From the Guidelines
Yes, you can use Positive End-Expiratory Pressure (PEEP) with a Laryngeal Mask Airway (LMA), but with important limitations, as second-generation LMAs have been shown to enable the use of PEEP, although the effectiveness depends on the device and the patient's condition 1. The use of PEEP with an LMA can be beneficial in certain situations, such as improved oxygenation in patients with reduced lung compliance, prevention of atelectasis, and increased functional residual capacity, which can be beneficial for obese patients or those with respiratory conditions. Some of the key advantages of using PEEP with an LMA include:
- Improved oxygenation
- Prevention of atelectasis
- Increased functional residual capacity However, there are significant disadvantages to consider, including:
- Risk of gastric insufflation and potential aspiration
- Air leaks around the LMA cuff, reducing effective ventilation
- Potential for airway trauma from increased cuff pressures
- Increased likelihood of LMA displacement The most recent and highest quality study on this topic is from 2019, which recommends individualized PEEP to improve oxygenation, end-expiratory lung volume, and respiratory system mechanics during ventilation 1. When using PEEP with an LMA, it's essential to:
- Monitor for adequate seal
- Watch for signs of gastric insufflation
- Be prepared to convert to an endotracheal tube if ventilation becomes inadequate or if the patient is at high risk for aspiration. In terms of the specific level of PEEP that can be safely applied, the evidence suggests that PEEP can typically be applied safely up to 10 cmH2O with most modern LMAs, though this depends on having a good seal 1. Overall, the use of PEEP with an LMA requires careful consideration of the potential benefits and risks, and should be individualized to the patient's specific condition and needs.
From the Research
Using PEEP with an LMA
- PEEP can be used with a laryngeal mask airway (LMA), but its effectiveness and potential benefits vary depending on the study and context 2, 3.
- A study from 2010 found that applying a PEEP of +7 cm H₂O with a LMA under spontaneous ventilation did not improve oxygen saturation in healthy patients 2.
- In contrast, a 2022 study found that using a PEEP of 8 mbar with a ProSeal LMA mask during positive pressure ventilation slightly improved gas exchange and compliance, but did not increase overall gas leakage 3.
Advantages of using PEEP with an LMA
- Improved gas exchange: A study in pediatric patients found that using PEEP with a ProSeal LMA improved gas exchange during positive pressure ventilation 4.
- Increased lung volume: PEEP can increase the lung volume available for gas exchange, which may be beneficial in certain situations 2.
- Potential to reduce atelectasis: PEEP may help to prevent atelectasis, which is a well-described mechanism that impairs gas exchange during general anesthesia 2.
Disadvantages of using PEEP with an LMA
- Risk of gas leakage: Applying PEEP with a LMA may increase the risk of gas leakage, although this was not found to be significant in all studies 3.
- Need for reseating: Using PEEP with a LMA may require more frequent reseating of the device, as found in a 2022 study 3.
- Limited benefit: Some studies have found that using PEEP with a LMA does not provide significant benefits in terms of oxygen saturation or gas exchange 2, 3.