Comparison of the in vitro myocardial depressant effects of isoflurane and halothane anesthesia. Isoflurane does not alter airway resistance or dynamic resistance in normal dogs. The three agents do not differ in their ability to decrease bronchospasm. All halogenated agents decrease systemic arterial pressure. Isoflurane produces profound muscle relaxation and enhances the action of tubocurarine, pancuronium and to a lesser extent vecuronium and atracrium.
Halothane produces plasma bromides in proportion to dose and length of exposure.
Bromides appear 2 to 3 days after the beginning of exposure, and their half-life is between 9 and 25 days. Symptoms of metabolic encephalopathy include headache, drowsiness, agitation, delirium, hallucination, lethargy, and coma. Enflurane can be responsible for fluoride-induced renal failure. Halogenated agents cause progressive electroencephalographic changes. At 1 MAC, EEG frequency decreases and voltage increases.