.


Subject(s)
Extracorporeal Membrane Oxygenation , Stress Disorders, Post-Traumatic , Adult , Cross-Sectional Studies , Extracorporeal Membrane Oxygenation/adverse effects , Humans , Oxygenators, Membrane , Retrospective Studies , Stress Disorders, Post-Traumatic/epidemiology , Stress Disorders, Post-Traumatic/etiology
13.
Int J Artif Organs ; 44(5): 332-339, 2021 May.
Article in English | MEDLINE | ID: mdl-33949236

ABSTRACT

PURPOSE: Purpose: Condensation that clogs the hollow fibers of the oxygenation and accumulation of plasma leaks reduces oxygenated lung capacity. In this study, artificial We evaluated whether monitoring changes in lung gas inlet pressure was a way to predict these complications. METHODS: Changes in gas inlet pressure and oxygenation capacity of three different prostheses (BIOCUBE6000, EXCELUNG PRIME, and Capiox-LX) Evaluated the relationship. When simulating plasma leakage using BIOCUBE6000, sodium dodecyl sulfate (SDS) (1%, 0.1%, A solution of 0.01%, and RO water) reduced surface tension. During 120 minutes of circulation, changes in gas inlet pressure and leakage from the membrane into the gas flow path The amount of fluid was measured. RESULTS: There was a significant negative correlation between the gas inlet pressure changes and the oxygenation capacity of all three oxygenators (BIOCUBE6000: R2 = 0.957, EXCELUNG PRIME: R2 = 0.946, Capiox-LX: R2 = 0.878). After 120 min of SDS solution circulation using the BIOCUBE6000, both the gas inlet pressure and the volume of fluid leaking from the membrane into the gas flow path increased in proportion to the SDS solution concentration: RO water (0.56 ± 0.11 mmHg and 16.67 mL ± 0.94 mL), 0.01% SDS (0.98 ± 0.11 mmHg and 23.3 ± 0.47 mL,) 0.1% SDS (1.64 ± 0.21 mmHg and 29.0 ± 1.63 mL), and 1%SDS (14.3 ± 0.27 mmHg and 36.7 ± 0.47 mL) (n = 3). CONCLUSION: This study confirmed that monitoring the gas inlet pressure changes of an oxygenator during ECMO is clinically useful.


Subject(s)
Extracorporeal Membrane Oxygenation/methods , Oxygen/blood , Oxygenators, Membrane , Humans
14.
Int J Artif Organs ; 44(12): 938-943, 2021 Dec.
Article in English | MEDLINE | ID: mdl-33983071

ABSTRACT

The objective of this study was to determine if propofol administration to veno-venous (VV) extracorporeal membrane oxygenation (ECMO) patients was associated with more incidents of oxygenator failure when compared to patients who did not receive propofol. This was a single center, retrospective cohort study. The primary outcome of the study is oxygenator exchanges per ECMO day in patients who received propofol versus those who did not receive propofol. Patients were 18 years or older on VV-ECMO support between January 1, 2015 and January 31, 2018. Patients were excluded if they required ECMO support for less than 48 h or greater than 21 days. There were five patients in the propofol arm that required oxygenator exchanges and seven patients in the control arm. The total number of oxygenator exchanges per ECMO day was not significantly different between groups (p = 0.50). When comparing those who required an oxygenator exchange and those who did not, there was no difference in the cumulative dose of propofol received per ECMO hour (0.64 mg/kg/h vs 0.96 mg/kg/h; p = 0.16). Propofol use in patients on VV-ECMO does not appear to increase the number of oxygenator exchanges.


