The Brazilian Journal of Anesthesiology granted permission to reuse Table 1 and Figure 3.

The study, approved by the &#34;Iuliu Ha&#539;ieganu&#34; University of Medicine and Pharmacy Ethics Committee (no. 100/12.02.2018) and registered under ClinicalTrials.gov identifier NCT03546088, enrolled adult patients with ASA physical status I-IV8. These individuals had distorted airway anatomy due to laryngopharyngeal pathology and were scheduled for surgery under general anesthesia. Informed consent was obtained from all participants. The inclusion criteria were a Simplified Airway Risk Index (SARI) score of 4 or higher and distorted airways from laryngopharyngeal masses, prior radiotherapy, or inflammation, with awake intubation deemed the safest method following ENT and pre-anesthetic evaluations8. Exclusion criteria included obstructed nasal passages, bleeding disorders, allergy to local anesthetics, lack of understanding or cooperation, or refusal of the procedure, in which case an alternative airway management approach was suggested8. The details of the reagents and equipment used in the study are listed in the Table of Materials.
1. Preoperative assessment
<ol>
	<li>Consider awake flexible scope intubation in every patient with potentially complex airway management and in patients who may benefit from maintaining spontaneous ventilation and intrinsic airway tone until the placement of an endotracheal tube4.</li>
	<li>Perform a careful pre-anesthetic airway assessment, including an ENT exam, imagistic examinations, and bedside inspection. Obtain a complete patient history (including previous surgical interventions, airway history, radiotherapy in the cervical area, snoring, or obstructive sleep apnea) and execute a careful clinical exam.</li>
	<li>Calculate the SARI score (comprising of mouth opening, thyromental distance, Mallampati score, neck mobility, ability to prognath, weight, and history of difficult intubation) and consider the patient at risk of difficult intubation if the score &#8805;4 (maximum 12 points)9.</li>
	<li>Conclude the preoperative airway evaluation with trans-nasal flexible nasopharyngolaryngoscopic examination whenever there is a suspicion of airway pathology10. Position the patient sitting upright. Apply xylometazoline 0.1% and lidocaine spray 10% in both nostrils.</li>
	<li>Advance the flexible rhino-laryngoscope through one of the nares beneath the inferior turbinate until it reaches the nasopharynx. Pause when the tongue base or the epiglottis are visible, and inspect the hypopharynx and the glottis. Urge the patient to sniff, protrude the tongue, vocalize, or breathe deeply to improve visualization6,10 (Supplementary Video 1). 
	NOTE: When performing the procedure in an emergency, such as extensive edema or large friable tumoral masses, use added care, as even a minor injury could lead to complete airway obstruction.</li>
	<li>Utilise point of care ultrasonography (POCUS) to evaluate airway difficulty and review relevant imaging (such as computer tomography or magnetic resonance imaging scans) to anticipate the optimal path for the endotracheal tube (ETT) and determine the appropriate tube size. Identify and mark the cricothyroid membrane and the trachea in case emergency front-of-the-neck access is needed11.</li>
	<li>Considering the examinations provided, assess whether awake fiberoptic intubation is the best option for airway management, considering that the loss of spontaneous breathing or other airway techniques may pose a significant risk. Begin the preparations for awake intubation.</li>
	<li>Explain the procedure to the patient and obtain informed consent. Emphasize the risks of intubation after anesthesia induction in problematic airway patients and the safety benefits of an awake technique. Inform the patient to expect a mild level of discomfort but reassure them that topical anesthesia and light sedation will be provided.</li>
</ol>
2. Equipment preparation and checklist
<ol>
	<li>Keep in mind that successful awake intubation requires careful planning. Before starting the procedure, ensure all necessary personnel and infrastructure are available.</li>
	<li>Follow the checklist for awake intubation recommended by The Difficult Airway Society (DAS) to improve performance and ensure that essential steps are not missed5.</li>
	<li>Safeguard that at least one anesthetist, separate from the airway operator, and an anesthesia nurse are present to assist during the procedure. Additionally, have an ENT team on standby for an emergency tracheostomy in the event of obstructive airway pathology.</li>
	<li>Ensure the patient&#39;s physiologic monitors are immediately visible when manipulating the airway. Check that the supplemental oxygen delivery device and suction are working.</li>
	<li>Ensure the anesthesia machine or ventilator is readily accessible and operational. Prepare the difficult airway kit, a video laryngoscope, and several alternative airway devices, including different-sized laryngeal mask airways and ventilation masks, a front-of-the-neck access kit, and different sizes and types of ETT (endotracheal tubes).</li>
	<li>Check all the airway management tools that are part of the management plan and ensure they are at hand. Prepare, dilute, and label all the medication as needed.</li>
</ol>
3. Patient preparation
<ol>
	<li>Premedicate the patient with 0.5-1 mg of midazolam intravenously (IV) and glycopyrrolate 0.2 mg IV or 0.4 mg atropine IV if glycopyrrolate is not available. Use a face mask with a nebulizer to nebulize 10 mL of lidocaine 2%-4% for 10 min at a flow rate of 3-8 L/min8. In a patient with a high risk of gastric content aspiration, administer prophylaxis to increase gastric pH and reduce gastric volume. 
	CAUTION: Do not use atropine in patients prone to tachyarrhythmia or with a high ventricular pace. In elderly, frail patients and patients with severe airway compromise due to obstructive pathology, omit sedation.</li>
	<li>Administer 100-200 mg of hydrocortisone intravenously if tissue edema leading to airway compromise is of concern8. Add 500 &#181;g of epinephrine to the nebulized lidocaine solution in patients with severe obstruction to reduce edema.</li>
	<li>Transfer the patient to the operating theater and place them on the operating table in a sitting or semi-recumbent position. Provide standard ASA monitoring: pulse oximetry, respiratory rate, non-invasive blood pressure (NIBP), ECG, end-tidal CO2, and inspired oxygen concentration.</li>
	<li>Administer lidocaine 10% and xylometazoline 0.1% nasal spray and place a nasal cannula for supplementary oxygen delivery.</li>
	<li>Evaluate the airway using the same tool prepared for awake intubation, a 300-350 mm working length flexible video rhino-laryngoscope with a diameter of 3-4 mm, identifying the most suitable nostril for passing the ETT8.
	<ol>
		<li>Check for septal deviation, bony spurs, and turbinate hypertrophy. Inspect the pharynx and the peri-glottic space (base of the tongue, vallecula, epiglottis, pyriform fossa), vocal cords, and sub-glottic region to the mid-trachea.</li>
		<li>Determine the optimal path for the ETT based on the distortion of airway anatomy by tumors or inflammation, airway compression, or deviation from the midline.</li>
	</ol>
	</li>
