inclusion criteria: * age 18 - 80 y.o. since over eighties are very fragile patients, a lot of confounding unpredictable events may interfere with the trial analyses; thus, these patients will be excluded from this exploratory proof-of-concept trial; * covid-19 diagnosis through swab within 14 days from the beginning of symptoms * hospitalization for moderate to severe ards (as determined by pao2/fio2 ≤300 mmhg at admission) * serum concentration of potassium ≤4.5 meq/l * consent to participate

inclusion criteria: * age 18 - 80 y.o. since over eighties are very fragile patients, a lot of confounding unpredictable events may interfere with the trial analyses; thus, these patients will be excluded from this exploratory proof-of-concept trial; * covid-19 diagnosis through swab within 14 days from the beginning of symptoms * hospitalization for moderate to severe ards (as determined by pao2/fio2 ≤300 mmhg at admission) * serum concentration of potassium ≤4.5 meq/l * consent to participate

inclusion criteria: - age 18 - 80 y.o. since over eighties are very fragile patients, a lot of confounding unpredictable events may interfere with the trial analyses; thus, these patients will be excluded from this exploratory proof-of-concept trial; - covid-19 diagnosis through swab within 14 days from the beginning of symptoms - hospitalization for moderate to severe ards (as determined by pao2/fio2 ≤300 mmhg at admission) - serum concentration of potassium ≤4.5 meq/l - consent to participate

inclusion criteria: - age 18 - 80 y.o. since over eighties are very fragile patients, a lot of confounding unpredictable events may interfere with the trial analyses; thus, these patients will be excluded from this exploratory proof-of-concept trial; - covid-19 diagnosis through swab within 14 days from the beginning of symptoms - hospitalization for moderate to severe ards (as determined by pao2/fio2 ≤300 mmhg at admission) - serum concentration of potassium ≤4.5 meq/l - consent to participate