AJA Asian Journal of Anesthesiology

Advancing, Capability, Improving lives

Case Report
Volume 51, Issue 2, Pages 90-93
Kuo-Chuan Hung 1
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Abstract

The Trachway intubating stylet is designed to facilitate tracheal intubation in anesthetized patients with a normal or difficult airway anatomy. The shortcoming of this device is the lack of a working channel to provide topicalization of the airway. We describe a novel modified method of using Trachway intubating stylet to provide airway topicalization and perform awake orotracheal intubation in two cases with an anticipated difficult airway. The first case was a superobese patient with a cervical spine disorder, whereas the second case was a patient with an enlarged thyroid gland. Transtracheal lidocaine injection was technically difficult in these patients because of neck obesity and thyroid enlargement, respectively. We believe that this modified method can be used to provide effective airway topicalization when Trachway intubating stylet is used for awake orotracheal intubation.

Keywords

intubation; intratracheal; laryngoscopy; Trachway intubating stylet;


1. Introduction

Awake fiber-optic intubation is often the method of choice to manage anticipated difficult airway. However, the fiber-optic bronchoscope (FOB) is costly, and a skilled operator may be required to successfully intubate patients with a difficult airway. Many video-intubation devices are commercially available, and the availability of these devices gives the practitioners an alternative selection to the customarily more commonly preferred fiber-optic approach for awake tracheal intubation.123 The Trachway intubating stylet (Trachway), also known as the Clarus Video System (Biotronic Instrument Enterprise Ltd., Taichung, Taiwan, R.O.C.), is a video-intubating stylet.4 This device reportedly facilitated effective tracheal intubation in anesthetized patients with cervical collars.5 Recent case reports have also described the use of Trachway to facilitate tracheal intubation in anesthetized or awake patients with an immobilized neck.67 The shortcoming of Trachway is its lack of a working channel; furthermore, the spray-as-you-go technique8 cannot be used with this device. In this report, we describe a novel modified method of using Trachway to provide airway topicalization to perform awake orotracheal intubation in two patients with an anticipated difficult airway. Administration of transtracheal lidocaine injection was difficult in these two patients because of a bulky neck and an enlargement of the thyroid gland, respectively.

2. Case report

The first patient was a 30-year-old man (weight: 122 kg; height: 156 cm; body mass index: 50.1 kg/m2) who was diagnosed with C4–6 stenosis and was scheduled to undergo spinal fusion. A preoperative physical examination revealed that he had progressive bilateral lower limb weakness and decreased sensation in both the upper and lower extremities. Airway assessment revealed a limited mouth opening of 3 cm, a short thick neck, and a Mallampati class 3 airway. Identification of the cricothyroid membrane was difficult in this patient because of his short, thick neck. Direct laryngoscopy for tracheal intubation could entail the risk of spinal cord injury and failed tracheal intubation because of the cervical spine disease combined with superobesity. Therefore, we decided to perform awake tracheal intubation with Trachway.

The second patient was an 80-year-old woman (weight: 62 kg; height: 160 cm; body mass index: 24.2 kg/m2) with perforated peptic ulcer requiring exploratory laparotomy. A physical examination of her airway revealed a 3-cm mouth opening, excessive thyroid enlargement, and a Mallampati class 3 airway (Fig. 1). Although there were no symptoms of airway compromise, a preoperative chest X-ray revealed a deviated trachea. Because of the thyroid enlargement and tracheal deviation, direct laryngoscopy for tracheal intubation would entail the risk of tracheal intubation failure. Therefore, we decided to perform awake tracheal intubation with Trachway.

Fig. 1.
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Fig. 1. An 80-year-old woman with excessive thyroid enlargement. A physical examination of the airway reveals a 3-cm mouth opening and a Mallampati class 3 airway.

A transtracheal block was not attempted for these two patients because of stout neck and excessive thyroid enlargement, respectively. The Trachway does not have a working channel or a special external tube adapter that allows for the administration of a local anesthetic solution. Therefore, a novel modified method, which allowed for airway topicalization using the spray-as-you-go technique, was used.

