Controlled cycles in spontaneous-timed noninvasive ventilation: Incidence and associated factors.

Background: The most-used ventilation mode in home mechanical ventilation (HMV) is spontaneous-timed, designed to be essentially spontaneous with a programmed backup rate.

Research Question: We do not know the real frequency of activation of controlled cycles, nor its associated factors.

Study Design: and Methods: We conducted a single-center cohort study of patients with chronic hypoventilation who were started on HMV. We collected the clinical variables, the ventilator programming parameters and the ventilation efficacy data obtained from the built-in software. We analyzed the percentage of controlled cycles (PCC) and the potentially associated clinical variables.

Results: Overall, the PCC was very high (median 44%), with little change during the HMV adaptation period. Individuals with a higher PCC (captured patients) had a lower respiratory rate with ventilation, a higher level of ventilatory assistance, and were not associated with a specific clinical profile.

Interpretation: Controlled cycles are very common during spontaneous-timed ventilation and depend on the patient's ventilatory pattern and the level of ventilatory assistance.