FiO2 and PEEP Oxygenation Adjustment

Key Points

• Oxygenation issues are primarily addressed by adjusting FiO2 and PEEP.
• Target the lowest FiO2 needed to maintain SpO2 above 92% and pO2 around 80-100 mm Hg.
• FiO2 greater than 50% increases risk of oxygen-related lung injury.

Equipment

• Ventilator with FiO2 and PEEP adjustment controls
• Continuous pulse oximetry and blood pressure monitoring
• ABG workflow access for pO2 reassessment
• Team communication pathway for rapid escalation if instability occurs

Procedure Steps

1. Confirm oxygenation deficit pattern and current ventilator settings.
2. Review current FiO2 and PEEP before making changes.
3. Prioritize lowest effective FiO2 strategy while aiming for SpO2 above 92% and pO2 in normal target range (80-100 mm Hg).
4. Increase FiO2 or PEEP based on clinical response and safety profile.
5. Keep baseline awareness that PEEP is commonly started around 4-6 cm H2O and rarely decreased below that range.
6. Reassess pressure effects after PEEP increases and maintain total pressures below about 35 cm H2O.
7. Monitor for signs of overdistention/barotrauma risk during higher pressure support.
8. Reassess hemodynamics because rising intrathoracic pressure can reduce venous return and lower blood pressure.
9. Repeat ABG/vital reassessment after adjustment and refine settings accordingly.

Common Errors

• Sustaining high FiO2 without reassessment → avoidable oxygen-toxicity risk.
• Increasing PEEP without pressure/hemodynamic monitoring → barotrauma and hypotension risk.
• Ignoring blood pressure decline after PEEP increase → delayed recognition of reduced venous return.
• Treating oxygenation and ventilation goals as interchangeable → ineffective or unsafe parameter changes.

Related

• ventilator-parameter-adjustment-principles - Concept-level framework for choosing oxygenation versus ventilation settings.
• invasive-mechanical-ventilation-modes - Mode selection shapes how FiO2/PEEP changes interact with other parameters.