Sevoflurane (Ultane)

Mask Induction - Non-pungent and minimally airway-irritating compared to other volatile agents, making it the preferred agent for inhalation induction in pediatric patients.

MAC values - MAC is dose-dependent and age-adjusted: children ~2.5%, adults ~1.7–2.0%, elderly ~1.5%. Over-administration is a common error in geriatric cases.

Blood Pressure - Causes dose-dependent reduction in mean arterial pressure via peripheral vasodilation. Monitor closely and be prepared to treat hypotension.

Heart Rate - Minimal direct effect on heart rate — does not cause the tachycardia seen with desflurane. Bradycardia is possible at high doses.

Myocardial Depression - Mild dose-dependent myocardial depression. Use with caution in patients with reduced ejection fraction or significant valvular disease.

Other Effects - Peripheral vasodilation (reducing SVR); mild myocardial depression; bronchodilation via direct airway smooth muscle relaxation

Respiratory Depression - Causes dose-dependent respiratory depression, including reduced tidal volume and increased respiratory rate.

Airway Irritability - Less airway-irritating than isoflurane or desflurane; bronchodilatory properties make it a reasonable choice in patients with reactive airway disease.

Compound A / Nephrotoxicity - Sevoflurane reacts with CO₂ absorbents (soda lime) to form Compound A, a potentially nephrotoxic byproduct. No human data currently links Compound A to acute kidney injury; however, the FDA recommends minimum fresh gas flow of 1 L/min for cases ≤2 MAC-hours, and ≥2 L/min for longer cases. Avoid closed-circuit delivery.

Malignant Hyperthermia - A known triggering agent for malignant hyperthermia. Assess patient and family history prior to administration. Have dantrolene immediately available per institutional protocol.

Uterine Relaxation - Sevoflurane reduces uterine contractility in a dose-dependent manner. At >0.5 MAC, uterine tone is significantly reduced — factor into management during obstetric cases and be prepared to address uterine atony postpartum.

Uterine Atony Risk - Avoid or minimize concentration (≤0.5 MAC) during active labor or uterine surgery due to significant reduction in uterine contractility. Coordinate with obstetric team regarding oxytocin administration.

Placental Transfer - Crosses the placenta; neonatal respiratory depression may occur.

Drug Interactions - Concurrent use of Nitrous Oxide reduces the required MAC of sevoflurane. At 66% N₂O, MAC of sevoflurane decreases approximately 50%. Opioids and benzodiazepines have additive CNS depression; MAC is further reduced.

Absolute - Known or suspected genetic susceptibility to malignant hyperthermia

Relative - Patients with pre-existing renal impairment (Compound A risk at low flow rates); severe hepatic dysfunction

Caution - Patients with reduced cardiac reserve or valvular heart disease (vasodilatory effects); obstetric cases requiring uterine tone; elderly patients (lower MAC requirement)

Enhances inhibitory GABAergic neurotransmission (GABA-A receptor potentiation) and suppresses excitatory NMDA and neuronal nicotinic acetylcholine receptors, leading to loss of consciousness and sensation.

Hepatic (3-5%)

Pulmonary

None