	<li>Estimate the appropriate ETT size (usually between 5.5-6.5 mm) based on the minimal cross-section area throughout the nasal passage, supraglottic area, and glottis until mid-tracheal level. Use ETT with softer tips to reduce the chances of impingement and injury while advancing along the airway (such as soft reinforced tubes or Parker flex-tip). Have smaller diameter ETT available in case there is a nasal or glottic blockage.</li>
	<li>Decide a final airway management plan based on the fiberoptic evaluation. Consider alternative airway strategies in patients with significant airway narrowing or massive edema, including surgical front-of-neck access under regional anesthesia.</li>
	<li>For patients undergoing awake intubation, administer midazolam 0.5-1 mg IV and fentanyl 50-100 &#181;g IV, titrating doses over 5 min intervals. Aim for an Observer&#39;s Assessment of Alertness/Sedation Scale (OAA/S) of 4-5 (oriented but cooperative and calm). Omit sedation or use carefully adjusted doses for frail patients or where airway collapse, obstruction, or inadequate ventilation is of concern8. 
	NOTE: Sedative medication should be administered with high precaution by the assisting anesthetist, who watches the patient carefully. Sedation should not substitute airway topicalization.</li>
	<li>Begin by administering 2% lidocaine for gargling. Then, using the working channel of the scope or a curved oropharyngeal catheter under fiberoptic guidance, in case the scope does not have a working channel, administer additional lidocaine topically, dripping over the glottis and the vocal cords. Ask the patient to inspire and vocalize during this step8.</li>
	<li>Consider the anesthesia level to be adequate when administering more lidocaine in the glottis does not elicit a cough response anymore. Insert cotton gauze soaked with a 4% lidocaine solution with ephedrine 5% along the chosen nostril and leave it in place for 2 min8. 
	CAUTION: Do not exceed a total of 9 mg/kg of lidocaine (both nebulized and topical).</li>
</ol>
4. Intervention
<ol>
	<li>After 5-7 min from sedation and topical anesthesia, start the maneuver with the flexible rhino-laryngoscope armed with an intubating tube. Use a reinforced, cuffed ETT with an internal diameter of 5.5-6.5 mm and lubricate it with 2% lidocaine gel.</li>
	<li>Place the fiberscope inside the ETT, ensuring that the proximal end of the tube covers the transitional part of the fiberscope handle. This will help stabilize the setup and allow for smooth advancement of both the fiberscope and ETT simultaneously8 (Figure 1).</li>
	<li>Ensure that the ETT does not obstruct the flexible distal tip of the fiberscope. If using a 6.5 mm ETT (320 mm long) with a 300 mm working length flexible scope, remove the connecting piece to ensure the tip of the fiberscope has unrestricted movement. 
	NOTE: There is no need to remove the connecting piece when using a flexible rhino-laryngoscope whose articulate head exceeds the tip of the ETT.</li>
	<li>Introduce the fiberscope-ETT ensemble in the selected nostril. Orient the bevel of the ETT laterally during the nasal passage, then slowly advance the fiberscope and ETT following the nasal floor and the septum as close as possible.</li>
	<li>Rotate the tube with small movements if an obstacle is encountered during the nasal passage. Aspirate secretions as needed when the scope reaches the pharynx, stop the advancement, and search for the structures of interest: epiglottis, arytenoids, or vocal cords. Maintain verbal contact with the patient during the procedure.</li>
	<li>If the glottis cannot be visualized entirely or partially due to tumors, inflammation, or extrinsic compression, reposition the patient&#39;s head by left-to-right or flexion-extension movements or urge the patient to protrude the tongue for better glottic exposure. Manipulate the fiberscope with the dominant hand while adjusting the patient&#39;s head position with the non-dominant hand8. 
	NOTE: In case of large tumors of the anterior airway, it may be useful to have an assistant holding the tongue protruded during the intervention for better glottic exposure.</li>
	<li>If the ETT and the glottis form too sharp of an angle while advancing or if an obstacle is impeding the passage of the tube, withdraw the ETT a few centimeters and rotate it 90&#176; counterclockwise. Alternatively, reposition the patient&#39;s head in the same manner as for poor glottic visualization8.</li>
	<li>To minimize discomfort, do not withdraw the ETT above the nasopharynx when attempting to reposition unless major complications occur or the patient requests so. If there is an obstruction at the level of the glottis, instruct the patient to breathe deeply while the fiberscope- ETT assembly passes the glottic aperture.</li>
	<li>Advance the tube to the mid-tracheal level. Ask the patient to take deep breaths while the fiberscope-ETT assembly advances through the tracheal lumen.</li>
	<li>Confirm proper tube placement with the tip 2-4 cm above the carina by fiberoptic visualization and remove the fiberscope.</li>
	<li>Connect the patient to the ventilator to ensure the capnography waveform is adequate and spontaneous movement of the ventilation bag is present. If using a 6.5 mm tube, reattach the connecting piece before connecting to the ventilator. Secure the ETT in position with tape and use a flexible extension corrugated tube (catheter mount) to connect the ETT to the breathing circuit.</li>
</ol>
5. General anesthesia and extubation
<ol>
	<li>Induce anesthesia after securing the airway. Use fentanyl 2-3 &#181;g/kg, propofol 2-3 mg/kg, and atracurium 0.5 mg/kg, adapting induction medication and doses to individual patients based on hemodynamic response and comorbidities.</li>
	<li>Monitor anesthesia depth, ventilation, capnography, and hemodynamic parameters. Use either a volatile-based technique or total intravenous anesthesia (TIVA) for maintenance8.</li>
	<li>Evaluate the risk for post-extubation airway compromise at the end of the procedure. Perform a cuff leak test8. Deflate the cuff of the ETT and ventilate the patients. Significant airway edema is likely if no audible air leak is present during expiration.</li>
	<li>If the risk for post-extubation airway compromise is low, ensure the patient is fully awake and responsive and extubate the trachea in the operating theatre, then monitor them closely for signs of respiratory distress or airway obstruction. Have equipment and staff for emergency reintubation immediately available.</li>
	<li>Ask the ENT surgeon to perform an airway evaluation before deciding the best course for extubation and consider ultrasonography for airway assessment. If significant edema or bleeding has occurred and the patient is at risk following extubation, transfer the patient to the intensive care unit (ICU). Keep the patient intubated and sedated for 24-48 h.</li>
	<li>Consider cortisone IV to reduce edema and reassess the patient by repeating the cuff leak test, ultrasound, and ENT exam. When extubation seems possible, have all the equipment and drugs necessary for emergency reintubation or front-of-the-neck access available. Ideally, perform the procedure in the operating room as the ergonomics are better.</li>
	<li>Aspirate the secretions and have a skilled anesthetist and ENT surgeon on standby. Consider placing an airway exchange catheter before removal of the ETT.</li>
</ol>

