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Research Studies


  • The MERGE trial - a multicentre randomised controlled trial of 301 patients - showed that CPAP improves quality of life and daytime sleepiness in patients with symptomatic mild obstructive sleep apnoea. CPAP is now standard practice for these patients as recommended in the latest NICE guidelines (NG202). 
  • The NIVO study - a mutlicentre observational study - validated the NIVO score to predict the risk of mortality for patients with acute decompensated hypercapnic respiratory failure in COPD (Hartley et al. ERJ 2021).
  • Long-term follow-up of the cardiovascular outcomes for patients in the MOSAIC randomised controlled trial showed that CPAP did not reduce cardiovascular complications in patients with minimally symptomatic obstructive sleep apnoea (Turnbull et al. Thorax 2014 and Tang, Turnbull et al. BMJ Open Resp Res 2020). 


  • The UK Sleep Network showed that pathway changes to CPAP set-up after the first wave of the pandemic lead to worse CPAP adherence in a multi-centre evaluation (Turnbull et al. Thorax 2022). 
  • The Oxford Respiratory Group showed improved outcomes in respiratory HDU patients with COVID-19 in a single centre evaluation (Turnbull, Porter et al. BMJ Open Resp Res 2021). 
  • The UKCCMP study showing that systemic anti-cancer therapy did not increase the risk of adverse outcomes in patients with COVID-19 and cancer (Lee et al. Lancet 2020). I carried out statistical analyses as part of this multi-centre collabortation. 
  • Investigator on three COVID-19 trials (SPRINTER trial, ABC-19 trial and the PANORAMIC trial)

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Chris Turnbull


Honorary Researcher

  • Consultant in Respiratory Medicine, Oxford University Hospitals NHS Foundation Trust
  • Non-stipendiary lecturer, St Hugh’s College, University of Oxford
  • Associate Editor for Education, Thorax, BMJ
  • Program Committee Member, American Thoracic Society Conference
  • Advisory board member, Pulmonary Therapy, Springer


I am an honorary researcher in respiratory medicine and respiratory consultant with a specialist interest in sleep related breathing disorders. I run trials investigating the cardiovascular and metabolic consequences of obstructive sleep apnoea and run trials investigating new therapeutic options for patients with obstructive sleep apnoea in collaboration with colleagues in the UK Sleep Network. My work spans lab based biomarker discovery, translational physiological studies and practice changing clinical studies. 

Translational Physiology

  • The SOX trial - a randomised controlled trial utilising the CPAP withdrawal model - showed for first time that intermittent hypoxia is the key determinant of morning blood pressure rises in patients with obstructive sleep apnoea (Turnbull et al. AJRCCM 2019). Previously the relative contributions of arousal and intermittent hypoxia to daytime blood pressure rises was controversial. 
  • The Retinal Reactivity trial - a randomised controlled trial utilising the CPAP withdrawal model - showed that obstructive sleep apnoea does not cause impairments in retinal vascular responses which were thought to be central to the development of diabetic retinopathy in patients with obstructive sleep apnoea and type 2 diabetes mellitus (Turnbull et al. Graefes 2022). 
  •  Showing the relationship between the distribution of adipose tissue and upper airway collapsibility in a cohort of 53 obese individuals (Turnbull et al. Sleep Breath 2018).

Molecular pathways

  • Identification of inflammatory transcriptomic changes induced by intermittent hypoxia in obstructive sleep apnoea which was abolished by supplemental oxygen (Turnbull et al. AJRCCM 2020). 
  • Demonstrating that key biomarkers of systemic oxidative stress  (Turnbull et al. ERJ 2017) and of hypoxia inducible factor activation (Turnbull, Rossi et al. Respirology 2017) are not altered by obstructive sleep apnoea during CPAP withdrawal
  • Identifying procoagulant and platelet derived microvesicles caused by obstructive sleep apnoea as a putative mechanism for the development of cardiovascular disease (Ayers et al. Respiration 2016)

Recent publications

More publications