[Pre-clinical validation of a turbine-based ventilator for invasive ventilation-The ACUTE-19 ventilator]. / Validación preclínica de un respirador de turbina para la ventilación invasiva: el respirador ACUTE-19.

Background: The severe acute respiratory syndrome-coronavirus 2 pandemic pressure on healthcare systems can exhaust ventilator resources, especially where resources are restricted. Our objective was a rapid preclinical evaluation of a newly developed turbine-based ventilator, named the ACUTE-19, for invasive ventilation. Methods: Validation consisted of (a) testing tidal volume delivery in 11 simulated models, with various resistances and compliances; (b) comparison with a commercial ventilator (VIVO-50) adapting the United Kingdom Medicines and Healthcare products Regulatory Agency-recommendations for rapidly manufactured ventilators; and (c) in vivo testing in a sheep before and after inducing acute respiratory distress syndrome by saline lavage. Results: Differences in tidal volume in the simulated models were marginally different (largest difference 33 ml [95% CI 31 to 36]; P < .001). Plateau pressure was not different (-0.3 cmH2O [95% CI -0.9 to 0.3]; P = .409), and positive end-expiratory pressure was marginally different (0.3 cmH2O [95% CI 0.2 to 0.3]; P < .001) between the ACUTE-19 and the commercial ventilator. Bland-Altman analyses showed good agreement (mean bias -0.29 [limits of agreement 0.82 to -1.42], and mean bias 0.56 [limits of agreement 1.94 to -0.81], at a plateau pressure of 15 and 30 cmH2O, respectively). The ACUTE-19 achieved optimal oxygenation and ventilation before and after acute respiratory distress syndrome induction. Conclusions: The ACUTE-19 performed accurately in simulated and animal models yielding a comparable performance with a VIVO-50 commercial device. The ACUTE-19 can provide the basis for the development of a future affordable commercial ventilator.

Validación preclínica de un respirador de turbina para la ventilación invasiva: el respirador ACUTE-19 Pre-clinical validation of a turbine-based ventilator for invasive ventilation–The ACUTE-19 ventilator

Graphical Antecedentes La pandemia producida por el síndrome respiratorio agudo severo por coronavirus 2 puede agotar los recursos sanitarios, especialmente de respiradores, en situaciones de escasez de recursos sanitarios. Nuestro objetivo fue realizar una evaluación preclínica rápida de un prototipo de respirador de turbina para la ventilación invasiva denominado ACUTE-19. Métodos La validación consistió en: a) evaluación de la administración de un volumen corriente en 11 modelos pulmonares simulados, con diversas resistencias y compliancias;b) comparación con un ventilador comercial (VIVO-50) adaptando las recomendaciones de la Agencia Reguladora de Medicamentos y Productos Sanitarios del Reino Unido para ventiladores de fabricación rápida, y c) realización de pruebas in vivo en una oveja antes y después de inducir el síndrome de distrés respiratorio agudo mediante lavado salino. Resultados Las diferencias de volumen corriente en los modelos simulados fueron mínimamente diferentes (la mayor diferencia fue de 33 ml [IC 95%: 31 a 36];p < 0,001). La presión de meseta no fue diferente (−0,3 cmH2O [IC 95%: −0,9 a 0,3];p = 0,409), y la presión positiva al final de la espiración fue levemente diferente (0,3 cmH2O [IC 95%: 0,2 a 0,3];p < 0,001) comparando el ACUTE-19 y el ventilador comercial. El análisis de Bland-Altman mostró una buena concordancia (sesgo medio −0,29 [límites de concordancia 0,82 a −1,42], y sesgo medio 0,56 [límites de concordancia 1,94 a −0,81], a una presión de meseta de 15 y 30 cmH2O, respectivamente). El ACUTE-19 consiguió una oxigenación y ventilación óptimas antes y después de la inducción del síndrome de distrés respiratorio agudo en el modelo animal. Conclusiones El ACUTE-19 se comportó con precisión en los modelos simulados y animales, con un rendimiento comparable al del dispositivo comercial VIVO-50. El ACUTE-19 puede servir de base para el desarrollo de un futuro ventilador comercial asequible.

