due to other priorities

This trial compares capnographic signals using a modified CO2/O2 Guedel airway with a CO2/O2 nasal cannula without and with oxygen supply in sedated children aged 4 - 24 months.

Sedation of pediatric patients is frequently jeopardized by respiratory adverse events such as central and/or obstructive apnea resulting in hypoxemia. Various factors such as patient comorbidities, medication and inconsistent physiologic monitoring are known to contribute to or facilitate adverse events during sedation. Therefore, monitoring of breathing by capnography is recommended and has become common standard e.g. by the use of a CO2/O2 nasal cannula.

However, capnography derived from CO2/O2 nasal cannulas may be impaired and these impairments are exaggerated in infants based on their physiologic characteristics (small tidal volumes, high respiratory rates).

To overcome these impairments, the investigators developed a modified CO2/O2 Guedel airway including a CO2 sampling port at the tip of the airway. In a previous study, significantly more accurate capnographic signals resulted compared with measurements derived from a nasal cannula when using a modified CO2/O2 Guedel airway in a model of a breathing 6-month-old manikin.

The aim of the study is to examine the accuracy of capnographic measurements of the modified CO2/O2 Guedel airway in comparison with measurements from a CO2/O2 nasal cannula in sedated children aged 4 - 24 months.

Inclusion Criteria:

• Term born infants aged 4 to 24 months
• Physical status according classification I or II (American Society of Anaesthesiologists (ASA))
• Scheduled for elective diagnostic/therapeutic procedures or surgery under sedation/anaesthesia
• Informed Consent as documented by signature of the parents or legal caregiver

Exclusion Criteria:

• syndrome that affects the airway anatomy
• Physical status according classification III or IV (American Society of Anaesthesiologists (ASA))
• Upper respiratory tract infection at present or within the last two weeks before the study
• Previous enrolment into the current study
• Known hypersensitivity or allergic reactions to midazolam, nitrous oxide (N2O), Propofol or Sevoflurane.
• Positive Family History for malignant hyperthermia, Morbus Pompe or ophthalmic operations with gas injection or Sinus- or inner ear surgery.