Long-term support of COVID-19 patients with veno-venous extracorporeal membrane oxygenation: Complications, predictors of mortality and long-term outcome

Objectives: Treatment of severe respiratory distress syndrome (ARDS) due to COVID-19 by veno-venous extracorporeal membrane oxygenation (VV-ECMO) had a mortality of up to 70% in Germany. Many patients with COVID-19 need VV-ECMO support longer than 28 days (long-term VV-ECMO). Evidence on mortality, complications during intensive care, functional status after discharge and mortality-predictors for patients supported with long-term VV-ECMO is lacking. Method(s): Retrospective study of 137 consecutive patients treated with VV-ECMO for ARDS due to COVID-19 at University Hospital Regensburg from March 2020 to March 2022. Result(s): 38% (n=52;87% male) of patients needed longterm VV-ECMO support. In these, SOFA score (median [IQR]) at ECMO initiation was 9 [8-11], age 58.2 [50.6- 62.5] years, PaO2/FiO2-ratio 67 [52-88] mmHg, pCO262 [52-74] mmHg, Murray-Score 3.3 [3.0-3.6] and PEEP 15 [13 - 16] cmH2O. Duration of long-term support was 45 [35-65] days. 26 (50%) patients were discharged from the ICU. Only one patient died after hospital discharge. At VVECMO initiation, baseline characteristics did not differ between deceased and survivors. Complications were frequent (acute kidney injury: 31/52, renal replacement therapy: 14/52, pulmonary embolism: 21/52, intracranial hemorrhage 8/52, major bleeding 34/52 and secondary sclerosing cholangitis: 5/52) and more frequent in the deceased. Karnofsky index (normal 100) after rehabilitation was 70 [57.5-82.5]. Twelve of the 18 patients discharged from rehabilitation had a satisfactory quality of life according to their own subjective assessment. Four patients required nursing support. Mortality-predictors within the first 30 days on VV-ECMO only observed in those who deceased later, were: Bilirubin >5mg/dl for > 7 days, pulmonary compliance <10ml/mbar for >14 days, and repeated serum concentrations of interleukin 8 >150ng/L. Conclusion(s): Long-term extracorporeal lung support in patients with COVID-19 resulted in 50 % survival and subsequently lead to a satisfactory quality of life and functionality in the majority of patients. It should preferably be performed in experienced centers because of a high incidence of complications. Several findings during the early course were associated with late mortality but need validation in large prospective studies.

Determinants of death in patients with COVID-19 pneumonia treated with venovenous extracorporeal membrane oxygenation support

Objectives: Death from SARS-CoV-2 pneumonia resulted from progressive respiratory failure in most patients. Whenever accessible, venovenous extracorporeal membrane oxygenation (VVECMO) was implemented to rescue patients with refractory hypoxemia. Reported mortality in this population reached values from 20 to 50 percent, but the direct causes of death were not so widely acknowledged. The aim of our study was to characterize mortality in patients treated with VVECMO support. Method(s): Retrospective review of a prospectively collected database in an ECMO referral centre. All patients with diagnosis of SARS-CoV-2 infection treated with VVECMO support were included. Survivors and nonsurvivors were compared using t-student and chi2 methods. A Cox regression analysis was performed to identify predictors of mortality at admission. Result(s): Ninety-three patients were included (29% female). Median age was 54+/-12 years, mean SOFA was 5.7+/-2.9 and SAPS II was 35.6+/-13.6. Hospital mortality was 24.7%. Main causes of death were septic shock in 39.1% (9 patients), irreversible lung fibrosis 30.4% (7 patients) and catastrophic hemorrhage in 4.3% (4 patients). End-of-life care measures (withdrawal or withholding) were adopted in 65.2% of non-survivals. Patients who died were older (55 vs 48 years, p<0.05), had longer disease course (19 vs 15.3 days, p<0.05), longer invasive mechanical ventilation course before cannulation (8.5 vs 5 days, p<0.05), lower static lung compliance (25.5 vs 31.8 mL/cmH2O, p<0.05) and were ventilated with lower PEEP (8 vs 10 cmH2O, p<0.05) on cannulation. On a Cox-regression model, only prone ventilation before cannulation (HR 9,7;CI 95% 1,4- 68,6;p<0.05) and SAPS II (HR 1.04;CI 95% 1,001- 1,083;p<0.05) predicted mortality. Conclusion(s): Mortality in patients with severe SARSCoV-2 pneumonia treated with VVECMO was exceedingly low in our study, when compared with other series. Only one-third died from progressive lung disease, which suggests that protocol improvement can further reduce mortality.

