Guide — Critical Care
Sedation, Analgesia & Delirium in the ICU
The era of deeply sedated, paralyzed ventilator patients is over. The modern approach treats pain first, keeps sedation light, avoids benzodiazepines, and screens for delirium — all wrapped in the ABCDEF bundle. This guide covers the PADIS framework and where the RT fits into it.
9 min read · Critical Care
Written by Apex Respiratory Editorial Team
Educational use only. This material supports respiratory therapy education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional protocols, or physician orders. Always follow facility policies and current provider orders, and verify calculations independently before clinical use.
Overview
Sedation and analgesia in the ICU are no longer about keeping the patient asleep. The Society of Critical Care Medicine’s PADIS guidelines — Pain, Agitation/Sedation, Delirium, Immobility, and Sleep — reframed the goal around comfort, light sedation, and avoiding the harms of over-sedation: prolonged ventilation, delirium, and weakness.
Three principles anchor the approach. Analgesia first— treat pain before adding a sedative, because much agitation is actually pain. Target light sedation— lighter sedation shortens ventilation and improves outcomes unless a specific indication calls for deep sedation. And prefer non-benzodiazepine sedatives — propofol or dexmedetomidine over benzodiazepines, which are linked to more delirium.
Key Concepts
A short list of agents and a set of validated bedside scales carry most of the practice. The analgesics are the opioids — fentanyl, hydromorphone, and morphine. The sedatives are propofol, dexmedetomidine, and the benzodiazepines midazolam and lorazepam, which the guidelines steer away from. The scales below standardize how depth of sedation and delirium are measured.
| Tool | Purpose | Range |
|---|---|---|
| RASS (Richmond Agitation-Sedation Scale) | Depth of sedation / agitation | +4 to −5, target 0 to −2 |
| SAS (Riker Sedation-Agitation Scale) | Alternative sedation scale | 1 to 7 |
| CAM-ICU | Delirium screen | Positive / negative |
| ICDSC | Delirium screen | 0–8 |
The ABCDEF bundle packages these pieces into a daily routine. Its centerpiece is the SAT + SBT pairing— “wake up and breathe” — in which the daily sedation interruption is coordinated with the spontaneous breathing trial so weaning readiness is assessed while the patient is awake.
| Letter | Element | Note |
|---|---|---|
| A | Assess, prevent, and manage pain | Analgesia first — treat pain before adding a sedative |
| B | Both SAT and SBT | Pair the spontaneous awakening trial with the breathing trial — “wake up and breathe” |
| C | Choice of analgesia and sedation | Prefer propofol or dexmedetomidine over benzodiazepines |
| D | Delirium: assess, prevent, and manage | Screen with CAM-ICU or ICDSC; reduce benzodiazepines |
| E | Early mobility and exercise | Mobilize as soon as it is safe to do so |
| F | Family engagement and empowerment | Involve family in reorientation and care |
Assessment & Findings
- Score depth with the RASS. The Richmond Agitation-Sedation Scale runs from +4 (combative) to −5 (unarousable), with 0 to −2 the usual target. Document it routinely so titration is driven by a number, not an impression.
- The SAS is an alternative. The Riker Sedation-Agitation Scale grades from 1 (unarousable) to 7 (dangerous agitation) and is interchangeable with the RASS where a unit uses it instead.
- Screen for delirium. The CAM-ICU returns a positive or negative result and the ICDSC scores 0–8. Both detect delirium that is otherwise easy to miss — especially the quiet, hypoactive form.
- Hypoactive delirium is the common one. Hyperactive delirium is obvious; hypoactive delirium — withdrawn, flat, slow — is more common and routinely missed without active screening.
- Assess pain first. Before escalating sedation for agitation, evaluate for pain. A patient fighting the ventilator is often a patient in pain, not one who needs to be more deeply sedated.
RT Priorities / Interventions
- Coordinate the SBT with the SAT. The breathing trial is the RT’s, the awakening trial is the nurse’s — run them together so the patient is assessed for weaning while sedation is lifted, not hours apart.
- Assess weaning readiness during lightened sedation. A lighter RASS is the window to evaluate spontaneous effort and readiness to extubate — run the rapid shallow breathing index once the patient is awake enough to participate.
