P022 Unattended home sleep studies have a high recording failure rate in a preoperative anaesthetic clinic cohort when done as a routine screening procedure for Obstructive Sleep Apnoea (OSA)

Introduction Preoperative screening for OSA is strongly advised but attended laboratory sleep studies have limited availability. Portable unattended sleep monitors, such as ApneaLink, may provide a practical solution for large scale preoperative OSA screening. However, these unattended monitors may be prone to data recording failure. Methods We performed a prospective, uncontrolled, before-after study from March 2017 to December 2018 where patients from a pre-operative anaesthetic clinic were screened for OSA with an ApneaLink home sleep study (AHSS). 24 initial patients were provided with version 1 (v.1) recording instructions, while the next 24 patients received version 2 (v.2) which included colour, more detail and larger pictures compared to v.1. Recording failure was defined as an absence of recorded ApneaLink data. We analysed predictors of recording failure including instruction version and patient factors using logistic regression. Results Thirty-three of 48 (69%) patients successfully completed an AHSS. Failure rate was 31%. Median duration of recorded data was 480 minutes. The successful recording group was more likely to have used v.2 instructions than the failure group (61% vs. 27%; p=0.029). The odds ratio for successful recording using v.2 was 4.2 (95% CI: 1.1–16.2). Age, gender, country of birth, and number of days prior to surgery were not associated with recording failure. Discussion There was a high failure rate of AHSS for OSA screening from a preoperative anaesthetic clinic. Clear written instructions with greater use of colours and pictures may improve the recording success rate in this cohort.

P015 Home (Level 2) sleep studies are feasible in children

Introduction In-hospital polysomnography (PSG or Level 1 study) is the “gold-standard” for investigating sleep disorders in children. There are long waiting lists for sleep studies in Australian tertiary centres. Level 2 home-PSG has been proposed as an alternate option. However, there are limited data regarding the feasibility in a clinical population. The aim of this study is to assess the feasibility and patient experience of home-PSG in a clinical cohort. Methods The signal quality and outcomes of a home-PSG in young people undergoing sleep investigation in a single centre were reviewed. A successful home-PSG was defined as a study with ≥ 6hrs of sleep and all channels present for ≥90% of sleep time. Feedback from the guardian/young person was collected using a questionnaire. Results Fifty-five patients (4m-18yrs) were included. Successful home-PSG, on the first attempt, was achieved for 48/55 (87%) patients. There were no differences in success when accounting for neurodevelopmental conditions, OSA severity or age. A clinical diagnosis was confidently made in 53 (96%) patients. The majority (76%) rated their sleep as the same or better than normal and only 12% found having the study conducted at home difficult. Following the study, only 8% would have preferred a hospital sleep study. Discussion Home-PSG produced technically adequate recordings for most subjects and families found the experience of having a home sleep study to be positive. These data support, in appropriate circumstances, home-PSG as a viable alternative to an in-patient sleep study.

Revisiting level II sleep studies in the era of COVID-19: a theoretical economic decision model in patients with suspected obstructive sleep apnea

Background The recent pandemic has made it more challenging to assess patients with suspected obstructive sleep apnea (OSA) with in laboratory polysomnography (PSG) due to concerns of patient and staff safety. The purpose of this study was to assess how Level II sleep studies (LII, full PSG in the home) might be utilized in diagnostic algorithms of suspected OSA using a theoretical decision model. Methods We examined four diagnostic algorithms for suspected OSA: an initial PSG approach, an initial LII approach, an initial Level III approach (LIII, limited channel home sleep study) followed by PSG if needed, and an initial LIII approach followed by LII if needed. Costs per patient assessed was calculated as a function of pretest OSA probability and a variety of other variables (e.g. costs of tests, failure rate of LIII/LII, sensitivity/specificity of LIII). The situation in British Columbia was used as a case study. Results The variation in cost per test was calculated for each algorithm as a function of the above variables. For British Columbia, initial LII was the least costly across a broad range of pretest OSA probabilities (< 0.80) while initial LIII followed by LII as needed was least costly at very high pretest probability (> 0.8). In patients with a pretest OSA probability of 0.5, costs per patient for initial PSG, initial LII, initial LIII followed by PSG, and initial LIII followed by LII were: $588, $417, $607, and $481 respectively. Conclusions Using a theoretical decision model, we developed a preliminary cost framework to assess the potential role of LII studies in OSA assessment. Across a broad range of patient pretest probabilities, initial LII studies may provide substantial cost advantages. LII studies might be especially useful during pandemics as they combine the extensive physiologic information characteristic of PSG with the ability to avoid in-laboratory stays. More empiric studies need to be done to test these different algorithms.

