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1.
Crit Care ; 25(1): 199, 2021 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-34108029

RESUMO

BACKGROUND: Heterogeneous respiratory system static compliance (CRS) values and levels of hypoxemia in patients with novel coronavirus disease (COVID-19) requiring mechanical ventilation have been reported in previous small-case series or studies conducted at a national level. METHODS: We designed a retrospective observational cohort study with rapid data gathering from the international COVID-19 Critical Care Consortium study to comprehensively describe CRS-calculated as: tidal volume/[airway plateau pressure-positive end-expiratory pressure (PEEP)]-and its association with ventilatory management and outcomes of COVID-19 patients on mechanical ventilation (MV), admitted to intensive care units (ICU) worldwide. RESULTS: We studied 745 patients from 22 countries, who required admission to the ICU and MV from January 14 to December 31, 2020, and presented at least one value of CRS within the first seven days of MV. Median (IQR) age was 62 (52-71), patients were predominantly males (68%) and from Europe/North and South America (88%). CRS, within 48 h from endotracheal intubation, was available in 649 patients and was neither associated with the duration from onset of symptoms to commencement of MV (p = 0.417) nor with PaO2/FiO2 (p = 0.100). Females presented lower CRS than males (95% CI of CRS difference between females-males: - 11.8 to - 7.4 mL/cmH2O p < 0.001), and although females presented higher body mass index (BMI), association of BMI with CRS was marginal (p = 0.139). Ventilatory management varied across CRS range, resulting in a significant association between CRS and driving pressure (estimated decrease - 0.31 cmH2O/L per mL/cmH20 of CRS, 95% CI - 0.48 to - 0.14, p < 0.001). Overall, 28-day ICU mortality, accounting for the competing risk of being discharged within the period, was 35.6% (SE 1.7). Cox proportional hazard analysis demonstrated that CRS (+ 10 mL/cm H2O) was only associated with being discharge from the ICU within 28 days (HR 1.14, 95% CI 1.02-1.28, p = 0.018). CONCLUSIONS: This multicentre report provides a comprehensive account of CRS in COVID-19 patients on MV. CRS measured within 48 h from commencement of MV has marginal predictive value for 28-day mortality, but was associated with being discharged from ICU within the same period. Trial documentation: Available at https://www.covid-critical.com/study . TRIAL REGISTRATION: ACTRN12620000421932.


Assuntos
COVID-19/complicações , COVID-19/terapia , Complacência Pulmonar/fisiologia , Respiração Artificial/métodos , Síndrome do Desconforto Respiratório/etiologia , Síndrome do Desconforto Respiratório/terapia , Adulto , Estudos de Coortes , Cuidados Críticos/métodos , Europa (Continente) , Feminino , Humanos , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Índice de Gravidade de Doença
2.
BMC Med Ethics ; 22(1): 70, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-34074282

RESUMO

BACKGROUND: ECMO is a particularly scarce resource during the COVID-19 pandemic. Its allocation involves ethical considerations that may be different to usual times. There is limited pre-pandemic literature on the ethical factors that ECMO physicians consider during ECMO allocation. During the pandemic, there has been relatively little professional guidance specifically relating to ethics and ECMO allocation; although there has been active ethical debate about allocation of other critical care resources. We report the results of a small international exploratory survey of ECMO clinicians' views on different patient factors in ECMO decision-making prior to and during the COVID-19 pandemic. We then outline current ethical decision procedures and recommendations for rationing life-sustaining treatment during the COVID-19 pandemic, and examine the extent to which current guidelines for ECMO allocation (and reported practice) adhere to these ethical guidelines and recommendations. METHODS: An online survey was performed with responses recorded between mid May and mid August 2020. Participants (n = 48) were sourced from the ECMOCard study group-an international group of experts (n = 120) taking part in a prospective international study of ECMO and intensive care for patients during the COVID-19 pandemic. The survey compared the extent to which certain ethical factors involved in ECMO resource allocation were considered prior to and during the pandemic. RESULTS: When initiating ECMO during the pandemic, compared to usual times, participants reported giving more ethical weight to the benefit of ECMO to other patients not yet admitted as opposed to those already receiving ECMO, (p < 0.001). If a full unit were referred a good candidate for ECMO, participants were more likely during the pandemic to consider discontinuing ECMO from a current patient with low chance of survival (53% during pandemic vs. 33% prior p = 0.002). If the clinical team recommends that ECMO should cease, but family do not agree, the majority of participants indicated that they would continue treatment, both in usual circumstances (67%) and during the pandemic (56%). CONCLUSIONS: We found differences during the COVID-19 pandemic in prioritisation of several ethical factors in the context of ECMO allocation. The ethical principles prioritised by survey participants were largely consistent with ECMO allocation guidelines, current ethical decision procedures and recommendations for allocation of life-sustaining treatment during the COVID-19 pandemic.