First, we connected the OptiPort right-angle, double-swivel connector of a double-lumen tube (Broncho-Cath; Mallinckrodt, Athlone, Ireland) to the machine end of a tracheal tube connector (Fig. 2A). A 6-Fr suction tube was then passed through the side-arm orifice of the double-swivel connector and inserted into the lumina of the tracheal tube until its tip projected just beyond the tip of the tracheal tube (Fig. 2B). The lubricated Trachway was inserted into the tracheal tube through another port on the double-swivel connector. The end of the double-swivel connector fitted well into the Trachway. The stylet tip of Trachway was close to, but did not protrude beyond, the distal end of the tracheal tube. The tip of the suction tube was visible from the monitor on the Trachway (Fig. 2C), which allowed the operator to ascertain the correct position of the suction tube tip. It should be noted that the suction tube was inserted into the lumina of the tracheal tube first, following which the Trachway was inserted into the lumina of the tracheal tube.

Fig. 2.
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Fig. 2. A double-swivel connector of the double-lumen tube is used as an external tube adapter for the Trachway. (A) A size 7 tracheal tube or larger can accommodate both the stylet and a 6-Fr suction tube. (B) The suction tube is inserted into the lumina of the tracheal tube through the side-arm orifice of the double-swivel connector, with its tip projecting just beyond the tip of the tracheal tube. The stylet tip is close to, but does not protrude beyond, the distal end of the tracheal tube. (C) The tip of the suction tube is visible from the monitor on the Trachway.

The two patients were placed in supine position with their head and neck in neutral position. After routine monitors were applied, the patients were preoxygenated with 6 L/minute of oxygen. Intravenous (IV) atropine (0.01 mg/kg) was administered as an antisialagogue. The oral and pharyngeal mucosa was anesthetized with 10% topical lidocaine spray. In the first patient, 50 mg ketamine and 100 μg fentanyl were administered for conscious sedation. In the second patient, increasing doses of propofol (40 mg in total) were used for conscious sedation. After inserting an oral bite block, the assembly was inserted into the mouth at the midline and slowly advanced. The neck of the first patient was maintained in a neutral position without performing a jaw thrust. During our first attempt, the view of Trachway was obscured by secretions, and the attempt was abandoned. After oral suctioning, it was possible to see the tip of the epiglottis resting on the posterior pharyngeal wall. The tip of the stylet was moved laterally to cross the epiglottis, and the laryngeal aperture was identified during the second attempt. In the second patient, a jaw thrust was performed to clear the airway, because the vocal cords were identified during the first attempt without difficulty.

After the glottis was identified, the tip of the suction tube was advanced under direct visualization into the trachea when the glottis opened at the beginning of inhalation. Following this, 3 mL of 2% lidocaine was injected into the trachea through the suction tube. After approximately 30 seconds, the assembly was further advanced into the trachea. When the tip of the tracheal tube was placed below the glottis, an additional 3 mL of 2% lidocaine was injected into the trachea through the suction tube. No cough response or gagging reflex was elicited throughout the airway topicalization. Approximately 30 seconds after completion of airway topicalization, the tracheal tube was advanced over the rigid stylet and inserted into the trachea. The rigid stylet and suction tube were simultaneously removed, leaving the tracheal tube in place. End-tidal capnography confirmed tracheal placement, and routine IV induction was performed.

The trachea was intubated in both patients by a single anesthesiologist, who had the required knowledge and skill for using the Trachway in anesthetized patients. Assisted ventilation was not required throughout the procedure, and pulse oxygen saturation was maintained at >95%. During airway manipulation, patients were encouraged to indicate their discomfort by lifting their hand. Insertion of the assembly was well tolerated without any discomfort or gagging. The entire process from the insertion of the assembly to inflation of the cuff of the tracheal tube required <3 minutes. Only a weak cough was elicited upon introduction of the tracheal tube, and the hemodynamic profile of both patients was relatively stable. No evidence of trauma was noted upon visual inspection of the oropharynx immediately after the procedure. No perioperative complications related to airway management were observed.