Dysphagia rehabilitation in post-COVID patients: Review of the literature

COVID-19 causes acute respiratory failure syndrome (SIRA), leading patients to require intubation in the intensive care unit (ICU). A common complication of this ventilatory support is dysphagia, which has a prevalence of up to 30%.This work aims to describe rehabilitation methods in patients with coronavirus infection based on levels of evidence according to the GRADE System, so a systematic review of the literature was carried out. The selected articles were divided into the following subtopics: diagnosis of dysphagia and rehabilitation in COVID patients. The gold standard for the diagnosis of dysphagia is the videofluoroscopic swallowing study (VFS). Fiberoptic Evaluation of Swallowing Assessment (FEES) has high sensitivity and specificity, although they have the disjunction of an aerosol-generating procedure (AGP);however, in a pandemic situation, the study of choice in the literature is VF. Once the diagnosis is made, it is necessary to initiate rehabilitation as soon as possible, even from hospitalization in patients who have hemodynamic stability to prevent long-term effects and promote normal swallowing even before discharge. In patients with COVID-19 infection dysphagia, the risk-benefit of assessment tools and therapy used for diagnosis should be decided to help to maintain social distancing. It becomes imperative to carry out clinical studies with high levels of evidence that allow us to generate Clinical Practice Guides for the benefit of our patients.Copyright © 2021 Sociedad Medica del Hospital General de Mexico. Published by Permanyer.

Clinical characteristics and risk factors of patients with COVID-19 developing barotrauma

Background: At our hospital, people with COVID-19 (coronavirus disease 2019) had a high rate of pulmonary barotrauma. Therefore, the current study looked at barotrauma in COVID-19 patients getting invasive and non-invasive positive pressure ventilation to assess its prevalence, clinical results, and features. Methodology: Our retrospective cohort study comprised of adult COVID-19 pneumonia patients who visited our tertiary care hospital between April 2020 and September 2021 and developed barotrauma. Result(s): Sixty-eight patients were included in this study. Subcutaneous emphysema was the most frequent type of barotrauma, reported at 67.6%;pneumomediastinum, reported at 61.8%;pneumothorax, reported at 47.1%. The most frequent device associated with barotrauma was CPAP (51.5%). Among the 68 patients, 27.9% were discharged without supplemental oxygen, while 4.4% were discharged on oxygen. 76.5% of the patients expired because of COVID pneumonia and its complications. In addition, 38.2% of the patients required invasive mechanical breathing, and 77.9% of the patients were admitted to the ICU. Conclusion(s): Barotrauma in COVID-19 can pose a serious risk factor leading to mortality. Also, using CPAP was linked to a higher risk of barotrauma.Copyright © 2021 Muslim OT et al.

ECMO for the immunocompromised pediatric patient: Our experience

Objectives: To present a series of immunosuppressed patients (oncohematological disease, congenital immunosuppression, hematopoietic stem cell (HSCT), and solid organ transplant) assisted on ECMO. Method(s): Descriptive, retrospective study (2011-2020) of a cohort of 9 immunosuppressed patients, supported on ECMO. Medical records were reviewed and demographic, clinical, and analytical variables were collected. Result(s): In our series of 9 patients, 5 were male, the median age was 8 years [RIC 3-11 years]. Considering the underlying disease, 6 were oncologic, 1 liver transplant and 2 with congenital immunodeficiency after HSCT. 4 were under active chemotherapy (median 6 days after the last cycle [RIC 5-188]). 6 were admitted due to acute respiratory failure, 3 due to hemodynamic instability (3/9), (one septic shock). The median PEEP was 12 [RIC 9-15] and FiO2 100% (81-100%). 78% (6) required vasoactive drugs (median inotropic score 35 [RIC 0-75]. 40%. 5 had severe neutropenia and/or plateletopenia in the 24 hours prior to ECMO, and alterations in acid-base balance (median pH 7. 1 [RIC 6.9-7.15]. 5 were on multiorgan failure. TPrimary ECMO transport was performed in 4 patients (44%). Cannulation was peripheral in 80% (57% cervical, 43% femoral) and central in 20%;70% VA-ECMO. Median time of assistance was 15 days [RIC 3.5-31.5] in cardiac ECMO (4), and 29 days [RIC 13.5-42] and in pulmonary ECMO (n=5). The median total time of admission was 45 days [RIC 27-59]. 9 had an infection, 2 COVID after HSCT, and 8 bleeding complications, but only one required surgical revision. Renal replacement therapy was used in 5 (median 9 days [RIC 5-34.5]). Other therapies used were polymyxin hemadsorption(2), intratracheal surfactant(2), plasma exchange(1), infusion of mesenchymal cells(1) and specific memory T lymphocytes(2). 4 patients died, 5 survived decannulation, 2 died later, with an overall survival rate to hospital discharge of 33% (3/9). Conclusion(s): Despite having a worse prognosis, ECMO can increase survival in immunosuppressed patients, in situations that are challenging and require a multidisciplinary approach.

