Contributions to inadequate ventilation of low tidal volume (VT) of <5 ml/kg of predicted body weight (PBW), high VT of >12 ml/kg PBW, low respiratory rate (RR) of <12 breaths/min, high RR of >35 breaths/min, and high end-tidal partial pressure of carbon dioxide (Petco₂) of >55 mmHg during the 24 h of pressure support ventilation (PSV, A) and 24 h of Intellivent (B) in the 14 studied patients. A patient can be in adequate ventilation for low RR and high VT, at the same time that may explain why patient number 11 spent more than 100% of the time in inadequate ventilation with Intellivent. With PSV, inadequate ventilation represented 17.1% [interquartile range, 4.3–39.6] of the total ventilation duration in this mode; with Intellivent, inadequate ventilation represented 3.7% [interquartile range, 1.8–10.1] of the total ventilation duration in this mode.