Awake Intubation in Difficult Airways: A Flexible Video Laryngoscope Method

<ol>
	<li>Joffe, A. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Management+of+difficult+tracheal+intubation:+A+closed+claims+analysis.">Management of difficult tracheal intubation: A closed claims analysis.</a> Anesthesiology. 131 (4), 818-829 (2019).</li><li>Cook, T. M., Woodall, N., Major Frerk, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=complications+of+airway+management+in+the+UK:+Results+of+the+fourth+national+audit+project+of+the+Royal+College+of+Anaesthetists+and+the+difficult+airway+society.+Part+1:+Anaesthesia.">complications of airway management in the UK: Results of the fourth national audit project of the Royal College of Anaesthetists and the difficult airway society. Part 1: Anaesthesia.</a> Br J Anaesth. 106 (5), 617-631 (2011).</li><li>Rosenstock, C. V., N&#248;rskov, A. K., Wetterslev, J., Lundstr&#248;m, L. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Emergency+surgical+airway+management+in+Denmark:+A+cohort+study+of+452461+patients+registered+in+the+Danish+anesthesia+database.">Emergency surgical airway management in Denmark: A cohort study of 452461 patients registered in the Danish anesthesia database.</a> Br J Anaesth. 117, i75-i82 (2016).</li><li>Apfelbaum, J. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=American+Society+of+Anesthesiologists+practice+guidelines+for+management+of+the+difficult+airway.">American Society of Anesthesiologists practice guidelines for management of the difficult airway.</a> Anesthesiology. 136 (1), 31-81 (2022).</li><li>Vora, J., Leslie, D., Stacey, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Awake+tracheal+intubation.">Awake tracheal intubation.</a> BJA Educ. 22 (8), 298-305 (2022).</li><li>Alvi, S., Harsha, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flexible+Nasopharyngoscopy.">Flexible Nasopharyngoscopy.</a> Statpearls, StatPearls Publishing. , (2024).</li><li>Paul, B. C., Rafii, B., Achlatis, S., Amin, M. R., Branski, R. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morbidity+and+patient+perception+of+flexible+laryngoscopy).">Morbidity and patient perception of flexible laryngoscopy).</a> Ann Otol Rhinol Laryngol. 121 (11), 708-713 (2012).</li><li>Marchis, I. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Awake+nasotracheal+intubation+with+a+300+mm+working+length+fiberscope:+A+prospective+observational+feasibility+trial.">Awake nasotracheal intubation with a 300 mm working length fiberscope: A prospective observational feasibility trial.</a> Braz J Anesthesiol. 73 (5), 556-562 (2023).</li><li>N&#248;rskov, A. K., Rosenstock, C. V., Wetterslev, J., Lundstr&#248;m, L. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Incidence+of+unanticipated+difficult+airway+using+an+objective+airway+score+versus+a+standard+clinical+airway+assessment:+The+difficult+trial+-+trial+protocol+for+a+cluster+randomized+clinical+trial.">Incidence of unanticipated difficult airway using an objective airway score versus a standard clinical airway assessment: The difficult trial - trial protocol for a cluster randomized clinical trial.</a> Trials. 14, 347 (2013).</li><li>Marchis, I. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trends+in+preoperative+airway+assessment.">Trends in preoperative airway assessment.</a> Diagnostics. 14 (8), 610 (2024).</li><li>Lin, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Point-of-care+ultrasound+in+airway+evaluation+and+management:+A+comprehensive+review.">Point-of-care ultrasound in airway evaluation and management: A comprehensive review.</a> Diagnostics. 13 (9), 1541 (2023).</li><li>Marchis, I. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> New methods of controlling the difficult airway in otorhinolaryngologic anesthesia&#8212;PhD Thesis. , (2022).</li><li>Fiadjoe, J. E., Litman, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Difficult+tracheal+intubation:+Looking+to+the+past+to+determine+the+future.">Difficult tracheal intubation: Looking to the past to determine the future.</a> Anesthesiology. 116 (6), 1181-1182 (2012).</li><li>Joseph, T. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+retrospective+study+of+success,+failure,+and+time+needed+to+perform+awake+intubation.">A retrospective study of success, failure, and time needed to perform awake intubation.</a> Anesthesiology. 125 (1), 105-114 (2016).</li><li>Asai, T., Shingu, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Difficulty+in+advancing+a+tracheal+tube+over+a+fibreoptic+bronchoscope:+Incidence,+causes+and+solutions.">Difficulty in advancing a tracheal tube over a fibreoptic bronchoscope: Incidence, causes and solutions.</a> Br J Anaesth. 92 (6), 870-881 (2004).</li><li>Ahmad, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Difficult+airway+society+guidelines+for+awake+tracheal+intubation+(ati)+in+adults.">Difficult airway society guidelines for awake tracheal intubation (ati) in adults.</a> Anaesthesia. 75 (4), 509-528 (2020).</li><li>Jones, T. M., De, M., Foran, B., Harrington, K., Mortimore, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laryngeal+cancer:+United+Kingdom+national+multidisciplinary+guidelines.">Laryngeal cancer: United Kingdom national multidisciplinary guidelines.</a> J Laryngol Otol. 130, S75-S82 (2016).</li><li>Rosenblatt, W., Ianus, A. I., Sukhupragarn, W., Fickenscher, A., Sasaki, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preoperative+endoscopic+airway+examination+(PEAE)+provides+superior+airway+information+and+may+reduce+the+use+of+unnecessary+awake+intubation.">Preoperative endoscopic airway examination (PEAE) provides superior airway information and may reduce the use of unnecessary awake intubation.</a> Anesth Analg. 112 (3), 602-607 (2011).</li><li>Tsunoda, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Emergency+videoendoscopic+endonasal+tracheal+intubation+for+severe+upper+airway+stenosis.">Emergency videoendoscopic endonasal tracheal intubation for severe upper airway stenosis.</a> Am J Otolaryngol. 42 (2), 102779 (2021).</li><li>Kramer, A., M&#252;ller, D., Pf&#246;rtner, R., Mohr, C., Groeben, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fibreoptic+vs.+videolaryngoscopic+(c-mac+d-blade)+nasal+awake+intubation+under+local+anaesthesia.">Fibreoptic vs. videolaryngoscopic (c-mac d-blade) nasal awake intubation under local anaesthesia.</a> Anaesthesia. 70 (4), 400-406 (2015).</li></ol>