Pre-clinical validation of a turbine-based ventilator for invasive ventilation-The ACUTE-19 ventilator.

BACKGROUND: The Severe Acute Respiratory Syndrome (SARS)-Coronavirus 2 (CoV-2) pandemic pressure on healthcare systems can exhaust ventilator resources, especially where resources are restricted. Our objective was a rapid preclinical evaluation of a newly developed turbine-based ventilator, named the ACUTE-19, for invasive ventilation. METHODS: Validation consisted of (a) testing tidal volume (V_T) delivery in 11 simulated models, with various resistances and compliances; (b) comparison with a commercial ventilator (VIVO-50) adapting the United Kingdom Medicines and Healthcare products Regulatory Agency-recommendations for rapidly manufactured ventilators; and (c) in vivo testing in a sheep before and after inducing acute respiratory distress syndrome (ARDS) by saline lavage. RESULTS: Differences in V_T in the simulated models were marginally different (largest difference 33ml [95%-confidence interval (CI) 31-36]; P<.001ml). Plateau pressure (P_plat) was not different (-0.3cmH₂O [95%-CI -0.9 to 0.3]; P=.409), and positive end-expiratory pressure (PEEP) was marginally different (0.3 cmH₂O [95%-CI 0.2 to 0.3]; P<.001) between the ACUTE-19 and the commercial ventilator. Bland-Altman analyses showed good agreement (mean bias, -0.29, [limits of agreement, 0.82 to -1.42], and mean bias 0.56 [limits of agreement, 1.94 to -0.81], at a P_plat of 15 and 30cmH₂O, respectively). The ACUTE-19 achieved optimal oxygenation and ventilation before and after ARDS induction. CONCLUSIONS: The ACUTE-19 performed accurately in simulated and animal models yielding a comparable performance with a VIVO-50 commercial device. The acute 19 can provide the basis for the development of a future affordable commercial ventilator.

Hyperoxemia in invasively ventilated COVID-19 patients-Insights from the PRoVENT-COVID study.

OBJECTIVE: We determined the prevalences of hyperoxemia and excessive oxygen use, and the epidemiology, ventilation characteristics and outcomes associated with hyperoxemia in invasively ventilated patients with coronavirus disease 2019 (COVID-19). METHODS: Post hoc analysis of a national, multicentre, observational study in 22 ICUs. Patients were classified in the first two days of invasive ventilation as 'hyperoxemic' or 'normoxemic'. The co-primary endpoints were prevalence of hyperoxemia (PaO2 > 90 mmHg) and prevalence of excessive oxygen use (FiO2 ≥ 60% while PaO2 > 90 mmHg or SpO2 > 92%). Secondary endpoints included ventilator settings and ventilation parameters, duration of ventilation, length of stay (LOS) in ICU and hospital, and mortality in ICU, hospital, and at day 28 and 90. We used propensity matching to control for observed confounding factors that may influence endpoints. RESULTS: Of 851 COVID-19 patients, 225 (26.4%) were classified as hyperoxemic. Excessive oxygen use occurred in 385 (45.2%) patients. Acute respiratory distress syndrome (ARDS) severity was lowest in hyperoxemic patients. Hyperoxemic patients were ventilated with higher positive end-expiratory pressure (PEEP), while rescue therapies for hypoxemia were applied more often in normoxemic patients. Neither in the unmatched nor in the matched analysis were there differences between hyperoxemic and normoxemic patients with regard to any of the clinical outcomes. CONCLUSION: In this cohort of invasively ventilated COVID-19 patients, hyperoxemia occurred often and so did excessive oxygen use. The main differences between hyperoxemic and normoxemic patients were ARDS severity and use of PEEP. Clinical outcomes were not different between hyperoxemic and normoxemic patients.

Invasive mechanical ventilation in patients with acute respiratory distress syndrome receiving extracorporeal support: a narrative review of strategies to mitigate lung injury.

