The Efficacy of Transnasal Humidified Rapid-insufflation Ventilatory Exchange During Laryngeal Microsurgery

Study Overview
=================
Brief Summary
-----------------
Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) was revealed to prolong apneic time with a slow increase in carbon dioxide; thus, has been used for preoxygenation in patients with difficult airways or requiring rapid sequence induction in general anesthesia. However, in patients undergoing hypopharyngeal and laryngo-tracheal surgery, THRIVE during operation can be advantageous by allowing tubeless surgical field with sufficient oxygenation. Therefore, the investigators conducted this study to evaluate the efficacy of THRIVE on prolonged apneic time with enhanced surgical conditions in patients with laryngeal microsurgery.

Detailed Description
-----------------
Patients undergoing laryngeal microsurgery will be randomized into either intubation group or THRIVE group. On arriving operating room, the patients will be preoxygenated by facemask or high flow nasal cannula with 100% oxygen for 3 minutes according to the allocated group. After inducing general anesthesia, patients in intubation group will be oxygenated by endotracheal tube, while patients in THRIVE group will be oxygenated by high flow nasal cannula with flow rate of 70L/min. During the surgery, the endotracheal tube can be removed and reintubated in intubation group patients to provide surgical field by a surgeon, respectively. The monitored pulse oximetry, oxygen reserve index, and transcutaneous partial pressure of carbon dioxide will be recorded during surgery.

Official Title
-----------------
The Efficacy of Transnasal Humidified Rapid-insufflation Ventilatory Exchange in Patients Undergoing Laryngeal Microsurgery: a Randomized Controlled Trial

Conditions
-----------------
Apneic Oxygenation

Intervention / Treatment
-----------------
* Procedure: endotracheal intubation
* Procedure: high flow nasal cannula


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: patients undergoing laryngeal microsurgery ASA class I-III Exclusion Criteria: patients scheduled for laryngeal microsurgery using CO2 laser patients with increased intracranial pressure patients with skull base defect patients with chronic obstructive pulmonary disease patients with pulmonary hypertension patients requiring rapid sequence induction

Ages Eligible for Study
-----------------
Minimum Age: 20 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: intubation group<br>The enrolled patients will be oxygenated by endotracheal tube during operation. | Procedure: endotracheal intubation<br>* After preoxygenation with FiO2 1.0 and flow rate of 8 L/min for 3 minutes, the enrolled patients will be intubated with endotracheal tube and maintained oxygenation during surgery.<br>|
| Experimental: THRIVE group<br>The enrolled patients will be oxygenated by intubationless high flow nasal cannula during operation. | Procedure: high flow nasal cannula<br>* After preoxygenation with 100% oxygen through high flow nasal cannula for 3 minutes, the enrolled patients will be maintained intubationless oxygenation with flow rate of 70 L/min during surgery.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| lowest oxygen saturation | lowest oxygen saturation monitored by pulse oximetry during laryngeal microsurgery | from the time of starting laryngeal microsurgery till the end of the surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| lowest oxygen reserve index | lowest oxygen reserve index monitored during laryngeal microsurgery | from the time of starting laryngeal microsurgery till the end of the surgery | 
| highest transcutaneous partial pressure of carbon dioxide | highest transcutaneous partial pressure of carbon dioxide monitored during laryngeal microsurgery | from the time of starting laryngeal microsurgery till the end of the surgery | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
airway management, high flow nasal cannula, laryngeal microsurgery