Comparison of anesthetic agents on otoacoustic emissions in children: propofol vs ketamine.

BACKGROUND: Otoacoustic emission (OAE) tests are important evaluation tools for diagnosis of peripheral auditory pathology. Sedation or general anesthesia may be required for the performance of the OAE tests. The aim of this retrospective study was to compare the effects of anesthetic agents, propofol and ketamine, on OAEs in children. METHODS: Fifty healthy children who underwent tonsillectomy and/or adenoidectomy under general anesthesia were included in this study. Three anesthesia induction protocols were defined for this study and the anesthesiologist applied his or her own choice. Transient evoked otoacoustic emissions (TEOAEs) and distortion-product otoacoustic emissions (DPOAEs) were automatically recorded in both ears of each patient prior to anesthetic (predrug) and following the loss of consciousness 5 min later (postdrug) by an audiologist blinded to the method of anesthesia. Acceptable TEOAEs were defined as signal noise ratio (S/N) of above 3 dB SPL (decibel sound pressure level) and DPOAEs of 6 dB SPL or above. Between-group and within-group comparisons and correlations were performed for statistical analysis. RESULTS: Retrospective review of the anesthesia charts from 44 cases that completed the study showed that propofol, ketamine, and sevoflurane induction protocols were used in 21, 18, and 5 cases, respectively. Measurements of 36 ears in the propofol group and 34 ears in the ketamine group were included in the final analysis. Postdrug TEOAE and DPOAE amplitudes were significantly lower than predrug amplitudes except at 8 kHz in the ketamine group. There was no significant statistical difference in postdrug DPOAE measurements between propofol and ketamine groups but a significant difference was observed at 2 and 3 kHz of postdrug TEOAE measurements. TEOAE measurements were below 3 dB in 8 of 34 ears after ketamine and in 1 of 36 ears after propofol administration. There was a significant difference between the groups with respect to the incidence of successful measurements of TEOAEs. The DPOAE measurements were affected less by these drugs. CONCLUSION: DPOAE measurements were reduced similarly by propofol and ketamine anesthesia. Lower false outcome ratio in TEOAE measurements made propofol a better option than ketamine.

Effects of sevoflurane and desflurane on otoacoustic emissions in humans.

Otoacoustic emissions (OAEs) are non-invasive, easy to apply and objective test methods which are widely used to determine the presence of hearing in audiology clinics. Under certain circumstances, the study should be applied under general anesthesia. The aim of this study was to determine the influence of new short-acting inhalation agents, desflurane and sevoflurane, on OAE in humans. These short-acting agents are widely used in general anesthesia. Thirty-one healthy patients who underwent septoplasty and turbinoplasty surgery were included in this study. Unpremedicated patients were anesthetized and monitored by a standard protocol except the inhalation agents. Desflurane and sevoflurane were added to the inhaled gas mixture at ~1MAC, 5-6 % and 1.5-2 %, respectively. Transient evoked otoacoustic emissions and distortion product otoacoustic emissions measured in both ears of each patient preoperatively in the operating room before induction, 5 min after induction, after the completion of surgical procedure while the anesthetic agents are still given and 1 h after surgery in the ward. Between-group and within-group comparisons and correlations with hemodynamic parameters were performed for statistical analysis. The measurements of 26 ears in desflurane group and 28 ears in sevoflurane group were evaluated. There were no differences in initial measurements between groups (p > 0.05). Both groups presented significant decrease in intraoperative measurements and changes in time were statistically significant (p < 0.05). The changes in OAEs were similar to changes in systemic blood pressures. Correlation between OAEs and systemic blood pressures were significant (p < 0.05). In conclusion, sevoflurane and desflurane decreased OAEs around 2-3 dB; OAEs are still measurable under inhalation agents. This provides some findings about the OAE status of patient, but the evaluations should be done with the impact of anesthetic agents in mind.

The effect of lidocaine, bupivacaine and ropivacaine in nasal packs on pain and hemorrhage after septoplasty.

We aimed to investigate the effects of local anesthetics soaked in Merocel nasal packs on hemorrhage and pain after septoplasty. The methodology includes a prospective double-blind study that was conducted in patients undergoing septoplasty because of nasal septal deviation. The study included 143 patients. The patients were divided into four groups. Each group received 1% lidocaine + 0.000625% adrenalin, 0.375% ropivacaine, 0.25% bupivacaine as study groups or 0.9% sodium chloride as a control group in their Merocel packs postoperatively. The local anesthetics or sodium chloride were reapplied at the eighth postoperative hour. Each patient was given a questionnaire where verbal analog score and amount of postoperative hemorrhage was noted. The statistical analysis was performed using two sided t test on each patient group at each time point. The results included the patients in the control group needing rescue drug most often. There was no statistically significant difference between bupivacaine and lidocaine plus adrenalin in the patients who requested rescue drug. The patients in the ropivacaine group requested rescue drug more frequently than the bupivacaine and lidocaine plus adrenalin groups. Bupivacaine group had significantly better pain scores versus control group at all intervals except for the first postoperative hour.The bupivacaine group had better pain scores versus ropivacaine and lidocaine plus adrenalin groups in the 4th, 8th and the 24th hours. The bupivacaine group had better pain scores versus lidocaine plus adrenalin in the 12th, 16th and the 20th hours. The ropivacaine group had significantly better pain scores versus control group in the 8th, 12th, 16th, 20th and 24th postoperative hours. The ropivacaine group scored better than lidocaine plus adrenalin group just in the 16th hour. The lidocaine plus adrenalin group had significantly better pain scores versus control group in 4th and 12th hours. There was no statistically significant difference between the study groups in terms of postoperative hemorrhage. We concluded that bupivacaine use in nasal surgery provides better analgesia at least in the first 8 h period and does not cause more bleeding. Topical bupivacaine application to nasal packs should be considered after septoplasty.