Optimizing the Endotracheal Tube Cuff Position in Adult Patients with Tracheal Diverticulum Undergoing General Anesthesia: A Case Report

Abstract

Tracheal diverticulum (TD) is a paratracheal air cyst communicating with the trachea through an ostium. Administering general anesthesia with positive pressure ventilation in TD carries the risk of diverticulum rupture, leading to complications. To mitigate these risks, it is crucial to seal/bypass the ostium using an endotracheal tube (ETT) cuff, which may require deeper placement. Deeper placement can increase the likelihood of unintended endobronchial intubation, particularly in patients with a short trachea. We describe here the fiberoptic bronchoscopy-assisted technique of intubation, where the TD ostium was successfully identified and sealed using a single-lumen ETT cuff in a 60-year-old man who underwent C4-T1 intramedullary tumor excision with an incidental TD. Anesthesiologists should have a detailed knowledge of the size, location of the ostium, the extent of TD, and its compressive effects on the trachea, which enables them to select an appropriate intubation technique using a correct size ETT to seal/bypass the orifice while preventing complications.

Keywords

diverticular ostium - general anesthesia - positive pressure ventilation - tracheal diverticulum

Introduction

Tracheal diverticulum (TD) is a paratracheal air cyst communicating with the trachea through an evident or hidden ostium.[1] Its prevalence ranges from approximately 0.3 to 8.1%.[1] [2] [3] TD is typically found on the right posterolateral aspect of the trachea, at the level of the sternoclavicular joint (T2 vertebral body), approximately 4 to 5 cm from the vocal cords or just a few centimeters above the carina.[4] This location is common because it serves as a transitional zone between the extrathoracic and intrathoracic sections of the trachea, which lack esophageal support. TD is often diagnosed incidentally, although patients may also present with chronic cough, recurrent respiratory tract infections, hoarseness, dyspnea, and stridor.[2] [4] When administering general anesthesia (GA) with intermittent positive pressure ventilation (IPPV) in patients with TD, there is a risk of pneumothorax, subcutaneous emphysema, and pneumomediastinum due to TD rupture.[5] [6] [7] [8] To mitigate these risks, it is crucial to bypass/seal the ostium of the TD using an endotracheal tube (ETT) cuff, which may require deeper fixation of the ETT than typically recommended based on the vocal cord guide (black line). However, deeper placement increases the risk of unintended endobronchial intubation due to the increased cuff and distal tip lengths (the distance from the distal end of the cuff to the tip of the ETT).[1] Both vary depending on the size of the ETT and the manufacturer. While fixing the single-lumen ETT based on the vocal cord guide (black line at vocal cord), commonly used ETTs (Portex, Rusch, Shiley) often fail to completely seal the ostium, as the cuff lies too cephalad to the ostium. If the ETT is placed too caudally in an attempt to occlude the ostium, there may be a risk of endobronchial intubation, especially in patients with a short neck and trachea. There are no recommendations regarding the type of ETT to use in patients with a short trachea, with the goal of sealing the ostium without the risk of endobronchial intubation.

Case Report

A 60-year-old male with diabetes mellitus on oral hypoglycemic agents presented with neck pain (6 months) and bilateral upper limb weakness (4 months) affecting the distal muscles, accompanied by paresthesia without bowel or bladder symptoms. Upon examination, he had bilateral grade 4 weakness in elbow extension, grade 3 weakness in wrist flexion and extension, and a diminished hand grip. A magnetic resonance imaging spine (contrast) revealed an ill-defined, heterogeneously enhancing, T2 hyperintense intramedullary lesion measuring 50 × 6 × 7 mm, spanning from C4 to T1 [Fig. 1A]. Additionally, a well-defined oval-shaped air density was noted in the right paratracheal region adjacent to the trachea, measuring 3.11 × 2.58 × 4.58 cm (anteroposterior × transverse × craniocaudal), extending from T1 to T3, reported as TD with an ostium of 4.4 mm communicating with the trachea, with the ostium of the TD at the level of T2 ([Fig. 1B]).

