The goal of this prospective observational study is to validate pEEG as a monitoring tool for the analgosedation level in mechanically-ventilated critically ill children, receiving or not-receiving NMBAs. The main question aims to answer is to measure the strength of agreement between pEEG score and Comfort Behavioural Scale (CBS) (goal standard).

Participants will be monitored with pEEG and CBS evaluated during PICU admission. paralysis holiday) by a specialized PICU nurse and by a critical-care expert physician, blinded to each other.

Rationale: The existence of a strong agreement between the two scores will allow us to consider the use of Masimo Sedline® PSI in our routine practice as an additional tool to monitor the analgosedation level of mechanically ventilated critically ill patients, as well as the main tool for chemically paralyzed patients.The final goal of this project is to validate the Masimo Sedline® as a monitoring tool for the analgosedation level in mechanically-ventilated critically ill children, receiving or not-receiving NMBAs.

Specific Aim. To evaluate the strength of agreement between CBS and the Masimo Sedline® PSI in children.

Design: prospective cohort study including all consecutive mechanically ventilated patients receivinganalgosedation admitted to a tertiary-care PICU.

Setting: Tertiary-care Center PICU (Padova University Hospital, Italy). Partecipants: all consecutive patients who will receive mechanical ventilation and consequently analgosedation admitted to our PICU during the study period. Both patients receiving NMBAs and patient not receiving NMBAs will be included (patients with NMBA will be evaluated during a paralysis holiday). Exclusion criteria: patient with skin lesions or other significant traumatic lesions in the area where the Masimo Sedline® sensor need to be applied.

Exposure: All patients will be exposed to the Masimo Sedline® sensor. Its pEEG scores, including the PSI, will be registered by the patient primary nurse every 4 hours for the first 5 days of ventilation. At the same time, CBS will be evaluated by a specialized PICU nurse and by a critical-care expert physician, blinded to each other. In case of CBS discordance between the two operators, a mean will be used for data analysis. In case of chemically paralyzed patients, a paralysis holiday will be performed when clinically possible (ideally twice a day). A CBS will be assessed when the paralytic agents will be considered washed out, i.e. when the patient starts triggering at the ventilator and the EMG index starts showing muscular activity. The patient's analgosedation strategy and analgosedation protocol will not be standardized but will be decided by the treating physician based on the international recommendations.

Main outcome and measures: To evaluate the strength of agreement between the Masimo Sedline® PSI (exposure) and the CBS in mechanically in mechanically ventilated children, adequately or inadequately sedated, and in patients receiving NMBAs (during paralysis holiday).

Analytical plan: Descriptive statistics will be used to describe patients' demographic and clinical characteristics, as well as patient-related clinical outcomes. PSI and CBS will be tested for agreement using K statistics separately in patients with adequate sedation (CBS 11-22), inadequate sedation (CBS <11 or >22), and in patients receiving NMBAs. Multiple sensitivity analyses will be also performed in different subcohort of patients, including neonates, patients with seizures, as well as for different drugs. As an additional analysis, the use of a composite score including the EMG index (i.e. muscular activity) and the EEG suppression ratio (measure of EGG suppression events as index of oversedation) will be included.

Inclusion Criteria:

- sedated and ventilated patients admitted in PICU

Exclusion Criteria:

• skin lesions
• significant traumatic lesions in the area where the Masimo Sedline® sensor need to be applied.

Pediatric patients admitted in PICU who undergone sedation and mechanical (invasive and non invasive) ventilation