Relationship between positive end-expiratory pressure levels, central venous pressure, systemic inflammation and acute renal failure in critically ill ventilated COVID-19 patients: a monocenter retrospective study in France.

BACKGROUND: The role of positive pressure ventilation, central venous pressure (CVP) and inflammation on the occurrence of acute kidney injury (AKI) have been poorly described in mechanically ventilated patient secondary to coronavirus disease 2019 (COVID-19). METHODS: This was a monocenter retrospective cohort study of consecutive ventilated COVID-19 patients admitted in a French surgical intensive care unit between March 2020 and July 2020. Worsening renal function (WRF) was defined as development of a new AKI or a persistent AKI during the 5 days after mechanical ventilation initiation. We studied the association between WRF and ventilatory parameters including positive end-expiratory pressure (PEEP), CVP, and leukocytes count. RESULTS: Fifty-seven patients were included, 12 (21%) presented WRF. Daily PEEP, 5 days mean PEEP and daily CVP values were not associated with occurrence of WRF. 5 days mean CVP was higher in the WRF group compared to patients without WRF (median [IQR], 12 mm Hg [11-13] vs. 10 mm Hg [9-12]; P=0.03). Multivariate models with adjustment on leukocytes and Simplified Acute Physiology Score (SAPS) II confirmed the association between CVP value and risk of WRF (odd ratio, 1.97; 95% confidence interval, 1.12-4.33). Leukocytes count was also associated with occurrence of WRF in the WRF group (14 G/L [11-18]) and the no-WRF group (9 G/L [8-11]) (P=0.002). CONCLUSIONS: In mechanically ventilated COVID-19 patients, PEEP levels did not appear to influence occurrence of WRF. High CVP levels and leukocytes count are associated with risk of WRF.

Invasive Mechanical Ventilation in COVID-19

Patients with severe COVID-19 pneumonia present with severe hypoxemic respiratory failure, typically meet the clinical criteria for acute respiratory distress syndrome (ARDS) and often require invasive mechanical ventilation. While peculiar pathophysiological aspects deserve discussion to better tailor the mechanical ventilation settings in these patients, most recommendations on the ventilatory management of these patients are derived from studies in patients with ARDS from causes other than COVID-19. Protective ventilation is recommended in most COVID-19 patients, tidal volume should be kept around 6 mL per kg of predicted body weight, positive end-expiratory pressure (PEEP) should be titrated individually considering that in many patients with COVID-19 improvement of oxygenation at higher PEEP is often accompanied by worsening of respiratory system compliance. Therefore, attention should be paid in limiting plateau and driving pressures to avoid excessive strain potentially resulting in ventilator-induced lung injury. Prone positioning has been used extensively in COVID-19 patients, but its impact on mortality is uncertain. Inhaled nitric oxide, extracorporeal CO2 removal (ECCO2R), and extracorporeal membrane oxygenation (ECMO) should be considered in selected patients as rescue measures. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.

