Evaluation of the efficacy of desflurane with or without labetalol for hypotensive anesthesia in middle ear microsurgery

Perioperative Low Dose Dexmedetomidine and Its Effect on the Visibility of the Surgical Field for Middle Ear Microsurgery: A Randomised Controlled Trial

Background and Purpose: There are many benefits of administering dexmedetomidine perioperatively. The pharmacokinetics (PK) and pharmacodynamics (PD) of intravenous, intranasal and oral dexmedetomidine that was administered before anesthesia were compared in this study, and the effects of dexmedetomidine on the surgical field visibility in tympanoplasty was evaluated. Methods: A single-blind, randomized controlled trial was conducted in a university-affiliated hospital where 45 patients who underwent tympanoplasty under general anesthesia were randomly allocated into three groups. Dexmedetomidine was administered by intravenous infusion at 0.8 μg.kg^-1 for 10 min, intranasal instillation at a drop rate of 1 μg.kg^-1 and oral intake at 4 μg.kg^-1 ten minutes before the induction of anesthesia. The PK and PD of dexmedetomidine after a single low dose administration and its effect on the surgical field in tympanoplasty were analysed. Results: A plasma concentration of dexmedetomidine of 220 pg/ml was achieved immediately after intravenous infusion and at 13.2 and 70.3 min for intranasal and oral administration, respectively. Dexmedetomidine decreased the heart rate (HR) and mean arterial pressure (MAP) in all three groups, although these values remained higher in the oral dexmedetomidine group at all eight time points. Intravenous dexmedetomidine provided the best visualization of the surgical field for opening of the tympanic sinus, 30 min after the start of the infusion (p < 0.05). Intranasal dexmedetomidine provided a significantly better visual field than oral dexmedetomidine for the repair of a tympanic membrane perforation using the fascia temporal muscle (p < 0.05). Conclusion: A single low dose of dexmedetomidine administered intravenously or intranasally could decrease HR and MAP, improve surgical field visibility and be appropriate for deliberate hypotension for surgical procedures of 1-2 h in length. Trial registration: Clinicaltrials.gov identifier: NCT03800641.

Evaluation of the perioperative effects of dexmedetomidine on tympanoplasty operations

PURPOSE

This randomized double-blind study aimed to evaluate the effects of dexmedetomidine on hemodynamic parameters and the quality of surgery and recovery criteria in tympanoplasty operations.

MATERIALS AND METHODS

A total of 75 patients 18-55 years undergoing tympanoplasty, who were graded as American Society of Anesthesiologists physical status I-II, were randomly divided into three groups. Group 1 included patients receiving remifentanil alone, Group 2 included patients receiving dexmedetomidine + remifentanil and Group 3 included patients receiving dexmedetomidine + ½ remifentanil. Anesthesia was induced with propofol and cisatracurium. For maintenance of anesthesia, a mixture of 2-2.5% sevoflurane, 40-60% oxygen/air was used. The groups were compared in terms of hemodynamic parameters, surgical area, recovery criteria, modified Aldrete, pain scores, additional analgesic requirements and adverse effects.

RESULTS

Mean arterial pressure and heart rate values of Group 1 were higher at the time of intubation, incision, spontaneous breathing and extubation compared to Group 2 and Group 3. Surgical field satisfaction was higher in Group 2 and Group 3 than Group 1. Spontaneous breathing, eye opening and verbal cooperation times were shorter in Group 3 compared to Group 2. Eye opening and verbal cooperation times were longer in Group 2 compared to Group 1. The 30-minute modified Aldrete scores was higher in Group 3 compared to Group 1. There was no difference between the groups in terms of postoperative pain and adverse effects.

CONCLUSION

The use of dexmedetomidine during tympanoplasty operations may provide better hemodynamic control and surgical view, may provide faster recovery and may reduce remifentanil consumption.

A randomized controlled trial evaluating the hemodynamic impact of ultrasound-guided great auricular nerve block in middle ear microsurgery

BACKGROUND

The peri-operative effectiveness of ultrasound-guided great auricular nerve block (GANB) in patients, especially in adult patients undergoing middle ear microsurgery remains unclear. We hypothesized that ultrasound-guided GANB would decrease the hemodynamic responsiveness to incision and opioid consumption in middle ear microsurgery as well as the post-operative analgesia requirement.

METHODS

Sixty patients undergoing middle ear microsurgery were randomized into two equal groups to receive either a GANB with 2 ml of 0.25% ropivacaine under ultrasound guidance (GANB group) or to receive a blank control intervention (without any performed injection) before general anesthesia inductions. The primary outcomes were hemodynamic changes of MAP (mean artery pressure) and HR (heart rate) to skin incision. The secondary endpoints were to determine the consumptions of propofol and remifentanil during the operation and the incidence of remedial analgesia 48 h post-operation to maintain VAS ≤ 3.

RESULTS

The MAP post incision in GANB group was significantly lower than that in control group (GANB group 93.83 ± 11.72 mmHg vs. control group 100.87 ± 12.65 mmHg, P = 0.029). The increases for MAP and HR post incision were also lower in GANB group (∆MAP GANB group 11.90 ± 8.32 mmHg vs. control group 19.83 ± 10.37 mmHg, P = 0.002; ∆HR GANB group 3.67 ± 5.30 beat min^- 1 vs. control group 8.23 ± 8.56 beat min^- 1, P = 0.016). Remifentanil consumption was significantly decreased in GANB group (GANB group 401.55 ± 100.51 μg h^- 1 vs. control group 697.34 ± 215.45 μg h^- 1, P = 0.000). The incidence of remedial analgesia post-operation in GANB group (5/30) was significantly lower than that in control group (20/30, P = 0.000).

CONCLUSION

Ultrasound-guided GANB decreases the hemodynamic responsiveness to incision and remifentanil consumption in middle ear microsurgery as well as the post-operative analgesia requirement.

TRIAL REGISTRATION

This trial was retrospectively registered at http://www.chictr.org.cn with the registration number of ChiCTR1800014333 on 6 January, 2018.