Veno-venous extracorporeal membrane oxygenation is indicated in patients with acute respiratory distress syndrome and severely impaired gas exchange despite evidence-based lung protective ventilation, prone positioning and other parts of the standard algorithm for treating such patients. Extracorporeal support can facilitate ultra-lung-protective ventilation, meaning even lower volumes and pressures than standard lung-protective ventilation, by directly removing carbon dioxide in patients needing injurious ventilator settings to maintain sufficient gas exchange. Injurious ventilation results in ventilator-induced lung injury, which is one of the main determinants of mortality in acute respiratory distress syndrome. Marked reductions in the intensity of ventilation to the lowest tolerable levels under extracorporeal support may be achieved and could thereby potentially mitigate ventilator-induced lung injury and theoretically patient self-inflicted lung injury in spontaneously breathing patients with high respiratory drive. However, the benefits of this strategy may be counterbalanced by the use of continuous deep sedation and even neuromuscular blocking drugs, which may impair physical rehabilitation and impact long-term outcomes. There are currently a lack of large-scale prospective data to inform optimal invasive ventilation practices and how to best apply a holistic approach to patients receiving veno-venous extracorporeal membrane oxygenation, while minimising ventilator-induced and patient self-inflicted lung injury. We aimed to review the literature relating to invasive ventilation strategies in patients with acute respiratory distress syndrome receiving extracorporeal support and discuss personalised ventilation approaches and the potential role of adjunctive therapies in facilitating lung protection.

Awake prone positioning in nonintubated spontaneous breathing ICU patients with acute hypoxemic respiratory failure (PRONELIFE)-protocol for a randomized clinical trial.

BACKGROUND: It is uncertain whether awake prone positioning can prevent intubation for invasive ventilation in spontaneous breathing critically ill patients with acute hypoxemic respiratory failure. Awake prone positioning could benefit these patients for various reasons, including a reduction in direct harm to lung tissue, and prevention of tracheal intubation-related complications. DESIGN AND METHODS: The PRONELIFE study is an investigator-initiated, international, multicenter, randomized clinical trial in patients who may need invasive ventilation because of acute hypoxemic respiratory failure. Consecutive patients admitted to participating ICUs are randomly assigned to standard care with awake prone positioning, versus standard care without awake prone positioning. The primary endpoint is a composite of tracheal intubation and all-cause mortality in the first 14 days after enrolment. Secondary endpoints include time to tracheal intubation and effects of awake prone positioning on oxygenation parameters, dyspnea sensation, and complications. Other endpoints are the number of days free from ventilation and alive at 28 days, total duration of use of noninvasive respiratory support, total duration of invasive ventilation, length of stay in ICU and hospital, and mortality in ICU and hospital, and at 28, 60, and 90 days. We will also collect data regarding the tolerance of prone positioning. DISCUSSION: The PRONELIFE study is among the first randomized clinical trials investigating the effect of awake prone positioning on intubation rate in ICU patients with acute hypoxemic failure from any cause. The PRONELIFE study is sufficiently sized to determine the effect of awake prone positioning on intubation for invasive ventilation-patients are eligible in case of acute hypoxemic respiratory failure without restrictions regarding etiology. The PRONELIFE study is a pragmatic trial in which blinding is impossible-however, as around 35 ICUs worldwide will participate in this study, its findings will be highly generalizable. The findings of the PRONELIFE study have the potential to change clinical management of patients who may need invasive ventilation because of acute hypoxemic respiratory failure. TRIAL REGISTRATION: ISRCTN ISRCTN11536318 . Registered on 17 September 2021. The PRONELIFE study is registered at clinicaltrials.gov with reference number NCT04142736 (October, 2019).

Pragmatic Recommendations for the Prevention and Treatment of Acute Kidney Injury in Patients with COVID-19 in Low- and Middle-Income Countries

