From the Guidelines
To troubleshoot low oxygen saturation on a mechanical ventilator, increase FiO2 to 1.0 and adjust ventilator settings to ensure adequate chest rise and prevent auto-triggering, while also assessing the need to adjust positive end-expiratory pressure level and ensuring endotracheal tube/tracheostomy and ventilator circuit continuity. When investigating the cause of hypoxemia, consider the following steps:
- Check the ventilator circuit for disconnections, kinks, or water accumulation, and ensure the endotracheal tube is properly positioned, as recommended by the American Heart Association in collaboration with other medical societies 1.
- Assess for secretions by performing endotracheal suctioning using a closed suction system with sterile technique.
- Evaluate ventilator settings by adjusting the respiratory rate to 10 breaths/min for adults, 20 to 30 breaths/min for infants and children, and 30 breaths/min for neonates, and limiting pressure or tidal volume to generate adequate chest rise, typically 4–6 mL/kg ideal body weight for adults and neonates, and 5–8 mL/kg for children 1.
- Adjust the trigger settings to prevent the ventilator from auto-triggering with chest compressions and possibly prevent hyperventilation and air trapping.
- Assess the need to adjust the positive end-expiratory pressure level to balance lung volumes and venous return, and ensure endotracheal tube/tracheostomy and ventilator circuit continuity to prevent unplanned airway dislodgement or tubing disconnections 1.
- Consider patient positioning, such as prone positioning or at minimum a 30-degree head elevation, to improve oxygenation.
- Check for pneumothorax, pulmonary edema, atelectasis, or pneumonia through physical examination and chest imaging, and perform arterial blood gas analysis to determine if the hypoxemia is accompanied by hypercapnia or acidosis.
From the Research
Troubleshooting Low Oxygen Saturation on a Mechanical Ventilator
To troubleshoot low oxygen saturation (hypoxemia) on a mechanical ventilator, consider the following steps:
- Check the patient's airway, breathing, and circulation (ABCs) to ensure that the airway is patent and that the patient is receiving adequate ventilation 2
- Verify that the ventilator settings are appropriate for the patient's condition, including the fraction of inspired oxygen (FIO2), positive end-expiratory pressure (PEEP), and tidal volume 3, 4, 5, 6
- Consider adjusting the PEEP and FIO2 settings to optimize oxygenation, as high PEEP can help recruit collapsed alveoli and improve oxygenation, while high FIO2 can help increase oxygen delivery to the lungs 3, 4
- Monitor the patient's arterial blood gases and pulmonary mechanics to assess the effectiveness of the ventilator settings and make adjustments as needed 5, 6
- Consider using a lung-protective ventilation strategy, which aims to avoid barotrauma, volutrauma, atelectotrauma, and oxygen toxicity, to promote lung recovery and improve oxygenation 2
Ventilator Settings
When adjusting ventilator settings to troubleshoot low oxygen saturation, consider the following:
- Increasing PEEP can help improve oxygenation by recruiting collapsed alveoli, but may also increase the risk of barotrauma and other adverse effects 3, 5, 6
- Increasing FIO2 can help increase oxygen delivery to the lungs, but may also increase the risk of oxygen toxicity 3, 4
- Adjusting tidal volume and inspiratory-to-expiratory ratio can also affect oxygenation and should be considered when troubleshooting low oxygen saturation 4, 5, 6
Monitoring and Assessment
To effectively troubleshoot low oxygen saturation on a mechanical ventilator, it is essential to:
- Continuously monitor the patient's oxygen saturation and arterial blood gases to assess the effectiveness of the ventilator settings 3, 4, 5, 6, 2
- Assess the patient's pulmonary mechanics, including lung compliance and resistance, to identify potential issues with ventilation 5, 6
- Consider using additional monitoring tools, such as transpulmonary pressure monitoring, to optimize ventilator settings and promote lung recovery 2