Univent tube for thoracoscopic thymectomy in myasthenic patients anesthetized without neuromuscular blocking agents: An observational study

Abstract

Background: Myasthenia gravis (MG) patients undergoing surgery may opt for general anesthesia without neuromuscular blocking agents (NMBAs). The univent tube, featuring a single lumen with bronchial blockers, is known for its flexibility and preference in challenging intubations, reducing airway damage during one-lung ventilation. This study assesses the safety and feasibility of utilizing the univent tube for thoracoscopic thymectomy in MG patients under general anesthesia without NMBAs, complemented by airway topical anesthesia.

Methods: In this single-center, prospective observational study, 83 consecutive MG patients underwent thoracoscopic thymectomy with univent tube intubation. General anesthesia without NMBAs and airway topical anesthesia were administered. Emphasis was placed on intubation conditions, surgical aspects, intraoperative respiratory, and airway complications.

Results: Clinically acceptable intubation conditions were achieved in 99% of patients, with 80% rated as 'excellent' and 19% as 'good.' No cases experienced intubation failure, and 2% exhibited reactions to tracheal tube insertion. Higher MG stages correlated with more favorable intubation conditions, particularly during laryngoscopy. Surgical conditions were excellent in 89%, and blocking the right lung increased total lung collapse, enhancing surgical conditions. Intraoperative ventilation was sufficient for all cases. Incidences of bronchial and vocal cord injuries were 6% and 10%, respectively, with no hematoma cases. Postoperative sore throat (12%) and hoarseness (6%) resolved within three days.

Conclusions: Despite the potential benefits of NMBAs, the univent tube proved safe and effective for thoracoscopic thymectomy in MG patients without NMBAs, with higher MG stages associated with improved intubation conditions and enhanced surgical conditions with right-side bronchial blockage.

Keywords: Airway management; myasthenia gravis; neuromuscular blocking agents; one-lung ventilation; thymectomy.

Figure 1

Equipment, anesthesia procedure, and study flowchart. Univent tube (a), bronchial blocker cuff was checked with bronchoscopy (b), anesthesia procedure (c), and study flowchart (d). TLV, two-lung ventilation; OLV, one-lung ventilation; ABG, arterial blood gas; ECG, electrocardiogram; IABP, invasive arterial blood pressure; SpO₂, peripheral oxygen saturation; EtCO₂, end-tidal capnography; RE, response entropy; SE, state entropy; TOF, train-of-four neuromuscular monitoring; MG, myasthenia gravis

Figure 2

Train-of-four (TOF) values at intubation time and intraoperative respiratory parameters. TOF value at intubation time (one-way analysis of variance, Tukey’s post hoc tests; a). Intraoperative respiratory including the peak airway pressure (b), peripheral oxygen saturation (SpO₂; c), and end-tidal carbon dioxide (EtCO₂; d) were recorded at two-lung ventilation (TLV) and at different time points during one-lung ventilation (OLV). Arterial blood gas parameters including pH (e), partial pressure of arterial carbon dioxide (PaCO₂; f), partial pressure of arterial oxygen (PaO₂; g), and bicarbonate level (HCO₃^-; h) were assessed at TLV and 30 minutes after establishing OLV. Data are presented as means with standard deviation