Interpretable machine learning-based predictive modeling of patient outcomes following cardiac surgery.

BACKGROUND: The clinical applicability of machine learning predictions of patient outcomes following cardiac surgery remains unclear. We applied machine learning to predict patient outcomes associated with high morbidity and mortality after cardiac surgery and identified the importance of variables to the derived model's performance. METHODS: We applied machine learning to the Society of Thoracic Surgeons Adult Cardiac Surgery Database to predict postoperative hemorrhage requiring reoperation, venous thromboembolism (VTE), and stroke. We used permutation feature importance to identify variables important to model performance and a misclassification analysis to study the limitations of the model. RESULTS: The study dataset included 662,772 subjects who underwent cardiac surgery between 2015 and 2017 and 240 variables. Hemorrhage requiring reoperation, VTE, and stroke occurred in 2.9%, 1.2%, and 2.0% of subjects, respectively. The model performed remarkably well at predicting all 3 complications (area under the receiver operating characteristic curve, 0.92-0.97). Preoperative and intraoperative variables were not important to model performance; instead, performance for the prediction of all 3 outcomes was driven primarily by several postoperative variables, including known risk factors for the complications, such as mechanical ventilation and new onset of postoperative arrhythmias. Many of the postoperative variables important to model performance also increased the risk of subject misclassification, indicating internal validity. CONCLUSIONS: A machine learning model accurately and reliably predicts patient outcomes following cardiac surgery. Postoperative, as opposed to preoperative or intraoperative variables, are important to model performance. Interventions targeting this period, including minimizing the duration of mechanical ventilation and early treatment of new-onset postoperative arrhythmias, may help lower the risk of these complications.

How I manage differential gas exchange in peripheral venoarterial extracorporeal membrane oxygenation.

Dual circulation is a common but underrecognized physiological occurrence associated with peripheral venoarterial extracorporeal membrane oxygenation (ECMO). Competitive flow will develop between blood ejected from the heart and blood travelling retrograde within the aorta from the ECMO reinfusion cannula. The intersection of these two competitive flows is referred to as the "mixing point". The location of this mixing point, which depends upon the relative strengths of the native and extracorporeal pumps, will determine which regions of the body are perfused with blood ejected from the left ventricle and which regions are perfused by reinfused blood from the ECMO circuit, effectively establishing dual circulations. Because gas exchange within these circulations is dictated by the native lungs and membrane lung, respectively, oxygenation and carbon dioxide removal may differ between regions-depending on how well gas exchange is preserved within each circulation-potentially leading to differential oxygenation or differential carbon dioxide, each of which may have important clinical implications. In this perspective, we address the identification and management of dual circulation and differential gas exchange through various clinical scenarios of venoarterial ECMO. Recognition of dual circulation, proper monitoring for differential gas exchange, and understanding the various strategies to resolve differential oxygenation and carbon dioxide may allow for more optimal patient management and improved clinical outcomes.

Gender Disparities in Presentation, Management, and Outcomes of Acute Pulmonary Embolism.

Pulmonary embolism (PE) is the third most common cause of cardiovascular death; however, gender disparities in PE remain understudied. All PE cases at a single institution between January 2013 and June 2019 were retrospectively reviewed. The clinical presentation, treatment modalities, and outcomes were compared between men and women using univariate and multivariate analyses adjusting for differences in baseline characteristics. A total of 1,345 patients were diagnosed with acute PE, of whom 56.3% were women (n = 757). Women had a significantly higher mean body mass index (29.4 vs 28.4) and a higher frequency of hypertension (53% vs 46%) and hormone use (6.6% vs 0%; all p <0.02). Men had a higher frequency of smoking (45% vs 33%, p <0.0001). Women had significantly lower PE severity index classifications (p = 0.0009). The rates of intensive care unit admission, vasopressor requirements, extracorporeal membrane oxygenation cannulation, and mechanical ventilation were similar between the genders. There was no significant difference in the treatment modality used between the genders. Although the risk factors and PE severity index class differed between the genders, there was no significant difference in resource utilization or treatment modality. Gender was also not a significant predictor of in-hospital mortality, moderate or severe bleeding, increased length of stay, or readmission in the study population.