The authors have nothing to disclose.

There are several reasons why awake fiberoptic intubation is a relatively uncommon practice: it seems challenging to learn, the skill requires regular training to maintain proficiency, or a previous bad experience with this technique combined with the reluctance of an awake patient about the procedure13,14.
When using a 600 mm fiberscope, the practitioners concentrate on how to hold the fiberscope in position, which may dilute their fo...

Airway management has developed substantially over the last 20 years, but difficulties or failures in securing the airway still occur and can lead to permanent disabilities and mortality1. Patients with known or unknown pathologies of the base of the tongue, hypopharynx, glottic aperture, or trismus pose a risk of difficult or impossible facemask ventilation, supraglottic device placement, and tracheal intubation after the induction of general anesthesia1,2,3.
Standard preoperative airway examinations often fail to reveal these lesions due to discrete accompanying clinical signs and symptoms2,3. Awake flexible scope intubation is considered the gold standard in securing the airway in such cases because it allows for spontaneous respiration, preserves airway reflexes, and mitigates the risks of losing the airway or bronchopulmonary aspiration4. Despite its benefits, awake intubation remains an underused technique, even when indicated (around 1% of all intubations), due to reservations regarding its use related to lack of practice or the pressure of a busy operating theatre2,4. With the development of airway control devices, awake intubation now includes procedures employing flexible scopes, rigid or semirigid optical stylets, and video laryngoscopes5.
Nasopharyngeal flexible endoscopy, sometimes referred to as flexible nasopharyngoscopy, flexible nasolaryngoscopy, transnasal flexible laryngoscopy, or flexible fiberoptic nasopharyngolaryngoscopy, is a medical technique that aids the practitioner in examining the nasal passages, nasopharynx, oropharynx, hypopharynx, and larynx6. It is a routine instrument in ENT (ear, nose, and throat) practice and has the advantage of being minimally invasive and easy to handle7. Its use has expanded across different medical specialties, including maxillofacial surgery, anesthesiology, speech and language therapy, and neurology. In an office or hospital setting, flexible rhinolaryngoscopy provides a valuable assessment of the airway and alerts healthcare providers to the presence of pathological pharyngolaryngeal structures that may impact airway management.
The flexible fiberoptic endoscope used for the adult population has a rigid part designed to be used with one hand and a flexible fiber optic cable. The effective length of the scope is between 300 and 350 mm with a flexibility of 130&#730; to 160&#730;. The flexible tip has a length of 20 mm with a visualization angle of 80&#730; to 90&#730; in newer models. The depth of field can be easily adjusted with the handpiece roller, ranging from 3 to 60 mm. The diameter of the insertion tube may range from 3 mm to 4.5 mm, and certain models are equipped with a working or suction channel (Figure 1). Technology has advanced further, and the device has evolved from fiberoptic to new chip-on-the-tip flexible digital scopes, ensuring high-resolution imaging6,7.
Traditionally, practitioners perform awake flexible scope intubation using a fiberoptic bronchoscope with a 600 mm working length5. This protocol, based on a previous prospective study8, aims to describe in detail a technique for awake nasotracheal intubation using a 300 mm flexible rhino-laryngoscope.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Anesthesia machinne</td>
			<td>Draeger Fabius Plus</td>
			<td>1x RS232</td>
			<td></td>
		</tr>
		<tr>
			<td>Cricothyrotomy Kit</td>
			<td>CHINOOK MEDICAL GEAR, INC</td>
			<td>2160-36401</td>
			<td></td>
		</tr>
		<tr>
			<td>Ephedrine 50 mg/mL</td>
			<td>Zentiva</td>
			<td>59447636327627</td>
			<td></td>
		</tr>
		<tr>
			<td>Epinephrine 1 mg/mL</td>
			<td>Terapia SA</td>
			<td>5944702207310</td>
			<td></td>
		</tr>
		<tr>
