In a recent study published on search field *, Researchers report that plasma interleukin (IL)-6 levels in patients with acute respiratory distress syndrome (ARDS) due to coronavirus disease 2019 (COVID-19) can predict early withdrawal from mechanical ventilation (MV).
Acute respiratory distress syndrome is characterized by acute inflammatory lung injury and poor oxygenation resulting in rheumatoid arthritis in patients under intensive care. ARDS can be due to trauma, infection, pneumonia, a history of blood transfusion, sepsis, or even lung injury caused by the ventilator itself. The mortality rate during hospitalization is high (40% – 50%), and increases with the severity of acute respiratory distress syndrome. Several studies have evaluated the effectiveness of corticosteroids in modulating excessive inflammation, but their efficacy remains controversial. However, administration of dexamethasone can shorten the duration of MV and reduce mortality in those with moderate or severe acute respiratory distress syndrome.
Furthermore, critical COVID-19 patients requiring MV have been exposed to acute respiratory distress syndrome with a high in-hospital mortality rate. Early use of remdesivir and dexamethasone has been associated with a reduction in MV duration and in-hospital mortality in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) patients. Treating patients with acute respiratory distress syndrome is challenging, since indicators for predicting a therapeutic response such as MV withdrawal remain undetermined.
Study and results
The researchers investigated whether IL-6 levels could indicate early withdrawal of patients with acute respiratory distress syndrome from MV in the current study.
Between February 2020 and July 2021, approximately 268 COVID-19 patients were recruited, of whom 149 were excluded due to lack of data or consent to participate. Of the 119 MV patients with SARS-CoV, 81% were male, and the median period from symptom onset to intubation was seven days. About 20%-30% of them have various diseases such as diabetes, hypertension, chronic kidney disease.
Each patient underwent anticoagulant therapy, and 83% was given remdesivir. 52 patients were treated with dexamethasone, which persisted during MV. In general, the duration of medium effort use was 13.9 days. Thirteen patients required extracorporeal membrane oxygenation (ECMO) or died during hospitalization.
Clinical characteristics were evaluated and compared in two groups: one in which patients were treated with a steroid and the other in which a non-steroidal one. There were fewer elderly males in the steroid-treated group than in the non-steroid patients. The duration of MV symptoms was shorter for steroid patients. Fewer patients treated with steroids have diabetes mellitus. No significant differences were observed in platelet count, creatinine and bilirubin levels, or remdesivir use across the two groups. However, the combined ECMO-use rate of in-hospital mortality was significantly lower in dexamethasone-treated patients than in untreated patients.
Plasma levels of C-reactive protein (CRP) and IL-6 were estimated in 40 steroid-treated patients and 16 non-steroid patients on days 1, 4, and 7 of MV use. Those treated with dexamethasone had significantly lower CRP and IL-6 than non-steroid patients. The authors note that circulating levels of IL-6 on day 7 of MV use closely correlated with duration of MV, followed by the percentage change in IL-6 or CRP levels between days 1 and 7, CRP levels on day 7, and IL-6 levels on day the first. No association was observed for IL-6 levels on Day 4, CRP levels on Days 1 and 4, or even the difference between CRP or IL-6 levels between Days 1 and 7. Receiver operating characteristic (ROC) curve analysis found that IL- 6 at day 7 post intubation in steroid-treated patients was predictive of MV withdrawal within 11 days, followed by a percentage change in IL-6 or CRP levels between day 1 and 7.
The researchers are said to be the first to note that plasma IL-6 levels can serve as early predictive indicators of withdrawal from invasive MV use in SARS-CoV-2 patients with acute respiratory distress syndrome, who were treated with dexamethasone. Furthermore, absolute levels and percentage change in CRP were associated with early MV withdrawal; However, due to the small sample size, a statistical comparison between the predicted values of IL-6 and CRP is not possible.
Some limitations of the study include its retrospective nature with missing data, smaller sample size, and the lack of standard steroid treatment in the study population. Future research should test the prospective application of IL-6 in multicenter and steroid-treated patients with ARDS for many reasons.
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