Case Report of a Transfusion-Associated Circulatory Overload Leading to Cardiac Arrest in a COVID-19 Positive Patient

Although case reports have been made regarding adverse transfusion reactions, few have been made regarding blood transfusions leading to cardiac arrest. Today, we present a case of a COVID-19 positive Bahraini male, triple vaccinated, transfused with packed red blood cell (pRBC) after finding out he has low haemoglobin levels (64 g/dl) after routine laboratory investigations. During the blood transfusion, he developed hypertension, tachycardia and tachypnoea. The patient went into cardiac arrest within a few minutes of this presentation. Return of spontaneous circulation was achieved, and the patient was managed as transfusion-associated circulatory overload (TACO) with a good overall outcome.Copyright © 2023, Bahrain Medical Bulletin. All rights reserved.

Lung inhomogeneities in COVID-19 related acute respiratory distress syndrome

Introduction: In acute respiratory distress syndrome (ARDS) inhomogeneities in lung aeration can act as local multipliers of pressure during inspiration (stress risers), increasing the risk of lung damage even in presence of airway pressures considered safe [1]. In this study we aimed to describe lung inhomogeneities in COVID-19 related ARDS (C-ARDS) and to relate these to disease severity and lung morphology. Method(s): We enrolled patients with C-ARDS within 3 days from mechanical ventilation start, deeply sedated and paralyzed. Lung CT scan was obtained at PEEP of 5 cmH2O to measure lung weight compartments (non-, poorly-, well- and over-aerated). Lung inhomogeneities were computed as the gas/tissue ratio of each voxel compared to the neighboring voxels. We considered values > 1.61 as pathologic lung inhomogeneities, as previously described [1]. The fraction of total lung volume with pathologic inhomogeneities (extent) and the average severity of inhomogeneities contained in that fraction (intensity) was calculated. Respiratory system compliance and blood gas analysis were obtained at the same PEEP level of the CT scan. Some results have been presented in another publication [2]. Result(s): Forty patients were studied in the supine position 1 (0-1) days after ICU admission. The extent of pathologic lung inhomogeneities represented 18 +/- 4% of total lung volume. The intensity of pathologic lung inhomogeneities was on average 2.53 +/- 0.12. Extent was positively correlated with the amount of poorly aerated lung weight ( r2 = 0.51, p < 0.001) (Fig. 1) and negatively correlated with the amount of non-aerated lung weight ( r2 = 0.22, p = 0.002). No correlation was found between extent and intensity and PaO2/ FiO2, dead space fraction or respiratory system compliance. Conclusion(s): In C-ARDS lung inhomogeneities represent roughly 20% of total lung volume. In these regions local stress is increased with risk of secondary lung damage.

Ventilator management and risk of air leak syndrome for patients with COVID-19 pneumonia

Introduction: Coronavirus disease 2019 (COVID-19) pneumonia is reportedly associated with air leak syndrome (ALS), including mediastinal emphysema and pneumothorax, and has a high mortality rate. In this study, we compared values obtained every minute from the ventilator to clarify the relationship between ventilatory management and the risk of developing ALS. Method(s): This was a single-center, retrospective, observational study for a 21-months period. Patient background, ventilator data, and outcomes were collected from adult patients with COVID-19 pneumonia on ventilator-assisted respiratory management. The primary outcome was the development of ALS within 30 days of starting ventilator management. Result(s): Of the 105 patients, 14 (13%) developed ALS. The mean positive-end expiratory pressure (PEEP) difference was 0.33 cmH2O (95% confidence interval (CI) 0.31-0.33), and it was higher in the ALS than in the non-ALS group (9.18 +/- 2.20 versus 8.85 +/- 2.63, respectively). For peak pressure, the mean difference was -0.18 cmH2O (95% CI -0.20 to -0.15), (20.70 +/- 5.30 vs. 20.87 +/- 5.65) and the mean pressure difference of -0.05 cmH2O (95% CI -0.04 to -0.07) (12.80 +/- 3.13 vs. 12.85 +/- 3.55, respectively) was also higher in the non-ALS group. The difference in the single ventilation volume per ideal body weight was 0.65 ml/kg (95% CI 0.63-0.66) (7.83 +/- 3.16 vs. 7.18 +/- 2.96, respectively), and the difference in dynamic lung compliance was 8.57 mL/cmH2O (95% CI 8.43-8.70) (50.32 +/- 31.68 vs. 49.68 +/- 15.16, respectively), and both were higher in the ALS group. The percentage of times that the ventilation volume per body weight exceeded 8 was higher in the ALS group (53.7% vs. 38.6%, p < 0.001). Conclusion(s): There was no association between higher ventilator pressures and the development of ALS. The ALS group had higher dynamic lung compliance and higher tidal volumes, which may indicate a pulmonary contribution to ALS, and ventilatory management that limits tidal volume may prevent the development of ALS.

