Desflurane (Suprane)

MAC Value - 6% in 100% O2 (age-adjusted). Significantly reduced with nitrous oxide, opioids, and increasing patient age. Use end-tidal monitoring to titrate.

Rapid Emergence - The main reason to choose desflurane. Blood:gas partition coefficient of 0.42 means it washes in and out faster than isoflurane or sevoflurane — great for long cases where you want a quick, predictable wake-up.

Airway Irritability - Highly pungent. Never use for inhalation induction — you'll get coughing, breath-holding, laryngospasm, and potentially bronchospasm. Use only for maintenance in an already-secured airway.

Sympathetic Stimulation - Rapidly increasing the concentration (especially above 1 MAC) can trigger a significant sympathetic response — tachycardia and hypertension. Titrate slowly and avoid big jumps in concentration. Treat with opioids, beta-blockers, or backing off the vaporizer.

Malignant Hyperthermia - Like all volatile agents, desflurane triggers MH in susceptible patients. Screen history carefully and have dantrolene available.

Increased ICP - Causes dose-dependent cerebral vasodilation. Avoid or use very low concentrations in patients with elevated ICP or traumatic brain injury (TBI). Pair with hyperventilation if used at all in neurosurgical cases.

Environmental Impact - Desflurane has a global warming potential roughly 20x that of sevoflurane and ~2,500x that of CO2. Many institutions have restricted or eliminated its use on sustainability grounds. Withdrawn from the US market by the manufacturer in 2022, though may still be available in some settings.

Drug Interactions - Potentiates neuromuscular blockade — reduce NMB doses and monitor TOF. Additive CNS and respiratory depression with opioids, benzos, and propofol. Sympathomimetic interaction with epinephrine (arrhythmia risk, though less than halothane).

Pediatric Implications - Not recommended for pediatric use. Very high rate of emergence agitation and airway complications in children. Sevoflurane is strongly preferred in this population.

Obstetric Implications - Crosses the placenta and causes dose-dependent uterine relaxation. Rapid offset can be an advantage for maternal recovery, but neonatal depression is possible at higher concentrations. Not commonly used for obstetric anesthesia given airway concerns and environmental considerations.

Absolute:

Known or suspected MH susceptibility

Known hypersensitivity to halogenated agents

Inhalation induction (any patient)

Pediatric patients

Relative:

Elevated ICP or TBI

Reactive airway disease / asthma

Severe coronary artery disease (risk of tachycardia and hemodynamic swings)

Caution:

Elderly patients (MAC significantly reduced, more sensitive to hemodynamic effects)

Patients at high risk for PONV

Hypovolemia

Potentiates GABA-A receptor activity and inhibits NMDA receptors, suppressing neuronal excitability. Also modulates potassium and sodium channels. Like other volatiles, exact mechanism of anesthetic action is not fully characterized.

Hepatic (minimal, ~0.02% — least metabolized of the volatile anesthetics)

Pulmonary (>99% exhaled unchanged)

Requires a heated, pressurized vaporizer (Tec 6) — cannot be used in standard variable-bypass vaporizers due to its high vapor pressure and low boiling point (23.5°C)

Voluntarily withdrawn from the US market by Baxter in 2022 due to environmental concerns; may still be available outside the US

Lowest hepatic metabolism of any volatile agent — potentially advantageous in severe hepatic impairment, though clinical significance is debated