In this study, we investigated 72 critically ill patients with confirmed COVID–19 pneumonia requiring mechanical ventilation. As compared with reported mortality rates of 62% (Wuhan, China), 67% (Washington State, USA)8, and 88% (New York, USA)7, we hereby present our mortality rate of 54.2% (or our 28-day mortality rate of 52.7%). This study took place in a large community hospital located in a pandemic epicenter area. We attribute our relative low mortality rate to the combination of early intubation and usage of ARDSnet protocol 11,12.
Through detailed data analysis of demographic characteristics and underlying medical conditions, significant connections with clinical outcomes were established. We found younger patients who had higher BMI had a worse clinical outcome, reinforcing the already known correlation of obesity and severe disease2. Despite this, neither age or BMI significantly correlated with mortality or successful extubation rates. Although the literature recognizes a linear relationship between elderly and obese patients with severity of disease 5,7, we found that among those who were already intubated (critically ill) the above risk factors did not predict outcomes. The same findings are also applicable to gender and race.
Chronic conditions such as underlying lung disease, cardiovascular disease, diabetes mellitus, and hypertension also seem to increase the risk for severe COVID–19 2,4. Otherwise, we found only hyperlipidemia was strongly associated with risk of death, and not extubation failure.
In regard to laboratory data, we identified statistically significant predictors for worse outcomes. Patients with higher CRP levels, BUN, and creatinine during hospitalization were at increased risk of death and lower successful extubation rates. The same association applies to those who had lower PaO2/ FiO2 ratios, reestablishing findings from Wuhan, China 4.
Emerging therapies along with supportive therapy, is the consensus for treatment worldwide3. In our cohort, 22 (30.5%) participants required hemodialysis. However, this requirement did not correlate with outcomes. Hemodialysis did not predict death, liberation of ventilator, or tracheostomy. The majority (70.8%) received vasopressors, typically associated with greater mortality, but not with failed extubation. We find these results to be unique, given no available data on dialysis or vasopressors usage for comparison to our knowledge.
Our study has some limitations. First, our sample size of 72 patients is rather small. Yet, we aimed to analyze an exclusive cohort, limited to only intubated patients. This adds reliability to disease severity. We hope the findings presented here will encourage a larger cohort study. Second, this study was performed in a single-center. However, this fact could potentially reduce bias on protocol adherence, increasing the power of our reported mortality rate. Third, this is a retrospective study. Our data permit a preliminary assessment of mortality and successful extubation rates in patients with COVID–19 who are mechanically ventilated. Larger studies are needed to overcome our limitations, and further our knowledge regarding this disease.
In conclusion, although the mortality of critically ill patients is still high, our rate was significantly lower when compared to other studies. We believe this was a consequence of early intubation in conjunction with the usage of the ARDSnet protocol. We also observed patients with hyperlipidemia, higher CRP, renal failure, or those requiring vasopressor use had worse outcomes.