Fibrotic-Like Pulmonary Radiographic Patterns Are Not Associated With Adverse Outcomes in COVID-19 Chronic Critical Illness.

OBJECTIVES: Pulmonary fibrosis is a feared complication of COVID-19. To characterize the risks and outcomes associated with fibrotic-like radiographic abnormalities in patients with COVID-19-related acute respiratory distress syndrome (ARDS) and chronic critical illness. DESIGN: Single-center prospective cohort study. SETTING: We examined chest CT scans performed between ICU discharge and 30 days after hospital discharge using established methods to quantify nonfibrotic and fibrotic-like patterns. PATIENTS: Adults hospitalized with COVID-19-related ARDS and chronic critical illness (> 21 d of mechanical ventilation, tracheostomy, and survival to ICU discharge) between March 2020 and May 2020. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We tested associations of fibrotic-like patterns with clinical characteristics and biomarkers, and with time to mechanical ventilator liberation and 6-month survival, controlling for demographics, comorbidities, and COVID-19 therapies. A total of 141 of 616 adults (23%) with COVID-19-related ARDS developed chronic critical illness, and 64 of 141 (46%) had a chest CT a median (interquartile range) 66 days (42-82 d) after intubation. Fifty-five percent had fibrotic-like patterns characterized by reticulations and/or traction bronchiectasis. In adjusted analyses, interleukin-6 level on the day of intubation was associated with fibrotic-like patterns (odds ratio, 4.40 per quartile change; 95% CI, 1.90-10.1 per quartile change). Other inflammatory biomarkers, Sequential Organ Failure Assessment score, age, tidal volume, driving pressure, and ventilator days were not. Fibrotic-like patterns were not associated with longer time to mechanical ventilator liberation or worse 6-month survival. CONCLUSIONS: Approximately half of adults with COVID-19-associated chronic critical illness have fibrotic-like patterns that are associated with higher interleukin-6 levels at intubation. Fibrotic-like patterns are not associated with longer time to liberation from mechanical ventilation or worse 6-month survival.

Extracorporeal membrane oxygenation in adults receiving haematopoietic cell transplantation: an international expert statement.

Combined advances in haematopoietic cell transplantation (HCT) and intensive care management have improved the survival of patients with haematological malignancies admitted to the intensive care unit. In cases of refractory respiratory failure or refractory cardiac failure, these advances have led to a renewed interest in advanced life support therapies, such as extracorporeal membrane oxygenation (ECMO), previously considered inappropriate for these patients due to their poor prognosis. Given the scarcity of evidence-based guidelines on the use of ECMO in patients receiving HCT and the need to provide equitable and sustainable access to ECMO, the European Society of Intensive Care Medicine, the Extracorporeal Life Support Organization, and the International ECMO Network aimed to develop an expert consensus statement on the use of ECMO in adult patients receiving HCT. A steering committee with expertise in ECMO and HCT searched the literature for relevant articles on ECMO, HCT, and immune effector cell therapy, and developed opinion statements through discussions following a Quaker-based consensus approach. An international panel of experts was convened to vote on these expert opinion statements following the Research and Development/University of California, Los Angeles Appropriateness Method. The Appraisal of Guidelines for Research and Evaluation statement was followed to prepare this Position Paper. 36 statements were drafted by the steering committee, 33 of which reached strong agreement after the first voting round. The remaining three statements were discussed by all members of the steering committee and expert panel, and rephrased before an additional round of voting. At the conclusion of the process, 33 statements received strong agreement and three weak agreement. This Position Paper could help to guide intensivists and haematologists during the difficult decision-making process regarding ECMO candidacy in adult patients receiving HCT. The statements could also serve as a basis for future research focused on ECMO selection criteria and bedside management.

