Lung Recruitment Maneuvers: How Do They Work?

Respiratory compromise can lead to parts of the lung collapsing, a process known as atelectasis. Collapsed alveoli reduce the surface area available for oxygen exchange and can lead to low oxygen levels. Lung recruitment maneuvers are techniques used by anesthesiologists and critical care clinicians to reopen these closed airways and improve breathing efficiency. Understanding how these maneuvers work elucidates why they are an important tool in modern respiratory care.

When a patient is anesthetized, normal breathing patterns change. Muscles that usually control breathing are impaired, and mechanical ventilation is needed to support air flow. However, it delivers air differently from natural breaths. These changes, combined with lying flat and the pressure of abdominal organs on the diaphragm, can lead to the collapse of small air sacs in the lung ^1,2.

Lung recruitment maneuvers work by temporarily increasing airway pressure to reopen collapsed alveoli. The idea is similar to inflating a balloon: a brief, higher pressure is needed to separate its walls, then a lower pressure can keep it open. Once the alveoli are recruited, positive end-expiratory pressure (PEEP) can prevent them from collapsing again during ventilation ^3–5.

There are several ways to perform these maneuvers. One method is the sustained inflation technique, in which the ventilator delivers a continuous pressure for about 10 to 20 seconds. Another approach is the stepwise increase in PEEP, gradually raising pressure over several breaths until oxygenation improves. Some clinicians use intermittent sigh breaths with larger-than-normal tidal volumes to achieve a similar effect. Determining the method to use depends on the patient’s condition, type of surgery, and equipment available ^6–8.

When recruitment is successful, several positive changes occur. Oxygen levels in the blood rise as more alveoli participate in gas exchange. Lung compliance (or the ability of the lungs to stretch) improves, meaning less pressure is required to deliver each breath. Carbon dioxide removal becomes more efficient, and uneven ventilation between different lung regions decreases. These effects can reduce the risk of postoperative pneumonia and shorten time on the ventilator ^9,10.

Although lung recruitment maneuvers can be beneficial, they are not without risk. High airway pressures may temporarily reduce blood returning to the heart, causing low blood pressure. In fragile lungs, excessive pressure can lead to barotrauma, including pneumothorax. For this reason, recruitment maneuvers must be carefully tailored and continuously monitored. They may be unsuitable for patients with severe emphysema, recent lung surgery, or unstable circulation ^11,12.

Lung recruitment maneuvers are a practical method for reversing anesthesia- and ventilation-related atelectasis. By briefly increasing airway pressure and then maintaining adequate PEEP, clinicians can reopen collapsed alveoli and enhance gas exchange. While not appropriate for every patient, these maneuvers play a valuable role in protecting the lungs and improving outcomes in the operating room and intensive care unit.

References

1. Hedenstierna, G. & Edmark, L. Effects of anesthesia on the respiratory system. Best Practice & Research Clinical Anaesthesiology 29, 273–284 (2015). DOI: 10.1016/j.bpa.2015.08.008

2. openanesthesia. Effects of Anesthesia on the Respiratory System. OpenAnesthesia https://www.openanesthesia.org/keywords/effects-of-anesthesia-on-the-respiratory-system/.

3. Suzumura, E., Amato, M. & Cavalcanti, A. Understanding recruitment maneuvers. Intensive care medicine 42, (2015). DOI: 10.1007/s00134-015-4025-5

4. van der Zee, P. & Gommers, D. Recruitment Maneuvers and Higher PEEP, the So-Called Open Lung Concept, in Patients with ARDS. in Annual Update in Intensive Care and Emergency Medicine 2019 (ed. Vincent, J.-L.) 59–69 (Springer International Publishing, Cham, 2019). DOI: 10.1007/978-3-030-06067-1_5.

5. Pelosi, P., de Abreu, M. G. & Rocco, P. R. New and conventional strategies for lung recruitment in acute respiratory distress syndrome. Crit Care 14, 210 (2010). DOI: 10.1186/cc8851

6. Jauncey-Cooke, J. I., Bogossian, F. & East, C. E. Lung recruitment—A guide for clinicians. Australian Critical Care 22, 155–162 (2009). DOI: 10.1016/j.aucc.2009.06.004

7. Poletto, E. et al. Lung recruitment manoeuvre strategies in paediatric intensive care units across Europe. ERJ Open Research 11, (2025). DOI: 10.1183/23120541.00781-2024

8. Pensier, J. et al. Effect of lung recruitment maneuver on oxygenation, physiological parameters and mortality in acute respiratory distress syndrome patients: a systematic review and meta-analysis. Intensive Care Med 45, 1691–1702 (2019). DOI: 10.1007/s00134-019-05821-9

9. Oh, E. J., Lee, E. J., Heo, B., Huh, J. & Min, J.-J. Physiological benefits of lung recruitment in the semi-lateral position after laparoscopic surgery: a randomized controlled study. Sci Rep 12, 3909 (2022). DOI: 10.1038/s41598-022-04841-8

11. Kidane, B. et al. The Potential Dangers of Recruitment Maneuvers During One Lung Ventilation Surgery. Journal of Surgical Research 234, 178–183 (2019). DOI: 10.1016/j.jss.2018.09.024

12. Guerin, C. et al. Efficacy and safety of recruitment maneuvers in acute respiratory distress syndrome. Ann Intensive Care 1, 9 (2011). DOI: 10.1186/2110-5820-1-9