Prolonged prone position in COVID-19-associated ARDS: a prospective study

Introduction: Ventilation in prone-position (PP) improves survival in moderate-to-severe ARDS. However, optimal duration of the intervention to gain maximum benefit is unknown. We sought to examine the efficacy and safety of a prolonged PP protocol in COVID-19-associated ARDS. Method(s): This was a prospective observational study. We included consecutive intubated and mechanically ventilated patients with ARDS and positive PCR for SARS-CoV-2 who underwent at least one session of PP from March 2021 to August 2021. PP was undertaken if P/F < 150 with FiO2 > 0.6 and PEEP > 10cmH2O. Oxygenation parameters and respiratory mechanics were recorded before PP, at the end of PP session and 4 h after supine repositioning. Patients with PP longer than 24 h (prolonged group) were compared to patients who were proned for less than 24 h (control group). The duration of PP was at the discretion of the treating intensivist. Result(s): We recorded 56 patients (62.7% male). Five patients were excluded because PP was terminated in less than 4 h. Mean age of the 51 studied patients was 61.4 years. Patients in the prolonged group had significantly higher BMI than controls. Baseline oxygenation and respiratory mechanics were similar between groups. PP duration was 39.8 versus 20.5 h (p < 0.001). Increase of P/F was higher in the prolonged PP group during proning (103.8 +/- 70.8 vs 66 +/- 53.9, p < 0.05) and after supination (76.3 +/- 64.6 vs 48.6 +/- 34.9, p = 0.058). No change in respiratory mechanics was observed in either group. 28-day survival was 75% in the prolonged PP group and 69.5% in the control group (p = 0.665). Duration of mechanical ventilation, number of PP cycles and rate of complications were similar between groups. Conclusion(s): In patients with ARDS due to COVID-19 prolonged PP resulted in better oxygenation, but had no impact on outcome. However, it is both feasible and safe and can be an alternative in conditions of increased work load as was the case during the recent pandemic.

Latent class analysis of imaging and clinical respiratory parameters from patients with COVID-19-related ARDS identifies recruitment subphenotypes

Introduction: Patients with COVID-19-related acute respiratory distress syndrome (ARDS) require respiratory support with invasive mechanical ventilation and show varying responses to recruitment manoeuvres. In patients with ARDS not related to COVID-19, two pulmonary subphenotypes that differed in recruitability were identified using latent class analysis (LCA) of imaging and clinical respiratory parameters [1]. We aimed to validate these phenotypes and evaluate if similar subphenotypes are present in patients with COVID-19-related ARDS. Method(s): This is the retrospective analysis of mechanically ventilated patients with COVID-19-related ARDS who underwent CT scans at positive end-expiratory pressure of 10 cmH2O and after a recruitment manoeuvre at 20 cmH2O. LCA was applied to quantitative CT-derived parameters, clinical respiratory parameters, blood gas analysis and routine laboratory values before recruitment to identify subphenotypes. Result(s): 99 patients were included. Using 12 variables, a two-class LCA model was identified as best fitting. Subphenotype 2 (recruitable) was characterized by a lower PaO2/ FiO2, lower normally aerated lung volume and lower compliance as opposed to a higher nonaerated lung mass and higher mechanical power when compared to subphenotype 1 (non-recruitable) (Fig. 1). Patients with subphenotype 2 had more decrease in non-aerated lung mass in response to a standardized recruitment manoeuvre (p = 0.024) and were mechanically ventilated longer until successful extubation (adjusted SHR 0.46, 95% CI 0.23-0.91, p = 0.026), while no difference in survival was found (p = 0.814). Conclusion(s): A recruitable and non-recruitable subphenotype were identified in patients with COVID-19-related ARDS. The subphenotypes are similar to non-COVID-19-related ARDS and are promising for identification of recruitable patients in future practice as they can be classified with only few clinically available parameters before the recruitment manoeuvre.