Fig. 1 (A) Magnetic resonance imaging (MRI) spine (T2-weighted) image shows an ill-defined, heterogeneously enhancing, hyperintense intramedullary lesion measuring 50 × 6 × 7 mm, spanning from C4 to T1 (black arrow), along with cord edema from C2 to T5 level. (B) Computed tomography (CT) thorax shows a tracheal diverticulum along the posterolateral wall of trachea extending from T1 to T3 (black arrow). (C) Fiberoptic bronchoscopy shows the ostium of tracheal diverticulum on the right posterolateral wall of trachea with the endotracheal tube in situ anteriorly.

The patient underwent C4-T1 laminoplasty and excisional biopsy under total intravenous anesthesia with motor-evoked potential monitoring. Given the favorable assessment of the airway (thin, long neck, and trachea), a decision was made to perform muscle paralysis with rocuronium and fiberoptic bronchoscopy (FOB)-assisted intubation using a 7.5-mm ETT (Portex). FOB-guided intubation was chosen to visualize the ostium of the TD, study its relationship with the vocal cords and carina, avoid airway trauma by blindly inserting the ETT, and for the precise placement of the ETT cuff over the ostium to seal the opening.

While performing FOB, a 4-mm communication was visualized on the right posterolateral wall of the trachea, 4 to 5 cm from the carina. Initially, the ETT cuff was positioned deeper (the ETT tip was 1 cm above the carina), and after cuff inflation, IPPV was initiated. While continuing ventilation, the FOB was carefully reintroduced para-axially along the posterior wall of the trachea, and the ostium of the TD was reidentified ([Fig. 1C]). IPPV was then suspended, the cuff was deflated, and the ETT was withdrawn in the cephalad direction. The center of the cuff was positioned at the ostium. The cuff was then reinflated to a pressure of 24 to 25 cm H₂O, and IPPV was resumed. At this pressure, the outer surface of the cuff was completely in contact with the inner wall of the trachea, ensuring that the opening of the TD was completely sealed, as confirmed by FOB. This ensured that the ostium of the TD was sealed off, preventing inflation of the diverticulum during IPPV, which could lead to rupture of the TD and its associated complications. The ETT tube was fixed at 24 cm from the angle of the mouth.

After the ETT cuff was appropriately positioned, the FOB was reintroduced coaxially to check the tip of the ETT in relation to the carina, revealing an ETT-carinal distance of 1.5 cm. In our case, as the patient had a long neck and trachea, it was possible to occlude the ostium using a single-lumen ETT cuff while maintaining an ETT-carinal distance of 1.5 cm, thereby avoiding the risk of endobronchial intubation. Additionally, as the surgical procedure required prone positioning and the neck was kept in a neutral position using skull pin fixation, the likelihood of ETT migration during surgery was minimal. The patient was ventilated using pressure-controlled ventilation with a pressure support of 11 to 12 cm H₂O, a peak end-expiratory pressure of 5 cm H₂O, and a respiratory rate of 12/min to achieve a tidal volume of 7 to 8 mL/kg and an end-tidal carbon dioxide level of 32 to 33 mm Hg. The procedure was completed without any intraoperative complications, and the patient was successfully extubated upon completion of the procedure. Biopsy revealed a low-grade glioma, and the patient recovered uneventfully.

Discussion

TD is a paratracheal air cyst that can be congenital or acquired. Congenital TD is often due to the abnormal development of the primary lung bud, which is often seen in males and has a small ostium and cartilaginous rings, often asymptomatic. A chronic increase in the intraluminal pressure of the trachea (bronchial asthma and chronic obstructive pulmonary disease), iatrogenic trauma during airway management, and tracheomalacia are the causes of acquired TD, which often has a wider ostium without cartilaginous rings.[3] [9]

There are reports of ventilatory failure, difficult lung isolation, airway collapse, and barotrauma due to altered anatomy while anesthetizing patients with TD.[5] [6] [10] Hence, anesthesiologists need to have an in-depth understanding of the size and location of the ostium of the TD and its relationship with the vocal cords and carina, as well as the size and extent of the TD and its compressive effects on the trachea during preoperative evaluation. Preoperative evaluation should include thin-sliced multidetector computed tomography (CT) of the chest to study the details of TD and its relation to the trachea and vocal cords, as well as preoperative bronchoscopy under sedation with adequate topicalization (to prevent violent coughing and straining) to further examine the details of TD. The primary aim while anesthetizing patients with TD undergoing GA with IPPV should be to seal or bypass the ostium of the TD. As the ostium is often located close to the carina, carinal stimulation or endobronchial intubation is often encountered while sealing or bypassing the ostium, as it requires deeper placement of the ETT.

