2.1. Participants
In this study, a total of 202 patients who were admitted to between February 2020 to December 2020 were reviewed. These patients were treated with standard methods or IVIG added to standard care. Inclusion criteria were COVID-19 confirmation with real-time polymerase chain reaction (PCR), significant pulmonary findings compatible with radiographic imaging and critically ill patients in ICU.
Critically ill patients were those with less than 90% oxygen saturation level with Non-rebreather mask, those who needed noninvasive ventilation (NIV) or intubation. Exclusion criteria were age under 18 years old, pregnancy, patients with incomplete data, non-ICU patients, those who participated in other clinical trials or received nonstandard treatment due to national or regional protocol and those who received less than five grams of IVIG.