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Two hundred twenty-two spinal anesthesias were administered with 10 mg. of tetracaine and 1 ml. of 10 percent dextrose to investigate the effects of vasopressors, patients age, and pH of cerebrospinal fluid on the onset and duration of spinal anesthesia. Neither the differences in overall age, cerebrospinal fluid pH, nor the addition of vasopressors had any significant effect on onset. Duration, however, was significantly prolonged by the addition of vasopressors, 53 percent prolongation by 0.2 mg. of epinephrine and 72 percent prolongation by 2 mg. of phenylephrine.

Diagnosis of amniotic fluid embolism is difficult in a patient under general anesthesia and may initially resemble several other conditions. Successful treatment requires maintenance of adequate cardiac output and oxygenation and prompt heparin treatment of the disseminated intravascular coagulation. The presented case exemplifies another group of patients who are ar risk for amniotic fluid embolism.

The effects of enflurane anesthesia on brainstem auditory evoked responses (BAERs) was determined in 10 patients with normal hearing undergoing various surgical procedures. Arterial blood pressure, body temperature, and arterial Pco2 were controlled during the 2- to 5-hour recording sessions. End-tidal enflurane concentrations were continuously recorded on a chemetron Medspect II mass spectrometer in three subjects. BAERs were obtained by, and recorded on a Nicolet CA 1000, from C2 with reference to A1 or !2, with a 2000 click-averaging for each measurement. Enflurane administered at clinical concentrations (0.5% to 3%) produced a consistent changes in BAER latencies. The waves significantly affected (p less than 0.01) were waves III, IV, and V and interpeak latency I-V. The magnitude of theses changes was related to the concentration of enflurane and was magnified by temporarily decreasing the Paco2. These findings confirm similar data obtained in animals which have shown the same effects at doses that can produce generalized seizure activity. BAER analysis shows that changes predominate at the pons and midbrain levels and affect the brain stem conduction time, which likely reflects the action of enflurane on the activity of the reticular activating system.