Which statement correctly describes when Assist-Control mode is preferred?

• A. AC is preferred for weaning toward spontaneous breathing
• B. AC provides only spontaneous breaths
• C. Assist-Control mode provides full support with a set tidal volume for every breath, including patient-triggered breaths
• D. AC is never used in neonates

Answer: (B)

Assist-Control mode provides full ventilatory support by delivering a preset tidal volume on every breath, whether the infant triggers the breath or the machine delivers it. Because each inspiration delivers the same volume, you’re guaranteed consistent minute ventilation even if the infant’s respiratory drive is immature or irregular. This makes it a good choice when reliable support is needed to prevent hypoventilation, such as in neonates with apnea risk or unstable respiratory effort. It’s not limited to spontaneous breaths; patient-triggered breaths are still given a full breath with the set volume, which distinguishes it from modes that progressively decrease support as the patient once breathes more independently. For weaning toward spontaneous breathing, other approaches like SIMV or PSV/CPAP are typically preferred because they encourage handling more breaths on your own rather than continuing full-volume support. So the mode is about providing consistent, full-volume breaths for all inspirations, rather than only spontaneous breathing or never being used in neonates.