Obstructive Sleep Apnoea (OSA) is a disorder involving pauses (apnoea) or restrictions in breathing during sleep. It is caused by the repeated collapse of the upper airways and is characterised by frequent drops in oxygen levels and repeated disruption to sleep. Surgical removal of the tonsils is the first line treatment for most children suffering from OSA. However, this airway surgery is associated with a high rate of complications with approximately 50% of the children suffering from serious breathing problems during and/or after surgery. Disorders such as OSA and other factors such as young age are known to increase children’s risk of suffering from these breathing problems, both during and after anaesthesia which often result in an increased need of attention and specialised care.
The ‘gold standard’ test for diagnosis and classification of OSA is the use of a complex and expensive technique called polysomnography (PSG) involving an overnight sleep study. The associated high cost and lengthy waiting list means that it is rarely used in clinical practice in this population. Currently, surgeons and anaesthetists assess these children’s risk of respiratory complications by taking their clinical history and through questionnaires. Children at an increased risk of respiratory complications can be missed through this identification process and their airway management strategies may not be conservative enough to minimise the risk of respiratory complications during and after their procedure.
Given the challenges in providing safe and timely treatment for this population within the current health budget, our multidisciplinary team has formed a collaborative group to explore the ability of an alternative objective measurement to assess the presence and severity of OSA in these children. Since OSA involves a highly collapsible upper airway during sleep and anaesthesia, we have adopted a method to measure the likelihood of collapse of the upper airway (throat) under anaesthesia to predict OSA severity. The more severe the OSA, the higher the risk of respiratory complications. This safe, simple and quick technique, that can be implemented in routine practice will provide anaesthetists with a new screening method and allow evidence-based risk stratification of this high risk population.
The aim of this study was to determine the efficacy of an objective measure of airway collapsibility (Pclose) in assessing presence and severity of OSA by comparing with the gold standard technique of Polysomnography (PSG) in children undergoing elective tonsillectomy (+/- adenoidectomy). We compared the ability of Pclose to predict incidence of peri-operative respiratory adverse events in children undergoing tonsillectomy (+/- adenoidectomy) with PSG results as well as with the current clinically applied questionnaires.
Professor B S Regli-von Ungern-Sternberg, University of Western Australia and Perth Children’s Hospital
The project was awarded funding of $A102,428 through the ANZCA research grants program for 2017.
We conducted a trial of 65 children aged 1-8 undergoing tonsillectomy (+/- adenoidectomy) at Perth Children’s Hospital. The children underwent an overnight sleep study prior to surgery which was repeated at least 6 weeks post-surgery to assess the presence of Obstructive Sleep Apnoea (OSA) and any improvements in OSA after surgery. In addition airway collapsibility measures (PClose) were taken in anaesthetic induction as well as post-surgery in theatre. Pre surgery Pclose measures were moderately correlated with the pre surgery obstructive apnoea hypopnea index (OAHI) from the overnight sleep study indicating those that had a more collapsible airway had a greater severity of OSA. Preliminary analysis has indicated that an overall presence of a respiratory event was not associated with a change in PClose measures from pre to post surgery, however further analysis will be conducted to assess if there were any specific respiratory events or time frames that were related to a change in airway collapsibility pre to post surgery. Analysis has also shown that an improvement in PClose between the pre and postoperative measurements is related to a lower severity of postoperative OSA as measured by the post-surgery sleep study. We conclude that the PClose measure could be used as a simple cost effective measure to identify high risk children in order to provide better care over the perioperative period.
The results of this study have the potential to better identify children requiring higher-level care and conversely those who can have same day discharge. Such measurements could also reduce the occurrence and severity of respiratory adverse events due to better-informed decision-making regarding perioperative management. The study may also lead to a decrease in the number of unnecessary overnight and intensive care unit admissions, reducing the substantial economic impact on the WA health system while allowing better allocation of valuable hospital resources for other high need patients. Better risk stratification may also have the potential to reduce the stress and subsequent costs to families by facilitating early discharge allowing a larger majority of patients to recover in the comfort and familiarity of their own home.
At present, the statistics are being finalised and the manuscript preparation is in progress.