The investigators hypothesize that it is feasible and safe to deliver a conservative approach to oxygen therapy in mechanically ventilated critically ill patients (a tiem frame of, on average,10 days).

1. Identify patients likely to require ventilation until the day after tomorrow (a time frame of 36 hours of average)
2. Deliver a conservative oxygen therapy protocol while in ICU (a time frame on average of 10 days)
3. Target an oxygen saturation between 90 and 92%
4. Adjust FiO2 to achieve target SaO2 at all times
5. Assess percentage of time patient is within target
6. Assess for safety of this approach

Inclusion Criteria:

• Mechanical ventilation
• expected to be ventilated until the day after tomorrow (a tiem frame of, on average 48 hours)

Exclusion Criteria:

• expected to be off mechanical ventilation today or tomorrow
• carbon monoxide poisoning
• necrotizing fasciitis