Can volatile anesthetics (inhalation anesthetics) be used?

Can Volatile Anesthetics Be Used?

Yes, volatile anesthetics can be used safely and effectively for general anesthesia in most clinical settings, with specific considerations for patient selection and monitoring. 1

Primary Recommendations for Use

Noncardiac Surgery

• It is beneficial to use volatile anesthetic agents during noncardiac surgery for maintenance of general anesthesia in hemodynamically stable patients at risk for myocardial ischemia (Class IIa recommendation, Level B evidence). 1
• The choice of anesthetic technique is best left to the discretion of the anesthesia care team, as no study has clearly demonstrated outcome changes from specific agent selection. 1

Cardiac Surgery

• Volatile anesthetics may be considered for maintenance of anesthesia during cardiopulmonary bypass (CPB), though this is a weaker recommendation (Class IIb, Level B evidence). 1
• The landmark 2019 MYRIAD trial demonstrated no significant difference in 1-year mortality between volatile anesthetics and total intravenous anesthesia (TIVA) in patients undergoing coronary artery bypass grafting (2.8% vs 3.0%, P=0.71). 2
• Multiple randomized trials in cardiac surgery have shown no consistent differences in ischemia, myocardial infarction, or death between volatile agents and high-dose opioid or propofol-based techniques. 1

Absolute Contraindications

Do not use volatile anesthetics in the following situations:

• Known or suspected susceptibility to malignant hyperthermia, including patients with RYR1 or CACNA1S genetic variants. 3
• Patients with absolute contraindications to volatile agents based on known sensitivity to halogenated anesthetics. 3

Critical Safety Considerations

Malignant Hyperthermia Risk

• Volatile anesthetics can trigger malignant hyperthermia in susceptible individuals, particularly when combined with succinylcholine. 3
• Early recognition is essential: watch for hyperthermia, muscle rigidity, tachycardia, hypercapnia, and metabolic acidosis. 3
• If suspected, immediately discontinue the volatile agent, administer dantrolene, and provide supportive care. 3

Renal Considerations with Sevoflurane

• Sevoflurane exposure should not exceed 2 MAC·hours at fresh gas flow rates of 1 to <2 L/min to minimize Compound A exposure. 3
• Fresh gas flow rates <1 L/min are not recommended with sevoflurane. 3
• Safety in patients with renal insufficiency (creatinine >1.5 mg/dL) has not been established. 3
• Sevoflurane may cause glycosuria and proteinuria with prolonged procedures at low flow rates. 3

Cardiovascular Effects

• QT prolongation with potential for torsade de pointes has been reported; exercise caution in patients with congenital Long QT Syndrome or those taking QT-prolonging medications. 3
• Monitor for respiratory depression, which may be augmented by opioid premedication. 3

Pediatric Hyperkalemia Risk

• Volatile anesthetics have been associated with rare but severe perioperative hyperkalemia in pediatric patients, particularly those with latent neuromuscular disease (especially Duchenne muscular dystrophy). 3
• Risk is increased with concomitant succinylcholine use. 3

Situations Where Volatile Anesthetics Should NOT Be Used

ICU Procedural Pain Management

• Strong recommendation against using inhaled volatile anesthetics for procedural pain management in critically ill adults (strong recommendation, very low quality evidence). 1
• This is due to increased resource requirements, safety concerns outside the operating room, and very limited evidence of benefit. 1

Environmental Considerations

• Nitrous oxide should not be used when choosing an inhalational anesthetic due to its significant greenhouse gas properties. 4
• Sevoflurane is preferred over desflurane or isoflurane for environmental reasons when an inhalational agent is required. 4
• Nitrous oxide administration immediately before and after CPB is not recommended. 1

Technical Considerations for Safe Use

CO₂ Absorbent Interactions

• KOH-containing CO₂ absorbents (e.g., Baralyme) are not recommended for use with sevoflurane due to enhanced degradation. 3
• Degradation is increased with desiccated absorbents, high sevoflurane concentrations, low fresh gas flows, and increased absorbent temperature. 3
• Use fresh absorbents and avoid desiccation to minimize degradant formation. 3

Monitoring Requirements

• Oxygenator exhaust concentrations of volatile anesthetic agents should be monitored during CPB (Class IIa recommendation). 1
• Use only approved equipment for delivering volatile anesthetics during CPB. 1
• Monitor depth of anesthesia with end-tidal anesthetic concentration to reduce consumption. 4

Low Flow Techniques

• Low fresh gas flow techniques should be employed when using inhaled anesthetics to reduce environmental impact. 4
• Balance environmental concerns with safety limits, particularly the <1 L/min restriction for sevoflurane. 3

Clinical Equivalence Considerations

• The scientific foundation for clinically relevant cardioprotection by volatile anesthetics is weak in contemporary practice. 5
• TIVA can be performed safely in patients undergoing cardiac surgery with equivalent outcomes. 5, 2
• In noncardiac surgery, one randomized trial found no significant reduction in postoperative troponin I release with sevoflurane versus propofol (p=0.4). 6
• When equal clinical benefit is expected, clinicians may choose between volatile agents and TIVA, recognizing different environmental impacts. 4

Immunologic Effects

• Volatile anesthetics have predominantly immunosuppressive effects on both innate and adaptive immunity. 1
• Immunosuppression may be detrimental for cancer patients but potentially beneficial for septic patients; consider this when planning anesthesia for oncologic surgery. 1
• Volatile anesthetics can provide organ protection (heart, kidney, liver, brain) through anti-inflammatory and cytoprotective mechanisms when dose and exposure time are optimized. 1