3.
Shock ; 2021 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-34014886

RESUMO

BACKGROUND: Aggressive fluid or blood component transfusion for severe haemorrhagic shock may restore macrocirculatory parameters, but not always improve microcirculatory perfusion and tissue oxygen delivery. We established an ovine model of haemorrhagic shock to systematically assess tissue oxygen delivery and repayment of oxygen debt; appropriate outcomes to guide patient blood management. METHODS: Female Dorset-cross sheep were anaesthetised, intubated, and subjected to comprehensive macrohaemodynamic, regional tissue oxygen saturation (StO2), sublingual capillary imaging and arterial lactate monitoring, confirmed by invasive organ-specific microvascular perfusion, oxygen pressure and lactate/pyruvate levels, in brain, kidney, liver and skeletal muscle. Shock was induced by stepwise withdrawal of venous blood until mean arterial pressure (MAP) was 30mmHg, mixed venous oxygen saturation (SvO2) < 60%, and arterial lactate >4 mM. Resuscitation with PlasmaLyte® was dosed to achieve MAP > 65mmHg. RESULTS: Haemorrhage impacted primary outcomes between baseline and development of shock: MAP 89 ±â€Š5 to 31 ±â€Š5 mmHg (p < 0.01), SvO2 70 ±â€Š7 to 23 ±â€Š8% (p < 0.05), cerebral regional tissue oxygen saturation (StO2) 77 ±â€Š11 to 65 ±â€Š9% (p < 0.01), peripheral muscle StO2 66 ±â€Š8 to 16 ±â€Š9% (p < 0.01), arterial lactate 1.5 ±â€Š1.0 to 5.1 ±â€Š0.8 mM (p < 0.01), and base excess 1.1 ±â€Š2.2 to -3.6 ±â€Š1.7 mM (p < 0.05). Invasive organ-specific monitoring confirmed reduced tissue oxygen delivery; oxygen tension decreased and lactate increased in all tissues, but moderately in brain. Blood volume replacement with PlasmaLyte® improved primary outcome measures toward baseline, confirmed by organ-specific measures, despite haemoglobin reduced from baseline 10.8 ±â€Š1.2 to 5.9 ±â€Š1.1 g/dl post-resuscitation (p < 0.01). CONCLUSION: Non-invasive measures of tissue oxygen delivery and oxygen debt repayment are suitable outcomes to inform Patient Blood Management of haemorrhagic shock, translatable for pre-clinical assessment of novel resuscitation strategies.

