Which ventilator type is described as delivering fixed breaths independent of patient effort?

The ventilator type that delivers fixed breaths independent of patient effort is the time cycled ventilator. This means that the ventilator initiates breaths based solely on a predetermined time interval, regardless of whether the patient is attempting to breathe on their own or not.

In a time cycled mode, breaths are delivered at regular intervals set by the clinician, ensuring consistent ventilation to the patient. This is particularly useful in scenarios where sedation or neuromuscular blockade may diminish the patient's ability to initiate breaths. By providing fixed breaths, the ventilator contributes to the maintenance of adequate minute ventilation and prevents hypoventilation.

In contrast, other types of ventilators, such as pressure cycled and assist mode ventilators, respond to the patient’s efforts or specific pressure thresholds, allowing for spontaneous breathing. Volume cycled ventilators deliver set volumes but can still be influenced by patient effort depending on the mode set. Thus, the defining characteristic of the time cycled ventilator is its ability to deliver breaths autonomously based on time, which addresses specific clinical needs during mechanical ventilation.