The clinical value of chloral hydrate in the routine electroencephalogram

Purpose: To evaluate the diagnostic yield and clinical impact of chloral hydrate (CH) in the routine EEG. Methods: The EEG results and records of all patients receiving CH during routine EEG (CH-EEG) at Mayo Clinic Rochester between 4/1/07 and 9/30/07 (n = 216 total; 148 adults) were reviewed for clinical indication, presence of epileptiform abnormalities and EEG duration. The results were compared to an equivalent number of consecutive EEGs performed without CH over the same time period (non-CH-EEGs). The clinical impact of the CH-EEG findings was evaluated by evaluating resulting clinical decisions made in the medical record. Chi-squared analysis was performed for discontinuous data, Student's t-test for continuous data. Results: The proportion of EEGs with sleep-specific epileptiform abnormalities (SSEAs) was not statistically different (7.8% CH-EEG vs. 10.5% non-CH-EEG, p = 0.34). CH was ordered more often by non-epileptologists than epileptologists (57% vs. 35%, p = 0.0004). The mean acquisition time was greater for CH-EEGs (66.9 min vs. 55.1 min; p ≪ 0.001). CH-EEGs resulted in a change in clinical management in 5/216 (2.3%). Discussion: Compared to non-CH-EEGs, CH-EEGs were no more likely to show SSEAs, prolonged the acquisition time, and were associated with changes in clinical care in <3%. Routine use of CH in outpatient EEG is not strongly supported by these data.