4.
Lancet ; 397(10283): 1447-1458, 2021 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-33865494

RESUMO

BACKGROUND: The optimal duration of infusion set use to prevent life-threatening catheter-related bloodstream infection (CRBSI) is unclear. We aimed to compare the effectiveness and costs of 7-day (intervention) versus 4-day (control) infusion set replacement to prevent CRBSI in patients with central venous access devices (tunnelled cuffed, non-tunnelled, peripherally inserted, and totally implanted) and peripheral arterial catheters. METHODS: We did a randomised, controlled, assessor-masked trial at ten Australian hospitals. Our hypothesis was CRBSI equivalence for central venous access devices and non-inferiority for peripheral arterial catheters (both 2% margin). Adults and children with expected greater than 24 h central venous access device-peripheral arterial catheter use were randomly assigned (1:1; stratified by hospital, catheter type, and intensive care unit or ward) by a centralised, web-based service (concealed before allocation) to infusion set replacement every 7 days, or 4 days. This included crystalloids, non-lipid parenteral nutrition, and medication infusions. Patients and clinicians were not masked, but the primary outcome (CRBSI) was adjudicated by masked infectious diseases physicians. The analysis was modified intention to treat (mITT). This study is registered with the Australian New Zealand Clinical Trials Registry ACTRN12610000505000 and is complete. FINDINGS: Between May 30, 2011, and Dec, 9, 2016, from 6007 patients assessed, we assigned 2944 patients to 7-day (n=1463) or 4-day (n=1481) infusion set replacement, with 2941 in the mITT analysis. For central venous access devices, 20 (1·78%) of 1124 patients (7-day group) and 16 (1·46%) of 1097 patients (4-day group) had CRBSI (absolute risk difference [ARD] 0·32%, 95% CI -0·73 to 1·37). For peripheral arterial catheters, one (0·28%) of 357 patients in the 7-day group and none of 363 patients in the 4-day group had CRBSI (ARD 0·28%, -0·27% to 0·83%). There were no treatment-related adverse events. INTERPRETATION: Infusion set use can be safely extended to 7 days with resultant cost and workload reductions. FUNDING: Australian National Health and Medical Research Council.

5.
Pharmacol Res ; 169: 105631, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33905863

RESUMO

BACKGROUND: Heart failure is an inexorably progressive disease with a high mortality, for which heart transplantation (HTx) remains the gold standard treatment. Currently, donor hearts are primarily derived from patients following brain stem death (BSD). BSD causes activation of the sympathetic nervous system, increases endothelin levels, and triggers significant inflammation that together with potential myocardial injury associated with the transplant procedure, may affect contractility of the donor heart. We examined peri-transplant myocardial catecholamine sensitivity and cardiac contractility post-BSD and transplantation in a clinically relevant ovine model. METHODS: Donor sheep underwent BSD (BSD, n = 5) or sham (no BSD) procedures (SHAM, n = 4) and were monitored for 24h prior to heart procurement. Orthotopic HTx was performed on a separate group of donor animals following 24h of BSD (BSD-Tx, n = 6) or SHAM injury (SH-Tx, n = 5). The healthy recipient heart was used as a control (HC, n = 11). A cumulative concentration-effect curve to (-)-noradrenaline (NA) was established using left (LV) and right ventricular (RV) trabeculae to determine ß1-adrenoceptor mediated potency (-logEC50 [(-)-noradrenaline] M) and maximal contractility (Emax). RESULTS: Our data showed reduced basal and maximal (-)-noradrenaline induced contractility of the RV (but not LV) following BSD as well as HTx, regardless of whether the donor heart was exposed to BSD or SHAM. The potency of (-)-noradrenaline was lower in left and right ventricles for BSD-Tx and SH-Tx compared to HC. CONCLUSION: These studies show that the combination of BSD and transplantation are likely to impair contractility of the donor heart, particularly for the RV. For the donor heart, this contractile dysfunction appears to be independent of changes to ß1-adrenoceptor sensitivity. However, altered ß1-adrenoceptor signalling is likely to be involved in post-HTx contractile dysfunction.

6.
ASAIO J ; 67(4): 416-422, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33769996

RESUMO

This study investigated the accuracy of the HeartWare HVAD flow estimator for left ventricular assist device (LVAD) support and biventricular assist device (BiVAD) support for modes of reduced speed (BiVAD-RS) and banded outflow (BiVAD-B). The HVAD flow estimator was evaluated in a mock circulatory loop under changes in systemic and pulmonary vascular resistance, heart rate, central venous pressure, and simulated hematocrit (correlated to viscosity). A difference was found between mean estimated and mean measured flow for LVAD (0.1 ± 0.3 L/min), BiVAD-RS (-0.1 ± 0.2 L/min), and BiVAD-B (0 ± 0.2 L/min). Analysis of the flow waveform pulsatility showed good correlation for LVAD (r2 = 0.98) with a modest spread in error (0.7 ± 0.1 L/min), while BiVAD-RS and BiVAD-B showed similar spread in error (0.7 ± 0.3 and 0.7 ± 0.2 L/min, respectively), with much lower correlation (r2 = 0.85 and r2 = 0.60, respectively). This study demonstrated that the mean flow error of the HVAD flow estimator is similar when the device is used in LVAD, BiVAD-RS, or BiVAD-B configuration. However, the instantaneous flow waveform should be interpreted with caution, particularly in the cases of BiVAD support.