			<td>Face mask nebulizer</td>
			<td>Ningbo Luke Medical devices</td>
			<td>RT012-100</td>
			<td></td>
		</tr>
		<tr>
			<td>Fentanyl 0.05 mg/mL</td>
			<td>Chiesi</td>
			<td>W58348002</td>
			<td></td>
		</tr>
		<tr>
			<td>flexible extension corrugated tube -catheter mount</td>
			<td>Ningbo Yingbe Medical Instruments</td>
			<td>YM-A040</td>
			<td></td>
		</tr>
		<tr>
			<td>Irrigation cannula</td>
			<td>Carl Roth</td>
			<td>HPY 2.1</td>
			<td>blunt tip, curved, 80 mm long irrigation cannula suitable for airway topicalisation</td>
		</tr>
		<tr>
			<td>Lidocaine 2%, 4%</td>
			<td>Zentiva</td>
			<td>5944705004046</td>
			<td></td>
		</tr>
		<tr>
			<td>Lidocaine gel 2%</td>
			<td>Montavit</td>
			<td>9001505008066</td>
			<td></td>
		</tr>
		<tr>
			<td>Lidocaine spray 10%</td>
			<td>Egis&#160;</td>
			<td>5995327112169</td>
			<td></td>
		</tr>
		<tr>
			<td>Midazolam 5 mg/mL</td>
			<td>Aquetant</td>
			<td>P438804058</td>
			<td></td>
		</tr>
		<tr>
			<td>Reinforced endotracheal tubes oral/nasal</td>
			<td>Create Biotech L</td>
			<td>019-002-1065</td>
			<td></td>
		</tr>
		<tr>
			<td>TelePack X Led Monitor</td>
			<td>Karl Storz</td>
			<td>200450 20</td>
			<td>HIGH RESOLUTION MONITOR, LED LIGHT SOURCE, FULL HD CAMERA CONTROL UNIT&#160;</td>
		</tr>
		<tr>
			<td>Video Rhino-Laryngoscope</td>
			<td>Karl Storz</td>
			<td>11101 VP</td>
			<td>Video Rhino-Laryngoscope direction of view 0&#176;, angle of view 85&#176;, deflection up/down 140&#176;/140&#176;, working length 30 cm</td>
		</tr>
		<tr>
			<td>Vital signs monitor</td>
			<td>Mindray</td>
			<td>N17- E392290</td>
			<td></td>
		</tr>
		<tr>
			<td>Xylometazoline 1 mg/mL</td>
			<td>Biofarma</td>
			<td>59463429</td>
			<td></td>
		</tr>
	</tbody>
</table>

the flexible rhino-laryngoscope for awake nasotracheal intubation

Difficulties or failures in securing the airway still occur and can lead to permanent disabilities and mortality. Patients with head and neck pathologies obstructing airway access are at risk of airway management failure once they lose spontaneous respiration. Awake flexible scope intubation is considered the gold standard for controlling the airway in such patients. Following a feasibility trial involving 25 patients with challenging airways, this article presents a step-by-step protocol for awake nasotracheal intubation using a flexible video rhino-laryngoscope, which is significantly shorter than conventional intubating flexible scopes. The flexible video laryngoscope only exceeds the intubating tube length by a few centimeters, allowing the tube to closely follow the flexible scope during the procedure. Once the scope reaches the pharynx, it can be easily manipulated with one hand, enabling the operator to focus on the safe advancement of the scope-intubating tube assembly through the glottis. Based on previous results and experience gained, this article highlights the potential benefits of the technique: the opportunity for a minimally invasive "quick look" preoperatively to establish a final management plan, a more convenient and safer tool for navigating distorted anatomy with a lower chance of intubating tube impingement and airway injury, and a fast and smooth procedure resulting in improved patient satisfaction.

This article aims to describe in detail a technique for awake nasotracheal intubation using a 300 mm flexible rhino-laryngoscope. In the first study, 25 out of 32 consecutive patients, aged between 34 years and 82 years, were considered suitable for awake tracheal intubation and included in the trial (Table 1)8. Each patient&#39;s trachea was successfully intubated using a flexible rhino-laryngoscope. The average &#177; standard deviation duration from the insertion of the intubat...

Author Spotlight: Advancing Awake Nasotracheal Intubation with Flexible Video Rhino-Laryngoscopes

Presented here is a protocol for awake nasotracheal intubation using a flexible rhino-laryngoscope with a 300 mm working length. As this tool is minimally invasive and easy to manipulate, awake intubation performed with a flexible rhino-laryngoscope is well-tolerated, fast, and safe for patients with difficult airways.