A nationwide cohort study of pregnant and postpartum patients with severe COVID-19 pneumonitis in ICU in Israel

Introduction: This study included pregnant patients with severe COVID to test the hypothesis that the impact of delivery on maternal outcome depends upon illness severity at the time of delivery;we hypothesized that patients not yet requiring IPPV would improve following delivery (due to improvement in respiratory mechanics), while patients already on IPPV, or close to requiring ventilation, would deteriorate (due to maternal cardiovascular intolerance to autotransfusion). Method(s): This multicenter, prospective/retrospective cohort study evaluated Israeli ICU admissions of pregnant women with COVID-19 pneumonitis from 1-Feb-2020 to 31-Jan-2022. We assessed maternal, neonatal outcomes and longitudinal maternal clinical data. The primary outcome was maternal outcome (no-IPPV, IPPV, ECMO, death). The primary longitudinal outcome was SOFA score, the secondary longitudinal outcome was the novel PORCH score (PEEP, Oxygenation, Respiratory-support, Chest-X-ray, Haemodynamic-support). Patients were classified into: no-delivery, postpartum admission, deliverycritical and delivery-not-critical groups. Result(s): 84 patients in 13 ICUs were analysed;there were 34 nodelivery, 4 postpartum, 32 delivery-critical, 14 delivery-not-critical patients. Delivery-critical and postpartum had worse outcomes with, 26/32(81%) and 4/4(100%) requiring IPPV;12/32(38%) and 3/4(75%) requiring ECMO;1/32(3%) and 2/4(50%) dying. Deliverynot- critical and no-delivery had far better outcomes with, respectively, 6/34(18%) and 2/14(14%) requiring mechanical ventilation;no patients required ECMO or died. SpO2, S/F ratio, P/F ratio in Deliverycritical deteriorated on the day of delivery, continued to deteriorate, and took longer to recover;delivery-not-critical improved rapidly following delivery. The day of delivery was a highly significant covariate for PORCH (p < 0.0001), not SOFA (p = 0.09). Conclusion(s): Interventional delivery should be considered for maternal indications before patients deteriorate and require IPPV.

Lung ultrasound scoring system vs ROX index as a predictor for progression to the invasive mechanical ventilation in COVID-19 patients

Background: During the outbreak of the highly contagious Coronavirus disease 19 (COVID19), rapid and simple prognostic tools were needed to support clinical decisions and predict the need of invasive mechanical ventilation. the ROX index, and the lung ultrasound score (LUSS) were proposed to objectively predict patient prognosis in addition to the subjective clinical assessment Aim: This study aimed to compare lung ultrasound score with ROX index in predicting the need of invasive ventilation in COVID-19 patients requiring advanced oxygen therapy. Patients and Methods: We studied 50 patients with severe COVID-19 pneumonia in the intensive care unit in the isolated area at Kasr Al-Ainy hospital. Complete Medical history, physical examination and laboratory investigations were obtained on admission. All patients underwent bedside lung ultrasonography scan and LUSS was calculated at the 2nd and the 12th hours, also ROX index was calculated at the 2nd, 6th and 12th hours from initiating the advanced oxygen therapy. Result(s): From a total of fifty patients with COVID-19, 56.0% were males, with mean age of 65.98 + 11.68 years, and mortality rate was 68%. The optimal cut off value of the ROX index at (2, 6, 12 hour) is (2.495, 2.675, 3.06) respectively, (p <0.001) with sensitivity 90.9% and specificity 76.5% at the 12 hour. Also the optimal cut off point of LUSS is 25.50 (p <0.001) with sensitivity 93.9% and specificity 88.2% for prediction of the invasive mechanical ventilation. Conclusion and recommendations: The study concluded that LUSS is more sensitive in predicting the need of invasive mechanical ventilation than ROX index.Copyright © 2023, Codon Publications. All rights reserved.