Assuntos
Coração Auxiliar , Hemodinâmica/fisiologia , Modelos Cardiovasculares , Disfunção Ventricular Esquerda/fisiopatologia , Feminino , Insuficiência Cardíaca/fisiopatologia , Insuficiência Cardíaca/terapia , Ventrículos do Coração/fisiopatologia , Humanos , Masculino , Estudos Retrospectivos , Disfunção Ventricular Esquerda/terapia , Disfunção Ventricular Direita/fisiopatologia , Disfunção Ventricular Direita/terapia
7.
Transplantation ; 105(3): 496-508, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33617201

RESUMO

Primary graft dysfunction is an important cause of morbidity and mortality after cardiac transplantation. Donor brain stem death (BSD) is a significant contributor to donor heart dysfunction and primary graft dysfunction. There remain substantial gaps in the mechanistic understanding of peritransplant cardiac dysfunction. One of these gaps is cardiac metabolism and metabolic function. The healthy heart is an "omnivore," capable of utilizing multiple sources of nutrients to fuel its enormous energetic demand. When this fails, metabolic inflexibility leads to myocardial dysfunction. Data have hinted at metabolic disturbance in the BSD donor and subsequent heart transplantation; however, there is limited evidence demonstrating specific metabolic or mitochondrial dysfunction. This review will examine the literature surrounding cardiometabolic and mitochondrial function in the BSD donor, organ preservation, and subsequent cardiac transplantation. A more comprehensive understanding of this subject may then help to identify important cardioprotective strategies to improve the number and quality of donor hearts.

8.
ASAIO J ; 67(3): 270-275, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33627600

RESUMO

The development of adult use right ventricular assist devices (RVADs) and pediatric left ventricular assist devices (pediatric LVADs) have significantly lagged behind compared to adult use left ventricular assist devices (LVADs). The HeartWare ventricular assist device (HVAD) intended to be used for adult's systemic support, is increasingly used off-label for adult pulmonary and pediatric systemic support. Due to different hemodynamics and physiology, however, the HVAD's hemocompatibility profiles can be drastically different when used in adult pulmonary circulation or in children, compared to its intended usage state, which could have a direct clinical and developmental relevance. Taking these considerations in mind, we sought to conduct in vitro hemocompatibility testing of HVAD in adult systemic, pediatric systemic and adult pulmonary support conditions. Two HVADs coupled to custom-built blood circulation loops were tested for 6 hours using bovine blood at 37°C under adult systemic, pediatric systemic, and adult pulmonary flow conditions (flow rate = 5.0, 2.5, and 4.5 L/min; differential pressure = 100, 69, and 20 mm Hg, respectively). Normalized index of hemolysis for adult systemic, pediatric systemic, and adult pulmonary conditions were 0.0083, 0.0039, and 0.0017 g/100 L, respectively. No significant difference was seen in platelet activation for these given conditions. High molecular weight von Willebrand factor multimer degradation was evident in all conditions (p < 0.05). In conclusion, alterations in the usage mode produce substantial differences in hemocompatibility of the HVAD. These findings would not only have clinical relevance but will also facilitate future adult use RVAD and pediatric LVAD development.


Assuntos
Coração Auxiliar , Teste de Materiais , Modelos Cardiovasculares , Adulto , Animais , Bovinos , Criança , Feminino , Coração Auxiliar/efeitos adversos , Humanos , Técnicas In Vitro , Masculino
9.
Intensive Care Med Exp ; 9(1): 5, 2021 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-33502631

