Discussion
hoarseness, impaired pulmonary function, throat, cough, postoperative adverse events such as, hypercapnia-induced, hypercapnia, non-obese, shortness of breath
ADVERSE EVENTS, WOUND BLEEDING, CORTEX
THRIVE could maintain oxygenation without blocking the view of surgical field, especially when operating lesions at the middle and lower part of vocal cords. However, the intraoperative carbon dioxide accumulation may affect the quality of emergence from general anesthesia in patients using THRIVE. LM is less irritating to the airway but not as suitable as the endotracheal tube for microlaryngeal surgery. Therefore, the potential influence of THRIVE combined with LM on the quality of emergence from anesthesia is worthy of study. Our study revealed that compared with the conventional mechanical ventilation through an endotracheal tube, patients treated with the THRIVE + LM strategy: 1. recovered spontaneous respiration, met airway tool removal and PACU discharge criteria faster; 2. had a lower incidence of cough in the PACU; 3. could maintain adequate oxygenation in a short operative time; 4. have apnea-duration related intraoperative carbon dioxide accumulation.Although THRIVE is theoretically capable of facilitating carbon dioxide clearance [After arriving at PACU, patients in the THRIVE + LM group recovered spontaneous respiration, get LM removed, and met PACU discharge criteria faster than patients in the MV + ETT group. This finding has not been reported in previous studies. We found out that the difference in duration of PACU stay between the two groups mainly derived from the shorter time of spontaneous respiration recovery, suggesting the stimulation of the respiratory center by hypercapnia may be the crucial mechanism. Carbon dioxide is an agonist of respiration, and hypercapnia at 100–150 mmHg has the most substantial agonistic effect on spontaneous respiration but is highly correlated with anesthetics used. Healthy volunteer study showed that hypercapnia-induced ventilation increase is associated with bilateral changes in activity of anterior cingulate cortex [Safaeian found that compared with an endotracheal tube, laryngeal mask reduced the incidence of postoperative adverse events such as hoarseness, cough, and shortness of breath in prolonged ENT surgeries such as functional endoscopic sinus surgery, parotid surgeries, rhinoplasty, and septoplasty, but patients with surgeries involving the throat or other lower part of the airway was excluded from the study [After 10 min of apneic oxygenation, the median PaOThis study has the following limitations. Firstly, like most previous studies, this study selected non-obese patients with healthy lungs as the study population for safety reasons. Therefore, the effects of the THRIVE + LM strategy need further study in patients with impaired pulmonary function. Secondly, the sample size of this study was relatively small. However, since the expected primary outcome is consistent with the actual one, the sample size is sufficient. Notably, the small sample size may result in a lack of data on serious adverse events, such as wound bleeding and the following aspiration. Thirdly, for practical reasons, the P