WATERLIT Abstract: Current recommendations for the management of patients with COVID-19 and acute kidney injury (AKI) are largely based on evidence from resource-rich settings, mostly located in high-income countries. It is often unpractical to apply these recommendations to resource-restricted settings. We report on a set of pragmatic recommendations for the prevention, diagnosis, and management of patients with COVID-19 and AKI in low- and middle-income countries (LMICs). For the prevention of AKI among patients with COVID-19 in LMICs, we recommend using isotonic crystalloid solutions for expansion of intravascular volume, avoiding nephrotoxic medications, and using a conservative fluid management strategy in patients with respiratory failure. For the diagnosis of AKI, we suggest that any patient with COVID-19 presenting with an elevated serum creatinine level without available historical values be considered as having AKI. If serum creatinine testing is not available, we suggest that patients with proteinuria should be considered to have possible AKI. We suggest expansion of the use of point-of-care serum creatinine and salivary urea nitrogen testing in community health settings, as funding and availability allow. For the management of patients with AKI and COVID-19 in LMICS, we recommend judicious use of intravenous fluid resuscitation. For patients requiring dialysis who do not have acute respiratory distress syndrome (ARDS), we suggest using peritoneal dialysis (PD) as first choice, where available and feasible. For patients requiring dialysis who do have ARDS, we suggest using hemodialysis, where available and feasible, to optimize fluid removal. We suggest using locally produced PD solutions when commercially produced solutions are unavailable or unaffordable

Practice of tracheostomy in patients with acute respiratory failure related to COVID-19 - Insights from the PRoVENT-COVID study.

OBJECTIVE: Invasively ventilated patients with acute respiratory failure related to coronavirus disease 2019 (COVID-19) potentially benefit from tracheostomy. The aim of this study was to determine the practice of tracheostomy during the first wave of the pandemic in 2020 in the Netherlands, to ascertain whether timing of tracheostomy had an association with outcome, and to identify factors that had an association with timing. METHODS: Secondary analysis of the 'PRactice of VENTilation in COVID-19' (PRoVENT-COVID) study, a multicenter observational study, conducted from March 1, 2020 through June 1, 2020 in 22 Dutch intensive care units (ICU) in the Netherlands. The primary endpoint was the proportion of patients receiving tracheostomy; secondary endpoints were timing of tracheostomy, duration of ventilation, length of stay in ICU and hospital, mortality, and factors associated with timing. RESULTS: Of 1023 patients, 189 patients (18.5%) received a tracheostomy at median 21 [17 to 28] days from start of ventilation. Timing was similar before and after online publication of an amendment to the Dutch national guidelines on tracheostomy focusing on COVID-19 patients (21 [17-28] vs. 21 [17-26] days). Tracheostomy performed ≤ 21 days was independently associated with shorter duration of ventilation (median 26 [21 to 32] vs. 40 [34 to 47] days) and higher mortality in ICU (22.1% vs. 10.2%), hospital (26.1% vs. 11.9%) and at day 90 (27.6% vs. 14.6%). There were no patient demographics or ventilation characteristics that had an association with timing of tracheostomy. CONCLUSIONS: Tracheostomy was performed late in COVID-19 patients during the first wave of the pandemic in the Netherlands and timing of tracheostomy possibly had an association with outcome. However, prospective studies are needed to further explore these associations. It remains unknown which factors influenced timing of tracheostomy in COVID-19 patients.

Pragmatic Recommendations for the Use of Diagnostic Testing and Prognostic Models in Hospitalized Patients with Severe COVID-19 in Low- and Middle-Income Countries

WATERLIT Abstract: Management of patients with severe or critical COVID-19 is mainly modeled after care of patients with severe pneumonia or acute respiratory distress syndrome from other causes. These models are based on evidence that primarily originates from investigations in high-income countries, but it may be impractical to apply these recommendations to resource-restricted settings in low- and middle-income countries (LMICs). We report on a set of pragmatic recommendations for microbiology and laboratory testing, imaging, and the use of diagnostic and prognostic models in patients with severe COVID-19 in LMICs. For diagnostic testing, where reverse transcription–PCR (RT-PCR) testing is available and affordable, we recommend using RT-PCR of the upper or lower respiratory specimens and suggest using lower respiratory samples for patients suspected of having COVID-19 but have negative RT-PCR results for upper respiratory tract samples. We recommend that a positive RT-PCR from any anatomical source be considered confirmatory for SARS-CoV-2 infection, but, because false-negative testing can occur, recommend that a negative RT-PCR does not definitively rule out active infection if the patient has high suspicion for COVID-19. We suggest against using serologic assays for the detection of active or past SARS-CoV-2 infection, until there is better evidence for its usefulness. Where available, we recommend the use of point-of-care antigen-detecting rapid diagnostic testing for SARS-CoV-2 infection as an alternative to RT-PCR, only if strict quality control measures are guaranteed. For laboratory testing, we recommend a baseline white blood cell differential platelet count and hemoglobin, creatinine, and liver function tests and suggest a baseline C-reactive protein, lactate dehydrogenase, troponin, prothrombin time (or other coagulation test), and D-dimer, where such testing capabilities are available. For imaging, where availability of standard thoracic imaging is limited, we suggest using lung ultrasound to identify patients with possible COVID-19, but recommend against its use to exclude COVID-19. We suggest using lung ultrasound in combination with clinical parameters to monitor progress of the disease and responses to therapy in COVID-19 patients. We currently suggest against using diagnostic and prognostic models as these models require extensive laboratory testing and imaging, which often are limited in LMICs