RESUMO

BACKGROUND: Extracorporeal membrane oxygenation (ECMO), an invasive mechanical therapy, provides cardio-respiratory support to critically ill patients when maximal conventional support has failed. ECMO is delivered via large-bore cannulae which must be effectively secured to avoid complications including cannula migration, dislodgement and accidental decannulation. Growing evidence suggests tissue adhesive (TA) may be a practical and safe method to secure vascular access devices, but little evidence exists pertaining to securement of ECMO cannulae. The aim of this study was to determine the safety and efficacy of two TA formulations (2-octyl cyanoacrylate and n-butyl-2-octyl cyanoacrylate) for use in peripherally inserted ECMO cannula securement, and compare TA securement to 'standard' securement methods. METHODS: This in vitro project assessed: (1) the tensile strength and flexibility of TA formulations compared to 'standard' ECMO cannula securement using a porcine skin model, and (2) the chemical resistance of the polyurethane ECMO cannulae to TA. An Instron 5567 Universal Testing System was used for strength testing in both experiments. RESULTS: Securement with sutures and n-butyl-2-octyl cyanoacrylate both significantly increased the force required to dislodge the cannula compared to a transparent polyurethane dressing (p = 0.006 and p = 0.003, respectively) and 2-octyl cyanoacrylate (p = 0.023 and p = 0.013, respectively). Suture securement provided increased flexibility compared to TA securement (p < 0.0001), and there was no statistically significant difference in flexibility between 2-octyl cyanoacrylate and n-butyl-2-octyl cyanoacrylate (p = 0.774). The resistance strength of cannula polyurethane was not weakened after exposure to either TA formulation after 60 min compared to control. CONCLUSIONS: Tissue adhesive appears to be a promising adjunct method of ECMO cannula insertion site securement. Tissue adhesive securement with n-butyl-2-octyl cyanoacrylate may provide comparable securement strength to a single polypropylene drain stitch, and, when used as an adjunct securement method, may minimise the risks associated with suture securement. However, further clinical research is still needed in this area.

10.
Anaesth Intensive Care ; 49(2): 105-111, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33504171

RESUMO

The COVID-19 pandemic has required intensive care units to rapidly adjust and adapt their existing practices. Although there has a focus on expanding critical care infrastructure, equipment and workforce, plans have not emphasised the need to increase digital capabilities. The objective of this report was to recognise key areas of digital health related to the COVID-19 response. We identified and explored six focus areas relevant to intensive care, including using digital solutions to increase critical care capacity, developing surge capacity within an electronic health record, maintenance and downtime planning, training considerations and the role of data analytics. This article forms the basis of a framework for the intensive care digital health response to COVID-19 and other emerging infectious disease outbreaks.


Assuntos
COVID-19 , Cuidados Críticos , Surtos de Doenças , Humanos , Pandemias , SARS-CoV-2
11.
BMJ Open ; 10(12): e041417, 2020 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-33268426

RESUMO

INTRODUCTION: There is a paucity of data that can be used to guide the management of critically ill patients with COVID-19. In response, a research and data-sharing collaborative-The COVID-19 Critical Care Consortium-has been assembled to harness the cumulative experience of intensive care units (ICUs) worldwide. The resulting observational study provides a platform to rapidly disseminate detailed data and insights crucial to improving outcomes. METHODS AND ANALYSIS: This is an international, multicentre, observational study of patients with confirmed or suspected SARS-CoV-2 infection admitted to ICUs. This is an evolving, open-ended study that commenced on 1 January 2020 and currently includes >350 sites in over 48 countries. The study enrols patients at the time of ICU admission and follows them to the time of death, hospital discharge or 28 days post-ICU admission, whichever occurs last. Key data, collected via an electronic case report form devised in collaboration with the International Severe Acute Respiratory and Emerging Infection Consortium/Short Period Incidence Study of Severe Acute Respiratory Illness networks, include: patient demographic data and risk factors, clinical features, severity of illness and respiratory failure, need for non-invasive and/or mechanical ventilation and/or extracorporeal membrane oxygenation and associated complications, as well as data on adjunctive therapies. ETHICS AND DISSEMINATION: Local principal investigators will ensure that the study adheres to all relevant national regulations, and that the necessary approvals are in place before a site may contribute data. In jurisdictions where a waiver of consent is deemed insufficient, prospective, representative or retrospective consent will be obtained, as appropriate. A web-based dashboard has been developed to provide relevant data and descriptive statistics to international collaborators in real-time. It is anticipated that, following study completion, all de-identified data will be made open access. TRIAL REGISTRATION NUMBER: ACTRN12620000421932 (http://anzctr.org.au/ACTRN12620000421932.aspx).

