Name: the rigid tube as an alternative in controlling the problematic airway
Uploaded: 2020-06-06T14:00:00
Description: Watch this Scientific Journal Video about The Rigid Tube as an Alternative in Controlling the Problematic Airway at JoVE.com

The authors have no acknowledgments. Alexandra Pop and Ioan Florin Marchis are featured in the video production that complements this article.

We designed a prospective, observational, single-center study evaluating the feasibility of tracheal intubation using the RTL with the approval of the University Ethics Committee no 432/24.11.2016 and registered with ClinicalTrials.gov NCT03341507. The study involved adult patients with ASA physical status 1&#8211;3, requiring general anesthesia for ear, parotid, and rhino-sinus surgery and having a presumed anatomically difficult airway as calculated with The Simplified Airway Risk Index (SARI) score8<...

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The most prevalent mistake when dealing with an unexpected problematic airway is to insist on the same tool and the same technique only to realize that it is not working. This makes the situation only worse by promoting edema or bleeding9.
We had the idea of testing this tool when we anesthetized a patient with a grade 4 glottic visualization at conventional laryngoscopy, according to the Cormack-Lehane classification. Since the rigid tube was prepared to investigate th...

Airway management incidents represent a large proportion of anesthesia-related mortality and severe morbidity despite the development of new tools for airway control and extensive educational resources1. The video laryngoscope and flexible or rigid endoscopes are big steps forward, but they require a supplementary investment in addition to training2,3. Difficult intubation is often unanticipated, so it is the practitioner&#39;s responsibility to have a backup plan and use the appropriate tool from those available4. This study aims to show that a cheap and straightforward tool, the rigid tube for laryngoscopy (RTL), could be efficiently used for tracheal intubation in patients with poor glottis visualization during conventional laryngoscopy.
The rigid tube for laryngoscopy (Figure 1) is a 15-25 cm long, straight, round hollow tube with a 5-20 mm diameter and a bevel end distally. It resembles a rigid bronchoscope or esophagoscope, but shorter5. A connective piece that has a prismatic light deflector with connection to a light source is attached to the proximal end of the rigid tube when in use, and the image is obtained directly, looking through this assembly. It is an instrument used by ear, nose, and throat specialists to visualize the larynx and its vicinity. In a pilot study, 20 patients with supraglottic pathology and anatomically challenging airways were intubated with the rigid tube, and the results were encouraging6.
This research included patients with anatomical criteria for difficult intubation and a modified Cormack-Lehane7 glottis view grade &#8805;2b when using a curved blade laryngoscope. The purpose was to demonstrate that laryngoscopy using the rigid tube with a retromolar approach could offer a quick glottic view in cases with poor glottic visualization at conventional laryngoscopy and the right conditions to intubate the trachea over the intubating tube introducer.

<table>
	<tbody>
		<tr>
			<td>Airway management set</td>
			<td>Karl Storz</td>
			<td>11300 B3</td>
			<td></td>
		</tr>
		<tr>
			<td>Anesthesia machine</td>
			<td>Draeger</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Anesthetic drug: Fentanyl</td>
			<td>Chiesi</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Anesthetic drug: propofol</td>
			<td>Fresenius</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Anesthetic drug: succinylcholine</td>
			<td>Takeda</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Anesthetic drugs: midazolam</td>
			<td>Aguettant</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Intubation Tube</td>
			<td>Touren</td>
			<td></td>
			<td>A 7-7.5 mm diameter is suitable for tracheal intubation over the bougie</td>
		</tr>
		<tr>
			<td>Intubation Tube Introducer (Bougie)</td>
			<td>Ontex</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Lubricating gel</td>
			<td>Dynarex</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Mcintosh laryngoscope</td>
			<td>Heine</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Rigid tube with a removable connective piece that has a prismatic light deflector attached</td>
			<td>Explorent GMBH</td>
			<td></td>
			<td>The connective piece serial number is: 650021 
			We did not find a current commercial offer for the rigid tube and the connective piece we used in this study.</td>
		</tr>
		<tr>
			<td>Table top light source with light cable</td>
			<td>Karl Storz</td>
			<td>20134001, 61594GW</td>
			<td></td>
		</tr>
	</tbody>
</table>

