Structure
Basic Information
MAC: 1.21
MAC-BAR: 1.8
MAC-Awake: 0.5
Metabolism %: 0.21
Vapor Pressure: 2381
Age related MAC Values1
| Age | MAC | MAC + 70%Nâ‚‚O |
|---|---|---|
| 26 ± 4 | 1.28% | 0.56% |
| 44 ± 7 | 1.15% | 0.5% |
| 64 ± 5 | 1.05% | 0.37% |
How MAC affects HR
| Agent | MAC value that ↑ HR |
|---|---|
| Sevoflurane | 1.5 |
| Isoflurane | 0.5 |
| Desflurane | 1.0 |
Additional Info
- MH Trigger
- Pungent
- Heart rate increases appear to be related to airway irritation and catecholamine release.2 This can be attenuated by the administration of opioids or beta blockade.
- Sinoatrial node discharge rate is slowed and conduction in the His-Purkinje system is prolonged (prolonged QT interval
- ↑ RR, bronchodilation
- ↓ TV, MV
Coronary stealis a myth.3- Dose dependent depression of the ventilatory response to hypercarbia and hypoxia
- ↓ ciliary movement and altered mucus characteristics
- Dose dependent effect on skeletal muscle relaxation
- Potentiates the action of neuromuscular blockers (greatest with myasthenia gravis)
- In the presence of a dessicated COâ‚‚ absorber exothermic reaction with volatile anesthetics can lead to fire and/or carbon monoxide formation.
- Minimal metabolism. Metabolized into flouride ions with can be nephrotoxic although it has not been shown to be clinically significant in patients without kidney disease.1
- All MAC values can be decreased by co-administered agents (benzodiasepines, opioids, α₂ agonists, etc.)
Tanaka S, Tsuchida H, Nakabayashi K, Seki S, Namiki A. The effects of sevoflurane, isoflurane, halothane, and enflurane on hemodynamic responses during an inhaled induction of anesthesia via a mask in humans. Anesth Analg. 1996 Apr;82(4):821-6. doi: 10.1097/00000539-199604000-00025. PMID: 8615504. ↩︎
Crystal GJ. Isoflurane and the Coronary Steal Controversy of the 1980s: Origin, Resolution, and Legacy. J Anesth Hist. 2017 Apr;3(2):56-62. doi: 10.1016/j.janh.2017.04.002. Epub 2017 Apr 12. PMID: 28641827. ↩︎