Effects of Thermal Softening of Double-Lumen Endobronchial Tubes on the Prevention of Postoperative Sore Throat in Smokers: A Randomized Controlled Trial.

OBJECTIVE: Tracheal intubation-related complications, such as postoperative sore throat (POST), hoarseness, and vocal cords injuries, are not uncommon. It is well known that thermal softening of double-lumen endobronchial tubes (DLTs) has been used to prevent these events from happening in non-smokers; however, no study has ever assessed the effects of thermal softening of DLTs in smokers undergoing one-lung anesthesia. The authors aimed to investigate whether thermal softening of DLT can achieve a better effect in preventing POST. DESIGN: A total of 258 smokers scheduled for one-lung anesthesia were randomly assigned to 1 of the following 2 groups: (1) group C (non-thermal softening group) and (2) group T (DLTs were placed in 40°C 0.9% saline for 10 minutes). Incidence and severity of POST and hoarseness were assessed until 48 hours after surgery. Vocal cords were examined using laryngoscope before intubation and immediately after extubation. Patients' hemodynamic change at intubation and extubation was recorded. The primary outcomes were the incidence and severity of POST. The secondary outcomes were the incidence and severity of hoarseness, vocal cords injuries, and patients' hemodynamic change at intubation and extubation. MEASUREMENTS AND MAIN RESULTS: Sore throat and vocal cord injuries occurred less frequently in the thermal softening group than in the control group (31/129 v 60/129, p < 0.01; 21/129 v 49/129, p < 0.001; 12/129 v 35/129, p < 0.001 for sore throat; 14/70 v 27/70, risk ratio (95% confidence interval): 0.52 (0.30-0.90), p = 0.025 for sore throat; 5/129 v 52/129, p < 0.05 for vocal cord injuries). CONCLUSION: Thermal softening of DLTs significantly reduced the incidence and severity of DLTs intubation-related POST within 72 hours after extubation.

[Effects of repeated sevoflurane exposure on hippocampal cell apoptosis and long-term learning and memory ability in neonatal rats].

Objective: To investigate the effects of repeated sevoflurane exposure on hippocampal cell apoptosis and long-term learning and memory ability in neonatal rats and its regulation on PI3K/AKT pathway. Methods: Ninety SD rats were randomly divided into the control group (25% oxygen), the single exposure group (inhalation of 3% sevoflurane and 25% oxygen on the 6th day after birth), the 3-times exposure group (inhalation of 3% sevoflurane and 25% oxygen on the 6th, 7th, and 8th day after birth), the 5-times exposure group (inhalation of 3% sevoflurane and 25% oxygen on the 6th, 7th, 8th, 9th and 10th day after birth), and the 5-times exposure + 740Y-P (PI3K activator) group (intraperitoneal injection of 0.02 mg/kg 740Y-P after inhalation of sevoflurane for 5 times) according to the random number table method. Morris water maze was used to measure the learning and memory ability; HE staining and transmission electron microscopy were used to observe the morphological and structural changes of neurons in the hippocampus; TUNEL was used to detect the apoptosis of hippocampal nerve cells; Western blot was used to detect the expressions of apoptosis-related proteins (Caspase-3, Bax, Bcl-2) and PI3K/AKT pathway related proteins in the hippocampus of rats. Results: Compared with the control group and the single exposure group, the learning and memory abilities of rats in the 3-times exposure group and the 5-times exposure group were severely reduced, the morphology and structure of hippocampal neurons were severely damaged, and the apoptosis rate of hippocampal nerve cells was increased (P＜0.05), the expressions of Capase-3 and Bax proteins were significantly increased (P＜0.05), and the expressions of Bcl-2 protein and PI3K/AKT pathway protein were significantly decreased (P＜0.05). With the increase in the number of exposures to sevoflurane, the learning and memory abilities of rats were significantly reduced, the hippocampal neuron cells were severely damaged, the hippocampal neuronal apoptosis rate was significantly increased (P＜0.05), and the expressions of PI3K/AKT pathway proteins were significantly reduced (P＜0.05). Compared with the 5-times exposure group, the learning and memory abilities and hippocampal neuron structure of rats in the 5-times exposure +740Y-P group were restored to a certain extent, and the hippocampal neuronal apoptosis rate, the levels of capase-3 and Bax protein were significantly reduced (P＜0.05), while the expressions of Bcl-2 protein and PI3K/AKT pathway protein were increased significantly (P＜0.05). Conclusion: Repeated exposure to sevoflurane can significantly reduce the learning and memory abilities of neonatal rats and exacerbate hippocampal neuronal apoptosis, which may be mediated by inhibiting the PI3K/AKT pathway.