Subject(s)
Extracorporeal Membrane Oxygenation , Propofol/therapeutic use , Humans , Lung , Oxygenators, Membrane , Retrospective Studies
15.
J Artif Organs ; 24(3): 327-335, 2021 Sep.
Article in English | MEDLINE | ID: mdl-33677800

ABSTRACT

We aimed to analyze the outcome and identify predictors of hospital mortality in patients with refractory cardiac arrest (CA) complicating acute coronary syndromes (ACS) and requiring veno-arterial extracorporeal membrane oxygenation (VA-ECMO) treatment. Between Jan-2005 and Dec-2019, 51 patients underwent urgent VA-ECMO implantation for CA in ACS. Patients were divided in two groups: "in-hospital" cardiac arrest (IHCA) and "out-of-hospital" cardiac arrest (OHCA). Prospectively collected data were retrospectively analyzed and compared between groups. Predictors for hospital mortality were investigated. IHCA and OHCA patients were 32 (62.7%) and 19 (37.3%), respectively. The groups differed for: male gender (72% vs 95%; p = 0.070), lactate peak level (8.5 ± 4.3vs10.7 ± 2.9; p = 0.023), total elapsed time from CA to VA-ECMO implantation in both groups (p < 0.001) and elapsed time from CA (IHCA group) or hospital arrival (OHCA group) to VA-ECMO implantation (38 min vs 80 min; p = 0.001). At logistic regression analysis, concomitant lactate level greater than 8.0 mmol/L and elapsed time from CA to VA-ECMO ≥ 30 min were predictors of increased mortality (OR 3.9; 95% CI 1.19-12.79; p = 0.025) for the entire population. In-hospital mortality was 60.8% (31/51 patients): 68.4% in OHCA group and 56.2% in IHCA group. No risk factors related to 30-day mortality resulted significant at univariable analysis. When rapidly instituted, VA-ECMO improves survival in patients with refractory cardiac arrest allowing coronary syndrome treatment. The association of an elapsed time from CA to VA-ECMO implantation longer than 30 min and a preoperative lactate peak level over 8.0 mmol/L predict a poor outcome, independently from being IHCA or OHCA.


Subject(s)
Acute Coronary Syndrome , Cardiopulmonary Resuscitation , Out-of-Hospital Cardiac Arrest , Acute Coronary Syndrome/complications , Acute Coronary Syndrome/surgery , Hospital Mortality , Humans , Male , Oxygenators, Membrane , Retrospective Studies , Shock, Cardiogenic/etiology , Shock, Cardiogenic/therapy , Treatment Outcome
16.
PLoS One ; 16(3): e0248645, 2021.
Article in English | MEDLINE | ID: mdl-33735282

ABSTRACT

OBJECTIVE: Failure of membrane oxygenator (MO) function of venovenous extracorporeal membrane oxygenators (VV ECMO) remains problematic. The development of device-induced coagulation disorder (COD) or worsened gas transfer (WGT) necessitates a system exchange. The aim was to correlate von Willebrand factor antigen (vWF:Ag) with the predisposition to MO failure and mortality. METHODS: Laboratory parameters (inflammation, coagulation) and ECMO-related data from 31 VV ECMO patients were analyzed before and after the first MO exchange. Study groups were identified according to the exchange reasons (COD, WGT) and the extent of vWF:Ag (low, ≤425%; high, >425%). RESULTS: vWF:Ag remained unchanged after system exchange. High vWF:Ag was associated with systemic endothelial activation of older and obese patients with elevated SOFA score, increased norepinephrine and higher requirement of continuous renal replacement therapy without an effect on MO runtime and mortality. Including the mechanism of MO failure (COD, WGT), various patient group emerged. COD/low vWF:Ag summarized younger and less critically ill patients that benefit mainly from ECMO by a significant improvement of their inflammatory and coagulation status (CRP, D-dimers, fibrinogen) and highest survival rate (91%). Instead, WGT/high vWF:Ag presented older and more obese patients with a two-digit SOFA score, highest norepinephrine, and aggravated gas transfer. They benefited temporarily from system exchange but with worst survival (33%). CONCLUSIONS: vWF:Ag levels alone cannot predict early MO failure and outcome in VV ECMO patients. Probably, the mechanism of clotting disorder in combination with the vWF:Ag level seems to be essential for clot formation within the MO. In addition, vWF:Ag levels allows the identification different patient populations In particular, WGT/high vWF:Ag represented a critically ill population with higher ECMO-associated mortality.