3. Discussion

Reduced mouth opening (interincisor distance <3.5 cm), thyromental distance <6 cm, reduced neck movement, thyroid enlargement accompanied by airway deformity,9 prominent teeth, obesity,10 and Mallampati class 3–4 airways are recognized predictors of a difficult intubation.11 Patient 1 had four risk factors, whereas Patient 2 had three of the aforementioned risk factors. In such situations, FOB may be the preferred instrument, but maintenance of the psychomotor skills required for FOB can be a problem for inexperienced users. The availability of video-intubating devices allows the clinician to intubate the trachea of patients more safely and easily compared with conventional laryngoscopes. Undoubtedly, these devices may serve as a replacement for FOB when awake tracheal intubation is indicated for a patient. To reduce patients' discomfort and avoid the possibility of laryngospasm during awake tracheal intubation, adequate airway topicalization is often necessary. This report demonstrates that this modified method can allow for the use of the spray-as-you-go technique to provide airway topicalization effectively when Trachway is used.

Some problems that were encountered during airway management in our first patient should be addressed. First, although the Trachway stylus tip within the end of the tracheal tube was kept free of oral secretions during the intubating process, visualization was still hindered by excessive oral secretion. This problem was solved by suctioning the pharynx prior to the second attempt. Second, an excess of airway tissue in obese patient may impede a free view when using the video-intubating stylet. Although the Trachway stylet was used to displace the excess airway tissue in this patient, the duration of the intubation attempt may be prolonged and therefore increase discomfort to the conscious patient. In addition, the presence of a large floppy epiglottis with the head in a neutral position led to the epiglottis being completely apposed to the posterior pharyngeal wall in this patient. A jaw thrust or the head-tilt maneuver may be performed to elevate the hyoid bone and lift the epiglottis through the hyoepiglottic ligament in such cases.12 However, we did not perform these maneuvers in our first patient in order to avoid possible injury due to the cervical spine disease. In this case, we found that it required greater skill to advance the stylet tip beyond the epiglottis. Lingual traction13and the use of a laryngoscope are alternative methods to clear the airway in the absence of contraindications.

Although awake intubation is most commonly selected for patients with a difficult airway, gag, cough, and laryngospasm in response to intubation may be troublesome. The Trachway does not have a working channel and a special external tube adapter, which allows for lidocaine spray, is not available for this device. Some modified methods have been described previously for the lightwand or other rigid fiber-optic stylets to provide airway topical anesthesia.141516 These modified methods prompted us to use the double-swivel connector of a double-lumen tube as an external tube adapter for the Trachway. Using this modified method, airway topicalization was achieved under fiber-optic view, and the direction of the lidocaine stream to the targeted sites could be controlled more accurately. In addition, the proximal end of the suction tube can also be connected to an oxygen tube to provide supplemental oxygen or to blow away saliva. It should be noted that initial trachea topicalization should be completed with only the tip of the suction tube below the glottis because injection of local anesthetic solution into the trachea may provoke a cough response. Airway damage may occur during an unexpected cough if the assembly is within the trachea.

Compared with video laryngoscopes, awake tracheal intubation with the Trachway has some advantages. First, awake tracheal intubation with Trachway can decrease discomfort as this intubating device does not incorporate a blade. Positioning the tip of the video laryngoscope blade posterior to the epiglottis and lifting the tongue base may create a greater degree of discomfort in conscious patients.1718 Second, airway topicalization can be achieved using the spray-as-you-go technique if the modified method is applied. For some video laryngoscopes without a channel, airway topicalization can only be completed with the inspiration of atomized lidocaine or a transtracheal block. Third, the tip of the Trachway can be positioned below the glottis, which minimizes the chances of inadvertent tube misplacement into the esophagus and decreases the risk of impingement on the laryngeal structures during tracheal tube advancement. In addition, the small diameter of the Trachway (determined just by the external diameter of the attached tracheal tube) makes it very useful in patients with limited mouth opening.

There are limitations of our report. First, only a size 7 tracheal tube (or larger) can accommodate the 6-Fr suction tube and the Trachway. If a smaller tracheal tube is used, an epidural catheter should be used as an alternative to the suction tube. Second, because the tracheal intubation was performed by an experienced anesthesiologist, the efficacy of this modified method in using Trachway to provide airway topicalization when used by inexperienced users remains unknown.

In conclusion, this report shows that the modified method of using Trachway to provide airway topicalization allows for smooth orotracheal intubation in conscious patients with an anticipated difficult airway. Because of the advantage of reducing patient discomfort while maintaining a spontaneous respiration, this modified method may be considered as an alternative management for the anticipated difficult airway.


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References

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