All of the following are appropriate situations for the use of sigh or deep breaths EXCEPT which?

• A. During CPAP With Spontaneous Breathing
• B. During Lung Recruitment Maneuvers
• C. During Pressure Support Ventilation
• D. During Volume-Controlled Ventilation

Answer: (A)

Sighs or deep breaths are used to recruit collapsed alveoli by delivering a brief, larger-than-usual breath to help reopen airways and improve oxygenation. This recruitment-oriented strategy works best when the ventilator can control or reliably augment the breath.

During CPAP with spontaneous breathing, the patient’s breaths are spontaneous and there is no guaranteed, controlled larger breath delivered by the ventilator. A sigh in this mode would be unpredictable and could cause excessive tidal volumes or instability, so it’s not considered appropriate.

In contrast, lung recruitment maneuvers are specifically designed to open collapsed units, and sighs provide the targeted, periodic deep breaths that support that goal. Pressure Support Ventilation allows the patient to initiate breaths while the machine adds support, so a programmed larger breath (sigh) can be delivered reliably. Volume-Controlled Ventilation also enables a temporary increase in tidal volume to achieve recruitment without relying on patient spontaneity.

So the situation where sighs aren’t appropriate is CPAP with spontaneous breathing, where no controlled or augmented breath is delivered by the ventilator.