Tidal volume measurement during non-invasive respiratory support by helmet continuous-flow CPAP is feasible and accurate in a bench model

Introduction: We investigated a novel technique designed to measure tidal volume during non-invasive helmet continuous-flow CPAP, a device for non-invasive respiratory support largely used during the recent COVID-19 pandemic to treat acutely ill hypoxic respiratory failure patients. Method(s): An active lung simulator coupled with a helmet CPAP was used to compare measured and Reference tidal volumes at PEEP 5, 10 and 15 cmH2O and different levels of distress (pMusc 10, 15 20 and 25 cmH2O;respiratory rate 15, 20, 25 breaths per minutes). Tidal volume measurement was based on helmet outflow-trace analysis. Helmet inflow was increased from 60 to 75 and 90 L/min to match patients' inspiratory flow;an additional subset of tests was conducted in condition of purposely insufficient inflow (i.e.: high respiratory distress and 60 L/min inflow). Result(s): Explored tidal volumes ranged from 250 to 910 mL. The Bland-Altman analysis showed a bias of -3.2 +/- 29.3 mL for measured tidal volumes as compared to Reference, corresponding to an average relative error of -1 +/- 4.4% (see Fig. 1). At univariate analyses, tidal volume underestimation correlated with respiratory rate (rho = .411, p = .004) but not with peak inspiratory flow, distress, or PEEP. When the helmet inflow was purposely maintained insufficient as compared to the simulated inspiratory flow, the Bland-Altman analysis showed a significant tidal volume underestimation (bias -93.3 +/- 83.9 mL), corresponding to an error of -14.8 +/- 6.3%. Conclusion(s): We showed that tidal volume measurement is feasible and accurate in a model of bench continuous-flow helmet CPAP therapy by the analysis of the outflow signal, provided that helmet inflow is maintained adequate to match patient's inspiratory efforts. Insufficient inflow resulted in tidal volume underestimation.

Epidemiological profile and risk factors associated with death in patients receiving invasive mechanical ventilation in an adult intensive care unit from Brazil: a retrospective study.

Introduction: Understanding the epidemiological profile and risk factors associated with invasive mechanical ventilation (IMV) is essential to manage the patients better and to improve health services. Therefore, our objective was to describe the epidemiological profile of adult patients in intensive care that required IMV in-hospital treatment. Also, to evaluate the risks associated with death and the influence of positive end-expiratory pressure (PEEP) and arterial oxygen pressure (PaO2) at admission in the clinical outcome. Methods: We conducted an epidemiological study analyzing medical records of inpatients who received IMV from January 2016 to December 2019 prior to the Coronavirus Disease (COVID)-19 pandemic in Brazil. We considered the following characteristics in the statistical analysis: demographic data, diagnostic hypothesis, hospitalization data, and PEEP and PaO2 during IMV. We associated the patients' features with the risk of death using a multivariate binary logistic regression analysis. We adopted an alpha error of 0.05. Results: We analyzed 1,443 medical records; out of those, 570 (39.5%) recorded the patients' deaths. The binary logistic regression was significant in predicting the patients' risk of death [X2(9) = 288.335; p < 0.001]. Among predictors, the most significant in relation to death risk were: age [elderly ≥65 years old; OR = 2.226 (95%CI = 1.728-2.867)]; male sex (OR = 0.754; 95%CI = 0.593-0.959); sepsis diagnosis (OR = 1.961; 95%CI = 1.481-2.595); need for elective surgery (OR = 0.469; 95%CI = 0.362-0.608); the presence of cerebrovascular accident (OR = 2.304; 95%CI = 1.502-3.534); time of hospital care (OR = 0.946; 95%CI = 0.935-0.956); hypoxemia at admission (OR = 1.635; 95%CI = 1.024-2.611), and PEEP >8 cmH2O at admission (OR = 2.153; 95%CI = 1.426-3.250). Conclusion: The death rate of the studied intensive care unit was equivalent to that of other similar units. Regarding risk predictors, several demographic and clinical characteristics were associated with enhanced mortality in intensive care unit patients under mechanical ventilation, such as diabetes mellitus, systemic arterial hypertension, and older age. The PEEP >8 cmH2O at admission was also associated with increased mortality since this value is a marker of initially severe hypoxia.

Effect of EIT-guided PEEP titration on prognosis of patients with moderate to severe ARDS: study protocol for a multicenter randomized controlled trial.

