The effects of isoflurane and desflurane titrated to a bispectral index of 60 on the cortical somatosensory evoked potential during pediatric scoliosis surgery.

In this study, we compared the effect of isoflurane and desflurane on the posterior tibial somatosensory evoked potential recorded by scalp electrodes during correction of idiopathic scoliosis in pediatric patients. Depth of sedation was controlled by maintaining bispectral index (BIS) at 60 throughout the study. Comparison of patients breathing desflurane and isoflurane showed an evoked cortical amplitude (N37-P45) of 0.53 +/- 0.3 microV versus 1.3 +/- 0.8 microV (P = 0.014), respectively. In addition to this comparison, a crossover design was included whereby the desflurane or isoflurane received in the first part of the study was changed to the other anesthetic. Substituting one anesthetic for another confirmed our initial finding that the cortical evoked amplitude is greater with isoflurane than with desflurane. No differential effect was found between desflurane and isoflurane on the evoked subcortical (N31-P34) amplitude or the P37 latency.

Characterization of incident stroke signs and symptoms: findings from the atherosclerosis risk in communities study.

BACKGROUND AND PURPOSE: Although patterns of stroke occurrence and mortality have been well studied, few epidemiological data are available regarding the clinical characteristics of stroke events. METHODS: We evaluated hospitalized stroke events reported in the Atherosclerosis Risk in Communities (ARIC) Study to describe the clinical characteristics of incident stroke. Confirmed stroke cases (n=474) were evaluated for stroke symptoms (headache, vertigo, gait disturbance, convulsions) and stroke signs (hemianopia, diplopia, speech deficits, paresis, paresthesia/sensory deficits) and their univariate associations with race, sex, and stroke subtype. RESULTS: Over 9.2 years of follow-up, 402 (85%) ischemic and 72 (15%) hemorrhagic strokes occurred. Frequency of stroke symptoms (95% CIs) were as follows: headache (27.4%; 23.4% to 31.4%), gait disturbance (10.8%; 7.9% to 13.6%), convulsions (4.4%; 2.6% to 6.3%), and vertigo (2.1%; 0.8% to 3.4%). Speech deficits occurred in 24.0% (20.2% to 27.9%), hemianopia in 14.6% (11.4% to 17.7%), and diplopia in 5.5% (3.4% to 7.5%) of cases. Most cases involved paresis (81.6%; 78.1% to 85.1%), while fewer cases experienced sensory deficits (44.5%; 40.0% to 49.0%). Blacks were more likely than whites to experience paresis (85.4% versus 78.2%; P=0.044). Men were more likely than women to experience a gait disturbance (14.4% versus 6.7%; P=0.007). Persons with hemorrhagic strokes had a higher proportion of headaches (55.6% versus 22.4%; P=0.001) and convulsions (11.1% versus 3.2%; P=0.003) than those with ischemic events, while speech and sensory deficits were more common in ischemic strokes (26.1% versus 12.5%, P=0.013, and 49.0% versus 19.4%, P=0.001, respectively). CONCLUSIONS: We present epidemiological data concerning the clinical characteristics of incident stroke in a population-based cohort. Although minor differences by race, sex, and stroke subtype were observed, data from additional follow-up are required to confirm observed variations.