Inhalational Anesthetic Agents

Enflurane, CFClH-CF2-O-CF2H

enflurane

Introduced in 1972.

Physical Properties

  • vapor pressure = 175 mmHg at 20 deg C
  • halogenated ether
  • mild, sweet,ethereal oder

Organ System Effects

Cardiovascular
  • negative cardiac inotrope
  • lowers cardiac output, arterial blood pressure, myocardial oxygen consumption
  • heart rate usual increases
Respiratory
  • rapid, shallow breathing with increased paCO2
  • abolishes hypoxic drive
  • bronchodilator
  • depresses mucocillary function
  • marked respiratory depression so that at 1 MAC, paCO2 = 60 mmHg
CNS
  • general anesthesia, MAC = 1.7
  • increases CBF and ICP
  • increases CSF secretion
  • deep enflurane aneshthesia -> EEG spike-and-wave pattern -> tonic-clonic seizures, exacerbated by hypocapnia (so hyperventilation not recommended)
  • decreases CMRO2 (unless seizures occur)

Biotransformation and Toxicity

  • fluoride is produced but even after 10 MAC-hours average concentrations are < 40 micromols/L
  • causing mild reduction in renal concentrating ability

Contraindications/Precautions

  • malignant hyperthermia susceptibility
  • preexisting kidney disease
  • seizure disorder
  • intracranial hypertension
  • isoniazid enhances enflurane defluorination




Send Comments to Greg Gordon MD, gjg@po.cwru.edu
Department of Anesthesiology
The MetroHealth System
2500 MetroHealth Drive
Cleveland, Ohio 44109-1998
Phone: (216) 778-4801
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