Continuous near-infrared reflectance spectroscopy monitoring to guide distal perfusion can minimize limb ischemia surgery for patients requiring femoral venoarterial extracorporeal life support.

BACKGROUND: Patients requiring femoral venoarterial (VA) extracorporeal life support (ECLS) are at risk of distal lower limb hypoperfusion and ischemia of the cannulated leg. In the present study, we evaluated the effect of using continuous noninvasive lower limb oximetry with near-infrared reflectance spectroscopy (NIRS) to detect tissue hypoxia and guide distal perfusion catheter (DPC) placement on the rates of leg ischemia requiring surgical intervention. METHODS: We performed a retrospective analysis of patients who had undergone femoral VA-ECLS at our institution from 2010 to 2014 (pre-NIRS era) and 2017 to 2021 (NIRS era). Patients who had undergone cannulation during the 2015 to 2016 transition era were excluded. The baseline characteristics, short-term outcomes, and ischemic complications requiring surgical intervention (eg, fasciotomy, thrombectomy, amputation, exploration) were compared across the two cohorts. RESULTS: Of the 490 patients included in the present study, 141 (28.8%) and 349 (71.2%) had undergone cannulation before and after the routine use of NIRS to direct DPC placement, respectively. The patients in the NIRS cohort had had a greater incidence of hyperlipidemia (53.7% vs 41.1%; P = .015) and hypertension (71.4% vs 60%; P = .020) at baseline, although they were less likely to have been supported with an intra-aortic balloon pump before ECLS cannulation (26.9% vs 37.6%; P = .026). These patients were also more likely to have experienced cardiac arrest (22.9% vs 7.8%; P ≤ .001) and a pulmonary cause (5.2% vs 0.7%; P = .04) as an indication for ECLS, with ECLS initiated less often for acute myocardial infarction (15.8% vs 34%; P ≤ .001). The patients in the NIRS cohort had had a smaller arterial cannula size (P ≤ .001) and a longer duration of ECLS support (5 vs 3.25 days; P ≤ .001) but significantly lower rates of surgical intervention for limb ischemia (2.6% vs 8.5%; P = .007) despite comparable rates of DPC placement (49.1% vs 44.7%; P = .427), with only two patients (1.1%) not identified by NIRS ultimately requiring surgical intervention. CONCLUSIONS: The use of a smaller arterial cannula (≤15F) and continuous NIRS monitoring to guide selective insertion of DPCs could be a valid and effective strategy associated with a reduced incidence of ischemic events requiring surgical intervention.

Venovenous extracorporeal CO2 removal to support ultraprotective ventilation in moderate-severe acute respiratory distress syndrome: A systematic review and meta-analysis of the literature.

BACKGROUND: A strategy that limits tidal volumes and inspiratory pressures, improves outcomes in patients with the acute respiratory distress syndrome (ARDS). Extracorporeal carbon dioxide removal (ECCO2R) may facilitate ultra-protective ventilation. We conducted a systematic review and meta-analysis to evaluate the efficacy and safety of venovenous ECCO2R in supporting ultra-protective ventilation in moderate-to-severe ARDS. METHODS: MEDLINE and EMBASE were interrogated for studies (2000-2021) reporting venovenous ECCO2R use in patients with moderate-to-severe ARDS. Studies reporting ≥10 adult patients in English language journals were included. Ventilatory parameters after 24 h of initiating ECCO2R, device characteristics, and safety outcomes were collected. The primary outcome measure was the change in driving pressure at 24 h of ECCO2R therapy in relation to baseline. Secondary outcomes included change in tidal volume, gas exchange, and safety data. RESULTS: Ten studies reporting 421 patients (PaO2:FiO2 141.03 mmHg) were included. Extracorporeal blood flow rates ranged from 0.35-1.5 L/min. Random effects modelling indicated a 3.56 cmH2O reduction (95%-CI: 3.22-3.91) in driving pressure from baseline (p < .001) and a 1.89 mL/kg (95%-CI: 1.75-2.02, p < .001) reduction in tidal volume. Oxygenation, respiratory rate and PEEP remained unchanged. No significant interactions between driving pressure reduction and baseline driving pressure, partial pressure of arterial carbon dioxide or PaO2:FiO2 ratio were identified in metaregression analysis. Bleeding and haemolysis were the commonest complications of therapy. CONCLUSIONS: Venovenous ECCO2R permitted significant reductions in ∆P in patients with moderate-to-severe ARDS. Heterogeneity amongst studies and devices, a paucity of randomised controlled trials, and variable safety reporting calls for standardisation of outcome reporting. Prospective evaluation of optimal device operation and anticoagulation in high quality studies is required before further recommendations can be made.