The Flexible Rhino-Laryngoscope for Awake Nasotracheal Intubation

Difficulties or failures in securing the airway still occur and can lead to permanent disabilities and mortality. Patients with head and neck pathologies ...

the-flexible-rhino-laryngoscope-for-awake-nasotracheal-intubation

Research

JoVE Journal

Medicine

469 Views.  “Iuliu Haţieganu” University of Medicine and Pharmacy. Presented here is a protocol for awake nasotracheal intubation using a flexible rhino-laryngoscope with a 300 mm working length. As this tool is minimally invasive and easy to manipulate, awake intubation performed with a flexible rhino-laryngoscope is well-tolerated, fast, and safe for patients with difficult airways.

Video: Author Spotlight: Advancing Awake Nasotracheal Intubation with Flexible Video Rhino-Laryngoscopes

A Novel Rescue Technique for Difficult Intubation and Difficult Ventilation

We describe a novel non surgical technique to maintain oxygenation and ventilation in a case of difficult intubation and difficult ventilation, which works especially well with poor mask fit.
Can not intubate, can not ventilate" (CICV) is a potentially life threatening situation. In this video we present a simulation of the technique we used in a case of CICV where oxygenation and ventilation were maintained by inserting an endotracheal tube (ETT) nasally down to the level of the naso-pharynx while sealing the mouth and nares for successful positive pressure ventilation.
A 13 year old patient was taken to the operating room for incision and drainage of a neck abcess and direct laryngobronchoscopy. After preoxygenation, anesthesia was induced intravenously. Mask ventilation was found to be extremely difficult because of the swelling of the soft tissue. The face mask could not fit properly on the face due to significant facial swelling as well. A direct laryngoscopy was attempted with no visualization of the larynx. Oxygen saturation was difficult to maintain, with saturations falling to 80%. In order to oxygenate and ventilate the patient, an endotracheal tube was then inserted nasally after nasal spray with nasal decongestant and lubricant. The tube was pushed gently and blindly into the hypopharynx. The mouth and nose of the patient were sealed by hand and positive pressure ventilation was possible with 100% O2 with good oxygen saturation during that period of time. Once the patient was stable and well sedated, a rigid bronchoscope was introduced by the otolaryngologist showing extensive subglottic and epiglottic edema, and a mass effect from the abscess, contributing to the airway compromise. The airway was secured with an ETT tube by the otolaryngologist.This video will show a simulation of the technique on a patient undergoing general anesthesia for dental restorations.

We describe a technique to maintain oxygenation and ventilation using an endotracheal tube inserted nasally to the level of the naso-pharynx while sealing the mouth and nares for successful positive pressure ventilation.

We describe a novel non surgical technique to maintain oxygenation and ventilation in a case of difficult intubation and difficult ventilation, which ...

Intra-Operative Behavioral Tasks in Awake Humans Undergoing Deep Brain Stimulation Surgery

Deep brain stimulation (DBS) is a surgical procedure that directs chronic, high frequency electrical stimulation to specific targets in the brain through implanted electrodes. Deep brain stimulation was first implemented as a therapeutic modality by Benabid et al. in the late 1980s, when he used this technique to stimulate the ventral intermediate nucleus of the thalamus for the treatment of tremor 1. Currently, the procedure is used to treat patients who fail to respond adequately to medical management for diseases such as Parkinson's, dystonia, and essential tremor. The efficacy of this procedure for the treatment of Parkinson's disease has been demonstrated in well-powered, randomized controlled trials 2. Presently, the U.S. Food and Drug Administration has approved DBS as a treatment for patients with medically refractory essential tremor, Parkinson's disease, and dystonia. Additionally, DBS is currently being evaluated for the treatment of other psychiatric and neurological disorders, such as obsessive compulsive disorder, major depressive disorder, and epilepsy. 
DBS has not only been shown to help people by improving their quality of life, it also provides researchers with the unique opportunity to study and understand the human brain. Microelectrode recordings are routinely performed during DBS surgery in order to enhance the precision of anatomical targeting. Firing patterns of individual neurons can therefore be recorded while the subject performs a behavioral task. Early studies using these data focused on descriptive aspects, including firing and burst rates, and frequency modulation 3. More recent studies have focused on cognitive aspects of behavior in relation to neuronal activity 4,5. This article will provide a description of the intra-operative methods used to perform behavioral tasks and record neuronal data with awake patients during DBS cases. Our exposition of the process of acquiring electrophysiological data will illuminate the current scope and limitations of intra-operative human experiments.

Deep brain stimulation surgery offers a unique opportunity to examine information encoding in the awake human brain. This article will describe intra-operative methods used to perform cognitive and behavioral tasks while simultaneously acquiring physiological data such as EMG, single-unit neuronal activity and/or local field potentials.

Deep brain stimulation (DBS) is a surgical procedure that directs chronic, high frequency electrical stimulation to specific targets in the brain through ...

Guidelines for Elective Pediatric Fiberoptic Intubation

Fiberoptic intubation in pediatric patients is often required especially in difficult airways of syndromic patients i.e. Pierre Robin Syndrome. Small babies will desaturate very quickly if ventilation is interrupted mainly to high metabolic rate. We describe guidelines to perform a safe fiberoptic intubation while maintaining spontaneous breathing throughout the procedure. Steps requiring the use of propofol pump, fentanyl, glycopyrrolate, red rubber catheter, metal insuflation hook, afrin, lubricant and lidocaine spray are shown.

We describe guidelines to perform a safe and efficient elective fiberoptic intubation in pediatric patients while maintaining spontaneous ventilation.

Fiberoptic intubation in pediatric patients is often required especially in difficult airways of syndromic patients i.e. Pierre Robin Syndrome. Small ...

