# Sedation and Analgesia in the ICU

> Sedation and analgesia in the ICU for NEET-PG Medicine: propofol, midazolam, dexmedetomidine, opioids, RASS targets and propofol infusion syndrome.

- Canonical URL: https://prepelephant.com/topics/neet-pg/medicine/sedation-and-analgesia-in-icu
- Exam / course: NEET-PG · Subject: Medicine
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-14
- Last updated: 2026-10-14
- Reference basis: Oxford Textbook of Critical Care; PADIS Guidelines for adult ICU patients
- How to cite: "Sedation and Analgesia in the ICU", PrepElephant, https://prepelephant.com/topics/neet-pg/medicine/sedation-and-analgesia-in-icu

## Direct answer

Sedation and analgesia in the ICU keep ventilated and critically ill patients comfortable and safe without over-sedating them. Analgesia is started first, usually with an opioid such as fentanyl, and sedation is titrated to a light target on the Richmond Agitation-Sedation Scale, most often 0 to minus 2. Propofol is the classic short-acting agent, while dexmedetomidine gives arousable sedation with less respiratory depression.

## What you must remember

- **Analgesia first:** opioids such as fentanyl come before sedatives, because untreated pain drives agitation, delirium and ventilator dyssynchrony.
- **Propofol:** a short-acting GABA-A potentiator with rapid offset, but it commonly causes hypotension.
- **Propofol infusion syndrome:** metabolic acidosis, rhabdomyolysis, hyperkalaemia, arrhythmia and renal failure after high doses for prolonged periods, so creatine kinase and triglycerides are monitored.
- **Midazolam:** its active metabolite accumulates, so it is avoided for prolonged sedation in favour of propofol or dexmedetomidine.
- **Dexmedetomidine:** an alpha-2 agonist giving cooperative, arousable sedation, limited by bradycardia and hypotension.
- **Opioids in renal failure:** fentanyl is preferred over morphine, whose active metabolites accumulate.
- **Scales:** the Richmond Agitation-Sedation Scale runs from +4 to minus 5, while CPOT or BPS assess pain in intubated patients who cannot report it.
- **Daily interruption:** lightening or stopping sedation each day shortened ventilation in classic trials, though the benefit is smaller when a light-sedation protocol is already used.

## Sedating a ventilated patient with ARDS

A 45-year-old man is intubated for pneumonia with ARDS and is agitated and fighting the ventilator. The team must choose the analgesic, the sedative, the target and the monitoring plan.

1. **Treat pain first:** Start an opioid and reassess pain with CPOT or BPS before adding any sedative.
2. **Set a light target:** Aim for a RASS of 0 to minus 2 in most patients, which permits cooperation and shortens the ventilator course.
3. **Choose the agent:** Propofol is titrated for rapid offset, dexmedetomidine suits patients at risk of delirium, and midazolam is avoided for prolonged sedation.
4. **Monitor for complications:** Check triglycerides, creatine kinase, lactate and potassium on propofol, and watch heart rate on dexmedetomidine.
5. **Interrupt sedation daily:** Lighten or stop sedation each day when it is safe, then retitrate to the target.
6. **Screen for delirium:** Use the CAM-ICU tool, because sedatives can mask or worsen delirium.

## Where the exam tries to catch you

NEET-PG stems often reward the choice that is safest over the long run, not the one that works fastest.

- **Trap:** deep sedation chosen for comfort as the default. **Correct:** light sedation with a RASS target near 0 to minus 2 is preferred, because deep sedation prolongs ventilation.
- **Trap:** propofol continued indefinitely without checking lipids or enzymes. **Correct:** prolonged high-dose propofol risks propofol infusion syndrome, so dose must be reduced and the patient monitored.
- **Trap:** midazolam picked for long-term sedation because it is familiar. **Correct:** its active metabolite accumulates, so propofol or dexmedetomidine is preferred for prolonged use.

## Frequently asked questions

### What is propofol infusion syndrome?

Propofol infusion syndrome is a rare but potentially fatal complication of prolonged high-dose propofol infusion. It causes metabolic acidosis, rhabdomyolysis, hyperkalaemia, arrhythmias and renal failure, and it is prevented by limiting dose and duration and monitoring enzymes and lipids.

### Which sedative is preferred for long-term sedation in ventilated ICU patients?

Propofol or dexmedetomidine is preferred for long-term sedation in ventilated ICU patients rather than midazolam. The active metabolite of midazolam accumulates and prolongs sedation, which delays weaning from the ventilator.

### Why is fentanyl preferred over morphine in renal failure?

Fentanyl is preferred over morphine in renal failure because morphine's active metabolites, especially morphine-6-glucuronide, accumulate as kidney function falls. Fentanyl is cleared hepatically and does not build up active metabolites in the same way.

### What does the Richmond Agitation-Sedation Scale measure?

The Richmond Agitation-Sedation Scale grades sedation depth from +4 for combative to minus 5 for unarousable, with 0 meaning alert and calm. It is used to set and monitor the sedation target in ventilated ICU patients.

### Which scale assesses pain in intubated ICU patients who cannot self-report?

The Critical-Care Pain Observation Tool and the Behavioural Pain Scale assess pain in intubated ICU patients who cannot self-report. Both rely on facial expression, limb movement and ventilator tolerance rather than the patient's own words.