Disparities in the treatment of cardiogenic shock: does sex matter?

OBJECTIVES: The use of extracorporeal life support for cardiogenic shock has significantly increased over the past decade. However, there are insufficient data for the presence of sex-associated outcomes differences. Our study assesses differences between male and female patients placed on venoarterial extracorporeal life support (VA-ECLS) for cardiogenic shock from an international database. METHODS: This is a multicentre, retrospective study on 9888 adult patients on VA-ECLS for cardiogenic shock from the Extracorporeal Life Support Organization registry from 2011 to 2019. The 1:1 nearest neighbour propensity score matching was performed. The primary end point was in-hospital mortality. Secondary end points include bleeding, infection and other complications. RESULTS: There were 6747 (68%) male patients and 3141 (32%) female patients. Male patients were more likely to have history of myocardial infarction, coronary artery disease, diabetes, chronic kidney disease and congestive heart failure. Female patients were more likely to be centrally cannulated. After propensity score matching, there was no difference seen in in-hospital mortality. In regards to complications, female patients were more likely to experience limb ischaemia, whereas males were more likely to receive renal replacement therapy and have longer hospital stays. Multivariable logistic regression confirmed sex was not independently associated with mortality. CONCLUSIONS: There was no difference in-hospital mortality between male and female patients receiving VA-ECLS for cardiogenic shock. Female patients were more likely to have limb ischaemia as a complication. Varying cannulation approaches for female patients should be further investigated.

Respiratory indications for ECMO: focus on COVID-19.

Extracorporeal membrane oxygenation (ECMO) is increasingly being used for patients with severe respiratory failure and has received particular attention during the coronavirus disease 2019 (COVID-19) pandemic. Evidence from two key randomized controlled trials, a subsequent post hoc Bayesian analysis, and meta-analyses support the interpretation of a benefit of ECMO in combination with ultra-lung-protective ventilation for select patients with very severe forms of acute respiratory distress syndrome (ARDS). During the pandemic, new evidence has emerged helping to better define the role of ECMO for patients with COVID-19. Results from large cohorts suggest outcomes during the first wave of the pandemic were similar to those in non-COVID-19 cohorts. As the pandemic continued, mortality of patients supported with ECMO has increased. However, the precise reasons for this observation are unclear. Known risk factors for mortality in COVID-19 and non-COVID-19 patients are higher patient age, concomitant extra-pulmonary organ failures or malignancies, prolonged mechanical ventilation before ECMO, less experienced treatment teams and lower ECMO caseloads in the treating center. ECMO is a high resource-dependent support option; therefore, it should be used judiciously, and its availability may need to be constrained when resources are scarce. More evidence from high-quality research is required to better define the role and limitations of ECMO in patients with severe COVID-19.

Early short course of neuromuscular blocking agents in patients with COVID-19 ARDS: a propensity score analysis.