Pragmatic Recommendations for the Management of Anticoagulation and Venous Thrombotic Disease for Hospitalized Patients with COVID-19 in Low- and Middle-Income Countries

WATERLIT Abstract: New studies of COVID–19 are constantly updating best practices in clinical care. Often, it is impractical to apply recommendations based on high-income country investigations to resource limited settings in low- and middle-income countries (LMICs). We present a set of pragmatic recommendations for the management of anticoagulation and thrombotic disease for hospitalized patients with COVID-19 in LMICs. In the absence of contraindications, we recommend prophylactic anticoagulation with either low molecular weight heparin (LMWH) or unfractionated heparin (UFH) for all hospitalized COVID-19 patients in LMICs. If available, we recommend LMWH over UFH for venous thromboembolism (VTE) prophylaxis to minimize risk to healthcare workers. We recommend against the use of aspirin for VTE prophylaxis in hospitalized COVID-19 and non–COVID-19 patients in LMICs. Because of limited evidence, we suggest against the use of “enhanced” or “intermediate” prophylaxis in COVID-19 patients in LMICs. Based on current available evidence, we recommend against the initiation of empiric therapeutic anticoagulation without clinical suspicion for VTE. If contraindications exist to chemical prophylaxis, we recommend mechanical prophylaxis with intermittent pneumatic compression (IPC) devices or graduated compression stockings (GCS) for hospitalized COVID-19 patients in LMICs. In LMICs, we recommend initiating therapeutic anticoagulation for hospitalized COVID-19 patients, in accordance with local clinical practice guidelines, if there is high clinical suspicion for VTE, even in the absence of testing. If available, we recommend LMWH over UFH or Direct oral anticoagulants for treatment of VTE in LMICs to minimize risk to healthcare workers. In LMIC settings where continuous intravenous UFH or LMWH are unavailable or not feasible to use, we recommend fixed dose heparin, adjusted to body weight, in hospitalized COVID-19 patients with high clinical suspicion of VTE. We suggest D-dimer measurement, if available and affordable, at the time of admission for risk stratification, or when clinical suspicion for VTE is high. For hospitalized COVID-19 patients in LMICs, based on current available evidence, we make no recommendation on the use of serial D-dimer monitoring for the initiation of therapeutic anticoagulation. For hospitalized COVID-19 patients in LMICs receiving intravenous therapeutic UFH, we recommend serial monitoring of partial thromboplastin time or anti-factor Xa level, based on local laboratory capabilities. For hospitalized COVID-19 patients in LMICs receiving LMWH, we suggest against serial monitoring of anti-factor Xa level. We suggest serial monitoring of platelet counts in patients receiving therapeutic anticoagulation for VTE, to assess risk of bleeding or development of heparin induced thrombocytopenia

Pragmatic Recommendations for Tracheostomy, Discharge, and Rehabilitation Measures in Hospitalized Patients Recovering From Severe COVID-19 in Low- and Middle-Income Countries

WATERLIT Abstract: New studies of COVID-19 are constantly updating best practices in clinical care. However, research mainly originates in resource-rich settings in high-income countries. Often, it is impractical to apply recommendations based on these investigations to resource-constrained settings in low- and middle-income countries (LMICs). We report on a set of pragmatic recommendations for tracheostomy, discharge, and rehabilitation measures in hospitalized patients recovering from severe COVID-19 in LMICs. We recommend that tracheostomy be performed in a negative pressure room or negative pressure operating room, if possible, and otherwise in a single room with a closed door. We recommend using the technique that is most familiar to the institution and that can be conducted most safely. We recommend using fit-tested enhanced personal protection equipment, with the fewest people required, and incorporating strategies to minimize aerosolization of the virus. For recovering patients, we suggest following local, regional, or national hospital discharge guidelines. If these are lacking, we suggest deisolation and hospital discharge using symptom-based criteria, rather than with testing. We likewise suggest taking into consideration the capability of primary caregivers to provide the necessary care to meet the psychological, physical, and neurocognitive needs of the patient

