The acute care burden of asthma in children was profoundly reduced during the COVID-19 pandemic: A multi-centre Canadian retrospective study.

Objectives: Asthma is a chronic lung condition that can be exacerbated when triggered by viruses. Pandemic public health restrictions aimed to reduce COVID-19 transmission indirectly effected other circulating viruses. This study assessed the impact of the pandemic and associated public health measures on acute paediatric asthma across four tertiary sites in three Canadian provinces. We queried whether pandemic-related changes would impair preventive care and delay presentation to care, increasing asthma exacerbation severity. Methods: This retrospective study compared the frequency of acute care access and severity of presentation to emergency departments (ED) for acute asthma to four tertiary care children's hospitals during the COVID-19 pandemic (from March 17, 2020 to June 30, 2021) to a pre-lockdown control period (July 1, 2018 to March 16, 2020). Data was subjected to interrupted time series and Chi-square analysis. Results: Our study included 26,316 acute asthma visits to ED. Sites experienced a 63% to 89% reduction in acute asthma visits during the pandemic, compared with pre-lockdown controls, and a 17% to 85% reduction in asthma, that is out of proportion as a fraction of all-cause ED visits. For asthma, there was no difference in severity measured by rate of ward admission or rate of Paediatric Intensive Care Unit (PICU) admission. Conclusions: Public health measures appear to have resulted in a specific protective association on acute asthma with reduced acute care utilization over and above the reduction in all-cause presentations, without an increase in severity upon presentation. Our study indicates an importance to antiviral public health and engineering strategies to reduce viral transmission and thereby asthma morbidity.

Understanding the use and outcomes of high-flow nasal cannula among infants admitted to Canadian hospitals with bronchiolitis (CanFLO): a protocol for a multicentre, retrospective cohort study.

INTRODUCTION: Bronchiolitis is the most common viral lower respiratory tract infection in children under 2 years of age. Respiratory support with high-flow nasal cannula (HFNC) is increasingly used in this patient population with limited understanding of the patients most likely to benefit and considerable practice variability of use. This study aims to understand the factors associated with failure of HFNC support among patients with bronchiolitis and to describe the current practice variations of HFNC use in patients with bronchiolitis in Canadian hospitals including fluid management and parameters to initiate, escalate and discontinue HFNC support. METHODS AND ANALYSIS: This is a multicentre retrospective cohort study including hospitalised patients aged 0-24 months with bronchiolitis requiring support with HFNC between January 2017 and December 2021. Clinical data will be collected from patient medical records from Canadian hospitals (n=12), including academic and community centres. HFNC failure will be defined as the need for escalation to non-invasive or invasive mechanical ventilation. Factors associated with HFNC failure will be analysed using logistic regression. Descriptive statistics will be used to describe practice variations of HFNC utilisation and management. ETHICS AND DISSEMINATION: Approval from the Research Ethics Boards (REBs) has been obtained for each participating study site prior to onset of data collection including Clinical Trials Ontario for all Ontario hospital sites and REBs from British Columbia Children's Hospital, Stollery Children's Hospital, Montreal Children's Hospital and CHU Sainte-Justine. Study results will be disseminated through presentation at national/international conferences and publication in high-impact, peer-reviewed journals.

Nasal Brushing Sampling and Processing using Digital High Speed Ciliary Videomicroscopy - Adaptation for the COVID-19 Pandemic.

Primary Ciliary Dyskinesia (PCD) is a genetic motile ciliopathy, leading to significant otosinopulmonary disease. PCD diagnosis is often missed or delayed due to challenges with different diagnostic modalities. Ciliary videomicroscopy, using Digital High-Speed Videomicroscopy (DHSV), one of the diagnostic tools for PCD, is considered the optimal method to perform ciliary functional analysis (CFA), comprising of ciliary beat frequency (CBF) and beat pattern (CBP) analysis. However, DHSV lacks standardized, published operating procedure for processing and analyzing samples. It also uses living respiratory epithelium, a significant infection control issue during the COVID-19 pandemic. To continue providing a diagnostic service during this health crisis, the ciliary videomicroscopy protocol has been adapted to include adequate infection control measures. Here, we describe a revised protocol for sampling and laboratory processing of ciliated respiratory samples, highlighting adaptations made to comply with COVID-19 infection control measures. Representative results of CFA from nasal brushing samples obtained from 16 healthy subjects, processed and analyzed according to this protocol, are described. We also illustrate the importance of obtaining and processing optimal quality epithelial ciliated strips, as samples not meeting quality selection criteria do now allow for CFA, potentially decreasing the diagnostic reliability and the efficiency of this technique.

