Sevoflurane should be administered only by persons trained in the administration of general anesthesia. Facilities for maintenance of a patent airway, artificial ventilation and oxygen enrichment and circulatory resuscitation must be immediately available.
The concentration of sevoflurane being delivered from a vaporizer must be known exactly. As volatile anesthetics differ in their physical properties, only vaporizers specifically calibrated for sevoflurane should be used. The administration of general anesthesia must be individualized based on the patient's response. Hypotension and respiratory depression increase as anesthesia is deepened.
Isolated reports of QT prolongation, very rarely associated with Torsade de pointes (in exceptional cases, fatal), have been received. Caution should be exercised when administering sevoflurane to susceptible patients.
Isolated cases of ventricular arrhythmia were reported in pediatric patients with Pompe's disease.
Caution should be exercised when administering general anesthesia, including sevoflurane to patients with mitochondrial disorders.
Hepatic: Very rare case of mild, moderate and severe postoperative hepatic dysfunction or hepatitis with or without jaundice have been reported in post-marketing experiences.
Clinical judgment should be exercised when sevoflurane is used in patients with underlying hepatic conditions or under treatment with drugs known to cause hepatic dysfunction (see Adverse Reactions).
It has been reported that previous exposure to halogenated hydrocarbon anesthetics, especially if the interval is <3 months, may increase the potential to hepatic injury.
Malignant Hyperthermia: In susceptible individuals, potent inhalation anesthetic agents, including sevoflurane, may trigger a skeletal muscle hypermetabolic state leading to high oxygen demand and the clinical syndrome known as malignant hyperthermia. The clinical syndrome is signaled by hypercapnia and may include muscle rigidity, tachycardia, tachypnea, cyanosis, arrhythmias and/or unstable blood pressure. Some of these nonspecific signs may also appear during light anesthesia, acute hypoxia, hypercapnia and hypovolemia.
In clinical trials, 1 case of malignant hyperthermia was reported.
In addition, there have been post-marketing reports of malignant hyperthermia. Some of these have been fatal.
Treatment of malignant hyperthermia includes discontinuation of triggering agents (eg, sevoflurane), administration of IV dantrolene sodium and application of supportive therapy (consult prescribing information of IV dantrolene sodium for additional information on patient management), and application of support therapy. Such therapy includes vigorous efforts to restore body temperature to normal, respiratory and circulatory support as indicated, and management of electrolyte-fluid-acid-base abnormalities. Renal failure may appear later and urine flow should be monitored and sustained if possible.
Preoperative Hyperkalemia: Use of inhaled anesthetic agents has been associated with rare increases in serum potassium levels that have resulted in cardiac arrhythmias and death in pediatric patients during the postoperative period. Patients with latent as well as overt neuromuscular disease, particularly Duchenne muscular dystrophy, appear to be most vulnerable. Concomitant use of succinylcholine has been associated with most, but not all, of these cases. These patients also experienced significant elevations in serum creatinine kinase levels and in some cases, changes in urine consistent with myoglobinuria. Despite the similarity in presentation to malignant hyperthermia, none of these patients exhibited signs or symptoms of muscle rigidity or hypermetabolic state. Early and aggressive intervention to treat the hyperkalemia and resistant arrhythmias is recommended, as is subsequent evaluation for latent neuromuscular disease.
General: During maintenance of anesthesia, increasing the concentration of sevoflurane produces dose-dependent decreases in blood pressure. Excessive decrease in blood pressure may be related to depth of anesthesia and in such instances may be corrected by decreasing the inspired concentration of sevoflurane.
As with all anesthetics, maintenance of hemodynamic stability is important to the avoidance of myocardial ischemia in patients with coronary artery disease.
The recovery from general anesthesia should be assessed carefully before patients are discharged from the post-anesthesia care unit.
Although recovery of consciousness following sevoflurane administration generally occurs within minutes, the impact on intellectual function for 2 or 3 days following anesthesia has not been studied. As with other anesthetics, small changes in moods may persist for several days following administration (see Effects on the Ability to Drive and Use Machines).
Replacement of Desiccated CO2 Absorbents: Rare cases of extreme heat smoke; and/or spontaneous fire in the anesthesia machine have been reported during sevoflurane use in conjunction with the use of desiccated CO2 absorbent, specifically those containing potassium hydroxide. An unusually delayed rise or unexpected decline of inspired sevoflurane concentration compared to the vaporizer setting may be associated with excessive heating of the CO2 absorbent canister.
An exothermic reaction, enhanced sevoflurane degradation and production of degradation products (see Description) can occur when the CO2 absorbent becomes desiccated such as, after an extended period of dry gas flow through the CO2 absorbent canisters. Sevoflurane degradants (methanol, formaldehyde, carbon monoxide and Compounds A, B, C and D) were observed in the respiratory circuit of an experimental anesthesia machine using desiccated CO2 absorbents and maximum sevoflurane concentrations (8%) for extended periods of time (≥2 hrs). Concentrations of formaldehyde observed at the anesthesia respiratory circuit (using sodium hydroxide containing absorbents) were consistent with levels known to cause mild respiratory irritation. The clinical relevance of the degradants observed under this extreme experimental model is unknown.
When a clinician suspects that the CO2 absorbent may be desiccated, it should be replaced before administration of sevoflurane. The color indicator of most CO2 absorbents does not necessarily change as a result of desiccation. Therefore, the lack of significant color change should not be taken as an assurance of adequate hydration. Carbon dioxide absorbents should be replaced routinely, regardless of the state of the color indicator.
Renal Impairment: Because of the small number of patients with renal insufficiency (baseline serum creatinine >1.5 mg/dL) studied, the safety of sevoflurane administration in this group has not yet been fully established. Therefore, sevoflurane should be used with caution in patients with renal insufficiency.
Neurosurgery: In patients at risk for elevations of ICP, sevoflurane should be administered cautiously in conjunction with ICP-reducing maneuvers eg, hyperventilation.
Seizures: Rare cases of seizures were reported in association with sevoflurane (see Pediatric Use as follows and Adverse Reactions).
Drug Abuse and Dependence: None known.
Effects on Ability to Drive and Use Machines: Patients should be advised that performance of activities requiring mental alertness, such as, operating a motor vehicle or hazardous machinery, may be impaired for some time after general anesthesia.
Use in pregnancy & lactation: Pregnancy Category B: Reproduction studies in rats and rabbits at doses up to 1 MAC have revealed no evidence of impaired fertility or harm to the fetus due to sevoflurane. There are no adequate and well-controlled studies in pregnant women; therefore, sevoflurane should be used during pregnancy only if clearly needed.
Labor and Delivery: In a clinical trial, the safety of sevoflurane was demonstrated for mothers and infants when used for anesthesia during cesarean section. The safety of sevoflurane in labor and vaginal delivery has not been demonstrated.
Sevoflurane, like, other inhalational agents, has relaxant effect on the uterus with the potential risk of uterine bleeding. Clinical judgment should be observed when using sevoflurane during obstetric anesthesia.
It is not known whether sevoflurane or its metabolites is excreted in human milk. Due to the absence of documented experience, women should be advised to skip breastfeeding for 48 hrs after administration of sevoflurane and discard milk produce during this period.