Daniel K. Ng

Use of intramuscular ketamine for endoscopy sedation in children.

Abstract Objective : To report the experience of the use of intramuscular (IM) ketamine for endoscopy sedation in children.

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.

An update on childhood snoring

Habitual snoring or daily snoring is a symptom of sleep‐disordered breathing (SDB) in children and it is reported in about 10% of children. SDB includes primary snoring, upper airway resistance syndrome (UARS), obstructive hypoventilation syndrome and obstructive sleep apnea syndrome (OSAS). Classification of SDB in a particular snoring child requires an overnight polysomnography (PSG). Manual scoring of PSG is mandatory in children. Risk factors for SDB include allergic rhinitis, passive smoking, obesity, dysmorphic syndromes and neuromuscular disorders. Conclusion: Treatment includes general measures like treatment of allergic rhinitis, weight reduction in obese children, and avoidance of sleep deprivation. Specific measures include removal of adenoid and tonsils. Complications of SDB include neurocognitive impairment, hypertension and failure to thrive.

Heart rate variability in childhood obstructive sleep apnea.

The identification of patients with obstructive sleep apnea (OSA) is important because of morbidities associated with OSA. A previous adult study demonstrated the use of heart rate variability (HRV) as a tool to identify patients with moderate to severe OSA. Either a reduction in time parameters or an increase in LF/HF ratio was seen at overnight or 24‐hr studies suggestive of increased sympathetic modulation. To study the feasibility of daytime HRV as a screening tool, a short‐term recording of HRV is studied. Since it was shown in adult study that increased normalized LF, decreased normalized HF and increased LF/HF ratio could be detectable during supine rest at daytime awake period, the authors hypothesize that the differences are also detectable in children. Children who underwent sleep polysomnography for suspected OSA were recruited. Subjects were classified OSA if apnea‐hypopnea index (AHI) > 1.5/hr and non‐OSA if AHI ≤ 1.5/hr. Continuous 1‐hr electrocardiographic monitoring was recorded in awake children during the day. Parameters from time domain and frequency domain were analyzed. Seventy‐four male and 17 female snoring subjects were included in this study. Fifty‐one (56%) and 40 (44%) of them were classified as “non‐OSA” and “OSA,” respectively. pNN50, a parameter for parasympathetic modulation, was significantly reduced in the OSA group when compared with the non‐OSA group. Using multiple regression, all time domain variables were shown to be decreased in OSA group. Our results suggest that 1‐hr study of HRV may be a feasible tool in identifying children with OSA. Pediatr Pulmonol. 2011; 46:205–210.

Gender difference in snoring and how it changes with age: systematic review and meta-regression.

PurposeThe aim of this study was to study the interactions among age, gender, and snoring across all age groupsMethodsAll cross-sectional study reporting gender-specific prevalence of snoring in general population published from 1966 through July 2008 were included and were meta-analyzed. The sources of heterogeneity among primary studies were studied by meta-regression.ResultsFrom a total of 1,593 citations reviewed, 63 were included in the analysis of snoring. These 63 studies were comprised 104,337 and 110,474, respectively. A combined odds ratio of 1.89 with a 95% confidence interval of 1.75–2.03 for male versus female was found. The heterogeneity was significant with an estimated between-study variance, τ2 being 0.065 and 95% confidence interval of 0.0397–0.0941. Multiple meta-regression showed that age were the significant effect modifier of the relationship between snoring and gender.ConclusionThis study found a consistent male predominance in snoring among the general population, and the heterogeneity in the risk of snoring between two genders can be partly explained by age.

Improvement in quality of life after adenotonsillectomy in a child with Prader Willi syndrome

IntroductionWe report a child with Prader Willi syndrome who developed obstructive sleep apnea (OSA). This patient underwent surgical treatment for OSA. There was improvement not only on her OSA but in her quality of life score as well. This report highlights the need for a comprehensive assessment in the management of patients with Prader Willi syndrome.

Validation of sleep‐related breathing disorder scale in Hong Kong Chinese snoring children

The purpose of this study is to validate the previously‐validated Taiwan Chinese version of Sleep‐Related Breathing Disorder scale (SRBD scale) in Hong Kong Chinese snoring children. SRBD scale is an instrument used for prediction of obstructive sleep apnea syndrome. (OSA) The Chinese version of SRBD scale were previously translated and validated in Taiwan. The same questionnaire were administered in a group of 102 snoring children (mean age: 10.7 and 65 boys) from a sleep laboratory in Hong Kong before their sleep studies. The SRBD scores were then validated against the results from sleep studies. By using the definition of apnea‐hypopnea index larger than 1.5 as OSA, 28 children (27.5%) had polysomnography‐confirmed OSA. The sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of the previously validated cut‐off of SRBD score > 0.33 for OSA were 0.5, 0.55, 1.12, and 0.90, respectively. The area under ROC curve was only 0.58, indicates suboptimal performance of SRBD score in predicting OSA. In summary, our study concluded that the previously reported Chinese SRBD scale is not accurate in identifying presence of OSA in Hong Kong Chinese snoring children. Pediatr Pulmonol. 2012. 47:795–800.

Maternally inherited Leigh syndrome: an unusual cause of infantile apnea.

IntroductionLeigh Syndrome is an uncommon cause of infantile apnea.Case summaryWe report a 5-month-old girl with sudden respiratory arrest followed by episodic hyper- and hypo-ventilation, encephalopathy, and persistent lactic acidosis. Computed tomography of the brain revealed symmetric low densities over the basal ganglia, internal capsule, thalami, and midbrain. Cardiac echocardiogram was suggestive of hypertrophic cardiomyopathy.DiscussionDiagnosis of Leigh syndrome due to T8993G mutation was confirmed with polymerase chain reaction and direct DNA sequencing of mitochondrial genome. To our knowledge, this is the first report of proven maternally inherited Leigh syndrome in Hong Kong.

Severe acute respiratory syndrome coronavirus infection in children

Severe acute respiratory syndrome (SARS) was coined by the World Health Organization (WHO) 1 to describe an unusual form of severe pneumonia that first appeared in Guangdong Province, China, in November 2002. On 12 March 2003, the WHO issued a global alert on SARS. 2 At the time of writing, there were 1755 confirmed cases of SARS with 299 deaths in Hong Kong. 3 A treatment regime of ribavirin and systemic corticosteroid was reported in adults and children. 4–6 A novel coronavirus was suggested to be the cause of SARS. 4,7 It was proposed to be named after the late Dr Carlo Urbani who alerted the WHO to ‘something strange and different’ on 5 March 2003. 7 We report here five children and teenagers who showed evidence of SARS coronavirus infection. We analyzed, retrospectively, five children who were found to have pneumonia with evidence of the SARS coronavirus infection, that is, positive reverse-transcriptase – polymerase chain reaction (RT-PCR) and/or serological evidence of infection. Details of RT-PCR and serological tests have been published previously. 4 Clinical features, investigation results, treatment and outcome are listed in Table 1.

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.