Evaluation the Efficiency of Intravenous Dexmedetomidine Under HFNO Without Intubation in Laryngoscope Microsurgery

Method This single-center randomized-controlled trial is conducted to compare the efficiency of LMS with intubated general anesthesia(ITGA) and LMS with nonintubated anesthesia. The study also performed a comparative evaluation of the safety and feasibility of LMS with nonintubated general anesthesia under two different ventilation strategies. The investigators plan to enroll patients aged between 20 and 80 years who required LMS.

This study has divided into three groups: the first group was LMS patients receiving general intubation general anesthesia(ITGA group). The second group consisted of LMS patients who received non-intubated general anesthesia and performed SLNB(SLNB group). The third group was LMS patients who received non-intubated general anesthesia and were given Dexmedetomidine(Dex group)

Background Laryngeal microsurgery(LMS) is among the most common operations in otolaryngology and typically requires general anesthesia administered through endotracheal tube intubation. Endotracheal tube intubation provides stable gas exchange, protects the airways by preventing secretions from falling into the lower respiratory tract, and enables the monitoring of parameters such as tidal volume and end-tidal carbon dioxide(CO2).

Nonintubated anesthesia applied in combination with transnasal humidified rapid-insufflation ventilatory exchange or high-flow nasal oxygen(HFNO) is another option for LMS. LMS with nonintubated anesthesia can avoid the complications caused by endotracheal tube intubation such as oral tissue trauma, tracheal trauma, and dental injury. Furthermore, LMS with nonintubated anesthesia can provide a clearer surgical field of vision that allows the vocal cords to be comprehensively inspected and treated.

Current practice in LMS with nonintubated anesthesia is to perform superior laryngeal nerve block(SLNB) to help avoid bucking during the procedure. However, performing SLNB is an invasion procedure can lead to some complication such as bleeding, nerve injury or vessel injury.

Therefore, the investigators investigated the administration of dexmedetomidine with intravenous general anesthesia, it is can help the patient maintain spontaneous breathing, and provide higher surgical safety during LMS with nonintubated anesthesia.

Method This single-center randomized-controlled trial is conducted to compare the efficiency of LMS with intubated general anesthesia(ITGA) and LMS with nonintubated anesthesia. The study also performed a comparative evaluation of the safety and feasibility of LMS with nonintubated general anesthesia under two different ventilation strategies. The investigators plan to enroll patients aged between 20 and 80 years who required LMS.

This study has divided into three groups: the first group was LMS patients receiving general intubation general anesthesia(ITGA group). The second group consisted of LMS patients who received non-intubated general anesthesia and performed SLNB(SLNB group). The third group was LMS patients who received non-intubated general anesthesia and were given Dexmedetomidine(Dex group) The exclusion criteria were as follows: presence of severe airway obstruction, severe airway disease, American Society of anesthesiologists(ASA) physical state \> III, pregnancy, or body mass index(BMI)≥40kg/m2.

This project is expected to improve the success rate of microlaryngoscopy in non-intubated anesthetized patients, in addition to the excellent surgical field and complete vocal cord examination, the use of dexmedetomidine instead of SLNB can provide good safety for non-intubated LMS .

Eligibility Criteria:
Inclusion Criteria:

* Subjects are between 20-80 years old.
* Patients undergoing laryngoscope microsurgery.
* Anesthesiologists rated ASA as between I and III.

Exclusion Criteria:

* Having drug dependence and drinking habits.
* Abnormal heart, liver and kidney function.
* Allergic reactions to narcotic drugs.
* Emergency surgery.
* pregnancy.
* Refuse to participate.
* BMI ≥ 40 kg/m2.