Ciliary functional analysis: Beating a path towards standardization.

Primary ciliary dyskinesia is an inherited disorder in which respiratory cilia are stationary, or beat in a slow or dyskinetic manner, leading to impaired mucociliary clearance and significant sinopulmonary disease. One diagnostic test is ciliary functional analysis using digital high-speed video microscopy (DHSV), which allows real-time analysis of complete ciliary function, comprising ciliary beat frequency (CBF) and ciliary beat pattern (CBP). However, DHSV lacks standardization. In this paper, the current knowledge of DHSV ciliary functional analysis is presented, and recommendations given for a standardized protocol for ciliary sample collection and processing. A proposal is presented for a quantitative and qualitative CBP evaluation system, to be used to develop international consensus agreement, and future DHSV research areas are identified.

Variation of Ciliary Beat Pattern in Three Different Beating Planes in Healthy Subjects.

BACKGROUND: Digital high-speed video microscopy (DHSV) allows analysis of ciliary beat frequency (CBF) and ciliary beat pattern (CBP) of respiratory cilia in three planes. Normal reference data use a sideways edge to evaluate ciliary dyskinesia and calculate CBF using the time needed for a cilium to complete 10 beat cycles. Variability in CBF within the respiratory epithelium has been described, but data concerning variation of CBP is limited in healthy epithelium. This study aimed to document variability of CBP in normal samples, to compare ciliary function in three profiles, and to compare CBF calculated over five or 10 beat cycles. METHODS: Nasal brushing samples from 13 healthy subjects were recorded using DHSV in three profiles. CBP and CBF over a 10-beat cycle were evaluated in all profiles, and CBF was reevaluated over five-beat cycles in the sideways edges. RESULTS: A uniform CBP was seen in 82.1% of edges. In the sideways profile, uniformity within the edge was lower (uniform normal CBP, 69.1% [sideways profile]; 97.1% [toward the observer], 92.0% [from above]), and dyskinesia was higher. Interobserver agreement for dyskinesia was poor. CBF was not different between profiles (P = .8097) or between 10 and five beat cycles (P = .1126). CONCLUSIONS: Our study demonstrates a lack of uniformity and consistency in manual CBP analysis of samples from healthy subjects, emphasizing the risk of automated CBP analysis in limited regions of interest and of single and limited manual CBP analysis. The toward the observer and from above profiles may be used to calculate CBF but may be less sensitive for evaluation of ciliary dyskinesia and CBP. CBF can be measured reliably by evaluation of only five-beat cycles.

Long-term survival and outcome in children admitted to kilifi district hospital with convulsive status epilepticus.

Objectives. The incidence of convulsive status epilepticus (CSE) is high in Africa but the long-term outcome is unknown. We examined the neurocognitive outcome and survival of children treated for CSE in a Kenyan hospital 3 to 4 years after discharge. Methods. The frequency and nature of neurological deficits among this group of children were determined and compared to a control group. The children were screened with the Ten Questions Questionnaire for neurodevelopmental impairment if alive and those that screened positive were invited for further assessment to determine the pattern and extent of their impairment. A verbal autopsy was performed to determine the cause of death in those that died. Results. In the 119 cases followed-up, 9 (8%) died after discharge, with the majority having seizures during their fatal illness. The 110 survivors (median age 5 years) had significantly more neurological impairments on the screening compared to 282 controls (34/110 (30.9%) versus 11/282 (3.9%), OR = 11.0, 95% CI 5.3-22.8). Fifteen percent of the cases had active epilepsy. Conclusions. This study demonstrates the considerable burden of CSE in African children. Strategies to manage children with CSE that are acceptable to the community need to be explored to improve the longer-term outcome.

