ISS 4^th Scientific & AGM

Summary Report

The 4^th Scientific & Annual General Meeting of the ISS took place on 23^rd February in the Radisson SAS Hotel at Dublin Airport. It was well attended by various disciplines involved in the delivery of sleep medicine in Ireland.

The first session was chaired by Prof. Walter McNicholas, who introduced eight comprehensive presentations in relation to sleep disordered breathing.

The first speaker was Dr Aine Fitzpatrick from Midland Regional Hospital in Mullingar. She presented a retrospective review on the accuracy of auto-titrating CPAP in predicting an effective pressure for the treatment of Obstructive Sleep Apnoea Syndrome (OSAS) with a fixed pressure CPAP. Overnight polysomnography to determine appropriate CPAP pressure is recommended but is very costly and has limited availability. This study assessed the use of an auto-titrating CPAP at home to predict the appropriate treatment and was successful in 75% of patients. The method was cheaper, less labour intensive and was more widely available and should be considered as an alternative mode of management for patients with OSAS.

The second presentation was by Dr Alan Mulgrew from Bon Secours, Tralee, on risk and severity of motor vehicle crashes in patients with obstructive sleep apnoea hypopnoea syndrome (OSAHS). This study was undertaken in British Colombia and showed that patients with OSAHS are at significantly increased risk of motor vehicle crashes when compared to matched controls, particularly crashes causing injury. It was also found that the rates of crashes causing injury increased incrementally with OSAHS severity, but increased rates of these crashes occur even in patients with mild OSAHS.

The third presentation was by Dr Naveed Baseeth from the Mid Western Regional Hospital, Dooradoyle, Limerick, entitled ‘What happens when you let the dog see the hare!!’ The study was the evaluation of outcome of referrals, made by physicians to Otorhinolaryngolgists for management of sleep related breathing disorders (SRBD) and the positive impact of nasoendoscopy. The factors for successful surgical outcome were lower AHI, lower body mass index, location of collapse, degree of mandibular protrusion, and the presence of fewer co-morbidites. He concluded that the effective management of SRBD depends on an efficient joint team effort by physicians, otolaryngologists, orthodontists and anaesthetists including expert intervention by ENT surgeons.

Dr Mateen Uzbeck, from Merlin Park University hospital gave the fourth presentation on the subject of ‘ a non invasive device to detect endothelial dysfunction in OSAS’. In this study endothelial dysfunction (ED) was measured non-invasively and was based on endothelially mediated responses at the distal phalynx in response to a five minute occlusion of the brachial artery. The objective of the study was to assess endothelial dysfunction in patients referred for polysomnography and to compare with the effects of CPAP. Evidence was found to support ED as a potential mechanistic link for the development of cardiovascular morbidity in OSAS and that CPAP is effective in significantly improving endothelial function in severe OSAS.

Dr Asaad Khan from Midland Regional Hospital, Mullingar, was our fifth speaker of the morning and his presentation detailed the sensitivity and specificity of overnight pulse oximetry in the diagnosis of sleep apnoea syndrome (SAS) The results showed that overnight pulse oximetry (OPO), using an oxygen desaturation index (ODI) ³5, was a highly sensitive screening test for SAS in an Irish population, though limited by low specificity. The recommendation was that in an environment of limited resources with prolonged waiting times, consideration of this method to screen all new referrals with resultant appropriate prioritisation should be considered. This would ensure patients with severe disease as diagnosed by OPO would be eligible for early administration of CPAP to prevent complications such as hypertension and cardiovascular disease, pending formal sleep studies.

Following this Dr Muhammad Farhan ul Haque, from Newcastle hospital, Co. Wicklow, presented his findings on obstructive sleep apnoea in patients with Schizophrenia. The study, in a sample of community based patients with Schizophrenia, showed the presence of OSAS in 44% of subjects. However, it was noted that the occurrence of OSAS was not related to the severity of Schizophrenia, medications such as neuroleptics and benzodiazepines, smoking or alcohol. His results suggest that OSAS should be considered in patients with Schizophrenia who describe symptoms suggestive of sleep disordered breathing and who have associated risk factors to ensure that adequate treatment is prescribed.

The penultimate presentation of the morning session entitled ‘Selective priming of neutrophil surface adhesion molecule expression in OSAS’ was delivered by Dr John Garvey, from the Sleep research laboratory at St Vincent’s University hospital, Dublin. The aim of this research was to determine if OSAS leads to increased numbers of circulating neutrophils and to assess if the degree of neutrophil activation in OSAS is related to disease severity/AHI. It was concluded that neutrophil production was increased, but there was also decreased basal CD11b expression in the neutorophils of patients with OSAS and selective priming of neutrophils in OSAS to fMLP. Dr Garvey recommended that further investigation into the priming stimulus and the effect of CPAP treatment would be worthwhile.

The eight and final presentation before morning coffee was delivered by Dr John O’Brien and was entitled ‘Dentistry’s role in the management of sleep disorders.’ He defined how his team provide and monitor oral appliances in association with physicians, monitor and treat potential side effects of oral appliance therapy and follow up treatment. He also gave an in-depth insight into the various oral appliances used to treat snoring and mild OSAS. These ranged from tongue retaining devices to adjustable and non-adjustable mandibular repositioners. Evidence from the literature demonstrates the effectiveness of these devices indicating that they reduce the AHI to £ 10 or by up to half the untreated value in most cases.

Following coffee and exhibition viewing, Dr Richard Costello chaired the last session and introduced the guest speaker, Prof John Stradling, from the Oxford Centre for Respiratory Medicine, Oxford University who delivered a very informative presentation entitled “Cardiovascular Associations of OSAS” Prof Stradling discussed the different types of research available at present for investigating OSAS and vascular damage and the problems arising from these. There are three main study types, (1) Uncontrolled interventional studies – are there relevant bias negating the results? (2) Cross sectional and cohort studies - are there hidden confounders that negate the results? (3) Published random control trials - do they look at relevant endpoints, or irrelevant surrogates? The conclusions in reviewing the various studies undertaken lead to more unanswered questions, such as why does blood pressure in non-sleepy patients not respond in the same way as in those who have excessive daytime sleepiness (EDS)? Is it sleep fragmentation due to recurrent arousals that leads to both EDS and hypertension rather than the OSA events themselves?  In his summary Prof Stradling stated that OSAS data is a long way behind that of other risk reduction strategies such as BP control, statins, ACE1 etc and that large randomised controlled trials with long term follow-up and valid endpoints in a range of disease severity are required to really answer the questions surrounding the relationship between cardiovascular disease and OSAS.