13.
Int J Antimicrob Agents ; : 106232, 2020 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-33232733

RESUMO

BACKGROUND: Ventilator associated pneumonia occurs commonly and nebulized antibiotics are being used for its treatment. Although adequate pulmonary biodistribution is important for antibiotic effect, there is a lack of data for both intravenous (i.v.) or nebulized antibiotic administration during mechanical ventilation. OBJECTIVE: To describe the comparative pulmonary regional distribution of i.v. and nebulized technetium-99m labelled tobramycin (99mTc-tobramycin) 400 mg in a mechanically ventilated ovine model. METHODS: The study was performed in a mechanically ventilated ovine model. 99mTc-tobramycin 400 mg was obtained using a radiolabelling process. Computed tomography (CT) was performed. Five sheep each were given 99mTc-tobramycin 400 mg via i.v. or nebulized route. Planar images- dorsal, ventral and both lateral- were obtained using a gamma camera. Blood samples were obtained every 15 minutes for one hour (4 time points) and, lung, liver, both kidney, and urine samples were obtained post mortem. RESULTS: Ten sheep were anesthetized and mechanically ventilated. Whole lung deposition of nebulized 99mTc-tobramycin 400 mg was significantly lower than with i.v. (8.8 vs 57.1%, p<0.001). For both administration routes, upper lung zones had a significantly lower deposition than the rest of the lungs. Dorsal deposition was significantly higher with nebulized 99mTc-tobramycin 400 mg compared to i.v. (68.9 vs 58.9%, p=0.003). The lung concentrations of 99mTc-tobramycin were higher with i.v. compared to nebulized. There were significantly higher concentrations of 99mTc-tobramycin in blood, liver and urine with i.v. administration compared to nebulized. CONCLUSIONS: Nebulization resulted in lower whole and regional lung deposition of 99mTc-tobramycin and also appears associated with low blood and extra-pulmonary organ concentrations.

15.
Intensive Care Med ; 46(12): 2464-2476, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33140180

RESUMO

Extracorporeal life support (ECLS) can support gas exchange in patients with the acute respiratory distress syndrome (ARDS). During ECLS, venous blood is drained from a central vein via a cannula, pumped through a semipermeable membrane that permits diffusion of oxygen and carbon dioxide, and returned via a cannula to a central vein. Two related forms of ECLS are used. Venovenous extracorporeal membrane oxygenation (ECMO), which uses high blood flow rates to both oxygenate the blood and remove carbon dioxide, may be considered in patients with severe ARDS whose oxygenation or ventilation cannot be maintained adequately with best practice conventional mechanical ventilation and adjunctive therapies, including prone positioning. Extracorporeal carbon dioxide removal (ECCO2R) uses lower blood flow rates through smaller cannulae and provides substantial CO2 elimination (~ 20-70% of total CO2 production), albeit with marginal improvement in oxygenation. The rationale for using ECCO2R in ARDS is to facilitate lung-protective ventilation by allowing a reduction of tidal volume, respiratory rate, plateau pressure, driving pressure and mechanical power delivered by the mechanical ventilator. This narrative review summarizes physiological concepts related to ECLS, as well as the rationale and evidence supporting ECMO and ECCO2R for the treatment of ARDS. It also reviews complications, limitations, and the ethical dilemmas that can arise in treating patients with ECLS. Finally, it discusses future key research questions and challenges for this technology.

16.
Crit Care ; 24(1): 650, 2020 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-33213485
17.
Vox Sang ; 2020 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-33107065