BACKGROUND: The role of neuromuscular blocking agents (NMBAs) in coronavirus disease 2019 (COVID-19) acute respiratory distress syndrome (ARDS) is not fully elucidated. Therefore, we aimed to investigate in COVID-19 patients with moderate-to-severe ARDS the impact of early use of NMBAs on 90-day mortality, through propensity score (PS) matching analysis. METHODS: We analyzed a convenience sample of patients with COVID-19 and moderate-to-severe ARDS, admitted to 244 intensive care units within the COVID-19 Critical Care Consortium, from February 1, 2020, through October 31, 2021. Patients undergoing at least 2 days and up to 3 consecutive days of NMBAs (NMBA treatment), within 48 h from commencement of IMV were compared with subjects who did not receive NMBAs or only upon commencement of IMV (control). The primary objective in the PS-matched cohort was comparison between groups in 90-day in-hospital mortality, assessed through Cox proportional hazard modeling. Secondary objectives were comparisons in the numbers of ventilator-free days (VFD) between day 1 and day 28 and between day 1 and 90 through competing risk regression. RESULTS: Data from 1953 patients were included. After propensity score matching, 210 cases from each group were well matched. In the PS-matched cohort, mean (± SD) age was 60.3 ± 13.2 years and 296 (70.5%) were male and the most common comorbidities were hypertension (56.9%), obesity (41.1%), and diabetes (30.0%). The unadjusted hazard ratio (HR) for death at 90 days in the NMBA treatment vs control group was 1.12 (95% CI 0.79, 1.59, p = 0.534). After adjustment for smoking habit and critical therapeutic covariates, the HR was 1.07 (95% CI 0.72, 1.61, p = 0.729). At 28 days, VFD were 16 (IQR 0-25) and 25 (IQR 7-26) in the NMBA treatment and control groups, respectively (sub-hazard ratio 0.82, 95% CI 0.67, 1.00, p = 0.055). At 90 days, VFD were 77 (IQR 0-87) and 87 (IQR 0-88) (sub-hazard ratio 0.86 (95% CI 0.69, 1.07; p = 0.177). CONCLUSIONS: In patients with COVID-19 and moderate-to-severe ARDS, short course of NMBA treatment, applied early, did not significantly improve 90-day mortality and VFD. In the absence of definitive data from clinical trials, NMBAs should be indicated cautiously in this setting.

Veno-venous extracorporeal membrane oxygenation (vv-ECMO) for severe respiratory failure in adult cancer patients: a retrospective multicenter analysis.

PURPOSE: The question of whether cancer patients with severe respiratory failure benefit from veno-venous extracorporeal membrane oxygenation (vv-ECMO) remains unanswered. We, therefore, analyzed clinical characteristics and outcomes of a large cohort of cancer patients treated with vv-ECMO with the aim to identify prognostic factors. METHODS: 297 cancer patients from 19 German and Austrian hospitals who underwent vv-ECMO between 2009 and 2019 were retrospectively analyzed. A multivariable cox proportional hazards analysis for overall survival was performed. In addition, a propensity score-matched analysis and a latent class analysis were conducted. RESULTS: Patients had a median age of 56 (IQR 44-65) years and 214 (72%) were males. 159 (54%) had a solid tumor and 138 (47%) a hematologic malignancy. The 60-day overall survival rate was 26.8% (95% CI 22.1-32.4%). Low platelet count (HR 0.997, 95% CI 0.996-0.999; p = 0.0001 per 1000 platelets/µl), elevated lactate levels (HR 1.048, 95% CI 1.012-1.084; p = 0.0077), and disease status (progressive disease [HR 1.871, 95% CI 1.081-3.238; p = 0.0253], newly diagnosed [HR 1.571, 95% CI 1.044-2.364; p = 0.0304]) were independent adverse prognostic factors for overall survival. A propensity score-matched analysis with patients who did not receive ECMO treatment showed no significant survival advantage for treatment with ECMO. CONCLUSION: The overall survival of cancer patients who require vv-ECMO is poor. This study shows that the value of vv-ECMO in cancer patients with respiratory failure is still unclear and further research is needed. The risk factors identified in the present analysis may help to better select patients who may benefit from vv-ECMO.

