DOSAGE & ADMINISTRATION
The concentration of enflurane being delivered from a vaporizer during anesthesia should be known.
This may be accomplished by using:1) vaporizers calibrated specifically for enflurane;
2) vaporizers from which delivered flows can be calculated.
Preanesthetic Medication
Preanesthetic medication should be selected according to the need of the individual patient, taking into account that secretions are weakly stimulated by enflurane and that enflurane does not alter heart rate. The use of anticholinergic drugs is a matter of choice.
Surgical Anesthesia
Induction may be achieved using enflurane alone with oxygen or in combination with oxygen-nitrous oxide mixtures. Under these conditions some excitement may be
encountered. If excitement is to be avoided, a hypnotic dose of a short-acting barbiturate should be used to induce unconsciousness, followed by the enflurane mixture. In general, inspired concentrations of 2.0 to 4.5% enflurane produced surgical anesthesia in 7 to 10 minutes.
Maintenance
Surgical levels of anesthesia may be maintained with 0.5 to 3% enflurane Maintenance concentrations should not exceed 3%. If added relaxation is required supplemental doses of muscle relaxants may be used. Ventilation to maintain the tension of carbon dioxide in arterial blood in the 35 to 45 mm Hg range is preferred. Hyperventilation should be avoided in order to minimize possibleCNS excitation
The level of blood pressure during maintenance is an inverse function of enflurane concentration in
the absence of other complicating problems. Excessive decreases (unless related to hypovolemia) may be due to depth of anesthesia and in such instances should be corrected by lightening the level of anesthesia.
Analgesia
Enflurane 0.25 to 1% provides analgesia for vaginal delivery equal to that produced by 30 to 60% nitrous oxide These concentrations normally do not produce amnesia. See also the information on the effects of enflurane on uterine contraction contained in the CLINICAL PHARMOCOLOGY
Cesarean Section
Enflurane should ordinarily be administered in the concentration range of 0.5 to 1% tosupplement other general anesthetics. See also the information on the effects ofenflurane on uterine contraction contained in the CLINICAL PHARMACOLOGY section
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