A new perspective during laryngo-tracheal surgery: the use of an ultra-thin endotracheal tube (Tritube®) and flow-controlled ventilation-a retrospective case series and a review of the literature

Abstract

Background: Upper airway surgery often poses a challenge to both anesthesiologists and surgeons, as airway access, mechanical ventilation, and surgical difficulties may occur in a tricky combination. To fulfill the need for a tubeless surgery, techniques such as apneic oxygenation or jet ventilation may be used, which carry the risk of several complications. The ultrathin cuffed endotracheal tube Tritube can be used with flow-controlled ventilation (FCV) to provide adequate surgical field and ventilation. To assess the feasibility, safety, and effectiveness of this technique, we describe a series of 21 patients, with various lung conditions, undergoing laryngo-tracheal surgery with FCV delivered via Tritube. Moreover, we perform a narrative systematic review to summarize clinical data on the use of Tritube during upper airway surgery.

Results: All patients were successfully intubated in one attempt with Tritube. The median (interquartile range [IQR]) tidal volume was 6.7 (6.2-7.1) mL/kg of ideal body weight, the median end-expiratory pressure was 5.3 (5.0-6.4) cmH₂O, and the median peak tracheal pressure was 16 (15-18) cmH₂O. The median minute volume was 5.3 (5.0-6.4) L/min. Median global alveolar driving pressure was 8 (7-9) cmH₂O. The median maximum level of end-tidal CO₂ was 39 (35-41) mmHg. During procedures involving laser, the maximum fraction of inspired oxygen was 0.3, with the median lowest peripheral oxygen saturation of 96% (94-96%). No complications associated with intubation or extubation occurred. In one patient, the ventilator needed to be rebooted for a software issue. In two (10%) patients, Tritube needed to be flushed with saline to remove secretions. In all patients, optimal visualization and accessibility of the surgical site were obtained, according to the surgeon in charge. Thirteen studies (seven case reports, two case series, three prospective observational studies, and one randomized controlled trial) were included in the narrative systematic review and described.

Conclusions: Tritube in combination with FCV provided adequate surgical exposure and ventilation in patients undergoing laryngo-tracheal surgery. While training and experience with this new method is needed, FCV delivered with Tritube may represent an ideal approach that benefits surgeons, anesthesiologists, and patients with difficult airways and compromised lung mechanics.

Keywords: Airway management; FCV; Flow controlled ventilation; Laryngeal surgery; Optimized ventilation; Tritube.

Fig. 1

Tritube. Cuffed endotracheal tube with 45-cm length and 4.4-mm outer diameter for adult patient ventilation in combination with FCV. Tritube has three lumens that allow (1) ventilation (2.3-mm inner diameter), (2) inflation and deflation of the cuff, and (3) measurement of intratracheal pressures

Fig. 2

Setting flow-controlled ventilation (FCV). Using FCV requires the setting of four parameters: (1) inspiration flow, (2) I:E ratio, (3) peak pressure, and (4) end-expiratory pressure (EEP). At the set flow rate, gas is insufflated from set EEP until it reaches the set peak pressure. Then, the flow is reversed and gas is sucked out at the rate to reach the set I:E ratio until EEP is reached, aiming for a linear decrease in intratracheal pressure. Then, a next insufflation with the set inspiration flow is started. Applied tidal volume results from the set driving pressure and respiratory system compliance

Fig. 3

Flow-controlled ventilation (FCV) compared to volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV). FCV requires a high resistant breathing circuit to prevent passive expiration and to fully control ventilation. FCV is a fully dynamic ventilation providing stable gas flow into and out of the patient lungs, without frequent phases of no-flow. FCV aims for linear increases and decreases in intratracheal pressures, with no sudden pressure drops at the beginning of expiration, and constant flows during inspiration and expiration

Fig. 4

Example of a patient with severe subglottic stenosis intubated with Tritube. Laryngoscopic view above (left) and under (right) the vocal cords

Fig. 5

PRISMA flow diagram indicating the citation selection process for the systematic review