BACKGROUND: Acute respiratory syndrome distress (ARDS) is a clinical common syndrome with high mortality. Electrical impedance tomography (EIT)-guided positive end-expiratory pressure (PEEP) titration can achieve the compromise between lung overdistension and collapse which may minimize ventilator-induced lung injury in these patients. However, the effect of EIT-guided PEEP titration on the clinical outcomes remains unknown. The objective of this trial is to investigate the effects of EIT-guided PEEP titration on the clinical outcomes for moderate or severe ARDS, compared to the low fraction of inspired oxygen (FiO2)-PEEP table. METHODS: This is a prospective, multicenter, single-blind, parallel-group, adaptive designed, randomized controlled trial (RCT) with intention-to-treat analysis. Adult patients with moderate to severe ARDS less than 72 h after diagnosis will be included in this study. Participants in the intervention group will receive PEEP titrated by EIT with a stepwise decrease PEEP trial, whereas participants in the control group will select PEEP based on the low FiO2-PEEP table. Other ventilator parameters will be set according to the ARDSNet strategy. Participants will be followed up until 28 days after enrollment. Three hundred seventy-six participants will be recruited based on a 15% decrease of 28-day mortality in the intervention group, with an interim analysis for sample size re-estimation and futility assessment being undertaken once 188 participants have been recruited. The primary outcome is 28-day mortality. The secondary outcomes include ventilator-free days and shock-free days at day 28, length of ICU and hospital stay, the rate of successful weaning, proportion requiring rescue therapies, compilations, respiratory variables, and Sequential Organ Failure Assessment (SOFA). DISCUSSION: As a heterogeneous syndrome, ARDS has different responses to treatment and further results in different clinical outcomes. PEEP selection will depend on the properties of patients and can be individually achieved by EIT. This study will be the largest randomized trial to investigate thoroughly the effect of individual PEEP titrated by EIT in moderate to severe ARDS patients to date. TRIAL REGISTRATION: ClinicalTrial.gov NCT05207202. First published on January 26, 2022.

Long-Term Sequelae of severe COVID-19: Outpatient assessment of radiological and pulmonary function tests

Objective: Identify lung sequelae of COVID-19 through radiological and pulmonary function assessment. Design(s): Prospective, longitudinal, cohort study from March 2020 to March 2021. Setting(s): Intensive Care Units (ICU) in a tertiary hospital in Portugal. Patient(s): 254 patients with COVID-19 admitted to ICU due to respiratory illness. Intervention(s): A chest computed tomography (CT) scan and pulmonary function tests (PFT) were performed at 3 to 6 months. Main variables of interest: CT-scan;PFT;decreased diffusion capacity of carbon monoxide (DLCO). Result(s): All CT scans revealed improvement in the follow-up, with 72% of patients still showing abnormalities, 58% with ground glass opacities and 62% with evidence of fibrosis. PFT had abnormalities in 94 patients (46%): thirteen patients (7%) had an obstructive pattern, 35 (18%) had a restrictive pattern, and 58 (30%) had decreased DLCO. There was a statistically significant association between abnormalities in the follow-up CT scan and older age, more extended hospital and ICU stay, higher SAPS II and APACHE scores and invasive ventilation. Mechanical ventilation, especially with no lung protective parameters, was associated with abnormalities in PFT. Multivariate regression showed more abnormalities in lung function with more extended ICU hospitalization, chronic obstructive pulmonary disease (COPD), chronic kidney disease, invasive mechanical ventilation, and ventilation with higher plateau pressure, and more abnormalities in CT-scan with older age, more extended ICU stay, organ solid transplants and ventilation with higher positive end-expiratory pressure (PEEP). Conclusion(s): Most patients with severe COVID-19 still exhibit abnormalities in CT scans or lung function tests three to six months after discharge.Copyright © 2023

Ventilatory support in Covid-19 pneumonia.

The Covid-19 pandemic led to a major influx of patients suffering from acute hypoxemic respiratory failure, which conducted intensivists to adapt ICU structures and question respiratory support strategies. Available data suggest that pathophysiology of Covid-19 associated - acute respiratory distress syndrome (ARDS) is substantially similar to the pathophysiology of ARDS unrelated to Covid-19. Specific vascular injuries may however be more frequent during Covid-19 and some patients may present a major alteration in hypoxic pulmonary vasoconstriction. To date, ventilatory support strategies of patients with Covid-19 should be in line with guidelines for ARDS unrelated to Covid-19, including in particular a cautious evaluation of positive end-expiratory pressure effects.Copyright © SRLF 2021.