Objective To evaluate the accuracy of ultrasonographic measurement of the transverse diameter of the cricoid cartilage in selecting the cuffed endotracheal tube (ETT) size for pediatric patients.Methods A total of 120 pediatric patients of both sexes,of American Society of Anesthesiologists physical status Ⅰ or Ⅱ,aged 1 month-6 yr,with body mass index of 10.9-31.2 kg/m2,undergoing endotracheal intubation and general anesthesia,were divided into group A and group B,with 60 pediatric patients in each group.The pediatric patients were intubated with a cuffed ETT in two groups.The ETT size was selected based on the transverse diameter of the cricoid cartilage measured by ultrasonography in group A.The ETT size was selected according to the age-based formula in group B.A tracheal leak was detected after intubation to determine whether or not the ETT size selected was appropriate.ETTs were replaced when the actually selected ones were not appropriate,and the number of replacement was recorded.The development of intubation-related complications was also recorded.Results The accurate rate of cuffed ETT size selected at the first time was 95％ in group A,and it was significantly higher than that in group B (60％) (P＜ 0.05).There was no significant difference in the incidence of intubation-related complications between the two groups (P＞0.05).Conclusion Uhrasonographic measurement of the transverse diameter of the cricoid cartilage produces higher accuracy in selecting the cuffed ETT size for pediatric patients and is worthy of clinical application.

Objective:To explore the effects of external diaphragm electrical stimulation on the diaphragm thickness and function in mechanically ventilated children.Methods:A randomized controlled trial was conducted in children who were admitted to PICU at Children′s Hospital of Fudan University and received mechanical ventilation between June 2021 and April 2022.The control group was given the routine treatment of mechanical ventilation, and the intervention group was given external diaphragm electrical stimulation in the early stage of mechanical ventilation in addition to routine treatment.Diaphragm thickness was continuously measured by bedside ultrasound every day for one week after mechanical ventilation, and the changing trend of diaphragm thickness was observed, and the diaphragmatic thickening fraction (DTf) and the incidence of ventilator-induced diaphragmtic dysfunction(VIDD) were calculated at the same time.Results:A total of 32 valid samples were included, including 15 cases in intervention group (10 males) and 17 cases in control group (11 males). The median age of the patients was 33 (10, 77) months, and the median duration of mechanical ventilation was 12 (8, 21) days.The reasons for mechanical ventilation in children included respiratory insufficiency in ten cases, brain dysfunction in ten cases, heart failure in eight cases, and postoperative surgery in four cases.The diaphragm end-expiratory thickness (DTe) in intervention group and the control group showed a gradually decreasing trend from the 1st day to the 7th day.The left thickness was reduced by 11% on the 7th day compared to 1st day in intervention group, which was reduced by 18% in control group; the average daily DTe was reduced by 2% per day in intervention group and by 3% per day in control group.The trends on the right and left were similar.The DTe thickness in the intervention group was greater than that in control group, among which, the mean DTe thickness in the left side of the intervention group on the 7th day was (0.110 7±0.023 7)cm, which was greater than that in control group (0.093 5±0.016 9)cm, and the difference was statistically significant ( t=-2.372, P<0.05); On the second day, the mean DTe thickness on the right side in the intervention group was (0.1267±0.0277) cm, which was greater than that in control group (0.104 7±0.018 1)cm, and the difference was statistically significant ( t=-2.688, P<0.05). DTf in the intervention group was lower than that in control group at 7th day, but the difference was not statistically significant(left DTf: adjusted mean difference was -0.117, P=0.088; right DTf: adjusted mean difference was -0.065, P=0.277). The incidence of VIDD in the intervention group was lower than that in control group(33.3% vs.41.2%), but the difference was not statistically significant ( χ2=0.005, P=0.946). Conclusion:External diaphragmatic electrical stimulation may be helpful for alleviating diaphragmatic atrophy in mechanically ventilated children.However, whether the improvement of diaphragm atrophy is beneficial to clinical outcome still needs further study.