Subject(s)
Acute Lung Injury/therapy , Equipment Failure/statistics & numerical data , Extracorporeal Membrane Oxygenation/adverse effects , Oxygenators, Membrane/adverse effects , Thrombosis/epidemiology , Acute Lung Injury/blood , Adult , Aged , Antigens/blood , Antigens/immunology , Blood Coagulation Tests/methods , Extracorporeal Membrane Oxygenation/instrumentation , Extracorporeal Membrane Oxygenation/statistics & numerical data , Female , Humans , Male , Middle Aged , Oxygenators, Membrane/statistics & numerical data , Retrospective Studies , Risk Assessment/methods , Risk Assessment/statistics & numerical data , Thrombosis/blood , Thrombosis/diagnosis , Thrombosis/etiology , Young Adult , von Willebrand Factor/immunology
17.
Artif Organs ; 45(8): E247-E264, 2021 Aug.
Article in English | MEDLINE | ID: mdl-33561881

ABSTRACT

Advances in microfluidics technologies have spurred the development of a new generation of microfluidic respiratory assist devices, constructed using microfabrication techniques capable of producing microchannel dimensions similar to those found in human capillaries and gas transfer films in the same thickness range as the alveolar membrane. These devices have been tested in laboratory settings and in some cases in extracorporeal animal experiments, yet none have been advanced to human clinical studies. A major challenge in the development of microfluidic oxygenators is the difficulty in scaling the technology toward high blood flows necessary to support adult humans; such scaling efforts are often limited by the complexity of the fabrication process and the manner in which blood is distributed in a three-dimensional network of microchannels. Conceptually, a central advantage of microfluidic oxygenators over existing hollow-fiber membrane-based configurations is the potential for shallower channels and thinner gas transfer membranes, features that reduce oxygen diffusion distances, to result in a higher gas transfer efficiency defined as the ratio of the volume of oxygen transferred to the blood per unit time to the active surface area of the gas transfer membrane. If this ratio is not significantly higher than values reported for hollow fiber membrane oxygenators (HFMO), then the expected advantage of the microfluidic approach would not be realized in practice, potentially due to challenges encountered in blood distribution strategies when scaling microfluidic designs to higher flow rates. Here, we report on scaling of a microfluidic oxygenator design from 4 to 92 mL/min blood flow, within an order of magnitude of the flow rate required for neonatal applications. This scaled device is shown to have a gas transfer efficiency higher than any other reported system in the literature, including other microfluidic prototypes and commercial HFMO cartridges. While the high oxygen transfer efficiency is a promising advance toward clinical scaling of a microfluidic architecture, it is accompanied by an excessive blood pressure drop in the circuit, arising from a combination of shallow gas transfer channels and equally shallow distribution manifolds. Therefore, next-generation microfluidic oxygenators will require novel design and fabrication strategies to minimize pressure drops while maintaining very high oxygen transfer efficiencies.


Subject(s)
Critical Care , Microfluidics/instrumentation , Oxygenators, Membrane , Equipment Design , Humans
18.
Clin Appl Thromb Hemost ; 27: 1076029620982374, 2021.
Article in English | MEDLINE | ID: mdl-33571008

ABSTRACT

Mechanically assisted circulation (MAC) sustains the blood circulation in the body of a patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) or on ventricular assistance with a ventricular assist device (VAD) or on extracorporeal membrane oxygenation (ECMO) with a pump-oxygenator system. While MAC provides short-term (days to weeks) support and long-term (months to years) for the heart and/or lungs, the blood is inevitably exposed to non-physiological shear stress (NPSS) due to mechanical pumping action and in contact with artificial surfaces. NPSS is well known to cause blood damage and functional alterations of blood cells. In this review, we discussed shear-induced platelet adhesion, platelet aggregation, platelet receptor shedding, and platelet apoptosis, shear-induced acquired von Willebrand syndrome (AVWS), shear-induced hemolysis and microparticle formation during MAC. These alterations are associated with perioperative bleeding and thrombotic events, morbidity and mortality, and quality of life in MCS patients. Understanding the mechanism of shear-induce hemostatic disorders will help us develop low-shear-stress devices and select more effective treatments for better clinical outcomes.


