Low incidence of pulmonary hypertension in children with suspected obstructive sleep apnea: A prospective observational study.

OBJECTIVES: Pulmonary hypertension (PH) secondary to obstructive sleep apnea (OSA) is an uncommon but serious perioperative risk factor in children undergoing surgery for adenotonsillar hypertrophy. Routine pre-operative echocardiography is commonly requested if severe OSA is suspected. We investigated the incidence of PH in children with suspected OSA and explored the association between PH and OSA severity. METHODS: A prospective study of children aged 1-13 years with suspected OSA admitted for overnight oximetry (OO) and echocardiography at a pediatric referral hospital in Cape Town, South Africa from 2018 to 2019. OSA severity was defined by McGill Oximetry Score (MOS): MOS 1-2 (mild-moderate) and MOS 3-4 (severe). PH was defined as mean pulmonary arterial pressure (mPAP) ≥20 mmHg estimated on echocardiographic criteria. Children with congenital heart disease, underlying cardio-respiratory or genetic disorders, and severe obesity were excluded. RESULTS: One hundred and seventy children median age 3.8 years (IQR 2.7-6.4) were enrolled and 103 (60%) were female. Twenty-two (14%) had a BMIz >1.0 and 99 (59%) had tonsillar enlargement grade 3/4. One hundred and twenty-two (71%) and 48 (28%) children had mild-moderate and severe OSA, respectively. Echocardiographic assessment for PH was successful in 160 (94%) children of which eight (5%) had PH with mPAP 20.8 mmHg (SD 0.9): six with mild-moderate OSA and two with severe OSA. No significant difference in mPAP and other echocardiographic indices was observed in children with mild-moderate (16.1 mmHg; SD 2.4) and severe OSA (15.7 mmHg; SD 2.1). Similarly, no clinical and OSA severity differences were observed in children with and without PH. CONCLUSION: PH is uncommon in children with uncomplicated OSA and there is no association of PH with severity of OSA measured by OO. Routine echocardiographic screening for PH in children with clinical symptoms of OSA without co-morbidity is unwarranted.

Clinical correlations to distinguish severe from milder forms of obstructive sleep apnoea syndrome using overnight oximetry for prioritising adenotonsillectomy in a limited-resource setting.

BACKGROUND: In resource-poor settings with limited surgical services, it is essential to identify and prioritise children with severe and very severe obstructive sleep apnoea syndrome (OSAS) to expedite surgery. McGill's Oximetry Score (MOS) has been validated against polysomnography for OSAS and is affordable and easy to use. AIMS: The aim of this study was to assess the correlation of tonsillar size and clinical symptoms with MOS grade 3 or 4, to identify who requires overnight oximetry and who to prioritise for adenotonsillectomy. METHODS: Children with suspected OSAS were recruited from the otolaryngology clinic at the Red Cross War Memorial Children's Hospital. Demographics, symptom screening scores (SSS), patient characteristics, overnight oximetry (OO), echocardiography and MOS scores (graded 1-4) were recorded. Multivariate modified-Poisson regression models were used to examine correlations of patient characteristics 'with grade 3 or 4 MOS. RESULTS: One-hundred-and-three children were analysed, 38% were female, and median (IQR) age was 3.8 (2.5-5.3) years. Increased tonsil size was associated with a 60% increased risk of grade 3 or 4 MOS, risk ratio (RR) 1.59, 95% CI 1.10-2.29 (p = 0.014). Children with witnessed apnoeic events during sleep had 1.3 times increased risk of MOS Grade 3 or 4, RR 1.31, 95% CI (p = 0.033). A significant correlation was shown with grade 3 or 4 MOS, RR 1.15, 95% CI 1.03-1.27 (p = 0.010) by combining tonsillar size with the following symptoms: apnoeic events; struggling to breathe during sleep and needing to stimulate the child to breathe. CONCLUSION: Identifying children with suspected OSAS who require overnight oximetry can be performed using a simple 3-question screening tool: witnessed apnoeic events, struggling to breathe and the need to shake them awake to breathe. This is more precise with an additional clinical finding of grade 3 or 4 tonsils. These children should have surgery expedited. Any child with a MOS 3 or 4 score on OO needs to have expedited surgery.