Objective To improve the orotracheal intubation verifying technique and reduce the complication of backflow in rat experiment.Methods A new position evaluation of anti-backflow device was designed and made of safety IV catheter and closed IV catheter system.60 adult male Sprague Dawley rats 216±20 g were randomly assigned to two groups: group A (n=40) for verifying placement, group B (n=20) for anti-backflow test.Group A was further divided into group A1 using self-designed positioning device, group A2 using aerosol, group A3 taking cotton fiber for positioning judgment.The group B was divided into two subgroups, B1 and B2, counting escaped bubbles as a means of positioning observation, the difference is that group B1 using frustum of a cone shape anti-backflow device, while the group B2 using common airway tube.Routine endotracheal intubation was performed to observe and record the time of positioning, the location of exhalation phase, and the length of inspiratory phase countercurrent water column.The group A1 further performed tracheotomy under direct vision clearly to confirm the anatomic positioning status.Results During the exhalation cycle,three or more bubbles were observed to escape continuously, indicating that the intubation tube was properly placed and open in the airway.Positioning time: It took 1.75±1.02 respiratory cycles in group A1,3.30±0.95 respiratory cycles in group A2 and 4.10±0.99 respiratory cycles in group A3 to complete the assessment the positioning status.There was no statistically significant difference between groups A2 and A3 (P> 0.05).The time needed for group A1 was significantly shorter than that of groups A2 and A3 (P < 0.01).The longest countercurrent water column length in group B1 was 3.23±0.53 cm, and 8.48±1.01 cm in the group B2.Conclusions The new designed anti-backflow positioning evaluation device is a simple and convenient appliance to evaluate the location of orotracheal intubation in rat experiment.It can effectively improve the positioning efficiency and has practical application value.

Objective:To explore the prognostic impact of different intracranial radiotherapy modalities in patients with a limited number (≤10) of brain metastases from small cell lung cancer (SCLC-BM).Methods:The data of 143 cases with SCLC-BM that received intracranial radiotherapy at the First Affiliated Hospital of Bengbu Medical University in 2019-2022 were analyzed. The patients were grouped by radiotherapy modalities: whole brain radiotherapy (WBRT, 58 cases), WBRT combined with simultaneous integrated boost (WBRT+ SIB, 53 cases), and WBRT combined with sequential integrated boost (WBRT+ SEB, 32 cases). The overall survival (OS) and intracranial progression-free survival (IPFS) were calculated using the Kaplan-Meier method, and the Cox proportional hazard model was used for prognostic analysis.Results:In the whole group, the median OS and IPFS were 11.9 and 9.9 months, and the 1-, 2-, and 3-year survival rates were 49.7%, 15.3%, and 2.9%, respectively. The difference in OS among patients in the WBRT+ SIB, WBRT+ SEB, and WBRT groups was not significant (median OS: 13.0 months vs. 12.5 months vs. 11.2 months, P>0.05). The WBRT+ SIB and WBRT+ SEB groups were preferred over the WBRT group in terms of IPFS (median IPFS: 11.7 months vs. 10.4 months vs. 8.1 months, χ2=21.69, P<0.001). For patients with few brain metastases (≤3) analyzed separately, the WBRT+ SIB and WBRT+ SEB groups were preferred over the WBRT group in terms of OS and IPFS (median OS: 14.4 months vs. 13.7 months vs. 11.5 months, χ2=8.72, P=0.013; median IPFS: 12.6 months vs. 10.4 months vs. 8.9 months, χ2=12.37, P=0.002). Evaluation of the central nervous system as well as hematological acute radiological reactions reaching grade 2 and above showed no significant differences among the three groups ( P>0.05). Multivariate analysis showed that subsequent chemotherapy, targeted therapy, and immunotherapy were common independent influencing factors for patients′ OS and IPFS. Body mass index (BMI) level was an independent influencing factor for patients′ OS, and the number of brain metastases, lymph node metastasis, and radiotherapy modality were independent influencing factors for patients′ IPFS. Conclusions:BMI level and subsequent treatment (chemotherapy, targeted therapy, and immunotherapy) are independent influencing factors for patients' prognosis. WBRT+ SIB and WBRT+ SEB modalities are associated with increased IPFS.