Impaired ventilation is not independently associated with 28-day mortality in coronavirus disease 2019 (COVID19) acute respiratory distress syndrome (ARDS)

INTRODUCTION Surrogates for impaired ventilation such as estimated dead-space fractions and the ventilatory ratio are independently associated with an increased risk of mortality in the acute respiratory distress syndrome (ARDS) and small case series of COVID-19 related ARDS. METHODS This study aimed to quantify the dynamics and determine the prognostic value of surrogate markers of impaired ventilation in patients with COVID-19 related ARDS. The present study is a secondary analysis of the PRactice Of VENTilation in COVID-19 patients (PROVENT-COVID) in 22 intensive care unit hospitals in the Netherlands. Surrogates of impaired ventilation such as the estimated dead space fraction (by Harris-Benedict-VD/VT HB and direct method-VD/VT DIR), ventilatory ratio (VR), and end-tidal-to-arterial PCO2 ratio (PETCO2/PaCO2) were used. RESULTS 927 consecutive patients admitted with COVID-19 related ARDS were included in this study. Surrogates of impaired ventilation were significantly higher in non-survivors than survivors at baseline and during the following days of mechanical ventilation (p <0.001). As ARDS severity increased, mortality increased with successive tertiles for VD/VT HB and VD/VT DIR, and VR, and decreased with successive tertiles for PETCO2/PaCO2. Mortality over the first 28 days was higher in patients in the high group of dead space fraction by VD/VT HB (16.4% vs. 12.3%;p = 0.003), but similar in the groups considering the dead space fraction by VD/VT DIR (15.4% vs. 13.3%;p = 0.100), and VR (15.5% vs. 13.2%;p = 0.080) (Figure 2). After adjustment for a base risk model that included chronic comorbidities, ventilation and oxygenation parameters, none of the surrogates of impaired ventilation measured at the start of ventilation or the following days were significantly associated with 28-day mortality. CONCLUSION Surrogate markers for impaired ventilation are abnormal at the start of invasive ventilation in patients with COVID-19 related ARDS and worsen during consequent days. Ventilation impairment seems to be more extensive in non-survivors than in survivors, but they do not yield prognostic information when added to a baseline risk model. In the absence of bedside capnography, surrogates of impaired ventilation may serve as an important tool to assess the severity of COVID-19 related ARDS along with other variables such as oxygenation abnormalities and respiratory mechanics.

Update for Anaesthetists on Clinical Features of COVID-19 Patients and Relevant Management. LID - 1495

When preparing for the outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the coronavirus infection disease (COVID-19) questions arose regarding various aspects concerning the anaesthetist. When reviewing the literature it became obvious that keeping up-to-date with all relevant publications is almost impossible. We searched for and summarised clinically relevant topics that could help making clinical decisions. This is a subjective analysis of literature concerning specific topics raised in our daily practice (e.g., clinical features of COVID-19 patients;ventilation of the critically ill COVID-19 patient;diagnostic of infection with SARS-CoV-2;stability of the virus;Covid-19 in specific patient populations, e.g., paediatrics, immunosuppressed patients, patients with hypertension, diabetes mellitus, kidney or liver disease;co-medication with non-steroidal anti-inflammatory drugs (NSDOs);antiviral treatment) and we believe that these answers help colleagues in clinical decision-making. With ongoing treatment of severely ill COVID-19 patients other questions will come up. While respective guidelines on these topics will serve clinicians in clinical practice, regularly updating all guidelines concerning COVID-19 will be a necessary, although challenging task in the upcoming weeks and months. All recommendations during the current extremely rapid development of knowledge must be evaluated on a daily basis, as suggestions made today may be out-dated with the new evidence available tomorrow. FAU - Preckel, Benedikt