Similarities in extracorporeal membrane oxygenation management across intensive care unit types in the United States: An analysis of the Extracorporeal Life Support Organization Registry.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) use in the United States occurs often in cardiothoracic ICUs (CTICU). It is unknown how it varies across ICU types. METHODS: We identified 10 893 ECMO runs from the Extracorporeal Life Support Organization (ELSO) Registry across 2018 and 2019. Primary outcome was ECMO case volume by ICU type (CTICU vs. non-CTICU). Adjusting for pre-ECMO characteristics and case mix, secondary outcomes were on-ECMO physiologic variables by ICU location stratified by support type. RESULTS: CTICU ECMO occurred in 65.1% and 55.1% (2018 and 2019) of total runs. A minority of total runs related to cardiac surgery procedures (CTICU: 21.7% [2018], 18% [2019]; non-CTICU: 11.2% [2018], 13% [2019]). After multivariate adjustment, non-CTICU ECMO for cardiac support associated with lower 4- and 24-h circuit flow (3.9 liters per minute [LPM] vs. 4.1 LPM, p < 0.0001; 4.1 LPM vs. 4.3 LPM, p < 0.0001); for respiratory support, lower on-ECMO mean fraction of inspired oxygen ([Fi O2 ], 67% vs. 69%, p = 0.02) and lower respiratory rate (14 vs. 15, p < 0.0001); and, for extracorporeal cardiopulmonary resuscitation (ECPR), lower ECMO flow rates at 24 h (3.5 LPM vs. 3.7 LPM, p = 0.01). CONCLUSIONS: ECMO mostly remains in CTICUs though a minority is associated with cardiac surgery. Statistically significant but clinically minor differences in on-ECMO metrics were observed across ICU types.

Postcardiotomy Extracorporeal Membrane Oxygenation: Narrative Review Navigating the Ethical Issues.

Postcardiotomy shock (PCS) is an uncommon and life-threatening surgical complication. Extracorporeal membrane oxygenation (ECMO) is the first line of mechanical circulatory support for treating PCS when medical therapies are insufficient. Reaching a "therapeutic ceiling" or a "bridge to nowhere" is a common clinical scenario in which medical avenues for recovery have been exhausted. These situations pose emotional and ethical challenges for patients, their surrogates, and clinicians. To shed light on these ethically challenging situations in PCS and potential approaches, the authors conducted a narrative review of the literature. Publications were utilized to describe current trends in the diagnosis and management of the patient with PCS, with particular emphasis on the therapeutic ceiling for life support. Most of the recommendations came from practice parameters or expert opinions to support specific interventions. The authors proposed a stepwise multidisciplinary approach to reduce PCS-associated ethical and emotional challenges. Their proposed algorithm was based on the likelihood of the need for ECMO support based on the mortality risk stratification of cardiac surgery. They suggested focused discussions around the commencement of ECMO or other life-sustaining therapies-ideally preoperatively at the time of consent-through shared decision-making and, subsequently, proactive multidisciplinary education and updates to the surrogate decision-makers relying on realistic prognosis and consideration of the patient wishes during the ECMO run.

Human factors in ECLS - A keystone for safety and quality - A narrative review for ECLS providers.

INTRODUCTION: Although the technology used for extracorporeal life support (ECLS) has improved greatly in recent years, the application of these devices to the patient is quite complex and requires extensive training of team members both individually and together. Human factors is an area that addresses the activities, contexts, environments, and tools which interact with human behavior in determining overall system performance. HYPOTHESIS: Analyses of the cognitive behavior of ECLS teams and individual members of these teams with respect to the occurrence of human errors may identify additional opportunities to enhance safety in delivery of ECLS. RESULTS: The aim of this article is to support health-care practitioners who perform ECLS, or who are starting an ECLS program, by establishing standards for the safe and efficient use of ECLS with a focus on human factor issues. Other key concepts include the importance of ECLS team leadership and management, as well as controlling the environment and the system to optimize patient care. CONCLUSION: Expertise from other industries is extrapolated to improve patient safety through the application of simulation training to reduce error propagation and improve outcomes.

