M16Analgesia, sedation, prophylaxis and critical-care nutrition

Clinical overview

Comfort, wakefulness, mobility, thrombosis prevention and nutrition are active organ-support treatments. Deep unreviewed sedation prolongs ventilation, obscures neurological change and increases weakness/delirium. Indiscriminate acid suppression and anticoagulation create bleeding/infection harm. Early full-calorie feeding can overfeed the acute stress response, while prolonged underfeeding worsens catabolism and recovery. Every supportive prescription needs an indication and daily review.

Pregnancy and postpartum care add placental transfer, fetal effects, neonatal sedation/withdrawal, lactation, neuraxial analgesia, haemorrhage, hypertensive disease and the physical/psychological consequences of birth. Maternal indication remains central. Use the least harmful effective medicine, but do not leave a ventilated or injured patient in pain because she is pregnant.

Core knowledge

Analgesia before sedation

Pain causes sympathetic activation, sleep disruption, splinting and delirium. Assess it with a self-report scale when possible; use a validated behavioural tool in patients unable to communicate. Identify the source—incision, uterine contraction, line, immobility, neuropathy, abdomen, breast or headache—and treat it directly.

Use multimodal analgesia. Paracetamol is a common baseline agent when liver function and total dose allow. Opioids are titrated to pain and physiology, with attention to hypotension, ileus, respiratory depression, accumulation in kidney/liver failure and neonatal/breastfeeding exposure. NSAID use depends on gestation, renal function, bleeding, hypertension and postpartum context; avoid casual antenatal administration, especially later pregnancy, and follow national obstetric guidance. Neuraxial/regional techniques can reduce systemic exposure but require anticoagulation, infection, platelet/coagulation and haemodynamic review.

Ketamine can provide analgesia/sedation with relative preservation of respiratory drive, but sympathetic and psychological effects and raised pressure states matter. Neuropathic agents, local anaesthetic techniques and non-pharmacological comfort measures are adjuncts, not universal prescriptions.

Sedation target and agent

Write a target depth and indication. Most ventilated patients should be kept as lightly sedated and interactive as safely possible, with deeper sedation reserved for severe ARDS/dyssynchrony, neuromuscular blockade, raised intracranial pressure, status epilepticus, dangerous agitation or a procedure. Reassess the target after every major change.

Propofol allows rapid titration but can cause hypotension, hypertriglyceridaemia and, with high/prolonged exposure, propofol infusion syndrome. Dexmedetomidine can facilitate light/cooperative sedation but may cause bradycardia and hypotension. SCCM’s 2025 focused update conditionally favours dexmedetomidine over propofol when light sedation and delirium reduction are leading priorities in mechanically ventilated adults; this is general adult evidence, not a universal pregnancy rule. Benzodiazepines are important for seizure, alcohol/benzodiazepine withdrawal and selected anxiety but can accumulate and contribute to delirium.

Typical adult infusion ranges: propofol 25–50 µg/kg/min (higher rates and long duration raise propofol-infusion-syndrome risk), dexmedetomidine 1 µg/kg over 10 minutes then 0.2–0.7 µg/kg/hour, ketamine 15–30 µg/kg/min, fentanyl 1–2 µg/kg/hour, morphine 0.1 mg/kg/dose titrated to effect, and paracetamol 15–20 mg/kg/dose (commonly 1 g four-hourly in an adult) as the multimodal baseline. Confirm against your unit's card and adjust for organ function.

Consider placental transfer before delivery and infant exposure during lactation, but distinguish a single emergency/procedural dose from prolonged infusion. Pharmacy, anaesthesia and neonatal teams should advise when prolonged high-dose exposure is anticipated. Maternal ventilation and humane analgesia are not withheld.

Delirium, sleep and mobilisation

Delirium is acute fluctuating disturbance of attention/cognition and may be hyperactive, hypoactive or mixed. Screen with a validated ICU tool after arousal permits; hypoactive delirium is easily missed. Search for pain, hypoxia/hypercapnia, sepsis, stroke/eclampsia, glucose/electrolyte disorder, urinary retention, withdrawal, sleep disruption and medicines.