(1) patients intubated for more than 72 hours from initiation of the treatment gas; (2) subjects enrolled in another interventional research study; (3) physician of record opposed to enrolling the patient due to perceived safety concerns; or any condition that does not allow the protocol to be followed safely; (4) subjects with past medical history of lung malignancy or pneumonectomy or lung transplant; (5) subjects receiving a tidal volume \< 3 cc/kg of ideal body weight at the time of enrollment; (6) subjects with severe burns involving more than 40% of total body surface area; (7) subjects that have experienced cardiac arrest with cpr for longer than 30 minutes; (8) subjects with a presumed severe deficit in cerebral function with fixed dilated pupil; (9) subjects receiving renal replacement therapy at the time of enrollment; (10) subjects who have an impaired ability to ventilate without assistance; (11) subjects who have a history of malignancy or other irreversible disease/conditions with a 6-month mortality \> 50%; (12) subjects not fully committed to full support at the time of enrollment; (13) subject receiving inhaled nitric oxide gas prior to enrollment; (14) subject's hospital admission unrelated to covid-19.

(1) patients intubated for more than 72 hours from initiation of the treatment gas; (2) subjects enrolled in another interventional research study; (3) physician of record opposed to enrolling the patient due to perceived safety concerns; or any condition that does not allow the protocol to be followed safely; (4) subjects with past medical history of lung malignancy or pneumonectomy or lung transplant; (5) subjects receiving a tidal volume \< 3 cc/kg of ideal body weight at the time of enrollment; (6) subjects with severe burns involving more than 40% of total body surface area; (7) subjects that have experienced cardiac arrest with cpr for longer than 30 minutes; (8) subjects with a presumed severe deficit in cerebral function with fixed dilated pupil; (9) subjects receiving renal replacement therapy at the time of enrollment; (10) subjects who have an impaired ability to ventilate without assistance; (11) subjects who have a history of malignancy or other irreversible disease/conditions with a 6-month mortality \> 50%; (12) subjects not fully committed to full support at the time of enrollment; (13) subject receiving inhaled nitric oxide gas prior to enrollment; (14) subject's hospital admission unrelated to covid-19.

(1) patients intubated for more than 72 hours from initiation of the treatment gas; (2) subjects enrolled in another interventional research study; (3) physician of record opposed to enrolling the patient due to perceived safety concerns; or any condition that does not allow the protocol to be followed safely; (4) subjects with past medical history of lung malignancy or pneumonectomy or lung transplant; (5) subjects receiving a tidal volume < 3 cc/kg of ideal body weight at the time of enrollment; (6) subjects with severe burns involving more than 40% of total body surface area; (7) subjects that have experienced cardiac arrest with cpr for longer than 30 minutes; (8) subjects with a presumed severe deficit in cerebral function with fixed dilated pupil; (9) subjects receiving renal replacement therapy at the time of enrollment; (10) subjects who have an impaired ability to ventilate without assistance; (11) subjects who have a history of malignancy or other irreversible disease/conditions with a 6-month mortality > 50%; (12) subjects not fully committed to full support at the time of enrollment; (13) subject receiving inhaled nitric oxide gas prior to enrollment; (14) subject's hospital admission unrelated to covid-19.

(1) patients intubated for more than 72 hours from initiation of the treatment gas; (2) subjects enrolled in another interventional research study; (3) physician of record opposed to enrolling the patient due to perceived safety concerns; or any condition that does not allow the protocol to be followed safely; (4) subjects with past medical history of lung malignancy or pneumonectomy or lung transplant; (5) subjects receiving a tidal volume < 3 cc/kg of ideal body weight at the time of enrollment; (6) subjects with severe burns involving more than 40% of total body surface area; (7) subjects that have experienced cardiac arrest with cpr for longer than 30 minutes; (8) subjects with a presumed severe deficit in cerebral function with fixed dilated pupil; (9) subjects receiving renal replacement therapy at the time of enrollment; (10) subjects who have an impaired ability to ventilate without assistance; (11) subjects who have a history of malignancy or other irreversible disease/conditions with a 6-month mortality > 50%; (12) subjects not fully committed to full support at the time of enrollment; (13) subject receiving inhaled nitric oxide gas prior to enrollment; (14) subject's hospital admission unrelated to covid-19.