Bleeding and Thrombotic Events During Extracorporeal Membrane Oxygenation for Postcardiotomy Shock.

BACKGROUND: Anticoagulation therapy management during venoarterial extracorporeal membrane oxygenation (ECMO) is particularly difficult in postcardiotomy shock patients given a significant bleeding risk. We sought to determine the effect of anticoagulation treatment on bleeding and thrombosis risk for postcardiotomy shock patients on ECMO. METHODS: We retrospectively reviewed patients who received ECMO for postcardiotomy shock from July 2007 through July 2019. Characteristics of patients who had bleeding and thrombosis were investigated, and risk factors were assessed by multilevel logistic regression. RESULTS: Of the 152 patients who received ECMO for postcardiotomy shock, 33 (23%) had 40 thrombotic events and 64 (45%) had 86 bleeding events. Predictors of bleeding were intraoperative packed red blood cell transfusion (odds ratio [OR] 1.05; 95% confidence interval [CI], 1.01 to 1.09), platelet transfusion (OR 1.10; 95% CI, 1.05 to 1.16), international normalized ratio (OR 1.18; 95% CI, 1.02 to 1.37), and activated partial thromboplastin time greater than 60 seconds (OR 2.32; 95% CI, 1.14 to 4.73). Predictors of thrombosis were anticoagulant use (OR 0.39; 95% CI, 0.19 to 0.79), surgical venting (OR 3.07; 95% CI, 1.29 to 7.31), hemoglobin (OR 1.38; 95% CI, 1.06 to 1.79), and central cannulation (OR 2.06; 95% CI, 1.03 to 4.11). The daily predicted probability of thrombosis was between 0.075 and 0.038 for patients who did not receive anticoagulation and decreased to between 0.030 and 0.013 for patients who received anticoagulation treatment at activated partial thromboplastin times between 25 and 80 seconds. CONCLUSIONS: Anticoagulation therapy can reduce thromboembolic events in postcardiotomy shock patients on ECMO, but bleeding risk may outweigh this benefit at activated partial thromboplastin times greater than 60 seconds.

Sex differences in patients with cardiogenic shock requiring extracorporeal membrane oxygenation.

OBJECTIVE: Our study assesses differences between male and female patients placed on venoarterial extracorporeal membrane oxygenation for cardiogenic shock. METHOD: We retrospectively analyzed 574 adult patients placed on venoarterial extracorporeal membrane oxygenation for cardiogenic shock at our institution between January 2007 and December 2018. Baseline characteristics and outcomes were assessed. Propensity score matching was used to compare outcomes. The primary end point was in-hospital mortality. Secondary outcomes include limb ischemia, limb ischemia interventions, distal perfusion cannula placement, stroke, bleeding, and continuous venovenous hemofiltration initiation. RESULTS: There were 394 male patients (69%) and 180 female patients (31%). After adjusting for baseline differences, propensity score matching compared 171 male patients with 171 female patients. No difference was seen between men and women in in-hospital mortality (60.2% vs 56.7%; P = .59), limb ischemia (47.4% vs 45.6%; P = .83), limb ischemia surgery (15.2% vs 12.9%; P = .64), bleeding (49.7% vs 49.1%; P = 1), continuous venovenous hemofiltration initiation (39.2% vs 32.7%; P = .26), and stroke (8.2% vs 9.4%; P = .85). Multivariable logistic regression showed that female patients who died were more likely to have had chronic kidney disease (odds ratio [OR], 2.67; 95% confidence interval [CI], 1.09-6.53; P = .032) than surviving women. Male patients who died were more likely to have had coronary artery disease (OR, 2.25; 95% CI, 1.34-3.78; P = .002) and higher lactate levels (OR, 1.14; 95% CI, 1.08-1.21; P < .001) than surviving men. Women with cardiac transplant primary graft dysfunction were more likely to survive (OR, 0.04; 95% CI, 0.01-0.27; P = .001), whereas men with cardiac transplant primary graft dysfunction were less likely to survive (OR, 0.28; 95% CI, 0.11-0.71; P = .007), than patients with other shock etiologies. CONCLUSIONS: After adjusting for baseline difference, there was no difference in outcomes between male and female patients despite differing risk profiles for in-hospital mortality.