- Recognize that over-sedation prolongs ventilation. A deeply sedated patient cannot demonstrate readiness to wean. Flag the over-sedated patient and advocate for lightening so the weaning assessment can actually happen.
- Provide capnography during procedural sedation. Continuous end-tidal CO₂ monitoring detects hypoventilation and apnea before the SpO₂ falls, an important safeguard during procedural sedation.
Common Pitfalls
- Deep sedation by default. Reaching for deep sedation as the routine setting, rather than titrating to the lightest level that keeps the patient safe, prolongs ventilation and ICU stay.
- Benzodiazepine-heavy regimens. Leaning on midazolam or lorazepam drives delirium and longer ventilation. Prefer propofol or dexmedetomidine unless there is a specific benzodiazepine indication.
- Not coordinating the SAT with the SBT. Running the awakening and breathing trials separately wastes the awake window. Pair them so the breathing trial happens while the patient is roused.
- Under-treating pain. Treating agitation that is really pain with more sedative leaves the pain unaddressed and the patient over-sedated. Assess pain first.
- Over-sedation masking the neuro exam. Deep sedation hides the neurologic picture, making it impossible to follow mental status — a real problem in the head-injured or encephalopathic patient.
Board Exam Pearls
- Know the RASS range cold: +4 to −5, with a target of 0 to −2 for most ventilated patients.
- Analgesia first — treat pain before adding a sedative, because agitation is often pain.
- Light sedation improves outcomes and shortens ventilation versus deep sedation.
- Avoid benzodiazepines when possible — prefer propofol or dexmedetomidine, which cause less delirium.
- Know the ABCDEF bundle and that the SAT is paired with the SBT — “wake up and breathe.”
- The CAM-ICU is the bedside delirium screen.
FAQ
What is the target RASS for most ventilated patients?
For most mechanically ventilated patients the target is light sedation, a RASS of 0 to −2 — awake or only lightly sedated, easily roused to voice. Light sedation is associated with shorter duration of ventilation and better outcomes than deep sedation. Deeper targets are reserved for specific indications such as severe ARDS requiring neuromuscular blockade, refractory intracranial hypertension, or status epilepticus.
Why are benzodiazepines avoided for ICU sedation?
Benzodiazepines such as midazolam and lorazepam are associated with more delirium and longer duration of mechanical ventilation than non-benzodiazepine alternatives. The PADIS guidelines suggest using propofol or dexmedetomidine over a benzodiazepine for sedation in critically ill ventilated adults. Benzodiazepines are reserved for specific indications — alcohol or sedative withdrawal, seizures, and deep sedation when truly required.
What does analgesia-first (analgosedation) mean?
Analgesia-first, or analgosedation, means treating pain before reaching for a sedative. Much of what looks like agitation in a ventilated patient is untreated pain from the endotracheal tube, suctioning, lines, and immobility. Establishing adequate analgesia first — often with an opioid such as fentanyl — frequently reduces or removes the need for a separate sedative and supports the goal of keeping sedation light.
What is the SAT/SBT pairing?
The spontaneous awakening trial (SAT) is a daily interruption of sedation; the spontaneous breathing trial (SBT) is a trial of minimal ventilator support to assess readiness to extubate. Pairing them — the “wake up and breathe” protocol — means the nurse-led SAT is coordinated with the RT-led SBT so the patient is assessed for breathing while sedation is lightened. The paired strategy shortens ventilation and improves outcomes compared with doing either alone.
Put it to work
Once sedation is lightened and the patient is participating, the next question is whether they are ready to come off the ventilator. Run the rate and tidal volume through the calculator to get the rapid shallow breathing index.
Open the RSBI Calculator →Related Resources
Sources
- Devlin JW, Skrobik Y, Gélinas C, et al. Clinical practice guidelines for the prevention and management of pain, agitation/sedation, delirium, immobility, and sleep disruption in adult patients in the ICU (PADIS). Crit Care Med. 2018;46(9):e825-e873.
- Kacmarek RM, Stoller JK, Heuer AJ. Egan's Fundamentals of Respiratory Care. 12th ed. Elsevier; 2021.