Effects of desflurane on middle ear pressure

Acute Intraoperative Tympanic Membrane Rupture in Patient Anesthetized With Desflurane Without Nitrous Oxide: A Case Report

We report a case of acute intraoperative tympanic membrane (TM) rupture in a patient anesthetized with desflurane without N2O. The patient was undergoing endoscopic retrograde cholangiopancreatography (ERCP) to treat ascending cholangitis. TM rupture is known to occur with N2O but has not been reported in the literature with the use of inhaled volatile anesthetics without N2O. We suspect that several factors contributed to this complication, including prone positioning, a remote history of ear trauma, and the selection of desflurane as the maintenance anesthetic as opposed to a vapor with a higher blood-gas partition coefficient.

Effects of General Anaesthesia on the Middle Ear Pressure

OBJECTIVE

Inhalation agents can have different effects on the middle ear pressure (MEP). We aimed to investigate the effect of sevoflurane and desflurane, the agents used in patients who do not have any ear pathology and who undergo surgery under general anaesthesia, on MEP.

METHODS

Fifty adult patients who were scheduled to undergo inguinal hernia and lower extremity surgery were included in our study. All patients were aged between 20 and 60 years and belonged to the American Society of Anesthesiologists (ASA) I-III class. Patients were divided into two groups, according to the inhalation agent administered for the surgery: sevofluran, Group S (n=25); and desfluran, Group D (n=25). Anaesthetic agents, intraoperative end tidal carbon dioxide and airway pressures were recorded. The MEP was measured for both ears preoperatively, at the intraoperative 5th, 10th, 15th minutes, and at the postoperative 10th and 30th minutes.

RESULTS

The MEP at the intraoperative 10th minute was significantly higher in Group D compared to Group S. In Group D, the MEP increased significantly at the intraoperative 10th and 15th minutes, and postoperative 30th minute, compared to preoperative values. In Group S, the MEP increased significantly at the postoperative 10th minute, compared to preoperative values.

CONCLUSION

We found that desflurane increases the MEP during the intraoperative and postoperative period, compared to sevoflurane.

Effects of Total Intravenous Anesthesia and Low- and High-Flow Anesthesia Implementation on Middle Ear Pressure

Background

The middle ear is an air-filled lacuna in the temporal bone. Inhaled anesthetic agents increase the pressure of this lacuna. Therefore, attention must be paid in choosing not only anesthetic agents but also anesthetic method.

Aim

This study compared the effects of high-flow total intravenous anesthesia (TIVA) and low- and high-flow desflurane anesthesia on middle ear pressure.

Study Design

Randomized prospective double-blind study.

Methods

In this retrospective double-blind study, 90 patients (20–65 years old) scheduled to undergo elective thyroidectomies were divided into three randomized anesthesia groups: high-flow desflurane (Group I), low-flow desflurane (Group II), and high-flow TIVA (propofol, remifentanil) (Group III). The hemodynamic and respiratory parameters and tympanometry were measured before induction (T1), 10 minutes after intubation (T2), 10 minutes before the end of the operation (T3), and 5 (T4), 10 (T5), 15 (T6), and 30 (T7) minutes after the operation.

Results

No statistically significant differences were found in the age, gender, weight, height, body mass index, surgery duration, and anesthetic duration (p > 0.05). There were no statistically significant differences at T1, T3, T4, T5, T6, and T7 (p > 0.007), but there was a significant difference at T2 (p < 0.001), with Groups II and III having lower pressure than Group I (p < 0.001).

Conclusion

The high-flow desflurane group had higher postinduction middle ear pressure values. Therefore, low-flow anesthesia and TIVA can be used more safely in middle ear surgeries, provided that a well-equipped anesthetic device and appropriate monitoring conditions are available.

Effects of steep Trendelenburg position and pneumoperitoneum on middleear pressure in patients undergoing robotic radical prostatectomy

BACKGROUND/AIM

The aim of this study was to quantify the changes in middle ear pressure (MEP) during robot-assisted radical prostatectomy (RARP).

MATERIALS AND METHODS

Thirty patients undergoing RARP were included in this study. MEP was obtained at the following time points: awake (T1), postintubation (T2), pneumoperitoneum + 1 h of Trendelenburg position (T3), pneumoperitoneum + 2 h of Trendelenburg position (T4), pneumoperitoneum + 3 h of Trendelenburg position (T5), desufflation + supine position (T6), and 1 h after extubation in the postanesthesia care unit (T7). Heart rate, mean arterial pressure (MAP), peak airway pressure (PAP), tidal volume, minute ventilation, EtCO₂, and blood gas values were recorded.

RESULTS

MEP was significantly higher at T4, T5, T6, and T7 as compared to T1 values. PAP values were significantly increased at T3, T4, and T5 compared to T2. MAP values at T3, T4, and T5 were significantly higher compared to T1. PaCO₂ increased significantly at T4, T5, and T6 and pH decreased significantly at T4 and T5 when compared to T2.

CONCLUSION

The combination of steep Trendelenburg position and pneumoperitoneum during RARP caused a significant increase in MEP, PaCO₂, and EtCO₂ levels. This propensity for increased MEP may cause problems in patients with preexisting ear disease.

Comparison of the effects of desflurane and sevoflurane on middle ear pressure: a randomized controlled clinical trial

OBJECTIVE

The aim of the present study was to compare the effects of two inhalation anesthetics, desflurane and sevoflurane, on middle ear pressure.

METHODS

After we obtained written consent from the patients and the approval from our institutional ethical committee, we included 56 ASA I-II patients aged between 18 and 60 years in this study. They were randomly divided into two groups of 28 patients each. Desflurane 4-6% (Group D) or sevoflurane 1-2% (Group S) were used for anesthesia management in patients. Baseline tympanometry was carried out and recorded before the induction of anesthesia on both ears, and 3 more measurements were done and recorded 5, 15 and 30 min after induction.

RESULTS

In both groups, middle ear pressure values were found to be significantly elevated when compared to baseline measurements (p < 0.05). When middle ear pressure was compared between the groups, no difference was found between the values obtained at baseline and at 5 min in Group S, while especially the values obtained at 15 min revealed significantly higher middle ear pressures in Group D.

CONCLUSION

It was observed that the increase in middle ear pressure caused by sevoflurane was significantly lower than that caused by desflurane.

Effects of isoflurane on auditory evoked potentials in the cochlea and brainstem of guinea pigs

Electrophysiological recordings of the auditory system are commonly performed in deeply anesthetized animals. This study evaluated the effects of various concentrations of the volatile anesthetic isoflurane (1-3%) on the compound action potential (CAP), cochlear microphonic (CM) and auditory brainstem response (ABR). Recordings were initiated in the awake, lightly restrained animal. Anesthesia was induced with a single dose of Hypnorm (fentanyl and fluanisone). After tracheostomy increasing isoflurane concentrations were applied in N(2)O/O(2) via controlled ventilation. Data were compared to recordings in the awake animal using repeated measures ANOVA and Dunnett's post hoc test. On average, isoflurane dose-dependently suppressed the amplitude and increased the latency of the CAP. CM amplitude was suppressed. These effects were most profound at high frequencies and were typically significant at isoflurane concentrations of 2.5% and 3%. Amplitude and latency of the second negative peak of the CAP (N(2)) were affected to a greater extent compared to the first peak (N(1)). On average, isoflurane dose-dependently reduced the amplitude and increased the latency of the ABR. These effects were typically significant at an isoflurane concentration of 2%. Effects on peak IV and V were more pronounced compared to the early peaks I and III.