Subject(s)
Blood Platelets/metabolism , Cardiopulmonary Bypass/instrumentation , Extracorporeal Membrane Oxygenation/instrumentation , Heart-Assist Devices , Hemostatic Disorders/etiology , Oxygenators, Membrane , Prosthesis Implantation/instrumentation , Animals , Blood Platelets/pathology , Cardiopulmonary Bypass/adverse effects , Cell-Derived Microparticles/metabolism , Cell-Derived Microparticles/pathology , Extracorporeal Membrane Oxygenation/adverse effects , Hemolysis , Hemostatic Disorders/blood , Humans , Platelet Activation , Prosthesis Design , Prosthesis Implantation/adverse effects , Risk Assessment , Risk Factors , Stress, Mechanical , Treatment Outcome
19.
J Biomech Eng ; 143(5)2021 05 01.
Article in English | MEDLINE | ID: mdl-33462588

ABSTRACT

Extracorporeal membrane oxygenation (ECMO) has been used clinically for more than 40 years as a bridge to transplantation, with hollow-fiber membrane (HFM) oxygenators gaining in popularity due to their high gas transfer and low flow resistance. In spite of the technological advances in ECMO devices, the inevitable contact of the perfused blood with the polymer hollow-fiber gas-exchange membrane, and the subsequent thrombus formation, limits their clinical usage to only 2-4 weeks. In addition, the inhomogeneous flow in the device can further enhance thrombus formation and limit gas-transport efficiency. Endothelialization of the blood contacting surfaces of ECMO devices offers a potential solution to their inherent thrombogenicity. However, abnormal shear stresses and inhomogeneous blood flow might affect the function and activation status of the seeded endothelial cells (ECs). In this study, the blood flow through two HFM oxygenators, including the commercially available iLA® MiniLung Petite Novalung (Xenios AG, Germany) and an experimental one for the rat animal model, was modeled using computational fluid dynamics (CFD), with a view to assessing the magnitude and distribution of the wall shear stress (WSS) on the hollow fibers and flow fields in the oxygenators. This work demonstrated significant inhomogeneity in the flow dynamics of both oxygenators, with regions of high hollow-fiber WSS and regions of stagnant flow, implying a variable flow-induced stimulation on seeded ECs and possible EC activation and damage in a biohybrid oxygenator setting.


Subject(s)
Oxygenators, Membrane , Hydrodynamics
20.
ASAIO J ; 67(1): 12-17, 2021 01 01.
Article in English | MEDLINE | ID: mdl-32804773

ABSTRACT

Coronavirus disease (COVID-19) is overwhelming hospitals with patients requiring respiratory support, including ventilators and Extracorporeal Membrane Oxygenation (ECMO). Bottlenecks in device availability may contribute to mortality, and limited device availability even in ECMO centers has led to rationing recommendations. Therefore, we explored options for ad hoc construction of venovenous ECMO using readily available components, essentially, large cannulas, membrane oxygenators, and blood pumps. As thousands of certified cardiac Impella pumps are distributed worldwide, we assembled lean ECMO by embedding Impella pumps coaxially in tubes, combined with standard gas exchangers. Ad hoc integration of Impella blood pumps with gas exchange modules, large-bore venous cannulas, regular ECMO tubing, Y-pieces, and connectors led to lean ECMO systems with stable performance over several days. Oxygenation of 2.5-5 L of blood per minute is realistic. Benefit/risk analysis appears favorable if a patient needs respiratory support but required support systems in a center are exhausted. Ad hoc assembly of venovenous ECMO is feasible using Impella blood pumps, results in stable blood flow across gas exchange modules, and thus may offer another opportunity to oxygenate, "recover the lungs" and hopefully save lives in selected patients with severe COVID-19 disease even when conventional life support equipment is exhausted. The lean design also yields inspirations for future ECMO systems.


Subject(s)
COVID-19/therapy , Extracorporeal Membrane Oxygenation/instrumentation , Extracorporeal Membrane Oxygenation/methods , Oxygenators, Membrane , Equipment Design , Hemodynamics , Humans , Oxygen , Risk
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