By integrating a miniaturized pulse oximetry sensor into the frame of oxygen delivery glasses which dissimulates the nasal cannula, the investigators hope to optimize and long term oxygen therapy (LTOT) regarding medical and social aspects. The validation of the novel SpO2 sensor is the first step in the concept of personalized, dynamic delivery of oxygen by eyeglasses using a closed-loop system.

Objectives:

1. To determine accuracy of SpO2 measurements by the novel sensor compared to 2 reference pulse oximeters in healthy subjects undergoing a normobaric hypoxic challenge provoking SpO2 desaturation.
2. To determine accuracy of SpO2 measurements by the novel sensor compared to 2 reference pulse oximeters and to arterial blood gas analysis in patients qualifying for LTOT, breathing room air at rest (lying, sitting, standing position) and during exercise (slow walking, 6-MWT, ergometer cycle).

Healthy volunteers

Inclusion Criteria:

• Age 18 - 60 years,
• Non smoker,
• Good general health and physical fitness
• Informed Consent

Exclusion Criteria:

• Current or history of tobacco smoking (> 5 py)
• Current alcohol or drug abuse
• Heart disease or untreated arterial hypertension
• Pulmonary disease
• Epilepsy or other major neurologic disease
• Dark skin colour
• Known anemia
• Severe metabolic disease (e.g. diabetes)
• Pregnancy

Patients

Inclusion Criteria:

• Age ≥ 18 years
• Long term oxygen therapy at rest and/or on physical effort
• Hypoxemia in arterial blood gas analysis at rest PaO2 ≤ 55 mmHg or < 60 mmHg with PHT or polycythemia (men Hb > 174 g/L, women Hb > 140 g/L) or:

Oxygen desaturation on effort (SpO2 < 90%)

• Pulmonary disease including Chronic Obstructive Pulmonary Disease, Interstitial Lung Disease and Sarcoidosis
• Informed Consent

Exclusion Criteria:

• Severe hypoxemia (pO2 <40 mmHg)
• Severe hypercapnia (pCO2 >55 mmHg)
• Acute respiratory infection or systemic infection,
• Severe systolic heart disease (LVEF < 25%)
• Myocardial infarction during the last month before inclusion
• Unstable angina pectoris
• Severe aortic stenosis (mean gradient > 40mmHg, valve area <1 cm2)
• Rhythmogenic heart disease
• Severe or untreated arterial hypertension (blood pressure > 180mmHg systolic, >100mmHg diastolic)
• Anemia (Hb < 120 g/l)
• Known or suspected coagulation disorder (e.g. INR > 4)
• Severe or untreated metabolic disorder
• Neurologic disease or dementia
• Pregnancy
• History of non-compliance to medical treatment
• Current alcohol, drug abuse or current tobacco smoking
• Dark skin color