Try our beta test site
IMPORTANT: Listing of a study on this site does not reflect endorsement by the National Institutes of Health. Talk with a trusted healthcare professional before volunteering for a study. Read more...

Efficacy Study of CPAP on Nitrate and Norepinephrine Levels in Severe and Mild-moderate Sleep Apnea (SABIO) (SABIO)

This study has been completed.
Information provided by (Responsible Party):
Paula Pinto, University of Lisbon Identifier:
First received: November 17, 2012
Last updated: January 16, 2013
Last verified: January 2013
Reduced plasma nitrate (NOx) levels and increased urinary norepinephrine (U-NE) levels have been described in severe obstructive sleep apnea (OSA), and are reverted by continuous positive airway pressure (CPAP). The investigators wanted to know the effect of CPAP on these biomarkers in mild-moderate OSA.

Condition Intervention
Obstructive Sleep Apnea
Device: CPAP

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: Effects of CPAP on Nitrate and Norepinephrine Levels in Severe and Mild-moderate Sleep Apnea

Resource links provided by NLM:

Further study details as provided by University of Lisbon:

Primary Outcome Measures:
  • Plasma nitrate (NOx) levels [ Time Frame: one month ]
    After sleep apnea diagnosis, measurements of plasma NOx at 11 pm, 4 am and 7 am were obtained at baseline and after 1 month of CPAP.

Secondary Outcome Measures:
  • 24 h Blood pressure [ Time Frame: one month after CPAP ]
    Ambulatory BP were obtained at baseline and after 1 month of CPAP.

  • Urinary norepinephrine (U-NE) levels [ Time Frame: One month ]
    After sleep apnea diagnosis, measurements of urinary norepinephrine levels were obtained at baseline and after 1 month of CPAP.

Enrollment: 67
Study Start Date: July 2004
Study Completion Date: December 2008
Primary Completion Date: December 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: CPAP treatment
67 consecutive male patients with OSA were recruited: 36 with mild-moderate OSA and 31 with severe OSA. Data were collected in all subjects at baseline and after 1 month of CPAP.
Device: CPAP
CPAP adaptation was performed by a sleep technician and the patients were instructed to use this for 1 month.
Other Name: Automated pressure setting device (AutoSet Spirit, ResMed)

Detailed Description:

The investigators aimed to compare NOx and U-NE levels and blood pressure (BP) between male patients with mild-moderate and severe OSA and determine the impact of 1 month of CPAP therapy on these parameters.

The investigators undertook a prospective study of 67 consecutive OSA patients (36 mild-moderate, 31 severe). Measurements of plasma NOx at 11 pm, 4 am and 7 am, 24-h U-NE and ambulatory BP were obtained at baseline and after 1 month of CPAP.


Ages Eligible for Study:   20 Years to 65 Years   (Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   No

Inclusion Criteria:

- Diagnosis of obstructive sleep apnea

Exclusion Criteria:

  • current smoker
  • respiratory disease
  • cardiac disease (except for arterial hypertension)
  • renal disorder
  • hepatic disorder
  • psychiatric disorder
  • diabetes mellitus
  • dyslipidemia
  • rhinitis
  • sinusitis
  • acute illness
  • daytime hypoxemia or hypercapnia
  • therapy with oral nitrates
  • therapy with angiotensin-converting enzyme inhibitors
  • therapy with beta-blockers
  • therapy with statins
  • therapy with non-steroidal anti-inflammatory drugs
  • presence of central respiratory events
  • previous CPAP therapy
  • previous uvulopalatopharyngoplasty
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01769807

Hospital Pulido Valente
Lisbon, Portugal, 1769-001
Sponsors and Collaborators
University of Lisbon
Principal Investigator: Paula G Pinto, PhD University of Lisbon
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Paula Pinto, PhD, University of Lisbon Identifier: NCT01769807     History of Changes
Other Study ID Numbers: CEDOC
Fundação Ciência e Tecnologia ( Other Grant/Funding Number: Fundação para a Ciência e Tecnologia (FCT) )
Study First Received: November 17, 2012
Last Updated: January 16, 2013

Keywords provided by University of Lisbon:
Sleep apnea
CPAP treatment
Plasma nitrate
Urinary norepinephrine
Blood pressure

Additional relevant MeSH terms:
Sleep Apnea Syndromes
Sleep Apnea, Obstructive
Respiration Disorders
Respiratory Tract Diseases
Signs and Symptoms, Respiratory
Signs and Symptoms
Sleep Disorders, Intrinsic
Sleep Wake Disorders
Nervous System Diseases
Adrenergic alpha-Agonists
Adrenergic Agonists
Adrenergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs
Autonomic Agents
Peripheral Nervous System Agents
Vasoconstrictor Agents processed this record on April 28, 2017