Intranasal Administration of CNS Therapeutics to Awake Mice

Intranasal administration is a method of delivering therapeutic agents to the central nervous system (CNS). It is non-invasive and allows large molecules that do not cross the blood-brain barrier access to the CNS. Drugs are directly targeted to the CNS with intranasal delivery, reducing systemic exposure and thus unwanted systemic side effects1. Delivery from the nose to the CNS occurs within minutes along both the olfactory and trigeminal neural pathways via an extracellular route and does not require drug to bind to any receptor or axonal transport2. Intranasal delivery is a widely publicized method and is currently being used in human clinical trials3.
Intranasal delivery of drugs in animal models allows for initial evaluation of pharmacokinetic distribution and efficacy. With mice, it is possible to administer drugs to awake (non-anesthetized) animals on a regular basis using a specialized intranasal grip. Awake delivery is beneficial because it allows for long-term chronic dosing without anesthesia, it takes less time than with anesthesia, and can be learned and done by many people so that teams of technicians can dose large numbers of mice in short periods. Efficacy of therapeutics administered intranasally in this way to mice has been demonstrated in a number of studies including insulin in diabetic mouse models 4-6 and deferoxamine in Alzheimer's mouse models. 7,8
The intranasal grip for mice can be learned, but is not easy and requires practice, skill, and a precise grip to effectively deliver drug to the brain and avoid drainage to the lung and stomach. Mice are restrained by hand using a modified scruff in the non-dominant hand with the neck held parallel to the floor, while drug is delivered with a pipettor using the dominant hand. It usually takes 3-4 weeks of acclimating to handling before mice can be held with this grip without a stress response. We have prepared this JoVE video to make this intranasal delivery technique more accessible.

A method to intranasally administer drugs to awake mice for the purpose of targeting the brain is described. This method allows for repeat dosing over long periods using intranasal administration of drug without anesthesia, and nose-to-brain delivery with minimal systemic exposure.

Intranasal administration is a method of delivering  therapeutic agents to the central nervous system (CNS). It is  non-invasive and allows large ...

Noninvasive Intratracheal Intubation to Study the Pathology and Physiology of Mouse Lung

The use of a model that mimics the condition of lung diseases in humans is critical for studying the pathophysiology and/or etiology of a particular disease and for developing therapeutic intervention. With the increasing availability of knockout and transgenic derivatives, together with a vast amount of genetic information, mice provide one of the best models to study the molecular mechanisms underlying the pathology and physiology of lung diseases. Inhalation, intranasal instillation, intratracheal instillation, and intratracheal intubation are the most widely used techniques by a number of investigators to administer materials of interest to mouse lungs. There are pros and cons for each technique depending on the goals of a study. Here a noninvasive intratracheal intubation method that can directly deliver exogenous materials to mouse lungs is presented. This technique was applied to administer bleomycin to mouse lungs as a model to study pulmonary fibrosis.

The use of a model that mimics the condition of lung diseases in humans is critical for studying the pathophysiology and/or etiology of a particular disease and for developing therapeutic intervention. Here a noninvasive intratracheal intubation method that can directly deliver exogenous materials to mouse lungs is presented.

The use of a model that mimics the condition of lung diseases in humans is critical for studying the pathophysiology and/or etiology of a particular ...

Intubation-mediated Intratracheal (IMIT) Instillation: A Noninvasive, Lung-specific Delivery System

Respiratory disease studies typically involve the use of murine models as surrogate systems. However, there are significant physiologic differences between the murine and human respiratory systems, especially in their upper respiratory tracts (URT). In some models, these differences in the murine nasal cavity can have a significant impact on disease progression and presentation in the lower respiratory tract (LRT) when using intranasal instillation techniques, potentially limiting the usefulness of the mouse model to study these diseases. For these reasons, it would be advantageous to develop a technique to instill bacteria directly into the mouse lungs in order to study LRT disease in the absence of involvement of the URT. We have termed this lung specific delivery technique intubation-mediated intratracheal (IMIT) instillation. This noninvasive technique minimizes the potential for instillation into the bloodstream, which can occur during more invasive traditional surgical intratracheal infection approaches, and limits the possibility of incidental digestive tract delivery. IMIT is a two-step process in which mice are first intubated, with an intermediate step to ensure correct catheter placement into the trachea, followed by insertion of a blunt needle into the catheter to mediate direct delivery of bacteria into the lung. This approach facilitates a &#62;98% efficacy of delivery into the lungs with excellent distribution of reagent throughout the lung. Thus, IMIT represents a novel approach to study LRT disease and therapeutic delivery directly into the lung, improving upon the ability to use mice as surrogates to study human respiratory disease. Furthermore, the accuracy and reproducibility of this delivery system also makes it amenable to Good Laboratory Practice Standards (GLPS), as well as delivery of a wide range of reagents which require high efficiency delivery to the lung.

Intubation-mediated Intratracheal IMIT Instillation: A Noninvasive, Lung-specific Delivery System

Intubation-mediated intratracheal (IMIT) instillation of reagents is an excellent, noninvasive method for studying respiratory disease, as well as a method for instilling therapeutic reagents directly into the lung. It is a rapid and highly reproducible method which is suitable for preclinical testing.

Respiratory disease studies typically involve the use of murine models as surrogate systems. However, there are significant physiologic differences ...

An Improved Method for Rapid Intubation of the Trachea in Mice

Despite some anatomical and physiological differences, mouse models continue to be an essential tool for studying human lung disease. Bleomycin toxicity is a commonly used model to study both acute lung injury and fibrosis, and multiple methods have been developed for administering bleomycin (and other toxic agents) into the lungs. However, many of these approaches, such as transtracheal instillation, have inherent drawbacks, including the need for strong anesthetics and survival surgery. This paper reports a quick, reproducible method of intratracheal intubation that involves mild inhaled anesthesia, visualization of the trachea, and the use of a surrogate spirometer to confirm exposure. As a proof of concept, 8-12 week old C57BL/6 mice were administered either 2.0 U/kg of bleomycin or an equivalent volume of PBS, and both damage and fibrotic endpoints were measured post-exposure. This procedure allows researchers to treat a large cohort of mice in a relatively short period with little expense and minimal post-procedure care.

