Incidence and predictors of respiratory adverse events in children undergoing procedural sedation with intramuscular ketamine in a paediatric emergency department

INTRODUCTION@#Although ketamine is one of the commonest medications used in procedural sedation of children, to our knowledge, there is currently no published report on predictors of respiratory adverse events during ketamine sedation in Asian children. We aimed to determine the incidence of and factors associated with respiratory adverse events in children undergoing procedural sedation with intramuscular (IM) ketamine in a paediatric emergency department (ED) in Singapore.@*METHODS@#A retrospective analysis was conducted of all children who underwent procedural sedation with IM ketamine in the paediatric ED between 1 April 2013 and 31 October 2017. Demographics and epidemiological data, including any adverse events and interventions, were extracted electronically from the prospective paediatric sedation database. The site of procedure was determined through reviewing medical records. Descriptive statistics were used for incidence and baseline characteristics. Univariate and multivariate logistic regression analyses were performed to determine significant predictors.@*RESULTS@#Among 5,476 children, 102 (1.9%) developed respiratory adverse events. None required intubation or cardiopulmonary resuscitation. Only one required bag-valve-mask ventilation. The incidence rate was higher in children aged less than three years, at 3.6% compared to 1.0% in older children (odds ratio [OR] 3.524, 95% confidence interval [CI] 2.354-5.276; p < 0.001). Higher initial ketamine dose (adjusted OR 2.061, 95% CI 1.371-3.100; p = 0.001) and the type of procedure (adjusted OR 0.190 (95% CI 0.038-0.953; p = 0.044) were significant independent predictors.@*CONCLUSION@#The overall incidence of respiratory adverse events was 1.9%. Age, initial dose of IM ketamine and type of procedure were significant predictors.

A booster dose enhances immunogenicity of the COVID-19 vaccine candidate ChAdOx1 nCoV-19 in aged mice

The spread of SARS-CoV-2 has caused a global pandemic that has affected almost every aspect of human life. The development of an effective COVID-19 vaccine could limit the morbidity and mortality caused by infection, and may enable the relaxation of social distancing measures. Age is one of the most significant risk factors for poor health outcomes after SARS-CoV-2 infection, therefore it is desirable that any new vaccine candidates should elicit a robust immune response in older adults. Here, we test the immunogenicity of the adenoviral vectored vaccine ChAdOx1 nCoV-19 (AZD-1222) in aged mice. We find that a single dose of this vaccine induces cellular and humoral immunity in aged mice, but at a reduced magnitude than in younger adult mice. Furthermore, we report that a second dose enhances the immune response to this vaccine in aged mice, indicating that a primeboost strategy may be a rational approach to enhance immunogenicity in older persons.