the rigid tube as an alternative in controlling the problematic airway

The unexpected problematic airway represents a large proportion of anesthesia-related morbidity and mortality. The retromolar or paraglossal approach is an alternative to the majority of the rigid instruments used for tracheal intubation, which follow the midline to access the glottis. This single-center, prospective case-series study offers an option to conventional laryngoscopy in case of a poor glottic view, introducing an instrument (the rigid tube for laryngoscopy) that uses the retromolar approach to accomplish tracheal intubation. If after anesthesia induction, the modified Cormack-Lehane glottis view grade &#62;2b, the intubation is carried further with the rigid tube. The tube follows the direction of the thyroid cartilage while advancing from the labial commissure, displacing the tongue to the contralateral side. Adjusting the position of the larynx with the nondominant hand by gently pushing the thyroid cartilage and following an imaginary line towards it while advancing it improves the time needed for proper glottis visualization. Once the epiglottis is in sight, the practitioner progresses slowly, lifting the epiglottis and aiming the tip of the tube more anteriorly. When the glottis appears in the visual field, the intubating tube introducer is placed in the trachea, and a lubricated cuffed intubating tube is advanced over the introducer after the rigid tube is extracted. This tool was tested on 30 patients with an unsatisfactory glottic view when using the Macintosh laryngoscope and obtained excellent results with respect to intubation time and complications. The reduced visual field is the main limitation of this method, which requires a training period for reasonable expertise. This simple, robust, and cheap instrument could be a rescue option in case of a difficult airway.

Over 24 months, we included 64 patients with a SARI &#8805;5, predictive for difficult intubation (Supplemental File 1). Thirty of them presented a modified Cormack-Lehane glottis view grade &#8805;2b during the laryngoscopy performed with the curved blade laryngoscope, so they were attempted to be tracheal intubated with the RTL (Table 1). In all cases, with one exception, the procedure with the rigid tube was successful without any incidents occurring. The patient we did not intubate, ...

Watch this Scientific Journal Video about The Rigid Tube as an Alternative in Controlling the Problematic Airway at JoVE.com

The Rigid Tube as an Alternative in Controlling the Problematic Airway

Presented here is a protocol of tracheal intubation over an intubating tube introducer using a rigid tube for laryngoscopy with an attached light source. The main characteristics of this maneuver are the retromolar approach and the use of the thyroid cartilage as a landmark while advancing the rigid tube.

The unexpected problematic airway represents a large proportion of anesthesia-related morbidity and mortality. The retromolar or paraglossal approach is ...

