The study is an open, prospective, single center clinical observational pilot investigation. The aim is to compare the carbon dioxide values measured by the IscAlert sensor, which is inserted in proximity to the nasal mucosa. The study wants to investigate if the nasal mucosa application and measurements are feasible, what kind of possible complications such a measurement can cause, and if the measurements can be a surrogate marker for systemic carbon dioxide values.

he study is an open, prospective, single center clinical observational pilot investigation including 9 patients and 2 healthy volunteers. The aim is to compare the carbon dioxide values measured by the IscAlert sensor, which is inserted in proximity to the nasal mucosa, with the transcutaneous carbon dioxide values measured at the forehead by a transcutaneous carbon dioxide-monitor, the arterial carbon dioxide measurements performed by blood gas analyses, and carbon dioxide measurements registered with the IscAlert sensor implanted in the muscle of the forearm. The study wants to investigate if the nasal mucosa application and measurements are feasible, what kind of possible complications such a measurement can cause, and if the measurements can be a surrogate marker for systemic carbon dioxide values. The study will include patients with a tendency to hypoventilation, thereby giving rise to a carbon dioxide retention; 3 patients with chronic obstructive pulmonary disease with suspected hypercapnic respiratory failure who are evaluated for non-invasive mask-treatment and long-term oxygen treatment supply if needed. 3 patients with neuromuscular disorders and 3 patients with obesity hypoventilation syndrome who are evaluated for non-invasive mask treatment. The measurements will last for about 8 to 14 hours at night while the patients are sleeping. In addition, the study will also include 2 healthy volunteers as a control group. They will have the equipment mounted on them for about 8 hours during the day in connection with normal office work. Follow up by telephone 7 days +/-2 days after the measurements are finished. The inclusion period is expected to be about 9 months.

Inclusion Criteria:

The subject must meet all of the following inclusion criteria at the time of enrolment:

EITHER

1. Patient are at risk of hypoventilation and thus carbon dioxide retention.

2. Either

   1. Under evaluation for treatment with non-invasive ventilation and maybe Long term oxygen treatment due to chronic obstructive pulmonary disease or
   2. Under evaluation for non-invasive ventilation support due to Obesity hypoventilation syndrome or due to a neuromuscular disorder.

   OR

3. Healthy volunteers

   ALL subjects:

4. Subject must be 18 years or older

5. Subject must be able to give written informed consent

Exclusion Criteria:

1. Known allergy to local anesthetics.
2. Participants should not have any kind of (direct or indirect) affiliation to Sensocure AS
3. Healthy volunteers: No heart-, lung-, or circulatory diseases, no bleeding disorder, no sleep disorders
4. Healthy volunteers should not have any kind of (direct or indirect) acquaintanceship to the investigators
5. Active smoker/use of snuff

Nine patients will be selected consequtive from the hypoventilation assessment planning program at the site. Additionally, two healthy individuals, who have no heart-, lung-, or circulatory diseases, no bleeding disorder, no sleep disorders, and no ties whatsoever to the sponsor (Sensocure AS), will be included as volunteers. Otherwise completely freely chosen by the investigators except they must not have any kind of (direct or indirect) acquaintanceship to the investigators. Eligible subjects will be invited to participate in this clinical investigation. All the subjects will be included at least one day before study procedure starts.

No plan to share IPD to other researchers