RESUMO

BACKGROUND AND OBJECTIVES: Sheep are increasingly being used as a large in vivo animal model of blood transfusion because they provide several advantages over small animals. Understanding the effects of storage duration on ovine (ov) red cell concentrates (RCCs) and how these changes compare with stored human (hu) RCCs is necessary to facilitate clinical translation of research findings. MATERIALS AND METHODS: OvRCCs (n = 5) collected and processed in standard human blood collection packs, and equivalent huRCCs provided by Australian Red Cross Lifeblood (n = 5), were stored at 2-6°C for 42 days, with samples collected weekly. Haemolysis index was determined by measuring supernatant haemoglobin concentration. Biochemical parameters were evaluated using a blood gas analyser. Energy metabolites and biologically active lipids were measured using commercial assays. Osmotic fragility was determined by lysis in various saline concentrations. Extracellular vesicles were characterized by nanoparticle tracking analysis. RESULTS: Ovine red blood cells (RBCs) are double in number, smaller in size and more fragile than human RBCs. Haematological values were unchanged throughout storage. In contrast, biochemical and metabolic values, and haemolysis index in three of the five ovRCCs exceeded huRCCs licensing criteria by day 42. Accumulation of extracellular vesicles and biologically active lipids was comparable between huRCCs and ovRCCs. CONCLUSION: This study documents similarities and differences in the storage lesion of ovRCCs and huRCCs. This new information will guide the design of ovine transfusion models to enhance translation of findings to human transfusion settings.

18.
Aust Crit Care ; 2020 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-32943306

RESUMO

BACKGROUND: The intensive care environment and experiences during admission can negatively impact patient and family outcomes and can complicate recovery both in hospital and after discharge. While their perspectives based on intimate experiences of the environment could help inform design improvements, patients and their families are typically not involved in design processes. Rather than designing the environment around the needs of the patients, emphasis has traditionally been placed on clinical and economic efficiencies. OBJECTIVE: The main objective was to inform design of an optimised intensive care bedspace by developing an understanding of how patients and their families experience the intensive care environment and its impact on recovery. METHODS: A qualitative descriptive study was conducted with data collected in interviews with 17 intensive care patients and seven family members at a large cardiothoracic specialist hospital, analysed using a framework approach. RESULTS: Participants described the intensive care as a noisy, bright, confronting and scary environment that prevented sleep and was suboptimal for recovery. Bedspaces were described as small and cluttered, with limited access to natural light or cognitive stimulation. The limited ability to personalise the environment and maintain connections with family and the outside world was considered especially problematic. CONCLUSIONS: Intensive care patients described features of the current environment they considered problematic and potentially hindering their recovery. The perspective of patients and their families can be utilised by researchers and developers to improve the design and function of the intensive care environment. This can potentially improve patient outcomes and help deliver more personalised and effective care to this vulnerable patient population and their families.

20.
Artif Organs ; 2020 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-32866998

RESUMO

Limb ischemia is a major complication associated with peripheral venoarterial extracorporeal membrane oxygenation (VA-ECMO). The high velocity jet from arterial cannulae can cause "sandblasting" injuries to the arterial endothelium, with the potential risk of distal embolization and end organ damage. The aim of this study was to identify, for a range of clinically relevant VA-ECMO cannulae and flow rates, any regions of peak flow velocity on the aortic wall which may predispose to vascular injury, and any regions of low-velocity flow which may predispose to thrombus formation. A silicone model of the aortic and iliac vessels was sourced and the right external iliac artery was cannulated. Cannulae ranged from 15 to 21 Fr in size. Simulated steady state ECMO flow rates were instituted using a magnetically levitated pump (CentriMag pump). Adaptive particle image velocimetry was performed for each cannula at 3, 3.5, 4, and 4.5 L/min. For all cannulae, in both horizontal and vertical side hole orientations, the peak velocity on the aortic wall ranged from 0.3 to 0.45 m/s, and the regions of lowest velocity flow were 0.05 m/s. The magnitude of peak velocity flow on the aortic wall was not different between a single pair versus multiple pairs of side holes. Maximum velocity flow on the aortic wall occurred earlier at a lower pump flow rate in the vertical orientation of distal side holes compared to a horizontal position. The presence of multiple paired side holes was associated with fewer low-velocity flow regions, and some retrograde flow, in the distal abdominal aorta compared to cannulae with a single pair of side holes. From this in vitro visualization study, the selection of a cannula design with multiple versus single pairs of side holes did not change the magnitude of peak velocity flow delivered to the vessel wall. Cannulae with multiple side holes were associated with fewer regions of low-velocity flow in the distal abdominal aorta. Further in vivo studies, and ideally clinical data would be required to assess any correlation of peak velocity flows with incidence of vascular injury, and any low-velocity flow regions with incidence of thrombosis.

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