This article presents a rapid and simple method for administering bleomycin directly into the mouse trachea via intubation. Key advantages of this method are that it is highly reproducible, easy to master, and does not require specialized equipment or lengthy recovery times.

Despite some anatomical and physiological differences, mouse models continue to be an essential tool for studying human lung disease. Bleomycin toxicity ...

Topical Airway Anesthesia for Awake-endoscopic Intubation Using the Spray-as-you-go Technique with High Oxygen Flow

A patient&#39;s willingness to cooperate is an absolute precondition for successful awake intubation of the trachea. Whilst drug-sedation of patients can jeopardize their spontaneous breathing, topical anesthesia of the airway is a popular technique. The spray-as-you-go technique represents one of the simplest opportunities to anesthetize the airway mucosa. The application of local anesthetic through the working channel of the flexible endoscope is a widespread practice for anesthetists as well as pulmonologists. There is neither need for additional devices nor special training as a pre-requisite to perform this technique. However, a known clinical problem is the coughing and gagging reflex that may occur when the liquid anesthetic strikes the airway mucosa and other sensitive structures like the vocal cords. This can be avoided by the use of oxygen applied through the working channel with the aim of fogging the local anesthetic into finer particles. Furthermore, the oxygen flow provides a higher oxygen supply and contributes to a better view, dispersing mucus secretions and blood away from the lens. Using an atomizer with a high oxygen flow of 10 L/min we maximized these benefits, caused less coughing and had more satisfied and therefore cooperative patients. Possible, but very rare complications of using oxygen flow including gastric insufflation, organ rupture or barotrauma did not arise. We attribute the complication-free use of high oxygen flow to the design of the set, which permits flow and pressure release.

The topical anesthetic lidocaine was atomized using a high oxygen flow through the working channel of a flexible intubating endoscope to achieve topical airway anesthesia for awake endotracheal intubation. We prefer this modified spray-as-you-go technique for endoscopic intubation to classical bolus application because of higher patient satisfaction and better compliance.

A patient&#39;s willingness to cooperate is an absolute precondition for successful awake intubation of the trachea. Whilst drug-sedation of patients can ...

Evaluating the Procedure for Performing Awake Cystometry in a Mouse Model

Awake filling cystometry has been used for a long time to evaluate bladder function in freely moving mice, however, the specific methods used, vary among laboratories. The goal of this study was to describe the microsurgical procedure used to implant an intravesical tube and the experimental technique for recording urinary bladder pressure in an awake, freely moving mouse. In addition, experimental data is presented to show how surgery, as well as tubing type and size, affect lower urinary tract function and recording sensitivity. The effect of tube diameter on pressure recording was assessed in both polyethylene and polyurethane tubing with different internal diameters. Subsequently, the best performing tube from both materials was surgically implanted into the dome of the urinary bladder of male C57BL/6 mice. Twelve-hour, overnight micturition frequency was recorded in healthy, intact animals and animals 2, 3, 5, and 7 days post-surgery. At harvest, bladders were assessed for signs of swelling using gross observation and were subsequently processed for pathological analysis. The greatest extent of bladder swelling was observed on day 2 and 3, which correlated with behavioral voiding data showing significantly impaired bladder function. By day 5, bladder histology and voiding frequency had normalized. Based on the literature and evidence provided by our studies, we propose the following steps for in vivo recording of intravesical pressure and voided volume in an awake mouse: 1) Perform the surgery using an operating microscope and microsurgical tools, 2) Use polyethylene-10 tubing to minimize movement artifacts, and 3) Perform cystometry on post-operative day 5, when bladder swelling resolves.

This study describes the surgical procedures and experimental techniques for performing awake cystometry in a freely moving mouse. In addition, it provides experimental evidence to support its optimization and standardization.

Awake filling cystometry has been used for a long time to evaluate bladder function in freely moving mice, however, the specific methods used, vary among ...

Fat-Water Phantoms for Magnetic Resonance Imaging Validation: A Flexible and Scalable Protocol

As new techniques are developed to image adipose tissue, methods to validate such protocols are becoming increasingly important. Phantoms, experimental replicas of a tissue or organ of interest, provide a low cost, flexible solution. However, without access to expensive and specialized equipment, constructing stable phantoms with high fat fractions (e.g., &#62;50% fat fraction levels such as those seen in brown adipose tissue) can be difficult due to the hydrophobic nature of lipids. This work presents a detailed, low cost protocol for creating 5x 100 mL&#160;phantoms with fat fractions of 0%, 25%, 50%, 75%, and 100% using basic lab supplies (hotplate, beakers, etc.) and easily accessible components (distilled water, agar, water-soluble surfactant, sodium benzoate, gadolinium-diethylenetriaminepentacetate (DTPA) contrast agent, peanut oil, and oil-soluble surfactant). The protocol was designed to be flexible; it can be used to create phantoms with different fat fractions and a wide range of volumes. Phantoms created with this technique were evaluated in the feasibility study that compared the fat fraction values from fat-water magnetic resonance imaging to the target values in the constructed phantoms. This study yielded a concordance correlation coefficient of 0.998 (95% confidence interval: 0.972-1.00). In summary, these studies demonstrate the utility of&#160;fat phantoms for validating adipose tissue imaging techniques across a range of clinically relevant tissues and organs.

The purpose of this work is to describe a protocol for creating a practical fat-water phantom that can be customized to produce phantoms with varying fat percentages and volumes.

As new techniques are developed to image adipose tissue, methods to validate such protocols are becoming increasingly important. Phantoms, experimental ...