5. A study was conducted in Washington during February 2020 to identify characteristics of critically ill COVID-19 patients (Bhatraju et al., 2020). Below is the abstract from the published peer-reviewed journal article.

BACKGROUND

Community transmission of coronavirus 2019 (Covid-19) was detected in the state of Washington in February 2020.

METHODS

We identified patients from nine Seattle-area hospitals who were admitted to the intensive care unit (ICU) with confirmed infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Clinical data were obtained through review of medical records. The data reported here are those available through March 23, 2020. Each patient had at least 14 days of follow-up.

RESULTS

We identified 24 patients with confirmed Covid-19. The mean (SD) age of the patients was 6418 years, 63% were men, and symptoms began 74 days before admission. The most common symptoms were cough and shortness of breath; 50% of patients had fever on admission, and 58% had diabetes mellitus. All the patients were admitted for hypoxemic respiratory failure; 75% (18 patients) needed mechanical ventilation. Most of the patients (17) also had hypotension and needed vasopressors. No patient tested positive for influenza A, influenza B, or other respiratory viruses. Half the patients (12) died between ICU day 1 and day 18, including 4 patients who had a do-not-resuscitate order on admission. Of the 12 surviving patients, 5 were discharged home, 4 were discharged from the ICU but remained in the hospital, and 3 continued to receive mechanical ventilation in the ICU.

CONCLUSIONS

During the first 3 weeks of the Covid-19 outbreak in the Seattle area, the most common reasons for admission to the ICU were hypoxemic respiratory failure leading to mechanical ventilation, hypotension requiring vasopressor treatment, or both. Mortality among these critically ill patients was high. (Funded by the National Institutes of Health.)

a.What type of study design was used? Briefly justify your response. (5 points)

b.Briefly describe two strengths and two limitations of the study design identified in part a.

(10 points)