Which of the following is not a method to prevent or treat perioperative atelectasis?

The method that is not used to prevent or treat perioperative atelectasis is related to the approach of using anesthesia to relax the diaphragm. While muscle relaxation is a critical component of general anesthesia to facilitate surgical procedures, it does not specifically address the management or prevention of atelectasis.

In contrast, the other options focus on maintaining lung volume and improving ventilation:

Continuous positive airway pressure (CPAP) ventilation involves delivering a steady stream of airway pressure, which can help keep the alveoli open during mechanical ventilation, thereby preventing atelectasis.

Recruitment maneuvers are techniques performed during mechanical ventilation that involve temporarily increasing airway pressure to reopen collapsed alveoli. This can restore lung volume and enhance oxygenation.

The open-lung concept advocates for maintaining lung recruitment during mechanical ventilation and preventing derecruitment, which directly supports lung inflation and mitigates the risk of atelectasis.

Thus, the option that does not serve as a method to prevent or treat perioperative atelectasis is the use of anesthesia aimed at relaxing the diaphragm, as it does not contribute to lung protection and management.