Thank you everyone. Thank you for coming to my presentation today. My name is Chengda. Today I will be presenting a few findings from our COVID-19 critical care patients registry. And those findings may help with clinical decision in the early phase of ECMO initiation on the patients. So the title of my presentation is length of pre-ECMO mechanical ventilation is not associated with mortality in patients with COVID-19. And the presentation is part of the STAR research presentations pulmonary. I have nothing to disclose. This is a little bit introduction about myself. I am intensivist and a clinical informatics fellow from Oregon Health and Science University. I am training internal medicine, critical care medicine, and also clinical informatics. The learning objectives for today is hopefully from our data analysis that I can help you better understand the patient factors that are associated with hospital mortality among COVID-19 patients who received ECMO. And this is the structure for today's presentation. I will first talk about the backgrounds and the methods results. I will touch a little bit on our limitations and then conclusions and a little bit discussion over the reasoning. So first of all, about the background, why are we doing this research? So when the patients develops ARDS from COVID-19, and one of the life support measure is called ECMO. And in order to decide which patients may benefit from ECMO the most, studies and data's surrounding like which type of patients may have a worse prognosis and which types of patient may have a better prognosis are very helpful in terms of decision-making whether or not a patient should be put on ECMO. This question has been studied in the past. Actually, we have data from previous influenza epidemic and we already, several studies showed that delayed initiation of ECMO was actually associated with higher mortality. And why is that? Even though ECMO is a purely life support measure, it does allow ultra-long protective ventilation, which will help with lung recovery. So if you can start ECMO earlier, the lung can get rest more and there's a better chance that the patient's lung can improve. Our hypothesis before we did all the analysis and the findings of our study at the beginning was actually that prolonged invasive mechanical ventilation or IMV prior to ECMO was associated with higher mortality in patients with COVID-19. So here's our methods. The data source is from our COVID-19 critical care consortium which is a prospective international multi-center registry. All of the patients had a diagnosis of COVID-19 and received a mechanical ventilation as well as ECMO. For exclusion, we did exclude those patients who were intubated prior to transfer to a study site just because if they were intubated and put on the mechanical ventilation prior to arriving to a study site, we really don't have much data to support like how many days and to track like how many days that the patient has been on mechanical ventilation. So the data might not be reliable in those patients who are excluded. This is our statistical methods. In order to find out which variables are significantly associated with death, we built this Cox proportional hazard models with all of this eight input variables. And our primary interest is on the number of days on mechanical ventilation prior to ECMO initiation. We did include seven other covariance in our model to make sure that we can control the confounders as much as possible. And the association between death and one of the factors is it's a purely and close to causal relationship. And after we were able to build this model and we can look at the models, variables and each rival will come up with a hazard ratio and that's 95% confidence interval of the hazard ratio. And based on those number, then you will be able to tell if one of the or one or two or multiple factors are significantly associated with death. This is the result. The first part on this page, I'm gonna talk about the descriptive analysis. Basically, we were able to identify 593 patients from the 107 study sites in 25 countries. All of those nearly 600 patients, their median age is 50. About 220 of patients had obesity, 223 patients had hypertension, 24 patients had chronic pulmonary disease. And in terms of the number of days prior to ECMO, patients spent a median of 3.68 days in the ICU prior to be candidated for ECMO. And patients received a mechanical ventilation and a median of 2.49 days prior to initiation of ECMO. And overall, the amount of all of those 600 patients, 280 patients died. The mortality is around 47.2%. So here is the main part of our analysis. We built this model and we looked at all of the parameters, the input variables had the ratio. And based on our numbers, and we were able to determine that only two factors, which is gender and age, are the significant predictive effects on death. For gender, you can look at this for the second line, second row of this table, we can see gender being male has had a ratio of 1.54 with a 95% confidence interval between 1.13 to 2.09. So this gender being male has like 1.5 times elevated risk for mortality. And the rest of the categorical factors did not show significant association with death. In terms of age, and you can see a significant trend from the age of zero to age of 75 and above, the average hazard ratio goes, first is below one, and then we have, and then after around age 52, the patient, the confidence interval actually crosses one, and stays all above one area. So that means the older age, likely from above 52, 53 in this range, is actually compared, when it compares with a younger age, it does comes with a significant predictive effect on the death. So those are the two factors that we found that are significant. How about the one that we are really interested in, which is the number of days on mechanical ventilation prior to ECMO? This factor actually does not predict death in our model. And look at here, we do have a lot more data for patients like from mechanical ventilation from zero days to 20 days. And you can see the confidence interval is reasonably narrowed between in this days range, and the average number is actually staying around one. And it never crosses, and the confidence interval never stays above or below one, no matter from zero to 20 days. And above 20 days, we really don't have too many patients. And you can see the gray area, the confidence interval really getting very large, and the estimates is not reliable enough for us to tell for patients who are on super longer days of more than 20 days of mechanical ventilation, whether or not they are more likely to death or not. So those are above our results findings from our analysis. Our analysis does come with the limitations. First of all, this is a retrospective analysis of this COVID-19 critical care consortium data. And given the retrospective nature, one of the most common and hard to deal with analytical limitations is actually the confounders. And it's basically impossible to identify and track and include all of the confounders in your analysis. And in our case, we were able to identify several confounders. One of them actually quite important is that we don't have enough data to track the ventilator settings prior and after the ECMO initiation. So therefore, this factor is not included in our model. And you can imagine if there is a variations in terms of clinical practice, some centers may continue with their rescue mechanical ventilation vent settings. And even after ECMO cannulation, the effects of the benefits of ECMO on lungs may not be that significant among those patients in the centers. So those are the heterogeneity of our data. And I think it does play a role in the part of the reason why we did not find any significant association between number of days on mechanical ventilation prior to ECMO and overall mortality. So here comes our conclusions. Overall, among all the patients with COVID-19 who received ECMO, the length of pre-ECMO invasive mechanical ventilation was not associated with hospital mortality. And however, I did talk about there are possibilities of confounding factors and further studies are needed to evaluate the ventilator settings before and after ECMO initiation, because those are some of the important confounding factors that we were not able to track in our own studies here. And above are all my presentation. Thank you for all the co-authors and who has provided me great advice and analytical support and guidance on this work. And thank you to the whole team of COVID-19 Great Care Consortium. And without their effort, we will never be able to find that many large-scale, high-quality COVID-19 ECMO patients' data. And about tomorrow will be the Chinese New Year. And I hope everyone will enjoy the year of the rabbit. Thank you very much. And please feel free to email me if you have any questions. Thank you. Bye-bye.

COVID-19

critical care patients

pre-ECMO mechanical ventilation

mortality

gender