Strategy to Avoid Excessive Oxygen Using an Autonomous Oxygen Titration Intervention

Inclusion Criteria: * Age 18 years or older * Hospitalized or will be hospitalized from Emergency Department for major trauma, burn, acute care surgery, or acute respiratory illness * Able to be randomized within 36 hours of hospital arrival * Receiving supplemental oxygen 1-10 liters per minute for documented or presumed hypoxemia (must be higher than baseline for those on chronic oxygen therapy) * Signed and dated informed consent from patient or legally authorized representative (LAR) Exclusion Criteria: * Anticipated hospital discharge within 24 hours * Imminent plans to discontinue supplemental oxygen * Imminent plans to administer high flow nasal oxygen, non-invasive ventilation, or invasive mechanical ventilation * Clinical team unwilling or unable to follow the prescribed oxygen titration method in either randomized group * Known prisoner * Known pregnancy * Known contraindicated conditions for use of the PRO100 device: carbon monoxide poisoning, incapable of handling airway secretions, increased methemoglobin, cyanide poisoning, cluster headaches, undrained pneumothorax, sickle cell crisis, paraquat poisoning or a history of bleomycin poisoning, patients for whom the SpO2 signal is not stable