To seal the ostium of the TD while simultaneously preventing endobronchial intubation in an adult patient with TD, the ETT should have a cuff length of at least 30 mm with a short distal tip (< 20 mm).[1] None of the routinely used single-lumen ETTs has a short distal tip. In patients with TD and a long trachea, a routinely available single-lumen ETT can be used by fixing the ETT deeper, avoiding carinal stimulation or endobronchial intubation. However, for patients with a short trachea, there are no specific recommendations or guidelines regarding the use of a specific type and size of ETT. We analyzed various options based on their cuff and distal tip lengths and suggesting the following options: (1) use of a left double-lumen tube (DLT) without inflating the bronchial cuff. The tracheal cuff of the DLT is long enough and more distally placed, which seals the ostium of the TD. However, its use is routinely practiced only for thoracic surgery involving the resection of large TD close to the carina.[9] [11] (2) The next alternative is to use a 6.5-mm internal diameter (ID) microcuff tube (MCT), which has a thin polyurethane cuff that seals better at a lower cuff pressure with a short distal tip (17 mm). One disadvantage is that the cuff length is relatively short (20 mm); therefore, it must be placed precisely over the ostium. (3) The third alternative is to use a 6-mm microlaryngeal tube (MLT), which has a wider rectangular cuff with a short distal tip (17 mm). Because both the 6-mm MLT and 6.5-mm MCT have short distal tips (< 20 mm) compared to the normal adult ETT, which has a distal tip of 28 to 32 mm, the safety margin of these tubes increases by 10 mm. When using a smaller ETT, the cuff must be inflated under FOB guidance, and one should ensure that the inflated cuff seals the ostium. The cuff length, distal tip length of commonly used single-lumen ETTs, 6.0 mm ID MLT, 6.5 mm MCT, and the left DLT of various sizes are presented in [Table 1].

Table 1 The cuff length and the distal tip length of various types of endotracheal tubes

ETT type and size	Tracheal cuff length	Distal tip length
Portex ETT (7 mm ID)	32 mm	28 mm
Portex ETT (7.5 mm ID)	32 mm	28 mm
Portex ETT (8 mm ID)	32 mm	28 mm
Portex ETT (8.5 mm ID)	32 mm	32 mm
Left DLT (41 F)	45 mm	15 mm
Left DLT (39 F)	45 mm	15 mm
Left DLT (37 F)	40 mm	10 mm
Left DLT (35 F)	40 mm	10 mm
MLT (6 mm ID)	32 mm	17 mm
MCT (6.5 mm ID	20 mm	17 mm

Abbreviations: DLT, double-lumen tube; ETT, endotracheal tube; ID, internal diameter; MCT, microcuff tube; MLT, microlaryngeal tube.

Dynamic CT reports have shown that paratracheal air cysts vary in size during spontaneous forced respiration; they contract during forced inspiration and expand during forced expiration without an evident ostial opening in the trachea, indicating communication into the trachea.[10] Utilizing this concept, an ultrasound-guided placement of the ETT cuff to bypass the ostium of TD has been reported.[12] In patients with TD with a hidden orifice, the ETT tube cuff must be placed as distally as possible into the trachea without risking endobronchial intubation.

Conclusion

Every anesthesiologist should have an in-depth understanding of the size, location of the ostium, and the extent of the TD and its compressive effects on the trachea. This understanding will allow them to select the appropriate intubation techniques and tracheal tube size to effectively seal or bypass the orifice while minimizing the risk of complications.

Conflict of Interest

None declared.

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Publication History

Article published online:
12 December 2025