Objective To investigate the effect of non humidification,200 ml and 100 ml distilled water humidification on oxygen output flow of Venturi mask,and to provide basis and reference for clinical application of Venturi mask oxygen therapy.Methods In August 2024,the output end of an oxygen flow meter installed with a water humidification device was connected with a Venturi mask and an external flow sensor of a ventilator in turn.The oxygen output flow of the Venturi mask was measured under the conditions of no humidification,200 ml distilled water humidification and 100 ml distilled water humidification,respectively,at oxygen concentration set of 24％,26％,28％,31％,35％,40％and 50％.The measured output flow data of the 3 groups were statistically analyzed.Results The oxygen output flow of the Venturi mask ranged from 7.6 to 45.6 L/min,and the input flow was 3 L/min or 6 L/min.The higher the oxygen concentration,the lower the oxygen output flow of the Venturi mask.Under the same oxygen concentration,the average output flow of 200 ml distilled water humidification group was lower than that of 100 ml distilled water humidification group and non humidification group(P＜0.05).When the oxygen concentration was set at 24％,26％,31％and 35％,the oxygen output flow of non humidification group was higher than that of 100 ml distilled water humidification group(P＜0.05).At 40％and 50％oxygen concentration,the oxygen output flow of 100 ml distilled water humidification group was higher than that of non humidification group(P＜0.05).Conclusion The overall output flow of the Venturi mask is low,and the input flow is the same.The higher the oxygen concentration,the lower the output flow.The humidification of 200ml distilled water may lead to insufficient oxygen flow in patients,while the humidification of 100ml distilled water has little effect on the output flow of Venturi mask.

Objective To investigate the effect of non humidification,200 ml and 100 ml distilled water humidification on oxygen output flow of Venturi mask,and to provide basis and reference for clinical application of Venturi mask oxygen therapy.Methods In August 2024,the output end of an oxygen flow meter installed with a water humidification device was connected with a Venturi mask and an external flow sensor of a ventilator in turn.The oxygen output flow of the Venturi mask was measured under the conditions of no humidification,200 ml distilled water humidification and 100 ml distilled water humidification,respectively,at oxygen concentration set of 24％,26％,28％,31％,35％,40％and 50％.The measured output flow data of the 3 groups were statistically analyzed.Results The oxygen output flow of the Venturi mask ranged from 7.6 to 45.6 L/min,and the input flow was 3 L/min or 6 L/min.The higher the oxygen concentration,the lower the oxygen output flow of the Venturi mask.Under the same oxygen concentration,the average output flow of 200 ml distilled water humidification group was lower than that of 100 ml distilled water humidification group and non humidification group(P＜0.05).When the oxygen concentration was set at 24％,26％,31％and 35％,the oxygen output flow of non humidification group was higher than that of 100 ml distilled water humidification group(P＜0.05).At 40％and 50％oxygen concentration,the oxygen output flow of 100 ml distilled water humidification group was higher than that of non humidification group(P＜0.05).Conclusion The overall output flow of the Venturi mask is low,and the input flow is the same.The higher the oxygen concentration,the lower the output flow.The humidification of 200ml distilled water may lead to insufficient oxygen flow in patients,while the humidification of 100ml distilled water has little effect on the output flow of Venturi mask.

December 2019 witnessed the outbreak of COVID-19 in Wuhan and spread of the epidemic across the country. As a provincial designated hospital for critical patients, the First Affiliated Hospital of Zhejiang University responded rapidly since then by advocating the four-concentration principles, namely " concentrating patients, experts, resources and treatment" . In its rescue of critical patients, the hospital formulated comprehensive emergency plans, optimized hospital-wide resources, effectively arranged rescue spacing, established medical echelons, and implemented multi-disciplinary strategy. These efforts ensured efficient rescue and treatment, achieving a cure rate up to 98.7% of such patients, with no deaths.

Objective To evaluate the apical sealing ability of iRoot SP root canal sealer in oval-root canal. Methods After root canals were instrumented by Mtwo, 28 premolars with oval-root canal were randomly divided into 2 groups, 14 teeth in each. The root canals were obturated with AH Plus (group A) and iRoot SP (group B) by modified continuous wave condensation technique. The apical leakage was evaluated by dye penetration method and transparent teeth technique. Results Mean depth of leakage was (0.92 ± 0.26) mm for group A and (0.84 ± 0.40) mm for group B. There was no significant difference between the two groups (t=0.506, P > 0.05). Conclusion The apical sealing ability of iRoot SP is equivalent to AH Plus in oval-root canal.