Ketamine

Ketamine in the ICU – quick reference

Adult dosing; light background for readability. Use with your fentanyl ± dexmedetomidine plan; avoid large rapid boluses if hypertension is a concern.

Indications (ICU and ED)

• Analgesia Sub-dissociative opioid-sparing pain control in trauma, burns, post-op abdominal pain, opioid tolerance/hyperalgesia, neuropathic pain.
• Sickle crisis Vaso-occlusive crisis pain when opioid-sparing is needed or allodynia limits opioid escalation.
• Procedural sedation Short painful procedures, dressing changes, reductions.
• RSI/induction Especially in hypotensive trauma or with bronchospasm.
• ICU sedation Analgosedation adjunct or alternative to propofol/benzodiazepines.
• Status asthmaticus Bronchodilation and improved ventilation.
• Refractory status epilepticus NMDA antagonism for seizure control.
• Severe agitation Excited delirium rescue with airway-ready monitoring.
• Status migrainosus Rescue in selected protocols.
• Alcohol withdrawal Refractory cases as adjunct to standard care.
• Psychiatry Treatment-resistant depression (protocolized settings).

Dosing cheat sheet

• Analgesia (sub-dissociative): bolus 0.1–0.3 mg/kg IV given slowly; infusion 0.1–0.3 mg/kg/hr (≈1.7–5 mcg/kg/min). Titrate by 0.05–0.1 mg/kg/hr q15–30 min.
• Sickle cell VOC pain: same sub-dissociative dosing; avoid large/rapid boluses if BP/HR sensitive.
• Procedural sedation: 0.5–1 mg/kg IV over 1–2 min, then 0.25–0.5 mg/kg IV q5–10 min PRN. IM 3–5 mg/kg if no IV.
• RSI/induction: 1–2 mg/kg IV once (lower end if shocked/on pressors).
• ICU maintenance sedation: 0.3–1 mg/kg/hr; short-term up to 2 mg/kg/hr with close monitoring.
• Status asthmaticus: 0.5–1 mg/kg IV once, then 0.5–1 mg/kg/hr.
• Refractory status epilepticus: load 1–2 mg/kg IV, then 1–5 mg/kg/hr (protocols up to 10 mg/kg/hr to EEG target).
• Severe agitation/excited delirium: 4–5 mg/kg IM or 1–2 mg/kg IV with airway-ready monitoring.
• Status migrainosus: 0.2–0.3 mg/kg IV once or infusion 0.1–0.3 mg/kg/hr for 3–6 hr.
• Refractory alcohol withdrawal: 0.3 mg/kg IV then 0.3–0.5 mg/kg/hr as adjunct to standard therapy.

Units crosswalk: 0.1 mg/kg/hr ≈ 1.7 mcg/kg/min. Use kg weight and round to practical infusion rates.

Practical pearls and safety

• Hemodynamics: mild–moderate ↑BP/↑HR, most after bolus; prefer slow small boluses or start a low infusion if hypertension is a concern.
• Catecholamine depletion: late sepsis/critical illness can unmask myocardial depression → BP may fall; start low and be ready to support.
• Airway/secretions: hypersalivation common → suction first; consider glycopyrrolate 0.2 mg IV PRN.
• CNS: dysphoria/emergence reactions are dose/rate-related; avoid rapid pushes; tiny GABAergic rescue if needed.
• Gut: generally motility-neutral—useful when ileus risk makes anticholinergics undesirable.
• Combinations: plays well with opioids; dexmedetomidine offsets tachy/HTN and improves sleep continuity.
• Titration: adjust q15–30 min to pain/RASS/BP/HR; continuous ECG/SpO₂; capnography preferred with opioids.
• Renal/hepatic: no renal adjustment; go slow in hepatic impairment/cirrhosis.

Contraindications and cautions

• Absolute: known ketamine or formulation allergy.
• Strong cautions: uncontrolled HTN; acute aortic dissection; active ischemia/severe CAD; tachyarrhythmias; severe pulmonary HTN; ICH/SAH where BP surges are hazardous.
• Neuropsychiatric: severe psychosis/mania—use only if benefits outweigh risks with close monitoring.
• Endocrine: pheochromocytoma or untreated thyrotoxicosis → exaggerated sympathetic response.
• Pregnancy: use only when benefits outweigh risks and after OB consult.
• Peri-MI/HOCM: avoid large boluses; prefer slow titration.

If severe hypertension, chest pain, ischemic ECG changes, or distressing dysphoria occurs, pause and treat; resume at a lower rate or consider an alternative.

Monitoring and hold parameters

• Continuous ECG and pulse oximetry; use capnography when combined with opioids.
• Check BP/HR every 5 min during bolus and every 15 min during titration.
• Hold or reduce for: new chest pain/ischemic ECG, severe uncontrolled HTN, sustained HR above target, intolerable dysphoria, or SpO₂ < 92% despite support.