Background: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) pump flow is crucial for maintaining organ perfusion in patients with cardiogenic shock, but VA-ECMO pump flow optimization remains as a clinical challenge. This study aimed to investigate the response of sublingual microcirculation to changes in VA-ECMO pump flow.Methods: Sublingual microcirculation was measured before and after changing VA-ECMO pump flow according to the treatment plan of ECMO team within 24 h and at 24-48 h after VA-ECMO placement. In clinical events of increasing VA-ECMO pump flow, those events with increased perfused vessel density (PVD) were grouped into group A, and the others were grouped into group B. In clinical events of decreasing VA-ECMO pump flow, those events with increased PVD were grouped into group C, and the others were grouped into group D.Results: Increased PVD was observed in 60% (95% CI, 38.5–81.5%) of the events with increasing VA-ECMO pump flow. The probability of increasing PVD after increasing VA-ECMO pump flow were higher in the events with a PVD < 15 mm/mm2 at baseline than those with a PVD ≥ 15 mm/mm2 [100% (95% CI, 54.1–100%) vs. 42.9% (95% CI, 17.7–71.1%), P = 0.042]. Other microcirculatory and hemodynamic parameters at baseline did not differ significantly between group A and B or between group C and D.Conclusion: This study revealed contradictory and non-contradictory responses of sublingual microcirculation to changes in VA-ECMO pump flow. Tandem measurements of microcirculation before and after changing VA-ECMO pump flow may help to ensure a good microcirculation.

Chest auscultation is the first procedure performed to detect endotracheal tube malpositioning but conventional stethoscopes do not conform to the personal protective equipment (PPE) protocol during the COVID-19 pandemic. This double-blinded randomized controlled trial evaluated the feasibility of using ear-contactless electronic stethoscope to identify endobronchial blocker established selective lung ventilation, simulating endobronchial intubation during thoracic surgery with full PPE. Conventional and electronic auscultation was performed without and with full PPE, respectively, of 50 patients with selective lung ventilation. The rates of correct ventilation status detection were 86 and 88% in the conventional and electronic auscultation groups (p = 1.00). Electronic auscultation revealed a positive predictive value of 87% (95% CI 77 to 93%), and a negative predictive value of 91% (95% CI 58 to 99%), comparable to the results for conventional auscultation. For detection of the true unilateral lung ventilation, the F1 score and the phi were 0.904 and 0.654, respectively for conventional auscultation; were 0.919 and 0.706, respectively for electronic auscultation. Furthermore, the user experience questionnaire revealed that the majority of participant anesthesiologists (90.5%) rated the audio quality of electronic lung sounds as comparable or superior to that of conventional acoustic lung sounds. In conclusion, electronic auscultation assessments of ventilation status as examined during thoracic surgery in full PPE were comparable in accuracy to corresponding conventional auscultation assessments made without PPE. Users reported satisfactory experience with the electronic stethoscope.

Background: Extracorporeal membrane oxygenation (ECMO) life support has become an integral part of intensive care. The endotoxin activity assay (EAA) is a useful test to measure endotoxemia severity in whole blood. To date, no information is available regarding the EAA levels and their effect on clinical outcomes in critically ill patients with ECMO support.Methods: This prospective observational pilot study enrolled adult critically ill patients with ECMO support from August 2019 to December 2020. The EAA levels were measured within 24 h (T1), and at 25–48 (T2), 49–72 (T3), and 73–96 h (T4) after ECMO initiation. This study primarily aimed to investigate the incidence of high EAA levels (≥0.6) at each time point. Subsequent exploratory analyses were conducted to compare the EAA levels of venoarterial ECMO (VA-ECMO) patients between 30-day survivors and non-survivors. Post-hoc analysis was performed to compare the clinical outcomes of VA-ECMO patients with elevated EAA levels at T3 (vs. T1) and those without elevated EAA levels.Results: A total of 39 VA-ECMO patients and 15 venovenous ECMO (VV-ECMO) patients were enrolled. At T1, the incidence of high EAA level (≥0.6) was 42% in VV-ECMO patients and 9% in VA-ECMO patients (P = 0.02). At T2, the incidence of high EAA level was 40% in VV-ECMO patients and 5% in VA-ECMO patients (P = 0.005). In VA-ECMO patients, EAA levels at T3 were significantly higher in 30-day non-survivors than in survivors (median [interquartile range]: 0.49 [0.37–0.93] vs. 0.31 [0.19–0.51], median difference 0.16 [95% confidence interval [CI], 0.02–0.31]; P = 0.024). Moreover, VA-ECMO patients with elevated EAA levels at T3 (vs. T1) had lower 30-day survival than patients without elevated EAA levels (39 vs. 83%, P = 0.026) and fewer ECMO free days by day 30 (median: 3 vs. 23 days, median difference 12 days [95% CI, 0–22]; P = 0.028).Conclusions: A certain proportion of patients experienced high EAA levels (≥0.6) after VV-ECMO or VA-ECMO initiation. VA-ECMO patients with an elevated EAA level at 49–72 h were associated with poor clinical outcomes.

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Background: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) pump flow is crucial for maintaining tissue and organ perfusion in patients with cardiogenic shock. Determining the optimal VA-ECMO pump flow rate to maintain adequate tissue perfusion remains a clinical challenge. Poor microcirculation is associated with higher mortality in patients using VA-ECMO. Change in VA-ECMO pump flow is expected to result in a coherent change in microcirculatory blood flow, but this has not been investigated. This study investigated the effect of altering VA-ECMO pump flow rate on sublingual microcirculation. Methods: Sublingual microcirculation images were recorded using an incident dark-field hand held vital microscope at two time points, within 24 h (T1) and at 24-48 h (T2) after VA-ECMO placement. Microcirculation was measured before and 5 minutes after the changes in VA-ECMO pump flow rate at each time point. Events of changing VA-ECMO pump flow rate at T1 and T2 were divided into four groups according to changes in perfused vessel density (PVD): Group A, increased pump flow rate and increased or sustained PVD; Group B, increased pump flow rate and decreased PVD; Group C, decreased pump flow rate and increased or sustained PVD; and Group D, decreased pump flow rate and decreased PVD. The microcirculatory parameters, clinical parameters, and prognosis of each subgroup were recorded. Clinical parameters on 14-day and 28-day survivors and non-survivors were also compared. Results: A total of 25 patients were enrolled, and 38 events with good-quality images at T1 and T2 were categorized. Opposing response of microcirculation was observed in 43.5% of events when VA-ECMO pump flow rate was increased. Microcirculation was decreased in 33.4% of events when VA-ECMO pump flow rate was reduced. No predictive values in microcirculatory or macrocirculatory parameters before changing VA-ECMO pump flow rate were identified. Conclusions: Changes in VA-ECMO pump flow rate may have opposing effects on sublingual microcirculatory functional capillary density. We suggest that tandem measurements of microcirculation before and after altering the VA-ECMO pump flow may help to ensure optimal tissue perfusion.