Efficacy of constant flow oxygen supply via laryngeal mask airway combined with a thin tube at distal end of airway stenosis for intraoperative ventilation in patients with severe tracheal stenosis undergoing bronchoscopy / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the efficacy of constant flow oxygen supply via laryngeal mask airway combined with a thin tube at the distal end of airway stenosis for intraoperative ventilation in the patients with severe tracheal stenosis undergoing bronchoscopy. Methods:Forty patients of either sex, aged 18-70 yr, scheduled for comprehensive interventional therapy with tracheoscope for severe tracheal stenosis, were allocated into 2 groups ( n=20 each) by a random number table method: test group and control group.After routine anesthesia induction, intermittent positive pressure ventilation was supplied via a laryngeal mask airway linked to four-way connector and anesthesia machine.In test group, a 6Fr suction tube was inserted through the four-way connector and placed at the distal end of the stenosis, with 1 L/min flow oxygen supply.Before ventilation with the thin tube (T 0), at 30 min after start of mechanical ventilation (T 1), and at the end of operation (T 2), SpO 2, P ETCO 2, mean airway pressure (Pmean), and minute ventilation (MV) were recorded, monitoring of lung ventilation was implemented using electrical impedance tomography, and the area percentages of the centre of ventilation (CoV), dependent silent spaces (DSS), and non-dependent silent spaces (NSS) were recorded.Blood gas analysis was performed at T 1 to record pH value, PaO 2 and PaCO 2.Hypoxemia was recorded during ventilation. Results:Compared with control group, MV, Pmean and area percentage of NSS were significantly increased and area percentage of DSS was decreased at T 1, 2, P ETCO 2 was decreased and SpO 2 and area percentage of CoV were increased at T 1, pH value and PaO 2 were increased, and PaCO 2 and the incidence of hypoxemia were decreased in test group ( P<0.05). Conclusion:Combination of laryngeal mask airway and a thin tube at the distal end of airway stenosis for constant flow oxygen supply can improve the ventilation efficacy by increasing the oxygen concentration at the distal end of the stenosis and by reopening the collapsed lung tissue at the distal end during interventional therapy with tracheoscope in the patients with severe tracheal stenosis.