Evaluation of the safety and efficacy of using the Lumena mask, compared to commercially-available, commonly used Oro-nasal masks.

20 participants will be included in the study. The number of patients for each group is 5.

The trial is, a crossover trial, as all participants go through every one of the trial conditions, albeit in a different order, and thus every trial condition will have results of 20 patients in it eventually.

Prior to patient treatment, the subject will be informed about the study and potential risks, and will be givin written informed consent.

Prior to every inhalation and particle sampling, a baseline sample will be taken to filter possible carryovers from previous sampling.

Demographics including age, sex, DOB, height, weight and body mass index. Past medical history including smoking status, co-morbid conditions and medication use.

Vital signs before, during and after non-invasive ventilation: heart rate, respiratory rate, Tidal volume, oxygen saturation, Mode of ventilation, peak inspiratory pressure, pressure support, Ventilator type and model, Trigger sensitivity, Fio 2%, PEEP, blood pressure (invasive and/or non-invasive) and temperature.

Electrocardiogram (ECG) diagrams before and after use. Arterial blood\ Venous blood gas analysis for O2, CO2, pH and HCO3 as well as serum Lactate levels before, during and after non-invasive ventilation. A maximum of 20 ml of blood will be collected from each patient.

Room aerosol particle concertation in sizes 0.3, 0.5, 1.0 and 2.5µ. Symptoms and signs during use of non-invasive ventilation (e.g. diaphoresis, anxiety).

Estimation of patient preference of the mask - the question shall be phrased thusly: In a Which mask do you prefer? Estimation of staff comfort (an analog 1-5 scale as well as recording of verbal comments). - the question shall be phrased thusly: In a scale of 1-5, 1 being very uncomfortable to use and 5 being very comfortable, to use how would you rate the mask? Estimation of staff use - the question shall be phrased thusly: Which mask do you prefer? Estimation of patient comfort - the question will be directed to the staff member. (an analog 1-5 scale as well as recording of verbal comments) - the question shall be phrased thusly: In a scale of 1-5, 1 being very uncomfortable to use and 5 being very comfortable to use, how would you rate the patient's feeling with the experimental mask? Device related AE's will be reported by number, type, seriousness, severity and duration. All device and treatment related AEs will be captured, regardless of severity.

Inclusion Criteria:

1. Male and female adults, aged 18 years and over.
2. Suffering from hypoxemic and/or hypercarbic respiratory failure requiring non-invasive ventilation and selected by medical staff to use CPAP or BiPAP.
3. Fully concious (Glasgow Coma Scale 14-15) and able to cooperate with non-invasive ventilation.
4. Able to provide informed consent to participate in the study.
5. Have an active arterial line in place for arterial blood sampling (arterial lines will not be placed for the sole purpose of the study). Alternatively, IV line can be used.

Exclusion Criteria:

1. Age < 18 years.
2. Pregnancy.
3. Respiratory failure due to non-pulmonary pathology.
4. Presence of a contraindication to the use of non-invasive ventilation or an absolute indication for invasive ventilation.
5. Presence of a facial deformity, heavy beard or moustache which prevents a good seal between the mask and the face.
6. Hemodynamic instablity.
7. Severe upper gastrointestinal bleeding.
8. Chest trauma.
9. Claustrophobia