Sigh breaths could be beneficial during which ventilation setting?

• A. Pressure-supported ventilation with tidal volume 4-6 mL/kg
• B. Volume-controlled CMV with VT 8-10
• C. Assist-control ventilation with rate 12
• D. NIPPV with BiPAP

Answer: (A)

Sigh breaths are occasional, larger breaths used to recruit collapsed alveoli and prevent small-airway collapse during ventilation. They work best when the ventilator can provide these bigger breaths without changing the overall ventilation pattern.

Pressure-supported ventilation is ideal for this because the patient initiates breaths and the clinician can augment a breath with higher inspiratory pressure to achieve a larger tidal volume, while keeping the usual lung-protective target for the regular breaths (typically 4–6 mL/kg). An occasional sigh in this mode can improve alveolar recruitment without continuously delivering high volumes.

In volume-controlled, fixed tidal volume ventilation, a sigh would raise the volume on top of a preset target, increasing the risk of volutrauma. In assist-control with a fixed rate, breaths are delivered with a set tidal volume; a sigh would disrupt that balance unless the VT for all breaths were increased, which defeats protection. In noninvasive NIPPV with BiPAP, recruitment is less controlled and sighs aren’t a standard, reliable method for alveolar recruitment.