[Effects of high-flow nasal oxygen combined with early extubation on the incidence of respiratory adverse events during emergence from general anesthesia in children undergoing adenoid-tonsillectomy]

Objective: To investigate the effects of high-flow nasal oxygen (HFNO) combined with early extubation on the incidence of respiratory adverse events (RAE) during emergence from general anesthesia in children undergoing adenoid-tonsillectomy. Methods: From December 2021 to January 2022, 40 pediatric patients [21 males, 19 females, with a median age of 4 (4, 5) years] undergoing tonsillectomy and/or adenoidectomy in Eye & ENT Hospital of Fudan University were randomly divided into two groups: HFNO-assisted early extubation group (Group H, n=20) and conventional extubation group (Group C, n=20) by using a random number table. After entering the post-anesthesia care unit (PACU), the patients in group H received humidified and heated oxygen (flow rate: 25 L/min) through a nasal cannula until their consciousness regained. After patient's spontaneous breathing resumed for 10 min, the oral endotracheal tube was removed. Patients in group C did not receive HFNO. The oral endotracheal tube was removed after the patient's spontaneous breathing resumed for at least 10 min with signs of tube intolerance, or 20 min without signs of tube intolerance. During the PACU stay, the incidence of RAE, the incidence of cough, the application rate of intensive care strategy, the time to extubation, the duration of PACU stay, and vital signs at spontaneous breathing resuming and extubation in each group were recorded. Results: In Group H, the total incidence of RAE [30% (6/20) vs 65% (13/20), P=0.027], the incidence of cough [10% (2/10) vs 45% (9/20), P=0.031] and the application rate of intensive care strategy [20% (4/20) vs 55% (11/20), P=0.048] during PACU stay was significantly lower, compared with those of Group C. Likewise, the time to extubation was significantly shorter [(33.4±4.5) min vs (42.7±5.3) min, P<0.001]. However, there was no statistically significant difference in the duration of PACU stay, the vital signs at the time of spontaneous breathing resuming and extubation between the two groups (P>0.05), except that the end-tidal carbon dioxide partial pressure (P_ETCO₂) at the time of extubation in group H was significantly higher than group C [(52.9±9.4) mmHg vs (48.9±3.1) mmHg (1 mmHg=0.133 kPa), P<0.001]. Conclusion: HFNO combined with early extubation can significantly reduce the incidence of RAE in children undergoing adenoid-tonsillectomy during the emergence from general anesthesia.

Effects of prolonged anesthesia with dexmedetomidine, fentanyl, or remifentanil on the self-renewal of mouse embryonic stem cells

Previous study has indicated that exposure to anesthesia in early development leads to neuro-apoptosis and is followed by long-term cognitive dysfunction. Given that larger numbers of pregnant women currently receive anesthesia during the first trimester, we wanted to mimic this process in vitro using mouse embryonic stem cells (mESCs) and to explore how different anesthetics affect the self-renewal of mESCs. In the present study, mESCs were exposed to dexmedetomidine, fentanyl, or remifentanil at clinical concentrations for 48 h. The mESCs were then analyzed for cell proliferation and apoptosis. Furthermore, we used flow cytometry to analyze the cell cycle and quantitative real-time polymerase chain reaction to detect the gene expression during the cell cycle as well as the relevant stemness markers. We found that prolonged anesthesia with dexmedetomidine or fentanyl significantly inhibited mESC proliferation, with fewer cell numbers as well as decreased expression of cyclin B and cyclin E mRNA compared to that in the control group; meanwhile, p21 and RB2 gene expression was increased. Additionally, increases or decreases in the proportion of cells in the G1 and S phases, respectively, were observed in the dexmedetomidine- and fentanyl-treated groups. These anesthetics also repressed the gene expression of mESC stemness makers such as Oct4 and Sox2. However, remifentanil seemed to have no significant influence on the self-renewal of mESCs. These results demonstrated that prolonged anesthesia with dexmedetomidine or fentanyl, but not remifentanil, inhibited mESC proliferation by blocking the G1 to S transition, and repressed the maintenance of mESC stemness.