The Ventilator–Sedation Connection
Critical Care
ICU delirium is one of the most common complications in critically ill patients. It is an acute disturbance in attention and awareness that can fluctuate throughout the day. It is particularly common in patients receiving mechanical ventilation and is associated with longer ICU stays, prolonged mechanical ventilation, and poorer outcomes.
For Respiratory Therapists, delirium is especially relevant because mechanical ventilation, sedation, and delirium are closely connected.
Delirium is usually multifactorial. Common contributors include critical illness, inflammation, hypoxemia, metabolic disturbances, sedative medications, pain, sleep disruption, immobility, infection, and the ICU environment.
It can be hyperactive, with agitation and restlessness, or hypoactive, where the patient appears unusually quiet, sleepy, or withdrawn. Hypoactive delirium can easily be missed.
Regular assessment with validated tools such as CAM-ICU, together with sedation assessment using RASS, is therefore important.
One of the most interesting aspects of ICU delirium is its relationship with mechanical ventilation.
Respiratory failure → Intubation → Sedation → Immobility & sleep disruption → Delirium → Agitation/ventilator asynchrony → More sedation → Prolonged ventilation
This cycle can delay recovery and make ventilator liberation more difficult.
For RTs, this means that delirium should not be viewed as a completely separate problem. A patient’s mental status can directly affect their ability to participate in an SBT, follow commands, protect their airway, and progress toward extubation.
RTs play an important role in breaking this cycle.
1. Sedation & Ventilator Liberation
When clinically appropriate, Spontaneous Awakening Trials (SATs) and Spontaneous Breathing Trials (SBTs) should be coordinated as part of the patient’s liberation strategy.
The goal is not simply to keep the patient comfortable and synchronized with the ventilator. It is to use the lightest effective sedation and assess readiness for liberation as early as possible.
The 2025 PADIS focused update suggests dexmedetomidine over propofol when light sedation and/or reduction of delirium are high priorities in mechanically ventilated adults.
2. Recognizing Changes in Mental Status
During respiratory care, a sudden change in behavior should not automatically be considered “agitation” or “non-compliance.”
Ask:
Early recognition and communication with the ICU team can prevent unnecessary escalation of sedation.
3. Supporting the ABCDEF Approach
Delirium management is part of the ICU Liberation Bundle (ABCDEF):
A – Assess, prevent, and manage pain
B – Both SATs and SBTs
C – Choice of analgesia and sedation
D – Delirium: assess, prevent, and manage
E – Early mobility and exercise
F – Family engagement
For RTs, B is particularly relevant, but respiratory care also contributes to sedation management, delirium recognition, and overall ventilator liberation.
The focus is increasingly shifting from simply treating delirium after it develops toward prevention and early prediction.
Recent research has explored prediction models for sedative-associated delirium in mechanically ventilated patients, aiming to identify high-risk patients earlier.
There is also growing interest in individualized sedation strategies and non-pharmacological interventions such as early mobility and sleep-focused care.
Importantly, the latest PADIS update does not support routine use of antipsychotics simply to shorten delirium duration. This reinforces the importance of addressing modifiable risk factors rather than relying on medication alone.
As RTs, recognizing delirium, supporting light sedation strategies, participating in SAT/SBT, and promoting early ventilator liberation can all contribute to breaking the cycle.
The goal is not just to get the patient off the ventilator — it is to get them off the ventilator awake, oriented, and ready to recover.