Incidence and outcome of convulsive status epilepticus in Kenyan children: a cohort study.

BACKGROUND: Convulsive status epilepticus (CSE) is the most common neurological emergency in childhood and is often associated with fever. In sub-Saharan Africa, the high incidence of febrile illnesses might influence the incidence and outcome of CSE. We aimed to provide data on the incidence, causes, and outcomes of childhood CSE in this region. METHODS: Between March, 2006, and June, 2006, we studied all children who had been admitted with CSE to a Kenyan rural district hospital in 2002 and 2003. Confirmed CSE had been observed directly; probable CSE was inferred from convulsions on arrival, requirement for phenobarbital or phenytoin, or coma with a recent history of seizures. We estimated the incidence with linked demographic surveillance, and risk factors for death and neurological sequelae were analysed by multivariable analysis. FINDINGS: Of 388 episodes of CSE, 155 (40%) were confirmed CSE and 274 (71%) were caused by an infection. The incidence of confirmed CSE was 35 (95% CI 27-46) per 100,000 children per year overall, and was 52 (21-107) and 85 (62-114) per 100,000 per year in children aged 1-11 months and 12-59 months, respectively. The incidence of all CSE was 268 (188-371) and 227 (189-272) per 100,000 per year in these age-groups. 59 (15%) children died in hospital, 81 (21%) died during long-term follow-up, and 46 (12%) developed neurological sequelae. Mortality of children with confirmed CSE while in hospital was associated with bacterial meningitis (adjusted relative risk [RR]=2.6; 95% CI 1.4-4.9) and focal onset seizures (adjusted RR=2.4; 1.1-5.4), whereas neurological sequelae were associated with hypoglycaemia (adjusted RR=3.5; 1.8-7.1) and age less than 12 months (adjusted RR=2.5; 1.2-5.1). INTERPRETATION: Prevention of infections and appropriate early management of seizures might reduce the incidence and improve the outcome of CSE in children in sub-Saharan Africa.

Population pharmacokinetics of a single daily intramuscular dose of gentamicin in children with severe malnutrition.

OBJECTIVES: The World Health Organization recommends that all children admitted with severe malnutrition should routinely receive parenteral ampicillin and gentamicin; despite this, mortality remains high. Since this population group is at risk of altered volume of distribution, we aimed to study the population pharmacokinetics of once daily gentamicin (7.5 mg/kg) in children with severe malnutrition and to evaluate clinical factors affecting pharmacokinetic parameters. METHODS: Thirty-four children aged 0.5-10 years were studied. One hundred and thirty-two gentamicin concentrations (median of four per patient), drawn 0.4-24.6 h after administration of the intramuscular dose, were analysed. The data were fitted by a two-compartment model using the population package NONMEM. RESULTS: Gentamicin was rapidly absorbed and all concentrations measured within the first 2 h after administration were > 8 mg/L (indicating that satisfactory peak concentrations were achieved). Ninety-eight percent of samples measured more than 20 h after the dose were < 1 mg/L. The best model included weight, and it was found that high base deficit, high creatinine concentration and low temperature (all markers of hypovolaemic shock) reduced clearance (CL/F). Weight influenced volume of the central (V1/F) and peripheral (V2/F) compartments, and high base deficit reduced V2/F and intercompartmental CL (Q/F). Interindividual variability in CL was 26%, in V1/F 33% and in V2/F and Q/F was 52%. Individual estimates of CL/F ranged from 0.02 to 0.16 (median 0.10) L/h/kg and those of Vss/F from 0.26 to 1.31 (median 0.67) L/kg. Initial half-lives had a median of 1.4 h and elimination half-lives and a median of 14.9 h. Excessive concentrations were observed in one patient who had signs of renal impairment and shock. CONCLUSIONS: Although a daily dose of 7.5 mg/kg achieves satisfactory gentamicin concentrations in the majority of patients, patients with renal impairment and shock may be at risk of accumulation with 24 hourly dosing. Further studies of gentamicin pharmacokinetics in this group are now needed to inform future international guideline recommendations.