Lettie C. Leung

Ambulatory blood pressure before and after adenotonsillectomy in children with obstructive sleep apnea.

INTRODUCTION Hypertension is found to be associated with obstructive sleep apnea (OSA) in both children and adults. But data on the effect of blood pressure after adenotonsillectomy (AT) for children with OSA are limited and controversial. OBJECTIVE To assess the impact of AT on different parameters of 24-h ambulatory blood pressure monitoring in children with OSA. METHODS We retrospectively reviewed records of OSA children who had undergone AT and a repeated sleep polysomnography after AT from 2001 to 2008. RESULTS Forty-four children were identified and included in the analysis. The mean apnea-hypopnea index (AHI) dropped from 14.14+/-15.9 to 3.3+/-7.1. (p<0.001). Twenty (45%) were cured of OSA. After AT, the diastolic BP load decreased significantly. Six out of eight (75%) hypertensive children became normotensive after surgery. For the pre-AT hypertensive group, both systolic and diastolic blood pressure decreased significantly during sleep after AT. However, eight children who were normotensive before AT became hypertensive after AT. These 10 post-AT hypertensive patients were more likely to have post-AT AHI>1 than the post-AT normotensive group, although the difference did not reach statistical significance. CONCLUSION In the current cohort of OSA children, 44% were cured of OSA and a significant decrease in overall diastolic blood pressure load in 24-h ambulatory blood pressure was achieved after adenotonsillectomy for children with OSA. But hypertension may persist or even occur in those previously normotensive children despite the improvement in AHI. Persistence of OSA may be a risk factor and further study is required. Cure of OSA should not be assumed after AT and follow-up PSG should be performed together with 24-h ambulatory blood pressure monitoring. In light of the current findings, long term study of the blood pressure is warranted for children with OSA.

Prevalence and risk factors for hypertension in Hong Kong Chinese adolescents: waist circumference predicts hypertension, exercise decreases risk

Purpose To determine the prevalence, risk factors for and patterns of hypertension in Chinese adolescents based on a territory-wide school based screening programme in Hong Kong. Methods Cross-sectional anthropometric and oscillometric blood pressure (BP) measurements and lifestyle information were obtained as part of a growth survey of students from randomly selected secondary schools in Hong Kong. Those with blood pressure ≥95th centile were screened a second or third time. Hypertension is defined as elevated blood pressure on three separate occasions. The independent effects of age, sex, body mass index, high waist circumference (≥85th centile), sleep duration, family history of hypertension and frequency of exercise on hypertension were explored by multivariate analysis. Results Among the 6193 students screened, the prevalence of elevated blood pressure on the first, second and third screens was 9.54%, 2.77% and 1.44% respectively. Hypertension was more likely to be systolic. High waist circumference (≥85th centile) was independently associated with a higher risk of hypertension (adjusted OR 2.4), while exercising twice or more per week was protective (adjusted OR 0.28). Conclusions The prevalence of hypertension in Hong Kong Chinese adolescents is 1.44%. The current study shows high waist circumference is a predictor of hypertension in adolescents, while increased physical activity is a protective factor. Incorporating waist circumference into screening protocols may increase the sensitivity of cardiovascular risk stratification. Healthcare providers should be strong advocates helping to prevent obesity and promote physical activity in adolescents and children.

Evaluating different imaging strategies in children after first febrile urinary tract infection

We conducted a retrospective multicenter review to estimate the prevalence of urological abnormalities in Chinese children with first febrile urinary tract infection (UTI) and to evaluate the selective imaging strategy recommended by the NICE guideline for detecting underlying abnormalities. Atypical UTI was defined as in the NICE UTI guideline. Overall, 576 boys and 244 girls aged below 24 months were reviewed. All underwent ultrasound (US) and micturating cystourethrogram (MCUG) and 612 underwent DMSA scans. US was abnormal in 73 (8.9%) and vesicoureteral reflux was shown in 195 patients (23.8%). A total of 126 patients were considered to have remediable urological abnormalities requiring additional surgical or medical interventions. The NICE guideline yielded excellent negative predictive values (NPV) of 100–94.4% in girls but 91% in boys. If all boys underwent US and DMSA and only those with atypical UTI or abnormal US or DMSA proceeded to MCUG, then the NPV increased to 95.2% and 97.4% for boys aged below and above 6 months, respectively. These revised strategies would substantially save invasive studies—DMSA and MCUG in 27 and 74% of girls aged below and above 6 months, respectively, or MCUG in 23 and 59% of boys aged below and above 6 months, respectively.

