Influence of general anesthesia on otoacustic emissions

Aim of our study was the evaluation of the effects of Remifentanil-Propofol during surgical operations in general anaesthesia on external acustic cells. In 50 patients, with normal acustic function, hospitalized for tonsillectomy, evoked otoacustic emissions transient (TEOAE) and distorsion products-Gram (DP-gram) were measured. We divided patient random in two groups (group A and group B). In the group A general anesthesia was induced by Propofol (2.5 mg/kg), Mivacurio (0.2 mg/Kg). Isoflurano (0.5%), nitrous oxide (N2O) in 40% oxigen (O2) while in group B general anesthesia was induced by Remifentanil TCI (Stanpump Stanford University, Palo Alto, CA) 5 ng/ml and Propofol. TCI (Diprifusor ®) 4 ug/ml in air/oxigen ventilation. The results in the group A shown a reduction of intensity and reproducibility of the TEOAE during general anesthesia induced by N2O while in the group B any alterations statistically relevant of the TEOAE and DP-gram were recorded. The total absence of modifications TEOAE and DP-Gram during general anaesthesia induced by Remifentanil-Propofol, is guarantee by an action more natural on physiological omeostasis.