This study aims to show that a cheap and straightforward tool, the rigid tube for laryngoscopy, could be efficiently used for tracheal intubation in patients with poor glottis visualization during conventional laryngoscopy. A prevalent mistake when one deals with an unexpected problematic airway is to insist on the same tool and the same method only to realize that it's not working. And the situation is getting worse by promoting edema or bleeding.The retromolar or paraglossal approach is an alternative to the majority of the rigid instruments used for tracheal intubation, which follow the midline to access the glottis. We had the idea of testing this tool when we anesthetized a patient with a grade 4 glottic visualization at conventional laryngoscopy, according to the Cormack-Lehane classification. Since the rigid tube was prepared to investigate this patient, we tried it using the retromolar approach and obtained a perfect glottis view.The rigid tube for laryngoscopy is 15 to 25 centimeters long, straight, hollow tube, rounded shape with a diameter of five to 20 millimeters and a bevel end distally. An intermediate piece that has a prismatic light deflector with a connection to light source is attached to the proximal end of the rigid tube. When in use, the image is obtained directly, looking through this assemble.The patient lies on the operating table with the head placed on tilt in a sniffing position. Apply standard hemodynamic and respiratory monitoring Make sure that help from an experienced anesthetist or ENT physician is available in case of an emergency. Prepare a difficult airway kit at disposal and assemble, and check the rigid tube with light source attached.Identify the thyroid cartilage by palpation of the anterior neck. Ask the patient to extend the head and measure the distance between the labial commissure and the thyroid cartilage in a straight line. Note the length obtained on the rigid tube prepared, starting from its tip.That distance is the depth that which one should expect to find the glottis when using the rigid tube. Preoxygenate the patients for five minutes and start anesthesia induction with fentanyl, propofol, and succinylcholine. After one minute of mask ventilation, perform standard laryngoscopy with a curved blade laryngoscope, and register the modified Cormack-Lehane glottis visualization grade.If the glottis view grade is above or equal to 2b, withdraw the Macintosh laryngoscope, and maneuver further with the rigid tube. A challenge of this technique is to follow an imaginary line from the labial commissure to the thyroid cartilage while advancing the rigid tube, and adjusting the position of the larynx with the nondominant hand by gently pushing the thyroid cartilage. This motion translates to the inner structures around the glottis and helps the practitioner orientate after the tip of the tube reaches the pharynx.Cover the upper molars with a rubber teeth protector or a cotton swab on the side of the approach. Introduce the rigid tube in the oral cavity at the level of the right or left labial commissure with the bevel facing the superior arcade, the nondominant hand opens the patient's mouth, hyperextends the patient's head, and the rigid tube advances towards the pharynx. The investigator applies gentle pressure on the proximal end of the rigid tube against the protected superior molars as the tip of the tube is reaching the hypopharynx.That way, the tip of the rigid tube orientates anteriorly on the direction of the glottis. Advance the rigid tube slowly until it reaches the epiglottis, then lift the epiglottis with the tip of the device. Make sure the bevel is oriented posteriorly.At that point, the glottis should be visible. Once the glottis is in sight, place the intubating tube introducer through the rigid tube into the trachea. Do not insert the introducer too vigorously.Extract the rigid tube. Place a standard cuff lubricated intubating tube over the introducer into the trachea. Do not use force and gently rotate the intubating tube while advancing.Once the intubating tube is at the proper depth of 20 to 25 centimeters from the labial commissure, remove the intubating tube introducer leaving the intubating tube in place. Inflate the cuff and confirm tracheal intubation through lung auscultation and capnography. Over the 24 months, 30 patients with pictures predictive for difficult intubation presented the modified Cormack-Lehane glottis view grade above or equal to 2b during the laryngoscopy performed with a curved blade laryngoscope.The procedure was successful in all patients except one who desaturated to 80%In most of the cases, the intervention was straightforward, the glottis got into sight in less than 25 seconds from the start of the maneuver with the rigid tube The advancement of the intubating tube over the intubating tube introducer lasted between 20 and 30 seconds and was uneventful also. The median duration of the whole procedure starting from the moment the rigid tube entered the oral cavity until the confirmed tracheal intubation was 50 seconds. Tracheal intubation with the rigid tube offers an alternative when curved blade laryngoscopy is unsatisfactory.The reduced need for soft tissue compression is compared with the Macintosh technique comes from a better airway alignment during the retromolar approach in case of the more anterior position of the glottis. Using either side is an advantage for the left-handed and in the case of pharyngeal or cervical masses. Rigid tube is a compact instrument easy to decontaminate, resistant to long term use, and requires a minimal setup time.The main limitation of this method is the reduced visual field, proportional to the tube diameter. Dental injury and bleeding or damage of the pharyngeal injured structures during the procedure are potential complications, especially if embedded with excessive force. The use of the intubating tube introducers carries the risk of airway perforation, vocal cord injury, and the impossibility of advancing the intubating tube in the trachea.The technique needs a training period for reasonable expertise and the regular use for proficiency preservation. Although we did not find data in the literature regarding this method of airway approach, we are confident that this simple, cost-efficient technique, might prove useful as a rescue option when a practitioner encounters difficult intubation.

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