Non-contact infrared thermometry temperature measurement for screening fever in children

Abstract Background: During the SARS epidemic, mass fever screening at border control points and public hospitals was done by measuring forehead temperature by non-contact infrared thermometry. However, its accuracy is not well documented. Methods: We evaluated the agreement of non-contact infrared forehead temperature (NIFT) measurement by comparing NIFT readings with tympanic temperatures taken in children (1 mth to 18 yrs) admitted to the general paediatric wards of Kwong Wah Hospital, Hong Kong. Results: A total of 567 patients were recruited and 1000 pairs of readings were obtained. The incidence of fever, defined as tympanic temperature (in rectal model) >38°C (100.4°F), was 12.3%. The mean difference between NIFT and tympanic temperature was 2.34°C (4.21°F) and the 95% limit of agreement between NIFT and tympanic temperature was 0.26–4.42°C (0.47–7.96°F). NIFT was significantly lower than tympanic temperature readings. The optimal cut-off point of NIFT derived from the receiver-operator characteristics curve for fever definition was 35.1°C (95.2°F). The sensitivity, specificity, positive predictive value and negative predictive value of this cut-off point for fever screening were 89.4%, 75.4%, 33.7% and 98.1%, respectively. Conclusions: NIFT measurement has a reasonable accuracy in detecting tympanic fever in children. However, one should be aware of the high false-positive rate of fever screening using NIFT.

Oscillometric 24-h ambulatory blood pressure reference values in Hong Kong Chinese children and adolescents

Objectives: We aimed to establish community-based normal reference values of 24-h ambulatory blood pressure monitoring (ABPM) for Chinese children and adolescents. Furthermore, we investigated how excluding overweight children affects BP percentiles and compared them with German references. Methods: In this territory-wide cross-sectional prospective cohort study, 1445 Hong Kong Chinese children and adolescents aged 8–17 years with body height between 119 and 185 cm were recruited. Their ABPM assessment was performed using validated arm oscillometric recorders (A&D TM-2430) and complied with American Heart Associations recommendations. The reference tables were constructed using the LMS method to normalize skewed distribution of ABP data to sex and age or height. Results: The ambulatory BP was higher among boys and the difference between boys and girls progressively widened with age. An increasing trend in daytime and night-time SBP and DBP with age and height was observed in both sexes. The age-specific and sex-specific 95th percentiles from nonoverweight children (n = 1147; 79%) were lower than the whole cohort by up to 2.5 and 1 mmHg for SBP and DBP, respectively. In comparison, our overall and nonoverweight reference standards were generally higher than corresponding German references. Conclusion: The study provides ambulatory BP standards for Chinese children, with sex-related age-specific and height-specific percentiles. Further longitudinal studies are required for investigating its clinical utility in Chinese.

A randomized controlled trial of azithromycin and amoxycillin/clavulanate in the management of subacute childhood rhinosinusitis.

Objective: Subacute childhood rhinosinusitis is a disorder commonly seen in children with allergic rhinitis. Antibiotics have been recommended as a major component of the treatment regime. The objective of the present study was to compare the effectiveness of a 3‐day course of azithromycin and a 2‐week course of amoxycillin/clavulanate in the treatment of subacute childhood rhinosinusitis.

Association between waist circumference and childhood‐masked hypertension: A community‐based study

The aim of this study is to determine the association between waist circumference (WC) and childhood‐masked hypertension.

Airway Obstruction in Premature Newborns: A Missing Link

providers who are very familiar with this practice parameter use IVF 75% of the time, and those who are less familiar use IVF 90% of the time for moderately dehydrated children. The fact that only 15% of these children were unable to tolerate ORT demonstrates that we can potentially reduce the amount of IVF administered to children by 50%. We limited the study enrollment period until 8 pm for practical purposes so that the 4-hour study would be completed before midnight (when our research staff and attending coverage was more limited). It is true, however, that ORT requires a cooperative patient and parent to succeed. Additional study of the ability of patients and families to perform ORT in the middle of the night is warranted. Furthermore, Dr Reid raises the issue of intention-to-treat versus treatment-received analysis. Intention-to-treat analysis is the favored approach and is the main result presented in our trial because it avoids bias associated with nonrandom loss of participants. However, a simultaneous presentation of the treatmentreceived analysis is appropriate, because it describes what happened to the patients who were compliant with the therapy.4 In our trial, 3 patients in the ORT group dropped out because the parents truly didn’t want ORT, and 3 patients in the IVF group did not receive the IVF. It is these patients who were excluded in the treatment-received approach. We were very careful to clearly state when a result was based on the treatment-received analysis. Dr Reid states that what matters to physicians is the intention-to-treat approach. We believe that a thorough evaluation of all data is critical to practitioners making treatment decisions. In the intention-to-treat approach, there was an 18% greater hospitalization rate for patients who received IVF, although this finding was just short of our a priori definition of statistical significance. In the treatment-received analysis, this finding was significant.