Lung transplantation disparities based on diagnosis for patients bridging to transplant on extracorporeal membrane oxygenation.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is increasingly utilized as a bridge to lung transplantation, but ECMO status is not explicitly accounted for in the Lung Allocation Score (LAS). We hypothesized that among waitlist patients on ECMO, patients with pulmonary arterial hypertension (PAH) would have lower transplantation rates. METHODS: Using United Network for Organ Sharing data, we conducted a retrospective cohort study of patients who were ≥12 years old, active on the lung transplant waitlist, and required ECMO support from June 1, 2015 through June 12, 2020. Multivariable competing risk analysis was used to examine waitlist outcomes. RESULTS: 1064 waitlist subjects required ECMO support; 40 (3.8%) had obstructive lung disease (OLD), 97 (9.1%) had PAH,138 (13.0%) had cystic fibrosis (CF), and 789 (74.1%) had interstitial lung disease (ILD). Ultimately, 671 (63.1%) underwent transplant, while 334 (31.4%) died or were delisted. The transplant rate per person-years on the waitlist on ECMO was 15.41 for OLD, 6.05 for PAH, 15.66 for CF, and 15.62 for ILD. Compared to PAH patients, OLD, CF, and ILD patients were 78%, 69%, and 62% more likely to undergo transplant throughout the study period, respectively (adjusted SHRs 1.78 p = 0.007, 1.69 p = 0.002, and 1.62 p = 0.001). The median LAS at waitlist removal for transplantation, death, or delisting were 75.1 for OLD, 79.6 for PAH, 91.0 for CF, and 88.3 for ILD (p < 0.001). CONCLUSIONS: Among patients bridging to transplant on ECMO, patients with PAH had a lower transplantation rate than patients with OLD, CF, and ILD.

A Standardized Approach Improves Outcomes of Extracorporeal Membrane Oxygenation for Postcardiotomy Shock.

Postcardiotomy shock (PCS) has historically been associated with substantial morbidity and mortality. Mortality at discharge is reportedly more than 60%. We investigated the outcomes of our standardized approach to veno-arterial extracorporeal membrane oxygenation (ECMO) management for PCS. We retrospectively reviewed 60 consecutive PCS patients who required ECMO following major cardiac surgery from January 2017 to September 2019. Index surgery included CABG (n = 10), valve (n = 23), valve and CABG (n = 12), root surgery (n = 10), and other (n = 5). Median lactate level, systolic blood pressure, and mean pulmonary artery pressure before ECMO were 4.0 mmol/L, 80 mm Hg, and 29 mm Hg, respectively. Fifty-nine patients (98%) were on two vasopressors, and 54 (90%) were on at least two inotropes. Vasoactive-Inotropic Score was 30 (IQR, 25-49). Eighty percent of patients received peripheral ECMO. Median ECMO flow index was 1.61 (IQR, 1.4-2.0) L/min/m2. Anticoagulation was not given in 12 (20%) patients during ECMO support. Major adverse events included chest re-exploration (15%), stroke (6.7%), renal replacement therapy (22%), and limb ischemia (5%). In-hospital mortality was 33%. This study suggests that a standardized approach with a dedicated ECMO team is feasible and may improve outcomes of PCS.

An appraisal of respiratory system compliance in mechanically ventilated covid-19 patients.

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.