ABSTRACT
BACKGROUND: The extraction of the middle latency auditory evoked potentials (MLAEP) is usually done by moving time averaging (MTA) over many sweeps (often 250-1,000), which could produce a delay of more than 1 min. This problem was addressed by applying an autoregressive model with exogenous input (ARX) that enables extraction of the auditory evoked potentials (AEP) within 15 sweeps. The objective of this study was to show that an AEP could be extracted faster by ARX than by MTA and with the same reliability. METHODS: The MTA and ARX methods were compared with the Modified Observer's Assessment of Alertness and Sedation Scale (MOAAS) in 15 patients scheduled for cardiac surgery and anesthetized with propofol. The peak amplitudes and latencies were recorded continuously for the MTA- and ARX-extracted AEP. An index, AAI, was derived from the ARX-extracted AEP as well. RESULTS: The best predictors of the awake and anesthetized states, in terms of the prediction probability, Pk, were the AAI (Pk [SE] = 0.93 [0.01]) and Na-Pa amplitude (MTA, Pk [SE] = 0.89 [0.02]; ARX, Pk [SE] = 0.87[0.02]). When comparing the AAI at the MOAAS levels 5-3 versus 2-0, significant differences were achieved. During the transitions from awake to asleep, the ARX-extracted AEP were obtained with significantly less delay than the MTA-extracted AEP (28.4 s vs. 6 s). CONCLUSION: The authors conclude that the MLAEP peaks and the AAI correlate well to the MOAAS, whether extracted by MTA or ARX, but the ARX method produced a significantly shorter delay than the MTA.
Subject(s)
Anesthetics, Intravenous/pharmacology , Evoked Potentials, Auditory/drug effects , Propofol/pharmacology , Humans , Predictive Value of Tests , Time FactorsABSTRACT
Una vez implantado el Programa de Control de Calidad Asistencial en el Hospital de la Santa Creu i Sant Pau y tras seis años de funcionamiento, se plantea como segundo paso trasladar el modelo general a los propios servicios clínicos, en un intento de realizar una autoevaluación directa por los facultativos. Se describe la metodología utilizada en algunos Servicios (Anestesiología-Reanimación, Medicina Intensiva, Otorrinolaringología) y algunos de los resultados más relevantes. Se concluye que el control de calidad en los servicios clínicos, aunque de implementación lenta y difícil, es un buen sistema para asegurar una práctica correcta de la totalidad de los miembros del Servicio