OVERALL SYNOPSIS

PART A: Systematic evaluation in spontaneously breathing healthy volunteer study participants

• of cumulative duration of manual measures for airway patency and for mask ventilation with airway device prototype (STAIRWAY) vs. standard procedure (no device) during target-controlled induction of mild and moderate-to-deep sedation with propofol in the supine position
• of minimum anteroposterior and lateral transpharyngeal distances at tongue-base and soft-palate levels, determined by magnetic resonance imaging (MRI) with STAIRWAY vs. biteblock or no device during no, mild and moderate-to-deep steady-state sedation with propofol in the supine position.

PART B: Systematic evaluation (in the body position [normally supine] considered most optimal for the procedural intervention) of the cumulative duration

• of adjuvant manual airway support and ventilation
• of respiratory arrest (interrupted monitoring of endtidal carbon dioxide [ETCO2])
• of hypoxemia (hemoglobin saturation of oxygen [SpO2] <95 %), and
• of perceived sedational comfort, of sedational and procedural usability, and of sedational and procedural preference with STAIRWAY vs. standard procedure (biteblock or no device) during PS according to SOC for scheduled diagnostic or therapeutic procedures planned to be carried out under PS with propofol in spontaneously breathing study patients.

NUMBERS OF STUDY PARTICIPANTS

PART A: 12 (6 female) evaluable study participants (adult healthy volunteers).

PART B: 34 evaluable study participants (adult patients).

DURATION OF INVESTIGATION FOR COLLECTION OF STUDY DATA

PART A: Two months (February until March 2024).

PART B: Six months (February until July 2024).

STUDY FOLLOW-UP

PART A: Short-term questionnaire-based follow-up by individual study participants' survey at study site immediately after appropriate awakening from, and completed collection of study data during, mild and moderate-to-deep steady-state sedation.

PART B: Short-term questionnaire-based follow-up by individual study patients', sedationists' and procedural interventionists' surveys at the study site immediately after appropriate awakening from, and completed collection of study data during, PS according to SOC.

PRIMARY STUDY OBJECTIVES

PART A: Randomized paired crossover comparison of MRI-derived minimum anteroposterior and lateral transpharyngeal distances at tongue-base and soft-palate levels during spontaneous breathing of pure oxygen at mild (Observer Assessment of Alertness/Sedation [OAA/S] level 4) and moderate-to-deep (OAA/S level 2-3) sedation - assessed by estimated target organ levels of propofol according to computerized infusion pump settings, and by bedside judgements of OAA/S levels - in the supine body position with STAIRWAY vs. standard procedure (biteblock or no device).

PART B: Randomized unpaired comparison (by continuous systematic observation and recording) of cumulative duration of adjuvant use of manual airway support and ventilation with STAIRWAY vs. standard procedure (no device) during PS according to SOC - assessed by estimated target tissue levels of propofol according to computerized infusion pump settings, by clinical bedside judgements of sedation levels according to OAA/S, and by monitored Bispectral Index Score (BIS) levels - for scheduled diagnostic or therapeutic procedures planned to be carried out under PS with propofol in the body position (normally supine) most optimal for the procedure.

SECONDARY STUDY OBJECTIVES

PART A: Randomized unpaired comparison of cumulative duration of interrupted ETCO2 monitoring, of SpO2 <95 %, and of adjuvant manual airway measures and mask ventilation, with STAIRWAY vs. no device during computerized target-controlled intravenous (iv) infusion (TCI) of propofol to attain mild and moderate-to-deep steady-state levels of sedation. Individual questionnaire-based evaluation of perceived sedational comfort (VAS units).

PART B: Randomized unpaired comparison of incidence and cumulative duration of interrupted ETCO2 monitoring, and of SpO2 <95 %, during PS according to SOC - assessed by algorithm-based estimated target organ levels of propofol, and by clinical bedside judgements of sedation levels according to OAA/S - for scheduled diagnostic or therapeutic procedures planned to be carried out under PS with propofol in the body position (normally supine) most optimal for the procedure with STAIRWAY vs. no device (standard procedure). Individual questionnaire-based evaluation of perceived sedational comfort (VAS units) by unblinded study patients, of perceived sedational usability (VAS units) by unblinded sedationists, and of perceived procedural conditions (VAS units) by blinded interventionists, soon after completion of PS according to SOC with STAIRWAY or no device.

INCLUSION CRITERIA:

PART A: Adult (18-65 years). No known allergy or hypersensitivity to drugs used for routine sedation or to materials (PP or EVA) comprising STAIRWAY. Medically healthy with no comorbidity according to careful investigation by senior anaesthesiologist in charge of the sedation. No in situ magnetic device or implant. No cognitive or psychosocial distress, particularly including claustrofobia. Complete dentation. No mobile teeth, mobile reconstructions or orthodontic braces. Non-pregnant. No ongoing breast-feeding. Ability to communicate in Swedish. Oral and written informed consent to inclusion as healthy volunteer study participant.

PART B: Adult (18 years and above) scheduled for elective diagnostic or therapeutic procedures under PS with propofol. No known allergy or hypersensitivity to drugs used for PS or to materials (PP or EVA) comprising STAIRWAY. Medical comorbidity corresponding to ASA class I-III. No cognitive or psychosocial distress. Complete or partial dentation. No mobile teeth, mobile reconstructions or orthodontic braces. Ability to communicate in Swedish. Oral and written informed consent to inclusion as study participant.

EXCLUSION CRITERIA:

PARTS A-B: Withdrawal of informed consent. Suspected or manifest unforeseen severe allergic reaction. Inability to obtain enough useful study data for practical or medicotechnical reasons.

For practical reasons, study participants, sedationists and study investigators on site cannot be masked to study interventions.

However, procedural interventionists on site and study investigators scrutinizing study outcome data will be masked to study interventions.

The number of enrolled study participants reported below (46) refers to evaluable ones.