Which of the following is a contraindication for applying positive end expiratory pressure (PEEP)?

Applying positive end-expiratory pressure (PEEP) is generally aimed at improving oxygenation and enhancing lung expansion by preventing alveolar collapse at the end of expiration. However, it can also lead to increased intrathoracic pressure, which may hinder cardiac output, especially in situations like cardiac arrest.

In the context of cardiac arrest in adults, the application of PEEP can decrease venous return to the heart and lead to further compromise of cardiac output. The physiological implications during cardiac arrest indicate that any increase in intrathoracic pressure may impair the effectiveness of chest compressions and thus negatively affect overall resuscitation efforts.

On the other hand, in the setting of a neonatal cardiac arrest, though the application of PEEP might have different physiological implications and techniques compared to adults, adult cardiac arrest specifically presents a clear contraindication for the use of PEEP due to concerns regarding impaired circulation during resuscitation. Hence, the specific risks associated with cardiac arrest in adults make its presentation as a contraindication for PEEP use particularly relevant.