In patients undergoing spontaneous breathing (SB) deep sedation there is a re-distribution of ventilation towards lungs non-dependant areas (ventral areas in supine position).

Non-invasive ventilation (NIV), offering positive pressure, should favour a better ventilation of dependant areas (dorsal areas in supine position), making ventilation more homogeneous and increasing functional residual capacity.

Electrical impedance tomography (EIT) is a non-invasive, non-operator dependent, bedside, radiations-free diagnostic tool, feasible in paediatric patients and repeatable; it allows to study ventilation distribution, and it can measure and calculate also parameters that are related to the homogeneity of ventilation and the response to certain therapeutic maneuvers, such as anaesthesia or PEEP-application.

Uses of EIT in paediatric age are described in literature, but it has never been described as being used in Non-Operating Room Anaesthesia, nor in other cases of SB deep sedation. In addition, the impact of NIV on the distribution of ventilation in healthy paediatric patients undergoing deep sedation has never been described.

Inclusion Criteria:

• Paediatric age (from 1 to 10 years old)
• ASA score ≤ 2
• Sedation time ≥ 30 min

Exclusion Criteria:

• ASA score ≥ 3
• Lung pathologies (such as asthma, bronchopulmonary dysplasia, obstructive sleep apnoea) Preterm infant
• Severe obesity
• Dorso-lumbar pathologies or other bone pathologies associated with restrictive lung disease (such as scoliosis, kyphosis)
• Neuromuscular, mitochondrial, metabolic or chromosomal disease with hypotonia
• CPAP or NIV treatment at home
• Hand-Bag Ventilation (HBV) during the procedure (loss of the respiratory drive)
• Non-Total IntraVenous Anaesthesia (TIVA), adherence to the sedation protocol
• Implantable devices not compatible with EIT (such as pace-makers and implantable cardioverter defibrillator)