Sleep Disordered Breathing Measures in Early Pregnancy Are Associated with Depressive Symptoms in Late Pregnancy

Sleep disordered breathing (SDB) and depression are both common complications of pregnancy and increase risk for adverse maternal and neonatal outcomes. SDB precedes onset of depression in non-pregnant adults; however, the longitudinal relationship has not been studied in pregnancy. The present research examined temporal associations between SDB and depressive symptoms in 175 pregnant women at risk for SDB (based on frequent snoring and obesity), but without an apnea hypopnea index of ≥5 events per hour at enrollment. Women completed a self-report assessments of depressive symptoms using PHQ-9 and in-home level III sleep apnea monitoring at approximately 12- and 32-weeks’ gestation. We also assessed the risk for SDB using the Berlin Questionnaire in early pregnancy. Results revealed that measures of SDB in early pregnancy as assessed by in-home sleep study, but not by self-reported SDB, predicted elevated depressive symptoms in late pregnancy. SDB in late pregnancy was not associated with depressive symptoms. To conclude, these findings suggest that SDB may increase the risk for elevated depressive symptoms as pregnancy progresses.

864 New-onset Obstructive Sleep Apnea Diagnosis in a COVID-positive Patient

Introduction Risk factors for the mortality of COVID-19, such as cardiovascular and lung disease, are commonly seen in patients with obstructive sleep apnea (OSA). Patients with OSA experience approximately 8-fold greater risk for COVID-19 infection compared to a similar age population. Among patients with COVID-19 infection, OSA was associated with an increased risk of hospitalization and approximately doubled the risk of developing respiratory failure. However, there is little information on whether COVID-19 can directly develop OSA. To the best of our knowledge, we describe the first case-presentation of a positive COVID-19 patient who developed sudden-onset OSA. Report of case(s) NL is a 47-year-old female who complains of new-onset snoring, excessive daytime sleepiness, and witnessed apnea events after testing positive for COVID-19 seven months prior after developing mild symptoms. Her ESS score is 12/24, neck circumference is 14.75 cm, BMI is 27.9, and Mallampati II. She has no pertinent PMH and is not a tobacco user. In regards to her sleep, she has no symptoms of restless legs, narcolepsy, or periodic limb movements. She denies any physical disturbances, psychiatric conditions, environmental factors, or medical issues that might affect her sleep. There is no family history of sleep apnea, snoring, or other sleeping disorders. The patient's presentation at the initial sleep visit prompted a home sleep study. Results of her home sleep study revealed 131 total number of sleep-related respiratory events, with an apnea-hypopnea index of 11.9 per hour. Mean oxygen saturation was 94% and the minimum oxygen saturation was 83%. Total estimated sleep time was 7 hours, 59 mins, and sleep quality and duration were deemed adequate. The results from NL's sleep study gave the final diagnosis of mild OSA. Conclusion Besides having a slightly overweight BMI, NL had relatively few risk factors for developing OSA (no family history, no comorbidities, and normal physical exam findings). The link between the virus and the development of OSA in healthy individuals is not readily apparent. We recommend sleep studies for healthy patients who develop OSA like-symptoms after being infected with COVID-19 to prevent unwanted health risks associated with OSA. Support (if any):