Detecting Systemic Carbon Dioxide Levels With a Novel Biosensor

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.

• IscAlert sensor (Device): Insertion of an IscAlert sensor at the nasal mucosa

Primary outcomes

• Partial pressure (level) of carbon dioxide at the nasal mucosa [14 hours]: Nasal mucosa's partial pressure of carbon dioxide (kPa) during insertion period

Secondary outcomes

• Bleeding [7 days]: Amount of blood from insertion site (ml)
• Infection [7 days]: Infection from insertion site at the discretion of the investigator (yes or no)
• Sinusitis [7 days]: Developement of sinusitis at the discretion of the investigator (yes or no)
• Ulceration [7 days]: Developement of ulceration at the nasal mucosa at the discretion of the investigator (yes or no)
• Pain at sensor insertion site [7 days]: Pain at the insertion site measured by Numeric Rating Scale (0= no pain, 10= maximum pain)

Other outcomes

• Muscular temperature level [14 hours]: Muscular temperature level (grade Celsius) during insertion period
• Nasal temperature level [14 hours]: Nasal temperature level (grade Celsius) during insertion period
• Temporal temperature level [14 hours]: Temporal temperature level (grade Celsius) during insertion period
• IscAlert functionality [14 hours]: Number of hours with a well-functioning sensor (giving carbon dioxide- and temperature data)
• Number of pack-years [7 days]: Smoking habit; number of pack-years by participants
• Length of sensor implantation time [7 days]: Length of sensor implantation time during hospitalisation
• Peripheral oxygen saturation [14 hours]: Peripheral oxygen saturation (SpO2)
• Arterial partial pressure (level) of carbon dioxide [14 hours]: Arterial partial pressure of carbon dioxide (kPa) during insertion period - measured in arterial blood
• Arterial partial pressure (level) of oxygen [14 hours]: Arterial partial pressure of oxygen (kPa) during insertion period - measured in arterial blood
• Intramuscular partial pressure (level) of carbon dioxide [14 hours]: Intramuscular partial pressure of carbon dioxide (kPa) during insertion period - measured in the forearm
• Transcutaneous partial pressure (level) of carbon dioxide [14 hours]: Transcutaneous partial pressure of carbon dioxide (kPa) during insertion period, measured at the skin of the forehead
• Patient-Reported Outcome Measures 1a - discomfort [14 hours]: Discomfort in the nose - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 1b - discomfort [7 days]: Discomfort in the nose - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 2a - runny nose [14 hours]: Runny nose - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 2b - runny nose [7 days]: Runny nose - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 3a - sneezing [14 hours]: Sneezing - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 3b - sneezing [7 days]: Sneezing - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 3b - Ulceration [7 days]: Ulceration in the nose mucouse membrane - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 3a - Ulceration [14 hours]: Ulceration in the nose mucouse membrane - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 4a - tenderness [14 hours]: Tenderness in the nose - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 4b - tenderness [7 days]: Tenderness in the nose - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 5b - bleeding [7 days]: Bleeding from the nose - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 5a - bleeding [14 hours]: Bleeding from the nose - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 6a - reduced sense of smell [14 hours]: Reduced sense of smell - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 6b - reduced sense of smell [7 days]: Reduced sense of smell - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 7b - reduced sense of taste [7 days]: reduced sense of taste - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 7a - reduced sense of taste [14 hours]: reduced sense of taste - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 8a - difficulty sleeping [14 hours]: difficulty sleeping - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 8b - easy to wake up while sleeping [7 days]: easy to wake up while sleeping - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 9 - problems with eating and drinking [14 hours]: problems with eating and drinking - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 10 - difficult breathing [14 hours]: difficult breathing - Patient-Reported Outcome Measure, Scale 1 to 5 (1= no, 2= little, 3=Some, 4=very 5=Extreme)
• Patient-Reported Outcome Measures 11a - diagnosed infection in the nose or sinuses [14 hours]: diagnosed infection in the nose or sinuses - Patient-Reported Outcome Measure, Scale 1 to 2 (1= No, 2= Yes)
• Patient-Reported Outcome Measures 11b - diagnosed infection in the nose or sinuses [7 days]: diagnosed infection in the nose or sinuses - Patient-Reported Outcome Measure, Scale 1 to 2 (1= No, 2= Yes)

Sex: All, ages: 18 Years to 110 Years

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

• Anne-Marie Gabrielsen, MD, PhD, Principal investigator, The Hospital of Vestfold